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Showing result 1 - 5 of 1550 swedish dissertations matching the above criteria.

2. 1. Analysis and control of transitional shear flows using global modes

   Author : Shervin Bagheri; Dan Henningson; Alessandro Bottaro; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fluid mechanics; flow control; hydrodynamic stability; global modes; jet in crossflow; flat-plate boundary layer; laminar-turbulent transition; Arnoldi method; Koopman modes; balanced truncation; direct numerical simulations.; Fluid mechanics; Strömningsmekanik;

   Abstract : In this thesis direct numerical simulations are used to investigate two phenomenain shear flows: laminar-turbulent transition over a flat plate and periodicvortex shedding induced by a jet in cross flow. The emphasis is on understanding and controlling the flow dynamics using tools from dynamical systems and control theory. READ MORE

4. 2. Prediction of engine component loads using previous measurements

   Author : Pär Mikaelsson Elmén; Mårten Olsson; Jan-Olov Aidanpää; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; engine; engine block vibration; engine block twist; engine block bending; vibration measurement; vibration estimation; rigid body vibrations; assumed modes; bending modes; torsion modes; system modification; Hållfasthetslära; Solid Mechanics;

   Abstract : Internal combustion engines are used in many applications. The same engine type may have different components mounted to it depending upon its use. These engine mounted components need to be designed against fatigue in order to withstand the engine vibrations. Measured engine vibrations are commonly used as input data for fatigue estimation. READ MORE

5. 3. Systematic Antenna Design Using the Theory of Characteristic Modes

   Author : Zachary Miers; Institutionen för elektro- och informationsteknik; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Theory of Characteristic Modes; Antenna Design; Antenna; Characteristic Modes; Computational Electromagnetics; MIMO Systems; MIMO Antenna; MIMO; Mutual Coupling; Mobile Antenna;

   Abstract : The day Faraday moved a magnet in and out of a wire loop and detected the time-varying magnetic field, the first wireless transmitter / receiver system was created and the world was changed forever. However, it took almost fifty years for Heinrich Hertz to use Maxwell's equations and Faraday's insights in his professorship at Karlsruhe to create the first electromagnetic wireless communication system using a spark gap dipole transmitter and a loop antenna-based receiver. READ MORE

6. 4. Modes of Mathematical Modelling : An analysis of how modelling is used and interpreted in and out of school settings

   Author : Peter Frejd; Christer Bergsten; Jonas Ärlebäck Bergman; Rudolf Strässer; Linköpings universitet; []
   Keywords : SAMHÄLLSVETENSKAP; SOCIAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

   Abstract : The relevance of using mathematics in and for out-of-school activities is one main argument for teaching mathematics in education. Mathematical modelling is considered as a bridge between the mathematics learned and taught in schools and the mathematics used at the workplace and in society and it is also a central notion in the present Swedish mathematical syllabus for upper secondary school. READ MORE

7. 5. Low-Energy Modes of Molecules and Atoms Chemisorbed on a Metal Surface. CO and O on Pt(111) Studied by Infrared Spectroscopy

   Author : Ulrika Engström; Chalmers tekniska högskola; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; dipole-allowed modes; low-energy modes; carbon monoxide; Infrared spectroscopy; dipole-forbidden modes; Pt 111 ; anti-absorption; Fermi resonance; atomic oxygen;

   Abstract : This thesis is devoted to the investigation of low-energy metal-adsorbate vibrational modes of CO molecules and O atoms chemisorbed on a Pt(111) surface using infrared spectroscopy (IRS). The infrared selection rule states that only vibrational modes having a non-vanishing component of its dynamical dipole moment perpendicular to the surface can be directly excited using IRS, known as dipole-allowed modes. READ MORE