Search for dissertations about: "self-sustained oscillations"

Found 5 swedish dissertations containing the words self-sustained oscillations.

2. 1. Aeroacoustics Studies of Duct Branches with Application to Silencers

   Author : Mikael Karlsson; Mats Åbom; Luc Mongeau; KTH; []
   Keywords : TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; silencer; muffler; confined flows; flow duct; aeroacoustics; vortex sound; acoustic multiports; linear stability; self-sustained oscillations; whistling; Herschel-Quincke tube; acoustic resonator; Fluid mechanics; Strömningsmekanik;

   Abstract : New methodologies and concepts for developing compact and energy efficient automotive exhaust systems have been studied. This originates in the growing concern for global warming, to which road transportation is a major contributor. READ MORE

4. 2. Fighting flameless fires : Initiating and extinguishing self-sustainedsmoldering fires in wood pellets

   Author : Ragni Fjellgaard Mikalsen; Vidar Frette; Bjarne C. Hagen; Ulrich Krause; Anne Steen-Hansen; Ulrich Krause; Nieves Fernandez-Anez; RISE; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Fuel storage safety; Industrial fire; Biofuels; Smoldering; Extinguishment; Fire suppression; Fire growth; Fire spread; Heat transfer; Nonlinear dynamics; Complex systems; Combustion; Biomass energy; Synchronization; Oscillations; EMRIS;

   Abstract : Smoldering fires represent domestic, environmental and industrial hazards. This flameless form of combustion is more easily initiated than flaming, and is also more persistent and difficult to extinguish. The growing demand for non-fossil fuels has increased the use of solid biofuels such as biomass. READ MORE

5. 3. 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

6. 4. Oscillatory phenomena in chloroplasts from spinach cotyledons

   Author : Gertrud Puu; Umeå universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES;

   Abstract : A suspensionofchloroplasts, isolated from spinach cotyledons, was found to be an oscillatory system, i.e. a system in which one parameter (or more) varies over time in a fairly regular way.The oscillations, with a period of fifteen to twenty minutes,occured spontaneously in the light as well as in the dark and were self-sustained for several hours. READ MORE

7. 5. Electronic Control of Flexural Nanowire Vibrations

   Author : Fabio Santandrea; Göteborgs universitet; []
   Keywords : NATURVETENSKAP; NATURAL SCIENCES; Nanoelectromechanical systems; Carbon nanotubes; Coulomb blockade; Shuttle instability; Ground-state cooling;

   Abstract : “Nanoelectromechanical systems” (NEMS) are nanometer-sized mechanical structures coupled to electronic devices of comparable size. The coupling between mechanical and electronic degrees of freedom, combined with their mesoscopic size, provide these systemswith some unique properties that make them interesting from both the fundamental and technological point of view. READ MORE