Sökning: "Focused wave"

Visar resultat 1 - 5 av 109 avhandlingar innehållade orden Focused wave.

1. 1. Hydrodynamic Modelling for a Point Absorbing Wave Energy Converter

   Författare :Jens Engström; Jan Isberg; Mats Leijon; Antonio Sarmento; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; Ocean wave energy; Point absorber; Wave energy converter; Wave energy transport; Polychromatic wave; Linear generator; Resonance; Finite depth; Modelling; Engineering Science with specialization in Electronics; Teknisk fysik med inriktning mot elektronik;

   Sammanfattning : Surface gravity waves in the world’s oceans contain a renewable source of free power on the order of terawatts that has to this date not been commercially utilized. The division of Electricity at Uppsala University is developing a technology to harvest this energy. LÄS MER

3. 2. Extreme wave conditions and the impact on wave energy converters

   Författare :Eirini Katsidoniotaki; Malin Göteman; Vincent Neary; Uppsala universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; extreme waves; wave energy converters; CFD; OpenFOAM; environmental contours; focused waves; breaking waves;

   Sammanfattning : The amount of energy enclosed in ocean waves has been classified as one of the most promising renewable energy sources. Nowadays, different wave energy conversion (WEC) systems are being investigated, but only a few concepts have been operated in a sea environment. LÄS MER

4. 3. Modelling and Experimental Verification of Direct Drive Wave Energy Conversion : Buoy-Generator Dynamics

   Författare :Mikael Eriksson; Mats Leijon; Jan Isberg; Arne Wolfbrandt; Kim Nielsen; Uppsala universitet; []
   Nyckelord :Engineering physics; Wave energy; Potential wave theory; Linear generator; Simulations; Experiments; Point absorber; FEM; Equivalent circuit theory; Teknisk fysik; TECHNOLOGY; TEKNIKVETENSKAP;

   Sammanfattning : This thesis is focused on development of models and modelling of a wave energy converter in operation. Through the thesis linear potential wave theory has been used to describe the wave-buoy interaction. The differences lie in the generator models, in the simplest model the generator is a mechanical damper characterized by a damping factor. LÄS MER

5. 4. Attosecond Optical and Electronic Wave Packets

   Författare :Per Johnsson; Atomfysik; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; optik; acoustics; optics; Electromagnetism; Ionization Dynamics; Electron Wave Packet Interferometry; Electron Wave Packet Control; Pulse Characterization; High-Order Harmonics; Attosecond Pulse Trains; Atom- och molekylärfysik; Atomic and molecular physics; akustik; Elektromagnetism;

   Sammanfattning : When a low-frequency laser pulse is focused to a high intensity in a gas, the electric field of the laser may become comparable to, or even exceed, the electric field between the electrons and the nucleus in the atom. Under such conditions, through a process known as high-order harmonic generation, bursts of extreme ultraviolet radiation may be emitted, with durations in the attosecond domain (1 as = 10^{-18} s), which is the time-scale of electronic processes. LÄS MER

7. 5. d-wave Josephson Junctions

   Författare :Tobias Lindström; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Josephson junctions; high-temperature superconductivity; Andreev states;

   Sammanfattning : The properties of d-wave YBCO Josephson junctions and dc-SQUIDs with high misorientation angles have beenstudied experimentally .The predominant d-wave symmetry of the pairing wavefunction in high-Tc superconductors has, to a large extent, beena hinderance in applications, but it also makes it possible to fabricate devices with novel properties that may be suitablefor applications in the quantum regime; one particulary interesting property is a strong second harmonic component in the current-phase relation ofjunctions with the electrodes oriented in a node-lobe arrangement; so-called 0-45 junctions. LÄS MER