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Visar resultat 1 - 5 av 87 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Spectral Inequalities and Their Applications in Quantum Mechanics

   Författare :Fabian Portmann; Ari Laptev; Robert Seiringer; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Spectral inequalities; quantum mechanics; Hardy inequalities; Sobolev inequalities; Lieb-Thirring inequalities; stability of matter; Bose gases; Bose-Einstein condensation; Mathematics; Matematik; Fysik; Physics;

   Sammanfattning : The work presented in this thesis revolves around spectral inequalities and their applications in quantum mechanics.In Paper A, the ground state energy of an atom confined to two dimensions is analyzed in the limit when the charge of the nucleus Z becomes very large. LÄS MER

3. 2. Stability results for viscous shock waves and plane Couette flow

   Författare :Mattias Liefvendahl; KTH; []
   Nyckelord :nonlinear stability; shock waves; Couette flow; Chebyshev spectral method; resolvent estimates; threshold amplitudes;

   Sammanfattning : .... LÄS MER

4. 3. Spectral analysis in laser powder bed fusion

   Författare :Benedikt Brandau; Frank Brückner; Alexander Kaplan; Dan Roth-Fagaraseanu; Luleå tekniska universitet; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Spectral monitoring; Laser powder bed fusion; Laser optics; Absorbance; Produktionsutveckling; Manufacturing Systems Engineering;

   Sammanfattning : This thesis is about the investigation of the spectral interaction of electromagnetic radiation with metal powders. For this purpose, spectral data of powders for laser powder bed fusion processes are investigated in three papers using different techniques. LÄS MER

5. 4. The Effect of Different Perturbations on the Stability Analysis of Light Water Reactors

   Författare :Victor Dykin; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; NATURVETENSKAP; NATURAL SCIENCES; BWR and PWR stability; stability indicators; propagating density perturbation; autocorrelation function; density wave oscillations; decay ratio; non-white driving force; damped harmonic oscillator; reduced order models; Green s function technique;

   Sammanfattning : Neutron noise analysis techniques are studied and developed, with primary useof determining the stability of Boiling Water Reactors (BWRs). In particular, the role ofa specific perturbation prevailing in Light Water Reactors, the propagating densityperturbation, in the stability of BWRs and on the noise field of LWRs in general, isinvestigated by considering three topics. LÄS MER

7. 5. Global stability analysis of three-dimensional boundary layer flows

   Författare :Mattias Brynjell-Rahkola; Dan Henningson; Philipp Schlatter; Ardeshir Hanifi; Spencer Sherwin; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Hydrodynamic stability; transition to turbulence; global analysis; boundary layers; roughness; laminar flow control; Stokes Laplace preconditioner; optimal forcing; crossflow vortices; Ginzburg-Landau; Falkner-Skan-Cooke; Blasius; lid-driven cavity;

   Sammanfattning : This thesis considers the stability and transition of incompressible boundary layers. In particular, the Falkner–Skan–Cooke boundary layer subject to a cylindrical surface roughness, and the Blasius boundary layer with applied localized suction are investigated. LÄS MER