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Visar resultat 1 - 5 av 149 avhandlingar som matchar ovanstående sökkriterier.

1. 1. Asymptotic and universal spectral estimates with applications in many-body quantum mechanics and spectral shape optimization

   Författare :Simon Larson; Ari Laptev; Stefan Steinerberger; KTH; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Spectral theory; shape optimization; semiclassical asymptotics; spectral inequalities; quantum mechanics; Mathematics; Matematik;

   Sammanfattning : This thesis consists of eight papers primarily concerned with the quantitative study of the spectrum of certain differential operators. The majority of the results split into two categories. LÄS MER

3. 2. On the Military Utility of Spectral Design in Signature Management : a Systems Approach

   Författare :Kent Andersson; Jouko Vankka; Gunnar Hult; Hans Kariis; Hans Liwång; Harold Lawson; Jari Hartikainen; Försvarshögskolan; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; military utility; survivability; signature management; systems engineering; camouflage; Low Observable Technology; spectral design; multi-spectral; Försvarssystem; Military Technology;

   Sammanfattning : There is an ongoing duel between military sensor development and developments in signature management. The last decade, with warfare characterized by joint expeditionary operations and asymmetry, has favored sensors. LÄS MER

4. 3. Optimization of time domain induced polarization data acquisition and spectral information content

   Författare :P.-I. Olsson; Teknisk geologi; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; induced polarization 1P ; DCIP; spectral information; Data quality; Signal Processing;

   Sammanfattning : The need for detailed subsurface information is increasing due to city expansion and infill projects as well as subsurface construction projects. One common method for acquiring this geo-information is the direct current resistivity and time domain induced polarization method (DCIP) that measures the electrical resistivity and chargeability of the subsurface. LÄS MER

5. 4. Wind turbine simulations using spectral elements

   Författare :Elektra Kleusberg; Dan Henningson; Philipp Schlatter; Stefan Ivanell; Johan Meyers; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; wind turbine; wakes; wake interaction; computational fluid dynamics; actuator line method; spectral elements; free-stream turbulence; Engineering Mechanics; Teknisk mekanik;

   Sammanfattning : Understanding the flow around wind turbines is a highly relevant research question due to the increased interest in harvesting energy from renewable sources. This thesis approaches the topic by means of numerical simulations using the actuator line method and the incompressible Navier–Stokes equations in the spectral element code Nek5000. LÄS MER

7. 5. Geometrical controls on spectral induced polarization in time and frequency domain

   Författare :Sara Johansson; Teknisk geologi; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Spectral induced polarization; Microstructure; Electrical properties; Tomography; Multiscale;

   Sammanfattning : What can we learn by transmitting electrical currents through electrodes in the ground? Geophysical methods can help us to locate the bedrock, valuable mineral ores, remains of ancient buildings and many other secrets hiding below the surface. However, it is not only the universal interest for the unknown that drives the geophysical research forward. LÄS MER