Sökning: "plane-wave"

Visar resultat 1 - 5 av 67 avhandlingar innehållade ordet plane-wave.

1. 1. Plane wave electromagnetic measurements for imaging fracture zones

   Författare :Lena Persson; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Geophysics; Electromagnetic Measurements Fracture Zones; Geofysik; Geophysics; Geofysik; Geofysik med inriktning mot fasta jordens fysik; Geophysics with specialization in Solid Earth Physics;

   Sammanfattning : Electromagnetic fields from distant radio transmitters interact with the resistivity structures in the earth. They can be regarded as plane-wave fields since their penetration depth is much smaller than their wavelength. LÄS MER

3. 2. Tensionless Strings and Supersymmetric Sigma Models : Aspects of the Target Space Geometry

   Författare :Andreas Bredthauer; Ulf G. Lindström; Bengt E.W. Nilsson; Uppsala universitet; []
   Nyckelord :Theoretical physics; Theoretical Physics; String Theory; Tensionless Strings; Supergravity Backgrounds; Plane Wave; Supersymmetry; Non-linear Sigma Models; Generalized Complex Geometry; Teoretisk fysik;

   Sammanfattning : In this thesis, two aspects of string theory are discussed, tensionless strings and supersymmetric sigma models.The equivalent to a massless particle in string theory is a tensionless string. Even almost 30 years after it was first mentioned, it is still quite poorly understood. LÄS MER

4. 3. Controlled Source Radiomagnetotelluric (CSRMT) Applications in Environmental and Resource Exploration

   Författare :Nazli Ismail; Laust Pedersen; Bulent Tezkan; Uppsala universitet; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; Magnetotelluric; radio magnetotelluric; controlled-source tensor magnetotelluric; plane wave; near surface geophysics; sediment; fracture zone; inversion; forward modelling; near field effect; two-dimensional model; three-dimensional model; resolution; Geophysics; Geofysik; Earth Sciences with Specialization Environmental Analysis; geovetenskap med inriktning mot miljöanalys; Hydrology; hydrologi; mineralogi; petrologi och tektonik; Mineral Chemistry; Petrology and Tectonics;

   Sammanfattning : An integrated use of radio magnetotelluric (RMT) and controlled source tensor magnetotelluric (CSTMT) measurements, the so-called CSRMT method, has been employed in environmental and resource exploration studies. A number of case histories, including a groundwater investigation in glacial deposits, a study of fracture zones for geotechnical purposes and a mining exploration study of a copper deposit, are presented in this thesis in order to illustrate the usefulness and capability of the CSRMT method. LÄS MER

5. 4. Studies of sound generation and propagation in flow ducts

   Författare :Fabrice Ducret; Mats Åbom; Andy Moorhouse; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; two-port; plane wave; HVAC system; tailpipe; exhaust system; flexible duct; pipe; reflection coefficient; impedance; flow noise; vorticity; damping; scaling laws; impedance; transmission loss; perforated plate; slit; non linearity; Acoustics; Akustik;

   Sammanfattning : This thesis contains three papers investigating problems of interest for noise control in ducts. The first part of this thesis treats the sound propagation in rectangular ducts with flexible walls. Various experimental techniques are performed to measure the internal sound propagation and radiation to the surrounding. LÄS MER

7. 5. Strings as Sigma Models and in the Tensionless Limit

   Författare :Jonas Persson; Ulf Lindström; Joseph Minahan; Fawad Hassan; Uppsala universitet; []
   Nyckelord :Theoretical physics; Theoretical Physics; String Theory; Tensionless Strings; Supergravity Backgrounds; Plane Wave; Extended Supersymmetry; Non-Linear Sigma Models; Generalized Complex Geometry; T-duality; Teoretisk fysik;

   Sammanfattning : This thesis considers two different aspects of string theory, the tensionless limit of the string and supersymmetric sigma models with extended supersymmetry. First, the tensionless limit is used to find a IIB supergravity background generated by a tensionless string. The background has the characteristics of a gravitational shock-wave. LÄS MER