Sökning: "Attenuation"

Visar resultat 31 - 35 av 409 avhandlingar innehållade ordet Attenuation.

  1. 31. Ultrasound Contrast Agents Loaded with Magnetic Nanoparticles : Acoustic and Mechanical Characterization

    Författare :VeeraVenkata Satyanarayana Kothapalli; Lars-Åke Brodin; Jan Engvall; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Ultrasound contrast agents; SPION nanoparticles; harmonic oscillation; backscattering power; attenuation coefficient; phase velocity; nonlinear equation of motion;

    Sammanfattning : The current methodologies in body scanning diagnostic uses different simultaneous imaging modalities like Ultrasound (US), magnetic resonance imaging (MRI), single photon emission tomography (SPECT) and positron emission tomography (PET). The field requires combination of different modalities for effective use in clinical diagnostics. LÄS MER

  3. 32. Laser Sheet Imaging and Image Analysis for Combustion Research

    Författare :Rafeef Abu-Gharbieh; Chalmers tekniska högskola; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; non-linear diffusion filtering; optically dense sprays; curve evolution propagation; image sequence analysis; laser induced fluorescence; geodesic paths; level sets; LIF; optical density; spray characterization; flame propagation; laser; particle image velocimetry; spectroscopy; combustion engines; spray diagnostics; Mie scattering; flame fronts; laser attenuation; tracking; combustion diagnostics; curve matching; combustion; laser sheet imaging; PIV; time resolved imaging; segmentation;

    Sammanfattning : This Thesis presents techniques that aim at exploiting the potential of image analysis and processing in order to solve problems of data reduction, interpolation, quantification, and interpretation within the field of experimental laser imaging of combustion processes. Combustion is the most important source of energy for power generation, heating, and transportation in the world today and its strong dominance is projected to continue in the foreseeable future. LÄS MER

  4. 33. Radioluminescence : A simple model for fluorescent layers

    Författare :Jan Lindström; Eva Lund; Michael Sandborg; Gudrun Alm-Carlsson; Linköpings universitet; []
    Nyckelord :Extrinsic efficiency; extinction factor; radioluminescence; modelling; Monte Carlo; optical attenuation; optimisation; particle size; phosphor; scintillator; MEDICINE; MEDICIN;

    Sammanfattning : The aim of this thesis is to present a simple model for the radiation to light conversion processes in fluorescent layers as an aid in future developments and applications. Optimisation between sensitivity and spatial resolution for fluorescent layers in digital radiology is a delicate task where the extrinsic efficiency for various phosphors needs to be established for varying parameters. LÄS MER

  5. 34. Fluxes and Mixing Processes in the Marine Atmospheric Boundary Layer

    Författare :Erik Olof Nilsson; Anna Rutgersson; Harm Jonker; Uppsala universitet; []
    Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES; Waves; Growing sea; Swell; Marine boundary layer; Air-sea interaction; Mixing; Momentum flux; Wind stress; Flux attenuation; Sensor separation; Large eddy simulation; Multiresolution analysis; Coupling; Wave model; Climate model; Wave age; Meteorology; Meteorologi;

    Sammanfattning : Atmospheric models are strongly dependent on the turbulent exchange of momentum, sensible heat and moisture (latent heat) at the surface. Oceans cover about 70% of the Earth’s surface and understanding the processes that control air-sea exchange is of great importance in order to predict weather and climate. LÄS MER

  7. 35. Techniques for Localization of Insulation Degradation along Medium-Voltage Power Cables

    Författare :Ruslan Papazyan; Roland Eriksson; Fred Steennis; KTH; []
    Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Electrical power technology; Attenuation measurement; cross-linked polyethylene insulation; discontinuities; localization; mass-impregnated insulation; numerical analysis; parameter estimation; power cable metallic screen; scattering parameters; time domain reflectometry; velocity measurements; water treeing; Elkraftteknik; Electric power engineering; Elkraftteknik;

    Sammanfattning : Time Domain Reflectometry (TDR) has been used for localization of transmission line discontinuities in diverse applications. Various challenges have to be addressed when applying TDR for localization of insulation degradation in power cables. LÄS MER