Search for dissertations about: "natural attenuation"

Showing result 16 - 20 of 121 swedish dissertations containing the words natural attenuation.

  2. 16. Solute Transport Across Scales : Time Series Analyses of Water Quality Responses to Quantify Retention and Attenuation Mechanisms in Watersheds

    Author : Joakim Riml; Anders Wörman; Aaron I. Packman; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; Solute transport modeling; Transient storage; Tracer test; Central temporal moments; Spectral analysis; Parameterization;

    Abstract : The intra-continental movement of waterborne contaminants is governed by the distribution of solute load in the landscape along with the characteristics and distribution of the hydrological pathways that transport the solutes. An understanding of the processes affecting the transport and fate of the contaminants is crucial for assessments of solute concentrations and their environmental effect on downstream recipients. READ MORE

  4. 17. Lifetime Measurements of Excited States in the Semi-Magic Nucleus 94Ru

    Author : Aysegul Ertoprak; Bo Cederwall; Magdalena Zielinska; KTH; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; nuclear structure; lifetime measurements; doppler shift attenuation method; thick target; Fysik; Physics;

    Abstract : Lifetimes of highly excited states in the semi-magic (N=50) nucleus 94Ru were deduced from an analysis of the Doppler broadened transition line shapes. Excited states in 94Ru were populated in the 58Ni(40Ca, 4p)94Ru∗ fusion-evaporation reaction at the Grand Accélérateur National d’Ions Lourds (GANIL) accelerator complex situated in Caen, France. READ MORE

  5. 18. On the absolute and relative accuracy obtainable by some methods when predicting neutron and gamma ray attenuation and fast neutron spectrum in reactor shields

    Author : Erkki Aalto; Chalmers tekniska högskola; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; NATURVETENSKAP; NATURAL SCIENCES;

    Abstract : .... READ MORE

  6. 19. Extension of separately analytic functions and applications to mathematical tomography : characterizing the range of the exponential Radon transform

    Author : Ozan Öktem; Slawomir Kolodziej; Stockholms universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; matematik; Mathematics;

    Abstract : The principal problem that is dealt with in the thesis is to characterize the range of the exponential Radon transform for both constant attenuation and angle dependent attenuation (in the latter case we assume that the attenuation is a trigonometric polynomial). Such results are also of interest in applications such as ECT (Emission Computed Tomography). READ MORE

  7. 20. Magnetic resonance imaging with ultrashort echo time as a substitute for X-ray computed tomography

    Author : Adam Johansson; Tufve Nyholm; Karlsson Mikael; James Balter; Umeå universitet; []
    Keywords : NATURVETENSKAP; NATURAL SCIENCES; magnetic resonance imaging; computed tomography substitute; ultrashort echo time; parallel imaging; radial imaging; radiofysik; radiation physics;

    Abstract : Radiotherapy dose calculations have evolved from simple factor based methods performed with pen and paper, into computationally intensive simulations based on Monte Carlo theory and energy deposition kernel convolution.Similarly, in the field of positron emission tomography (PET), attenuation correction, which was originally omitted entirely, is now a crucial component of any PET reconstruction algorithm. READ MORE