Sökning: "beam model"

Visar resultat 6 - 10 av 422 avhandlingar innehållade orden beam model.

1. 6. Micro-Flow Reactors for Kinetic Studies of Model Catalysts made by Electron-Beam Lithography

   Författare :Stefan Johansson; Chalmers tekniska högskola; []
   Nyckelord :NATURVETENSKAP; NATURAL SCIENCES; bistability; catalysis; nano-fabrication; supported model catalyst; CO oxidation; electron-beam lithography EBL ; micro-reactor;

   Sammanfattning : The main objective of this work is to explore the potential of using electron beam lithography (EBL) to prepare well defined supported model catalysts, which can be used for catalytic research. The work has involved three major areas (i) EBL-fabrication of catalysts, (ii) design of a micro-flow reactor for catalytic evaluation, and (iii) problem oriented research using EBL-fabricated model catalysts. LÄS MER

3. 7. Mixed Beam Dosimetry - From Reactor Core to BNCT Patient

   Författare :Per Munck af Rosenschöld; Lund Medicinsk strålningsfysik; []
   Nyckelord :MEDICIN OCH HÄLSOVETENSKAP; MEDICAL AND HEALTH SCIENCES; BNCT; dosimetry; radiotherapy; mixed beam; quality assurance; in vivo dosimetry; Monte Carlo; ionization chamber; foil activation; MCNP; beam quality correction factor; photon transmission.; Nukleärmedicin; radiobiology; Nuclear medicine; radiobiologi; Radiofarmaceutisk teknik; Radiopharmaceutical technology;

   Sammanfattning : Accurate radiation dosimetry is of paramount importance in order to ensure safe delivery of radiotherapy, and for the possibility of meaningful evaluation of clinical trials, as the radiation absorbed dose is correlated to tissue response. The aim of the studies described in this thesis was to investigate and devise novel approaches to mixed beam dosimetry in boron neutron capture therapy (BNCT). LÄS MER

4. 8. Beam-to-Beam Contact and Its Application to Micromechanical Simulation of Fiber Networks

   Författare :Hamid Reza Motamedian; Artem Kulachenko; Umberto Perego; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; fiber network; beam-to-beam contact; rotational contact; non-consistent; simulation; finite element; multiscale; microscale; micromechanics; paper; refining; beating; fine; hygroexpansion; shrinkage; drying; Hållfasthetslära; Solid Mechanics;

   Sammanfattning : This doctoral thesis covers the topic of modeling the three-dimensional fiber net- works with the finite element method. It contains the part addressing the numerical aspects of the modeling, namely, the contact formulation and application of the developed methods to the fundamental questions such as the effect of randomness in fiber properties and effect of fines and hygroexpansion. LÄS MER

5. 9. Propagation of some coherent and partially coherent laser beams

   Författare :Yangjian Cai; Sailing He; Franco Gori; KTH; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; : dark hollow beam; elliptical Gaussian beam; flat-topped beam; twisted anisotropic Gaussian Schell-model; partial coherent; propagation; paraxial optical system; Electrical engineering; electronics and photonics; Elektroteknik; elektronik och fotonik;

   Sammanfattning : In this thesis, we investigate the propagation of some coherent and partially coherent laser beams, including a dark hollow beam (DHB), an elliptical Gaussian beam (EGB), a flat-topped beam and a twisted anisotropic Gaussian Schell-model (TAGSM) beam, through a paraxial optical system or a turbulent atmosphere. Several theoretical models are proposed to describe a DHB of circular or non-circular symmetry. LÄS MER

7. 10. Investigation of Melt Pool Thermo-hydrodynamic Behaviour inLaser Beam Welding ofTi-6Al-4V through Numerical Simulation

   Författare :Seyyed Mohammad Ali Noori Rahim Abadi; Isabelle Choquet; Fredrik Sikström; Högskolan Väst; []
   Nyckelord :TEKNIK OCH TEKNOLOGIER; ENGINEERING AND TECHNOLOGY; Laser beam welding; Beam shaping; Absorptivity; Conductionmode welding; Free surface deformation; Computational Fluid Dynamics; OpenFOAM.; Strålformning; Absorptivitet; Värmeledningssvetsning; Ytdeformation; Computational Fluid Dynamics; OpenFOAM.; Production Technology; Produktionsteknik;

   Sammanfattning : Laser is an efficient and widely used heat source in metal processing suchas welding and additive manufacturing. It has some great advantages compared to the other conventional heat sources like electron beam and arc namely: ability of handling complicated joint geometries and producing large components. LÄS MER