Public defense of the doctoral dissertation will be held on June 9th 2007 at 12 o'clock in auditorium D101 of the Department of Physical Sciences of the University of Helsinki, Finland.
VTT's MultiTrans programme enables modelling of radiation transport in arbitrary 3D geometry. The computational geometry is generated directly from a CAD-model, which makes it possible to use modern design tools. The computational grid is tree-structured and self-adaptive at the material boundaries, where the mesh automatically becomes the finest. With this method, even a complicated geometry can be represented in fine detail without an excessive number of grid points compared to equidistant mesh.
The tree-structure makes it possible to always find a coarser representation for the problem. This enables the use of multigrid method in iterative solution of the transport equation: the problem can be quickly solved on a much coarser grid, and this solution can then be used as an initial guess for the solution on finer grids. Multigrid method accelerates the iterative solution significantly. In addition, the tree structure leads to a smaller number of grid points, which also makes the iterative solution faster. To VTT's knowledge, this is the first application of the tree-multigrid technique to the radiation transport modelling.
The MultiTrans programme has been tested for different radiotherapy, such as boron neutron capture therapy (BNCT) given at VTT's nuclear research reactor, and for reactor physics applications. So far, the MultiTrans programme has been in use only at VTT.
When high accuracy is required, the simplified spherical harmonics approximation of the radiation transport used in MultiTrans has, in some cases, turned out to be problematic. More accurate methods will be studied further.
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Robots as Tools and Partners in Rehabilitation
17.08.2018 | Albert-Ludwigs-Universität Freiburg im Breisgau
Low bandwidth? Use more colors at once
17.08.2018 | Purdue University
New design tool automatically creates nanostructure 3D-print templates for user-given colors
Scientists present work at prestigious SIGGRAPH conference
Most of the objects we see are colored by pigments, but using pigments has disadvantages: such colors can fade, industrial pigments are often toxic, and...
Scientists at the University of California, Los Angeles present new research on a curious cosmic phenomenon known as "whistlers" -- very low frequency packets...
Scientists develop first tool to use machine learning methods to compute flow around interactively designable 3D objects. Tool will be presented at this year’s prestigious SIGGRAPH conference.
When engineers or designers want to test the aerodynamic properties of the newly designed shape of a car, airplane, or other object, they would normally model...
Researchers from TU Graz and their industry partners have unveiled a world first: the prototype of a robot-controlled, high-speed combined charging system (CCS) for electric vehicles that enables series charging of cars in various parking positions.
Global demand for electric vehicles is forecast to rise sharply: by 2025, the number of new vehicle registrations is expected to reach 25 million per year....
Proteins must be folded correctly to fulfill their molecular functions in cells. Molecular assistants called chaperones help proteins exploit their inbuilt folding potential and reach the correct three-dimensional structure. Researchers at the Max Planck Institute of Biochemistry (MPIB) have demonstrated that actin, the most abundant protein in higher developed cells, does not have the inbuilt potential to fold and instead requires special assistance to fold into its active state. The chaperone TRiC uses a previously undescribed mechanism to perform actin folding. The study was recently published in the journal Cell.
Actin is the most abundant protein in highly developed cells and has diverse functions in processes like cell stabilization, cell division and muscle...
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