Scanning image simulations

To evaluate the VIGRAL method, we scanned steel blocks with simulated flaws using a Flexilrak and a upi-50 instrument. This system allows for rapid and accurate acquisition of the desired data, including the A-scan, B-scan, and C-scan data, and serves to evaluate, offline, the V-scan image (Figure 8). 

Camera and scanned images often show color that at a distance looks acceptable, yet the color mixing occurs at a pixel level. Dithering uses several colors to simulate a single color. At a distance this is not an issue, but if the file is to be printed as a large format, it can become very noticeable. 

Turnbull DH, Foster FS (1992) Simulation of B-scan images from two-dimensional transducer arrays Part H-com-parisons between linear and two-dimensional phased arrays. Ultrason Imaging 14 344-353... 

Fig. 9. Scanning election microscope image of the typical fly ash particles. The samples were taken in a simulated experiment, 130 minutes after generation of the fly ash aerosol (Photo Courtesy Teinemaa el al. 2002) ( Elsevier).

For the detailed study of reaction-transport interactions in the porous catalytic layer, the spatially 3D model computer-reconstructed washcoat section can be employed (Koci et al., 2006, 2007a). The structure of porous catalyst support is controlled in the course of washcoat preparation on two levels (i) the level of macropores, influenced by mixing of wet supporting material particles with different sizes followed by specific thermal treatment and (ii) the level of meso-/ micropores, determined by the internal nanostructure of the used materials (e.g. alumina, zeolites) and sizes of noble metal crystallites. Information about the porous structure (pore size distribution, typical sizes of particles, etc.) on the micro- and nanoscale levels can be obtained from scanning electron microscopy (SEM), transmission electron microscopy ( ), or other high-resolution imaging techniques in combination with mercury porosimetry and BET adsorption isotherm data. This information can be used in computer reconstruction of porous catalytic medium. In the reconstructed catalyst, transport (diffusion, permeation, heat conduction) and combined reaction-transport processes can be simulated on detailed level (Kosek et al., 2005). 

Fig. 11. Adsorption of acetylene on Si(OOl). The experimental STM scans show three different adsorption configurations, labeled I-III (A). They are due to the possibility of restructuring of the carbon bond to either a double bond (configurations (1) and (2) in frame (B)), or to a single bond (configurations (3) and (4)) in frame (B)). The resulting STM images (frame (C)) in the simulation agree quite well with three of the configurations found in the experiments ((A), features I, II, and III). The experimental images were taken from [58].

Scanning tunneling microscopy of solid films of Cm and C > clearly demonstrate the occurrence of photochemical polymerization of these fullerenes in the solid state. X-ray diffraction studies show that such a polymerization is accompanied by contraction of the unit-cell volume in the case of Cm and expansion in the case of C70. This is also evidenced from the STM images. These observations help to understand the differences in the amotphization behavior of Cm and C70 under pressure. Amorphization of Cm under pressure is irreversible because it is accompanied by polymerization associated with a contraction of the unit cel volume. Monte Carlo simulations show how pressure-induced polymerization is favored in Cm because of proper orientation as well as the required proximity of the molecules. Amorphization of C70, on the other hand, is reversible because Cn is less compressible and polymerization is not favored under pressure. 

The technique is widely used in the diagnosis of cancers, brain tumours, hydrocephalus and multiple sclerosis. It was reported in New Scientist4 that very small (4 mm) breast cancers can be detected by measuring the diffraction pattern given off by them. Figure 11.8 is a simulation of the type of image obtained from a MRI scan for a patient with multiple sclerosis. 

Loren, N., Hagslatt, H., Nyden, M., and Hermansson, A.M. (2005). Water mobility in heterogeneous emulsions determined by a new eombination of confocal laser scanning microscopy, image analysis, NMR diflusometry and finite element method simulation. J. Chem. Phys. 122, 024716... 

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