Laser-based generation

A variation of the sintering or melting process in the powder bed is the laser-based generation with the powder nozzle. The powder is, parallel to the laser beam, added in and then melted. The processes are suitable for larger layer thicknesses and are preferably used for repair purposes. 

Laser-based profilometry systems have also been adapted for unique applications in nuclear power generating plants. Applications where quantitative information with regard to surface condition for mechanisms such as surface pitting and flow-assisted corrosion are candidates for this NDT method. 

Recently, in situ studies of catalytic surface chemical reactions at high pressures have been undertaken [46, 47]. These studies employed sum frequency generation (SFG) and STM in order to probe the surfaces as the reactions are occurring under conditions similar to those employed for industrial catalysis (SFG is a laser-based teclmique that is described in section A 1.7.5.5 and section BT22). These studies have shown that the highly stable adsorbate sites that are probed under vacuum conditions are not necessarily tlie same sites that are active in high-pressure catalysis. Instead, less stable sites that are only occupied at high pressures are often responsible for catalysis. Because the active... 

The same equipment, which is used for time-resolved Ivuninescence application is suitable for other laser-based spectroscopies. Thus several spectroscopic methods may be applied simultaneously. The most important techniques, which may be used together with time-resolved luminescence, are laser-induced breakdown spectroscopy, Raman spectroscopy and Second Harmonics Generation spectroscopy. 

The possibilities of time-resolved laser based spectroscopies have been demonstrated, combining such techniques as luminescence, Raman, breakdown and second-harmonic generation. Radiometric sorting of minerals using LIBS was patented and apparatus for evaluation of phosphate rocks with elevated dolomite content has been developed and constructed. 

The Applications of Laser-induced Time-resolved Spectroscopic Techniques chapter starts with a short description of laser-induced spectroscopies, which may be used in combination with laser-induced luminescence, namely Breakdown, Raman and Second Harmonic Generation. The chapter contains several examples of the application of laser-based spectroscopies in remote sensing and radiometric sorting of minerals. The proljlem of minerals as geomaterials for radioactive waste storage is also considered. 

These advances have opened new fields of relativity-related research in two complementary directions. One is related to the advent of laser-based sources of coherent radiation in the X-UV domain, either from high harmonic generation [6], [7] or from X-ray-laser devices, [8], The imple-... 

The most recent US-based measurement methodologies are based on laser sources and are of two general types, namely (a) all-laser approaches, where both US generation and detection are laser based and (b) half-laser approaches, where laser light is used either for generation or detection of US, but not both. 

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