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A megawatt-class space power installation based on a mirror solar radiation collector and an magnetohydrodynamic (MHD) generator is considered. Probable decisions for the construction of a mirror system and a radiation heat receiver are proposed. The analysis of mass characteristics shows that the level of specific power of 600 W/kg can be reached. An MHD generator with nonuniform gas-plasma flow, being the most suitable type of this type of device for the space use, is examined with respect to questions of nonequilibrium plasma kinetics, efficiency of energy conversion, and two-dimensional (2-D) instability of flow. It is shown that the two-dimensional structure of plasma layer remains stable during the time of fly through the MHD channel due to turbulent viscosity. Two-dimensional effects do not cause a significant decrease of energy conversion efficiency, which makes the considered scheme usable in space energy installations. Index Terms--Energy conversion, MHD generator, solar collector, space power station.

Experimentally determined scalar flux density spectra are presented for 1.37 and 2.75 MeV photons emitted by an Na-24 uniform disc source penetrating shields of six two-layer combinations. Also, the experimental facility is described. The benchmark data for photon energy 1.37 and 2.75 MeV fill a gap in the energy range of practical interest and provide useful reference values for computational method evaluation.

Presents an ultrasonic rangefinding technique that improves accuracy when used as an edge scanner. Relative phase angle between continuously transmitted and received signals; Use of continuous emission waves; Variation in transmitted frequency.

In recent times a great deal of interest has been shown the computer vision and robotics research community within the remote (non-contact) determination of configurations by using direct (active) range finding. The presently developed range finder is based upon the use of laser light and triangulation and aims at long distance high precision measurements. New image processing techniques are combined with high efficiency electronics in order to provide reliable distance information. Furthermore, a method is introduced in order to overcome the inherent 'missing parts' problem when the system is used as a profile scanner (second scan method). Such a system could form part of a 3D-robot vision system providing depth and obstacle avoidance information. [ABSTRACT FROM AUTHOR]

Introduces the design of a digital ultrasonic scanning system for positioning underwater remotely operated vehicles. Principle of operation; Construction of three-dimension image of the environment surrounding the vehicle; Advantages of the system.