Effect of porosity on the statistical amplitude distribution of backscattered ultrasonic pulses in particulate reinforced metal-matrix composites.

This work aims at studying the effect of porosity in particulate reinforced metal-matrix composites on the statistical amplitude distribution of backscattered laser-induced ultrasonic pulses in these composites. A special laser-ultrasonic transducer used in experiments combines laser excitation and piezoelectric detection of broadband ultrasonic pulses in composite specimens with only one plane surface available for laser irradiation. We studied stir cast hypereutectic aluminium-silicon alloy A336 matrix composites reinforced with the SiC micro particles (volume fractions of 0.

Laser-ultrasonic nondestructive evaluation of porosity in particulate reinforced metal-matrix composites.

In this work, we propose the laser-ultrasonic method for nondestructive evaluation of porosity in particulate reinforced metal-matrix composites fabricated by stir and in-situ reactive casting techniques. The method is based on the influence of porosity on dispersion of the phase velocity of longitudinal acoustic waves, which is measured by the broadband acoustic spectroscopy with laser excitation of ultrasound (laser-ultrasonic spectroscopy). We studied stir cast hypereutectic aluminum-silicon alloy A336 matrix composites reinforced with the SiC micro particles (3.

[Hygienic evaluation of the methods of water conditioning on marine ships].

Results of test stands and of field studies (on marine ships) have shown, that the use of installations for water preparation (IWP), including mineralizers of the wash out type and ozonizers, makes it possible to get water of stable quality independent of the terms of operations of the installations, and also provides the possibility of conditioning of shore water supply and of carrying out disinfection of the ship water supply system. Comparative analysis of the operation of various kinds of IWP on marine ships testifies to the necessity of development of the new types of IWP, which will promote health preservation of crew members having difficult long independent voyages.