Ultratonotherapy in the combined treatment of chronic periodontitis

The trial of apex-locator application for improvement of endodontic management of root canals of a tooth as well as of ultratonotherapy in 120 patients aged 20-40 years with chronic granulomatous and granulating periodontitis has proved that ultratonotherapy relieves inflammation and stimulates regeneration of bone tissue.     

Failure of structures due to crack growth and damage

Crack growth and damage in viscoelastic bodies are studied. Using the Sih criterion of fracture the safe and critical loads as well as delaytime of rupture for structure with a crack are determined. Damage is studied on the base of the energy approach. Evolution of damage, the threshold stress, delay time and limiting damage and strain in a rod under action of a constant load are found.     

Breakdown of an organically based composite material in a high-temperature gas flow

The authors analyze a mechanism for breakdown of a composite material of the textolite type, composed of the chemical elements H, C, N, and O in an air stream of stagnation enthalpy 14,000–73,000 kJ/kg. A comparison of the theory and the experimental data show that the accuracy of the theoretical model is 25%.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 50, No. 3, pp. 367—373, March, 1986.