Investigation of a compound concentrator with a quasi-parabolic guide

A compound concentrator guide has been investigated that provides uniform energy distribution over the receiver. The values of the focal parameters of the parabolas that form the quasi-parabolic guide curve have been determined. The parametric equations of the curve along which the parabolas foci travel have been set up. Arrangement variants of the guide curve branches have been considered, and the compound concentrators have been assessed.     

Explosion-Safe Pressure Sensors for Gathering and Transmitting Data at a Dispatcher Point Along a Radio Channel

The problems involved in developing explosion-safe sensors based on communicating vessels, placed at gas-regulator points, are considered.     

High-Sentivity vibration- and shock-resistant differential capacitive pressure transducer

The symmetrical construction of the force-transmission system of the transducer ensures high heat stability and vibration and shock resistance. A strip rocker arm resting on two small journals that operate under torsion as one piece with an external frame ensures high sensitivity, low hysteresis, and high measurement accuracy. Armenia. Translated from Izmeritel’naya Tekhnika, No. 12, pp. 39–41, December, 1999.     

Bacteriological Evaluation of Gingival Crevicular Fluid in Teeth Restored Using Fixed Dental Prostheses: An In Vivo Study

The present in vivo study determined the microbiological counts of the gingival crevicular fluid (GCF) among patients with fixed dental prostheses fabricated using three different techniques. A total of 129 subjects were divided into three study groups: first, cobalt-chrome-based, metal-ceramic prostheses fabricated by the conventional method (MC, n = 35); the second group consisted of cobalt-chrome-based, metal-ceramic prostheses fabricated by the computer-aided design and computer-aided manufacturing (CAD/CAM) technique (CC-MC, n = 35); the third group comprised zirconia-based ceramic prostheses fabricated using the CAD/CAM technique (CC-Zr, n = 35). The control consisted of 24 patients using prostheses fabricated with either MC, CC-MC, or CC-Zr. The GCF was obtained from the subjects before treatment, and 6 and 12 months after the prosthetic treatment. Bacteriological and bacterioscopic analysis of the GCF was performed to analyze the patients’ GCF. The data were analyzed using SPSS V20 (IBM Company, Chicago, IL, USA). The number of microorganisms of the gingival crevicular fluid in all groups at 12 months of prosthetic treatment reduced dramatically compared with the data obtained before prosthetic treatment. Inflammatory processes in the periodontium occurred slowly in the case of zirconium oxide-based ceramic constructions due to their biocompatibility with the mucous membranes and tissues of the oral cavity as well as a reduced risk of dental biofilm formation. This should be considered by dentists and prosthodontists when choosing restoration materials for subjects with periodontal pathology.     

Highly sensitive resonant piezoelectric pressure gage with a high load capacity

The load capacity of a new differential pressure gage that has been developed has been increased 24-fold by precompression of the piezoelectric elements. The system proposed for force transmission in the gage significantly increases the conversion factor. The gage is also more thermally stable than previous designs. The symmetry and monolithic construction of the force-transmitting system enhances the vibrational stability of the gage and alleviates hysteresis. Translated from Izmeritel'naya Tekhnika, No. 12, pp. 17–19, December, 1997.     

Tangent systems for cone angle measurement

Translated from Izmeritel'naya Tekhnika, No. 3, p. 72, March, 1992.     

On the concentrating capability of a circular cylindrical reflector

The concentration field of a circular cylindrical reflector is examined in accordance with the laws of geometric optics. The limits of the energy concentration zone that are defined by the envelopes of the reflected rays are shown. The parametric equations of the characteristic curve that coincides with the envelope are obtained. A technique for selecting the parameters of the circular cylindrical reflector based on the average magnitude of the energy concentration and the receiving strip width is presented. The location of the receiver in the reflector concentration field is justified.     

Role of renewable energy sources in developing the energy sector of the Republic of Armenia

The main directions and ways of power engineering development in the Republic of Armenia are examined.