COMPARATIVE ASSESSMENT OF BACTERIAL PERMEABILITY OF A PERSONAL PROTECTIVE RESPIRATORY EQUIPMENT AT DIFFERENT DURATIONS OF ITS CONTINUOUS OPERATION.

OBJECTIVE: The aim: To establish the level of antibacterial protection of the studied personal protective respiratory equipment set and its main components and compare antibacterial resistance of the personal protective respiratory equipment set in the presence and absence of filtering components. PATIENTS AND METHODS: Materials and methods: The proposed methodology for assessing biological protection parameters is based on testing the permeability of personal respiratory protection equipment for bacteria by the method of serial dilutions. Also additional culturing of separate components of the protective set on a separate media is carried out. The experiment was also repeated in the absence of filtering elements and when they were replaced by gauze masks. RESULTS: Results: The use of a fully equipped pneumatic helmet counteracted the penetration of the bacterial aerosol, which was manifested in the absence of growth on the media. The results obtained with the full configuration, as well as the indicators of the spread of bacteria when removing the filter elements and replacing them with gauze masks, showed that the device creates sufficient positive air pressure inside. The latter becomes a restraining factor that does not allow microorganisms to penetrate through the lower circuit. CONCLUSION: Conclusions: Increasing the duration of continuous operation of the conceptual model up to 24 hours, increasing the bacterial load on the filters do not lead to a deterioration in the properties of antibacterial protection. Bacterial aerosol did not penetrate into the inner space of pneumatic helmet.

Theory of repeating nucleation in point contact reactions between nanowires.

Modification of the classical Zeldovich nucleation theory for nonstationary conditions is presented. It is applied to the recently discovered repeating nucleation events in point contact reactions between metal and silicon nanowires to form epitaxial silicides; the nucleation provides the reproducible quasi-stationary conditions satisfying the fundamental suppositions of the modified theory. The modified theory enables us to predict the rate of repeating nucleation at nanoscale level by developing a theory of the incubation time. The understanding is extremely important for the design and applications of nanoheterostructures.