STUDIES OF THE PEGTYMEL PETROGLYPHS, BASED ON A COMPLEX OF NATURAL-SCIENTIFIC METHODS IN THE NATIONAL RESEARCH CENTRE “KURCHATOV INSTITUTE”

В НИЦ Курчатовский институт с использованием комплекса естественнонаучных методов исследован камень с выбитыми изображениями, найденный на р. Пегтымель на Чукотке археологической экспедицией ИА РАН под руководством Е.Г.Дэвлет. Установлены состав и природа минеральных образований на поверхности камня с петроглифами. Выявлен скальный загар , содержащий марганец и потенциально пригодный для датирования. На карте распределения химических элементов в выбивке зафиксированы медь и цинк и предположено их антропогенное происхождение в качестве микрочастиц древнего орудия. Намечена возможная дата создания петроглифов: конец II начало I тыс. до н.э. Подтверждена версия исследователей петроглифов Пегтымеля о том, что рисунки на скалах выбивались металлическими орудиями. Several separated stone blocks with pecked images had been found in the course of the expedition for study the rock art site at the Pegtymel River in the western part of the Chukotka Peninsula. The expedition (2005 2008) was organized by the Institute of Archaeology and lead by Ekaterina Devlet. One of such blocks was taken away from the site to Moscow, which made it possible to carry out recently its study in the Kurchatov Institute with the use of a whole complex of natural-scientific methods. The researchers have identified mineral compounds on the surface of the decorated rock and determined the rock varnish formation on it. Cu Zn particles have been detected in the pecked area. It is possible that the particles were introduced as a result of processing the rock with bronze or brass tool. The date of creation the petroglyphs is proposed as the end of the 2nd beginning of the 1st millennium BC.

Managing Varnish of Turbine Oil

Varnish now becomes the severe problem of gas turbine, nuclear power plant and other industry which use lubricant oil and hydraulic fluid. The cause of varnish formation is heat, oxidation and contamination. Varnish can cause many turbine problems. The Membrane Patch Colorimetry (MPC) test can be used to measure varnish. Partial or all oil change, Filtration with Cellulose Media and System Chemical Cleaning can be applied to mitigate varnish.

Filtration of Gas Turbine Lube Fluid Using Anti-Static Filters

Requirement for higher turbine performance and lower costs has resulted in smaller lubrication and control fluid systems operating at higher cleanliness levels, thus requiring higher fluid flux and finer filtration levels. Triboelectric Charge (TEC) generation by fine filters and its eventual discharge is considered to be a source of lubricating fluid breakdown and the resulting formation of resinous byproducts. These fluid breakdown byproducts form deposits or ‘varnish’ on the metallic surfaces causing servo-valve stiction along with other adverse consequences. TEC generation occurs in fluid systems as a result of friction between the fluid and mainly the filtration media fibers. The friction causes charge separation between the filtration medium and the fluid, with the fluid oppositely charged to the filtration medium. The magnitude of charge generated depends on many interrelated factors, including the nature of the filter material and the fluid, fluid velocity, viscosity, conductivity and the contact area. The electrostatic discharge manifests itself in several ways, the most easily noticeable way being an audible clicking noise as the discharge of the accumulated electrostatic charge causes sparking internally within the system. In addition to lubricant degradation and varnish formation, the electrical charge can travel downstream with the fluid causing damage to system components, including the filter. There have been reports of heat exchanger damage, located downstream of the filters, due to the electrostatic charging of the fluid. The use of metal support meshes or other methods to dissipate the electrostatic charge to prevent its build-up in the filter cartridge may prevent the discharge within the filter assembly and the resulting filter damage, but it does not prevent the charging of the fluid, and the migration of the charge downstream causing damage to the fluid and the downstream components. In 2005 Pall Corporation introduced filter cartridges that mitigate charge generation and dissipate the small charge generated at its inception, thus offering the advantage of eliminating filter damage entirely, and significantly reducing the migration of the charge into the fluid and its associated damage to the fluid and the resulting varnish formation. This paper discusses the experience with the electrostatic charge dissipating filtration for the gas turbine lubrication application.