national environmental protection organization will address the meeting of the national working group on air pollution reduction. at the meeting of the national coordination and management headquarters of the country's watersheds , chaired by the first vice president , approved the comprehensive plan for the management of the salt lake of qom. preventing the drying up of the salt lake, reducing the pollution load, and sustainable protection and exploitation are the three main axes of this project. in this meeting, the guidelines for determining privacy. the ecology of wetlands was also determined. specialists of a knowledge -based group managed to design and internalize the surface and density measurement system of the gamma meter. this product is used in industries such as steel and petrochemical . gamma density and surface measurement system is a technological product, the result of the efforts of specialists of a group the basic knowledge of this equipment has two applications , one is dam measurement, and the other is density measurement of liquids inside pipes, which are used, for example, in mining and st