An analysis of new generation coal gasification projects

The global trends of increasing oil and gas costs have compelled coal possessing countries to start long term underground coal gasification (UCG) projects. These enhance national energy security and are among the cleanest, ecologically safest coal utilization technologies. This paper delineates the major characteristics of such technologies and analyzes technical solutions. Highlighting the desire to develop large scale industrial UCG plants, pilot level projects are presented using a new UCG method developed in Russia by Joint Stock Company Gazprom Promgaz. This method is distinct for its high controllability, stability, and energy efficiency. New, efficient technical solutions have been developed over the last 10–15 years and are patented in Russia. They guarantee controllability and stability of UCG gas production. Over one hundred injection and gas production wells have been operated simultaneously.     

The analysis of solar UVB radiation as a function of solar global radiation,ozone layer thickness and aerosol optical density

Incident solar radiation (insolation) is attenuated by two different phenomena, (i) atmospheric scattering by air molecules, water vapor and aerosols, and (ii) atmospheric absorption by ozone, water and carbon dioxide. The degree of terrestrial solar radiation attenuation is a function of its optical path length, i.e., the distance the Sun’s ray traverse through the Earth’s atmosphere prior to being incident on the its surface. The attenuation by atmospheric scattering, irrespective of source, is an inverse function of the wavelength. Absorption of insolation in the atmosphere is due mainly to ozone in the ultraviolet range and water vapor in the infrared range of the solar spectrum. Ozone absorption decreases with increasing wavelength and above 350 nm there is no absorption. Thus, a priori, any changes in either the ozone layer thickness (OLT) and/or aerosol optical density (AOD) will have a greater effect on ultraviolet radiation, in general, and on UVB in particular. An empirical correlation that determines the UVB radiation intensity as a function of solar global radiation, OLT, AOD and optical path length as represented by the air mass is presented and validated by an independent database. In addition, a parameter sensitivity study was performed on the empirical correlation using two different methods. The application of the empirical correlation as a function of hour type (i.e., clear, partially cloudy and cloudy) was also investigated.     

One-sided error probabilistic inductive inference and reliable frequency identification

Fox EX- and BC-type identification, one-sided error probabilistic inference and reliable frequency identification on sets of functions are introduced. In particular, we relate the one to the other and characterize one-sided error probabilistic inference to exactly coincide with reliable frequency identification, on any setM. Moreover, we show that reliable EX and BC-frequency inference forms a new discrete hierarchy having the breakpoints 1,1/2, 1/3 ,….     

Slab-based Faraday isolators and Faraday mirrors for 10-kW average laser power

It is shown that the use of slabs instead of rods makes it possible to fabricate Faraday isolators and Faraday mirrors operating at a multikilowatt power. Analytical dependences of thermally induced depolarization in Faraday devices on radiation power and on slab aspect ratio have been obtained.