Conductivity, electrical earths atmosphere

Modern ceramic materials now include zirconium oxide (Zr02), titanium carbide (TiC), and silicon nitride (SiN). There are now many more uses of these new ceramic materials. For example, vehicle components such as ceramic bearings do not need lubrication - even at high speeds. In space technology, ceramic tiles protected the Space Shuttle from intense heat during its re-entry into the Earth s atmosphere. In the power supply industry, they are used as insulators due to the fact that they do not conduct electricity (Figure 3.39). 

A general method of avoiding an accumulation of static electricity incorporating substances conducting electricity into the explosive on condition that the manufacturing apparatus is earthed. Relatively high humidity of the atmosphere (wherever it is not harmful to the production (8J, ionization of the atmosphere by irradiation with 7- or X-rays are other factors which help in avoiding the accumulation of static electricity [9]. 

Early models used a value for that remained constant throughout the day. However, measurements show that the deposition velocity increases during the day as surface heating increases atmospheric turbulence and hence diffusion, and plant stomatal activity increases (50—52). More recent models take this variation of into account. In one approach, the first step is to estimate the upper limit for in terms of the transport processes alone. This value is then modified to account for surface interaction, because the earth s surface is not a perfect sink for all pollutants. This method has led to what is referred to as the resistance model (52,53) that represents as the analogue of an electrical conductance... 

After Julius Elster and Hans Geitel had noticed that the electrical conductivity of the air in caves and closed cellars is higher than that in the free atmosphere, they finally found that this was caused by the presence of emanations, or radioactive gases, in the ground. In a series of investigations from 1901 to 1906 they demonstrated the presence of radioactive elements in various kinds of rocks and soils, and showed that minute amounts of both radium and thorium are widely distributed in the earth s crust, in spring waters, in sea water, and in the atmosphere (85, 96). 

Rare earth metal RE-doped SrTiOsCRE = Nd, Pr, and La) in forms of Sr i.zRE Ti i.zTi Os showed good electrical conductivity after being reduced at high temperatures in the H2 atmosphere, but exhibited low corrosion resistance in a 50% H2SO4 solution at 353 K, due to the formation of SrS04. 

Care must be taken to earth drums of flammable liquid when filling them and to use electrically conductive hoses. Filling plastic jugs and other non-conductive vessels such as glass bottles should, if it has to be done, be performed very slowly to allow the static charge to leak to the atmosphere. 

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