Wiccan views of divinity the ancient Greek conception, where the elements correspond to matter (earth) and energy (fire), with the mediating elements (water, air) relating to the phases of matter (fire/earth mixtures). A more modern conception correlates the four elements to the four states of matter known to science: Solid (earth); Liquid (water); Gas (air); and Plasma (fire); with the akasha element corresponding to pure Energy. The Aristotelian system proposes a fifth or quintessential element, spirit (aether, akasha). The preferred version is a matter of ongoing dispute in the Wiccan community. There are other non-scientific conceptions, but they are not widely used among Wiccans.
Liquid-to-gas ratio for gas absorption this ratio gives an indication of the difficulty of removing a pollutant. Most wet scrubbers used for particulate control operate with liquid-to-gas ratios in the range of 4 to 20 gallons per 1,000 actual cubic foot (0.5 to 3 litres per actual cubic metre). Depending on scrubber design, a minimum volume of liquid is required to "wet" the scrubber internals and create sufficient collection targets. After a certain optimum point, adding excess liquid to a particulate wet scrubber does not increase efficiency and in fact, could be counter-productive by causing excessive pressure loss. Liquid-to-gas ratios for gas