Saudi Arabia experiences a large need for water supplies to provide continued growth, development and industrialization all
over the country. It is aimed to have desalting water replace natural water resources, which are quite few and diminishing, for municipal and industrial use. By the recent advances in membrane ·technology, desalination of sea water by reverse osmosis is a practical and economical method of providing fresn water in Saudi Arabia. Reve~se osmosis was only used to provide potable water to small dis~ersed communities as well as individuals.

Thermionic emission from Pt filaments is increased by a factor of 1000 in a flow of hydrocarbons at - 1 Torr pressure and space-charge-free conditions. The effect can be used to trace the initial stages of hydrocarbon decomposition and carbon deposition, and it has possible application as an automobile exhaust sensor or a gas chromatograph detector.

In order to document the microfacies and diagenesis of the reefal limestone in the uppermost part of the
Callovian Tuwaiq Mountain Limestone Formation at Khashm Al-Qaddiyah area, central Saudi Arabia,
scleractinian corals and rock samples were collected and thin sections were prepared. Coral framestone,
coral floatstone, pelloidal packstone, bioclastic packstone, bioclastic wacke/packstone, algal wackestone
and bioclastic foraminiferal wacke/packstone were the recorded microfacies types. Cementation,