Pressure membranes and

Most of the concentrate is returned to the sea, but some plants process it further to produce salt. Since the recovery by RO is often less than 50%, salt production is not often combined with RO. With the development of higher-pressure membranes and increasing restrictions on effluent, this combination may become more important in the future [19]. 

Vessels of noncircular cross section may be subjected to external pressure Membrane and bending stresses are considered the same as for internal pressure unless the resulting stresses are compressive where stability may be a possible mode of failure. Interaction equations are used to examine die various plates for stability. Calculated stresses are compared with critical buckling stresses with ii factor of safety applied. This is described in Article 13-14 of the ASME Code,... 

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