Hallux valgus is a common deformity of the big toe, defined as medial deflection of the first metatarsal bone along with lateral deflection of the first toe. Surgery has been shown to be b...
The influence of adverse pool water chemistry on the. vinyl was assessed through observation of changes in vinyl. colour, weight, dimensions, tensile strength and elongation. (stretching). The laboratory studies revealed that the factors most. affecting vinyl liners are high chlorine concentration, and.
The liner has five layers made of different kinds of materials: 1  The bottom layer next to the earth is made of at least two feet of clay that has been pounded until it is very compact. 2  Next is a layer of strong, flexible, very thick plastic, called high density polyethylene (HDPE).