Soil mechanics necessary to run water through the sieves to wash the coarse particles and clods through. A variety of sieve sizes are available. The boundary between sand and silt is arbitrary. According to the Unified Soil Classification System, a #4 sieve (4 openings per inch) having 4.75mm opening size separates sand from gravel and a #200 sieve with an 0.075 mm opening separates sand from silt and clay. According to the British standard, 0.063 mm is the boundary between sand and silt, and 2 mm is the boundary between sand and gravel. The classification of fine-grained soils, i.e., soils that are
Granular corneal dystrophy Granular corneal dystrophy Granular corneal dystrophy is a slowly progressive corneal dystrophy that most often begins in early childhood. Granular corneal dystrophy has two types: Granular corneal dystrophy is diagnosed during an eye examination by an ophthalmologist or optometrist. The lesions consist of central, fine, whitish granular lesions in the cornea. Visual acuity is slightly reduced. Granular corneal dystrophy is caused by a mutation in the TGFBI gene, located on chromosome 5q31. The disorder is inherited in an autosomal dominant manner. This indicates that the defective gene responsible for the disorder is located on an autosome (chromosome 5 is an