pinhole test

pinhole test

1 a test performed on a person who has diminished visual acuity to distinguish a refractive error from organic disease. A refractive error may be corrected with glasses, whereas organic disease may signal the development of preventable blindness. Several pinholes, 0.5 to 2 mm in diameter, are punched in a card. The patient selects one and looks through it with one eye at a time, without wearing corrective lenses. If visual acuity is improved, the defect is refractive; if not, it is organic. The pinhole effect results from blocking peripheral light waves, which are most distorted by refractive error.
2 a test to determine the size of the focal spot of an x-ray tube.
3 a test to trace the path of x-ray tube movement.
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Pinhole test, the horizontal flow of water under hydraulic height of 50 mm diameter hole in the soil caused by a millimeter, starts [8].
Pinhole test results, all samples are in dark type are classified divergence.
Among the matters they consider are testing the amount of material in soil finer than number 200 (75 [micro]m) sieve, identifying and classifying dispersive clay soils by the pinhole test, preparing rock slabs for durability testing, analyzing the size of particles in natural and man-made riprap materials, determining the short-term compression behavior of turf reinforcement mats, measuring nominal thickness of permanent rolled erosion control products, installing articulating concrete block revetment systems, and determining the performance of a temporary ditch check in protecting earthen channels from stormwater-induced erosion.
For example, each HUGE Brand condom must pass an electronic pinhole test, as well as an electrolytic water leakage tests to ensure that each condom will bring the utmost in reliability and quality.