Human eye The upper end of the range is given in terms of normal visual performance as 10 cd/m (100,000,000 or one hundred million candelas per square meter). The eye includes a lens similar to lenses found in optical instruments such as cameras and the same physics principles can be applied. The pupil of the human eye is its aperture; the iris is the diaphragm that serves as the aperture stop. Refraction in the cornea causes the effective aperture (the entrance pupil) to differ slightly from the physical pupil diameter. The entrance pupil is typically about 4 mm in diameter, although it
Diaphragm pump be constructed for low pressure sensitivity. With the right material consideration, diaphragms can seal over a wide range of pressures and temperatures without needing lubrication or maintenance. Diaphragm pump characteristics: Small mechanically activated diaphragm pumps are also used as air compressors and as a source of low-grade vacuum. Compared to other compressors, these pumps are quiet, cheap and, most importantly, have no moving parts in the airstream. This allows them to be used without added lubrication in contact with the air, so the compressed air produced can be guaranteed clean. Diaphragm pump A diaphragm pump (also known as a Membrane