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Tetrapods used to protect a seawall Large interlocked Xblocs (8.0 m 3 or 280 cu ft) in a trial placement. A wave-dissipating concrete block is a naturally or manually interlocking concrete structure designed and employed to minimize the effects of wave action upon shores and shoreline structures, such as quays and jetties.
A pinhole occluder is an opaque disk with one or more small holes through it, used by ophthalmologists, orthoptists and optometrists to test visual acuity. The occluder is a simple way to focus light, as in a pinhole camera, temporarily removing the effects of refractive errors such as myopia. Because light passes only through the center of the ...
A dolos (plural: dolosse [1]: 10 ) is a wave-dissipating concrete block used in great numbers as a form of coastal management. It is a type of tetrapod . Weighing up to 8 tonnes (8.8 short tons ), dolosse are used to build revetments for protection against the erosive force of waves from a body of water.
Ecology blocks are manufactured using concrete left over from other construction processes. A cross-section of an eco-block typically measures 2 feet (61 cm) square, with block lengths ranging from 3 feet (91 cm) to 6 feet (180 cm). One block weighs between 1,800 pounds (820 kg) and 4,000 pounds (1,800 kg). [1]
A pallet of "8-inch" concrete blocks An interior wall of painted concrete blocks Concrete masonry blocks A building constructed with concrete masonry blocks. A concrete block, also known as a cinder block in North American English, breeze block in British English, or concrete masonry unit (CMU), or by various other terms, is a standard-size rectangular block used in building construction.
Large Xblocs (8.0 m 3 or 280 cu ft) on a trial placement area. An Xbloc is a wave-dissipating concrete block (or "armour unit") designed to protect shores, harbour walls, seawalls, breakwaters and other coastal structures from the direct impact of incoming waves.
Pinhole glasses, also known as stenopeic glasses, are eyeglasses with a series of pinhole-sized perforations filling an opaque sheet of plastic in place of each lens. Similar to the workings of a pinhole camera , each perforation allows only a very narrow beam of light to enter the eye which reduces the size of the circle of confusion on the ...
A bughole (or pinhole) is a small hole in the surface of a concrete structure caused by the expansion and eventual outgassing of trapped pockets of air in setting concrete. [ 1 ] [ 2 ] [ 3 ] Bugholes are undesirable, as they may compromise the structural integrity of concrete emplacements.