Search results
Results from the WOW.Com Content Network
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 .
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.
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.
A concrete slab is a common structural element of modern buildings, consisting of a flat, horizontal surface made of cast concrete. Steel- reinforced slabs, typically between 100 and 500 mm thick, are most often used to construct floors and ceilings, while thinner mud slabs may be used for exterior paving ( see below ).
A set of yellow truncated domes on the down-ramp in a parking lot. Tactile paving (also called tenji blocks, truncated domes, detectable warnings, tactile tiles, tactile ground surface indicators, tactile walking surface indicators, or detectable warning surfaces) is a system of textured ground surface indicators found at roadsides (such as at curb cuts), by and on stairs, and on railway ...
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.
A compressed earth block (CEB), also known as a pressed earth block or a compressed soil block, is a building material made primarily from an appropriate mix of fairly dry inorganic subsoil, non-expansive clay, sand, and aggregate. Forming compressed earth blocks requires dampening, mechanically pressing at high pressure, and then drying the ...
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 ...