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Grating
A grating is any regularly spaced collection of essentially identical, parallel, elongated elements. Gratings usually consist of a single set of elongated elements, but can consist of two sets, in which case the second set is usually perpendicular to the first (as illustrated). When the two sets are perpendicular, this is also known as a wikt:grid (as in grid paper) or a mesh. As filters A grating covering a drain (as illustrated) can be a collection of iron bars (the identical, elongated elements) held together (to ensure the bars are parallel and regularly spaced) by a lighter iron frame. Gratings over drains and air vents are used as filters, to block movement of large solids (e.g. people) and to allow movement of liquids. A register is a type of grating used in heating, ventilation, and air conditioning, which transmits air, while stopping solid objects. File:Vindobona Hoher Markt-71.JPG, Grating - drain cover, ancient Roman architecture at Vindobona, Austria. File:Montr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
FRP Grating
Fiberglass reinforced plastic grating (also known as FRP grating, glass reinforced plastic grating or fiberglass grating) is a composite material manufactured by combining a matrix of resin and fiberglass. Fiberglass grating does not corrode like steel grating and is therefore used in corrosive environments to reduce maintenance costs. It is used in a variety of applications including walkways and overhead platforms. FRP grating is a structural product that can be weight-bearing between spans. Types Molded FRP grating is composed of alternating directional layers of continuous glass fiber for strength, with resin to consolidate the fibers and provide the shape and corrosion-resistance. Due to its bidirectional strength, molded grating can tolerate cutouts in the panel to allow pipe or equipment penetrations without requiring additional support around the opening. Molded grating has very high impact tolerance, as well as the highest chemical resistance of any fiberglass grating. It ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Anti-slip Grating
Anti-slip steel grating (also known as slip-resistant grating) is a type of bar grating designed to prevent slippage. Steel bar grating is manufactured in a variety of methods. Welded bar grating consists of load bars electrically fuse welded to cross bars. Pressure-locked bar grating, or swaged grating, is where steel rods are forced through and locked in load bars. Riveted bar grating is where the load bars are riveted to the cross bars. There are wide varieties of trade names for each type manufactured. Perforated sheet metal types: * Diamond-shaped serrated perforated sheet metal. Examples of trade names are Grip Strut, Diamond Grip, Ry, Diamond, Grip Span, Deck Span, Grip Track. * Round hole perforated sheet metal. Examples of trade names are Perf-o-grip, Safety-grip, Shur Grip, Ry-Grip, Open Grip and Grate Lock. * Raised dimple perforated sheet metal Sheet metal is metal formed into thin, flat pieces, usually by an industrial process. Sheet metal is one of the fundam ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spatial Frequency
In mathematics, physics, and engineering, spatial frequency is a characteristic of any structure that is periodic across position in space. The spatial frequency is a measure of how often sinusoidal components (as determined by the Fourier transform) of the structure repeat per unit of distance. The SI unit of spatial frequency is cycles per meter (m). In image-processing applications, spatial frequency is often expressed in units of cycles per millimeter (mm) or equivalently line pairs per mm. In wave propagation, the spatial frequency is also known as ''wavenumber''. Ordinary wavenumber is defined as the reciprocal of wavelength \lambda and is commonly denoted by \xi or sometimes \nu: :\xi = \frac. Angular wavenumber k, expressed in rad per m, is related to ordinary wavenumber and wavelength by :k = 2 \pi \xi = \frac. Visual perception In the study of visual perception, sinusoidal gratings are frequently used to probe the capabilities of the visual system. In these stimu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Deck (bridge)
A deck is the surface of a bridge. A structural element of its Superstructure#bridge, superstructure, it may be constructed of concrete, steel, grating, open grating, or wood. Sometimes the deck is covered by a track ballast, railroad bed and railroad track, track, asphalt concrete, or other form of pavement (material), pavement for ease of vehicle crossing. A concrete deck may be an integral part of the bridge structure (T-beam or double tee structure) or it may be supported with I-beams or steel girders. When a bridge deck is installed in a through truss, it is sometimes called a floor system. A suspended bridge deck will be suspended from the main structural elements on a suspension or arch bridge. On some bridges, such as a Tied-arch bridge, tied-arch or a Cable-stayed bridge, cable-stayed, the deck is a primary structural element, carrying tension or compression to support the span. A deck bridge is one in which the deck itself is the main structural element, itself carr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Drain (plumbing)
A drain is the primary vessel or conduit for unwanted water or waste liquids to be flumed away, either to a more useful area, funnelled into a receptacle, or run into sewers or stormwater mains as waste discharge to be released or processed. Design, installation and maintenance Drain design and installation parameters are engineered to ensure drain functionality for its intended purpose, allowing for variances in volume, matter to be conveyed and maintenance requirements. Drain installation takes into account principles related to gravity, vacuum, grade, human exposure safety to biological agents and resistance to functional failure. Also incorporated in drain design are requirements for drain maintenance and repair of a blocked drain. Safety Waste versus re-circulated drains In most systems the drain is for discharge of waste fluids, such as the drain in a sink in which the water is drained when it is no longer needed. In the United Kingdom, plumbers refer to waste water ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fiberglass
Fiberglass (American English) or fibreglass (Commonwealth English) is a common type of fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened into a sheet called a chopped strand mat, or woven into glass cloth. The plastic matrix may be a thermoset polymer matrix—most often based on thermosetting polymers such as epoxy, polyester resin, or vinyl ester resin—or a thermoplastic. Cheaper and more flexible than carbon fiber, it is stronger than many metals by weight, non- magnetic, non-conductive, transparent to electromagnetic radiation, can be molded into complex shapes, and is chemically inert under many circumstances. Applications include aircraft, boats, automobiles, bath tubs and enclosures, swimming pools, hot tubs, septic tanks, water tanks, roofing, pipes, cladding, orthopedic casts, surfboards, and external door skins. Other common names for fiberglass are glass-reinforced plastic (GRP), glass-fiber reinforced plastic (GFRP) or GF ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Heating, Ventilation, And Air Conditioning
Heating, ventilation, and air conditioning (HVAC) is the use of various technologies to control the temperature, humidity, and purity of the air in an enclosed space. Its goal is to provide thermal comfort and acceptable indoor air quality. HVAC system design is a subdiscipline of mechanical engineering, based on the principles of thermodynamics, fluid mechanics, and heat transfer. "Refrigeration" is sometimes added to the field's abbreviation as HVAC&R or HVACR, or "ventilation" is dropped, as in HACR (as in the designation of HACR-rated circuit breakers). HVAC is an important part of residential structures such as single family homes, apartment buildings, hotels, and senior living facilities; medium to large industrial and office buildings such as skyscrapers and hospitals; vehicles such as cars, trains, airplanes, ships and submarines; and in marine environments, where safe and healthy building conditions are regulated with respect to temperature and humidity, using fresh ai ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Manhole Cover
A manhole cover or maintenance hole cover is a removable plate forming the lid over the opening of a manhole, an opening large enough for a person to pass through that is used as an access point for an underground vault or pipe. It is designed to prevent anyone or anything from falling in, and to keep out unauthorized persons and material. Manhole covers date back at least to the era of ancient Rome, which had sewer grates made from stone. Description Manhole covers are often made out of cast iron, concrete or a combination of the two. This makes them inexpensive, strong, and heavy, usually weighing more than . The weight helps to keep them in place when traffic passes over them, and makes it difficult for unauthorized people without suitable tools to remove them. Manhole covers may also be made from glass-reinforced plastic or other composite material (especially in Europe, or where cover theft is of concern). Because of law restricting acceptable manual handling weights, Eu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reflectance
The reflectance of the surface of a material is its effectiveness in reflecting radiant energy. It is the fraction of incident electromagnetic power that is reflected at the boundary. Reflectance is a component of the response of the electronic structure of the material to the electromagnetic field of light, and is in general a function of the frequency, or wavelength, of the light, its polarization, and the angle of incidence. The dependence of reflectance on the wavelength is called a ''reflectance spectrum'' or ''spectral reflectance curve''. Mathematical definitions Hemispherical reflectance The ''hemispherical reflectance'' of a surface, denoted , is defined as R = \frac, where is the radiant flux ''reflected'' by that surface and is the radiant flux ''received'' by that surface. Spectral hemispherical reflectance The ''spectral hemispherical reflectance in frequency'' and ''spectral hemispherical reflectance in wavelength'' of a surface, denoted and respectively, are ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Steel
Steel is an alloy made up of iron with added carbon to improve its strength and fracture resistance compared to other forms of iron. Many other elements may be present or added. Stainless steels that are corrosion- and oxidation-resistant typically need an additional 11% chromium. Because of its high tensile strength and low cost, steel is used in buildings, infrastructure, tools, ships, trains, cars, machines, electrical appliances, weapons, and rockets. Iron is the base metal of steel. Depending on the temperature, it can take two crystalline forms (allotropic forms): body-centred cubic and face-centred cubic. The interaction of the allotropes of iron with the alloying elements, primarily carbon, gives steel and cast iron their range of unique properties. In pure iron, the crystal structure has relatively little resistance to the iron atoms slipping past one another, and so pure iron is quite ductile, or soft and easily formed. In steel, small amounts of carbon, other ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium
Aluminium (aluminum in American and Canadian English) is a chemical element with the symbol Al and atomic number 13. Aluminium has a density lower than those of other common metals, at approximately one third that of steel. It has a great affinity towards oxygen, and forms a protective layer of oxide on the surface when exposed to air. Aluminium visually resembles silver, both in its color and in its great ability to reflect light. It is soft, non-magnetic and ductile. It has one stable isotope, 27Al; this isotope is very common, making aluminium the twelfth most common element in the Universe. The radioactivity of 26Al is used in radiodating. Chemically, aluminium is a post-transition metal in the boron group; as is common for the group, aluminium forms compounds primarily in the +3 oxidation state. The aluminium cation Al3+ is small and highly charged; as such, it is polarizing, and bonds aluminium forms tend towards covalency. The strong affinity tow ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
