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Manway
A manhole (utility hole, maintenance hole, or sewer hole) is an opening to a confined space such as a shaft, utility vault, or large vessel. Manholes are often used as an access point for an underground public utility, allowing inspection, maintenance, and system upgrades. The majority of underground services have manholes, including water, sewers, telephone, electricity, storm drains, district heating, and gas. Manholes are generally found in urban areas, in streets and occasionally under sidewalks. In rural and undeveloped areas, services such as telephone and electricity are usually carried on utility poles or even pylons rather than underground. In Australia, ''manhole'' also commonly refers to an access hatch used to get access from a room or hallway into the ceiling cavity of a building. These manholes are typically around square. Construction Manhole closings are protected by a grating or manhole cover, a flat plug designed to prevent accidental or unauthori ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rural
In general, a rural area or a countryside is a geographic area that is located outside towns and cities. Typical rural areas have a low population density and small settlements. Agricultural areas and areas with forestry typically are described as rural. Different countries have varying definitions of ''rural'' for statistical and administrative purposes. In rural areas, because of their unique economic and social dynamics, and relationship to land-based industry such as agriculture, forestry and resource extraction, the economics are very different from cities and can be subject to boom and bust cycles and vulnerability to extreme weather or natural disasters, such as droughts. These dynamics alongside larger economic forces encouraging to urbanization have led to significant demographic declines, called rural flight, where economic incentives encourage younger populations to go to cities for education and access to jobs, leaving older, less educated and less wealthy populat ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sewer Gas
Sewer gas is a complex, generally obnoxious smelling mixture of toxic and nontoxic gases produced and collected in sewage systems by the decomposition of organic household or industrial wastes, typical components of sewage. Sewer gases may include hydrogen sulfide, ammonia, methane, esters, carbon monoxide, sulfur dioxide and nitrogen oxides. Improper disposal of petroleum products such as gasoline and mineral spirits contribute to sewer gas hazards. Sewer gases are of concern due to their odor, health effects, and potential for creating fire or explosions. In homes Sewer gas is typically restricted from entering buildings through plumbing traps that create a water seal at potential points of entry. In addition, plumbing vents allow sewer gases to be exhausted outdoors. Infrequently used plumbing fixtures may allow sewer gas to enter a home due to evaporation of water in the trap, especially in warm weather. The result is the most common means of sewer gas entering building ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydrogen Sulfide
Hydrogen sulfide is a chemical compound with the formula . It is a colorless chalcogen-hydride gas, and is poisonous, corrosive, and flammable, with trace amounts in ambient atmosphere having a characteristic foul odor of rotten eggs. The underground mine gas term for foul-smelling hydrogen sulfide-rich gas mixtures is ''stinkdamp''. Swedish chemist Carl Wilhelm Scheele is credited with having discovered the chemical composition of purified hydrogen sulfide in 1777. The British English spelling of this compound is hydrogen sulphide, a spelling no longer recommended by the Royal Society of Chemistry or the International Union of Pure and Applied Chemistry. Hydrogen sulfide is toxic to humans and most other animals by inhibiting cellular respiration in a manner similar to hydrogen cyanide. When it is inhaled or it or its salts are ingested in high amounts, damage to organs occurs rapidly with symptoms ranging from breathing difficulties to convulsions and death. Despite this, the ... [...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] |
Polypropylene
Polypropylene (PP), also known as polypropene, is a thermoplastic polymer used in a wide variety of applications. It is produced via chain-growth polymerization from the monomer propylene. Polypropylene belongs to the group of polyolefins and is partially crystalline and non-polar. Its properties are similar to polyethylene, but it is slightly harder and more heat-resistant. It is a white, mechanically rugged material and has a high chemical resistance. Bio-PP is the bio-based counterpart of polypropylene (PP). Polypropylene is the second-most widely produced commodity plastic (after polyethylene). In 2019, the global market for polypropylene was worth $126.03 billion. Revenues are expected to exceed US$145 billion by 2019. The sales of this material are forecast to grow at a rate of 5.8% per year until 2021. History Phillips Petroleum chemists J. Paul Hogan and Robert Banks first demonstrated the polymerization of propylene in 1951. The stereoselective polymerization t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Composite Material
A composite material (also called a composition material or shortened to composite, which is the common name) is a material which is produced from two or more constituent materials. These constituent materials have notably dissimilar chemical or physical properties and are merged to create a material with properties unlike the individual elements. Within the finished structure, the individual elements remain separate and distinct, distinguishing composites from mixtures and solid solutions. Typical engineered composite materials include: *Reinforced concrete and masonry *Composite wood such as plywood *Reinforced plastics, such as fibre-reinforced polymer or fiberglass *Ceramic matrix composites ( composite ceramic and metal matrices) *Metal matrix composites *and other advanced composite materials There are various reasons where new material can be favoured. Typical examples include materials which are less expensive, lighter, stronger or more durable when compared with commo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glass Reinforced Plastic
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 GFK ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Precast Concrete
Precast concrete is a construction product produced by casting concrete in a reusable molding (process), mold or "form" which is then cured in a controlled environment, transported to the construction site and maneuvered into place; examples include precast beam (structure), beams, and wall panels for tilt up construction. In contrast, cast-in-place concrete is poured into site-specific forms and cured on site. Recently lightweight expanded polystyrene foam is being used as the cores of precast wall panels, saving weight and increasing thermal insulation. Precast stone is distinguished from precast concrete by the finer construction aggregate, aggregate used in the mixture, so the result approaches the natural product. Overview Precast concrete is employed in both interior and exterior applications, from highway, bridge, and hi-rise projects to tilt-up building construction. By producing precast concrete in a controlled environment (typically referred to as a precast plant), ... [...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] |
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] |
Manhole Covers In Sidewalk (42839905802)
A manhole (utility hole, maintenance hole, or sewer hole) is an opening to a confined space such as a shaft, utility vault, or large vessel. Manholes are often used as an access point for an underground public utility, allowing inspection, maintenance, and system upgrades. The majority of underground services have manholes, including water, sewers, telephone, electricity, storm drains, district heating, and gas. Manholes are generally found in urban areas, in streets and occasionally under sidewalks. In rural and undeveloped areas, services such as telephone and electricity are usually carried on utility poles or even pylons rather than underground. In Australia, ''manhole'' also commonly refers to an access hatch used to get access from a room or hallway into the ceiling cavity of a building. These manholes are typically around square. Construction Manhole closings are protected by a grating or manhole cover, a flat plug designed to prevent accidental or unauthorize ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
