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Snowmelt System
A snowmelt system prevents the build-up of snow and ice on cycleways, walkways, patios and roadways, or more economically, only a portion of the area such as a pair of -wide tire tracks on a driveway or a center portion of a sidewalk, etc. It is also used to keep entire driveways and patios snow free in snow prone climates. The "snow melt" system is designed to function during a storm to improve safety and eliminate winter maintenance labor including shoveling, plowing snow and spreading de-icing salt or traction grit (sand). A snowmelt system may extend the life of the concrete, asphalt or under pavers by eliminating the use of Sodium chloride#Road salt, salts or other De-ice, de-icing chemicals, and physical damage from winter service vehicles. Many systems are fully automatic and require no human input to maintain a snow/ice-free horizontal surface. Systems are available in three broad types based on the heat source: electric resistance heat, heat from a conventional boiler ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Holland - Home Of The Heated Sidewalks
Holland is a geographical regionG. Geerts & H. Heestermans, 1981, ''Groot Woordenboek der Nederlandse Taal. Deel I'', Van Dale Lexicografie, Utrecht, p 1105 and former provinces of the Netherlands, province on the western coast of the Netherlands. From the 10th to the 16th century, Holland proper was a unified political region within the Holy Roman Empire as a county ruled by the counts of Holland. By the 17th century, the province of Holland had risen to become a maritime and economic power, dominating the other provinces of the newly independent Dutch Republic. The area of the former County of Holland roughly coincides with the two current Provinces of the Netherlands, Dutch provinces of North Holland and South Holland into which it was divided, and which together include the Netherlands' three largest cities: the Capital of the Netherlands, capital city (Amsterdam), the home of Port of Rotterdam, Europe's largest port (Rotterdam), and the seat of government (The Hague). Hollan ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propylene Glycol
Propylene glycol ( IUPAC name: propane-1,2-diol) is a viscous, colorless liquid. It is almost odorless and has a faintly sweet taste. Its chemical formula is CH3CH(OH)CH2OH. As it contains two alcohol groups, it is classified as a diol. An aliphatic diol may also be called a glycol. It is miscible with a broad range of solvents, including water, acetone, and chloroform. In general, glycols are non-irritating and have very low volatility. For certain uses as a food additive, propylene glycol is considered as GRAS by the US Food and Drug Administration, and is approved for food manufacturing. In the European Union, it has E-number E1520 for food applications. For cosmetics and pharmacology, the number is E490. Propylene glycol is also present in propylene glycol alginate, which is known as E405. Propylene glycol is approved and used as a vehicle for topical, oral, and some intravenous pharmaceutical preparations in the US and Europe. Structure The compound is sometimes ca ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
M4 Motorway
The M4, originally the London-South Wales Motorway, is the third longest motorway in the United Kingdom, running from west London to southwest Wales. The English section to the Severn Bridge was constructed between 1961 and 1971; the Welsh element was largely complete by 1980, though a non-motorway section around Briton Ferry bridge remained until 1993. On the opening of the Second Severn Crossing in 1996, the M4 was rerouted over it. The line of the motorway from London to Bristol runs closely in parallel with the A4 road (England), A4. After crossing the River Severn, toll-free since 17 December 2018, the motorway follows the A48 road (Great Britain), A48, to terminate at the Pont Abraham services in Carmarthenshire. The M4 is the only motorway in Wales apart from its two Spur route, spurs: the A48(M) motorway, A48(M) and the M48 motorway, M48. The major towns and cities along the routea distance of approximately include Slough, Reading, Berkshire, Reading, Swindon, Bristol, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Central Artery
The Central Artery (officially the John F. Fitzgerald Expressway) is the concurrent section of Interstate 93, US 1 and Route 3 through Downtown Boston, Massachusetts, United States. The modern-day Artery, built as part of the Big Dig from 1995 until 2003, begins at the Southeast Expressway in the South End. Traveling north, it has an interchange with the east–west Massachusetts Turnpike (I-90), and travels beneath the Financial District and Government Center through the O'Neill Tunnel. Route 3 exits onto the Leverett Connector within the tunnel in Charlestown; US 1 exits aboveground from the Zakim Bridge onto the Tobin Bridge, and I-93 continues on the Northern Expressway toward New Hampshire beyond the bridge. The original Artery, constructed in the 1950s, was named after John F. Fitzgerald; it was partly elevated and partly tunneled. Its reputation for congestion inspired the local nicknames "The Distressway," "the largest parking lot in the world", and "the ot ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Caulking
Caulk (also known as caulking and calking) is a material used to seal joints or seams against leakage in various structures and piping. The oldest form of caulk consisted of fibrous materials driven into the wedge-shaped seams between boards on wooden boats or ships. Cast iron sewerage pipes were formerly caulked in a similar way. Riveted seams in ships and boilers were formerly sealed by hammering the metal. Modern caulking compounds are flexible sealing compounds used to close up gaps in buildings and other structures against water, air, dust, insects, or as a component in firestopping. In the tunneling industry, caulking is the sealing of joints in segmental precast concrete tunnels, commonly by using concrete. Historical uses Wooden shipbuilding Traditional caulking (also spelled calking) on wooden vessels uses fibers of cotton and oakum (hemp) soaked in pine tar. These fibers are driven into the wedge-shaped seam between planks, with a caulking mallet and a broad ch ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trace Heating
Electric heat tracing, heat tape or surface heating, is a system used to maintain or raise the temperature of pipes and vessels using heat tracing cables. Trace heating takes the form of an electrical heating element run in physical contact along the length of a pipe. The pipe is usually covered with thermal insulation to retain heat losses from the pipe. Heat generated by the element then maintains the temperature of the pipe. Trace heating may be used to protect pipes from freezing, to maintain a constant flow temperature in hot water systems, or to maintain process temperatures for piping that must transport substances that solidify at ambient temperatures. Electric trace heating cables are an alternative to steam trace heating where steam is unavailable or unwanted.Paul R. Smith, ed. ''Facilities engineering and management handbook : commercial, industrial, and institutional buildings'', McGraw Hill, 2001 chapter 5 pages 5-198 through 5-201 Development Electric trace hea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Timer
A timer or countdown timer is a type of clock that starts from a specified time duration and stops upon reaching 00:00. It can also usually be stopped manually before the whole duration has elapsed. An example of a simple timer is an hourglass. Commonly, a timer triggers an alarm when it ends. A timer can be implemented through hardware or software. ''Stopwatches'' operate in the opposite direction, upwards from 00:00, measuring elapsed time since a given time instant. '' Time switches'' are timers that control an electric switch. Hardware Mechanical Mechanical timers use clockwork to measure time. Manual timers are typically set by turning a dial to the time interval desired, turning the dial stores energy in a mainspring to run the mechanism. They function similarly to a mechanical alarm clock, the energy in the mainspring causes a balance wheel to rotate back and forth. Each swing of the wheel releases the gear train to move forward by a small fixed amount, causing t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Society Of Heating, Refrigerating And Air-Conditioning Engineers
The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE ) is an American professional association seeking to advance heating, ventilation, air conditioning and refrigeration (HVAC&R) systems design and construction. ASHRAE has over 50,000 members in more than 130 countries worldwide. ASHRAE's members comprise building services engineers, architects, mechanical contractors, building owners, equipment manufacturers' employees, and others concerned with the design and construction of HVAC&R systems in buildings. The society funds research projects, offers continuing education programs, and develops and publishes technical standards to improve building services engineering, energy efficiency, indoor air quality, and sustainable development. History ASHRAE was founded in 1894 at a meeting of engineers in New York City, formerly headquartered at 345 East 47th Street (the United Engineering Center), and has held an annual meeting since 1895. Until ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Propane
Propane () is a three-carbon chain alkane with the molecular formula . It is a gas at standard temperature and pressure, but becomes liquid when compressed for transportation and storage. A by-product of natural gas processing and petroleum refining, it is often a constituent of liquefied petroleum gas (LPG), which is commonly used as a fuel in domestic and industrial applications and in low-emissions public transportation; other constituents of LPG may include propene, propylene, butane, butene, butylene, butadiene, and isobutylene. Discovered in 1857 by the French chemist Marcellin Berthelot, it became commercially available in the US by 1911. Propane has lower volumetric energy density than gasoline or coal, but has higher gravimetric energy density than them and burns more cleanly. Propane gas has become a popular choice for barbecues and portable stoves because its low −42 °C boiling point makes it vaporise inside pressurised liquid containers (it exists in two pha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Urban Heat Island
Urban areas usually experience the urban heat island (UHI) effect; that is, they are significantly warmer than surrounding rural areas. The temperature difference is usually larger at night than during the day, and is most apparent when winds are weak, under Block (meteorology), block conditions, noticeably during the summer and winter. The main cause of the UHI effect is from the modification of land surfaces, while waste heat generated by energy usage is a secondary contributor. Urban areas occupy about 0.5% of the Earth's land surface but host more than half of the world's population. As a population center grows, it tends to expand its area and increase its average temperature. The term heat island is also used; the term can be used to refer to any area that is relatively hotter than the surrounding, but generally refers to human-disturbed areas. Monthly precipitation (meteorology), rainfall is greater downwind of cities, partially due to the UHI. Increases in heat within urb ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bedrock
In geology, bedrock is solid rock that lies under loose material ( regolith) within the crust of Earth or another terrestrial planet. Definition Bedrock is the solid rock that underlies looser surface material. An exposed portion of bedrock is often called an outcrop. The various kinds of broken and weathered rock material, such as soil and subsoil, that may overlie the bedrock are known as regolith. Engineering geology The surface of the bedrock beneath the soil cover (regolith) is also known as ''rockhead'' in engineering geology, and its identification by digging, drilling or geophysical methods is an important task in most civil engineering projects. Superficial deposits can be very thick, such that the bedrock lies hundreds of meters below the surface. Weathering of bedrock Exposed bedrock experiences weathering, which may be physical or chemical, and which alters the structure of the rock to leave it susceptible to erosion. Bedrock may also experience subsur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rebar
Rebar (short for reinforcement bar or reinforcing bar), known when massed as reinforcing steel or steel reinforcement, is a tension device added to concrete to form ''reinforced concrete'' and reinforced masonry structures to strengthen and aid the concrete under tension. Concrete is strong under compression, but has low tensile strength. Rebar usually consists of steel bars which significantly increase the tensile strength of the structure. Rebar surfaces feature a continuous series of ribs, lugs or indentations to promote a better bond with the concrete and reduce the risk of slippage. The most common type of rebar is carbon steel, typically consisting of hot-rolled round bars with deformation patterns embossed into its surface. Steel and concrete have similar coefficients of thermal expansion, so a concrete structural member reinforced with steel will experience minimal differential stress as the temperature changes. Other readily available types of rebar are manufacture ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
