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Lightning Rod
A lightning rod or lightning conductor (British English) is a metal rod mounted on a structure and intended to protect the structure from a lightning strike. If lightning hits the structure, it will preferentially strike the rod and be conducted to ground through a wire, instead of passing through the structure, where it could start a fire or cause electrocution. Lightning rods are also called finials, air terminals, or strike termination devices. In a lightning protection system, a lightning rod is a single component of the system. The lightning rod requires a connection to earth to perform its protective function. Lightning rods come in many different forms, including hollow, solid, pointed, rounded, flat strips, or even bristle brush-like. The main attribute common to all lightning rods is that they are all made of conductive materials, such as copper and aluminum. Copper and its alloys are the most common materials used in lightning protection. History The principle of t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Wood
Wood is a porous and fibrous structural tissue found in the stems and roots of trees and other woody plants. It is an organic materiala natural composite of cellulose fibers that are strong in tension and embedded in a matrix of lignin that resists compression. Wood is sometimes defined as only the secondary xylem in the stems of trees, or it is defined more broadly to include the same type of tissue elsewhere such as in the roots of trees or shrubs. In a living tree it performs a support function, enabling woody plants to grow large or to stand up by themselves. It also conveys water and nutrients between the leaves, other growing tissues, and the roots. Wood may also refer to other plant materials with comparable properties, and to material engineered from wood, or woodchips or fiber. Wood has been used for thousands of years for fuel, as a construction material, for making tools and weapons, furniture and paper. More recently it emerged as a feedstock for the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Premonstratensian
The Order of Canons Regular of Prémontré (), also known as the Premonstratensians, the Norbertines and, in Britain and Ireland, as the White Canons (from the colour of their habit), is a religious order of canons regular of the Catholic Church founded in Prémontré near Laon in 1120 by Norbert of Xanten, who later became Archbishop of Magdeburg. Premonstratensians are designated by ''OPraem'' (''Ordo Praemonstratensis'') following their name. Norbert was a friend of Bernard of Clairvaux and was largely influenced by the Cistercian ideals as to both the manner of life and the government of his order. As the Premonstratensians are not monks but canons regular, their work often involves preaching and the exercising of pastoral ministry; they frequently serve in parishes close to their abbeys or priories. History The order was founded in 1120. Saint Norbert had made various efforts to introduce a strict form of canonical life in various communities of canons in Germany; in 112 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Akinfiy Demidov
Akinfiy Nikitich Demidov (russian: Акинфий Никитич Демидов) (1678 Tula - 5 August 1745 Yatskoye Ustye, Menzelinsky Uyezd, Orenburg Governorate) was a Russian industrialist of the Demidov family. Life He was the eldest son of Nikita Demidov and increased the family fortune, raising it to one of Russia's most important industrial dynasties. He studied the secrets of metallurgical production in Saxony. He zealously set to work and became the creator of the "empire" of the Demidovs, which by the middle of the 18th century produced 52% of all Russian metal. He set up at least nine steel foundries and munitions factories from 1717 to 1735, and had 25 by his death. He also created iron and copper mines in the Urals and Western Siberia to supply them and mines for precious and semi-precious stones, silver and gold. In 1720, having bought from Nikolai Fedorovich Golovin an estate in the Barminskaya volost of the Nizhny Novgorod district, the Demidovs received a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rebar
Rebar (short for reinforcing bar), known when massed as reinforcing steel or reinforcement steel, is a steel bar used as a tension device in reinforced concrete and reinforced masonry structures to strengthen and aid the concrete under tension. Concrete is strong under compression, but has weak tensile strength. Rebar significantly increases the tensile strength of the structure. Rebar's surface features 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 manufactured of stainless steel, and composite bars made of glass fiber, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ground (electricity)
In electrical engineering, ground or earth is a reference point in an electrical circuit from which voltages are measured, a common return path for electric current, or a direct physical connection to the Earth. Electrical circuits may be connected to ground for several reasons. Exposed conductive parts of electrical equipment are connected to ground, to protect users from electrical shock hazard. If internal insulation fails, dangerous voltages may appear on the exposed conductive parts. Connecting exposed parts to ground will allow circuit breakers (or RCDs) to interrupt power supply in the event of a fault. In electric power distribution systems, a protective earth (PE) conductor is an essential part of the safety provided by the earthing system. Connection to ground also limits the build-up of static electricity when handling flammable products or electrostatic-sensitive devices. In some telegraph and power transmission circuits, the ground itself can be used as one ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gilding
Gilding is a decorative technique for applying a very thin coating of gold over solid surfaces such as metal (most common), wood, porcelain, or stone. A gilded object is also described as "gilt". Where metal is gilded, the metal below was traditionally silver in the West, to make silver-gilt (or ''vermeil'') objects, but gilt-bronze is commonly used in China, and also called ormolu if it is Western. Methods of gilding include hand application and gluing, typically of gold leaf, chemical gilding, and electroplating, the last also called gold plating. Parcel-gilt (partial gilt) objects are only gilded over part of their surfaces. This may mean that all of the inside, and none of the outside, of a chalice or similar vessel is gilded, or that patterns or images are made up by using a combination of gilt and ungilted areas. Gilding gives an object a gold appearance at a fraction of the cost of creating a solid gold object. In addition, a solid gold piece would often be too sof ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spire
A spire is a tall, slender, pointed structure on top of a roof of a building or tower, especially at the summit of church steeples. A spire may have a square, circular, or polygonal plan, with a roughly conical or pyramidal shape. Spires are typically made of stonework or brickwork, or else of timber structures with metal cladding, ceramic tiling, roof shingles, or slates on the exterior. Since towers supporting spires are usually square, square-plan spires emerge directly from the tower's walls, but octagonal spires are either built for a pyramidal transition section called a ''broach'' at the spire's base, or else freed spaces around the tower's summit for decorative elements like pinnacles. The former solution is known as a ''broach spire''. Small or short spires are known as ''spikes'', ''spirelets'', or '' flèches''. Etymology This sense of the word spire is attested in English since the 1590s, ''spir'' having been used in Middle Low German since the 14th centu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leaning Tower Of Nevyansk
The Leaning Tower of Nevyansk (russian: Невья́нская ба́шня) is a tower in the town of Nevyansk in Sverdlovsk Oblast, Russia, built in the 18th century. Its construction was funded by Peter the Great's associate Akinfiy Demidov, a famous Russian manufacturer and son of industrialist Nikita Demidov. The height of the tower is from the ground and the base is . The deviation of the top part of the tower from vertical is about 3 degrees. The exact date of construction is unknown, but Russian historians believe that it was built between 1721 and 1745. There is no information about the architect of this edifice. Technical parameters of the tower *The base is a square with sides of 9.5 metres. *Deviation of the tower from the vertical is about 1.85 metres. *Secular sediment is 0.9 millimetres per year. *The height is 57.5 metres. *The thickness of the walls is 2 metres at the base, 32 centimetres at the top level. *The weathercock weighs 25 kilograms and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Explosion
An explosion is a rapid expansion in volume associated with an extreme outward release of energy, usually with the generation of high temperatures and release of high-pressure gases. Supersonic explosions created by high explosives are known as detonations and travel through shock waves. Subsonic explosions are created by low explosives through a slower combustion process known as deflagration. Causes Explosions can occur in nature due to a large influx of energy. Most natural explosions arise from volcanic or stellar processes of various sorts. Explosive volcanic eruptions occur when magma rises from below, it has very dissolved gas in it. The reduction of pressure as the magma rises and causes the gas to bubble out of solution, resulting in a rapid increase in volume. Explosions also occur as a result of impact events and in phenomena such as hydrothermal explosions (also due to volcanic processes). Explosions can also occur outside of Earth in the universe in events su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Structure Fire
A structure fire is a fire involving the structural components of various types of residential, commercial or industrial buildings, such as barn fires. Residential buildings range from single-family detached homes and townhouses to apartments and tower blocks, or various commercial buildings ranging from offices to shopping malls. This is in contrast to "room and contents" fires, chimney fires, vehicle fires, wildfires or other outdoor fires. Structure fires typically have a similar response from the fire department that include engines, ladder trucks, rescue squads, chief officers, and an EMS unit, each of which will have specific initial assignments. The actual response and assignments will vary between fire departments. It is not unusual for some fire departments to have a pre-determined mobilization plan for when a fire incident is reported in certain structures in their area. This plan may include mobilizing the nearest aerial firefighting vehicle to a tower block, o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Voltage
Voltage, also known as electric pressure, electric tension, or (electric) potential difference, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to move a test charge between the two points. In the International System of Units, the derived unit for voltage is named '' volt''. The voltage between points can be caused by the build-up of electric charge (e.g., a capacitor), and from an electromotive force (e.g., electromagnetic induction in generator, inductors, and transformers). On a macroscopic scale, a potential difference can be caused by electrochemical processes (e.g., cells and batteries), the pressure-induced piezoelectric effect, and the thermoelectric effect. A voltmeter can be used to measure the voltage between two points in a system. Often a common reference potential such as the ground of the system is used as one of the points. A voltage can represent either a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
