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  1. Tainan - Wikipedia

    en.wikipedia.org › wiki › Tainan

    Tainan, officially Tainan City, is a special municipality in southern Taiwan facing the Taiwan Strait on its western coast. Tainan is the oldest city on the island and also commonly known as the "Capital City" for its over 200 years of ...

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  2. Spain - Wikipedia

    en.wikipedia.org › wiki › Spain

    Spain is a secular parliamentary democracy and a constitutional monarchy, with King Felipe VI as head of state. It is a highly developed country and a high income country, with the world's fourteenth-largest economy by nominal GDP and the ...

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  3. COVID-19 - Wikipedia

    en.wikipedia.org › wiki › Covid-19

    The disease is mainly transmitted via the respiratory route when people inhale droplets and small airborne particles (that form an aerosol) that infected people breath out as they breathe, talk, cough, sneeze, or sing.[49] [50] [51] Infected ...

  4. Russia - Wikipedia

    en.wikipedia.org › wiki › Russia

    Russia (Russian: Россия, Rossiya, Russian pronunciation: [rɐˈsʲijə]), or the Russian Federation, [b] is a country spanning Eastern Europe and Northern Asia.It is the largest country in the world by area, covering over 17 million square ...

  5. Turkey - Wikipedia

    en.wikipedia.org › wiki › Turkey

    Turkey (Turkish: Türkiye [ˈtyɾcije]), officially the Republic of Turkey, [a] is a transcontinental country located mainly on the peninsula of Anatolia in Western Asia, with a smaller portion on East Thrace in Southeast Europe.It shares borders ...

  6. Ukraine - Wikipedia

    en.wikipedia.org › wiki › Ukraine

    Ukraine is a large country in Eastern Europe, lying mostly in the East European Plain. It is the second-largest European country, after Russia. It covers an area of 603,628 square kilometres (233,062 sq mi) and with a coastline of 2,782 ...

  7. Mother's Day - Wikipedia

    en.wikipedia.org › wiki › Mother&

    Mother's Day is a celebration honoring the mother of the family or individual, as well as motherhood, maternal bonds, and the influence of mothers in society.It is celebrated on different days in many parts of the world, most commonly in the ...

  8. Bungee jumping - Wikipedia

    en.wikipedia.org › wiki › Bungee_jumping
    • History
    • Equipment
    • The Highest Jump
    • Variations
    • Risk of Injury
    • in Popular Culture
    • Further Reading
    • External Links

    Early tethered jumping

    The land diving (Sa: Gol) of Pentecost Island in Vanuatu is an ancient ritual in which young men jump from tall wooden platforms with vines tied to their ankles as a test of their courage and passage into manhood. Unlike in modern bungee-jumping, land-divers intentionally hit the ground, but the vines absorb sufficient force to make the impact non-lethal. The land-diving ritual on Pentecost has been claimed as an inspiration by AJ Hackett, prompting calls from the islanders' representatives f...

    Etymology

    The word "bungee" originates from West Country dialect of the English language, meaning "Anything thick and squat", as defined by James Jennings in his book "Observations of Some of the Dialects in The West of England" published 1825. In 1928, the word started to be used for a rubber eraser. The Oxford English Dictionary records early use of the phrase in 1938 relating to launching of glidersusing an elasticated cord, and also as "A long nylon-cased rubber band used for securing luggage". "Bu...

    Modern sport

    The first modern bungee jumps were made on 1 April 1979 from the 250-foot (76 m) Clifton Suspension Bridge in Bristol, England, by David Kirke, and Simon Keeling, members of the Oxford University Dangerous Sports Club, and Geoff Tabin, a professional climber who tied the ropes for the jump. The students had come up with the idea after discussing a "vine jumping" ritual carried out by certain residents of Vanuatu. The jumpers were arrested shortly after, but continued with jumps in the US from...

    The elastic rope first used in bungee jumping, and still used by many commercial operators, is factory-produced braided shock cord. This special bungee cord consists of many latex strands enclosed in a tough outer cover. The outer cover may be applied when the latex is pre-stressed, so that the cord's resistance to extension is already significant at the cord's natural length. This gives a harder, sharper bounce. The braided cover also provides significant durability benefits. Other operators, including A. J. Hackett and most southern-hemisphereoperators, use unbraided cords with exposed latex strands. These give a softer, longer bounce and can be home-produced. Accidents where participants became detached led many commercial operators to use a body harness, if only as a backup for an ankle attachment. Body harnesses generally derive from climbing equipment rather than parachute equipment.

    In August 2005, AJ Hackett added a SkyJump to the Macau Tower, making it the world's highest jump at 233 metres (764 ft). The SkyJump did not qualify as the world's highest bungeeas it is not strictly speaking a bungee jump, but instead what is referred to as a 'Decelerator-Descent' jump, using a steel cable and decelerator system, rather than an elastic rope. On 17 December 2006, the Macau Tower started operating a proper bungee jump, which became the "Highest Commercial Bungee Jump in the World" according to the Guinness Book of Records. The Macau Tower Bungy has a "Guide cable" system that limits swing (the jump is very close to the structure of the tower itself) but does not have any effect on the speed of descent, so this still qualifies the jump for the World Record. Another commercial bungee jump currently in operation is just 13m smaller, at 220 metres (720 ft). This jump, made without guide ropes, is from the top of the Verzasca Dam near Locarno, Switzerland. It appears in...

    Catapult

    In "Catapult" (Reverse Bungee or Bungee Rocket), the jumper starts on the ground.The jumper is secured and the cord is stretched, then released and shooting the jumper up into the air. This is often achieved using either a crane or a hoist attached to a (semi-)perma structure. This simplifies the action of stretching the cord and later lowering the participant to the ground.

    Trampoline

    "Bungy Trampoline" uses elements from bungy and trampolining. The participant begins on a trampoline and is fitted into a body harness, which is attached via bungy cords to two high poles on either side of the trampoline. As they begin to jump, the bungy cords are tightened, allowing a higher jump than could normally be made from a trampolinealone.

    Running

    "Bungee Running" involves no jumping as such. It merely consists of, as the name suggests, running along a track (often inflatable) with a bungee cord attached. One often has a velcro-backed marker that marks how far the runner got before the bungee cord pulled back. This activity can often be found at fairs and carnivals and is often most popular with children.

    Bungee jumping injuries may be divided into those that occur after jumping secondary to equipment mishap or tragic accident, and those that occur regardless of safety measures. In the first instance, injury can happen if the safety harness fails, the cord length is miscalculated, or the cord is not properly connected to the jump platform. In 1986, a man died during rehearsals for a bungee jumping stunt on a BBC television programme, because the cord sprang loose from a carabiner clip. Injuries that occur despite safety measures generally relate to the abrupt rise in upper body intravascular pressure during bungee cord recoil. Eyesight damage is the most frequently reported complication. Impaired eyesight secondary to retinal haemorrhage may be transient or take several weeks to resolve. In one case, a 26-year-old woman's eyesight was still impaired after 7 months. Whiplash injuries may occur as the jumper is jolted on the bungee cord and in at least one case, this has led to quadrip...

    In the film GoldenEye, James Bond makes a jump over the edge of a dam in Russia (in reality the dam is in Switzerland: Verzasca Dam, and the jump was genuine, not an animated special effect). The jump in the dam later makes an appearance as a Roadblock task in the 14th season of the reality competition series The Amazing Race. A fictional proto-bungee jump is a plot point in the Michael Chabon novel The Amazing Adventures of Kavalier and Clay. In the film Selena, in which Jennifer Lopez plays SelenaQuintanilla-Perez, her character is shown bungee jumping at a carnival. This actual event took place shortly before Selena's murder on 31 March 1995. In Valiant (comics)#171 (January 8, 1966), the two boys from Worrag island in "The Wild Wonders" in a circus story, jump from high up and seem ready to crash to their deaths, but are stopped by elasticated ropes tied to an ankle of each one. In the video game Aero the Acro-Bat, Aero will perform bungee jumping to obtain items like keys to op...

    Srinivasan, Prianka (13 January 2020). "Bungee jumping came from Vanuatu — now Indigenous groups want to protect their customs". ABC News. Australian Broadcasting Corporation.

    Media related to Bungee jumpingat Wikimedia Commons
    The dictionary definition of bungee jumpingat Wiktionary
  9. Electric generator - Wikipedia

    en.wikipedia.org › wiki › Electric_generator
    • Terminology
    • History
    • Specialized Types of Generator
    • Common Use Cases
    • Equivalent Circuit

    Electromagneticgenerators fall into one of two broad categories, dynamos and alternators. 1. Dynamos generate pulsing direct current through the use of a commutator. 2. Alternators generate alternating current. Mechanically a generator consists of a rotating part and a stationary part: 1. Rotor: The rotating part of an electrical machine. 2. Stator: The stationary part of an electrical machine, which surrounds the rotor. One of these parts generates a magnetic field, the other has a wire winding in which the changing field induces an electric current: 1. Field winding or field (permanent) magnets: The magnetic field-producing component of an electrical machine. The magnetic field of the dynamo or alternator can be provided by either wire windings called field coils or permanent magnets. Electrically-excited generators include an excitation system to produce the field flux. A generator using permanent magnets (PMs) is sometimes called a magneto, or a permanent magnet synchronous gene...

    Before the connection between magnetism and electricity was discovered, electrostatic generators were invented. They operated on electrostatic principles, by using moving electrically charged belts, plates, and disks that carried charge to a high potential electrode. The charge was generated using either of two mechanisms: electrostatic induction or the triboelectric effect. Such generators generated very high voltage and low current. Because of their inefficiency and the difficulty of insulating machines that produced very high voltages, electrostatic generators had low power ratings, and were never used for generation of commercially significant quantities of electric power. Their only practical applications were to power early X-ray tubes, and later in some atomic particle accelerators.

    Direct current

    A dynamo uses commutators to produce direct current. It is self-excited, i.e. its field electromagnets are powered by the machine's own output. Other types of DC generators use a separate source of direct current to energize their field magnets.

    Power station

    A power station, also referred to as a power plant or powerhouse and sometimes generating station or generating plant, is an industrial facility for the generation of electric power. Most power stations contain one or more generators, a rotating machine that converts mechanical power into three-phase electric power. The relative motion between a magnetic field and a conductor creates an electrical current. The energy source harnessed to turn the generator varies widely. Most power stations in...

    Genset

    An engine-generator is the combination of an electrical generator and an engine (prime mover) mounted together to form a single piece of self-contained equipment. The engines used are usually piston engines, but gas turbines can also be used, and there are even hybrid diesel-gas units, called dual-fuel units. Many different versions of engine-generators are available - ranging from very small portable petrolpowered sets to large turbine installations. The primary advantage of engine-generator...

    Human powered electrical generators

    A generator can also be driven by human muscle power (for instance, in field radio station equipment). Human powered electric generators are commercially available, and have been the project of some DIY enthusiasts. Typically operated by means of pedal power, a converted bicycle trainer, or a foot pump, such generators can be practically used to charge batteries, and in some cases are designed with an integral inverter. An average "healthy human" can produce a steady 75 watts (0.1 horsepower)...

    An equivalent circuit of a generator and load is shown in the adjacent diagram. The generator is represented by an abstract generator consisting of an ideal voltage source and an internal impedance. The generator's V G {\\displaystyle V_{\\text{G}}} and R G {\\displaystyle R_{\\text{G}}} parameters can be determined by measuring the winding resistance (corrected to operating temperature), and measuring the open-circuit and loaded voltage for a defined current load. This is the simplest model of a generator, further elements may need to be added for an accurate representation. In particular, inductance can be added to allow for the machine's windings and magnetic leakage flux,but a full representation can become much more complex than this.

  10. Transformer - Wikipedia

    en.wikipedia.org › wiki › Transformer
    • Principles
    • Construction
    • Classification Parameters
    • Applications
    • History
    • Bibliography

    Ideal transformer

    An ideal transformer is a theoretical linear transformer that is lossless and perfectly coupled. Perfect coupling implies infinitely high core magnetic permeability and winding inductances and zero net magnetomotive force (i.e. ipnp - isns = 0).[c] A varying current in the transformer's primary winding attempts to create a varying magnetic flux in the transformer core, which is also encircled by the secondary winding. This varying flux at the secondary winding induces a varying electromotive...

    Transformer EMF equation

    If the flux in the core is purely sinusoidal, the relationship for either winding between its rms voltage Erms of the winding, and the supply frequency f, number of turns N, core cross-sectional area a in m2 and peak magnetic flux density Bpeak in Wb/m2or T (tesla) is given by the universal EMF equation: 1. E rms = 2 π f N a B peak 2 ≈ 4.44 f N a B peak {\\displaystyle E_{\\text{rms}}={\\frac {2\\pi fNaB_{\\text{peak}}}{\\sqrt {2}}}\\approx 4.44fNaB_{\\text{peak}}}

    Polarity

    A dot convention is often used in transformer circuit diagrams, nameplates or terminal markings to define the relative polarity of transformer windings. Positively increasing instantaneous current entering the primary winding's ‘dot’ end induces positive polarity voltage exiting the secondary winding's ‘dot’ end. Three-phase transformers used in electric power systems will have a nameplate that indicate the phase relationships between their terminals. This may be in the form of a phasordiagra...

    Cores

    Core form = core type; shell form = shell type Closed-core transformers are constructed in 'core form' or 'shell form'. When windings surround the core, the transformer is core form; when windings are surrounded by the core, the transformer is shell form. Shell form design may be more prevalent than core form design for distribution transformer applications due to the relative ease in stacking the core around winding coils. Core form design tends to, as a general rule, be more economical, and...

    Windings

    The electrical conductor used for the windings depends upon the application, but in all cases the individual turns must be electrically insulated from each other to ensure that the current travels throughout every turn. For small transformers, in which currents are low and the potential difference between adjacent turns is small, the coils are often wound from enamelled magnet wire. Larger power transformers may be wound with copper rectangular strip conductors insulated by oil-impregnated pa...

    Cooling

    It is a rule of thumb that the life expectancy of electrical insulation is halved for about every 7 °C to 10 °C increase in operating temperature (an instance of the application of the Arrhenius equation). Small dry-type and liquid-immersed transformers are often self-cooled by natural convection and radiation heat dissipation. As power ratings increase, transformers are often cooled by forced-air cooling, forced-oil cooling, water-cooling, or combinations of these. Large transformers are fil...

    Transformers can be classified in many ways, such as the following: 1. Power rating: From a fraction of a volt-ampere (VA) to over a thousand MVA. 2. Duty of a transformer: Continuous, short-time, intermittent, periodic, varying. 3. Frequency range: Power-frequency, audio-frequency, or radio-frequency. 4. Voltage class: From a few volts to hundreds of kilovolts. 5. Cooling type: Dry or liquid-immersed; self-cooled, forced air-cooled;forced oil-cooled, water-cooled. 6. Application: power supply, impedance matching, output voltage and current stabilizer, pulse, circuit isolation, power distribution, rectifier, arc furnace, amplifier output, etc.. 7. Basic magnetic form: Core form, shell form, concentric, sandwich. 8. Constant-potential transformer descriptor: Step-up, step-down, isolation. 9. General winding configuration: By IEC vector group, two-winding combinations of the phase designations delta, wye or star, and zigzag; autotransformer, Scott-T 10. Rectifier phase-shift winding c...

    Various specific electrical application designs require a variety of transformer types. Although they all share the basic characteristic transformer principles, they are customized in construction or electrical properties for certain installation requirements or circuit conditions. In electric power transmission, transformers allow transmission of electric power at high voltages, which reduces the loss due to heating of the wires. This allows generating plants to be located economically at a distance from electrical consumers.All but a tiny fraction of the world's electrical power has passed through a series of transformers by the time it reaches the consumer. In many electronic devices, a transformer is used to convert voltage from the distribution wiring to convenient values for the circuit requirements, either directly at the power line frequency or through a switch mode power supply. Signal and audio transformers are used to couple stages of amplifiers and to match devices such...

    Discovery of induction

    Electromagnetic induction, the principle of the operation of the transformer, was discovered independently by Michael Faraday in 1831 and Joseph Henry in 1832. Only Faraday furthered his experiments to the point of working out the equation describing the relationship between EMF and magnetic flux now known as Faraday's law of induction: 1. | E | = | d Φ B d t | , {\\displaystyle |{\\mathcal {E}}|=\\left|{{\\mathrm {d} \\Phi _{\\text{B}}} \\over \\mathrm {d} t}\\right|,} where | E | {\\displaystyle |{\\m...

    Induction coils

    The first type of transformer to see wide use was the induction coil, invented by Rev. Nicholas Callan of Maynooth College, Ireland in 1836. He was one of the first researchers to realize the more turns the secondary winding has in relation to the primary winding, the larger the induced secondary EMF will be. Induction coils evolved from scientists' and inventors' efforts to get higher voltages from batteries. Since batteries produce direct current (DC) rather than AC, induction coils relied...

    First alternating current transformers

    By the 1870s, efficient generators producing alternating current (AC) were available, and it was found AC could power an induction coil directly, without an interrupter. In 1876, Russian engineer Pavel Yablochkov invented a lighting system based on a set of induction coils where the primary windings were connected to a source of AC. The secondary windings could be connected to several 'electric candles'(arc lamps) of his own design. The coils Yablochkov employed functioned essentially as tran...

    Beeman, Donald, ed. (1955). Industrial Power Systems Handbook. McGraw-Hill.
    Calvert, James (2001). "Inside Transformers". University of Denver. Archived from the original on May 9, 2007. Retrieved May 19, 2007.
    Coltman, J. W. (Jan 1988). "The Transformer". Scientific American. 258 (1): 86–95. Bibcode:1988SciAm.258a..86C. doi:10.1038/scientificamerican0188-86. OSTI 6851152.
    Coltman, J.W. (Jan–Feb 2002). "The Transformer [Historical Overview]". IEEE Industry Applications Magazine. 8 (1): 8–15. doi:10.1109/2943.974352. S2CID 18160717.
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