1.
Anti-aircraft warfare
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Anti-aircraft warfare or counter-air defence is defined by NATO as all measures designed to nullify or reduce the effectiveness of hostile air action. They include ground-and air-based weapon systems, associated sensor systems, command and control arrangements and it may be used to protect naval, ground, and air forces in any location. However, for most countries the main effort has tended to be homeland defence, NATO refers to airborne air defence as counter-air and naval air defence as anti-aircraft warfare. Missile defence is an extension of air defence as are initiatives to adapt air defence to the task of intercepting any projectile in flight, a surface-based air defence capability can also be deployed offensively to deny the use of airspace to an opponent. Until the 1950s, guns firing ballistic munitions ranging from 20 mm to 150 mm were the weapons, guided missiles then became dominant. The term air defence was probably first used by Britain when Air Defence of Great Britain was created as a Royal Air Force command in 1925. However, arrangements in the UK were also called anti-aircraft, abbreviated as AA, after the First World War it was sometimes prefixed by Light or Heavy to classify a type of gun or unit. Nicknames for anti-aircraft guns include AA, AAA or triple-A, an abbreviation of anti-aircraft artillery, ack-ack, NATO defines anti-aircraft warfare as measures taken to defend a maritime force against attacks by airborne weapons launched from aircraft, ships, submarines and land-based sites. In some armies the term All-Arms Air Defence is used for air defence by nonspecialist troops, other terms from the late 20th century include GBAD with related terms SHORAD and MANPADS. Anti-aircraft missiles are variously called surface-to-air missile, abbreviated and pronounced SAM, non-English terms for air defence include the German FlaK, whence English flak, and the Russian term Protivovozdushnaya oborona, a literal translation of anti-air defence, abbreviated as PVO. In Russian the AA systems are called zenitnye systems, in French, air defence is called DCA. The maximum distance at which a gun or missile can engage an aircraft is an important figure, however, many different definitions are used but unless the same definition is used, performance of different guns or missiles cannot be compared. For AA guns only the part of the trajectory can be usefully used. By the late 1930s the British definition was that height at which an approaching target at 400 mph can be engaged for 20 seconds before the gun reaches 70 degrees elevation. However, effective ceiling for heavy AA guns was affected by nonballistic factors, The maximum running time of the fuse, the capability of fire control instruments to determine target height at long range. The essence of air defence is to detect aircraft and destroy them. The critical issue is to hit a target moving in three-dimensional space, Air defence evolution covered the areas of sensors and technical fire control, weapons, and command and control. At the start of the 20th century these were very primitive or non-existent
2.
Battery (electricity)
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An electric battery is a device consisting of one or more electrochemical cells with external connections provided to power electrical devices such as flashlights, smartphones, and electric cars. When a battery is supplying power, its positive terminal is the cathode. The terminal marked negative is the source of electrons that when connected to a circuit will flow. It is the movement of ions within the battery which allows current to flow out of the battery to perform work. Historically the term specifically referred to a device composed of multiple cells. Primary batteries are used once and discarded, the materials are irreversibly changed during discharge. Common examples are the battery used for flashlights and a multitude of portable electronic devices. Secondary batteries can be discharged and recharged multiple times using mains power from a wall socket, examples include the lead-acid batteries used in vehicles and lithium-ion batteries used for portable electronics such as laptops and smartphones. According to a 2005 estimate, the battery industry generates US$48 billion in sales each year. Batteries have much lower energy than common fuels such as gasoline. This is somewhat offset by the efficiency of electric motors in producing mechanical work. The usage of battery to describe a group of electrical devices dates to Benjamin Franklin, alessandro Volta built and described the first electrochemical battery, the voltaic pile, in 1800. This was a stack of copper and zinc plates, separated by brine-soaked paper disks, Volta did not understand that the voltage was due to chemical reactions. Although early batteries were of value for experimental purposes, in practice their voltages fluctuated. It consisted of a pot filled with a copper sulfate solution, in which was immersed an unglazed earthenware container filled with sulfuric acid. These wet cells used liquid electrolytes, which were prone to leakage and spillage if not handled correctly, many used glass jars to hold their components, which made them fragile and potentially dangerous. These characteristics made wet cells unsuitable for portable appliances, near the end of the nineteenth century, the invention of dry cell batteries, which replaced the liquid electrolyte with a paste, made portable electrical devices practical. Batteries convert chemical energy directly to electrical energy, a battery consists of some number of voltaic cells
3.
International Electrotechnical Commission
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The IEC also manages three global conformity assessment systems that certify whether equipment, system or components conform to its International Standards. The first International Electrical Congress took place in 1881 at the International Exposition of Electricity, at that time the International System of Electrical and Magnetic Units was agreed to. The IEC was instrumental in developing and distributing standards for units of measurement, particularly Gauss, Hertz and it also first proposed a system of standards, the Giorgi System, which ultimately became the SI, or Système International d’unités. In 1938, it published a multilingual international vocabulary to unify terminology relating to electrical, electronic and this effort continues, and the International Electrotechnical Vocabulary remains an important work in the electrical and electronic industries. The CISPR – in English, the International Special Committee on Radio Interference – is one of the groups founded by the IEC, originally located in London, the commission moved to its current headquarters in Geneva in 1948. It has regional centres in Asia-Pacific, Latin America and North America, today, the IEC is the worlds leading international organization in its field, and its standards are adopted as national standards by its members. The work is done by some 10,000 electrical and electronics experts from industry, government, academia, test labs, IEC standards have numbers in the range 60000–79999 and their titles take a form such as IEC60417, Graphical symbols for use on equipment. Following the Dresden Agreement with CENELEC the numbers of older IEC standards were converted in 1997 by adding 60000, for example IEC27 became IEC60027. Standards of the 60000 series are also preceded by EN to indicate that the IEC standard is also adopted by CENELEC as a European standard. The IEC cooperates closely with the International Organization for Standardization and the International Telecommunication Union, Standards developed jointly with ISO such as ISO/IEC26300, ISO/IEC27001, and CASCO ISO/IEC17000 series, carry the acronym of both organizations. The use of the ISO/IEC prefix covers publications from ISO/IEC Joint Technical Committee 1 - Information Technology, as well as conformity assessment standards developed by ISO CASCO, other standards developed in cooperation between IEC and ISO are assigned numbers in the 80000 series, such as IEC 82045-1. IEC standards are also being adopted by other certifying bodies such as BSI, CSA, UL & ANSI/INCITS, SABS, SAI, SPC/GB, IEC standards adopted by other certifying bodies may have some noted differences from the original IEC standard. The IEC is made up of members, called national committees, national committees are constituted in different ways. Some NCs are public sector only, some are a combination of public and private sector, about 90% of those who prepare IEC standards work in industry
4.
Japanese Industrial Standards
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Japanese Industrial Standards specifies the standards used for industrial activities in Japan. The standardization process is coordinated by the Japanese Industrial Standards Committee, Japanese Industrial Standards Committee is composed of many nationwide committees and plays vital role in standardizing activities in Japan. These were summarized to form a standard in 1921. During World War II, simplified standards were established to increase matériel output, the present Japanese Standards Association was established after Japans defeat in World War II in 1945. The Japanese Industrial Standards Committee regulations were promulgated in 1946, Japanese standards was formed, the Industrial Standardization Law was enacted in 1949, which forms the legal foundation for the present Japanese Industrial Standards. The Industrial Standardization Law was revised in 2004 and the JIS mark was changed, since October 1,2005, therefore all JIS-certified Japanese products have had the new JIS mark since October 1,2008. Standards are named like JIS X0208,1997, where X denotes area division, followed by four digits, and the revision release year
5.
Alkaline battery
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Alkaline batteries are a type of primary battery dependent upon the reaction between zinc and manganese dioxide. Another type of batteries are secondary rechargeable alkaline battery, which allows reuse of specially designed cells. Compared with zinc-carbon batteries of the Leclanché or zinc chloride types, alkaline batteries have an energy density and longer shelf-life. The alkaline battery gets its name because it has an electrolyte of potassium hydroxide. Other battery systems also use alkaline electrolytes, but they use different active materials for the electrodes, Alkaline batteries account for 80% of manufactured batteries in the US and over 10 billion individual units produced worldwide. In Japan alkaline batteries account for 46% of all battery sales. In Switzerland alkaline batteries account for 68%, in the UK 60%, Alkaline batteries are used in many household items such as MP3 players, CD players, digital cameras, pagers, toys, lights, and radios, to name a few. Batteries with alkaline electrolyte were first developed by Waldemar Jungner in 1899, on October 9,1957, Urry, Karl Kordesch, and P. A. Marsal filed US patent for the alkaline battery and it was granted in 1960 and was assigned to the Union Carbide Corporation. When introduced in the late 1960s, alkaline batteries contained a small amount of mercury amalgam to control side reactions at the zinc anode. With mercury content reduced by law and improvements in the purity and consistency of materials, in an alkaline battery, the negative electrode is zinc and the positive electrode is manganese dioxide. The alkaline electrolyte of potassium hydroxide is not part of the reaction, only the zinc, the alkaline electrolyte of potassium hydroxide remains, as there are equal amounts of OH− consumed and produced. An alkaline cell can provide three and five times capacity. The capacity of a battery is strongly dependent on the load. An AA-sized alkaline battery might have a capacity of 3000 mAh at low drain, but at a load of 1 ampere, which is common for digital cameras. The voltage of the battery declines steadily during use, so the usable capacity depends on the cut-off voltage of the application. Unlike Leclanche cells, the alkaline cell delivers about as much capacity on intermittent or continuous light loads, on a heavy load, capacity is reduced on continuous discharge compared with intermittent discharge, but the reduction is less than for Leclanche cells. The nominal voltage of an alkaline cell as established by manufacturer standards is 1.5 V
