Silver is a metallic element with symbol Ag and atomic number 47. The symbol Ag stems from Latin argentum, derived from the Greek ὰργὀς, a soft, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. The metal is found in the Earths crust in the pure, free form, as an alloy with gold and other metals. Most silver is produced as a byproduct of copper, lead, Silver is more abundant than gold, but it is much less abundant as a native metal. Its purity is measured on a per mille basis, a 94%-pure alloy is described as 0.940 fine. As one of the seven metals of antiquity, silver has had a role in most human cultures. Silver has long valued as a precious metal. Silver metal is used in many premodern monetary systems in bullion coins, Silver is used in numerous applications other than currency, such as solar panels, water filtration, ornaments, high-value tableware and utensils, and as an investment medium. Silver is used industrially in electrical contacts and conductors, in specialized mirrors, window coatings, Silver compounds are used in photographic film and X-rays.
Dilute silver nitrate solutions and other compounds are used as disinfectants and microbiocides, added to bandages and wound-dressings, catheters. Silver is similar in its physical and chemical properties to its two neighbours in group 11 of the periodic table and gold. This distinctive electron configuration, with an electron in the highest occupied s subshell over a filled d subshell. Silver is a soft and malleable transition metal. Silver crystallizes in a cubic lattice with bulk coordination number 12. Unlike metals with incomplete d-shells, metallic bonds in silver are lacking a covalent character and are relatively weak and this observation explains the low hardness and high ductility of single crystals of silver. Silver has a brilliant white metallic luster that can take a polish. Protected silver has greater optical reflectivity than aluminium at all wavelengths longer than ~450 nm, at wavelengths shorter than 450 nm, silvers reflectivity is inferior to that of aluminium and drops to zero near 310 nm.
The electrical conductivity of silver is the greatest of all metals, greater even than copper, during World War II in the US,13540 tons of silver were used in electromagnets for enriching uranium, mainly because of the wartime shortage of copper
A central bank, reserve bank, or monetary authority is an institution that manages a states currency, money supply, and interest rates. Central banks usually oversee the commercial banking system of their respective countries, Central banks in most developed nations are institutionally designed to be independent from political interference. Still, limited control by the executive and legislative bodies usually exists, prior to the 17th century most money was commodity money, typically gold or silver. However, promises to pay were widely circulated and accepted as value at least five hundred years earlier in both Europe and Asia. The Song dynasty was the first to issue generally circulating paper currency, in 1455, in an effort to control inflation, the succeeding Ming Dynasty ended the use of paper money and closed much of Chinese trade. The Bank of Amsterdam, established in the Dutch Republic in 1609, is considered to be the forerunner to modern central banks. The Wisselbanks innovations helped lay the foundations for the birth and development of the banking system that now plays a vital role in the worlds economy.
Along with a number of local banks, it performed many functions of a central banking system. Lucien Gillard calls it the European guilder, and Adam Smith devotes many pages to explaining how the bank guilder works, the model of the Wisselbank as a state bank was adapted throughout Europe, including the Bank of Sweden and the Bank of England. Established by Dutch-Latvian Johan Palmstruch in 1668, Sveriges Riksbank is often considered by many as the worlds oldest central bank, the lenders would give the government cash and issue notes against the government bonds, which could be lent again. A Royal Charter was granted on 27 July through the passage of the Tonnage Act 1694, the bank was given exclusive possession of the governments balances, and was the only limited-liability corporation allowed to issue banknotes. The £1. 2M was raised in 12 days, half of this was used to rebuild the Navy and these modern central banking functions evolved slowly through the 18th and 19th centuries. The currency crisis of 1797, caused by panicked depositors withdrawing from the Bank led to the government suspending convertibility of notes into specie payment.
The bank was accused by the bullionists of causing the exchange rate to fall from over issuing banknotes. Nevertheless, it was clear that the Bank was being treated as an organ of the state, henry Thornton, a merchant banker and monetary theorist has been described as the father of the modern central bank. An opponent of the real bills doctrine, he was a defender of the bullionist position, thorntons process of monetary expansion anticipated the theories of Knut Wicksell regarding the cumulative process which restates the Quantity Theory in a theoretically coherent form. Until the mid-nineteenth century, commercial banks were able to issue their own banknotes, many consider the origins of the central bank to lie with the passage of the Bank Charter Act of 1844. Under this law, authorisation to issue new banknotes was restricted to the Bank of England, at the same time, the Bank of England was restricted to issue new banknotes only if they were 100% backed by gold or up to £14 million in government debt
Cupronickel is an alloy of copper that contains nickel and strengthening elements, such as iron and manganese. Despite its high content, cupronickel is silver in colour. Cupronickel is highly resistant to corrosion in seawater because its potential is adjusted to be neutral with regard to seawater. Another common use of cupronickel is in silver-coloured modern-circulated coins, a typical mix is 75% copper, 25% nickel, and a trace amount of manganese. In the past, true silver coins were debased with cupronickel, Cupronickel alloys are used for marine applications due to their resistance to seawater corrosion, good fabricability, and their effectiveness in lowering macrofouling levels. Alloys ranging in composition from 90% Cu–10% Ni to 70% Cu–30% Ni are commonly specified in heat exchanger or condenser tubes in a variety of marine applications. Desalination plants, Cupronickel alloys are used in brine heaters, heat rejection and recovery, offshore oil and gas platforms and processing and FPSO vessels, Cupronickel alloys are used in systems and splash zone sheathings.
Power generation, Cupronickel alloys are used in steam turbine condensers, oil coolers, auxiliary cooling systems and high pressure pre-heaters at nuclear, seawater system design, Cupronickel alloys are used in tubular heat exchangers and condensers and high pressure systems. Seawater system components, Cupronickel alloys are used in condenser and heat exchanger tubes, piping, pumps, in Europe, Switzerland pioneered the nickel billon coinage in 1850, with the addition of silver. In 1968, Switzerland adopted the far cheaper 75,25 copper to nickel ratio being used by the Belgians, the United States, and Germany. From 1947 to 2012, all “silver” coinage in the UK was made from cupronickel, prior to these dates, both denominations had been made only in silver in the United States. Cupronickel is the cladding on either side of United States half-dollars since 1971, some circulating coins, such as the United States Jefferson nickel, the Swiss franc, and the South Korean 500 and 100 won are made of solid cupronickel.
Single-core thermocouple cables use a single pair of thermocouple conductors such as iron-constantan. These have the element of constantan or nickel-chromium alloy within a sheath of copper. Cupronickel is used in cryogenic applications, beginning around the turn of the 20th century, bullet jackets were commonly made from this material. It was soon replaced with gilding metal to reduce fouling in the bore. Currently, cupronickel remains the basic material for silver-plated cutlery and it is commonly used for mechanical and electrical equipment, medical equipment, jewelry items, and as material for strings for string instruments. Fender Musical Instruments used CuNiFe magnets in their Wide Range Humbucker pickup for various Telecaster and Starcaster guitars during the 1970s, for high-quality cylinder locks and locking systems, cylinder cores are made from wear-resistant cupronickel
East Germany, formally the German Democratic Republic, was an Eastern Bloc state during the Cold War period. The Soviet zone surrounded West Berlin, but did not include it, as a result, the German Democratic Republic was established in the Soviet Zone, while the Federal Republic was established in the three western zones. East Germany, which lies culturally in Central Germany, was a state of the Soviet Union. Soviet occupation authorities began transferring administrative responsibility to German communist leaders in 1948, Soviet forces, remained in the country throughout the Cold War. Until 1989, the GDR was governed by the Socialist Unity Party, though other parties participated in its alliance organisation. The economy was centrally planned, and increasingly state-owned, prices of basic goods and services were set by central government planners, rather than rising and falling through supply and demand. Although the GDR had to pay war reparations to the USSR. Nonetheless it did not match the growth of West Germany.
Emigration to the West was a significant problem—as many of the emigrants were well-educated young people, the government fortified its western borders and, in 1961, built the Berlin Wall. Many people attempting to flee were killed by guards or booby traps. In 1989, numerous social and political forces in the GDR and abroad led to the fall of the Berlin Wall, the following year open elections were held, and international negotiations led to the signing of the Final Settlement treaty on the status and borders of Germany. The GDR was dissolved and Germany was unified on 3 October 1990, the GDR bordered the Soviet sector of Allied-occupied Berlin known as East Berlin which was administered as the states de facto capital. It bordered the three sectors occupied by the United States, United Kingdom and France known collectively as West Berlin. The three sectors occupied by the Western nations were sealed off from the rest of the GDR by the Berlin Wall from its construction in 1961 until it was brought down in 1989, the official name was Deutsche Demokratische Republik, usually abbreviated to DDR.
West Germans, the media and statesmen purposely avoided the official name and its abbreviation, instead using terms like Ostzone, Sowjetische Besatzungszone. The centre of power in East Berlin was referred to as Pankow. Over time, the abbreviation DDR was used colloquially by West Germans. However, this use was not always consistent, for example, before World War II, Ostdeutschland was used to describe all the territories east of the Elbe, as reflected in the works of sociologist Max Weber and political theorist Carl Schmitt
Aluminium or aluminum is a chemical element in the boron group with symbol Al and atomic number 13. It is a silvery-white, nonmagnetic, ductile metal, Aluminium metal is so chemically reactive that native specimens are rare and limited to extreme reducing environments. Instead, it is combined in over 270 different minerals. The chief ore of aluminium is bauxite, Aluminium is remarkable for the metals low density and its ability to resist corrosion through the phenomenon of passivation. Aluminium and its alloys are vital to the industry and important in transportation and structures, such as building facades. The oxides and sulfates are the most useful compounds of aluminium, despite its prevalence in the environment, no known form of life uses aluminium salts metabolically, but aluminium is well tolerated by plants and animals. Because of these salts abundance, the potential for a role for them is of continuing interest. Aluminium is a soft, lightweight, ductile. It is nonmagnetic and does not easily ignite, a fresh film of aluminium serves as a good reflector of visible light and an excellent reflector of medium and far infrared radiation.
The yield strength of aluminium is 7–11 MPa, while aluminium alloys have yield strengths ranging from 200 MPa to 600 MPa. Aluminium has about one-third the density and stiffness of steel and it is easily machined, cast and extruded. Aluminium atoms are arranged in a cubic structure. Aluminium has an energy of approximately 200 mJ/m2. Aluminium is a thermal and electrical conductor, having 59% the conductivity of copper. Aluminium is capable of superconductivity, with a critical temperature of 1.2 kelvin. Aluminium is the most common material for the fabrication of superconducting qubits, the strongest aluminium alloys are less corrosion resistant due to galvanic reactions with alloyed copper. This corrosion resistance is reduced by aqueous salts, particularly in the presence of dissimilar metals. In highly acidic solutions, aluminium reacts with water to form hydrogen, primarily because it is corroded by dissolved chlorides, such as common sodium chloride, household plumbing is never made from aluminium
Mongolia /mɒŋˈɡoʊliə/ is a landlocked unitary sovereign state in East Asia. Its area is equivalent with the historical territory of Outer Mongolia. It is sandwiched between China to the south and Russia to the north, while it does not share a border with Kazakhstan, Mongolia is separated from it by only 36.76 kilometers. At 1,564,116 square kilometers, Mongolia is the 18th largest and it is the worlds second-largest landlocked country behind Kazakhstan and the largest landlocked country that does not border a closed sea. The country contains very little land, as much of its area is covered by grassy steppe, with mountains to the north and west. Ulaanbaatar, the capital and largest city, is home to about 45% of the countrys population, approximately 30% of the population is nomadic or semi-nomadic, horse culture is still integral. The majority of its population are Buddhists, the non-religious population is the second largest group. Islam is the dominant religion among ethnic Kazakhs, the majority of the states citizens are of Mongol ethnicity, although Kazakhs and other minorities live in the country, especially in the west.
Mongolia joined the World Trade Organization in 1997 and seeks to expand its participation in regional economic, the area of what is now Mongolia has been ruled by various nomadic empires, including the Xiongnu, the Xianbei, the Rouran, the Turkic Khaganate, and others. In 1206, Genghis Khan founded the Mongol Empire, which became the largest contiguous empire in history. His grandson Kublai Khan conquered China to establish the Yuan dynasty, after the collapse of the Yuan, the Mongols retreated to Mongolia and resumed their earlier pattern of factional conflict, except during the era of Dayan Khan and Tumen Zasagt Khan. In the 16th century, Tibetan Buddhism began to spread in Mongolia, being led by the Manchu-founded Qing dynasty. By the early 1900s, almost one-third of the male population were Buddhist monks. After the collapse of the Qing dynasty in 1911, Mongolia declared independence from the Qing dynasty, shortly thereafter, the country came under the control of the Soviet Union, which had aided its independence from China.
In 1924, the Mongolian Peoples Republic was declared as a Soviet satellite state, after the anti-Communist revolutions of 1989, Mongolia conducted its own peaceful democratic revolution in early 1990. This led to a multi-party system, a new constitution of 1992, homo erectus inhabited Mongolia from 850,000 years ago. Modern humans reached Mongolia approximately 40,000 years ago during the Upper Paleolithic, the Khoit Tsenkher Cave in Khovd Province shows lively pink and red ochre paintings of mammoths, bactrian camels, and ostriches, earning it the nickname the Lascaux of Mongolia. The venus figurines of Malta testify to the level of Upper Paleolithic art in northern Mongolia, the wheeled vehicles found in the burials of the Afanasevans have been dated to before 2200 BC
China, officially the Peoples Republic of China, is a unitary sovereign state in East Asia and the worlds most populous country, with a population of over 1.381 billion. The state is governed by the Communist Party of China and its capital is Beijing, the countrys major urban areas include Shanghai, Beijing, Shenzhen and Hong Kong. China is a power and a major regional power within Asia. Chinas landscape is vast and diverse, ranging from forest steppes, the Himalaya, Karakoram and Tian Shan mountain ranges separate China from much of South and Central Asia. The Yangtze and Yellow Rivers, the third and sixth longest in the world, Chinas coastline along the Pacific Ocean is 14,500 kilometers long and is bounded by the Bohai, East China and South China seas. China emerged as one of the worlds earliest civilizations in the basin of the Yellow River in the North China Plain. For millennia, Chinas political system was based on hereditary monarchies known as dynasties, in 1912, the Republic of China replaced the last dynasty and ruled the Chinese mainland until 1949, when it was defeated by the communist Peoples Liberation Army in the Chinese Civil War.
The Communist Party established the Peoples Republic of China in Beijing on 1 October 1949, both the ROC and PRC continue to claim to be the legitimate government of all China, though the latter has more recognition in the world and controls more territory. China had the largest economy in the world for much of the last two years, during which it has seen cycles of prosperity and decline. Since the introduction of reforms in 1978, China has become one of the worlds fastest-growing major economies. As of 2016, it is the worlds second-largest economy by nominal GDP, China is the worlds largest exporter and second-largest importer of goods. China is a nuclear weapons state and has the worlds largest standing army. The PRC is a member of the United Nations, as it replaced the ROC as a permanent member of the U. N. Security Council in 1971. China is a member of numerous formal and informal multilateral organizations, including the WTO, APEC, BRICS, the Shanghai Cooperation Organization, the BCIM, the English name China is first attested in Richard Edens 1555 translation of the 1516 journal of the Portuguese explorer Duarte Barbosa.
The demonym, that is, the name for the people, Portuguese China is thought to derive from Persian Chīn, and perhaps ultimately from Sanskrit Cīna. Cīna was first used in early Hindu scripture, including the Mahābhārata, there are, other suggestions for the derivation of China. The official name of the state is the Peoples Republic of China. The shorter form is China Zhōngguó, from zhōng and guó and it was applied to the area around Luoyi during the Eastern Zhou and to Chinas Central Plain before being used as an occasional synonym for the state under the Qing
Gold is a chemical element with symbol Au and atomic number 79. In its purest form, it is a bright, slightly yellow, soft, malleable. Chemically, gold is a metal and a group 11 element. It is one of the least reactive chemical elements and is solid under standard conditions, Gold often occurs in free elemental form, as nuggets or grains, in rocks, in veins, and in alluvial deposits. It occurs in a solid solution series with the element silver and naturally alloyed with copper. Less commonly, it occurs in minerals as gold compounds, often with tellurium, golds atomic number of 79 makes it one of the higher numbered, naturally occurring elements. It is thought to have produced in supernova nucleosynthesis, from the collision of neutron stars. Because the Earth was molten when it was formed, almost all of the present in the early Earth probably sank into the planetary core. Gold is resistant to most acids, though it does dissolve in aqua regia, a mixture of acid and hydrochloric acid. Gold dissolves in solutions of cyanide, which are used in mining and electroplating.
Gold dissolves in mercury, forming amalgam alloys, but this is not a chemical reaction, as a precious metal, gold has been used for coinage and other arts throughout recorded history. A total of 186,700 tonnes of gold is in existence above ground, the world consumption of new gold produced is about 50% in jewelry, 40% in investments, and 10% in industry. Gold is used in infrared shielding, colored-glass production, gold leafing, certain gold salts are still used as anti-inflammatories in medicine. As of 2014, the worlds largest gold producer by far was China with 450 tonnes, Gold is cognate with similar words in many Germanic languages, deriving via Proto-Germanic *gulþą from Proto-Indo-European *ǵʰelh₃-. The symbol Au is from the Latin, the Latin word for gold, the Proto-Indo-European ancestor of aurum was *h₂é-h₂us-o-, meaning glow. This word is derived from the root as *h₂éu̯sōs, the ancestor of the Latin word Aurora. This etymological relationship is presumably behind the frequent claim in scientific publications that aurum meant shining dawn, Gold is the most malleable of all metals, a single gram can be beaten into a sheet of 1 square meter, and an avoirdupois ounce into 300 square feet.
Gold leaf can be thin enough to become semi-transparent
Aluminium bronze is a type of bronze in which aluminium is the main alloying metal added to copper, in contrast to standard bronze or brass. The following table lists the most common standard aluminium bronze wrought alloy compositions, the percentages show the proportional composition of the alloy by weight. Copper is the remainder by weight and is not listed, Aluminium bronzes are most valued for their higher strength and they are resistant to corrosion in sea water. The addition of tin can improve corrosion resistance, another notable property of aluminium bronzes are their biostatic effects. Aluminium bronzes tend to have a golden color, Aluminium bronzes are most commonly used in applications where their resistance to corrosion makes them preferable to other engineering materials. These applications include plain bearings and landing gear components on aircraft, guitar strings, engine components, underwater fastenings in naval architecture, Aluminium bronze is used to fulfil the ATEX directive for Zones 1,2,21, and 22.
The attractive gold-toned coloration of aluminium bronzes has led to their use in jewellery, Aluminium bronze is used to replace gold for the casting of dental crowns. The alloys used are chemically inert and have the appearance of gold, publication Number 80, Aluminium Bronze Alloys Corrosion Resistance Guide, PDF. Publication Number 82, Aluminium Bronze Alloys Technical Data
The Soyombo symbol is a special character in the Soyombo alphabet invented by Zanabazar in 1686. The name Soyombo is derived from Sanskrit svayambhu self-created and it serves as a national symbol of Mongolia, to be found on the Flag of Mongolia, the Emblem of Mongolia, and on many other official documents. In the Soyombo alphabet, the two variations of the Soyombo symbol are used to mark the start and end of a text and it is thought to be possible that the symbol itself may predate the script. The Soyombo has ten elements in the arrangement of abstract and geometric symbols. They are fire, moon, two triangles, two rectangles, the Taiji and two vertical rectangles. The elements in the symbol are given the significance, Fire is a general symbol of eternal growth, wealth. The three tongues of the flame represent the past and future, sun and moon symbolise that the Mongolian nation will exist for eternity as the eternal blue sky. Mongolian symbol of the sun and fire derived from the Xiongnu, the two triangles allude to the point of an arrow or spear.
They point downward to announce the defeat of interior and exterior enemies, the two horizontal rectangles give stability to the round shape. The rectangular shape represents the honesty and justice of the people of Mongolia, the Taiji symbol illustrates the mutual complement of man and woman. In socialist times, it was interpreted as two fish symbolizing vigilance, because fish never close their eyes. The two vertical rectangles can be interpreted as the walls of a fort and they represent unity and strength, relating to a Mongolian proverb, The friendship of two is stronger than stone walls. The Soyombo symbol has appeared on the national Flag of Mongolia since 1911 and it served as the Emblem of Mongolia from 1924 to 1940, and was included in the design again in 1992. Mongolian Armed Forces vehicles bear the symbol as a marking, the symbol is seen all over the country, especially on a hillside outside of Ulaanbaatar. The flag and coat of arms of Buryatia as well as the flag of Agin-Buryat Okrug in Russia, and that of the Inner Mongolian Peoples Party display the top elements
Copper is a chemical element with symbol Cu and atomic number 29. It is a soft and ductile metal with high thermal and electrical conductivity. A freshly exposed surface of copper has a reddish-orange color. Copper is one of the few metals that occur in nature in directly usable metallic form as opposed to needing extraction from an ore and this led to very early human use, from c.8000 BC. Copper used in buildings, usually for roofing, oxidizes to form a green verdigris, Copper is sometimes used in decorative art, both in its elemental metal form and in compounds as pigments. Copper compounds are used as agents and wood preservatives. Copper is essential to all living organisms as a trace dietary mineral because it is a key constituent of the enzyme complex cytochrome c oxidase. In molluscs and crustaceans, copper is a constituent of the blood pigment hemocyanin, replaced by the hemoglobin in fish. In humans, copper is found mainly in the liver, the adult body contains between 1.4 and 2.1 mg of copper per kilogram of body weight.
The filled d-shells in these elements contribute little to interatomic interactions, unlike metals with incomplete d-shells, metallic bonds in copper are lacking a covalent character and are relatively weak. This observation explains the low hardness and high ductility of single crystals of copper, at the macroscopic scale, introduction of extended defects to the crystal lattice, such as grain boundaries, hinders flow of the material under applied stress, thereby increasing its hardness. For this reason, copper is supplied in a fine-grained polycrystalline form. The softness of copper partly explains its high conductivity and high thermal conductivity. The maximum permissible current density of copper in open air is approximately 3. 1×106 A/m2 of cross-sectional area, Copper is one of a few metallic elements with a natural color other than gray or silver. Pure copper is orange-red and acquires a reddish tarnish when exposed to air, as with other metals, if copper is put in contact with another metal, galvanic corrosion will occur. A green layer of verdigris can often be seen on old structures, such as the roofing of many older buildings.
Copper tarnishes when exposed to sulfur compounds, with which it reacts to form various copper sulfides. There are 29 isotopes of copper, 63Cu and 65Cu are stable, with 63Cu comprising approximately 69% of naturally occurring copper, both have a spin of 3⁄2