Nature, in the broadest sense, is the natural, physical, or material world or universe. "Nature" can refer to the phenomena of the physical world, to life in general. The study of nature is a large, part of science. Although humans are part of nature, human activity is understood as a separate category from other natural phenomena; the word nature is derived from the Latin word natura, or "essential qualities, innate disposition", in ancient times meant "birth". Natura is a Latin translation of the Greek word physis, which related to the intrinsic characteristics that plants and other features of the world develop of their own accord; the concept of nature as a whole, the physical universe, is one of several expansions of the original notion. This usage continued during the advent of modern scientific method in the last several centuries. Within the various uses of the word today, "nature" refers to geology and wildlife. Nature can refer to the general realm of living plants and animals, in some cases to the processes associated with inanimate objects—the way that particular types of things exist and change of their own accord, such as the weather and geology of the Earth.
It is taken to mean the "natural environment" or wilderness—wild animals, forest, in general those things that have not been altered by human intervention, or which persist despite human intervention. For example, manufactured objects and human interaction are not considered part of nature, unless qualified as, for example, "human nature" or "the whole of nature"; this more traditional concept of natural things which can still be found today implies a distinction between the natural and the artificial, with the artificial being understood as that, brought into being by a human consciousness or a human mind. Depending on the particular context, the term "natural" might be distinguished from the unnatural or the supernatural. Earth is the only planet known to support life, its natural features are the subject of many fields of scientific research. Within the solar system, it is third closest to the sun, its most prominent climatic features are its two large polar regions, two narrow temperate zones, a wide equatorial tropical to subtropical region.
Precipitation varies with location, from several metres of water per year to less than a millimetre. 71 percent of the Earth's surface is covered by salt-water oceans. The remainder consists of continents and islands, with most of the inhabited land in the Northern Hemisphere. Earth has evolved through geological and biological processes that have left traces of the original conditions; the outer surface is divided into several migrating tectonic plates. The interior remains active, with a thick layer of plastic mantle and an iron-filled core that generates a magnetic field; this iron core is composed of a solid inner phase, a fluid outer phase. Convective motion in the core generates electric currents through dynamo action, these, in turn, generate the geomagnetic field; the atmospheric conditions have been altered from the original conditions by the presence of life-forms, which create an ecological balance that stabilizes the surface conditions. Despite the wide regional variations in climate by latitude and other geographic factors, the long-term average global climate is quite stable during interglacial periods, variations of a degree or two of average global temperature have had major effects on the ecological balance, on the actual geography of the Earth.
Geology is the study of the solid and liquid matter that constitutes the Earth. The field of geology encompasses the study of the composition, physical properties and history of Earth materials, the processes by which they are formed and changed; the field is a major academic discipline, is important for mineral and hydrocarbon extraction, knowledge about and mitigation of natural hazards, some Geotechnical engineering fields, understanding past climates and environments. The geology of an area evolves through time as rock units are deposited and inserted and deformational processes change their shapes and locations. Rock units are first emplaced either by deposition onto the surface or intrude into the overlying rock. Deposition can occur when sediments settle onto the surface of the Earth and lithify into sedimentary rock, or when as volcanic material such as volcanic ash or lava flows, blanket the surface. Igneous intrusions such as batholiths, laccoliths and sills, push upwards into the overlying rock, crystallize as they intrude.
After the initial sequence of rocks has been deposited, the rock units can be deformed and/or metamorphosed. Deformation occurs as a result of horizontal shortening, horizontal extension, or side-to-side motion; these structural regimes broadly relate to convergent boundaries, divergent boundaries, transform boundaries between tectonic plates. Earth is estimated to have formed 4.54 billion years ago from the solar nebula, along with the Sun and other planets. The moon formed 20 million years later. Molten, the outer layer of the Earth cooled, resulting in the solid crust. Outgassing and volcanic activity produced the primordial atmosphere. Condensing water vapor, most or all of which came from ice delivered by comets, produced the oceans and other water sources; the energetic chemistry is believed to have produced a self-replicat
Sculpture is the branch of the visual arts that operates in three dimensions. It is one of the plastic arts. Durable sculptural processes used carving and modelling, in stone, ceramics and other materials but, since Modernism, there has been an complete freedom of materials and process. A wide variety of materials may be worked by removal such as carving, assembled by welding or modelling, or molded or cast. Sculpture in stone survives far better than works of art in perishable materials, represents the majority of the surviving works from ancient cultures, though conversely traditions of sculpture in wood may have vanished entirely. However, most ancient sculpture was brightly painted, this has been lost. Sculpture has been central in religious devotion in many cultures, until recent centuries large sculptures, too expensive for private individuals to create, were an expression of religion or politics; those cultures whose sculptures have survived in quantities include the cultures of the ancient Mediterranean and China, as well as many in Central and South America and Africa.
The Western tradition of sculpture began in ancient Greece, Greece is seen as producing great masterpieces in the classical period. During the Middle Ages, Gothic sculpture represented the agonies and passions of the Christian faith; the revival of classical models in the Renaissance produced famous sculptures such as Michelangelo's David. Modernist sculpture moved away from traditional processes and the emphasis on the depiction of the human body, with the making of constructed sculpture, the presentation of found objects as finished art works. A basic distinction is between sculpture in the round, free-standing sculpture, such as statues, not attached to any other surface, the various types of relief, which are at least attached to a background surface. Relief is classified by the degree of projection from the wall into low or bas-relief, high relief, sometimes an intermediate mid-relief. Sunk-relief is a technique restricted to ancient Egypt. Relief is the usual sculptural medium for large figure groups and narrative subjects, which are difficult to accomplish in the round, is the typical technique used both for architectural sculpture, attached to buildings, for small-scale sculpture decorating other objects, as in much pottery and jewellery.
Relief sculpture may decorate steles, upright slabs of stone also containing inscriptions. Another basic distinction is between subtractive carving techniques, which remove material from an existing block or lump, for example of stone or wood, modelling techniques which shape or build up the work from the material. Techniques such as casting and moulding use an intermediate matrix containing the design to produce the work; the term "sculpture" is used to describe large works, which are sometimes called monumental sculpture, meaning either or both of sculpture, large, or, attached to a building. But the term properly covers many types of small works in three dimensions using the same techniques, including coins and medals, hardstone carvings, a term for small carvings in stone that can take detailed work; the large or "colossal" statue has had an enduring appeal since antiquity. Another grand form of portrait sculpture is the equestrian statue of a rider on horse, which has become rare in recent decades.
The smallest forms of life-size portrait sculpture are the "head", showing just that, or the bust, a representation of a person from the chest up. Small forms of sculpture include the figurine a statue, no more than 18 inches tall, for reliefs the plaquette, medal or coin. Modern and contemporary art have added a number of non-traditional forms of sculpture, including sound sculpture, light sculpture, environmental art, environmental sculpture, street art sculpture, kinetic sculpture, land art, site-specific art. Sculpture is an important form of public art. A collection of sculpture in a garden setting can be called a sculpture garden. One of the most common purposes of sculpture is in some form of association with religion. Cult images are common in many cultures, though they are not the colossal statues of deities which characterized ancient Greek art, like the Statue of Zeus at Olympia; the actual cult images in the innermost sanctuaries of Egyptian temples, of which none have survived, were evidently rather small in the largest temples.
The same is true in Hinduism, where the simple and ancient form of the lingam is the most common. Buddhism brought the sculpture of religious figures to East Asia, where there seems to have been no earlier equivalent tradition, though again simple shapes like the bi and cong had religious significance. Small sculptures as personal possessions go back to the earliest prehistoric art, the use of large sculpture as public art to impress the viewer with the power of a ruler, goes back at least to the Great Sphinx of some 4,500 years ago. In archaeology and art history the appearance, sometimes disappearance, of large or monumental sculpture in a culture is regarded as of great significance, though tracing the emergence is complicated by the presumed existence of sculpture in wood and other perishable materials of which no record remains; the ability to s
Monel is a group of nickel alloys composed of nickel and copper, with small amounts of iron, manganese and silicon. Stronger than pure nickel, Monel alloys are resistant to corrosion by many agents, including flowing seawater, they can be fabricated by hot- and cold-working and welding. Monel was created by Robert Crooks Stanley, who worked for the International Nickel Company in 1901. Monel alloy 400 is a binary alloy of the same proportions of nickel and copper as is found in the nickel ore from the Sudbury mines and is therefore considered a puritan alloy. Monel was named after company president Ambrose Monell, patented in 1906. One L was dropped; the name is now a trademark of Special Metals Corporation. It is an expensive alloy, hence its use is limited to those applications where it cannot be replaced with cheaper alternatives. Compared to carbon steel, piping in Monel is more than 3 times as expensive. Monel is a solid-solution binary alloy; as nickel and copper are mutually soluble in all proportions, it is a single-phase alloy.
Compared to steel, Monel is difficult to machine as it work-hardens quickly. It needs to be worked at slow speeds and low feed rates, it is resistant to corrosion and acids, some alloys can withstand a fire in pure oxygen. It is used in applications with corrosive conditions. Small additions of aluminium and titanium form an alloy with the same corrosion resistance but with much greater strength due to gamma prime formation on aging. Monel is much more expensive than stainless steel. Monel alloy 400 has a specific gravity of 8.80, a melting range of 1300–1350 °C, an electrical conductivity of 34% IACS, a hardness of 65 Rockwell B. Monel alloy 400 is notable for its toughness, maintained over a considerable range of temperatures. Monel alloy 400 has excellent mechanical properties at subzero temperatures. Strength and hardness increase with only slight impairment of impact resistance; the alloy does not undergo a ductile-to-brittle transition when cooled to the temperature of liquid hydrogen. This is in marked contrast to many ferrous materials which are brittle at low temperatures despite their increased strength.
In the 1960s, Monel metal found bulk uses in aircraft construction in making the frames and skins of experimental rocket planes, such as the North American X-15, to resist the great heat generated by aerodynamic friction during high speed flight. Monel metal retains its strength at high temperatures, allowing it to maintain its shape at high atmospheric flight speeds, a trade off against the increased weight of the parts due to Monel's high density. Monel is used for safety wiring in aircraft maintenance to ensure that fasteners cannot come undone in high-temperature areas. Monel is used in the section of Alkylation units in direct contact with concentrated hydrofluoric acid. Monel offers exceptional resistance to hydrofluoric acid in all concentrations up to the boiling point, it is the most resistant of all used engineering alloys. The alloy is resistant to many forms of sulfuric and hydrochloric acids under reducing conditions. Monel's corrosion resistance makes it ideal in applications such as piping systems, pump shafts, seawater valves, trolling wire, strainer baskets.
Some alloys are non-magnetic and are used for anchor cable aboard minesweepers, housings for magnetic-field measurement equipment. In recreational boating, Monel wire is used to seize shackles for anchor ropes, Monel is used for water and fuel tanks, for underwater applications, it is used for propeller shafts and for keel bolts. On the popular Hobiecat sailboats, Monel rivets are used where strength is needed but stainless steel cannot be used due to corrosion problems that would result from having stainless steel in contact with the aluminum mast and frame of the boat, in a saltwater environment. However, because of the problem of electrolytic action in salt water, in shipbuilding Monel must be insulated from other metals such as steel; the New York Times on August 12, 1915 published an article about a 215-foot yacht, "the first ship, built with an Monel hull," that "went to pieces" in just six weeks and had to be scrapped, "on account of the disintegration of her bottom by electrical action."
The yacht's steel skeleton deteriorated due to electrolytic interaction with the Monel. In seabird research, bird banding or ringing in particular, Monel has been used to make bird bands or rings for many species such as albatross that live in a corrosive sea water environment. Monel is used as the material for valve pistons or rotors in some higher quality musical instruments such as trumpets and French horns. RotoSound introduced the use of Monel for electric bass strings in 1962, these strings have been used by numerous artists, including Steve Harris of Iron Maiden, The Who, John Deacon, John Paul Jones and the late Chris Squire. Monel was in use in the early 1930s by other musical string manufacturers, such as Gibson Guitar Corporation, who continue to offer them for mandolin as the Sam Bush signature set. C. F. Martin & Co. uses Monel for their Martin Retro acoustic guitar strings. The Pyramid string factory produces ` wound on a round core. In 2017, D'Addario string company released a line of violin strings using a Monel winding on the D and G string.
Good resistance against corrosion by acids and oxygen makes
Nickel is a chemical element with symbol Ni and atomic number 28. It is a silvery-white lustrous metal with a slight golden tinge. Nickel is hard and ductile. Pure nickel, powdered to maximize the reactive surface area, shows a significant chemical activity, but larger pieces are slow to react with air under standard conditions because an oxide layer forms on the surface and prevents further corrosion. So, pure native nickel is found in Earth's crust only in tiny amounts in ultramafic rocks, in the interiors of larger nickel–iron meteorites that were not exposed to oxygen when outside Earth's atmosphere. Meteoric nickel is found in combination with iron, a reflection of the origin of those elements as major end products of supernova nucleosynthesis. An iron–nickel mixture is thought to compose Earth's outer and inner cores. Use of nickel has been traced as far back as 3500 BCE. Nickel was first isolated and classified as a chemical element in 1751 by Axel Fredrik Cronstedt, who mistook the ore for a copper mineral, in the cobalt mines of Los, Hälsingland, Sweden.
The element's name comes from a mischievous sprite of German miner mythology, who personified the fact that copper-nickel ores resisted refinement into copper. An economically important source of nickel is the iron ore limonite, which contains 1–2% nickel. Nickel's other important ore minerals include pentlandite and a mixture of Ni-rich natural silicates known as garnierite. Major production sites include the Sudbury region in Canada, New Caledonia in the Pacific, Norilsk in Russia. Nickel is oxidized by air at room temperature and is considered corrosion-resistant, it has been used for plating iron and brass, coating chemistry equipment, manufacturing certain alloys that retain a high silvery polish, such as German silver. About 9% of world nickel production is still used for corrosion-resistant nickel plating. Nickel-plated objects sometimes provoke nickel allergy. Nickel has been used in coins, though its rising price has led to some replacement with cheaper metals in recent years. Nickel is one of four elements that are ferromagnetic at room temperature.
Alnico permanent magnets based on nickel are of intermediate strength between iron-based permanent magnets and rare-earth magnets. The metal is valuable in modern times chiefly in alloys. A further 10% is used for nickel-based and copper-based alloys, 7% for alloy steels, 3% in foundries, 9% in plating and 4% in other applications, including the fast-growing battery sector; as a compound, nickel has a number of niche chemical manufacturing uses, such as a catalyst for hydrogenation, cathodes for batteries and metal surface treatments. Nickel is an essential nutrient for some microorganisms and plants that have enzymes with nickel as an active site. Nickel is a silvery-white metal with a slight golden tinge, it is one of only four elements that are magnetic at or near room temperature, the others being iron and gadolinium. Its Curie temperature is 355 °C; the unit cell of nickel is a face-centered cube with the lattice parameter of 0.352 nm, giving an atomic radius of 0.124 nm. This crystal structure is stable to pressures of at least 70 GPa.
Nickel belongs to the transition metals. It is hard and ductile, has a high for transition metals electrical and thermal conductivity; the high compressive strength of 34 GPa, predicted for ideal crystals, is never obtained in the real bulk material due to the formation and movement of dislocations. The nickel atom has two electron configurations, 3d8 4s2 and 3d9 4s1, which are close in energy – the symbol refers to the argon-like core structure. There is some disagreement. Chemistry textbooks quote the electron configuration of nickel as 4s2 3d8, which can be written 3d8 4s2; this configuration agrees with the Madelung energy ordering rule, which predicts that 4s is filled before 3d. It is supported by the experimental fact that the lowest energy state of the nickel atom is a 3d8 4s2 energy level the 3d8 4s2 3F, J = 4 level. However, each of these two configurations splits into several energy levels due to fine structure, the two sets of energy levels overlap; the average energy of states with configuration 3d9 4s1 is lower than the average energy of states with configuration 3d8 4s2.
For this reason, the research literature on atomic calculations quotes the ground state configuration of nickel as 3d9 4s1. The isotopes of nickel range in atomic weight from 48 u to 78 u. Occurring nickel is composed of five stable isotopes. Isotopes heavier than 62Ni cannot be formed by nuclear fusion without losing energy. Nickel-62 has the highest mean nuclear binding energy per nucleon of any nuclide, at 8.7946 MeV/nucleon. Its binding energy is greater than both 56Fe and 58Fe, more abundant elements incorrectly cited as having the most tightly-bound nuclides. Although this would seem to predict nickel-62 as the most abundant heavy element in the universe, the high rate of photodisintegration of nickel in stellar interiors causes iron to be by far the most abundant. Stable isotope nickel-60 is the daughter product of the extinct radionuclide 60Fe, whi
Virtual International Authority File
The Virtual International Authority File is an international authority file. It is a joint project of several national libraries and operated by the Online Computer Library Center. Discussion about having a common international authority started in the late 1990s. After a series of failed attempts to come up with a unique common authority file, the new idea was to link existing national authorities; this would present all the benefits of a common file without requiring a large investment of time and expense in the process. The project was initiated by the US Library of Congress, the German National Library and the OCLC on August 6, 2003; the Bibliothèque nationale de France joined the project on October 5, 2007. The project transitioned to being a service of the OCLC on April 4, 2012; the aim is to link the national authority files to a single virtual authority file. In this file, identical records from the different data sets are linked together. A VIAF record receives a standard data number, contains the primary "see" and "see also" records from the original records, refers to the original authority records.
The data are available for research and data exchange and sharing. Reciprocal updating uses the Open Archives Initiative Protocol for Metadata Harvesting protocol; the file numbers are being added to Wikipedia biographical articles and are incorporated into Wikidata. VIAF's clustering algorithm is run every month; as more data are added from participating libraries, clusters of authority records may coalesce or split, leading to some fluctuation in the VIAF identifier of certain authority records. Authority control Faceted Application of Subject Terminology Integrated Authority File International Standard Authority Data Number International Standard Name Identifier Wikipedia's authority control template for articles Official website VIAF at OCLC
Système universitaire de documentation
The système universitaire de documentation or SUDOC is a system used by the libraries of French universities and higher education establishments to identify and manage the documents in their possession. The catalog, which contains more than 10 million references, allows students and researcher to search for bibliographical and location information in over 3,400 documentation centers, it is maintained by the Bibliographic Agency for Higher Education. Official website
Netherlands Institute for Art History
The Netherlands Institute for Art History or RKD is located in The Hague and is home to the largest art history center in the world. The center specializes in documentation and books on Western art from the late Middle Ages until modern times. All of this is open to the public, much of it has been digitized and is available on their website; the main goal of the bureau is to collect and make art research available, most notably in the field of Dutch Masters. Via the available databases, the visitor can gain insight into archival evidence on the lives of many artists of past centuries; the library owns 450,000 titles, of which ca. 150,000 are auction catalogs. There are ca. 3,000 magazines, of which 600 are running subscriptions. Though most of the text is in Dutch, the standard record format includes a link to library entries and images of known works, which include English as well as Dutch titles; the RKD manages the Dutch version of the Art and Architecture Thesaurus, a thesaurus of terms for management of information on art and architecture.
The original version is an initiative of the Getty Research Institute in California. The collection was started through bequests by Frits Lugt, art historian and owner of a massive collection of drawings and prints, Cornelis Hofstede de Groot, a collector, art historian and museum curator, their bequest formed the basis for both the art collection and the library, now housed in the Koninklijke Bibliotheek. Though not all of the library's holdings have been digitised, much of its metadata is accessible online; the website itself is available in both an English user interface. In the artist database RKDartists, each artist is assigned a record number. To reference an artist page directly, use the code listed at the bottom of the record of the form: https://rkd.nl/en/explore/artists/ followed by the artist's record number. For example, the artist record number for Salvador Dalí is 19752, so his RKD artist page can be referenced. In the images database RKDimages, each artwork is assigned a record number.
To reference an artwork page directly, use the code listed at the bottom of the record of the form: https://rkd.nl/en/explore/images/ followed by the artwork's record number. For example, the artwork record number for The Night Watch is 3063, so its RKD artwork page can be referenced; the Art and Architecture Thesaurus assigns a record for each term, but these can not be referenced online by record number. Rather, they are used in the databases and the databases can be searched for terms. For example, the painting called "The Night Watch" is a militia painting, all records fitting this keyword can be seen by selecting this from the image screen; the thesaurus is a set of general terms, but the RKD contains a database for an alternate form of describing artworks, that today is filled with biblical references. This is the iconclass database. To see all images that depict Miriam's dance, the associated iconclass code 71E1232 can be used as a special search term. Official website Direct link to the databases The Dutch version of the Art and Architecture Thesaurus