Aerospace is the human effort in science and business to fly in the atmosphere of Earth and surrounding space. Aerospace organizations research, manufacture, operate, or maintain aircraft or spacecraft. Aerospace activity is diverse, with a multitude of commercial and military applications. Aerospace is not the same as airspace, the physical air space directly above a location on the ground; the beginning of space and the ending of the air is considered as 100km above the ground according to the physical explanation that the air pressure is too low for a lifting body to generate meaningful lift force without exceeding orbital velocity. In most industrial countries, the aerospace industry is a cooperation of public and private industries. For example, several countries have a civilian space program funded by the government through tax collection, such as National Aeronautics and Space Administration in the United States, European Space Agency in Europe, the Canadian Space Agency in Canada, Indian Space Research Organisation in India, Japanese Aeronautics Exploration Agency in Japan, RKA in Russia, China National Space Administration in China, SUPARCO in Pakistan, Iranian Space Agency in Iran, Korea Aerospace Research Institute in South Korea.
Along with these public space programs, many companies produce technical tools and components such as spaceships and satellites. Some known companies involved in space programs include Boeing, Airbus, SpaceX, Lockheed Martin, United Technologies, MacDonald Dettwiler and Northrop Grumman; these companies are involved in other areas of aerospace such as the construction of aircraft. Modern aerospace began with Engineer George Cayley in 1799. Cayley proposed an aircraft with a "fixed wing and a horizontal and vertical tail," defining characteristics of the modern airplane; the 19th century saw the creation of the Aeronautical Society of Great Britain, the American Rocketry Society, the Institute of Aeronautical Sciences, all of which made aeronautics a more serious scientific discipline. Airmen like Otto Lilienthal, who introduced cambered airfoils in 1891, used gliders to analyze aerodynamic forces; the Wright brothers read several of his publications. They found inspiration in Octave Chanute, an airman and the author of Progress in Flying Machines.
It was the preliminary work of Cayley, Lilienthal and other early aerospace engineers that brought about the first powered sustained flight at Kitty Hawk, North Carolina on December 17, 1903, by the Wright brothers. War and science fiction inspired great minds like Konstantin Tsiolkovsky and Wernher von Braun to achieve flight beyond the atmosphere; the launch of Sputnik 1 in October 1957 started the Space Age, on July 20, 1969 Apollo 11 achieved the first manned moon landing. In April 1981, the Space Shuttle Columbia launched, the start of regular manned access to orbital space. A sustained human presence in orbital space started with "Mir" in 1986 and is continued by the "International Space Station". Space commercialization and space tourism are more recent features of aerospace. Aerospace manufacturing is a high-technology industry that produces "aircraft, guided missiles, space vehicles, aircraft engines, propulsion units, related parts". Most of the industry is geared toward governmental work.
For each original equipment manufacturer, the US government has assigned a Commercial and Government Entity code. These codes help to identify each manufacturer, repair facilities, other critical aftermarket vendors in the aerospace industry. In the United States, the Department of Defense and the National Aeronautics and Space Administration are the two largest consumers of aerospace technology and products. Others include the large airline industry; the aerospace industry employed 472,000 wage and salary workers in 2006. Most of those jobs were in Washington state and in California, with Missouri, New York and Texas being important; the leading aerospace manufacturers in the U. S. are United Technologies Corporation, SpaceX, Northrop Grumman and Lockheed Martin. These manufacturers are facing an increasing labor shortage as skilled U. S. workers retire. Apprenticeship programs such as the Aerospace Joint Apprenticeship Council work in collaboration with Washington state aerospace employers and community colleges to train new manufacturing employees to keep the industry supplied.
Important locations of the civilian aerospace industry worldwide include Washington state, California. In the European Union, aerospace companies such as EADS, BAE Systems, Dassault, Saab AB and Leonardo S.p. A. account for a large share of the global aerospace industry and research effort, with the European Space Agency as one of the largest consumers of aerospace technology and products. In India, Bangalore is a major center of the aerospace industry, where Hindustan Aeronautics Limited, the National Aerospace Laboratories and the Indian Space Research Organisation are headquartered; the Indian Space Research Organisation launched India's first Moon orbiter, Chandrayaan-1, in October 2008. In Russia, large aerospace companies like Oboronprom and the United Aircraft Building Corporation are among the major global players
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
A physicist is a scientist who specializes in the field of physics, which encompasses the interactions of matter and energy at all length and time scales in the physical universe. Physicists are interested in the root or ultimate causes of phenomena, frame their understanding in mathematical terms. Physicists work across a wide range of research fields, spanning all length scales: from sub-atomic and particle physics, through biological physics, to cosmological length scales encompassing the universe as a whole; the field includes two types of physicists: experimental physicists who specialize in the observation of physical phenomena and the analysis of experiments, theoretical physicists who specialize in mathematical modeling of physical systems to rationalize and predict natural phenomena. Physicists can apply their knowledge towards solving practical problems or to developing new technologies; the study and practice of physics is based on an intellectual ladder of discoveries and insights from ancient times to the present.
Many mathematical and physical ideas used today found their earliest expression in ancient Greek culture, for example in the work of Euclid, Thales of Miletus and Aristarchus. Roots emerged in ancient Asian culture and in the Islamic medieval period, for example the work of Alhazen in the 11th century; the modern scientific worldview and the bulk of physics education can be said to flow from the scientific revolution in Europe, starting with the work of Galileo Galilei and Johannes Kepler in the early 1600s. Newton's laws of motion and Newton's law of universal gravitation were formulated in the 17th century; the experimental discoveries of Faraday and the theory of Maxwell's equations of electromagnetism were developmental high points during the 19th century. Many physicists contributed to the development of quantum mechanics in the early-to-mid 20th century. New knowledge in the early 21st century includes a large increase in understanding physical cosmology; the broad and general study of nature, natural philosophy, was divided into several fields in the 19th century, when the concept of "science" received its modern shape.
Specific categories emerged, such as "biology" and "biologist", "physics" and "physicist", "chemistry" and "chemist", among other technical fields and titles. The term physicist was coined by William Whewell in his 1840 book The Philosophy of the Inductive Sciences. A standard undergraduate physics curriculum consists of classical mechanics and magnetism, non-relativistic quantum mechanics, statistical mechanics and thermodynamics, laboratory experience. Physics students need training in mathematics, in computer science. Any physics-oriented career position requires at least an undergraduate degree in physics or applied physics, while career options widen with a Master's degree like MSc, MPhil, MPhys or MSci. For research-oriented careers, students work toward a doctoral degree specializing in a particular field. Fields of specialization include experimental and theoretical astrophysics, atomic physics, biological physics, chemical physics, condensed matter physics, geophysics, gravitational physics, material science, medical physics, molecular physics, nuclear physics, radiophysics, electromagnetic field and microwave physics, particle physics, plasma physics.
The highest honor awarded to physicists is the Nobel Prize in Physics, awarded since 1901 by the Royal Swedish Academy of Sciences. National physics professional societies have many awards for professional recognition. In the case of the American Physical Society, as of 2017, there are 33 separate prizes and 38 separate awards in the field; the three major employers of career physicists are academic institutions and private industries, with the largest employer being the last. Physicists in academia or government labs tend to have titles such as Assistants, Professors, Sr./Jr. Scientist, or postdocs; as per the American Institute of Physics, some 20% of new physics Ph. D.s holds jobs in engineering development programs, while 14% turn to computer software and about 11% are in business/education. A majority of physicists employed apply their skills and training to interdisciplinary sectors. Job titles for graduate physicists include Agricultural Scientist, Air Traffic Controller, Computer Programmer, Electrical Engineer, Environmental Analyst, Medical Physicist, Oceanographer, Physics Teacher/Professor/Researcher, Research Scientist, Reactor Physicist, Engineering Physicist, Satellite Missions Analyst, Science Writer, Software Engineer, Systems Engineer, Microelectronics Engineer, Radar Developer, Technical Consultant, etc.
A majority of Physics terminal bachelor's degree holders are employed in the private sector. Other fields are academia and military service, nonprofit entities and teaching. Typical duties of physicists with master's and doctoral degrees working in their domain involve research and analysis, data preparation, instrumentation and development of industrial or medical equipment and software development, etc. Chartered Physicist is a chartered status and a professional qualification awarded by the Institute of Physics, it is denoted by the postnominals "CPhys". Achieving chartered status in any profession denotes to the wider community a high level of specialised subject knowledge and professional competence. According to the Institute of Physics, holders of the award of the Chartered Physicist demonst
Classical mechanics describes the motion of macroscopic objects, from projectiles to parts of machinery, astronomical objects, such as spacecraft, planets and galaxies. If the present state of an object is known it is possible to predict by the laws of classical mechanics how it will move in the future and how it has moved in the past; the earliest development of classical mechanics is referred to as Newtonian mechanics. It consists of the physical concepts employed by and the mathematical methods invented by Isaac Newton and Gottfried Wilhelm Leibniz and others in the 17th century to describe the motion of bodies under the influence of a system of forces. More abstract methods were developed, leading to the reformulations of classical mechanics known as Lagrangian mechanics and Hamiltonian mechanics; these advances, made predominantly in the 18th and 19th centuries, extend beyond Newton's work through their use of analytical mechanics. They are, with some modification used in all areas of modern physics.
Classical mechanics provides accurate results when studying large objects that are not massive and speeds not approaching the speed of light. When the objects being examined have about the size of an atom diameter, it becomes necessary to introduce the other major sub-field of mechanics: quantum mechanics. To describe velocities that are not small compared to the speed of light, special relativity is needed. In case that objects become massive, general relativity becomes applicable. However, a number of modern sources do include relativistic mechanics into classical physics, which in their view represents classical mechanics in its most developed and accurate form; the following introduces the basic concepts of classical mechanics. For simplicity, it models real-world objects as point particles; the motion of a point particle is characterized by a small number of parameters: its position and the forces applied to it. Each of these parameters is discussed in turn. In reality, the kind of objects that classical mechanics can describe always have a non-zero size.
Objects with non-zero size have more complicated behavior than hypothetical point particles, because of the additional degrees of freedom, e.g. a baseball can spin while it is moving. However, the results for point particles can be used to study such objects by treating them as composite objects, made of a large number of collectively acting point particles; the center of mass of a composite object behaves like a point particle. Classical mechanics uses common-sense notions of how matter and forces interact, it assumes that matter and energy have definite, knowable attributes such as location in space and speed. Non-relativistic mechanics assumes that forces act instantaneously; the position of a point particle is defined in relation to a coordinate system centered on an arbitrary fixed reference point in space called the origin O. A simple coordinate system might describe the position of a particle P with a vector notated by an arrow labeled r that points from the origin O to point P. In general, the point particle does not need to be stationary relative to O.
In cases where P is moving relative to O, r is defined as a function of time. In pre-Einstein relativity, time is considered an absolute, i.e. the time interval, observed to elapse between any given pair of events is the same for all observers. In addition to relying on absolute time, classical mechanics assumes Euclidean geometry for the structure of space; the velocity, or the rate of change of position with time, is defined as the derivative of the position with respect to time: v = d r d t. In classical mechanics, velocities are directly subtractive. For example, if one car travels east at 60 km/h and passes another car traveling in the same direction at 50 km/h, the slower car perceives the faster car as traveling east at 60 − 50 = 10 km/h. However, from the perspective of the faster car, the slower car is moving 10 km/h to the west denoted as -10 km/h where the sign implies opposite direction. Velocities are directly additive as vector quantities. Mathematically, if the velocity of the first object in the previous discussion is denoted by the vector u = ud and the velocity of the second object by the vector v = ve, where u is the speed of the first object, v is the speed of the second object, d and e are unit vectors in the directions of motion of each object then the velocity of the first object as seen by the second object is u ′ = u − v. Similarly, the first object sees the velocity of the second object as v ′ = v − u.
When both objects are moving in the same direction, this equation can be simplified to u ′ = d. Or, by ignoring direction, the difference can be given in terms of speed only: u ′ = u − v; the acceleration, or rate of change of velocity, is th
Sofia University, "St. Kliment Ohridski" at the University of Sofia, is the oldest higher education institution in Bulgaria. Founded on 1 October 1888, the edifice of the university was constructed between 1924 and 1934 with the financial support of the brothers Evlogi Georgiev and Hristo Georgiev and has an area of 18,624 m² and a total of 324 premises; the university has 16 faculties and three departments, where over 21,000 students receive their education. The current rector is Anastas Gerdzhikov, it has been ranked as the top university in Bulgaria according to national and international rankings, being among the best four percent of world universities according to QS World University Rankings. The university was founded on 1 October 1888—ten years after the liberation of Bulgaria—to serve as Bulgaria's primary institution of higher education, it had 4 regular and 3 additional lecturers and 49 students. It was founded as a higher pedagogical course, it became a higher school after a few months and a university in 1904.
The first rector was Bulgarian linguist Aleksandar Teodorov-Balan. During Sofia University's first years, it had three faculties, namely a Faculty of History and Philology, a Faculty of Mathematics and Physics and a Faculty of Law. History, Slavic philology and pedagogics, mathematics and physics, natural sciences and law were taught; the first women were welcomed to the university in 1901 and 25 November, the day of St. Kliment of Ohrid, became the university's official holiday the following year; as Prince Ferdinand opened the National Theatre in 1907, he was booed by Sofia University students, for which the university was closed for six months and all lecturers were fired. Not until a new government with Aleksandar Malinov at the head came into power in January 1908 was the crisis resolved. At the beginning of the Balkan Wars, 1,379 students were recorded to attend the university. A fourth faculty was established in 1917, the Faculty of Medicine, the fifth, the Faculty of Agronomy following in 1921, the Faculty of Veterinary Medicine and the Faculty of Theology being founded in 1923.
In 1922–1923, Sofia University had 111 chairs, 205 lecturers and assistants and 2,388 students, of which 1,702 men and 686 women. The foundation stone of Sofia University's new edifice was laid on 30 June 1924. Funds were secured by the brothers Evlogi Hristo Georgiev; the rectorate was built according to the initial plans of the French architect Henri Bréançon, who had won a competition for the purpose in 1907. The plans were developed by Nikola Lazarov and revised by Yordan Milanov, who directed the construction, but died before the official opening on 16 December 1934. On 27 October 1929, the first doctoral thesis in natural science of the university was defended by geologist Vassil Tzankov; the second one in chemistry followed on 1 July 1930 and the title doctor was granted to Aleksandar Spasov. In 1930–1931, the university had four more doctors. After the political changes of 9 September 1944 and the emergence of the People's Republic of Bulgaria, radical alterations were made in the university system of the country.
At that time in 1944–1945, 13,627 students attended the university, taught by 182 professors and readers and 286 assistants. Communist professors were introduced to the higher ranks of university authority, with others that did not share these views being removed. Specific party-related chairs were established and the university was restricted after the Soviet model. Three new faculties were founded in 1947, one of forestry, one of zootechnics and one of economics and major changes occurred, with many departments seceding in years to form separate institutions. Sofia University Mountains on Alexander Island, Antarctica were named for the university in commemoration of its centennial celebrated in 1988 and in appreciation of the university’s contribution to the Antarctic exploration. Sofia University offers a wide range of degrees in 16 faculties: Faculty of Biology Faculty of Chemistry and Pharmacy Faculty of Classical and Modern Philology Faculty of Economics and Business Administration Faculty of Education Faculty of Geology and Geography Faculty of History Faculty of Journalism and Mass Communication Faculty of Law Faculty of Mathematics and Informatics Faculty of Philosophy Faculty of Physics Faculty of Pre-school and Primary School Education Faculty of Slavic Studies Faculty of Theology Faculty of Medicine Department of Language Learning Department for Information and In-service Training of Teachers Sports Department Balkan Universities Network National Centre of Polar Research Elisaveta Bagryana, poet Anthony Bailey, businessman Kiril Bratanov, scientist Ljubomir Chakaloff, mathematician Boris Christoff, opera singer Raymond Detrez, historian Philip Dimitrov and lawyer, former Prime Minister of Bulgaria and member of the Constitutional Court of Bulgaria Khristo Ivanov, scientist Rostislaw Kaischew, scientist Ivan Kostov and economist, former Prime Minister of Bulgaria / Julia Kristeva and writer Maxim and head of the Bulgarian Orthodox Church Georgi Nadjakov, physicist Ivan Kostov Nikolov and mineralogist Ya'akov Nitzani, Knesset member Georgi Parvanov, former President of Bulgaria Assen Razcvetnikov, poet and translator Dimitar Sasselov, astronomer Petar Stoyanov, former President of Bulgaria / Ivan Stranski, physical chemist / Tzvetan Todorov, philosopher Orlin D. Velev and scientist Mikhail Wehbe, diplomat Zhelyu Z
Bulgaria the Republic of Bulgaria, is a country in Southeast Europe. It is bordered by Romania to the north and North Macedonia to the west and Turkey to the south, the Black Sea to the east; the capital and largest city is Sofia. With a territory of 110,994 square kilometres, Bulgaria is Europe's 16th-largest country. One of the earliest societies in the lands of modern-day Bulgaria was the Neolithic Karanovo culture, which dates back to 6,500 BC. In the 6th to 3rd century BC the region was a battleground for Thracians, Persians and ancient Macedonians; the Eastern Roman, or Byzantine, Empire lost some of these territories to an invading Bulgar horde in the late 7th century. The Bulgars founded the First Bulgarian Empire in AD 681, which dominated most of the Balkans and influenced Slavic cultures by developing the Cyrillic script; this state lasted until the early 11th century, when Byzantine emperor Basil II conquered and dismantled it. A successful Bulgarian revolt in 1185 established a Second Bulgarian Empire, which reached its apex under Ivan Asen II.
After numerous exhausting wars and feudal strife, the Second Bulgarian Empire disintegrated in 1396 and its territories fell under Ottoman rule for nearly five centuries. The Russo-Turkish War of 1877–78 resulted in the formation of the current Third Bulgarian State. Many ethnic Bulgarian populations were left outside its borders, which led to several conflicts with its neighbours and an alliance with Germany in both world wars. In 1946 Bulgaria became part of the Soviet-led Eastern Bloc; the ruling Communist Party gave up its monopoly on power after the revolutions of 1989 and allowed multi-party elections. Bulgaria transitioned into a democracy and a market-based economy. Since adopting a democratic constitution in 1991, the sovereign state has been a unitary parliamentary republic with a high degree of political and economic centralisation; the population of seven million lives in Sofia and the capital cities of the 27 provinces, the country has suffered significant demographic decline since the late 1980s.
Bulgaria is a member of the European Union, NATO, the Council of Europe. Its market economy is part of the European Single Market and relies on services, followed by industry—especially machine building and mining—and agriculture. Widespread corruption is a major socioeconomic issue; the name Bulgaria is derived from a tribe of Turkic origin that founded the country. Their name is not understood and difficult to trace back earlier than the 4th century AD, but it is derived from the Proto-Turkic word bulģha and its derivative bulgak; the meaning may be further extended to "rebel", "incite" or "produce a state of disorder", i.e. the "disturbers". Ethnic groups in Inner Asia with phonologically similar names were described in similar terms: during the 4th century, the Buluoji, a component of the "Five Barbarian" groups in Ancient China, were portrayed as both a "mixed race" and "troublemakers". Neanderthal remains dating to around 150,000 years ago, or the Middle Paleolithic, are some of the earliest traces of human activity in the lands of modern Bulgaria.
The Karanovo culture arose circa 6,500 BC and was one of several Neolithic societies in the region that thrived on agriculture. The Copper Age Varna culture is credited with inventing gold metallurgy; the associated Varna Necropolis treasure contains the oldest golden jewellery in the world with an approximate age of over 6,000 years. The treasure has been valuable for understanding social hierarchy and stratification in the earliest European societies; the Thracians, one of the three primary ancestral groups of modern Bulgarians, appeared on the Balkan Peninsula some time before the 12th century BC. The Thracians excelled in metallurgy and gave the Greeks the Orphean and Dionysian cults, but remained tribal and stateless; the Persian Achaemenid Empire conquered most of present-day Bulgaria in the 6th century BC and retained control over the region until 479 BC. The invasion became a catalyst for Thracian unity, the bulk of their tribes united under king Teres to form the Odrysian kingdom in the 470s BC.
It was weakened and vassalized by Philip II of Macedon in 341 BC, attacked by Celts in the 3rd century, became a province of the Roman Empire in AD 45. By the end of the 1st century AD, Roman governance was established over the entire Balkan Peninsula and Christianity began spreading in the region around the 4th century; the Gothic Bible—the first Germanic language book—was created by Gothic bishop Ulfilas in what is today northern Bulgaria around 381. The region came under Byzantine control after the fall of Rome in 476; the Byzantines were engaged in prolonged warfare against Persia and could not defend their Balkan territories from barbarian incursions. This enabled the Slavs to enter the Balkan Peninsula as marauders through an area between the Danube River and the Balkan Mountains known as Moesia; the interior of the peninsula became a country of the South Slavs, who lived under a democracy. The Slavs assimilated the Hellenized and Gothicized Thracians in the rural areas. Not l