South Dakota is a U. S. state in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux Native American tribes, who compose a large portion of the population and dominated the territory. South Dakota is the seventeenth largest by area, but the fifth smallest by population and the 5th least densely populated of the 50 United States; as the southern part of the former Dakota Territory, South Dakota became a state on November 2, 1889 with North Dakota. Pierre is the state capital and Sioux Falls, with a population of about 187,200, is South Dakota's largest city. South Dakota is bordered by the states of North Dakota, Iowa, Nebraska and Montana; the state is bisected by the Missouri River, dividing South Dakota into two geographically and distinct halves, known to residents as "East River" and "West River". Eastern South Dakota is home to most of the state's population, the area's fertile soil is used to grow a variety of crops. West of the Missouri, ranching is the predominant agricultural activity, the economy is more dependent on tourism and defense spending.
Most of the Native American reservations are in West River. The Black Hills, a group of low pine-covered mountains sacred to the Sioux, are in the southwest part of the state. Mount Rushmore, a major tourist destination, is there. South Dakota has a temperate continental climate, with four distinct seasons and precipitation ranging from moderate in the east to semi-arid in the west; the state's ecology features species typical of a North American grassland biome. Humans have inhabited the area for several millennia, with the Sioux becoming dominant by the early 19th century. In the late 19th century, European-American settlement intensified after a gold rush in the Black Hills and the construction of railroads from the east. Encroaching miners and settlers triggered a number of Indian wars, ending with the Wounded Knee Massacre in 1890. Key events in the 20th century included the Dust Bowl and Great Depression, increased federal spending during the 1940s and 1950s for agriculture and defense, an industrialization of agriculture that has reduced family farming.
While several Democratic senators have represented South Dakota for multiple terms at the federal level, the state government is controlled by the Republican Party, whose nominees have carried South Dakota in each of the last 13 presidential elections. Dominated by an agricultural economy and a rural lifestyle, South Dakota has sought to diversify its economy in areas to attract and retain residents. South Dakota's history and rural character still influence the state's culture. South Dakota is in the north-central United States, is considered a part of the Midwest by the U. S. Census Bureau; the culture and geography of western South Dakota have more in common with the West than the Midwest. South Dakota has a total area of 77,116 square miles, making the state the 17th largest in the Union. Black Elk Peak named Harney Peak, with an elevation of 7,242 ft, is the state's highest point, while the shoreline of Big Stone Lake is the lowest, with an elevation of 966 ft. South Dakota is bordered to the north by North Dakota.
The geographical center of the U. S. is 17 miles west of Castle Rock in Butte County. The North American continental pole of inaccessibility is between Allen and Kyle, 1,024 mi from the nearest coastline; the Missouri River is the longest river in the state. Other major South Dakota rivers include the Cheyenne, Big Sioux, White Rivers. Eastern South Dakota has many natural lakes created by periods of glaciation. Additionally, dams on the Missouri River create four large reservoirs: Lake Oahe, Lake Sharpe, Lake Francis Case, Lewis and Clark Lake. South Dakota can be divided into three regions: eastern South Dakota, western South Dakota, the Black Hills; the Missouri River serves as a boundary in terms of geographic and political differences between eastern and western South Dakota. The geography of the Black Hills, long considered sacred by Native Americans, differs from its surroundings to such an extent it can be considered separate from the rest of western South Dakota. At times the Black Hills are combined with the rest of western South Dakota, people refer to the resulting two regions divided by the Missouri River as West River and East River.
Eastern South Dakota features higher precipitation and lower topography than the western part of the state. Smaller geographic regions of this area include the Coteau des Prairies, the Dissected Till Plains, the James River Valley; the Coteau des Prairies is a plateau bordered on the east by the Minnesota River Valley and on the west by the James River Basin. Further west, the James River Basin is low, flat eroded land, following the flow of the James River through South Dakota from north to south; the Dissected Till Plains, an area of rolling hills and fertile soil that covers much of Iowa and Nebraska, extends into the southeastern corner of South Dakota. Layers deposited during the Pleistocene epoch, starting around two million years ago, cover most of eastern South Dakota; these are the youngest rock and sediment layers in the state, the product of several successive periods of glaciation which deposited a large amount of rocks and soil, known as till, over the area. The Great Plains cover most of the western two-thirds of South Dakota.
West of the Missouri Rive
A SQUID is a sensitive magnetometer used to measure subtle magnetic fields, based on superconducting loops containing Josephson junctions. SQUIDs are sensitive enough to measure fields as low as 5 aT with a few days of averaged measurements, their noise levels are as low as 3 fT·Hz−½. For comparison, a typical refrigerator magnet produces 0.01 tesla, some processes in animals produce small magnetic fields between 10−9 T and 10−6 T. Invented SERF atomic magnetometers are more sensitive and do not require cryogenic refrigeration but are orders of magnitude larger in size and must be operated in a near-zero magnetic field. There are two main types of SQUID: direct radio frequency. RF SQUIDs can work with only one Josephson junction, which might make them cheaper to produce, but are less sensitive; the DC SQUID was invented in 1964 by Robert Jaklevic, John J. Lambe, James Mercereau, Arnold Silver of Ford Research Labs after Brian David Josephson postulated the Josephson effect in 1962, the first Josephson junction was made by John Rowell and Philip Anderson at Bell Labs in 1963.
It has two Josephson junctions in parallel in a superconducting loop. It is based on the DC Josephson effect. In the absence of any external magnetic field, the input current I splits into the two branches equally. If a small external magnetic field is applied to the superconducting loop, a screening current, I s, begins circulating in the loop that generates a magnetic field canceling the applied external flux; the induced current is in the same direction as I in one of the branches of the superconducting loop, is opposite to I in the other branch. As soon as the current in either branch exceeds the critical current, I c, of the Josephson junction, a voltage appears across the junction. Now suppose the external flux is further increased until it exceeds Φ 0 / 2, half the magnetic flux quantum. Since the flux enclosed by the superconducting loop must be an integer number of flux quanta, instead of screening the flux the SQUID now energetically prefers to increase it to Φ 0; the current now flows in the opposite direction, opposing the difference between the admitted flux Φ 0 and the external field of just over Φ 0 / 2.
The current decreases as the external field is increased, is zero when the flux is Φ 0, again reverses direction as the external field is further increased. Thus, the current changes direction periodically, every time the flux increases by additional half-integer multiple of Φ 0, with a change at maximum amperage every half-plus-integer multiple of Φ 0 and at zero amps every integer multiple. If the input current is more than I c the SQUID always operates in the resistive mode; the voltage, in this case, is thus a function of the applied magnetic field and the period equal to Φ 0. Since the current-voltage characteristic of the DC SQUID is hysteretic, a shunt resistance, R is connected across the junction to eliminate the hysteresis; the screening current is the applied flux divided by the self-inductance of the ring. Thus Δ Φ can be estimated as the function of Δ V as follows: Δ V = R ⋅ Δ I 2 ⋅ I = 2 ⋅ Δ Φ L, where L is the self inductance of the superconducting ring Δ V = R L ⋅ Δ Φ The discussion in this Section assumed perfect flux quantization in the loop.
However, this is only true for big loops with a large self-inductance. According to the relations, given above, this implies small current and voltage variations. In practice the self-inductance L of the loop is not so large; the general case can be evaluated by introducing a parameter λ = i c L Φ 0 with i c the critical current of the SQUID. Λ is of order one. The RF SQUID was invented in 1965 by Robert Jaklevic, John J. Lambe, Arnold Silver, James Edwar
A vacuum flask is an insulating storage vessel that lengthens the time over which its contents remain hotter or cooler than the flask's surroundings. Invented by Sir James Dewar in 1892, the vacuum flask consists of two flasks, placed one within the other and joined at the neck; the gap between the two flasks is evacuated of air, creating a near-vacuum which reduces heat transfer by conduction or convection. Vacuum flasks are used domestically to keep beverages hot or cold for extended periods of time and for many purposes in industry; the vacuum flask was designed and invented by Scottish scientist Sir James Dewar in 1892 as a result of his research in the field of cryogenics and is sometimes called a Dewar flask in his honour. While performing experiments in determining the specific heat of the element palladium, Dewar made a brass chamber that he enclosed in another chamber to keep the palladium at its desired temperature, he evacuated the air between the two chambers, creating a partial vacuum to keep the temperature of the contents stable.
Through the need for this insulated container James Dewar created the vacuum flask, which became a significant tool for chemical experiments and became a common household item. The flask was developed using new materials such as glass and aluminum. Dewar's design was transformed into a commercial item in 1904 as two German glassblowers, Reinhold Burger and Albert Aschenbrenner, discovered that it could be used to keep cold drinks cold and warm drinks warm; the Dewar flask design had never been patented but the German men who discovered the commercial use for the product renamed it "Thermos," and subsequently claimed both the rights to the commercial product and the trademark to the name. In his subsequent attempt to claim the rights to the invention, Dewar instead lost a court case to the company; the manufacturing and performance of the Thermos bottle was improved and refined by the Viennese inventor and merchant Gustav Robert Paalen, who designed various types for domestic use, which he patented, distributed through his Thermos Bottle Companies in the United States and Canada.
The name became a genericized trademark after the term "thermos" became the household name for such a liquid container. The vacuum flask went on to be used for many different types of scientific experiments and the commercial "Thermos" was transformed into a common item. "Thermos" remains a registered trademark in some countries, but it was declared a genericized trademark by court action in the United States in 1963, since it had become colloquially synonymous with vacuum flasks in general. However, there are other vacuum flasks. After the German glassblowers determined the commercial uses for the Dewar flask, the technology was sold to the Thermos company, who used it to mass-produce vacuum flasks for at-home use. Over time, the company expanded the size and materials of these consumer products used for carrying coffee on the go and carrying liquids on camping trips to keep them either hot or cold. Other manufacturers produced similar products for consumer use; the vacuum flask consists of one placed within the other and joined at the neck.
The gap between the two vessels is evacuated of air, creating a partial-vacuum which reduces heat conduction or convection. Heat transfer by thermal radiation may be minimized by silvering flask surfaces facing the gap but can become problematic if the flask's contents or surroundings are hot. Most heat transfer occurs through the opening of the flask, where there is no vacuum. Vacuum flasks are made of metal, borosilicate glass, foam or plastic and have their opening stoppered with cork or polyethylene plastic. Vacuum flasks are used as insulated shipping containers. Large or long vacuum flasks sometimes cannot support the inner flask from the neck alone, so additional support is provided by spacers between the interior and exterior shell; these spacers act as a thermal bridge and reduce the insulating properties of the flask around the area where the spacer contacts the interior surface. Several technological applications, such as NMR and MRI machines, rely on the use of double vacuum flasks.
These flasks have two vacuum sections. The inner flask contains liquid helium and the outer flask contains liquid nitrogen, with one vacuum section in between; the loss of precious helium is limited in this way. Other improvements to the vacuum flask include the vapour-cooled radiation shield and the vapour-cooled neck, both of which help to reduce evaporation from the flask. In laboratories and industry, vacuum flasks are used to hold liquefied gases for flash freezing, sample preparation and other processes where maintaining an extreme low temperature is desired. Larger vacuum flasks store liquids that become gaseous at well below ambient temperature, such as oxygen and nitrogen; the insulation of the vacuum flask results in a slow "boil" and thus the contents remain liquid for long periods without refrigeration equipment. Vacuum flasks have been used to house standard cells and ovenized Zener diodes, along with their printed circuit board, in precision voltage-regulating devices used as electrical standards.
The flask helped with controlling the Z
The Smithsonian Institution, founded on August 10, 1846 "for the increase and diffusion of knowledge," is a group of museums and research centers administered by the Government of the United States. The institution is named after British scientist James Smithson. Organized as the "United States National Museum," that name ceased to exist as an administrative entity in 1967. Termed "the nation's attic" for its eclectic holdings of 154 million items, the Institution's nineteen museums, nine research centers, zoo include historical and architectural landmarks located in the District of Columbia. Additional facilities are located in Arizona, Massachusetts, New York City, Texas and Panama. More than 200 institutions and museums in 45 states, Puerto Rico, Panama are Smithsonian Affiliates; the Institution's thirty million annual visitors are admitted without charge. Its annual budget is around $1.2 billion with two-thirds coming from annual federal appropriations. Other funding comes from the Institution's endowment and corporate contributions, membership dues, earned retail and licensing revenue.
Institution publications include Air & Space magazines. The British scientist James Smithson left most of his wealth to his nephew Henry James Hungerford; when Hungerford died childless in 1835, the estate passed "to the United States of America, to found at Washington, under the name of the Smithsonian Institution, an Establishment for the increase & diffusion of knowledge among men", in accordance with Smithson's will. Congress accepted the legacy bequeathed to the nation, pledged the faith of the United States to the charitable trust on July 1, 1836; the American diplomat Richard Rush was dispatched to England by President Andrew Jackson to collect the bequest. Rush returned in August 1838 with 105 sacks containing 104,960 gold sovereigns. Once the money was in hand, eight years of Congressional haggling ensued over how to interpret Smithson's rather vague mandate "for the increase and diffusion of knowledge." The money was invested by the US Treasury in bonds issued by the state of Arkansas, which soon defaulted.
After heated debate, Massachusetts Representative John Quincy Adams persuaded Congress to restore the lost funds with interest and, despite designs on the money for other purposes, convinced his colleagues to preserve it for an institution of science and learning. On August 10, 1846, President James K. Polk signed the legislation that established the Smithsonian Institution as a trust instrumentality of the United States, to be administered by a Board of Regents and a Secretary of the Smithsonian. Though the Smithsonian's first Secretary, Joseph Henry, wanted the Institution to be a center for scientific research, it became the depository for various Washington and U. S. government collections. The United States Exploring Expedition by the U. S. Navy circumnavigated the globe between 1838 and 1842; the voyage amassed thousands of animal specimens, an herbarium of 50,000 plant specimens, diverse shells and minerals, tropical birds, jars of seawater, ethnographic artifacts from the South Pacific Ocean.
These specimens and artifacts became part of the Smithsonian collections, as did those collected by several military and civilian surveys of the American West, including the Mexican Boundary Survey and Pacific Railroad Surveys, which assembled many Native American artifacts and natural history specimens. In 1846, the regents developed a plan for weather observation; the Institution became a magnet for young scientists from 1857 to 1866, who formed a group called the Megatherium Club. The Smithsonian played a critical role as the U. S. partner institution in early bilateral scientific exchanges with the Academy of Sciences of Cuba. Construction began on the Smithsonian Institution Building in 1849. Designed by architect James Renwick Jr. its interiors were completed by general contractor Gilbert Cameron. The building opened in 1855; the Smithsonian's first expansion came with construction of the Arts and Industries Building in 1881. Congress had promised to build a new structure for the museum if the 1876 Philadelphia Centennial Exposition generated enough income.
It did, the building was designed by architects Adolf Cluss and Paul Schulze, based on original plans developed by Major General Montgomery C. Meigs of the United States Army Corps of Engineers, it opened in 1881. The National Zoological Park opened in 1889 to accommodate the Smithsonian's Department of Living Animals; the park was designed by landscape architect Frederick Law Olmsted. The National Museum of Natural History opened in June 1911 to accommodate the Smithsonian's United States National Museum, housed in the Castle and the Arts and Industries Building; this structure was designed by the D. C. architectural firm of Hornblower & Marshall. When Detroit philanthropist Charles Lang Freer donated his private collection to the Smithsonian and funds to build the museum to hold it, it was among the Smithsonian's first major donations from a private individual; the gallery opened in 1923. More than 40 years would pass before the next museum, the Museum of History and Technology, opened in 1964.
It was designed by the world-renowned firm of Mead & White. The Anacostia Community Museum, an "experimental store-front" museum created at the initiative of Smithsonian Secretary S. Dillon Ripley, opened in the Anacostia neighborhood of
Carnegie Mellon University
Carnegie Mellon University is a private research university based in Pittsburgh, Pennsylvania. Founded in 1900 by Andrew Carnegie as the Carnegie Technical Schools, the university became the Carnegie Institute of Technology in 1912 and began granting four-year degrees. In 1967, the Carnegie Institute of Technology merged with the Mellon Institute of Industrial Research to form Carnegie Mellon University. With its main campus located 3 miles from Downtown Pittsburgh, Carnegie Mellon has grown into an international university with over a dozen degree-granting locations in six continents, including campuses in Qatar and Silicon Valley, more than 20 research partnerships; the university has seven colleges and independent schools which all offer interdisciplinary programs: the College of Engineering, College of Fine Arts, Dietrich College of Humanities and Social Sciences, Mellon College of Science, Tepper School of Business, H. John Heinz III College of Information Systems and Public Policy, the School of Computer Science.
Carnegie Mellon counts 13,961 students from 109 countries, over 105,000 living alumni, over 5,000 faculty and staff. Past and present faculty and alumni include 20 Nobel Prize laureates, 13 Turing Award winners, 23 Members of the American Academy of Arts and Sciences, 22 Fellows of the American Association for the Advancement of Science, 79 Members of the National Academies, 124 Emmy Award winners, 47 Tony Award laureates, 10 Academy Award winners; the Carnegie Technical Schools were founded in 1900 in Pittsburgh by the Scottish American industrialist and philanthropist Andrew Carnegie, who wrote the time-honored words "My heart is in the work", when he donated the funds to create the institution. Carnegie's vision was to open a vocational training school for the sons and daughters of working-class Pittsburghers. Carnegie was inspired for the design of his school by the Pratt Institute in Brooklyn, New York founded by industrialist Charles Pratt in 1887. In 1912, the institution changed its name to Carnegie Institute of Technology and began offering four-year degrees.
During this time, CIT consisted of four constituent schools: the School of Fine and Applied Arts, the School of Apprentices and Journeymen, the School of Science and Technology, the Margaret Morrison Carnegie School for Women. The Mellon Institute of Industrial Research was founded in 1913 by a banker and industrialist brothers Andrew and Richard B. Mellon in honor of their father, Thomas Mellon, the patriarch of the Mellon family; the Institute began as a research organization which performed work for government and industry on a contract and was established as a department within the University of Pittsburgh. In 1927, the Mellon Institute incorporated as an independent nonprofit. In 1938, the Mellon Institute's iconic building was completed and it moved to its new, current, location on Fifth Avenue. In 1967, with support from Paul Mellon, Carnegie Tech merged with the Mellon Institute of Industrial Research to become Carnegie Mellon University. Carnegie Mellon's coordinate women's college, the Margaret Morrison Carnegie College closed in 1973 and merged its academic programs with the rest of the university.
The industrial research mission of the Mellon Institute survived the merger as the Carnegie Mellon Research Institute and continued doing work on contract to industry and government. CMRI closed in 2001 and its programs were subsumed by other parts of the university or spun off into autonomous entities. Carnegie Mellon's 140-acre main campus is three miles from downtown Pittsburgh, between Schenley Park and the Squirrel Hill and Oakland neighborhoods. Carnegie Mellon is bordered to the west by the campus of the University of Pittsburgh. Carnegie Mellon owns 81 buildings in the Squirrel Hill neighborhoods of Pittsburgh. For decades the center of student life on campus was the University's student union. Built in the 1950s, Skibo Hall's design was typical of Mid-Century Modern architecture, but was poorly equipped to deal with advances in computer and internet connectivity; the original Skibo was razed in the summer of 1994 and replaced by a new student union, wi-fi enabled. Known as University Center, the building was dedicated in 1996.
In 2014, Carnegie Mellon re-dedicated the University Center as the Cohon University Center in recognition of the eighth president of the university, Jared Cohon. A large grassy area known as "the Cut" forms the backbone of the campus, with a separate grassy area known as "the Mall" running perpendicular; the Cut was formed by filling in a ravine with soil from a nearby hill, leveled to build the College of Fine Arts building. The northwestern part of the campus was acquired from the United States Bureau of Mines in the 1980s. In 2006, Carnegie Mellon Trustee Jill Gansman Kraus donated the 80-foot -tall sculpture Walking to the Sky, placed on the lawn facing Forbes Ave between the Cohon University Center and Warner Hall; the sculpture was controversial for its placement, the general lack of input that the campus community had, its aesthetic appeal. In April 2015, Carnegie Mellon University, in collaboration with Jones Lang LaSalle, announced the planning of a second office space structure, alongside the Robert Mehrabian Collaborative Innovation Center, an upscale and full-service hotel, retail and dining development along Forbes Avenue.
This complex will connect to the Tepper Quadrangle, the Heinz College, the Tata Consultancy Services Building, the Gates-Hillman Center to create an innovation corridor on the university campus. The eff
Superconductivity is a phenomenon of zero electrical resistance and expulsion of magnetic flux fields occurring in certain materials, called superconductors, when cooled below a characteristic critical temperature. It was discovered by Dutch physicist Heike Kamerlingh Onnes on April 1911, in Leiden. Like ferromagnetism and atomic spectral lines, superconductivity is a quantum mechanical phenomenon, it is characterized by the Meissner effect, the complete ejection of magnetic field lines from the interior of the superconductor during its transitions into the superconducting state. The occurrence of the Meissner effect indicates that superconductivity cannot be understood as the idealization of perfect conductivity in classical physics; the electrical resistance of a metallic conductor decreases as temperature is lowered. In ordinary conductors, such as copper or silver, this decrease is limited by impurities and other defects. Near absolute zero, a real sample of a normal conductor shows some resistance.
In a superconductor, the resistance drops abruptly to zero when the material is cooled below its critical temperature. An electric current through a loop of superconducting wire can persist indefinitely with no power source. In 1986, it was discovered that some cuprate-perovskite ceramic materials have a critical temperature above 90 K; such a high transition temperature is theoretically impossible for a conventional superconductor, leading the materials to be termed high-temperature superconductors. The cheaply-available coolant liquid nitrogen boils at 77 K, thus superconduction at higher temperatures than this facilitates many experiments and applications that are less practical at lower temperatures. There are many criteria; the most common are: A superconductor can be Type I, meaning it has a single critical field, above which all superconductivity is lost and below which the magnetic field is expelled from the superconductor. These points are called vortices. Furthermore, in multicomponent superconductors it is possible to have combination of the two behaviours.
In that case the superconductor is of Type-1.5. It is conventional if it can be explained by the BCS theory or its derivatives, or unconventional, otherwise. A superconductor is considered high-temperature if it reaches a superconducting state when cooled using liquid nitrogen – that is, at only Tc > 77 K) – or low-temperature if more aggressive cooling techniques are required to reach its critical temperature. Superconductor material classes include chemical elements, ceramics, superconducting pnictides or organic superconductors. Most of the physical properties of superconductors vary from material to material, such as the heat capacity and the critical temperature, critical field, critical current density at which superconductivity is destroyed. On the other hand, there is a class of properties. For instance, all superconductors have zero resistivity to low applied currents when there is no magnetic field present or if the applied field does not exceed a critical value; the existence of these "universal" properties implies that superconductivity is a thermodynamic phase, thus possesses certain distinguishing properties which are independent of microscopic details.
The simplest method to measure the electrical resistance of a sample of some material is to place it in an electrical circuit in series with a current source I and measure the resulting voltage V across the sample. The resistance of the sample is given by Ohm's law as R = V / I. If the voltage is zero, this means. Superconductors are able to maintain a current with no applied voltage whatsoever, a property exploited in superconducting electromagnets such as those found in MRI machines. Experiments have demonstrated that currents in superconducting coils can persist for years without any measurable degradation. Experimental evidence points to a current lifetime of at least 100,000 years. Theoretical estimates for the lifetime of a persistent current can exceed the estimated lifetime of the universe, depending on the wire geometry and the temperature. In practice, currents injected in superconducting coils have persisted for more than 23 years in superconducting gravimeters. In such instruments, the measurement principle is based on the monitoring of the levitation of a superconducting niobium sphere with a mass of 4 grams.
In a normal conductor, an electric current may be visualized as a fluid of electrons moving across a heavy ionic lattice. The electrons are colliding with the ions in the lattice, during each collision some of the energy carried by the current is absorbed by the lattice and converted into heat, the vibrational kinetic energy of the lattice ions; as a result, the energy carried by the current is being dissipated. This is the phenomenon of electrical Joule heating; the situation is different in a superconductor. In a conventional superconductor, the electronic fluid cannot be resolved into individual electrons. Instead, it consists of bound pairs of electrons known as Cooper pairs; this pairing is caused by an attractive force between electrons from the exchange of phonons. Due to quantum mechanics, the energy spectr