Clinton Joseph Davisson was an American physicist who won the 1937 Nobel Prize in Physics for his discovery of electron diffraction in the famous Davisson-Germer experiment. Davisson shared the Nobel Prize with George Paget Thomson, who independently discovered electron diffraction at about the same time as Davisson. Davisson was born in Illinois, he graduated from Bloomington High School in 1902, entered the University of Chicago on scholarship. Upon the recommendation of Robert A. Millikan, in 1905 Davisson was hired by Princeton University as Instructor of Physics, he completed the requirements for his B. S. degree from Chicago in 1908 by working in the summers. While teaching at Princeton, he did doctoral thesis research with Owen Richardson, he received his Ph. D. in physics from Princeton in 1911. Davisson was appointed as an assistant professor at the Carnegie Institute of Technology. In 1917 he took a leave from the Carnegie Institute to do war-related research with the Engineering Department of the Western Electric Company.
At the end of the war, Davisson accepted a permanent position at Western Electric after receiving assurances of his freedom there to do basic research. He had found that his teaching responsibilities at the Carnegie Institute precluded him from doing research. Davisson remained at Western Electric until his formal retirement in 1946, he accepted a research professor appointment at the University of Virginia that continued until his second retirement in 1954. Electron Diffraction and the Davisson-Germer ExperimentDiffraction is a characteristic effect when a wave is incident upon an aperture or a grating, is associated with the meaning of wave motion itself. In the 19th Century, diffraction was well established for light and for ripples on the surfaces of fluids. In 1927, while working for Bell Labs and Lester Germer performed an experiment showing that electrons were diffracted at the surface of a crystal of nickel; this celebrated Davisson-Germer experiment confirmed the de Broglie hypothesis that particles of matter have a wave-like nature, a central tenet of quantum mechanics.
In particular, their observation of diffraction allowed the first measurement of a wavelength for electrons. The measured wavelength λ agreed well with de Broglie's equation λ = h / p, where h is Planck's constant and p is the electron's momentum. While doing his graduate work at Princeton, Davisson met his wife and life companion Charlotte Sara Richardson, visiting her brother, Professor Richardson. Richardson is the sister-in-law of Oswald Veblen, a prominent mathematician. Clinton and Charlotte Davisson had the American physicist Richard Davisson; the crater Davisson on the Moon is named after him. Davisson died on February 1, 1958, at the age of 76. An impact crater on the far side of the moon was named after Davisson in 1970 by the IAU. Nobelprize.org Biography Bloomington native won Nobel Prize in physics - Pantagraph
Corpus Christi College, Cambridge
Corpus Christi College is a constituent college of the University of Cambridge. It is notable as the only college founded by Cambridge townspeople: it was established in 1352 by the Guild of Corpus Christi and the Guild of the Blessed Virgin Mary, making it the sixth-oldest college in Cambridge. With around 250 undergraduates and 200 postgraduates, it has the second smallest student body of the traditional colleges of the University; the College has traditionally been one of the more academically successful colleges in the University of Cambridge. In the unofficial Tompkins Table, which ranks the colleges by the class of degrees obtained by their undergraduates, Corpus's 2012 position was 3rd, with 32.4% of its undergraduates achieving first-class results. The college's average position between 2003 and 2012 was 9th, in the most recent rankings, it was placed 10th. Corpus ranks among the wealthiest Cambridge colleges in terms of fixed assets, being exceptionally rich in silver; the College's endowment was valued at £90.9M at the end of June 2017, while its net assets were valued at £227.4M.
The guild of Corpus Christi was founded in Cambridge in 1349 by William Horwode, Henry de Tangmere, John Hardy in response to the Black Death. They determined to found a new college in the University of Cambridge, the sixth in the University's history; the same year the new guild merged with an older guild, the Guild of the Blessed Virgin Mary, decimated by the Plague. The united guilds acquired land in the centre of town and their patron, the Duke of Lancaster, applied to King Edward III for a licence to found a new college, granted in 1352. Construction began of a single modest court near the parish church and in 1356 it was ready to house the Master and two fellows; the college's statutes were drawn up in 1356. The united guild merged its identity with the new college, which acquired all the guild's lands and revenues; the grandest of these ceremonies was the annual Corpus Christi procession: a parade through the streets to Magdalene Bridge, the host carried by a priest and several of the college's treasures carried by the Master and fellows, before returning for an extravagant dinner.
The parade continued until the English Reformation, when the Master, William Sowode, put a stop to it in 1535. The college continues to have a grand dinner on the feast day of Corpus Christi, the Thursday after Trinity Sunday; the newly constructed court could house 22 students. The statutes laid down the rules governing the behaviour of fellows only. Students were not part of the foundation at this stage and would not come within the scope of the statutes for another 200 years. In its early centuries, the college was poor and so could not construct new buildings, it had no chapel, so the members worshipped in St Bene't's Church next door. From the late 14th century through to the 19th century during the Reformation when Catholic references were discouraged, Corpus was known as St Benet's College. By 1376 it possessed 55 books, many more would be donated or bequeathed over the succeeding centuries, most those donated in the 16th century by Archbishop Matthew Parker, celebrated by the college as its greatest benefactor.
During the Peasants' Revolt in 1381, the college was sacked by a mob of townspeople led by the mayor which, according to the college, carried away its plate as well as its charter to be burned while gutting the rest of the college buildings. Corpus was the only University college, although by no means the only University building, to be attacked; the revolt, which took place during the Corpus Christi week, focused on the college as centre of discontent due to its rigid collection of "candle rents". The college claimed £80 in damages. In 1460 during the Wars of the Roses, the college paid for armaments including artillery and arrows, protective clothing to defend the college's treasures from a "tempestuous riot". Elizabeth, Duchess of Norfolk, her sister Lady Eleanor Botelar née Talbot, believed by some to have been secretly married to Edward IV, endowed the college with scholarships in the 1460s and financed repairs to the college buildings; as a monument a'talbot', the heraldic supporter of the Talbot family, was placed on the gable of Old Court and can still be seen today.
At the same time the Master, Thomas Cosyn, built the college's first chapel and a passageway between Old Court and St Bene't's Church. Over the next few centuries, garret rooms were added in Old Court increasing student numbers. Although spared the worst of the religious tumult that the Reformation brought to England, the college produced adherents and indeed martyrs to both traditions. Notable are William Sowode who cancelled the Corpus Christi procession, St Richard Reynolds, martyred by Henry VIII and Thomas Dusgate and George Wishart who were both burned as Protestants, it was during this time. He donated his unrivalled library to much silver plate and its symbol, the pelican. In order to ensure the safety of his collection Parker inserted into the terms of his endowment one which stated that if any more than a certain number of books were lost, the rest of the collection would pass first to Gonville and Caius College, Cambridge and to Trinity Hall, Cambridge; every few years, representatives from both of those colleges ceremonially inspect the collection for any losses.
Parker placed a similar condition on the silv
Captain (armed forces)
The army rank of captain is a commissioned officer rank corresponding to the command of a company of soldiers. The rank is used by some air forces and marine forces. Today, a captain is either the commander or second-in-command of a company or artillery battery. In the Chinese People's Liberation Army, a captain may command a company, or be the second-in-command of a battalion. In NATO countries, the rank of captain is described by the code OF-2 and is one rank above an OF-1 and one below an OF-3; the rank of captain is considered to be the highest rank a soldier can achieve while remaining in the field. In some militaries, such as United States Army and Air Force and the British Army, captain is the entry-level rank for officer candidates possessing a professional degree, most medical professionals and lawyers. In the U. S.. Army, lawyers who are not officers at captain rank or above enter as lieutenants during training, are promoted to the rank of captain after completion of their training if they are in the active component, or after a certain amount of time one year from their date of commission as a lieutenant, for the reserve components.
The rank of captain should not be confused with the naval rank of captain or with the UK-influenced air force rank of group captain, both of which are equivalent to the army rank of colonel. The term goes back to Late Latin capitaneus meaning "chief, prominent"; the military rank of captain was in use from the 1560s, referring to an officer who commands a company. The naval sense, an officer who commands a man-of-war, is somewhat earlier, from the 1550s extended in meaning to "master or commander of any kind of vessel". A captain in the period prior to the professionalization of the armed services of European nations subsequent to the French Revolution, during the early modern period, was a nobleman who purchased the right to head a company from the previous holder of that right, he would in turn receive money from another nobleman to serve as his lieutenant. The funding to provide for the troops came from his government. If he was not, or was otherwise court-martialed, he would be dismissed, the monarch would receive money from another nobleman to command the company.
Otherwise, the only pension for the captain was selling the right to another nobleman when he was ready to retire. Many air forces, such as the United States Air Force, use a rank structure and insignia similar to those of the army. However, the United Kingdom's Royal Air Force, many other Commonwealth air forces and a few non-Commonwealth air forces use an air force-specific rank structure in which flight lieutenant is OF-2. A group captain was derived from the naval rank of captain. In the unified system of the Canadian Forces, the air force rank titles are pearl grey and increase from OF-1 to OF-5 in half strip increments. A variety of images illustrative of different forces' insignia for captain are shown below: Captain Captain Senior captain Staff captain
The electron is a subatomic particle, symbol e− or β−, whose electric charge is negative one elementary charge. Electrons belong to the first generation of the lepton particle family, are thought to be elementary particles because they have no known components or substructure; the electron has a mass, 1/1836 that of the proton. Quantum mechanical properties of the electron include an intrinsic angular momentum of a half-integer value, expressed in units of the reduced Planck constant, ħ; as it is a fermion, no two electrons can occupy the same quantum state, in accordance with the Pauli exclusion principle. Like all elementary particles, electrons exhibit properties of both particles and waves: they can collide with other particles and can be diffracted like light; the wave properties of electrons are easier to observe with experiments than those of other particles like neutrons and protons because electrons have a lower mass and hence a longer de Broglie wavelength for a given energy. Electrons play an essential role in numerous physical phenomena, such as electricity, magnetism and thermal conductivity, they participate in gravitational and weak interactions.
Since an electron has charge, it has a surrounding electric field, if that electron is moving relative to an observer, it will generate a magnetic field. Electromagnetic fields produced from other sources will affect the motion of an electron according to the Lorentz force law. Electrons absorb energy in the form of photons when they are accelerated. Laboratory instruments are capable of trapping individual electrons as well as electron plasma by the use of electromagnetic fields. Special telescopes can detect electron plasma in outer space. Electrons are involved in many applications such as electronics, cathode ray tubes, electron microscopes, radiation therapy, gaseous ionization detectors and particle accelerators. Interactions involving electrons with other subatomic particles are of interest in fields such as chemistry and nuclear physics; the Coulomb force interaction between the positive protons within atomic nuclei and the negative electrons without, allows the composition of the two known as atoms.
Ionization or differences in the proportions of negative electrons versus positive nuclei changes the binding energy of an atomic system. The exchange or sharing of the electrons between two or more atoms is the main cause of chemical bonding. In 1838, British natural philosopher Richard Laming first hypothesized the concept of an indivisible quantity of electric charge to explain the chemical properties of atoms. Irish physicist George Johnstone Stoney named this charge'electron' in 1891, J. J. Thomson and his team of British physicists identified it as a particle in 1897. Electrons can participate in nuclear reactions, such as nucleosynthesis in stars, where they are known as beta particles. Electrons can be created through beta decay of radioactive isotopes and in high-energy collisions, for instance when cosmic rays enter the atmosphere; the antiparticle of the electron is called the positron. When an electron collides with a positron, both particles can be annihilated, producing gamma ray photons.
The ancient Greeks noticed. Along with lightning, this phenomenon is one of humanity's earliest recorded experiences with electricity. In his 1600 treatise De Magnete, the English scientist William Gilbert coined the New Latin term electrica, to refer to those substances with property similar to that of amber which attract small objects after being rubbed. Both electric and electricity are derived from the Latin ēlectrum, which came from the Greek word for amber, ἤλεκτρον. In the early 1700s, Francis Hauksbee and French chemist Charles François du Fay independently discovered what they believed were two kinds of frictional electricity—one generated from rubbing glass, the other from rubbing resin. From this, du Fay theorized that electricity consists of two electrical fluids and resinous, that are separated by friction, that neutralize each other when combined. American scientist Ebenezer Kinnersley also independently reached the same conclusion. A decade Benjamin Franklin proposed that electricity was not from different types of electrical fluid, but a single electrical fluid showing an excess or deficit.
He gave them the modern charge nomenclature of negative respectively. Franklin thought of the charge carrier as being positive, but he did not identify which situation was a surplus of the charge carrier, which situation was a deficit. Between 1838 and 1851, British natural philosopher Richard Laming developed the idea that an atom is composed of a core of matter surrounded by subatomic particles that had unit electric charges. Beginning in 1846, German physicist William Weber theorized that electricity was composed of positively and negatively charged fluids, their interaction was governed by the inverse square law. After studying the phenomenon of electrolysis in 1874, Irish physicist George Johnstone Stoney suggested that there existed a "single definite quantity of electricity", the charge of a monovalent ion, he was able to estimate the value of this elementary charge e by means of Faraday's laws of electrolysis. However, Stoney could not be removed. In 1881, German physicist Hermann von Helmholtz argued that both positive and negative charges were divided into elementary parts, each of which "behaves like atoms of electricity".
Stoney coined the term
Cornell University is a private and statutory Ivy League research university in Ithaca, New York. Founded in 1865 by Ezra Cornell and Andrew Dickson White, the university was intended to teach and make contributions in all fields of knowledge—from the classics to the sciences, from the theoretical to the applied; these ideals, unconventional for the time, are captured in Cornell's founding principle, a popular 1868 Ezra Cornell quotation: "I would found an institution where any person can find instruction in any study."The university is broadly organized into seven undergraduate colleges and seven graduate divisions at its main Ithaca campus, with each college and division defining its own admission standards and academic programs in near autonomy. The university administers two satellite medical campuses, one in New York City and one in Education City and Cornell Tech, a graduate program that incorporates technology and creative thinking; the program moved from Google's Chelsea Building in New York City to its permanent campus on Roosevelt Island in September 2017.
Cornell is one of ten private land grant universities in the United States and the only one in New York. Of its seven undergraduate colleges, three are state-supported statutory or contract colleges through the State University of New York system, including its agricultural and human ecology colleges as well as its industrial labor relations school. Of Cornell's graduate schools, only the veterinary college is state-supported; as a land grant college, Cornell operates a cooperative extension outreach program in every county of New York and receives annual funding from the State of New York for certain educational missions. The Cornell University Ithaca Campus comprises 745 acres, but is much larger when the Cornell Botanic Gardens and the numerous university-owned lands in New York City are considered; as of October 2018, 58 Nobel laureates, four Turing Award winners and one Fields Medalist have been affiliated with Cornell University. Since its founding, Cornell has been a co-educational, non-sectarian institution where admission has not been restricted by religion or race.
Cornell counts more than 245,000 living alumni, its former and present faculty and alumni include 34 Marshall Scholars, 30 Rhodes Scholars, 29 Truman Scholars, 7 Gates Scholars, 55 Olympic Medalists, 14 living billionaires. The student body consists of more than 14,000 undergraduate and 8,000 graduate students from all 50 American states and 116 countries. Cornell University was founded on April 27, 1865. Senator Ezra Cornell offered his farm in Ithaca, New York, as a site and $500,000 of his personal fortune as an initial endowment. Fellow senator and educator Andrew Dickson White agreed to be the first president. During the next three years, White oversaw the construction of the first two buildings and traveled to attract students and faculty; the university was inaugurated on October 7, 1868, 412 men were enrolled the next day. Cornell developed as a technologically innovative institution, applying its research to its own campus and to outreach efforts. For example, in 1883 it was one of the first university campuses to use electricity from a water-powered dynamo to light the grounds.
Since 1894, Cornell fulfill statutory requirements. Cornell has had active alumni since its earliest classes, it was one of the first universities to include alumni-elected representatives on its Board of Trustees. Cornell was among the Ivies that had heightened student activism during the 1960s related to cultural issues, civil rights, opposition to the Vietnam War. Today the university has more than 4,000 courses. Cornell is known for the Residential Club Fire of 1967, a fire in the Residential Club building that killed eight students and one professor. Since 2000, Cornell has been expanding its international programs. In 2004, the university opened the Weill Cornell Medical College in Qatar, it has partnerships with institutions in India and the People's Republic of China. Former president Jeffrey S. Lehman described the university, with its high international profile, a "transnational university". On March 9, 2004, Cornell and Stanford University laid the cornerstone for a new'Bridging the Rift Center' to be built and jointly operated for education on the Israel–Jordan border.
Cornell's main campus is on East Hill in Ithaca, New York, overlooking Cayuga Lake. Since the university was founded, it has expanded to about 2,300 acres, encompassing both the hill and much of the surrounding areas. Central Campus has laboratories, administrative buildings, all of the campus' academic buildings, athletic facilities and museums. North Campus is composed of ten residence halls that house first-year students, although the Townhouse Community houses transfer students; the five main residence halls on West Campus make up the West Campus House System, along with several Gothic-style buildings, referred to as "the Gothics". Collegetown contains two upper-level residence halls and the Schwartz Performing Arts Center amid a mixed-use neighborhood of apartments and businesses; the main campus is marked by an irregular layout and eclectic architectural styles, including ornate Collegiate Gothic and Neoclassical buildings, the more spare international and modernist structures. The more ornat
Leckhampton, Corpus Christi College, Cambridge
Leckhampton is the residential site for postgraduate students of Corpus Christi College of the University of Cambridge, England. It consists of the late-19th-century Leckhampton House, the George Thomson Building, dating from the 1960s, several other nearby houses. In 2012, a new, purpose-built accommodation building was built to house additional students; the new building was opened on 14 September 2012 by the College Visitor and Chancellor of the University, David Sainsbury. The buildings are set off Grange Road in the west of Cambridge amidst large, attractive gardens adjacent to Corpus's sports grounds, about fifteen minutes' walk from the main college site in Trumpington Street. Leckhampton has dining hall and bar, it houses a number of fellows, both visiting and of Corpus. Removed from the city centre, yet close to many academic buildings including the University Library and the Sidgwick Site, Leckhampton is in a convenient location for graduate students, was a pioneering development among Cambridge colleges when it was established as a graduate centre.
Prior to this, graduate students at Cambridge, long a tiny minority of the student body, had for the most part lived among undergraduates in colleges' main sites. Corpus's response to the growing number of graduate students in the 1960s was to establish at Leckhampton a self-contained graduate community, a move which has since been emulated to some extent by many other colleges. Although at least one of these developments went much further than Leckhampton – Clare College's graduate site became the independent college of Clare Hall in 1984. Since the separation of Clare and Clare Hall, it is once again unique among the colleges that admit both undergraduates and postgraduates in having a dedicated graduate site; the interests of Leckhampton are represented by the Warden of Leckhampton, a senior Fellow of the College. The Warden has rooms in Leckhampton House, hosts a number of social functions at Leckhampton throughout the year; the current Warden is John David Rhodes, who lectures on European and American cinema in the Faculty of Modern and Medieval Languages.
Leckhampton House was designed by the architect William C. Marshall in 1881 for its first inhabitants, Frederic W. H. Myers and Eveleen Tennant. Frederic Myers was a classical scholar, poet and founder of the Society for Psychical Research. Eveleen Tennant Myers was a talented amateur photographer whose collection is displayed at the National Portrait Gallery, including many photographs of Leckhampton House. In contrast to Leckhampton House's suburban late-Victorianism, the George Thomson Building is Grade II listed example of postwar modernism, designed by Philip Dowson of Arup Associates. Like other buildings of its kind on University campuses, some have criticised it as unimaginative and out of place. Others, have hailed it as an outstanding example for the period; the other buildings of Leckhampton are late-nineteenth-century houses in the adjacent streets which have been bought by the college over the years and linked to the main buildings and gardens, a new building opened in September 2012.
David Ibbetson James Buxton Dr John David Rhodes
Aerodynamics, from Greek ἀήρ aer + δυναμική, is the study of motion of air as interaction with a solid object, such as an airplane wing. It is a sub-field of fluid dynamics and gas dynamics, many aspects of aerodynamics theory are common to these fields; the term aerodynamics is used synonymously with gas dynamics, the difference being that "gas dynamics" applies to the study of the motion of all gases, is not limited to air. The formal study of aerodynamics began in the modern sense in the eighteenth century, although observations of fundamental concepts such as aerodynamic drag were recorded much earlier. Most of the early efforts in aerodynamics were directed toward achieving heavier-than-air flight, first demonstrated by Otto Lilienthal in 1891. Since the use of aerodynamics through mathematical analysis, empirical approximations, wind tunnel experimentation, computer simulations has formed a rational basis for the development of heavier-than-air flight and a number of other technologies.
Recent work in aerodynamics has focused on issues related to compressible flow and boundary layers and has become computational in nature. Modern aerodynamics only dates back to the seventeenth century, but aerodynamic forces have been harnessed by humans for thousands of years in sailboats and windmills, images and stories of flight appear throughout recorded history, such as the Ancient Greek legend of Icarus and Daedalus. Fundamental concepts of continuum and pressure gradients appear in the work of Aristotle and Archimedes. In 1726, Sir Isaac Newton became the first person to develop a theory of air resistance, making him one of the first aerodynamicists. Dutch-Swiss mathematician Daniel Bernoulli followed in 1738 with Hydrodynamica in which he described a fundamental relationship between pressure and flow velocity for incompressible flow known today as Bernoulli's principle, which provides one method for calculating aerodynamic lift. In 1757, Leonhard Euler published the more general Euler equations which could be applied to both compressible and incompressible flows.
The Euler equations were extended to incorporate the effects of viscosity in the first half of the 1800s, resulting in the Navier–Stokes equations. The Navier-Stokes equations are the most general governing equations of fluid flow and but are difficult to solve for the flow around all but the simplest of shapes. In 1799, Sir George Cayley became the first person to identify the four aerodynamic forces of flight, as well as the relationships between them, in doing so outlined the path toward achieving heavier-than-air flight for the next century. In 1871, Francis Herbert Wenham constructed the first wind tunnel, allowing precise measurements of aerodynamic forces. Drag theories were developed by Jean le Rond d'Alembert, Gustav Kirchhoff, Lord Rayleigh. In 1889, Charles Renard, a French aeronautical engineer, became the first person to reasonably predict the power needed for sustained flight. Otto Lilienthal, the first person to become successful with glider flights, was the first to propose thin, curved airfoils that would produce high lift and low drag.
Building on these developments as well as research carried out in their own wind tunnel, the Wright brothers flew the first powered airplane on December 17, 1903. During the time of the first flights, Frederick W. Lanchester, Martin Kutta, Nikolai Zhukovsky independently created theories that connected circulation of a fluid flow to lift. Kutta and Zhukovsky went on to develop a two-dimensional wing theory. Expanding upon the work of Lanchester, Ludwig Prandtl is credited with developing the mathematics behind thin-airfoil and lifting-line theories as well as work with boundary layers; as aircraft speed increased, designers began to encounter challenges associated with air compressibility at speeds near or greater than the speed of sound. The differences in air flows under such conditions leads to problems in aircraft control, increased drag due to shock waves, the threat of structural failure due to aeroelastic flutter; the ratio of the flow speed to the speed of sound was named the Mach number after Ernst Mach, one of the first to investigate the properties of supersonic flow.
William John Macquorn Rankine and Pierre Henri Hugoniot independently developed the theory for flow properties before and after a shock wave, while Jakob Ackeret led the initial work of calculating the lift and drag of supersonic airfoils. Theodore von Kármán and Hugh Latimer Dryden introduced the term transonic to describe flow speeds around Mach 1 where drag increases rapidly; this rapid increase in drag led aerodynamicists and aviators to disagree on whether supersonic flight was achievable until the sound barrier was broken for the first time in 1947 using the Bell X-1 aircraft. By the time the sound barrier was broken, aerodynamicists' understanding of the subsonic and low supersonic flow had matured; the Cold War prompted the design of an ever-evolving line of high performance aircraft. Computational fluid dynamics began as an effort to solve for flow properties around complex objects and has grown to the point where entire aircraft can be designed using computer software, with wind-tunnel tests followed by flight tests to confirm the computer predictions.
Understanding of supersonic and hypersonic aerodynamics has matured since the 1960s, the goals of aerodynamicists have shifted from the behavior of fluid flow to the engineering of a vehicle such that it interacts pedictably with the fluid flow. Designing aircraft for supersonic and hypersonic conditions, as well as the desire to improve the aerodynamic efficiency of current aircraft and propulsion systems, continues to motivate new research in aero