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Albert W. Hull
Albert Wallace Hull (19 April 1880 – 22 January 1966) was an American physicist and electrical engineer who made contributions to the development of vacuum tubes, and invented the magnetron. He was a member of the National Academy of Sciences. Biography He was born on 19 April 1880 in Southington, Connecticut. He majored in Greek and after taking one undergraduate course in physics, graduated from Yale University. He taught languages at The Albany Academy before returning to Yale, to take a doctorate in physics. He then undertook research on photoelectricity whilst teaching physics for five years at the Worcester Polytechnic Institute. In 1914 Hull joined the General Electric Research Laboratory (GERL) in Schenectady, New York and remained there until his retirement in 1949. During 1916, Hull began investigation into the use of magnetic control of thermionic valves (vacuum tubes) as an alternative to grid or electrostatic control and he had tested successfully magneti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Southington, Connecticut
Southington is a town in Hartford County, Connecticut, United States. As of the 2020 United States Census, it had a population of 43,501. Southington contains the villages of Marion, Milldale, and Plantsville. Geography Southington is situated about southwest of Hartford, about northeast of New York City, southwest of Boston and west of Providence. It includes the areas of Plantsville, Marion and Milldale, each of which has its own post office and distinct architecture. The town rests in a valley of two mountains on its east and west sides. The town is located along exits 28 through 32 of Interstate 84, exit 4 of Interstate 691, and bisected by Connecticut Route 10. Southington has the nickname of "The Apple Valley", due to the many orchards that still dot its landscape. The Quinnipiac River flows through the town. It is home to Mount Southington ski area, which has drawn visitors since the 1960s. Southington is located at geographical coordinates 41° 35′ 48" North ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
General Electric
General Electric Company (GE) is an American multinational conglomerate founded in 1892, and incorporated in New York state and headquartered in Boston. The company operated in sectors including healthcare, aviation, power, renewable energy, digital industry, additive manufacturing and venture capital and finance, but has since divested from several areas, now primarily consisting of the first four segments. In 2020, GE ranked among the Fortune 500 as the 33rd largest firm in the United States by gross revenue. In 2011, GE ranked among the Fortune 20 as the 14th most profitable company, but later very severely underperformed the market (by about 75%) as its profitability collapsed. Two employees of GE – Irving Langmuir (1932) and Ivar Giaever (1973) – have been awarded the Nobel Prize. On November 9, 2021, the company announced it would divide itself into three investment-grade public companies. On July 18, 2022, GE unveiled the brand names of the companies it will ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Harry Boot
Henry Albert Howard Boot (29 July 1917 – 8 February 1983) was an English physicist who with Sir John Randall and James Sayers developed the cavity magnetron, which was one of the keys to the Allied victory in the Second World War. Biography Henry Boot was born in Birmingham and attended King Edward's School, Birmingham and the University of Birmingham. While working on his PhD the war broke out. His professor Mark Oliphant had seen the klystron at Stanford University but it produced insufficient power to be useful as a radar transmitter. He assigned John Randall and Boot to the problem. By late February 1940, they had invented the much more powerful cavity magnetron which was fitted in an experimental radar by May 1940. James Sayers later refined the magnetron still further by strapping alternate cavities. As with many British inventions of this period, the magnetron was provided to the US for free when they entered World War II. Initially Boot and Randall were awarded ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
John Randall (physicist)
Sir John Turton Randall, (23 March 1905 – 16 June 1984) was an English physicist and biophysicist, credited with radical improvement of the cavity magnetron, an essential component of centimetric wavelength radar, which was one of the keys to the Allied victory in the Second World War. It is also the key component of microwave ovens. Randall collaborated with Harry Boot, and they produced a valve that could spit out pulses of microwave radio energy on a wavelength of 10 cm. On the significance of their invention, Professor of military history at the University of Victoria in British Columbia, David Zimmerman, states: "The magnetron remains the essential radio tube for shortwave radio signals of all types. It not only changed the course of the war by allowing us to develop airborne radar systems, it remains the key piece of technology that lies at the heart of your microwave oven today. The cavity magnetron's invention changed the world." Randall also led the King's Col ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Axis Of Rotation
Rotation around a fixed axis is a special case of rotational motion. The fixed-axis hypothesis excludes the possibility of an axis changing its orientation and cannot describe such phenomena as wobbling or precession. According to Euler's rotation theorem, simultaneous rotation along a number of stationary axes at the same time is impossible; if two rotations are forced at the same time, a new axis of rotation will appear. This article assumes that the rotation is also stable, such that no torque is required to keep it going. The kinematics and dynamics of rotation around a fixed axis of a rigid body are mathematically much simpler than those for free rotation of a rigid body; they are entirely analogous to those of linear motion along a single fixed direction, which is not true for ''free rotation of a rigid body''. The expressions for the kinetic energy of the object, and for the forces on the parts of the object, are also simpler for rotation around a fixed axis, than for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coaxial
In geometry, coaxial means that several three-dimensional linear or planar forms share a common axis. The two-dimensional analog is ''concentric''. Common examples: A coaxial cable is a three-dimensional linear structure. It has a wire conductor in the centre (D), a circumferential outer conductor (B), and an insulating medium called the dielectric (C) separating these two conductors. The outer conductor is usually sheathed in a protective PVC outer jacket (A). All these have a common axis. The dimension and material of the conductors and insulation determine the cable's characteristic impedance and attenuation at various frequencies. Coaxial rotors are a three-dimensional planar structure: a pair of helicopter rotors (wings) mounted one above the other on concentric shafts, with the same axis of rotation (but turning in opposite directions). In loudspeaker design, coaxial speakers A coaxial loudspeaker is a loudspeaker system in which the individual driver units radiate s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Secondary Emission
In particle physics, secondary emission is a phenomenon where primary incident particles of sufficient energy, when hitting a surface or passing through some material, induce the emission of secondary particles. The term often refers to the emission of electrons when charged particles like electrons or ions in a vacuum tube strike a metal surface; these are called secondary electrons. In this case, the number of secondary electrons emitted per incident particle is called secondary emission yield. If the secondary particles are ions, the effect is termed ''secondary ion emission''. Secondary electron emission is used in photomultiplier tubes and image intensifier tubes to amplify the small number of photoelectrons produced by photoemission, making the tube more sensitive. It also occurs as an undesirable side effect in electronic vacuum tubes when electrons from the cathode strike the anode, and can cause parasitic oscillation. Applications Secondary emissive materials Co ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thermionic Cathode
In vacuum tubes and gas-filled tubes, a hot cathode or thermionic cathode is a cathode electrode which is heated to make it emit electrons due to thermionic emission. This is in contrast to a cold cathode, which does not have a heating element. The heating element is usually an electrical filament heated by a separate electric current passing through it. Hot cathodes typically achieve much higher power density than cold cathodes, emitting significantly more electrons from the same surface area. Cold cathodes rely on field electron emission or secondary electron emission from positive ion bombardment, and do not require heating. There are two types of hot cathode. In a ''directly heated cathode'', the filament is the cathode and emits the electrons. In an ''indirectly heated cathode'', the filament or ''heater'' heats a separate metal cathode electrode which emits the electrons. From the 1920s to the 1960s, a wide variety of electronic devices used hot-cathode vacuum tubes. T ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dynatron Oscillator
In electronics, the dynatron oscillator, invented in 1918 by Albert Hull at General Electric, is an obsolete vacuum tube electronic oscillator circuit which uses a negative resistance characteristic in early tetrode vacuum tubes, caused by a process called secondary emission. on Peter Millet'Tubebookswebsite It was the first negative resistance vacuum tube oscillator. The dynatron oscillator circuit was used to a limited extent as beat frequency oscillators (BFOs), and local oscillators in vacuum tube radio receivers as well as in scientific and test equipment from the 1920s to the 1940s but became obsolete around World War 2 due to the variability of secondary emission in tubes. Negative transconductance oscillators, such as the transitron oscillator invented by Cleto Brunetti in 1939, are similar negative resistance vacuum tube oscillator circuits which are based on negative transconductance (a fall in current through one grid electrode caused by an increase in voltage on a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
The New York Times
''The New York Times'' (''the Times'', ''NYT'', or the Gray Lady) is a daily newspaper based in New York City with a worldwide readership reported in 2020 to comprise a declining 840,000 paid print subscribers, and a growing 6 million paid digital subscribers. It also is a producer of popular podcasts such as '' The Daily''. Founded in 1851 by Henry Jarvis Raymond and George Jones, it was initially published by Raymond, Jones & Company. The ''Times'' has won 132 Pulitzer Prizes, the most of any newspaper, and has long been regarded as a national " newspaper of record". For print it is ranked 18th in the world by circulation and 3rd in the U.S. The paper is owned by the New York Times Company, which is publicly traded. It has been governed by the Sulzberger family since 1896, through a dual-class share structure after its shares became publicly traded. A. G. Sulzberger, the paper's publisher and the company's chairman, is the fifth generation of the family to head the pa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ballistic Research Laboratory
The Ballistic Research Laboratory (BRL) was a leading U.S. Army research establishment situated at Aberdeen Proving Ground, Maryland that specialized in ballistics ( interior, exterior, and terminal) as well as vulnerability and lethality analysis. BRL served as a major Army center for research and development in technologies related to weapon phenomena, armor, electronic devices, and high-speed computing. In 1992, BRL's mission, personnel, and facilities were incorporated into the newly created Army Research Laboratory (ARL), and BRL was disestablished. BRL is perhaps best known for commissioning the creation of ENIAC, the first electronic general-purpose digital computer. History Formation The history of the Ballistic Research Laboratory dates back to World War I with the Office of the Chief of Ordnance (OCO) within the U.S. Army. During the first year of U.S. involvement in the war, the OCO was responsible for supervising ballistic firings at Sandy Hook Proving Ground in New J ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Advisory Committee
An advisory board is a body that provides non-binding strategic advice to the management of a corporation, organization, or foundation. The informal nature of an advisory board gives greater flexibility in structure and management compared to the board of directors. Unlike the board of directors, the advisory board does not have authority to vote on corporate matters or bear legal fiduciary responsibilities. Many new or small businesses choose to have advisory boards in order to benefit from the knowledge of others, without the expense or formality of the board of directors. Function The function of an advisory board is to offer assistance to enterprises with anything from marketing to managing human resources to influencing the direction of regulators. Advisory boards are composed of accomplished experts offering innovative advice and dynamic perspectives. Meeting quarterly or biannually, boards can provide strategic direction, guide quality improvement, and assess program effe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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