|
Edwin Herbert Hall
Edwin Herbert Hall (November 7, 1855 – November 20, 1938) was an American physicist who discovered the electric field Hall effect. Hall conducted thermoelectric research and also wrote numerous physics textbooks and laboratory manuals. Biography Hall was born in Gorham, Maine, U.S. Hall did his undergraduate work at Bowdoin College, Brunswick, Maine, graduating in 1875. He was the principal of Gould Academy in 1875–1876 and the principal of Brunswick High School in 1876–1877. He did his graduate schooling and research, and earned his Ph.D. degree (1880), at the Johns Hopkins University where his seminal experiments were performed. Discovery of Hall effect The ''Hall effect'' was discovered by Hall in 1879, while working on his doctoral thesis in Physics under the supervision of Henry Augustus Rowland. Hall's experiments in electromagnetics consisted of exposing thin gold leaf (and, later, using various other materials) on a glass plate and tapping off the gold le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gorham, Maine
Gorham is a New England town, town in Cumberland County, Maine, United States. The population was 18,336 at the 2020 United States Census. In addition to its urban village center known as Gorham (CDP), Maine, Gorham Village or simply "the Village," the town encompasses a number of smaller, unincorporated villages and hamlets with distinct historical identities, including South Gorham, West Gorham, Little Falls, Maine, Little Falls, White Rock, and North Gorham. Gorham is home to one of the three campuses of the University of Southern Maine. In 2013, Gorham was voted second-best town in Maine after Hampden by a financial website. Gorham is part of the Portland-South Portland-Biddeford metropolitan area. Initially named Narragansett Number 7, the village was renamed Gorhamtown Plantation in honor of the famous New England United States Army Rangers, Ranger John Gorham I, the great grandfather of John Gorham (military officer), John Gorham 4th. History First called Narragansett Nu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Brunswick High School (Maine)
Brunswick High School is a State school, public Secondary school, high school in Brunswick, Maine, United States. It is a part of the Brunswick School Department. History Although a private school operated under the same name in the 1840s, Brunswick High School was founded as a public school in 1851Wheeler, 473-474 as a part of a school consolidation and restructuring effort. In its over 150-year history, the school has occupied three sites within Brunswick. The first high school was located within a larger school building at the corner of Federal and Green Streets (now 46 Federal Street). Hawthorne Elementary School was subsequently located at 46 Federal Street until its closure in 2010. Its most recent use is as the central office for the Brunswick School Department. In 1938, a new high school building was planned by architect Harry S. Coombs and constructed with Works Progress Administration funds on the corner of Spring and McKeen Streets to the west of downtown Brunswick. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Temperature
Temperature is a physical quantity that quantitatively expresses the attribute of hotness or coldness. Temperature is measurement, measured with a thermometer. It reflects the average kinetic energy of the vibrating and colliding atoms making up a substance. Thermometers are calibrated in various temperature scales that historically have relied on various reference points and thermometric substances for definition. The most common scales are the Celsius scale with the unit symbol °C (formerly called ''centigrade''), the Fahrenheit scale (°F), and the Kelvin scale (K), with the third being used predominantly for scientific purposes. The kelvin is one of the seven base units in the International System of Units (SI). Absolute zero, i.e., zero kelvin or −273.15 °C, is the lowest point in the thermodynamic temperature scale. Experimentally, it can be approached very closely but not actually reached, as recognized in the third law of thermodynamics. It would be impossible ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
IEEE
The Institute of Electrical and Electronics Engineers (IEEE) is an American 501(c)(3) organization, 501(c)(3) public charity professional organization for electrical engineering, electronics engineering, and other related disciplines. The IEEE has a corporate office in New York City and an operations center in Piscataway, New Jersey. The IEEE was formed in 1963 as an amalgamation of the American Institute of Electrical Engineers and the Institute of Radio Engineers. History The IEEE traces its founding to 1884 and the American Institute of Electrical Engineers. In 1912, the rival Institute of Radio Engineers was formed. Although the AIEE was initially larger, the IRE attracted more students and was larger by the mid-1950s. The AIEE and IRE merged in 1963. The IEEE is headquartered in New York City, but most business is done at the IEEE Operations Center in Piscataway, New Jersey, opened in 1975. The Australian Section of the IEEE existed between 1972 and 1985, after which it s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hall-effect Thruster
In spacecraft propulsion, a Hall-effect thruster (HET) is a type of ion thruster in which the propellant is accelerated by an electric field. Hall-effect thrusters (based on the discovery by Edwin Hall) are sometimes referred to as Hall thrusters or Hall-current thrusters. Hall effect, Hall-effect thrusters use a magnetic field to limit the electrons' axial motion and then use them to ionize propellant, efficiently accelerate the ions to produce thrust, and neutralize the ions in the plume. The Hall-effect thruster is classed as a moderate specific impulse (1,600s) space propulsion technology and has benefited from considerable theoretical and experimental research since the 1960s. Hall thrusters operate on a variety of propellants, the most common being xenon and krypton. Other propellants of interest include argon, bismuth, iodine, magnesium, zinc and adamantane. Hall thrusters are able to accelerate their exhaust to effective exhaust velocity, speeds between 10 and 80 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hall Effect Sensor
A Hall effect sensor (also known as a Hall sensor or Hall probe) is any sensor incorporating one or more Hall elements, each of which produces a voltage proportional to one axial component of the Magnetic field#The B-field, magnetic field vector using the Hall effect (named for physicist Edwin Hall). Hall sensors are used for proximity sensing, positioning (navigation), positioning, Speed limit enforcement, speed detection, and current sensing applications and are common in industrial and consumer applications. Hundreds of millions of Hall sensor integrated circuits (ICs) are sold each year by about 50 manufacturers, with the global market around a billion United States dollar, dollars. Principles In a Hall sensor, a fixed DC current, DC bias current is applied along one axis across a thin strip of metal called the Hall element transducer. Sensing electrodes on opposite sides of the Hall element along ''another'' axis measure the difference in electric potential (voltage) ac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philosophical Magazine
The ''Philosophical Magazine'' is one of the oldest scientific journals published in English. It was established by Alexander Tilloch in 1798;John Burnett"Tilloch, Alexander (1759–1825)" Dictionary of National Biography#Oxford Dictionary of National Biography, Oxford Dictionary of National Biography, Oxford University Press, Sept 2004; online edn, May 2006, accessed 17 Feb 2010 in 1822 Richard Taylor (editor), Richard Taylor became joint editor and it has been published continuously by Taylor & Francis ever since. Early history The name of the journal dates from a period when "natural philosophy" embraced all aspects of science. The very first paper published in the journal carried the title "Account of Mr Cartwright's Patent Steam Engine". Other articles in the first volume include "Methods of discovering whether Wine has been adulterated with any Metals prejudicial to Health" and "Description of the Apparatus used by Lavoisier to produce Water from its component Parts, Oxyg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
American Journal Of Science
The ''American Journal of Science'' (''AJS'') is the United States of America's longest-running scientific journal, having been published continuously since its conception in 1818 by Professor Benjamin Silliman, who edited and financed it himself. It was initially called the ''American Journal of Science and Arts'' until a name change in 1880, but its focus was always on natural sciences and especially on geology and related subjects. In early years, the journal was often referred to as "Silliman's Journal", and the publication became associated with Yale University due to his long tenure there (1804–1853). The editorship long remained in the family of Professor Silliman, as he was assisted by his son, Benjamin Silliman Jr., from 1838. On the death of the elder Silliman in 1864, he was succeeded as chief editor by his son-in-law, James Dwight Dana, and then from 1895 till 1926 by Dana's son Edward Salisbury Dana. Associate editors included the botanist Asa Gray and the zoologi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Field
A magnetic field (sometimes called B-field) is a physical field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field. A permanent magnet's magnetic field pulls on ferromagnetic materials such as iron, and attracts or repels other magnets. In addition, a nonuniform magnetic field exerts minuscule forces on "nonmagnetic" materials by three other magnetic effects: paramagnetism, diamagnetism, and antiferromagnetism, although these forces are usually so small they can only be detected by laboratory equipment. Magnetic fields surround magnetized materials, electric currents, and electric fields varying in time. Since both strength and direction of a magnetic field may vary with location, it is described mathematically by a function (mathematics), function assigning a Euclidean vector, vector to each point of space, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Current (electricity)
An electric current is a flow of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is defined as the net rate of flow of electric charge through a surface. The moving particles are called charge carriers, which may be one of several types of particles, depending on the conductor. In electric circuits the charge carriers are often electrons moving through a wire. In semiconductors they can be electrons or holes. In an electrolyte the charge carriers are ions, while in plasma, an ionized gas, they are ions and electrons. In the International System of Units (SI), electric current is expressed in units of ampere (sometimes called an "amp", symbol A), which is equivalent to one coulomb per second. The ampere is an SI base unit and electric current is a base quantity in the International System of Quantities (ISQ). Electric current is also known as amperage and is measured using a device called an ''ammeter''. Electric currents ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potential Difference
Voltage, also known as (electrical) potential difference, electric pressure, or electric tension, is the difference in electric potential between two points. In a static electric field, it corresponds to the work needed per unit of charge to move a positive test charge from the first point to the second point. In the International System of Units (SI), the derived unit for voltage is the ''volt'' (''V''). The voltage between points can be caused by the build-up of electric charge (e.g., a capacitor), and from an electromotive force (e.g., electromagnetic induction in a generator). On a macroscopic scale, a potential difference can be caused by electrochemical processes (e.g., cells and batteries), the pressure-induced piezoelectric effect, and the thermoelectric effect. Since it is the difference in electric potential, it is a physical scalar quantity. A voltmeter can be used to measure the voltage between two points in a system. Often a common reference potential su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Glass
Glass is an amorphous (non-crystalline solid, non-crystalline) solid. Because it is often transparency and translucency, transparent and chemically inert, glass has found widespread practical, technological, and decorative use in window panes, tableware, and optics. Some common objects made of glass are named after the material, e.g., a Tumbler (glass), "glass" for drinking, "glasses" for vision correction, and a "magnifying glass". Glass is most often formed by rapid cooling (quenching) of the Melting, molten form. Some glasses such as volcanic glass are naturally occurring, and obsidian has been used to make arrowheads and knives since the Stone Age. Archaeological evidence suggests glassmaking dates back to at least 3600 BC in Mesopotamia, Ancient Egypt, Egypt, or Syria. The earliest known glass objects were beads, perhaps created accidentally during metalworking or the production of faience, which is a form of pottery using lead glazes. Due to its ease of formability int ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
