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Reverberation

Reverberation (commonly shortened to reverb), in acoustics, is a persistence of sound after it is produced. Reverberation is created when a sound or signal is reflected. This causes numerous reflections to build up and then decay as the sound is absorbed by the surfaces of objects in the space – which could include furniture, people, and air. This is most noticeable when the sound source stops but the reflections continue, their amplitude decreasing, until zero is reached.

Reverberation is frequency dependent: the length of the decay, or reverberation time, receives special consideration in the architectural design of spaces which need to have specific reverberation times to achieve optimum performance for their intended activity. In comparison to a distinct echo, that is detectable at a minimum of 50 to 100 ms after the previous sound, reverberation is the occurrence of reflections that arrive in a sequence of less than approximately 50 ms. As time passes, the amplitude of the reflections gradually reduces to non-noticeable levels. Reverberation is not limited to indoor spaces as it exists in forests and other outdoor environments where reflection exists.

Reverberation occurs naturally when a person sings, talks, or plays an instrument acoustically in a hall or performance space with sound-reflective surfaces. Reverberation is applied artificially by using reverb effects, which simulate reverb through means including echo chambers, vibrations sent through metal, and digital processing.

Although reverberation can add naturalness to recorded sound by adding a sense of space, it can also reduce speech intelligibility, especially when noise is also present. People with hearing loss, including users of hearing aids, frequently report difficulty in understanding speech in reverberant, noisy situations. Reverberation is also a significant source of mistakes in automatic speech recognition.

Dereverberation is the process of reducing the level of reverberation in a sound or signal.

Reverberation time is a measure of the time required for the sound to "fade away" in an enclosed area after the source of the sound has stopped.

When it comes to accurately measuring reverberation time with a meter, the term T60 (an abbreviation for reverberation time 60 dB) is used. T60 provides an objective reverberation time measurement. It is defined as the time it takes for the sound pressure level to reduce by 60 dB, measured after the generated test signal is abruptly ended.

Reverberation time is frequently stated as a single value if measured as a wideband signal (20 Hz to 20 kHz). However, being frequency-dependent, it can be more precisely described in terms of frequency bands (one octave, 1/3 octave, 1/6 octave, etc.). Being frequency dependent, the reverberation time measured in narrow bands will differ depending on the frequency band being measured. For precision, it is important to know what ranges of frequencies are being described by a reverberation time measurement.

In the late 19th century, Wallace Clement Sabine started experiments at Harvard University to investigate the impact of absorption on the reverberation time. Using a portable wind chest and organ pipes as a sound source, a stopwatch and his ears, he measured the time from interruption of the source to inaudibility (a difference of roughly 60 dB). He found that the reverberation time is proportional to room dimensions and inversely proportional to the amount of absorption present.

The optimum reverberation time for a space in which music is played depends on the type of music that is to be played in the space. Rooms used for speech typically need a shorter reverberation time so that speech can be understood more clearly. If the reflected sound from one syllable is still heard when the next syllable is spoken, it may be difficult to understand what was said. "Cat", "cab", and "cap" may all sound very similar. If on the other hand the reverberation time is too short, tonal balance and loudness may suffer. Reverberation effects are often used in studios to add depth to sounds. Reverberation changes the perceived spectral structure of a sound but does not alter the pitch.

Basic factors that affect a room's reverberation time include the size and shape of the enclosure as well as the materials used in the construction of the room. Every object placed within the enclosure can also affect this reverberation time, including people and their belongings.

Measurement
Historically, reverberation time could only be measured using a level recorder (a plotting device which graphs the noise level against time on a ribbon of moving paper). A loud noise is produced, and as the sound dies away the trace on the level recorder will show a distinct slope. Analysis of this slope reveals the measured reverberation time. Some modern digital sound level meters can carry out this analysis automatically.

Several methods exist for measuring reverberation time. An impulse can be measured by creating a sufficiently loud noise (which must have a defined cut-off point). Impulse noise sources such as a blank pistol shot or balloon burst may be used to measure the impulse response of a room.

Alternatively, a random noise signal such as pink noise or white noise may be generated through a loudspeaker, and then turned off. This is known as the interrupted method, and the measured result is known as the interrupted response.

A two-port measurement system can also be used to measure noise introduced into a space and compare it to what is subsequently measured in the space. Consider sound reproduced by a loudspeaker into a room. A recording of the sound in the room can be made and compared to what was sent to the loudspeaker. The two signals can be compared mathematically. This two port measurement system utilizes a Fourier transform to mathematically derive the impulse response of the room. From the impulse response, the reverberation time can be calculated. Using a two-port system allows reverberation time to be measured with signals other than loud impulses. Music or recordings of other sounds can be used. This allows measurements to be taken in a room after the audience is present.

Under some restrictions, even simple sound sources like handclaps can be used for measurement of reverberation

Reverberation time is usually stated as a decay time and is measured in seconds. There may or may not be any statement of the frequency band used in the measurement. Decay time is the time it takes the signal to diminish 60 dB below the original sound. It is often difficult to inject enough sound into the room to measure a decay of 60 dB, particularly at lower frequencies. If the decay is linear, it is sufficient to measure a drop of 20 dB and multiply the time by 3, or a drop of 30 dB and multiply the time by 2. These are the so-called T20 and T30 measurement methods.

The RT60 reverberation time measurement is defined in the ISO 3382-1 standard for performance spaces, the ISO 3382-2 standard for ordinary rooms, and the ISO 3382-3 for open-plan offices, as well as the ASTM E2235 standard.

The concept of reverberation time implicitly supposes that the decay rate of the sound is exponential, so that the sound level diminishes regularly, at a rate of so many dB per second. It is not often the case in real rooms, depending on the disposition of reflective, dispersive and absorbing surfaces. Moreover, successive measurement of the sound level often yields very different results, as differences in phase in the exciting sound build up in notably different sound waves. In 1965, Manfred R. Schroeder published "A new method of Measuring Reverberation Time" in the Journal of the Acoustical Society of America. He proposed to measure, not the power of the sound, but the energy, by integrating it. This made it possible to show the variation in the rate of decay and to free acousticians from the necessity of averaging many measurements.

Sabine equation
Sabine's reverberation equation was developed in the late 1890s in an empirical fashion. He established a relationship between the T60 of a room, its volume, and its total absorption (in sabins). This is given by the equation:

 * $$T_{60} = \frac{24 \ln 10^1}{c_{20}} \frac{V}{Sa} \approx 0.1611\,\mathrm{s}\mathrm{m}^{-1} \frac{V}{Sa}$$.

where c20 is the speed of sound in the room (at 20 °C), V is the volume of the room in m3, S total surface area of room in m2, a is the average absorption coefficient of room surfaces, and the product Sa is the total absorption in sabins.

The total absorption in sabins (and hence reverberation time) generally changes depending on frequency (which is defined by the acoustic properties of the space). The equation does not take into account room shape or losses from the sound traveling through the air (important in larger spaces). Most rooms absorb less sound energy in the lower frequency ranges resulting in longer reverb times at lower frequencies.

Sabine concluded that the reverberation time depends upon the reflectivity of sound from various surfaces available inside the hall. If the reflection is coherent, the reverberation time of the hall will be longer; the sound will take more time to die out.

The reverberation time RT60 and the volume V of the room have great influence on the critical distance dc (conditional equation):

d_\mathrm{c} \approx 0{.}057 \cdot \sqrt \frac{V}{RT_{60}} $$

where critical distance $$d_c$$ is measured in meters, volume $$V$$ is measured in m³, and reverberation time RT60 is measured in seconds.

Eyring equation
Eyring's reverberation time equation was proposed by Carl F. Eyring of Bell Labs in 1930. This equation aims to better estimate the reverberation time in small rooms with relatively large quantities of sound absorption, identified by Eyring as "dead" rooms. These rooms tend to have lower reverberation times than larger, more acoustically live rooms. Eyring's equation is similar in form to Sabine's equation, but includes modifications to logarithmically scale the absorption term. The units and variables within the equation are the same as those defined for Sabine's equation. The Eyring reverberation time is given by the equation:

 * $$T_{60} \approx -0.161\ \frac{V}{S \ln (1-a)}$$.

Eyring's equation was developed from first principles using an image source model of sound reflection, as opposed to Sabine's empirical approach. The experimental results obtained by Sabine generally agree with Eyring's equation since the two formulae become identical for very live rooms, the type in which Sabine worked. However, Eyring's equation becomes more valid for smaller rooms with large quantities of absorption. As a result, the Eyring equation is often implemented to estimate the reverberation time in recording studio control rooms or other critical listening environments with high quantities of sound absorption. The Sabine equation tends to over-predict reverberation time for small rooms with high amounts of absorption. For this reason, reverberation time calculators available for smaller recording studio environments, such as home recording studios, often utilize Eyring's equation.

Absorption coefficient
The absorption coefficient of a material is a number between 0 and 1 which indicates the proportion of sound which is absorbed by the surface compared to the proportion which is reflected back to the room. A large, fully open window would offer no reflection as any sound reaching it would pass straight out and no sound would be reflected. This would have an absorption coefficient of 1. Conversely, a thick, smooth painted concrete ceiling would be the acoustic equivalent of a mirror and have an absorption coefficient very close to 0.

In music
The Atlantic described reverberation as "arguably the oldest and most universal sound effect in music", used in music as early as 10th-century plainsong. Composers including Bach wrote music to exploit the acoustics of certain buildings. Gregorian chant may have developed in response to the long reverberation time of cathedrals, limiting the number of notes that could be sung before blending chaotically.

Artificial reverberation is applied to sound using reverb effects. These simulate reverb through means including echo chambers, vibrations sent through metal, and digital processing.

title: Reverberation


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Virtual particle

A virtual particle is a theoretical transient particle that exhibits some of the characteristics of an ordinary particle, while having its existence limited by the uncertainty principle, which allows the virtual particles to spontaneously emerge from vacuum at short time and space ranges. The concept of virtual particles arises in the perturbation theory of quantum field theory (QFT) where interactions between ordinary particles are described in terms of exchanges of virtual particles. A process involving virtual particles can be described by a schematic representation known as a Feynman diagram, in which virtual particles are represented by internal lines.

Virtual particles do not necessarily carry the same mass as the corresponding ordinary particle, although they always conserve energy and momentum. The closer its characteristics come to those of ordinary particles, the longer the virtual particle exists. They are important in the physics of many processes, including particle scattering and Casimir forces. In quantum field theory, forces—such as the electromagnetic repulsion or attraction between two charges—can be thought of as resulting from the exchange of virtual photons between the charges. Virtual photons are the exchange particles for the electromagnetic interaction.

The term is somewhat loose and vaguely defined, in that it refers to the view that the world is made up of "real particles". "Real particles" are better understood to be excitations of the underlying quantum fields. Virtual particles are also excitations of the underlying fields, but are "temporary" in the sense that they appear in calculations of interactions, but never as asymptotic states or indices to the scattering matrix. The accuracy and use of virtual particles in calculations is firmly established, but as they cannot be detected in experiments, deciding how to precisely describe them is a topic of debate. Although widely used, they are by no means a necessary feature of QFT, but rather are mathematical conveniences - as demonstrated by lattice field theory, which avoids using the concept altogether.

Properties
The concept of virtual particles arises in the perturbation theory of quantum field theory, an approximation scheme in which interactions (in essence, forces) between actual particles are calculated in terms of exchanges of virtual particles. Such calculations are often performed using schematic representations known as Feynman diagrams, in which virtual particles appear as internal lines. By expressing the interaction in terms of the exchange of a virtual particle with four-momentum $q$, where $q$ is given by the difference between the four-momenta of the particles entering and leaving the interaction vertex, both momentum and energy are conserved at the interaction vertices of the Feynman diagram.

A virtual particle does not precisely obey the energy–momentum relation $m^{2}c^{4} = E^{2} − p^{2}c^{2}$. Its kinetic energy may not have the usual relationship to velocity. It can be negative. This is expressed by the phrase off mass shell. The probability amplitude for a virtual particle to exist tends to be canceled out by destructive interference over longer distances and times. As a consequence, a real photon is massless and thus has only two polarization states, whereas a virtual one, being effectively massive, has three polarization states.

Quantum tunnelling may be considered a manifestation of virtual particle exchanges. The range of forces carried by virtual particles is limited by the uncertainty principle, which regards energy and time as conjugate variables; thus, virtual particles of larger mass have more limited range.

Written in the usual mathematical notations, in the equations of physics, there is no mark of the distinction between virtual and actual particles. The amplitudes of processes with a virtual particle interfere with the amplitudes of processes without it, whereas for an actual particle the cases of existence and non-existence cease to be coherent with each other and do not interfere any more. In the quantum field theory view, actual particles are viewed as being detectable excitations of underlying quantum fields. Virtual particles are also viewed as excitations of the underlying fields, but appear only as forces, not as detectable particles. They are "temporary" in the sense that they appear in some calculations, but are not detected as single particles. Thus, in mathematical terms, they never appear as indices to the scattering matrix, which is to say, they never appear as the observable inputs and outputs of the physical process being modelled.

There are two principal ways in which the notion of virtual particles appears in modern physics. They appear as intermediate terms in Feynman diagrams; that is, as terms in a perturbative calculation. They also appear as an infinite set of states to be summed or integrated over in the calculation of a semi-non-perturbative effect. In the latter case, it is sometimes said that virtual particles contribute to a mechanism that mediates the effect, or that the effect occurs through the virtual particles.

Manifestations
There are many observable physical phenomena that arise in interactions involving virtual particles. For bosonic particles that exhibit rest mass when they are free and actual, virtual interactions are characterized by the relatively short range of the force interaction produced by particle exchange. Confinement can lead to a short range, too. Examples of such short-range interactions are the strong and weak forces, and their associated field bosons.

For the gravitational and electromagnetic forces, the zero rest-mass of the associated boson particle permits long-range forces to be mediated by virtual particles. However, in the case of photons, power and information transfer by virtual particles is a relatively short-range phenomenon (existing only within a few wavelengths of the field-disturbance, which carries information or transferred power), as for example seen in the characteristically short range of inductive and capacitative effects in the near field zone of coils and antennas.

Some field interactions which may be seen in terms of virtual particles are:
 * The Coulomb force (static electric force) between electric charges. It is caused by the exchange of virtual photons. In symmetric 3-dimensional space this exchange results in the inverse square law for electric force. Since the photon has no mass, the coulomb potential has an infinite range.
 * The magnetic field between magnetic dipoles. It is caused by the exchange of virtual photons. In symmetric 3-dimensional space, this exchange results in the inverse cube law for magnetic force. Since the photon has no mass, the magnetic potential has an infinite range. Even though the range is infinite, the time lapse allowed for a virtual photon existence is not infinite.
 * Electromagnetic induction. This phenomenon transfers energy to and from a magnetic coil via a changing (electro)magnetic field.
 * The strong nuclear force between quarks is the result of interaction of virtual gluons. The residual of this force outside of quark triplets (neutron and proton) holds neutrons and protons together in nuclei, and is due to virtual mesons such as the pi meson and rho meson.
 * The weak nuclear force is the result of exchange by virtual W and Z bosons.
 * The spontaneous emission of a photon during the decay of an excited atom or excited nucleus; such a decay is prohibited by ordinary quantum mechanics and requires the quantization of the electromagnetic field for its explanation.
 * The Casimir effect, where the ground state of the quantized electromagnetic field causes attraction between a pair of electrically neutral metal plates.
 * The van der Waals force, which is partly due to the Casimir effect between two atoms.
 * Vacuum polarization, which involves pair production or the decay of the vacuum, which is the spontaneous production of particle-antiparticle pairs (such as electron-positron).
 * Lamb shift of positions of atomic levels.
 * The impedance of free space, which defines the ratio between the electric field strength $|E|$ and the magnetic field strength $|H|$: $Z0 = |E| / |H|$.
 * Much of the so-called near-field of radio antennas, where the magnetic and electric effects of the changing current in the antenna wire and the charge effects of the wire's capacitive charge may be (and usually are) important contributors to the total EM field close to the source, but both of which effects are dipole effects that decay with increasing distance from the antenna much more quickly than do the influence of "conventional" electromagnetic waves that are "far" from the source. These far-field waves, for which $E$ is (in the limit of long distance) equal to $cB$, are composed of actual photons. Actual and virtual photons are mixed near an antenna, with the virtual photons responsible only for the "extra" magnetic-inductive and transient electric-dipole effects, which cause any imbalance between $E$ and $cB$. As distance from the antenna grows, the near-field effects (as dipole fields) die out more quickly, and only the "radiative" effects that are due to actual photons remain as important effects. Although virtual effects extend to infinity, they drop off in field strength as $1/r2$ rather than the field of EM waves composed of actual photons, which drop as $1/r$.

Most of these have analogous effects in solid-state physics; indeed, one can often gain a better intuitive understanding by examining these cases. In semiconductors, the roles of electrons, positrons and photons in field theory are replaced by electrons in the conduction band, holes in the valence band, and phonons or vibrations of the crystal lattice. A virtual particle is in a virtual state where the probability amplitude is not conserved. Examples of macroscopic virtual phonons, photons, and electrons in the case of the tunneling process were presented by Günter Nimtz and Alfons A. Stahlhofen.

Feynman diagrams
The calculation of scattering amplitudes in theoretical particle physics requires the use of some rather large and complicated integrals over a large number of variables. These integrals do, however, have a regular structure, and may be represented as Feynman diagrams. The appeal of the Feynman diagrams is strong, as it allows for a simple visual presentation of what would otherwise be a rather arcane and abstract formula. In particular, part of the appeal is that the outgoing legs of a Feynman diagram can be associated with actual, on-shell particles. Thus, it is natural to associate the other lines in the diagram with particles as well, called the "virtual particles". In mathematical terms, they correspond to the propagators appearing in the diagram.

In the adjacent image, the solid lines correspond to actual particles (of momentum p1 and so on), while the dotted line corresponds to a virtual particle carrying momentum k. For example, if the solid lines were to correspond to electrons interacting by means of the electromagnetic interaction, the dotted line would correspond to the exchange of a virtual photon. In the case of interacting nucleons, the dotted line would be a virtual pion. In the case of quarks interacting by means of the strong force, the dotted line would be a virtual gluon, and so on.

Virtual particles may be mesons or vector bosons, as in the example above; they may also be fermions. However, in order to preserve quantum numbers, most simple diagrams involving fermion exchange are prohibited. The image to the right shows an allowed diagram, a one-loop diagram. The solid lines correspond to a fermion propagator, the wavy lines to bosons.

Vacuums
In formal terms, a particle is considered to be an eigenstate of the particle number operator a†a, where a is the particle annihilation operator and a† the particle creation operator (sometimes collectively called ladder operators). In many cases, the particle number operator does not commute with the Hamiltonian for the system. This implies the number of particles in an area of space is not a well-defined quantity but, like other quantum observables, is represented by a probability distribution. Since these particles are not certain to exist, they are called virtual particles or vacuum fluctuations of vacuum energy. In a certain sense, they can be understood to be a manifestation of the time-energy uncertainty principle in a vacuum.

An important example of the "presence" of virtual particles in a vacuum is the Casimir effect. Here, the explanation of the effect requires that the total energy of all of the virtual particles in a vacuum can be added together. Thus, although the virtual particles themselves are not directly observable in the laboratory, they do leave an observable effect: Their zero-point energy results in forces acting on suitably arranged metal plates or dielectrics. On the other hand, the Casimir effect can be interpreted as the relativistic van der Waals force.

Pair production
Virtual particles are often popularly described as coming in pairs, a particle and antiparticle which can be of any kind. These pairs exist for an extremely short time, and then mutually annihilate, or in some cases, the pair may be boosted apart using external energy so that they avoid annihilation and become actual particles, as described below.

This may occur in one of two ways. In an accelerating frame of reference, the virtual particles may appear to be actual to the accelerating observer; this is known as the Unruh effect. In short, the vacuum of a stationary frame appears, to the accelerated observer, to be a warm gas of actual particles in thermodynamic equilibrium.

Another example is pair production in very strong electric fields, sometimes called vacuum decay. If, for example, a pair of atomic nuclei are merged to very briefly form a nucleus with a charge greater than about 140, (that is, larger than about the inverse of the fine-structure constant, which is a dimensionless quantity), the strength of the electric field will be such that it will be energetically favorable to create positron–electron pairs out of the vacuum or Dirac sea, with the electron attracted to the nucleus to annihilate the positive charge. This pair-creation amplitude was first calculated by Julian Schwinger in 1951.

Compared to actual particles
As a consequence of quantum mechanical uncertainty, any object or process that exists for a limited time or in a limited volume cannot have a precisely defined energy or momentum. For this reason, virtual particles – which exist only temporarily as they are exchanged between ordinary particles – do not typically obey the mass-shell relation; the longer a virtual particle exists, the more the energy and momentum approach the mass-shell relation.

The lifetime of real particles is typically vastly longer than the lifetime of the virtual particles. Electromagnetic radiation consists of real photons which may travel light years between the emitter and absorber, but (Coulombic) electrostatic attraction and repulsion is a relatively short-range force that is a consequence of the exchange of virtual photons.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Virtual particle


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USS Washington

USS Washington may refer to:

Ships named in honor of George Washington:

 * USS Washington (1775) was a schooner acquired in October 1775 and captured by the Royal Navy in December the same year
 * USS Washington (1776 row galley) was a row galley acquired in January 1776 with an unknown fate after August the same year
 * USS Washington (1776 frigate) was one of 13 frigates authorized by the Continental Congress, launched in August 1776; and scuttled in November 1777 to prevent capture
 * USS Washington (1776 lateen-rigged galley) was a galley built and subsequently captured by the Royal Navy in October 1776
 * USS Washington (1814) was a ship of the line on active service from 1815 to 1820
 * USRC Washington (1833) was a revenue cutter launched in 1833 and sold in June 1837

Ships or boats named in honor of the State of Washington

 * USS Washington (ACR-11) was a Tennessee-class cruiser armored cruiser, launched in 1905, renamed Seattle in 1916, reclassified as a heavy cruiser in 1920; and scrapped 1946
 * USS Washington (BB-47) was a Colorado-class battleship launched in 1921 and sunk as a gunnery target in 1924 after her construction was halted in 1922
 * USS Washington (BB-56) was a North Carolina-class battleship launched in 1940, decommissioned in 1947, and scrapped in 1961
 * USS Washington (SSN-787) is a Virginia-class submarine

Others
 * USRC Washington, was a revenue cutter named after Peter G. Washington, Assistant Secretary of the Treasury. The ship was launched in 1837 and seized by Confederate Navy in June 1861.
 * Washington, was a United States Navy seagoing coal barge during 1917

title: USS Washington


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USS West Virginia

Three ships of the United States Navy have been named USS West Virginia in honor of the 35th state.

 * USS West Virginia (ACR-5) was a Pennsylvania-class cruiser.
 * USS West Virginia (BB-48) was a Colorado-class battleship.
 * USS West Virginia (SSBN-736) is an Ohio-class submarine.

title: USS West Virginia


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USS Wisconsin

USS Wisconsin may refer to:

 * USS Wisconsin (BB-9) was an Illinois-class battleship
 * USS Wisconsin (BB-64) is an Iowa-class battleship
 * USS Wisconsin (SSBN-827) a planned Columbia-class submarine

title: USS Wisconsin


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USS Wyoming

One ship of the United States Navy has been named USS Wyoming in honor of the Wyoming Valley in eastern Pennsylvania that runs along the Susquehanna River. Three others have been named in honor of the state of Wyoming.

 * USS Wyoming (1859) was a screw sloop that operated on the California coast during the American Civil War and fought the forces of a Japanese warlord in the Battle of Shimonoseki.
 * USS Wyoming (BM-10), an Arkansas-class monitor monitor, later renamed USS Cheyenne.
 * USS Wyoming (BB-32) was the lead ship of her class of battleships.
 * USS Wyoming (SSBN-742) is an Ohio-class ballistic missile submarine.

title: USS Wyoming


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Secondo Campini

Secondo Campini (August 28, 1904 – February 7, 1980) was an Italian engineer and one of the pioneers of the jet engine.

Campini was born at Bologna, Emilia-Romagna. In 1931 he wrote a proposal for the Italian Air Ministry on the value of jet propulsion, and in 1932 demonstrated a jet-powered boat in Venice. With support of the Air Ministry, he began work with Italian aircraft manufacturer Caproni to develop a jet aircraft, the Caproni Campini C.C.2, which first flew in 1940.

The "motorjet" that Campini developed to propel the C.C.2 is substantially different from the jet engines of today. Campini's engine used a conventional piston engine to compress air, which was then mixed with fuel and ignited. Modern jets are based on the turbojet principle, but Campini's engine was nevertheless a true jet, since it was the reactive force of the burning exhaust gases that pushed the aircraft along.

After World War II, Campini emigrated to the US at the request of Preston Tucker (noted for the Tucker 48 automobile), who wanted Campini to help him with his new corporation. Tucker asked Campini to both help him develop a turbine powered car, and also used his fame to attempt to secure a US Air Force development contract for the Tucker Corporation. After the Tucker Corporation folded in 1948, he worked on a number of military projects, including the YB-49 flying-wing bomber.

Campini died in Milan in 1980.

title: Secondo Campini


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USS Wyoming (BM-10)

USS Wyoming was the second ship of the United States Navy to bear that name, but the first to bear it in honor of the 44th state. The first Wyoming was named for Wyoming Valley in eastern Pennsylvania.

Wyoming was ordered on 4 May 1898, and awarded to the Union Iron Works, San Francisco, 5 October 1898. The keel of Monitor No. 10 was laid down on 11 April 1898. She was launched on 8 September 1900 sponsored by Miss Hattie Warren, daughter of Senator Francis E. Warren of Wyoming, and commissioned at the Mare Island Naval Shipyard, Vallejo, California, on 8 December 1902. The total cost for the hull, machinery, armor and armament was $1,624,270.59.

In 1909, the ship was renamed Cheyenne to free her original name for a new battleship and she was allocated the hull number M-10, which was altered to BM-10 in 1920 and ultimately IX-4 in 1921. She was ultimately sold for scrap in 1939.

Design
The Arkansas-class monitors had been designed to combine a heavy striking power with easy concealment and negligible target area. They had a displacement of 3225 LT, measured 255 ft in overall length, with a beam of 50 ft and a draft of 12 ft. She was manned by a total crew of 13 officers and 209 men.

Wyoming, the first ship in the fleet to be converted to oil power, was powered by two vertical triple expansion engines driving two screw propellers with steam generated by four Babcock & Wilcox boilers. The engines in Wyoming were designed to produce 2400 ihp with a top speed of 12.5 kn, however, on sea trials she was only able to produce 2336 ihp with a top speed of 12.4 kn. Wyoming was designed to provide a range of 2360 nmi at 10 kn.

The ship was armed with a main battery of two 12 in/40 caliber guns, either Mark 3 or Mark 4, in a Mark 4 turret. The secondary battery consisted of four 4 in/50 caliber Mark 7 guns along with three 6-pounder 57 mm guns. The main belt armor was 11 in in the middle tapering to 5 in at the ends. The gun turrets were between 10 and 9 in, with 11 to 9 in barbettes. Wyoming also had a 1.5 in deck.

Wyoming
After fitting out at Mare Island, Wyoming ran her trials and exercises in San Pablo Bay and San Francisco Bay and conducted exercises and target practice off the southern California coast through the summer of 1903 before she headed south in the autumn, reaching Acapulco, Mexico, on 31 October. She subsequently shifted further south, to Colombia, where a civil war and a rebellion in the Panamanian territory instigated by the United States government, took part in the independence of the Panamanian territory from Colombia, to later build the Panama Canal. The monitor accordingly arrived in Panamanian waters on 13 November and sailed up the Tuira River in company with the protected cruiser USS Boston (1884), with a company of Marines under Lieutenant S.A.M. Patterson, USMC, and Lieutenant C.B. Taylor, USMC, embarked, to land at Yariza and observe the movements of Colombian troops.

The presence of American armed might there and elsewhere ultimately aided in independence for the Panamanians. During that time, Wyoming anchored at the Bay of San Miguel, Panama, on 15 December. The following day, a boat with 11 Marines embarked for the port of La Palma, Panama, under sail. While Boston departed the scene on 17 December, Wyoming shifted to La Palma on the following day. There, Lieutenant Patterson, USMC, with a detachment of 25 marines, commandeered the steamer Tuira and took her upriver. While the Marines were gone, a party of evacuated American nationals came out to the monitor in her gig. Meanwhile, Patterson's Marines had joined the ship's landing force at the village of Real to keep an eye on American interests there. Back at La Palma, Wyoming continued to take on board American nationals fleeing from the troubled land and kept up a steady stream of supplies to her landing party of bluejackets and Marines at Real. Ultimately, when the need for them had passed, the landing party returned to the ship on Christmas Eve. Wyoming remained in Panamanian waters into the spring of 1904 keeping a figurative eye on local conditions before she departed Panama Bay on 19 April, bound for Acapulco, Mexico. After remaining at that port from 27 to 29 April, Wyoming visited Pichilinque, Mexico from 3 to 9 May. She subsequently reached San Diego, on 14 May for a nine-day stay.

For the remainder of 1904, Wyoming operated off the West Coast, ranging from Brighton Beach, California, and Ventura, California, to Bellingham, Washington, and Portland, Oregon. She attended a regatta at Astoria, Oregon, from 22 to 27 August and later took part in ceremonies at the "unveiling of monuments" at Griffin Bay, San Juan Islands and Roche Harbor before she entered the Puget Sound Navy Yard, Bremerton, Washington, on 22 October. Wyoming was overhauled there into the following year. She departed the Pacific Northwest on 26 January 1905 and steamed via San Francisco to Magdalena Bay, Mexico, for target practice. Later cruising to Acapulco and Panamanian waters, Wyoming also operated off San Salvador and Port Harford, California, before she returned to Mare Island on 30 July to be decommissioned on 29 August 1905.

Recommissioned on 8 October 1908 with Commander John J. Knapp in command, Wyoming spent over two months at Mare Island refitting. Converted to fuel oil – the first ship to do so in the United States Navy – she underwent tests for her oil-burning installation at San Francisco, Santa Barbara, California, and San Diego, into March 1909. During those tests, Wyoming was renamed Cheyenne on 1 January 1909, in order to clear the name Wyoming for the projected Battleship No. 32. The ship consequently underwent more tests on her oil-burning equipment at Santa Barbara, San Pedro, and San Diego before she was placed in reserve at Mare Island on 8 June. She was decommissioned on 13 November of the same year.

Cheyenne

Recommissioned, in reserve, on 11 July 1910, Lieutenant Commander Charles Trusedale Owens in command, Cheyenne was assigned to the Washington Naval Militia in 1911 and operated in an "in commission, in reserve" status into 1913. Shifting to the Puget Sound Navy Yard early in February 1913, Cheyenne was fitted out as a submarine tender over the ensuing months. Finally, on 20 August 1913, Cheyenne was placed in "full commission". The newly converted submarine tender operated in the Puget Sound region until 11 December, when she sailed for San Francisco. In the ensuing months, Cheyenne tended the submarines of the Second Submarine Division, Pacific Torpedo Flotilla, at Mare Island, San Francisco, and San Pedro, into April 1914. Later that spring, when troubled conditions in Mexico threatened American lives and property, Cheyenne interrupted her submarine tending duties twice, once in late April and once in mid-May, to embark refugees at Ensenada, Mexico, and San Quentin, Mexico, transporting them both times to San Diego.

Cheyenne then resumed her submarine tending operations on the West Coast, continuing them into 1917. On 10 April of that year, four days after the U.S. entered World War I, she proceeded to Port Angeles, Washington, the designated point of mobilization for the Pacific Fleet, in company with the submarines USS H-1 (SS-28) and USS H-2 (SS-29), arriving there on 16 April. Subsequently, shifting to the Puget Sound Navy Yard, Cheyenne remained at that port for most of a month taking on stores and provisions loading ammunition and receiving men on board to fill the vacancies in her complement. On 28 April Cheyenne guarded USS N-1 (SS-53) as she ran trials off Port Townsend, Washington. On 4 May, the warship returned to Puget Sound for drydock and yard work. Completing that refit late in May, Cheyenne shifted southward to San Pedro, Los Angeles, where she established a submarine base and training camp for personnel for submarine duty. Cheyenne subsequently joined the Atlantic Fleet, serving as flagship and tender for Division 3, Flotilla 1, Submarine Force, Atlantic Fleet. On 17 December 1918, the ship was transferred to Division 1, American Patrol Detachment. While with that force, Cheyenne lay at Tampico, Mexico, protecting American lives and property from 16 January to 9 October 1919. Proceeding north soon thereafter, the warship arrived at the Philadelphia Navy Yard on 23 October 1919, where she was decommissioned on 3 January 1920.

While inactive at Philadelphia, the ship was classified as a miscellaneous auxiliary, under the hull number IX-4, in the fleetwide designation of alphanumeric hull classification symbols of 17 July 1920. Subsequently, recommissioned at Philadelphia on 22 September of the same year, Cheyenne was towed to Baltimore, Maryland, by the tug USS Lykens (AT-56). Based there, Cheyenne was assigned to training duty with Naval Reserve Force (USNRF) personnel of subdistrict "A" of the Fifth Naval District, and trained USNRF reservists through 1925. Based at Baltimore, she occasionally visited Hampton Roads during her cruises. On 21 January 1926, the minesweeper USS Owl (AM-2) took Cheyenne in tow and took her to Norfolk, Virginia, and thence to Philadelphia, where she arrived on 27 January for inactivation. Decommissioned on 1 June 1926, Cheyenne was struck from the Naval Vessel Register on 25 January 1937, and her stripped-down hulk was sold for scrap on 20 April 1939.

title: USS Wyoming (BM-10)


text:
Marinus van der Lubbe

Marinus van der Lubbe (13 January 1909 – 10 January 1934) was a Dutch communist who was tried, convicted, and executed by the government of Nazi Germany for setting fire to the Reichstag building—the national parliament of Germany—on 27 February 1933. During his trial, the prosecution argued that van der Lubbe had acted on behalf of a wider communist conspiracy, while left-wing anti-Nazis argued that the fire was a false flag attack arranged by the Nazis themselves. Most historians agree that van der Lubbe acted alone, although this is occasionally disputed. Nearly 75 years after the event, the German government granted van der Lubbe a posthumous pardon.

Early life
Marinus van der Lubbe was born in Leiden in the province of South Holland in the Netherlands. His parents were divorced, and after his mother died when he was twelve years old, he went to live with his half-sister's family in the town of Oegstgeest. During part of his youth van der Lubbe worked as a bricklayer. He was nicknamed Dempsey after boxer Jack Dempsey because of his great strength. While working, van der Lubbe became acquainted with the labour movement; in 1925, at age 16, he joined the Communist Party of the Netherlands (CPN) and its youth section, the Communist Youth Bund (CJB).

In 1926 he was injured at work, getting lime in his eyes, which hospitalised him for a few months and almost blinded him. Since the injury forced him to quit his job, he was unemployed with a pension of 7.44 guilders a week (roughly US$3.05 at the time, equivalent to US$52.41 in 2023). After some conflicts with his sister, van der Lubbe relocated to Leiden in 1927. There he learned to speak some German and founded the Lenin House, where he organised political meetings. While working for the Tielmann factory, a strike began. Van der Lubbe claimed to the management to be one of the ringleaders and offered to accept any punishment if no one else was punished, even though he was clearly too inexperienced to have been involved seriously. During the trial, he tried to claim sole responsibility and was purportedly hostile to the idea of not being punished.

Afterwards, van der Lubbe planned to emigrate to the USSR, but he lacked the funds to do so. He was active politically among unemployed workers until 1931, when he had a disagreement with the CPN and instead approached the Group of International Communists. In 1933, van der Lubbe fled to Germany to work for communism there. He had a criminal record for several attempted arsons.

Reichstag fire
On 27 February 1933, van der Lubbe was arrested in the Reichstag building, soon after the building had begun burning. Van der Lubbe confessed and claimed to have acted alone and have set the Reichstag building afire in an attempt to rally German workers against fascist rule.

He was tried along with the chief of the Communist Party of Germany and three members of the Bulgarian Communist Party, who were working in Germany for the Communist International. At his trial, van der Lubbe was convicted and sentenced to death for the Reichstag fire. The four other defendants (Ernst Torgler, Georgi Dimitrov, Blagoy Popov, and Vasil Tanev) were acquitted. Van der Lubbe was guillotined in a Leipzig prison yard on 10 January 1934, three days before his 25th birthday. He was buried in an unmarked grave in the Südfriedhof (South Cemetery) in Leipzig.

After World War II, attempts were made by his brother, Jan van der Lubbe, to have the original verdict reversed. In 1967, his sentence was changed by a judge from death to eight years in prison. In 1980, after more lengthy complaints, a West German court reversed the verdict entirely, but that was criticised by the state prosecutor. The case was re-examined by the Federal Court of Justice of Germany for three years. In 1983, the court made a final decision on the matter and reversed the result of the 1980 trial on grounds that there was no basis for it and so it was illegal. However, on 6 December 2007 the public prosecutor general Monika Harms nullified the entire verdict and posthumously pardoned van der Lubbe.

Claimed responsibility
Historians disagree as to whether van der Lubbe acted alone, as he said, to protest the condition of the German working class, or was involved in a larger conspiracy. The Nazis blamed a communist conspiracy. Responsibility for the Reichstag fire remains an ongoing topic of debate and research in modern historical scholarship. Journalist William Shirer, writing in 1960, surmised that van der Lubbe was goaded into setting a fire at the Reichstag but that the Nazis had set their own more elaborate fire at the same time. According to Ian Kershaw, writing in 1998, the consensus of nearly all contemporary historians is that van der Lubbe had in fact set the Reichstag afire.

Lex van der Lubbe
"Lex van der Lubbe" is the colloquial term for the Nazi law concerning the imposition and execution of the death penalty, passed on 29 March 1933. The name comes from the fact that the law formed the legal basis for the imposition of the death penalty against van der Lubbe.

The Reichstag Fire Decree of 28 February 1933 included a list of crimes for which the death penalty was to be imposed instead of a life sentence, as was previously the case. The law concerning the imposition and execution of the death penalty was passed by Hitler's government on 29 March (on the basis of the Enabling Act which had been passed on 23 March 1933). It extended the law retroactively to 31 January 1933, thereby violating Article 116 of the Weimar Constitution, which prohibited retroactive penalties. The Enabling Act itself, however, made this legislation constitutional, provided the office of the president and the Reichstag and Reichsrat were not affected. It could thus be applied to van der Lubbe, who had admitted in court that he had set fire to the Reichstag on 27 February.

The law was ultimately repealed by the Allied Control Council on 30 January 1946 through Control Council Act No. 11.

Exhumation
In January 2023, bodily remains at van der Lubbe's supposed grave were exhumed. This was done to ascertain the precise location and identity of the grave, as well as to allow for a toxicological analysis. Van der Lubbe had appeared sleepy and apathetic during his trial, resulting in suspicions that he had been drugged. These remains were determined to be van der Lubbe's after several months of forensic investigations. The toxicology report showed no evidence that van der Lubbe had been administered drugs, although it was noted that due to decomposition it is impossible to scientifically prove one way or the other and that the question remains open.

title: Marinus van der Lubbe


text:
Talk:Resignation from the House of Commons of the United Kingdom

Resignation from the British House of Commons
I seem to be lost here. Are you saying that, if an MP wants to resign his or her position, they are appointed to this seat instead? What if more than one MP wants to resign? -- Zoe

 * It's not a seat - it's an "office of the crown". Another example of an office of the crown is a judge - if an MP becomes a judge they are automatically disqualified from being an MP.  The Chiltern Hundreds office, unlike that of a judge, is not a real job but just exists to make it possible to MPs to give up their jobs.  On the question of more than one MP wanting to resign, it gets even more weird! I've changed the article accordingly. Enchanter

Yes. There is as far as I know no method of resignation, so the only way out is to become ineligible by being appointed to one of two Crown offices by taking the Chiltern Hundreds or a similar position. Once ineligible to be an MP, I presume they resign the post. If more than one wants to resign, there is a second office that can also be used. I don't know if there is a problem with a number of people taking the Chiltern Hundreds simultaneously. I suppose they could take it, at 12 noon, become ineligible for a Commons seat there and then, resign from the Stewardship of the Chiltern Hundreds at 12.01 and the someone else take it at 12.02 etc. JtdIrL 02:40 Mar 6, 2003 (UTC)

 * You guessed right - what a bizarre system! It's a weird country I live in...  Enchanter

Heh heh. Oh I don't know. I am a bit of a sucker for tradition and all that stuff. Beats some MP jumping up and saying 'I'm off'!!! JtdIrL 03:04 Mar 6, 2003 (UTC)

It seems that the ban on resignations dates from the early 17th century, when serving in Parliament was a slightly onerous task (having to drag yourself down to London in the days before cars and trains), not to mention a dangerous one (risk of disagreements with the King). The Chiltern Hundreds is a loophole that has turned into an institution. --rbrwr

 * At one time all Ministers had to resign on appointment and then get re-elected.  The Chancellor of the Exchequer appoints resigning MPs to the Chiltern Hundreds or Manor of Northstead alternately, and the letter  of appointement includes the dismissal of the previous holder. When the laws were changed in 1919 and 1926 (it took two attempts to modernise things) only ministers were exempted, so Chiltern Hundreds & Manor of Northstead were satill offices of profit.  The last time an MP "resigned" without dying or becoming a peer was 1981, when someone was made a judge.  garryq 19:43, 22 Apr 2004 (UTC)

Anyone know what the "salary" of a steward is? garryq 19:43, 22 Apr 2004 (UTC)

 * As of 1829 it was one pound, but I can't find anything more recent. Marnanel 20:22, Apr 22, 2004 (UTC)

 * There is no salary. It is purely notional. Dbiv 21:51, 26 Sep 2004 (UTC)

I find this article pretty confusing; it presupposes a fair bit of understanding of the UK parlimentary system. I gather that (please check me on this), if one is elected, there are then the following ways to no longer be an MP: Have I got all that right?
 * die
 * some mechanism involving the peerage; formerly, just acceding to a title would do it, since that made one a member of the house of lords. now, with the house of lords in some sort of intermediate state, I'm unclear.
 * accept some other real job that might involve a conflict of interest. this includes becoming a judge. anything else? it used to include becoming a cabinet minister, but since 1926 no longer does.
 * ask to be appointed to one of the fake jobs (Chiltern or Northstead), whose whole purpose for existing is to provide a way to resign.

Now, what happens if an MP is too ill to continue? Do they use the Chiltern/Northstead or is there some other way that's handled?

Weirder questions: Could the chancellor of the exchequer refuse to appoint someone to the fake posts, forcing them to remain in office? Could someone, once appointed to a fake post, sue to be retained as an MP on the basis that Chiltern and Northstead do not, in fact, pay salaries?

-- Akb4 15:16, 26 August 2006 (UTC)

Can I enter a formal protest against the use of navboxes for the Stewards of the Chiltern Hundreds and Manor of Northstead. They are seriously confusing to anyone who is not familiar with British politics. These posts in their modern usage have no salary, carry no responsibilities, involve no burdens, impose no duties, and to all intents and purposes they do not exist. To quote someone as having held the office of Steward of the Chiltern Hundreds for four years would imply to an outsider that they held a post of honour or a job for this amount of time when the only significance was momentary in enabling them to divest themself of a seat in the House of Commons. It is also difficult to get information on previous appointments which is why there are only 34 of the navboxes in use anyway - of which the earliest relates to 1972.

I think that these navboxes should be removed. If people want information on who was appointed as Steward and when, perhaps List of Stewards of the Chiltern Hundreds and List of Stewards of the Manor of Northstead can be written. Anyone with the Blue Book list of Members of Parliament could compile a list going back to the 1750s which might make interesting reading. Dbiv 22:09, 26 Sep 2004 (UTC)

 * It actually seems illogical to state that the offices are 'held', other than momentarily. Those who take them are able to stand in the ensuing byelection (Robert McCrea, Enoch Powell and Bruce Douglas-Mann for instance) and nobody seems to have objected that they were disqualified. It would be nice to have a 'see also' wiki link to this page if the navboxes are removed. --Keith Edkins 06:33, 27 Sep 2004 (UTC)

 * See above. It is the same as it used to be with Ministers - appointment to the office was the disqualification, but Stewards (just like Ministers) could be re-elected. User:80.229.39.194

 * But it is not like a Minister. A Minister has to do a job, and gets a salary, and if their performance is not up to scratch they get sacked. The Steward of the Chiltern Hundreds gets no salary and doesn't do anything, and can't get sacked. They are chalk and cheese.Dbiv 22:26, 27 Sep 2004 (UTC)

 * Well technically, couldn't someone get sacked from one of the resignation positions? ugen64 00:52, Sep 29, 2004 (UTC)
 * Yes. I suppose they would have to do that if the member was resigning for a third time (á la Mandelson—OK, that was as a minster) so held both resignation posts. Although if the prohibition doesn't include re-accepting an office one had before the election, they would have to have the first resignation post removed before re-standing the first time following resignation).
 * Joe Llywelyn Griffith Blakesley talk contrib 00:25, 24 July 2006 (UTC)

Beattie?
This entry states
 * The prohibition was on an MP accepting an office of profit under the Crown, but it did not disqualify someone with such an office being elected to the House of Commons.

So what happened to Charles Beattie in Mid-Ulster in 1955? He was apparently disqualified for holding an office of profit at the time of his election.

So there is some inconsistency with the previous statement which needs clarifying, methinks.... RodCrosby 19:55, 26 March 2006 (UTC)

John Pitt
"The Chiltern Hundreds were first used as a pretext for resignation on January 17, 1751, by John Pitt, who wanted to vacate his seat for Wareham and stand for Dorchester."

That can't be correct. John Pitt wasn't born until 1756!!

Why
I read in this article:
 * In 1623 a rule was declared that said that members of Parliament were given a trust to represent their constituencies, and therefore were not at liberty to resign them.

If it since has become possible to resign by being appointed Steward of something, and thus the substance of this 1623 rule was lost, why hasn't the rule been changed?

Why not make a new rule saying that an MP that does not want to be an MP any longer can resign from the seat?

Is that for the love of old traditions or is there some constitutional problem why that rule cannot be changed? Johan Lont 11:01, 5 September 2007 (UTC)

 * This is simply one of the many legal fictions which underpin the British constitution. I take it that this is simply out of a love of tradition as s.4 of the House of Commons Disqualification Act 1974 explicitly preserved this method of resignation.  If you wanted to look into it a little more deeply you could consult the relevant Hansard debates and see if there were any arguments presented for/against a dedicated resignation procedure.  To the best of my knowledge though there is no constitutional reason it cannot be changed - Parliament has the power to alter all laws in any way, so any problem that would arise by the establishment of a resignation procedure could be fixed by Parliament.

 *  X damr  talk 14:23, 5 September 2007 (UTC)
 * Thank you for this information. Johan Lont 11:41, 7 September 2007 (UTC)

Succession boxes
An issue has come up regarding the presence of succession boxes for the offices of Steward of the Chiltern Hundreds and Manor of Northstead. Some editors have been adding them while others feel they are misleading.

This is an example of the box:

Supporters regard the boxes as harmless, interesting and helpful. Opponents regard them as potentially misleading, because the offices are a legal fiction. The views of a wider group of editors are sought. Sam Blacketer (talk) 10:48, 2 July 2008 (UTC)

 * My comments from the discussion on this before centralising it:

 * The key point is that these offices are entirely nominal and are operated purely as a mechanism to allow a sitting MP to resign. That the office is non-existent beyond appointment and often misunderstood is shown by David Davis explicitly resigning the Chiltern Hundreds for his by-election apparently due to uncertainty over whether he would be eligible to stand otherwise when there's no evidence that Enoch Powell, William McCrea, Bruce Douglas-Mann, Dick Taverne or Sir Richard Acland (and other cases before the war) ever resigned the notional office in identical circumstances. (The other 1985 Unionist MPs had no dilemma as their fellows immediately succeeded them.) Certainly the resigning MPs never have anything to do with Scarborough or Stoke, Desborough & Burnham. The box is misleading because for anyone looking at the article it appears the ex MP held a position of any meaning for a period of time when there is no salary, no duties and no fancy title attached. Timrollpickering (talk) 20:07, 2 July 2008 (UTC)
 * i think whilst people 'in the know' understand them, and maybe appreciate them, the vast majority of editors (let alone readers) don't have a clue what the positions mean. given their relative insignificance compared to other positions held, and uncertainty about how long they are even held for, we will be better off without the box. [on a side note: what i remember (SLD won't load at all) from the House of Commons Disqualification Act 1975 means you would definitely have to resign the office to take up your seat - but i know not when your cited examples were from?] ninety:one 20:49, 2 July 2008 (UTC)

 * Acland resigned in 1955 over Labour's policy on nuclear weapons (although the general election overtook his planned by-election), Taverne in 1973 over the left-wing takeover of his Constituency Labour Party (sort of a proto Social Democratic Party movement), Bruce Douglas-Man in 1982 when he moved from Labour to the SDP and Powell & McCrea were the last of the 15 Unionist MPs to be formally appointed to the Chilterns/Northstead in December 1985 when they all opted to put themselves for re-election in a "referendum" on the Anglo-Irish Agreement. There is a huge amount of confusion even amongst MPs and candidates themselves about what offices do and don't disqualify a person and when they have to relinquish such offices by (and whether the disqualification is against being a formally nominated candidate, an elected MP or one who has taken the oath) which complicates things further although it's only an issue for three articles (Douglas-Mann, Powell and McCrea) if they ever did get advice on the matter. Certainly historically the appointment to an office of profit from the Crown only affected the existing electoral mandate, as shown by the numerous ministerial by-elections from c1701-1926. Timrollpickering (talk) 22:00, 2 July 2008 (UTC)
 * pre-1955 is quite murky, because the acts before the 1975 are uncertain - i found several references to non-existent acts. as the law stands, there is nothing to prevent a person standing for election save their citizenship. if that person wins, the high court has to overturn the election and it must be re-held. however, i'm not sure how an acting returning officer could stop someone for continuously entering... —Preceding unsigned comment added by Ninetyone (talk • contribs)
 * A court can rule that a candidate's ineligibility is known about and award the seat to the runner-up. This happened in Bristol South East in 1961, when the sitting MP inherited a peerage but wanted to remain an MP and so contested the by-election, and Fermanagh & South Tyrone in the 1955 general election where a prisoner was elected and unseated on petition to the courts. Timrollpickering (talk) 11:00, 20 July 2008 (UTC)

(unindent) My view, for what it's worth, is that succession boxes are there to allow readers to move quickly through the biographies of people who have done the same job, in order to compare and contrast how they did it. For instance, the successive holders of the job of Chancellor of the Exchequer have had different approaches to economic and monetary policy, and being able to go from one to another allows the reader to build up a picture of how things changed and developed. This even applies to more tenuous linkages, for instance there is a succession box for people killed in Formula 1 motor racing which allows comparison of safety changes and where they failed.

Seen from this perspective, succession boxes for the notional 'Crown Stewardships' used to resign seats are otiose. There is no job of Steward of the Chiltern Hundreds, just a legal fiction title which harks back to history. One cannot therefore compare and contrast how the notional holders of the title performed in office, because there was no office they were in. Nor is it actually a succession box for MPs who have resigned, since the two jobs of the Chiltern Hundreds and the Manor of Northstead appear to alternate; the link is to the last-but-one MP to resign.

Providing a succession box makes it look to a listener unfamiliar with this field as though it was a real job, and it can hardly be said that there are many people who are aware exactly what the situation is with MPs resigning. Indeed it isn't really enough to follow the link to the list of Stewards, because the real explanation is on Resignation from the British House of Commons, so readers have to follow two links. I therefore think these succession boxes should go; it's fine to mention in the text of the article that the MP concerned 'resigned by being appointed Steward of the Chiltern Hundreds' etc, if a link to the appointment is wanted. Sam Blacketer (talk) 10:16, 3 July 2008 (UTC)
 * As I have said before, my main feelings are that succession boxes allows people to see how long people held it, and I think seeing who succeded them is useful. It may only be a legal fiction, but I still believe that it is a harmless, interesting and helpful addition to the succession boxes. I don't think it is misleading in anyway, as the articles (Northstead or Chiltern) makes it clear, and those articles are linked from succession box - I always link to the article on the position, rather than the list of holders, so the person can quickly see the purpose of the title. I don't think it will confuse people, as the article on the MP itself should give a quick explanation, and the link is also there. I believe it's a useful and harmless addition to the article.--UpDown (talk) 07:12, 7 July 2008 (UTC)

Could we not put "nominally" in the succession boxes (perhaps with a link to legal fiction), to make it clear to those not familiar with the positions that they're not substantive offices. Something like this, perhaps. Proteus (Talk) 08:56, 7 July 2008 (UTC)

 * Yeah, that sounds like a very good idea to me, and it looks fine.--UpDown (talk) 17:25, 7 July 2008 (UTC)
 * link to this page instead, Legal fiction is quite general. ninety:one 20:28, 7 July 2008 (UTC)
 * Yes I can see what you mean. I'd be more than happy with this.--UpDown (talk) 07:11, 8 July 2008 (UTC)
 * Thinking over this again, what really rankles with me is the date span - because it's arbitrary. If instead of the span of dates, the box just had the date of appointment, it wouldn't look half so out of place. Can this be done? Sam Blacketer (talk) 13:35, 8 July 2008 (UTC)
 * Personally one of the things I like most are the dates, I think they are useful and interesting to the reader. If we only to put the appointment date, then this would have to be clearly stated, otherwise we might give the impression the MP held it only for one day. But, I would like to see the dates stay.--UpDown (talk) 07:26, 9 July 2008 (UTC)

The succession boxes seem unnecessary, and undesirable as potentially confusing as they imply it's a real job. All that's needed is a link to Resignation from the British House of Commons and a link to List of Stewards of the Chiltern Hundreds or the Northstead list. But it would be better if the link from the "List of Stewards..." to "Resignation..." was more obvious, rather than just a piped link from the simple word "resignation". PamD (talk) 08:14, 20 July 2008 (UTC) They may not be causing any serious harm, but on the whole I think we are better off without them. PatGallacher (talk) 01:44, 30 July 2008 (UTC)
 * Disagree with both of them. They are useful to the reader and put correctly, not misleading.--UpDown (talk) 11:05, 4 November 2008 (UTC)

Steward of the Manor of Poynings
The only Lord Montague dying c1804 I can find is Edward Hussey-Montagu, 1st Earl Beaulieu d. Nov 1802. Is this the right Montagu to link to? Bazj (talk) 11:16, 19 April 2009 (UTC)

Historical inaccuracy
There was no "British" House of Commons until 1707, or was there? Anyway, the reference to 16?? is to the English HoC.--MacRusgail (talk) 14:53, 31 July 2009 (UTC)

Are they really "forbidden to resign"?
Members of Parliament sitting in the House of Commons in the United Kingdom are technically forbidden to resign ...

Is this really so? An MP who thinks "Stuff this stupid rigmarole, I'm just going to quit", and then signs a letter of resignation and hands it to the Speaker, would find that their purported "resignation" is of nil effect and they are still very much an MP. In other words, it's simply not possible to unilaterally resign, thus the idea of prohibiting an impossibility is a little silly. It's not like it's technically possible but outlawed, in the way murder is. It's not like an MP can break the rules and resign anyway, and get whatever penalty comes from such a breach. There is no penalty, because there can be no breach, because it's impossible in the first place. This is my understanding. Am I correct? --  Jack of Oz    ... speak! ...   12:04, 18 June 2010 (UTC)
 * They are forbidden under a resolution passed in 1624. I don't know if it is related, but the resolution is from the same year that Lionel Cranfield, 1st Earl of Middlesex was impeached. It was possibly seen as a good idea to block resignation of others with positions in Parliament so that they couldn't avoid impeachment proceedings, though that is pure speculation on my part. Road Wizard (talk) 13:37, 18 June 2010 (UTC)

 * Thanks, Road Wizard. I still think my point remains, though.  An MP who tried to "resign" would get nowhere, and would have to resort to applying for the Chiltern Hundreds or whatever.  Isn't this so?  Resignation is not so much "forbidden" as "impossible".
 * I guess a disgruntled MP could simply announce he's leaving, stop turning up at Westminster, stop dealing with constituents, and go and have a long holiday in Bermuda. As far as he's concerned, he's out of there - but the Parliament could sanction him and ultimately expel him on the grounds that he's a sitting MP who's broken the attendance rules.  The outcome is the same in the end - he's no longer an MP, but there's a measure of public disgrace attached to this method.  I'm not saying that a sane MP would do this, just shooting the breeze here. --   Jack of Oz    ... speak! ...   22:44, 18 June 2010 (UTC)
 * Well, it is only impossible because it is forbidden. In a similar way to me not being allowed to steal something because it is against the law an MP cannot resign because that too is against the law as set out in 1624. If it wasn't forbidden then there would be nothing to stop the MP from handing in a letter of resignation to the speaker or other parliamentary authorities. It is the prohibition that creates the impossibility.
 * If resignation wasn't forbidden there would be no need for such arcane practices as appointing people to token offices like the Crown Steward and Bailiff of the Chiltern Hundreds.
 * Your analogy of an MP not turning up doesn't quite work as they are still held to the same rules, laws and standards whether they are in Westminster or not. For example, if an MP doesn't bother to go to Westminster but accepts undeclared gifts from a foreign donor they could still be found guilty of electoral fraud or other corruption charges. Road Wizard (talk) 23:19, 18 June 2010 (UTC)
 * Jack, you probably thought your example was farcical but allow me to introduce Margaret Moran, who jacked it all in in May 2009 following some fairly criminal expense revelations. She didn't turn up for a year but kept her pay, expenses and got a golden goodbye at the last election! ninety:one  23:40, 18 June 2010 (UTC)

 * In reply to Road Wizard 13:37, 18 June 2010 (UTC) re Cranfield impeachment:
 * Maybe, but the 1624 resolution seems to have arisen from a more mundane case, so it was a subtle ploy if so!
 * This is the text of the official record of the discussion leading to the resolution ( emphasis added ):
 * Northumberland Election.
 * Mr. Glandvile reports from the Committee of Privileges . – Divers Petitions. – Sir Will. Gray, chosen Knight for Northumberland, since made a Baron.
 * Southwark Election.
 * Next, the Case of the Borough of Southwarke. – Twenty to Twenty. One of the Committee mis-writ, so had not his Voice.
 * Agreed –
 * Three Persons agreed to be put in Election; Mingy, Yarrow, Bromfeild. – Yarrowd one, without Question. Some of the Burgesses. –
 * Two Indentures returned : Yarrowd in both. Question for other Two. All held this a void Return, for the In-certainty. For the Election, thus: Pretended, Mr. Mingy should use indirect Passages, by keeping out the Burgesses; but this not proved. Again said, the Indenture rased; but this appeared not neither. Mingy brought a Witness or Two, that he the most Voices, upon Oath : One Witness to the contrary; who said, Mingy most Voices at first, but after not, when a Course taken for Discovery, Mingy offered to give them Thanks : They cryed, " for nought;" and cryed, "No Mingy." – One Circumstance more: – Charged Mr. Bromfeild, that his Indenture antedated. – The Sense of the Committee, that, if the Election due, that no Misdemeanor. Bromfeild offered to relinquish to Mingy, but that not enough after he was chosen . – Leaves the Consideration of this to the House.
 * Agreed also [a], that a Man, after he is duly chosen, cannot relinquish.
 * Sir Edw. Coke. – Oath on both Sides. – To have a new Writ, and refer it to the Burgesses.
 * Ordered, That the Election and Return of Mr. Yarrow shall stand good, and that he shall sit in the House; and that a new Writ shall go down, for a new Election of another Burgess.
 * — Journal of the House of Commons, 2 March 1624
 * At the time, Southwark returned two MPs. As I understand it, the record shows that:
 * Yarrow's election was undisputed;
 * there was a dispute as to whether Mingy or Bromfeild had won the other seat because two differing returns were given to the writ of election;
 * Bromfeild offered the seat to Mingy;
 * the Committee of Privileges ruled Bromfeild's offer invalid because:
 * (implicitly) if Bromfeild had not won, he had no seat to offer, and
 * even if Bromfeild were judged to have won the seat, the Committee (on behalf of the House) did not permit members to relinquish (i.e. to resign);
 * the House decided that the second seat was vacant because of the alleged irregularities and so a by-election should be held;
 * because Bromfeild was judged not to have held the seat, the Committee's resolution that seats cannot be relinquished became irrelevant to the case, but was allowed to stand as a record of the House's general rule (which was presumably widely assumed at that date though perhaps previously unwritten).
 * So the prohibition seems to rest on a committee resolution of nearly 400 years ago, although the rule's subsequent observance is the important factor in practice since; many other resolutions have no doubt been forgotten or considered obsolete with the passage of time.
 * The current legislation does not refer explicitly to resignation, but confirms that members vacate their seats if they are appointed to "the office of steward or bailiff of Her Majesty's three Chiltern Hundreds of Stoke, Desborough and Burnham, or of the Manor of Northstead" (section 4).
 * The offices are formally in the gift of the Chancellor of the Exchequer so presumably it is only constitutional convention that prevent a Chancellor from disqualifying MPs against their will.
 * — Richardguk (talk) 00:16, 19 June 2010 (UTC)

So, to return to the underlying issue, since "resignation" is simply not available, we're purporting to have an article on an impossibility. Would it not be better to call this article "Voluntary departure/withdrawal from the British House of Commons" or "Voluntary relinquishing of membership of the British House of Commons", or something like that? --  Jack of Oz   [your turn]  21:36, 10 February 2011 (UTC)
 * No, because it is a resignation in every possible way apart from the technical procedure used. It is always described as "resignation" from the House, and any "technically correct" title would be so artificially contorted to be utterly confusing. ninety:one  15:33, 11 February 2011 (UTC)

 * Well, why do we start out saying they're "... technically forbidden to resign. To circumvent this prohibition, a legal fiction is used."? I see it as quite starkly different from a resignation - that is where the member would (were it possible to do so) write a letter of resignation, hand it the Speaker, and he's out of there, end of story.  What they have to do instead is arrange their affairs so that they become ineligible to remain a member.  They could do this in a number of ways, including becoming bankrupt or committing an act of treason, but the simplest way is to apply to be appointed to a special office of profit, and await approval for the appointment (it's never refused, but it still requires formal approval, which takes as long as it takes).  In principle it's hugely different from the unilateral and instantaneous resignation procedure that applies most everywhere else.  --   Jack of Oz   [your turn]  21:57, 11 February 2011 (UTC)

Gerry Adams
From what I have read Adams could be expelled without having to go through the usual resignation procedure of applying for the office of the Crown if he actually went to the Commons and took his seat as he has not taken the Oath. Could someone validate this for me? --Charlie Huang 【遯卋山人】 21:23, 24 January 2011 (UTC)
 * I also believe it would be possible for George Osborne to go ahead and appoint Adams to the Manor of Northstead, even though Adams hasn't formally requested it. Adams has made it clear he wants to resign, and the Member's "request" for such appointment is really just a convention within a convention. The House of Commons Disqualification Act 1975, section 8, specifically gives a Member the right to refuse any appointment that would disqualify him against his wishes. So Osborne should just go ahead. RodCrosby (talk) 01:29, 26 January 2011 (UTC)
 * Sitting without taking the oath automatically disqualifies you, and makes you liable for a £500 fine for every offence. Parliamentary Oaths Act 1866. -  Chrism  would like to hear from you 14:10, 29 January 2011 (UTC)

The King's Displeasure
As I understand it, back when the king commanded more power than the House of Commons, the House felt that they must all stand together, or they would be helpless. For this reason the rule is that a decision of the House is a decision of the whole House. (The convention in the House of Lords was that every member was a great man in the state, and entitled to have his opinion recorded for posterity.) If the king wanted something (probably money) from the Commons, and they were disobliging, he might harass the indocile members into resigning, and get himself a submissive House. For this reason the Commons refuse to allow a member to resign without permission of the House, which is never granted except to a member who is TERMINALLY ill.

This former weakness of the Commons is responsible for a couple of other strange fossils. As far as I know, it is still illegal to publish the debates and votes in the House of Commons unless the House so orders (now a routine matter). There is a rule against taking notes on the debates for possible tale-bearing to the king, and the speaker, if he sees anyone doing it, must order the offender put out of the chamber. The press box is therefore right behind the speaker, where he can't see them and officially doesn't know what they are doing. J S Ayer (talk) 17:42, 20 March 2014 (UTC)

McGuinness letter?
A picture purporting to be of McGuinness's actual resignation letter is on the internet here. It says in full:
 * A chara, I hereby resign as M.P. for the Mid Ulster constituency. In the process of my resignation I will not accept any office of profit under the crown. Martin McGuinness

I don't know if this is a genuine image; if it could be verified as such, I think it would be worth quoting, even though it is a primary source. jnestorius(talk) 22:19, 11 June 2015 (UTC)

"Office of profit under the Crown"
Section 1(4) of the House of Commons Disqualification Act 1975 reads: "Except as provided by this Act, a person shall not be disqualified for membership of the House of Commons by reason of his holding an office or place of profit under the Crown or any other office or place; and a person shall not be disqualified for appointment to or for holding any office or place by reason of his being a member of that House."

So holding an "office of profit under the Crown" is actually no longer an impediment to being an MP. Nonetheless, the Bailiffs of the Chiltern Hundreds and the Manor of Northstead are still disqualified, but only specifically by virtue of section 4 of that Act: "For the purposes of the provisions of this Act relating to the vacation of the seat of a member of the House of Commons who becomes disqualified by this Act for membership of that House, the office of steward or bailiff of Her Majesty’s three Chiltern Hundreds of Stoke, Desborough and Burnham, or of the Manor of Northstead, shall be treated as included among the offices described in Part III of Schedule 1 to this Act."

Part III of Schedule 1 is the schedule that lists specific offices that are disqualified by s. 1(1)(f). Hairy Dude (talk) 19:54, 30 August 2016 (UTC)


text:
Vegetable oil

Vegetable oils, or vegetable fats, are oils extracted from seeds or from other parts of edible plants. Like animal fats, vegetable fats are mixtures of triglycerides. Soybean oil, grape seed oil, and cocoa butter are examples of seed oils, or fats from seeds. Olive oil, palm oil, and rice bran oil are examples of fats from other parts of plants. In common usage, vegetable oil may refer exclusively to vegetable fats which are liquid at room temperature. Vegetable oils are usually edible.

The health effects of vegetable oil consumption have been the subject of numerous studies. A systematic review in 2015 found that consumption of virgin olive oil significantly reduced cardiovascular disease.

In antiquity
Olive oil has been a part of human culture for millennia. Archaeological evidence shows that olives were turned into olive oil by 6000 BC and 4500 BC in present-day Israel. Pagnol, p. 19, says the 6th millennium in Jericho, but cites no source. In ancient Egypt, plant oils including cedar oil, cypress oil, and olive oil were used during the mummification process.

Vegetable oils have been used as lighting fuel for lamps, cooking, medicine and lubrication. Palm oil has long been recognized in West and Central African countries, and European merchants trading with West Africa occasionally purchased palm oil for use as a cooking oil in Europe. It became highly sought-after commodity by British traders for use as an industrial lubricant for machinery during Britain's Industrial Revolution.

Modern history
Palm oil formed the basis of soap products, such as Lever Brothers' (now Unilever) "Sunlight", and B. J. Johnson Company's (now Colgate-Palmolive) "Palmolive," and by around 1870, palm oil constituted the primary export of some West African countries.

In 1780, Carl Wilhelm Scheele demonstrated that fats were derived from glycerol. Thirty years later Michel Eugène Chevreul deduced that these fats were esters of fatty acids and glycerol. Wilhelm Normann, a German chemist introduced the hydrogenation of liquid fats in 1901, creating what later became known as trans fats, leading to the development of the global production of margarine and vegetable shortening.

In the United States, cottonseed oil was developed, and marketed by Procter & Gamble as a creamed shortening – Crisco – as early as 1911. Ginning mills were happy to have someone haul away the cotton seeds. The extracted oil was refined and partially hydrogenated to give a solid at room temperature and thus mimic natural lard, and canned under nitrogen gas. Compared to the rendered lard Procter & Gamble was already selling to consumers, Crisco was cheaper, easier to stir into a recipe, and could be stored at room temperature for two years without turning rancid.

Soybeans are protein-rich, and the medium viscosity oil rendered from them was high in polyunsaturates. Henry Ford established a soybean research laboratory, developed soybean plastics and a soy-based synthetic wool, and built a car "almost entirely" out of soybeans. Roger Drackett had a successful new product with Windex, but he invested heavily in soybean research, seeing it as a smart investment. By the 1950s and 1960s, soybean oil had become the most popular vegetable oil in the US; today it is second only to palm oil. In 2018–2019, world production was at 57.4 MT with the leading producers including China (16.6 MT), US (10.9 MT), Argentina (8.4 MT), Brazil (8.2 MT), and EU (3.2 MT).

The early 20th century also saw the start of the use of vegetable oil as a fuel in diesel engines and in heating oil burners. Rudolf Diesel designed his engine to run on vegetable oil. The idea, he hoped, would make his engines more attractive to farmers who had a source of fuel readily available. Diesel's first engine ran on its own power for the first time in Augsburg, Germany, on 10 August 1893 on nothing but peanut oil. In remembrance of this event, 10 August has been declared "International Biodiesel Day". The first patent on Biodiesel was granted in 1937. Periodic petroleum shortages spurred research into vegetable oil as a diesel substitute during the 1930s and 1940s, and again in the 1970s and early 1980s when straight vegetable oil enjoyed its highest level of scientific interest. The 1970s also saw the formation of the first commercial enterprise to allow consumers to run straight vegetable oil in their vehicles. However, biodiesel, produced from oils or fats using transesterification is more widely used. Led by Brazil, many countries built biodiesel plants during the 1990s, and it is now widely available for use in motor vehicles, and is the most common biofuel in Europe today. In France, biodiesel is incorporated at a rate of 8% in the fuel used by all French diesel vehicles.

In the mid-1970s, Canadian researchers developed a low-erucic-acid rapeseed cultivar. Because the word "rape" was not considered optimal for marketing, they coined the name "canola" (from "Canada Oil low acid"). The U.S. Food and Drug Administration approved use of the canola name in January 1985, and U.S. farmers started planting large areas that spring. Canola oil is lower in saturated fats, and higher in monounsaturates. Canola is very thin (unlike corn oil) and flavorless (unlike olive oil), so it largely succeeds by displacing soy oil, just as soy oil largely succeeded by displacing cottonseed oil.

The production of vegetable oils went up 125% between 2000 and 2020, driven by a sharp increase in palm oil.

Culinary
Many vegetable oils are consumed directly, or indirectly as ingredients in food – a role that they share with some animal fats, including butter, ghee, lard, and schmaltz. The oils serve a number of purposes in this role:
 * Shortening – as in giving pastries a crumbly texture.
 * Enriching – adding calories and satisfaction in consumption
 * Texture – altering how ingredients combine, especially fats and starches
 * Flavoring – examples include olive, sesame, or almond oil
 * Flavor base – oils can also "carry" flavors of other ingredients, such as peppers, since many flavors are due to chemicals that are soluble in oil.

Oils can be heated to temperatures significantly higher than the boiling point of water, 100 C, and used to fry foods. Oils for this purpose must have a high flash point. Such oils include both the major cooking oils – soybean, rapeseed, canola, sunflower, safflower, peanut, cottonseed, etc. – and tropical oils, such as coconut, palm, and rice bran. The latter are particularly valued in Asian cultures for high-temperature cooking, because of their unusually high flash points.

Industrial
Vegetable oils are used as an ingredient or component in many manufactured products.

Many vegetable oils are used to make soaps, skin products, candles, perfumes and other personal care and cosmetic products. Some oils are particularly suitable as drying oils, and are used in making paints and other wood treatment products. They are used in alkyd resin production. Dammar oil (a mixture of linseed oil and dammar resin), for example, is used almost exclusively in treating the hulls of wooden boats. Vegetable oils are increasingly being used in the electrical industry as insulators as vegetable oils are not toxic to the environment, biodegradable if spilled and have high flash and fire points. However, vegetable oils are less stable chemically, so they are generally used in systems where they are not exposed to oxygen, and they are more expensive than crude oil distillate. Synthetic tetraesters, which are similar to vegetable oils but with four fatty acid chains compared to the normal three found in a natural ester, are manufactured by Fischer esterification. Tetraesters generally have high stability to oxidation and have found use as engine lubricants. Vegetable oil is being used to produce biodegradable hydraulic fluid and lubricant.

One limiting factor in industrial uses of vegetable oils is that all such oils are susceptible to becoming rancid. Oils that are more stable, such as ben oil or mineral oil, are thus preferred for industrial uses. Castor oil has numerous industrial uses, owing to the presence of a hydroxyl group on the fatty acid. Castor oil is a precursor to Nylon 11. Castor oil may also be reacted with epichlorohydrin to make a glycidyl ether which is used as a diluent and flexibilizer with epoxy resins.

Pet food additive
Vegetable oil is used in the production of some pet foods. AAFCO defines vegetable oil in this context as the product of vegetable origin obtained by extracting the oil from seeds or fruits which are processed for edible purposes.

Fuel
Vegetable oils are also used to make biodiesel, which can be used like conventional diesel. Some vegetable oil blends are used in unmodified vehicles but straight vegetable oil, also known as pure plant oil, needs specially prepared vehicles which have a method of heating the oil to reduce its viscosity. The use of vegetable oils as alternative energy is growing and the availability of biodiesel around the world is increasing.

The NNFCC estimates that the total net greenhouse gas savings when using vegetable oils in place of fossil fuel-based alternatives for fuel production, range from 18 to 100%.

Production
The production process of vegetable oil involves the removal of oil from plant components, typically seeds. This can be done via mechanical extraction using an oil mill or chemical extraction using a solvent. The extracted oil can then be purified and, if required, refined or chemically altered.

Mechanical extraction
Oils can be removed via mechanical extraction, termed "crushing" or "pressing". This method is typically used to produce the more traditional oils (e.g., olive, coconut etc.), and it is preferred by most health-food customers in the United States and in Europe. There are several different types of mechanical extraction. Expeller pressing extraction is common, though the screw press, ram press, and ghani (powered mortar and pestle) are also used. Oilseed presses are commonly used in developing countries, among people for whom other extraction methods would be prohibitively expensive; the ghani is primarily used in India. The amount of oil extracted using these methods varies widely, as shown in the following table for extracting mowrah butter in India:

Solvent extraction
The processing of vegetable oil in commercial applications is commonly done by chemical extraction, using solvent extracts, which produces higher yields and is quicker and less expensive. The most common solvent is petroleum-derived hexane. This technique is used for most of the "newer" industrial oils such as soybean and corn oils. After extraction, the solvent is evaporated out by heating the mixture to about 300 F.

Supercritical carbon dioxide can be used as a non-toxic alternative to other solvents.

Hydrogenation
Unsaturated vegetable oils can be transformed through partial or complete hydrogenation into oils of higher melting point, some of which, such as vegetable shortening, will remain solid at room temperature.

Hydrogenating vegetable oil is done by raising a blend of vegetable oil and a metal catalyst, typically nickel, in near-vacuum to very high temperatures, and introducing hydrogen. This causes the carbon atoms of the oil to break double-bonds with other carbons. Each carbon atom becomes single-bonded to an individual hydrogen atom, and the double bond between carbons can no longer exist. A fully hydrogenated oil, also called a saturated fat, has had all of its double bonds converted into single bonds. If a polyunsaturated oil is left incompletely hydrogenated (not all of the double bonds are reduced to single bonds), then it is a "partially hydrogenated oil" (PHO). An oil may be hydrogenated to increase resistance to rancidity (oxidation) or to change its physical characteristics. As the degree of saturation is raised by full or partial hydrogenation, the oil's viscosity and melting point increase.

While full hydrogenation produces largely saturated fatty acids, partial hydrogenation results in the transformation of unsaturated cis fatty acids to unsaturated trans fatty acids in the oil mixture due to the heat used in hydrogenation. Partially hydrogenated oils and their trans fats have been linked to an increased risk of mortality from coronary heart disease, among other increased health risks. These concerns have led to regulations mandating the removal of partially hydrogenated oils from food.

Deodorization
In the processing of edible oils, the oil is heated under vacuum to near the smoke point or to about 450 F, and water is introduced at the bottom of the oil. The water immediately is converted to steam, which bubbles through the oil, carrying with it any chemicals which are water-soluble. The steam sparging removes impurities that can impart unwanted flavors and odors to the oil. Deodorization is key to the manufacture of vegetable oils. Nearly all soybean, corn, and canola oils found on supermarket shelves go through a deodorization stage that removes trace amounts of odors and flavors, and lightens the color of the oil. However, the process commonly results in higher levels of trans fatty acids and distillation of the oil's natural compounds.

Occupational exposure
People can breathe in vegetable oil mist in the workplace. The U.S. Occupational Safety and Health Administration (OSHA) has set the legal limit (permissible exposure limit) for vegetable oil mist exposure in the workplace as 15 mg/m3 total exposure and 5 mg/m3 respiratory exposure over an 8-hour workday. The U.S. National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of 10 mg/m3 total exposure and 5 mg/m3 respiratory exposure over an 8-hour workday.

Yield
Typical productivity of some oil crops, measured in tons (t) of oil produced per hectare (ha) of land per year (yr). Oil palm is by far the highest yielding crop, capable of producing about 4 tons of palm oil per hectare per year.

Particular oils
The following triglyceride vegetable oils account for almost all worldwide production, by volume. All are used as both cooking oils and as SVO or to make biodiesel. According to the USDA, the total world consumption of major vegetable oils in 2007/08 was:

These figures include industrial and animal feed use. The majority of European rapeseed oil production is used to produce biodiesel, or used directly as fuel in diesel cars which may require modification to heat the oil to reduce its higher viscosity.

Other significant oils include:

 * Corn oil, one of the most common cooking oils, is used for cooking oil, salad dressing, margarine, mayonnaise, prepared goods like spaghetti sauce and baking mixes, and to fry prepared foods like potato chips and French fries.
 * Grape seed oil, used in cooking and cosmetics
 * Hazelnut oil and other nut oils
 * Linseed oil, from flax seeds
 * Rice bran oil, from rice grains
 * Safflower oil, a flavorless and colorless cooking oil
 * Sesame oil, used as a cooking oil, and as a massage oil, particularly in India
 * Açaí palm oil, used in culinary and cosmetics
 * Jambú oil, is extracted from the flowers, leaves and stem from jambu (Acmella oleracea), contains spilanthol
 * Graviola oil, derived from Annona muricata
 * Tucumã oil, from Astrocaryum aculeatum is used to manufacture soap.
 * Brazil nut oil, culinary and cosmetics use
 * Carapa oil, pharmaceutical use and anti-mosquito candle
 * Buriti oil, from Mauritia flexuosa, used in cosmetics (skin and hair care)
 * Passion fruit oil, derived from Passiflora edulis, has varied applications in cosmetics manufacturing and for uses as a human or animal food.
 * Pracaxi oil, obtained from Pentaclethra macroloba, cosmetics use
 * Solarium oil, derived from chloroplasts, various applications in cooking

Seed oil
Seed oils are vegetable oils obtained from the seed (endosperm) rather than other parts of plants. Most vegetable oils are seed oils. Examples are sunflower, corn, and sesame oils.

Pre-pressing
Oils are extracted first by expeller or cold pressing methods, then solvent expelling the rest of the oils from the leftover matter. This is a method used by larger capacity oil mills. As the energy consumption of the mechanical press increases as more oil is released, it is more efficient to extract the rest of the oil (past around 60%) by solvent extraction.

Used oil
A large quantity of used vegetable oil is produced and recycled, mainly from industrial deep fryers in potato processing plants, snack food factories and fast food restaurants.

Recycled oil has numerous uses, including use as a direct fuel, as well as in the production of biodiesel, livestock feed, pet food, soap, detergent, cosmetics, and industrial chemicals.

Since 2002, an increasing number of European Union countries have prohibited the inclusion of recycled vegetable oil from catering in animal feed. Used cooking oils from food manufacturing, however, as well as fresh or unused cooking oil, continue to be used in their animal feed.

Shelf life
Due to their susceptibility to oxidation from the exposure to oxygen, heat and light, resulting in the formation of oxidation products, such as peroxides and hydroperoxides, plant oils rich in polyunsaturated fatty acids have a limited shelf-life.

Product labeling
In Canada, palm oil is one of five vegetable oils, along with palm kernel oil, coconut oil, peanut oil, and cocoa butter, which must be specifically named in the list of ingredients for a food product. Also, oils in Canadian food products which have been modified or hydrogenated must contain the word "modified" or "hydrogenated" when listed as an ingredient. A mix of oils other than the aforementioned exceptions may simply be listed as "vegetable oil" in Canada; however, if the food product is a cooking oil, salad oil or table oil, the type of oil must be specified and listing "vegetable oil" as an ingredient is not acceptable.

From December 2014, all food products produced in the European Union were legally required to indicate the specific vegetable oil used in their manufacture, following the introduction of the Food Information to Consumers Regulation.

title: Vegetable oil