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Treatment may involve oral administration of dilute calcium hydroxide or calcium chloride to prevent further absorption, and injection of calcium gluconate to increase the calcium levels in the blood. Hydrogen fluoride is more dangerous than salts such as NaF because it is corrosive and volatile, and can result in fata... | Fluoride | Wikipedia | 438 | 155650 | https://en.wikipedia.org/wiki/Fluoride | Physical sciences | Halide salts | Chemistry |
Other derivatives
Organic and inorganic anions are produced from fluoride, including:
Bifluoride, used as an etchant for glass
Tetrafluoroberyllate
Hexafluoroplatinate
Tetrafluoroborate used in organometallic synthesis
Hexafluorophosphate used as an electrolyte in commercial secondary batteries.
Trifluoromethanesulfon... | Fluoride | Wikipedia | 85 | 155650 | https://en.wikipedia.org/wiki/Fluoride | Physical sciences | Halide salts | Chemistry |
Sodium bicarbonate (IUPAC name: sodium hydrogencarbonate), commonly known as baking soda or bicarbonate of soda, is a chemical compound with the formula NaHCO3. It is a salt composed of a sodium cation (Na+) and a bicarbonate anion (HCO3−). Sodium bicarbonate is a white solid that is crystalline but often appears as a ... | Sodium bicarbonate | Wikipedia | 435 | 155725 | https://en.wikipedia.org/wiki/Sodium%20bicarbonate | Physical sciences | Salts | null |
Acidic materials that induce this reaction include hydrogen phosphates, cream of tartar, lemon juice, yogurt, buttermilk, cocoa, and vinegar. Baking soda may be used together with sourdough, which is acidic, making a lighter product with a less acidic taste. Since the reaction occurs slowly at room temperature, mixture... | Sodium bicarbonate | Wikipedia | 508 | 155725 | https://en.wikipedia.org/wiki/Sodium%20bicarbonate | Physical sciences | Salts | null |
Fire extinguisher
Sodium bicarbonate can be used to extinguish small grease or electrical fires by being thrown over the fire, as heating of sodium bicarbonate releases carbon dioxide. However, it should not be applied to fires in deep fryers; the sudden release of gas may cause the grease to splatter. Sodium bicarbona... | Sodium bicarbonate | Wikipedia | 491 | 155725 | https://en.wikipedia.org/wiki/Sodium%20bicarbonate | Physical sciences | Salts | null |
A mixture of sodium bicarbonate and polyethylene glycol such as PegLyte, dissolved in water and taken orally, is an effective gastrointestinal lavage preparation and laxative prior to gastrointestinal surgery, gastroscopy, etc.
Intravenous sodium bicarbonate in an aqueous solution is sometimes used for cases of acidos... | Sodium bicarbonate | Wikipedia | 508 | 155725 | https://en.wikipedia.org/wiki/Sodium%20bicarbonate | Physical sciences | Salts | null |
Antacid (such as baking soda) solutions have been prepared and used by protesters to alleviate the effects of exposure to tear gas during protests.
Similarly to its use in baking, sodium bicarbonate is used together with a mild acid such as tartaric acid as the excipient in effervescent tablets: when such a tablet is ... | Sodium bicarbonate | Wikipedia | 427 | 155725 | https://en.wikipedia.org/wiki/Sodium%20bicarbonate | Physical sciences | Salts | null |
A manufacturer recommends a paste made from baking soda with minimal water as a gentle scouring powder. Such a paste can be useful in removing surface rust because the rust forms a water-soluble compound when in a concentrated alkaline solution. Cold water should be used since hot-water solutions can corrode steel. Sod... | Sodium bicarbonate | Wikipedia | 498 | 155725 | https://en.wikipedia.org/wiki/Sodium%20bicarbonate | Physical sciences | Salts | null |
Sodium bicarbonate is an amphoteric compound. Aqueous solutions are mildly alkaline due to the formation of carbonic acid and hydroxide ion:
HCO + H2O → + OH−
Sodium bicarbonate can sometimes be used as a mild neutralization agent and a safer alternative to strong bases like sodium hydroxide. Reaction of sodium bica... | Sodium bicarbonate | Wikipedia | 471 | 155725 | https://en.wikipedia.org/wiki/Sodium%20bicarbonate | Physical sciences | Salts | null |
History
The word natron has been in use in many languages throughout modern times (in the forms of anatron, natrum and natron) and originated (like Spanish, French and English natron as well as 'sodium') via Arabic naṭrūn (or anatrūn; cf. the Lower Egyptian “Natrontal” Wadi El Natrun, where a mixture of sodium carbonat... | Sodium bicarbonate | Wikipedia | 495 | 155725 | https://en.wikipedia.org/wiki/Sodium%20bicarbonate | Physical sciences | Salts | null |
Production
Sodium bicarbonate is produced industrially from sodium carbonate:
Na2CO3 + CO2 + H2O → 2 NaHCO3
It is produced on the scale of about 100,000 tonnes/year (as of 2001) with a worldwide production capacity of 2.4 million tonnes per year (as of 2002). Commercial quantities of baking soda are also produced... | Sodium bicarbonate | Wikipedia | 370 | 155725 | https://en.wikipedia.org/wiki/Sodium%20bicarbonate | Physical sciences | Salts | null |
Sodium bicarbonate, as "bicarbonate of soda", was a frequent source of punch lines for Groucho Marx in Marx Brothers movies. In Duck Soup, Marx plays the leader of a nation at war. In one scene, he receives a message from the battlefield that his general is reporting a gas attack, and Groucho tells his aide: "Tell him ... | Sodium bicarbonate | Wikipedia | 263 | 155725 | https://en.wikipedia.org/wiki/Sodium%20bicarbonate | Physical sciences | Salts | null |
Sodium carbonate (also known as washing soda, soda ash and soda crystals) is the inorganic compound with the formula and its various hydrates. All forms are white, odourless, water-soluble salts that yield alkaline solutions in water. Historically, it was extracted from the ashes of plants grown in sodium-rich soils, ... | Sodium carbonate | Wikipedia | 496 | 155726 | https://en.wikipedia.org/wiki/Sodium%20carbonate | Physical sciences | Salts | null |
Applications
Some common applications of sodium carbonate include:
As a cleansing agent for domestic purposes like washing clothes. Sodium carbonate is a component of many dry soap powders. It has detergent properties through the process of saponification, which converts fats and grease to water-soluble salts (specifi... | Sodium carbonate | Wikipedia | 358 | 155726 | https://en.wikipedia.org/wiki/Sodium%20carbonate | Physical sciences | Salts | null |
Food additive and cooking
Sodium carbonate has several uses in cuisine, largely because it is a stronger base than baking soda (sodium bicarbonate) but weaker than lye (which may refer to sodium hydroxide or, less commonly, potassium hydroxide). Alkalinity affects gluten production in kneaded doughs, and also improves ... | Sodium carbonate | Wikipedia | 443 | 155726 | https://en.wikipedia.org/wiki/Sodium%20carbonate | Physical sciences | Salts | null |
For example, it is used as a pH regulator to maintain stable alkaline conditions necessary for the action of the majority of photographic film developing agents. It is also a common additive in swimming pools and aquarium water to maintain a desired pH and carbonate hardness (KH). In dyeing with fiber-reactive dyes, so... | Sodium carbonate | Wikipedia | 504 | 155726 | https://en.wikipedia.org/wiki/Sodium%20carbonate | Physical sciences | Salts | null |
Sodium carbonate is soluble in water, and can occur naturally in arid regions, especially in mineral deposits (evaporites) formed when seasonal lakes evaporate. Deposits of the mineral natron have been mined from dry lake bottoms in Egypt since ancient times, when natron was used in the preparation of mummies and in th... | Sodium carbonate | Wikipedia | 401 | 155726 | https://en.wikipedia.org/wiki/Sodium%20carbonate | Physical sciences | Salts | null |
Barilla and kelp
Several "halophyte" (salt-tolerant) plant species and seaweed species can be processed to yield an impure form of sodium carbonate, and these sources predominated in Europe and elsewhere until the early 19th century. The land plants (typically glassworts or saltworts) or the seaweed (typically Fucus sp... | Sodium carbonate | Wikipedia | 503 | 155726 | https://en.wikipedia.org/wiki/Sodium%20carbonate | Physical sciences | Salts | null |
In 1861, the Belgian industrial chemist Ernest Solvay developed a method for making sodium carbonate by first reacting sodium chloride, ammonia, water, and carbon dioxide to generate sodium bicarbonate and ammonium chloride:
The resulting sodium bicarbonate was then converted to sodium carbonate by heating it, releasi... | Sodium carbonate | Wikipedia | 476 | 155726 | https://en.wikipedia.org/wiki/Sodium%20carbonate | Physical sciences | Salts | null |
The Chinese name of Hou's process, lianhe zhijian fa (), means "coupled manufacturing alkali method": Hou's process is coupled to the Haber process and offers better atom economy by eliminating the production of calcium chloride, since any ammonia generated gets used by the reaction. The by-product ammonium chloride ca... | Sodium carbonate | Wikipedia | 80 | 155726 | https://en.wikipedia.org/wiki/Sodium%20carbonate | Physical sciences | Salts | null |
Biological control or biocontrol is a method of controlling pests, whether pest animals such as insects and mites, weeds, or pathogens affecting animals or plants by using other organisms. It relies on predation, parasitism, herbivory, or other natural mechanisms, but typically also involves an active human management ... | Biological pest control | Wikipedia | 273 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
The term "biological control" was first used by Harry Scott Smith at the 1919 meeting of the Pacific Slope Branch of the American Association of Economic Entomologists, in Riverside, California. It was brought into more widespread use by the entomologist Paul H. DeBach (1914–1993) who worked on citrus crop pests throug... | Biological pest control | Wikipedia | 314 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
Biological control techniques as we know them today started to emerge in the 1870s. During this decade, in the US, the Missouri State Entomologist C. V. Riley and the Illinois State Entomologist W. LeBaron began within-state redistribution of parasitoids to control crop pests. The first international shipment of an ins... | Biological pest control | Wikipedia | 470 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
Prickly pear cacti were introduced into Queensland, Australia as ornamental plants, starting in 1788. They quickly spread to cover over 25 million hectares of Australia by 1920, increasing by 1 million hectares per year. Digging, burning, and crushing all proved ineffective. Two control agents were introduced to help c... | Biological pest control | Wikipedia | 476 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
Damage from Hypera postica, the alfalfa weevil, a serious introduced pest of forage, was substantially reduced by the introduction of natural enemies. 20 years after their introduction the population of weevils in the alfalfa area treated for alfalfa weevil in the Northeastern United States remained 75 percent down.
A... | Biological pest control | Wikipedia | 507 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
An example of inoculative release occurs in the horticultural production of several crops in greenhouses. Periodic releases of the parasitoidal wasp, Encarsia formosa, are used to control greenhouse whitefly, while the predatory mite Phytoseiulus persimilis is used for control of the two-spotted spider mite.
The egg p... | Biological pest control | Wikipedia | 421 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
Cropping systems can be modified to favor natural enemies, a practice sometimes referred to as habitat manipulation. Providing a suitable habitat, such as a shelterbelt, hedgerow, or beetle bank where beneficial insects such as parasitoidal wasps can live and reproduce, can help ensure the survival of populations of na... | Biological pest control | Wikipedia | 419 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
Predators are mainly free-living species that directly consume a large number of prey during their whole lifetime. Given that many major crop pests are insects, many of the predators used in biological control are insectivorous species. Lady beetles, and in particular their larvae which are active between May and July ... | Biological pest control | Wikipedia | 452 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
Species used to control spider mites include the predatory mites Phytoseiulus persimilis, Neoseilus californicus, and Amblyseius cucumeris, the predatory midge Feltiella acarisuga, and a ladybird Stethorus punctillum. The bug Orius insidiosus has been successfully used against the two-spotted spider mite and the wester... | Biological pest control | Wikipedia | 372 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
Even amongst arthropods usually thought of as obligate predators of animals (especially other arthropods), floral food sources (nectar and to a lesser degree pollen) are often useful adjunct sources. It had been noticed in one study that adult Adalia bipunctata (predator and common biocontrol of Ephestia kuehniella) co... | Biological pest control | Wikipedia | 503 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
Encarsia formosa is a small parasitoid wasp attacking whiteflies, sap-feeding insects which can cause wilting and black sooty moulds in glasshouse vegetable and ornamental crops. It is most effective when dealing with low level infestations, giving protection over a long period of time. The wasp lays its eggs in young ... | Biological pest control | Wikipedia | 466 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
Bacteria used for biological control infect insects via their digestive tracts, so they offer only limited options for controlling insects with sucking mouth parts such as aphids and scale insects. Bacillus thuringiensis, a soil-dwelling bacterium, is the most widely applied species of bacteria used for biological cont... | Biological pest control | Wikipedia | 422 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
Entomopathogenic fungi, which cause disease in insects, include at least 14 species that attack aphids. Beauveria bassiana is mass-produced and used to manage a wide variety of insect pests including whiteflies, thrips, aphids and weevils. Lecanicillium spp. are deployed against white flies, thrips and aphids. Metarhiz... | Biological pest control | Wikipedia | 489 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
A mammalian virus, the rabbit haemorrhagic disease virus was introduced to Australia to attempt to control the European rabbit populations there. It escaped from quarantine and spread across the country, killing large numbers of rabbits. Very young animals survived, passing immunity to their offspring in due course and... | Biological pest control | Wikipedia | 413 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
In cases of massive and severe infection of invasive pests, techniques of pest control are often used in combination. An example is the emerald ash borer, Agrilus planipennis, an invasive beetle from China, which has destroyed tens of millions of ash trees in its introduced range in North America. As part of the campai... | Biological pest control | Wikipedia | 496 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
Difficulties
Many of the most important pests are exotic, invasive species that severely impact agriculture, horticulture, forestry, and urban environments. They tend to arrive without their co-evolved
parasites, pathogens and predators, and by escaping from these, populations may soar. Importing the natural enemies of... | Biological pest control | Wikipedia | 497 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
Rhinocyllus conicus, a seed-feeding weevil, was introduced to North America to control exotic musk thistle (Carduus nutans) and Canadian thistle (Cirsium arvense). However, the weevil also attacks native thistles, harming such species as the endemic Platte thistle (Cirsium neomexicanum) by selecting larger plants (whic... | Biological pest control | Wikipedia | 376 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
Grower education
A potential obstacle to the adoption of biological pest control measures is that growers may prefer to stay with the familiar use of pesticides. However, pesticides have undesired effects, including the development of resistance among pests, and the destruction of natural enemies; these may in turn ena... | Biological pest control | Wikipedia | 352 | 155739 | https://en.wikipedia.org/wiki/Biological%20pest%20control | Technology | Pest and disease control | null |
Travel is the movement of people between distant geographical locations. Travel can be done by foot, bicycle, automobile, train, boat, bus, airplane, ship or other means, with or without luggage, and can be one way or round trip. Travel can also include relatively short stays between successive movements, as in the cas... | Travel | Wikipedia | 468 | 155747 | https://en.wikipedia.org/wiki/Travel | Technology | Basics_11 | null |
History
Travel dates back to antiquity where wealthy Greeks and Romans would travel for leisure to their summer homes and villas in cities such as Pompeii and Baiae. While early travel tended to be slower, more dangerous, and more dominated by trade and migration, cultural and technological advances over many years ha... | Travel | Wikipedia | 481 | 155747 | https://en.wikipedia.org/wiki/Travel | Technology | Basics_11 | null |
Geographic types
Travel may be local, regional, national (domestic) or international. In some countries, non-local internal travel may require an internal passport, while international travel typically requires a passport and visa. Tours are a common type of travel. Examples of travel tours are expedition cruises, sma... | Travel | Wikipedia | 300 | 155747 | https://en.wikipedia.org/wiki/Travel | Technology | Basics_11 | null |
ATPases (, Adenosine 5'-TriPhosphatase, adenylpyrophosphatase, ATP monophosphatase, triphosphatase, SV40 T-antigen, ATP hydrolase, complex V (mitochondrial electron transport), (Ca2+ + Mg2+)-ATPase, HCO3−-ATPase, adenosine triphosphatase) are a class of enzymes that catalyze the decomposition of ATP into ADP and a free... | ATPase | Wikipedia | 503 | 155750 | https://en.wikipedia.org/wiki/ATPase | Biology and health sciences | Cell processes | Biology |
Protein design has been able to replicate the ATPase function (weakly) without using natural ATPase sequences or structures. Importantly, while all natural ATPases have some beta-sheet structure, the designed "Alternative ATPase" lacks beta sheet structure, demonstrating that this life-essential function is possible w... | ATPase | Wikipedia | 451 | 155750 | https://en.wikipedia.org/wiki/ATPase | Biology and health sciences | Cell processes | Biology |
The bacterial F0F1-ATPase consists of the soluble F1 domain and the transmembrane F0 domain, which is composed of several subunits with varying stoichiometry. There are two subunits, γ, and ε, that form the central stalk and they are linked to F0. F0 contains a c-subunit oligomer in the shape of a ring (c-ring). The α ... | ATPase | Wikipedia | 469 | 155750 | https://en.wikipedia.org/wiki/ATPase | Biology and health sciences | Cell processes | Biology |
Rotary ATPases
F-ATPases (F1FO-ATPases) in mitochondria, chloroplasts and bacterial plasma membranes are the prime producers of ATP, using the proton gradient generated by oxidative phosphorylation (mitochondria) or photosynthesis (chloroplasts).
F-ATPases lacking a delta/OSCP subunit move sodium ions instead. They ar... | ATPase | Wikipedia | 380 | 155750 | https://en.wikipedia.org/wiki/ATPase | Biology and health sciences | Cell processes | Biology |
P-ATPases (sometime known as E1-E2 ATPases) are found in bacteria and also in eukaryotic plasma membranes and organelles. Its name is due to short time attachment of inorganic phosphate at the aspartate residues at the time of activation. Function of P-ATPase is to transport a variety of different compounds, like ions ... | ATPase | Wikipedia | 145 | 155750 | https://en.wikipedia.org/wiki/ATPase | Biology and health sciences | Cell processes | Biology |
Human genes
Na+/K+ transporting: ATP1A1, ATP1A2, ATP1A3, ATP1A4, ATP1B1, ATP1B2, ATP1B3, ATP1B4
Ca++ transporting: ATP2A1, ATP2A2, ATP2A3, ATP2B1, ATP2B2, ATP2B3, ATP2B4, ATP2C1, ATP2C2
Mg++ transporting: ATP3
H+/K+ exchanging: ATP4A
H+ transporting, mitochondrial: ATP5A1, ATP5B, ATP5C1, ATP5C2, ATP5D, ATP5E, ATP5... | ATPase | Wikipedia | 491 | 155750 | https://en.wikipedia.org/wiki/ATPase | Biology and health sciences | Cell processes | Biology |
A gravity assist, gravity assist maneuver, swing-by, or generally a gravitational slingshot in orbital mechanics, is a type of spaceflight flyby which makes use of the relative movement (e.g. orbit around the Sun) and gravity of a planet or other astronomical object to alter the path and speed of a spacecraft, typical... | Gravity assist | Wikipedia | 405 | 155758 | https://en.wikipedia.org/wiki/Gravity%20assist | Physical sciences | Orbital mechanics | null |
Translating this analogy into space: in the planet reference frame, the spaceship has a vertical velocity of v relative to the planet. After the slingshot occurs the spaceship is leaving on a course 90 degrees to that which it arrived on. It will still have a velocity of v, but in the horizontal direction. In the Sun r... | Gravity assist | Wikipedia | 483 | 155758 | https://en.wikipedia.org/wiki/Gravity%20assist | Physical sciences | Orbital mechanics | null |
If more speed is needed than available from gravity assist alone, a rocket burn near the periapsis (closest planetary approach) uses the least fuel. A given rocket burn always provides the same change in velocity (Δv), but the change in kinetic energy is proportional to the vehicle's velocity at the time of the burn. T... | Gravity assist | Wikipedia | 486 | 155758 | https://en.wikipedia.org/wiki/Gravity%20assist | Physical sciences | Orbital mechanics | null |
Although the orbital speed of an inner planet is greater than that of the Earth, a spacecraft traveling to an inner planet, even at the minimum speed needed to reach it, is still accelerated by the Sun's gravity to a speed notably greater than the orbital speed of that destination planet. If the spacecraft's purpose is... | Gravity assist | Wikipedia | 334 | 155758 | https://en.wikipedia.org/wiki/Gravity%20assist | Physical sciences | Orbital mechanics | null |
Because additional fuel is needed to lift fuel into space, space missions are designed with a tight propellant "budget", known as the "delta-v budget". The delta-v budget is in effect the total propellant that will be available after leaving the earth, for speeding up, slowing down, stabilization against external buffe... | Gravity assist | Wikipedia | 495 | 155758 | https://en.wikipedia.org/wiki/Gravity%20assist | Physical sciences | Orbital mechanics | null |
Interplanetary slingshots using the Sun itself are not possible because the Sun is at rest relative to the Solar System as a whole. However, thrusting when near the Sun has the same effect as the powered slingshot described as the Oberth effect. This has the potential to magnify a spacecraft's thrusting power enormousl... | Gravity assist | Wikipedia | 486 | 155758 | https://en.wikipedia.org/wiki/Gravity%20assist | Physical sciences | Orbital mechanics | null |
Mariner 10
The Mariner 10 probe was the first spacecraft to use the gravitational slingshot effect to reach another planet, passing by Venus on 5 February 1974 on its way to becoming the first spacecraft to explore Mercury.
Voyager 1
Voyager 1 was launched by NASA on September 5, 1977. It gained the energy to escape t... | Gravity assist | Wikipedia | 450 | 155758 | https://en.wikipedia.org/wiki/Gravity%20assist | Physical sciences | Orbital mechanics | null |
Cassini
The Cassini–Huygens spacecraft was launched from Earth on 15 October 1997, followed by gravity assist flybys of Venus (26 April 1998 and 21 June 1999), Earth (18 August 1999), and Jupiter (30 December 2000). Transit to Saturn took 6.7 years, the spacecraft arrived at 1 July 2004. Its trajectory was called "the ... | Gravity assist | Wikipedia | 429 | 155758 | https://en.wikipedia.org/wiki/Gravity%20assist | Physical sciences | Orbital mechanics | null |
The Parker Solar Probe, launched by NASA in 2018, has seven planned Venus gravity assists. Each gravity assist brings the Parker Solar Probe progressively closer to the Sun. As of 2022, the spacecraft has performed five of its seven assists. The Parker Solar Probe's mission will make the closest approach to the Sun by ... | Gravity assist | Wikipedia | 504 | 155758 | https://en.wikipedia.org/wiki/Gravity%20assist | Physical sciences | Orbital mechanics | null |
In the novel 2001: A Space Odyssey – but not the movie – Discovery performs such a manoeuvre to gain speed as it goes around Jupiter. As Arthur C. Clarke made clear at various times, the location of TMA-2 was switched from near Saturn (in the novel) to near Jupiter (in the movie). | Gravity assist | Wikipedia | 68 | 155758 | https://en.wikipedia.org/wiki/Gravity%20assist | Physical sciences | Orbital mechanics | null |
In astronautics, the Hohmann transfer orbit () is an orbital maneuver used to transfer a spacecraft between two orbits of different altitudes around a central body. For example, a Hohmann transfer could be used to raise a satellite's orbit from low Earth orbit to geostationary orbit. In the idealized case, the initial ... | Hohmann transfer orbit | Wikipedia | 470 | 155760 | https://en.wikipedia.org/wiki/Hohmann%20transfer%20orbit | Physical sciences | Orbital mechanics | Astronomy |
Example
The diagram shows a Hohmann transfer orbit to bring a spacecraft from a lower circular orbit into a higher one. It is an elliptic orbit that is tangential both to the lower circular orbit the spacecraft is to leave (cyan, labeled 1 on diagram) and the higher circular orbit that it is to reach (red, labeled 3 o... | Hohmann transfer orbit | Wikipedia | 471 | 155760 | https://en.wikipedia.org/wiki/Hohmann%20transfer%20orbit | Physical sciences | Orbital mechanics | Astronomy |
Transfer orbits can go more than 360° around the primary. These multiple-revolution transfers are sometimes referred to as Type III and Type IV, where a Type III is a Type I plus 360°, and a Type IV is a Type II plus 360°.
Uses
A Hohmann transfer orbit can be used to transfer an object's orbit toward another object, ... | Hohmann transfer orbit | Wikipedia | 510 | 155760 | https://en.wikipedia.org/wiki/Hohmann%20transfer%20orbit | Physical sciences | Orbital mechanics | Astronomy |
angular alignment α (in radians) at the time of start between the source object and the target object shall be
Example
Consider a geostationary transfer orbit, beginning at r1 = 6,678 km (altitude 300 km) and ending in a geostationary orbit with r2 = 42,164 km (altitude 35,786 km).
In the smaller circular orbit the... | Hohmann transfer orbit | Wikipedia | 498 | 155760 | https://en.wikipedia.org/wiki/Hohmann%20transfer%20orbit | Physical sciences | Orbital mechanics | Astronomy |
When used to move a spacecraft from orbiting one planet to orbiting another, the Oberth effect allows to use less delta-v than the sum of the delta-v for separate manoeuvres to escape the first planet, followed by a Hohmann transfer to the second planet, followed by insertion into an orbit around the other planet.
For... | Hohmann transfer orbit | Wikipedia | 426 | 155760 | https://en.wikipedia.org/wiki/Hohmann%20transfer%20orbit | Physical sciences | Orbital mechanics | Astronomy |
It is possible to apply the formula given above to calculate the Δv in km/s needed to enter a Hohmann transfer orbit to arrive at various destinations from Earth (assuming circular orbits for the planets). In this table, the column labeled "Δv to enter Hohmann orbit from Earth's orbit" gives the change from Earth's vel... | Hohmann transfer orbit | Wikipedia | 448 | 155760 | https://en.wikipedia.org/wiki/Hohmann%20transfer%20orbit | Physical sciences | Orbital mechanics | Astronomy |
While they require one more engine burn than a Hohmann transfer and generally require a greater travel time, some bi-elliptic transfers require a lower amount of total delta-v than a Hohmann transfer when the ratio of final to initial semi-major axis is 11.94 or greater, depending on the intermediate semi-major axis ch... | Hohmann transfer orbit | Wikipedia | 431 | 155760 | https://en.wikipedia.org/wiki/Hohmann%20transfer%20orbit | Physical sciences | Orbital mechanics | Astronomy |
Transfer orbits using electrical propulsion or low-thrust engines optimize the transfer time to reach the final orbit and not the delta-v as in the Hohmann transfer orbit. For geostationary orbit, the initial orbit is set to be supersynchronous and by thrusting continuously in the direction of the velocity at apogee, t... | Hohmann transfer orbit | Wikipedia | 216 | 155760 | https://en.wikipedia.org/wiki/Hohmann%20transfer%20orbit | Physical sciences | Orbital mechanics | Astronomy |
The sievert (symbol: Sv) is a unit in the International System of Units (SI) intended to represent the stochastic health risk of ionizing radiation, which is defined as the probability of causing radiation-induced cancer and genetic damage. The sievert is important in dosimetry and radiation protection. It is named aft... | Sievert | Wikipedia | 501 | 155823 | https://en.wikipedia.org/wiki/Sievert | Physical sciences | Radioactivity | null |
gray: quantity D—absorbed dose
1 Gy = 1 joule/kilogram—a physical quantity. 1 Gy is the deposit of a joule of radiation energy per kilogram of matter or tissue.
sievert: quantity H—equivalent dose
1 Sv = 1 joule/kilogram—a biological effect. The sievert represents the equivalent biological effect of the deposit of a j... | Sievert | Wikipedia | 410 | 155823 | https://en.wikipedia.org/wiki/Sievert | Physical sciences | Radioactivity | null |
Although the CIPM definition states that the linear energy transfer function (Q) of the ICRU is used in calculating the biological effect, the ICRP in 1990 developed the "protection" dose quantities effective and equivalent dose which are calculated from more complex computational models and are distinguished by not ha... | Sievert | Wikipedia | 408 | 155823 | https://en.wikipedia.org/wiki/Sievert | Physical sciences | Radioactivity | null |
Simple (non-anthropomorphic) "phantoms" are used to relate operational quantities to measured free-air irradiation. The ICRU sphere phantom is based on the definition of an ICRU 4-element tissue-equivalent material which does not really exist and cannot be fabricated. The ICRU sphere is a theoretical 30 cm diameter "ti... | Sievert | Wikipedia | 448 | 155823 | https://en.wikipedia.org/wiki/Sievert | Physical sciences | Radioactivity | null |
Instrument and dosimetry response
This is an actual reading obtained from such as an ambient dose gamma monitor, or a personal dosimeter. Such instruments are calibrated using radiation metrology techniques which will trace them to a national radiation standard, and thereby relate them to an operational quantity. The r... | Sievert | Wikipedia | 474 | 155823 | https://en.wikipedia.org/wiki/Sievert | Physical sciences | Radioactivity | null |
The values of these weighting factors are conservatively chosen to be greater than the bulk of experimental values observed for the most sensitive cell types, based on averages of those obtained for the human population.
Radiation type weighting factor WR
Since different radiation types have different biological effe... | Sievert | Wikipedia | 496 | 155823 | https://en.wikipedia.org/wiki/Sievert | Physical sciences | Radioactivity | null |
The article on effective dose gives the method of calculation. The absorbed dose is first corrected for the radiation type to give the equivalent dose, and then corrected for the tissue receiving the radiation. Some tissues like bone marrow are particularly sensitive to radiation, so they are given a weighting factor t... | Sievert | Wikipedia | 464 | 155823 | https://en.wikipedia.org/wiki/Sievert | Physical sciences | Radioactivity | null |
Proposals for changing the definition of protection dose quantities
In order to simplify the means of calculating operational quantities and assist in the comprehension of radiation dose protection quantities, ICRP Committee 2 & ICRU Report Committee 26 started in 2010 an examination of different means of achieving thi... | Sievert | Wikipedia | 445 | 155823 | https://en.wikipedia.org/wiki/Sievert | Physical sciences | Radioactivity | null |
The ICRP further states "For internal exposure, committed effective doses are generally determined from an assessment of the intakes of radionuclides from bioassay measurements or other quantities (e.g., activity retained in the body or in daily excreta). The radiation dose is determined from the intake using recommend... | Sievert | Wikipedia | 441 | 155823 | https://en.wikipedia.org/wiki/Sievert | Physical sciences | Radioactivity | null |
The deterministic (acute tissue damage) effects that can lead to acute radiation syndrome only occur in the case of acute high doses (≳ 0.1 Gy) and high dose rates (≳ 0.1 Gy/h) and are conventionally not measured using the unit sievert, but use the unit gray (Gy).
A model of deterministic risk would require different w... | Sievert | Wikipedia | 500 | 155823 | https://en.wikipedia.org/wiki/Sievert | Physical sciences | Radioactivity | null |
Dose rate examples
All conversions between hours and years have assumed continuous presence in a steady field, disregarding known fluctuations, intermittent exposure and radioactive decay. Converted values are shown in parentheses. "/a" is "per annum", which means per year. "/h" means "per hour". | Sievert | Wikipedia | 61 | 155823 | https://en.wikipedia.org/wiki/Sievert | Physical sciences | Radioactivity | null |
The curie (symbol Ci) is a non-SI unit of radioactivity originally defined in 1910. According to a notice in Nature at the time, it was to be named in honour of Pierre Curie, but was considered at least by some to be in honour of Marie Curie as well, and is in later literature considered to be named for both.
It was o... | Curie (unit) | Wikipedia | 478 | 155829 | https://en.wikipedia.org/wiki/Curie%20%28unit%29 | Physical sciences | Radioactivity | Basics and measurement |
The typical human body contains roughly 0.1 μCi (14 mg) of naturally occurring potassium-40. A human body containing of carbon (see Composition of the human body) would also have about 24 nanograms or 0.1 μCi of carbon-14. Together, these would result in a total of approximately 0.2 μCi or 7400 decays per second insid... | Curie (unit) | Wikipedia | 309 | 155829 | https://en.wikipedia.org/wiki/Curie%20%28unit%29 | Physical sciences | Radioactivity | Basics and measurement |
The becquerel (; symbol: Bq) is the unit of radioactivity in the International System of Units (SI). One becquerel is defined as an activity of one per second, on average, for aperiodic activity events referred to a radionuclide. For applications relating to human health this is a small quantity, and SI multiples of th... | Becquerel | Wikipedia | 423 | 155835 | https://en.wikipedia.org/wiki/Becquerel | Physical sciences | Radioactivity | null |
Like any SI unit, Bq can be prefixed; commonly used multiples are kBq (kilobecquerel, ), MBq (megabecquerel, , equivalent to 1 rutherford), GBq (gigabecquerel, ), TBq (terabecquerel, ), and PBq (petabecquerel, ). Large prefixes are common for practical uses of the unit.
Examples
For practical applications, 1 Bq is a ... | Becquerel | Wikipedia | 460 | 155835 | https://en.wikipedia.org/wiki/Becquerel | Physical sciences | Radioactivity | null |
The lux (symbol: lx) is the unit of illuminance, or luminous flux per unit area, in the International System of Units (SI). It is equal to one lumen per square metre. In photometry, this is used as a measure of the irradiance, as perceived by the spectrally unequally responding human eye, of light that hits or passes t... | Lux | Wikipedia | 480 | 155869 | https://en.wikipedia.org/wiki/Lux | Physical sciences | Light | null |
The illuminance provided by a light source on a surface perpendicular to the direction to the source is a measure of the strength of that source as perceived from that location. For instance, a star of apparent magnitude 0 provides 2.08 microlux (μlx) at the Earth's surface. A barely perceptible magnitude 6 star provid... | Lux | Wikipedia | 466 | 155869 | https://en.wikipedia.org/wiki/Lux | Physical sciences | Light | null |
The lux is one lumen per square metre (lm/m2), and the corresponding radiometric unit, which measures irradiance, is the watt per square metre (W/m2). There is no single conversion factor between lux and W/m2; there is a different conversion factor for every wavelength, and it is not possible to make a conversion unles... | Lux | Wikipedia | 442 | 155869 | https://en.wikipedia.org/wiki/Lux | Physical sciences | Light | null |
Use in video-camera specifications
Specifications for video cameras such as camcorders and surveillance cameras often include a minimal illuminance level in lux at which the camera will record a satisfactory image. A camera with good low-light capability will have a lower lux rating. Still cameras do not use such a spe... | Lux | Wikipedia | 407 | 155869 | https://en.wikipedia.org/wiki/Lux | Physical sciences | Light | null |
In botany, the radicle is the first part of a seedling (a growing plant embryo) to emerge from the seed during the process of germination. The radicle is the embryonic root of the plant, and grows downward in the soil (the shoot emerges from the plumule). Above the radicle is the embryonic stem or hypocotyl, supporting... | Radicle | Wikipedia | 283 | 156310 | https://en.wikipedia.org/wiki/Radicle | Biology and health sciences | Plant anatomy and morphology: General | Biology |
Corporate farming is the practice of large-scale agriculture on farms owned or greatly influenced by large companies. This includes corporate ownership of farms and the sale of agricultural products, as well as the roles of these companies in influencing agricultural education, research, and public policy through fundi... | Corporate farming | Wikipedia | 493 | 156339 | https://en.wikipedia.org/wiki/Corporate%20farming | Technology | Agriculture, labor and economy | null |
Contract farming
Farming contracts are agreements between a farmer and a buyer that stipulates what the farmer will grow and how much they will grow usually in return for guaranteed purchase of the product or financial support in purchase of inputs (e.g. feed for livestock growers). In most instances of contract farm... | Corporate farming | Wikipedia | 496 | 156339 | https://en.wikipedia.org/wiki/Corporate%20farming | Technology | Agriculture, labor and economy | null |
The 2012 US Census of Agriculture indicates that 5.06 percent of US farms are corporate farms. These include family corporations (4.51 percent) and non-family corporations (0.55 percent). Of the family farm corporations, 98 percent are small corporations, with 10 or fewer stockholders. Of the non-family farm corpora... | Corporate farming | Wikipedia | 341 | 156339 | https://en.wikipedia.org/wiki/Corporate%20farming | Technology | Agriculture, labor and economy | null |
All nine laws have similar content. They all restrict corporate ability to own and operate on farmland. They all outline exceptions for specific types of corporations. Generally, family farm corporations are exempted, although certain conditions may have to be fulfilled for such exemption (e.g. one or more of: shareh... | Corporate farming | Wikipedia | 495 | 156339 | https://en.wikipedia.org/wiki/Corporate%20farming | Technology | Agriculture, labor and economy | null |
Middle East
Some oil-rich middle east countries operate corporate farming including large-scale irrigation of desert lands for cropping, sometimes through partially or fully state-owned companies, especially with regards to water resource management. | Corporate farming | Wikipedia | 42 | 156339 | https://en.wikipedia.org/wiki/Corporate%20farming | Technology | Agriculture, labor and economy | null |
Araucaria araucana, commonly called the monkey puzzle tree, monkey tail tree, piñonero, pewen or pehuen pine, is an evergreen tree growing to a trunk diameter of and a height of . It is native to central and southern Chile and western Argentina. It is the hardiest species in the conifer genus Araucaria. Because of the... | Araucaria araucana | Wikipedia | 331 | 156455 | https://en.wikipedia.org/wiki/Araucaria%20araucana | Biology and health sciences | Pinophyta (Conifers) | Plants |
The tree's native habitat is the lower slopes of the Chilean and Argentine south-central Andes, approximately between and 1,700 m (5,600 ft). In the Chilean Coast Range A. araucana can be found as far south as Villa Las Araucarias (latitude 38°30' S) at an altitude of 640 m asl. Juvenile trees exhibit a broadly pyrami... | Araucaria araucana | Wikipedia | 420 | 156455 | https://en.wikipedia.org/wiki/Araucaria%20araucana | Biology and health sciences | Pinophyta (Conifers) | Plants |
Another major threat to the survival of A. araucana, is the presence of non-native seed eating species, in particular mammals, which have been shown to severely restrict the reproduction of the tree in comparison to native seed eaters. However it is still unclear as to how large a role these invasive species play in th... | Araucaria araucana | Wikipedia | 294 | 156455 | https://en.wikipedia.org/wiki/Araucaria%20araucana | Biology and health sciences | Pinophyta (Conifers) | Plants |
Its seeds (, ) are edible, similar to large pine nuts, and are harvested by indigenous peoples in Argentina and Chile. The tree has some potential to be a food crop in other areas in the future, thriving in climates with cool oceanic summers, e.g., western Scotland, where other nut crops do not grow well. A group of si... | Araucaria araucana | Wikipedia | 464 | 156455 | https://en.wikipedia.org/wiki/Araucaria%20araucana | Biology and health sciences | Pinophyta (Conifers) | Plants |
First identified by Europeans in Chile in the 1780s, it was named Pinus araucana by Molina in 1782. In 1789, de Jussieu erected a new genus called Araucaria based on the species, and in 1797, Pavón published a new description of the species which he called Araucaria imbricata (an illegitimate name, as it did not use Mo... | Araucaria araucana | Wikipedia | 477 | 156455 | https://en.wikipedia.org/wiki/Araucaria%20araucana | Biology and health sciences | Pinophyta (Conifers) | Plants |
The recently found 'Wollemi pine', Wollemia, discovered in southeast Australia, is classed in the plant family Araucariaceae. Their common ancestry dates to a time when Australia, Antarctica, and South America were linked by land – all three continents were once part of the supercontinent known as Gondwana.
Gallery | Araucaria araucana | Wikipedia | 69 | 156455 | https://en.wikipedia.org/wiki/Araucaria%20araucana | Biology and health sciences | Pinophyta (Conifers) | Plants |
The brittle-ductile transition zone (hereafter the "transition zone") is the zone of the Earth's crust that marks the transition from the upper, more brittle crust to the lower, more ductile crust. For quartz and feldspar-rich rocks in continental crust, the transition zone occurs at an approximate depth of 20 km, at t... | Brittle–ductile transition zone | Wikipedia | 424 | 6944639 | https://en.wikipedia.org/wiki/Brittle%E2%80%93ductile%20transition%20zone | Physical sciences | Structural geology | Earth science |
Examples exposed on land
Sections of fault zones once active in the transition zone, and now exposed at the surface, typically have a complex overprinting of brittle and ductile rock types. Cataclasites or pseudotachylite breccias with mylonite clasts are common, as are ductilely deformed cataclasites and pseudotachyl... | Brittle–ductile transition zone | Wikipedia | 156 | 6944639 | https://en.wikipedia.org/wiki/Brittle%E2%80%93ductile%20transition%20zone | Physical sciences | Structural geology | Earth science |
An induction furnace is an electrical furnace in which the heat is applied by induction heating of metal.
Induction furnace capacities range from less than one kilogram to one hundred tons, and are used to melt iron and steel, copper, aluminum, and precious metals.
The advantage of the induction furnace is a clean, ... | Induction furnace | Wikipedia | 496 | 2964983 | https://en.wikipedia.org/wiki/Induction%20furnace | Technology | Metallurgy | null |
Operating frequencies range from utility frequency (50 or 60 Hz) to 400 kHz or higher, usually depending on the material being melted, the capacity (volume) of the furnace and the melting speed required. Generally, the smaller the volume of the melts, the higher the frequency of the furnace used; this is due to the ski... | Induction furnace | Wikipedia | 234 | 2964983 | https://en.wikipedia.org/wiki/Induction%20furnace | Technology | Metallurgy | null |
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