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in colored or white arcs, rings or spots in the sky. Many halos are positioned near the Sun or Moon, but others are elsewhere and even in the opposite part of the sky. They can also form around artificial lights in very cold weather when ice crystals called diamond dust are floating in the nearby air. There are many ty...	{ "page_id": 28779877, "title": "Atmospheric optics" }
the Sun rises higher, the rays passing through the crystals are increasingly skewed from the horizontal plane. Their angle of deviation increases and the sundogs move further from the Sun. However, they always stay at the same elevation as the Sun. Sun dogs are red-colored at the side nearest the Sun. Farther out the c...	{ "page_id": 28779877, "title": "Atmospheric optics" }
from mountains and tall buildings, when there are clouds or fog below the level of the observer, or on days with ground fog. The glory is related to the optical phenomenon anthelion. == Rainbow == A rainbow is a narrow, multicoloured semicircular arc due to dispersion of white light by a multitude of drops of water, us...	{ "page_id": 28779877, "title": "Atmospheric optics" }
noticeably darker that the sky withinthe primary bow and that beyond the secondary bow. It known an Alexander's Dark Band. The reason for this apparent reduction in sky brightness is that, while light from the sky enclosed within the primary bow comes from droplet reflection, and light beyond the secondary bow also com...	{ "page_id": 28779877, "title": "Atmospheric optics" }
inferior images on land are very easily mistaken for the reflections from a small body of water. Mirages can be categorized as "inferior" (meaning lower), "superior" (meaning higher) and "Fata Morgana", one kind of superior mirage consisting of a series of unusually elaborate, vertically stacked images, which form one ...	{ "page_id": 28779877, "title": "Atmospheric optics" }
of superior mirage, which, like many other kinds of superior mirages, is seen in a narrow band right above the horizon. It is an Italian phrase derived from the vulgar Latin for "fairy" and the Arthurian sorcerer Morgan le Fay, from a belief that the mirage, often seen in the Strait of Messina, were fairy castles in th...	{ "page_id": 28779877, "title": "Atmospheric optics" }
made up of flattened hourglass shapes. The mirage requires rays of sunlight to have an inversion layer for hundreds of kilometres, and depends on the inversion layer's temperature gradient. The sunlight must bend to the Earth's curvature at least 400 kilometres (250 mi) to allow an elevation rise of 5 degrees for sight...	{ "page_id": 28779877, "title": "Atmospheric optics" }
horizon. == Atmospheric refraction == Atmospheric refraction influences the apparent position of astronomical and terrestrial objects, usually causing them to appear higher than they actually are. For this reason navigators, astronomers, and surveyors observe positions when these effects are minimal. Sailors will only ...	{ "page_id": 28779877, "title": "Atmospheric optics" }
The following compounds are liquid at room temperature and are completely miscible with water; they are often used as solvents. Many of them are hygroscopic. == Organic compounds == == Inorganic compounds == == See also == Category:Alcohol solvents == External links == Solvent miscibility table [1] Diethylenetriamine [...	{ "page_id": 34350438, "title": "List of water-miscible solvents" }
K. W. Michael Siu is a Canadian chemist, currently a distinguished research professor at York University. He is a Fellow of the Royal Society of Canada and Chemical Institute of Canada. == References ==	{ "page_id": 53028198, "title": "K. W. Michael Siu" }
In physics, specifically electromagnetism, the Biot–Savart law ( or ) is an equation describing the magnetic field generated by a constant electric current. It relates the magnetic field to the magnitude, direction, length, and proximity of the electric current. The Biot–Savart law is fundamental to magnetostatics. It ...	{ "page_id": 75110, "title": "Biot–Savart law" }
element ( d ℓ {\displaystyle d{\boldsymbol {\ell }}} ) at point ℓ {\displaystyle {\boldsymbol {\ell }}} to the point at which the field is being computed ( r {\displaystyle \mathbf {r} } ), and μ0 is the magnetic constant. Alternatively: B ( r ) = μ 0 4 π ∫ C I d ℓ × r ^ ′ \| r ′ \| 2 {\displaystyle \mathbf {B} (\mathbf ...	{ "page_id": 75110, "title": "Biot–Savart law" }
( x 2 + R 2 ) 3 / 2 x ^ , {\displaystyle \mathbf {B} ={\mu _{0}IR^{2} \over 2(x^{2}+R^{2})^{3/2}}{\hat {\mathbf {x} }},} where x ^ {\displaystyle {\hat {\mathbf {x} }}} is the unit vector of along the center-line of the loop (and the loop is taken to be centered at the origin).: Sec 5-2, Eqn (25) Loops such as the one ...	{ "page_id": 75110, "title": "Biot–Savart law" }
{B} (\mathbf {r} )={\frac {\mu _{0}}{4\pi }}I\int _{C}{\frac {d{\boldsymbol {\ell }}\times \mathbf {r'} }{\|\mathbf {r'} \|^{3}}}} i.e., the current can be taken out of the integral. === Point charge at constant velocity === In the case of a point charged particle q moving at a constant velocity v, Maxwell's equations gi...	{ "page_id": 75110, "title": "Biot–Savart law" }
{r} }}' \over \|\mathbf {r} '\|^{2}}} These equations were first derived by Oliver Heaviside in 1888. Some authors call the above equation for B {\displaystyle \mathbf {B} } the "Biot–Savart law for a point charge" due to its close resemblance to the standard Biot–Savart law. However, this language is misleading as the B...	{ "page_id": 75110, "title": "Biot–Savart law" }
By analogy, the magnetic equation is an inductive current involving spin. There is no linear motion in the inductive current along the direction of the B vector. The magnetic inductive current represents lines of force. In particular, it represents lines of inverse square law force. In aerodynamics the induced air curr...	{ "page_id": 75110, "title": "Biot–Savart law" }
(signed) angles between the point and the two ends of the segment. == The Biot–Savart law, Ampère's circuital law, and Gauss's law for magnetism == In a magnetostatic situation, the magnetic field B as calculated from the Biot–Savart law will always satisfy Gauss's law for magnetism and Ampère's circuital law: In a non...	{ "page_id": 75110, "title": "Biot–Savart law" }
ISBN 978-0-8053-9045-2. == Further reading == Electricity and Modern Physics (2nd Edition), G.A.G. Bennet, Edward Arnold (UK), 1974, ISBN 0-7131-2459-8 Essential Principles of Physics, P.M. Whelan, M.J. Hodgeson, 2nd Edition, 1978, John Murray, ISBN 0-7195-3382-1 The Cambridge Handbook of Physics Formulas, G. Woan, Cam...	{ "page_id": 75110, "title": "Biot–Savart law" }
Syed Husain Zaheer was an Indian chemist, politician and the director general of the Council of Scientific and Industrial Research (CSIR), the largest research and development organisation in India. Prior to taking up the directorship of CSIR, He served as the director of the Indian Institute of Chemical Technology, a ...	{ "page_id": 50144617, "title": "Syed Husain Zaheer" }
A medical physicist is a health professional with specialist education and training in the concepts and techniques of applying physics in medicine and competent to practice independently in one or more of the subfields (specialties) of medical physics. A medical physicist plays a fundamental role in applying physics to...	{ "page_id": 2827625, "title": "Medical physicist" }
first degree in Physics or equivalent (e.g., biophysics, electrical or mechanical engineering, computing), a Masters in Medical Physics and a 2-year training Residency. The European Commission has produced 'European Guidelines on the Medical Physics Expert'. ==== Finland ==== In Finland the qualification of medical phy...	{ "page_id": 2827625, "title": "Medical physicist" }
Institute of Physics and Engineering in Medicine (IPEM) and registration as a Clinical Scientist. Prior to 2011 the training route in the United Kingdom was administered in two parts, and this scheme is still used in Scotland and Northern Ireland). Part I involved limited clinical experience and a full-time MSc in medi...	{ "page_id": 2827625, "title": "Medical physicist" }
institution. === Russia === The Association of Medical Physicists in Russia is organized and operates [2]. Teaching of medical physics is carried out at Moscow State University, Moscow Institute of Physics and Technology [3], Kuban State University. The scientific journal "Medical Physics" is published [4]. === Interna...	{ "page_id": 2827625, "title": "Medical physicist" }
This is a glossary for the terminology applied in the foundations of quantum mechanics and quantum metaphysics, collectively called quantum philosophy, a subfield of philosophy of physics. Note that this is a highly debated field, hence different researchers may have different definitions on the terms. == Physics == ==...	{ "page_id": 31597935, "title": "Glossary of quantum philosophy" }
Griffiths Bernard d'Espagnat Carl von Weizsäcker 2000s or later: Bob Coecke Robert Spekkens == See also == time arrow quantum chaos probability interpretations relative frequency approach probability theory as extended logic, decision theory history of quantum mechanics == Further reading == Schlosshauer, Maximilian (2...	{ "page_id": 31597935, "title": "Glossary of quantum philosophy" }
In metallurgy, recovery is a process by which a metal or alloy's deformed grains can reduce their stored energy by the removal or rearrangement of defects in their crystal structure. These defects, primarily dislocations, are introduced by plastic deformation of the material and act to increase the yield strength of a ...	{ "page_id": 4334961, "title": "Recovery (metallurgy)" }
in a form of dynamic equilibrium. == Process == === Deformed structure === A heavily deformed metal contains a huge number of dislocations predominantly caught up in 'tangles' or 'forests'. Dislocation motion is relatively difficult in a metal with a low stacking fault energy and so the dislocation distribution after d...	{ "page_id": 4334961, "title": "Recovery (metallurgy)" }
misoriented boundaries. The situation in highly deformed, polycrystalline materials is naturally more complex. Many dislocations of different Burger's vector can interact to form complex 2-D networks. == Development of substructure == As mentioned above, the deformed structure is often a 3-D cellular structure with wal...	{ "page_id": 4334961, "title": "Recovery (metallurgy)" }
The Illinois Mycological Association or IMA is a group of mushroom enthusiasts, citizen scientists, foragers, and professional mycologists based in the Chicago area. == Overview == Meetings are held monthly, except in some winter months, at the Niles Historical & Cultural Center. Originally meetings were held at the Fi...	{ "page_id": 57025907, "title": "Illinois Mycological Association" }
Extraterrestrial life, or alien life (colloquially, aliens), is life that originates from another world rather than on Earth. No extraterrestrial life has yet been scientifically conclusively detected. Such life might range from simple forms such as prokaryotes to intelligent beings, possibly bringing forth civilizatio...	{ "page_id": 9588, "title": "Extraterrestrial life" }
are often hypothesized to be the origin of life on Earth. Hydrothermal vents, acidic hot springs, and volcanic lakes are examples of life forming under difficult circumstances, provide parallels to the extreme environments on other planets and support the possibility of extraterrestrial life. Since the mid-20th century...	{ "page_id": 9588, "title": "Extraterrestrial life" }
emerged, and the first organic compounds may have formed in the protoplanetary disk of dust grains that would eventually create rocky planets like Earth. Although Earth was in a molten state after its birth and may have burned any organics that fell in it, it would have been more receptive once it cooled down. Once the...	{ "page_id": 9588, "title": "Extraterrestrial life" }
of the Local Group, a galaxy group that is in turn part of the Laniakea Supercluster. The universe is composed of all similar structures in existence. The immense distances between celestial objects is a difficulty for the study of extraterrestrial life. So far, humans have only set foot on the Moon and sent robotic pr...	{ "page_id": 9588, "title": "Extraterrestrial life" }
not have liquid water because of the conditions of its atmosphere. Jovian planets or gas giants are not considered habitable even if they orbit close enough to their stars as hot Jupiters, due to crushing atmospheric pressures. The actual distances for the habitable zones vary according to the type of star, and even th...	{ "page_id": 9588, "title": "Extraterrestrial life" }
its ease of adaptation and may have stricter requirements. A celestial body may not have any life on it, even if it were habitable. == Likelihood of existence == It is unclear if life, and more importantly, intelligent life in the cosmos is ubiquitous or rare. The hypothesis of ubiquitous extraterrestrial life relies o...	{ "page_id": 9588, "title": "Extraterrestrial life" }
extraterrestrial life and that at this point it is just a desired result and not a reasonable scientific explanation for any gathered data. In 1961, astronomer and astrophysicist Frank Drake devised the Drake equation as a way to stimulate scientific dialogue at a meeting on the search for extraterrestrial intelligence...	{ "page_id": 9588, "title": "Extraterrestrial life" }
sciences and are not knowable by their very nature. This does not allow one to make noteworthy conclusions from the equation. Based on observations from the Hubble Space Telescope, there are nearly 2 trillion galaxies in the observable universe. It is estimated that at least ten percent of all Sun-like stars have a sys...	{ "page_id": 9588, "title": "Extraterrestrial life" }
lifeforms from Earth for simplicity, as it is the only one known to exist. The first basic requirement for life is an environment with non-equilibrium thermodynamics, which means that the thermodynamic equilibrium must be broken by a source of energy. The traditional sources of energy in the cosmos are the stars, such ...	{ "page_id": 9588, "title": "Extraterrestrial life" }
replacement for carbon would need to be able to create complex molecules, store information required for evolution, and be freely available in the medium. To create DNA, RNA, or a close analog, such an element should be able to bind its atoms with many others, creating complex and stable molecules. It should be able to...	{ "page_id": 9588, "title": "Extraterrestrial life" }
life, it may still have a radically different biochemistry. Life is generally considered to be a product of natural selection. It has been proposed that to undergo natural selection a living entity must have the capacity to replicate itself, the capacity to avoid damage/decay, and the capacity to acquire and process re...	{ "page_id": 9588, "title": "Extraterrestrial life" }
considers that convergent evolution would lead to kingdoms similar to our plants and animals, and that many features are likely to develop in alien animals as well, such as bilateral symmetry, limbs, digestive systems and heads with sensory organs. Scientists from the University of Oxford analysed it from the perspecti...	{ "page_id": 9588, "title": "Extraterrestrial life" }
life on Earth originated in some extreme environments that seem unlikely to have harbored life at least at one point in Earth's history. Fossil evidence as well as many historical theories backed up by years of research and studies have marked environments like hydrothermal vents or acidic hot springs as some of the fi...	{ "page_id": 9588, "title": "Extraterrestrial life" }
Earth's atmosphere. If there were the necessary elements and ions on these planets, the same carbon fixing, reduced chemical compounds occurring around hydrothermal vents could also occur on these planets' surfaces and possibly result in the origin of extraterrestrial life. == Planetary habitability in the Solar System...	{ "page_id": 9588, "title": "Extraterrestrial life" }
winds removed the atmosphere and the planet became vulnerable to solar radiation. Ancient life-forms may still have left fossilised remains, and microbes may still survive deep underground. As mentioned, the gas giants and ice giants are unlikely to contain life. The most distant solar system bodies, found in the Kuipe...	{ "page_id": 9588, "title": "Extraterrestrial life" }
does have a subsurface water ocean like several other moons. However, it is of such a great depth that it would be very difficult to access it for study. == Scientific search == The science that searches and studies life in the universe, both on Earth and elsewhere, is called astrobiology. With the study of Earth's lif...	{ "page_id": 9588, "title": "Extraterrestrial life" }
with the presence of living microorganisms. Lack of corroborating evidence from other experiments on the same samples suggests that a non-biological reaction is a more likely hypothesis. In February 2005 NASA scientists reported they may have found some evidence of extraterrestrial life on Mars. The two scientists, Car...	{ "page_id": 9588, "title": "Extraterrestrial life" }
suggests that several organic molecules that serve as building blocks of life may be generated within asteroids and comets. In October 2011, scientists reported that cosmic dust contains complex organic compounds ("amorphous organic solids with a mixed aromatic-aliphatic structure") that could be created naturally, and...	{ "page_id": 9588, "title": "Extraterrestrial life" }
technosignatures, effects on the native planet that may not be caused by natural causes. There are three main types of techno-signatures considered: interstellar communications, effects on the atmosphere, and planetary-sized structures such as Dyson spheres. Organizations such as the SETI Institute search the cosmos fo...	{ "page_id": 9588, "title": "Extraterrestrial life" }
it. The Kardashev scale proposes that a civilization may eventually start consuming energy directly from its local star. This would require giant structures built next to it, called Dyson spheres. Those speculative structures would cause an excess infrared radiation, that telescopes may notice. The infrared radiation i...	{ "page_id": 9588, "title": "Extraterrestrial life" }
in the trillions. The nearest known exoplanet is Proxima Centauri b, located 4.2 light-years (1.3 pc) from Earth in the southern constellation of Centaurus. As of March 2014, the least massive exoplanet known is PSR B1257+12 A, which is about twice the mass of the Moon. The most massive planet listed on the NASA Exopla...	{ "page_id": 9588, "title": "Extraterrestrial life" }
the scientific method yet and based their ideas on pure thought and speculation, but they developed precursor ideas to it, such as that explanations had to be discarded if they contradict observable facts. The discussions of those Greek scholars established many of the pillars that would eventually lead to the idea of ...	{ "page_id": 9588, "title": "Extraterrestrial life" }
scriptures of Jainism. There are multiple "worlds" mentioned in Jain scriptures that support human life. These include, among others, Bharat Kshetra, Mahavideh Kshetra, Airavat Kshetra, and Hari kshetra. Medieval Muslim writers like Fakhr al-Din al-Razi and Muhammad al-Baqir supported cosmic pluralism on the basis of t...	{ "page_id": 9588, "title": "Extraterrestrial life" }
of the late Middle Ages there were many known inaccuracies in the geocentric model, but it was kept in use because naked eye observations provided limited data. Nicolaus Copernicus started the Copernican Revolution by proposing that the planets revolve around the sun rather than Earth. His proposal had little acceptanc...	{ "page_id": 9588, "title": "Extraterrestrial life" }
the charges leveled against him by the Venetian Holy Inquisition, which tried and executed him. The heliocentric model was further strengthened by the postulation of the theory of gravity by Sir Isaac Newton. This theory provided the mathematics that explains the motions of all things in the universe, including planeta...	{ "page_id": 9588, "title": "Extraterrestrial life" }
American astronomer Percival Lowell published his book Mars, followed by Mars and its Canals in 1906, proposing that the canals were the work of a long-gone civilisation. Spectroscopic analysis of Mars's atmosphere began in earnest in 1894, when U.S. astronomer William Wallace Campbell showed that neither water nor oxy...	{ "page_id": 9588, "title": "Extraterrestrial life" }
were immediately attributed to Selenites or Martians, and later ones (such as more powerful telescopes) revealed that all such discoveries were natural features. A famous case is the Cydonia region of Mars, first imaged by the Viking 1 orbiter. The low-resolution photos showed a rock formation that resembled a human fa...	{ "page_id": 9588, "title": "Extraterrestrial life" }
that aliens would have visited Earth in antiquity and prehistoric times but people would have failed to understand it by then. Most UFOs or UFO sightings can be readily explained as sightings of Earth-based aircraft (including top-secret aircraft), known astronomical objects or weather phenomenons, or as hoaxes. Lookin...	{ "page_id": 9588, "title": "Extraterrestrial life" }
with tools of growing complexity and reliability. Although no extraterrestrial life has been found and life may still be just a rarity from Earth, there are scientific reasons to suspect that it can exist elsewhere, and technological advances that may detect it if it does. Many scientists are optimistic about the chanc...	{ "page_id": 9588, "title": "Extraterrestrial life" }
Earth for resources. "If aliens visit us, the outcome would be much as when Columbus landed in America, which didn't turn out well for the Native Americans", he said. Jared Diamond had earlier expressed similar concerns. On 20 July 2015, Hawking and Russian billionaire Yuri Milner, along with the SETI Institute, announ...	{ "page_id": 9588, "title": "Extraterrestrial life" }
of the research objectives of the program is the search for extraterrestrial life. It is also one of the objectives of the Chinese Five-hundred-meter Aperture Spherical Telescope (FAST) program. In 2020, Dmitry Rogozin, the head of the Russian space agency, said the search for extraterrestrial life is one of the main g...	{ "page_id": 9588, "title": "Extraterrestrial life" }
such as insects or octopuses. Costuming and special effects feasibility alongside budget considerations forced films and TV series to tone down the fantasy, but these limitations lessened since the 1990s with the advent of computer-generated imagery (CGI), and later on as CGI became more effective and less expensive. R...	{ "page_id": 9588, "title": "Extraterrestrial life" }
Kunstformen der Natur (known in English as Art Forms in Nature) is a book of lithographic and halftone prints by German biologist Ernst Haeckel. == Publication == Originally published in sets of ten between 1899 and 1904 and collectively in two volumes in 1904, it consists of 100 prints of various organisms, many of wh...	{ "page_id": 5318004, "title": "Kunstformen der Natur" }
associated with Art Nouveau were influenced by Haeckel's images, including René Binet, Karl Blossfeldt, Hans Christiansen, and Émile Gallé. One prominent example is the Amsterdam Commodities Exchange designed by Hendrik Petrus Berlage: it was in part inspired by Kunstformen illustrations. == Gallery of prints == Haecke...	{ "page_id": 5318004, "title": "Kunstformen der Natur" }
In chemistry, the dodecahedral molecular geometry describes the shape of compounds where eight atoms or groups of atoms or ligands are arranged around a central atom defining the vertices of a snub disphenoid (also known as a trigonal dodecahedron). This shape has D2d symmetry and is one of the three common shapes for ...	{ "page_id": 58467706, "title": "Dodecahedral molecular geometry" }
In physics, an electronvolt (symbol eV), also written electron-volt and electron volt, is the measure of an amount of kinetic energy gained by a single electron accelerating through an electric potential difference of one volt in vacuum. When used as a unit of energy, the numerical value of 1 eV in joules (symbol J) is...	{ "page_id": 9598, "title": "Electronvolt" }
BeV is therefore equivalent to GeV, though neither is an SI unit. == Relation to other physical properties and units == In the fields of physics in which the electronvolt is used, other quantities are typically measured using units derived from the electronvolt as a product with fundamental constants of importance in t...	{ "page_id": 9598, "title": "Electronvolt" }
describe the particle's momentum in units of eV/c. In natural units in which the fundamental velocity constant c is numerically 1, the c may informally be omitted to express momentum using the unit electronvolt. The energy–momentum relation E 2 = p 2 c 2 + m 0 2 c 4 {\displaystyle E^{2}=p^{2}c^{2}+m_{0}^{2}c^{4}} in na...	{ "page_id": 9598, "title": "Electronvolt" }
dimensionless and equal to unity is widely used: c = ħ = 1. In these units, both distances and times are expressed in inverse energy units (while energy and mass are expressed in the same units, see mass–energy equivalence). In particular, particle scattering lengths are often presented using a unit of inverse particle...	{ "page_id": 9598, "title": "Electronvolt" }
1 e V / k B = 1.602 176 634 × 10 − 19 J 1.380 649 × 10 − 23 J/K = 11 604.518 12 K , {\displaystyle {1\,\mathrm {eV} /k_{\text{B}}}={1.602\ 176\ 634\times 10^{-19}{\text{ J}} \over 1.380\ 649\times 10^{-23}{\text{ J/K}}}=11\ 604.518\ 12{\text{ K}},} where kB is the Boltzmann constant. The kB is assumed when using the el...	{ "page_id": 9598, "title": "Electronvolt" }
the yield of a phototube is measured in phe/keVee (photoelectrons per keV electron-equivalent energy). The relationship between eV, eVr, and eVee depends on the medium the scattering takes place in, and must be established empirically for each material. == Energy comparisons == === Molar energy === One mole of particle...	{ "page_id": 9598, "title": "Electronvolt" }
The self-ionization of water (also autoionization of water, autoprotolysis of water, autodissociation of water, or simply dissociation of water) is an ionization reaction in pure water or in an aqueous solution, in which a water molecule, H2O, deprotonates (loses the nucleus of one of its hydrogen atoms) to become a hy...	{ "page_id": 337279, "title": "Self-ionization of water" }
free in solution, but always attaches itself to a water (or other solvent) molecule to form the hydronium ion H 3 O + {\displaystyle {\ce {H3O+}}} (or other protonated solvent). Later spectroscopic evidence has shown that many protons are actually hydrated by more than one water molecule. The most descriptive notation ...	{ "page_id": 337279, "title": "Self-ionization of water" }
typically very dilute, the activity of water is generally approximated as being equal to unity, which allows the ionic product of water to be expressed as: K e q ≈ a H 3 O + ⋅ a O H − {\displaystyle K_{\rm {eq}}\approx a_{\rm {H_{3}O^{+}}}\cdot a_{\rm {OH^{-}}}} In dilute aqueous solutions, the activities of solutes (d...	{ "page_id": 337279, "title": "Self-ionization of water" }
of the solution density and volume changes (density depending on the water salinity (ionic strength), temperature and pressure); therefore, molality is the preferred unit used in thermodynamic calculations or in precise or less-usual conditions, e.g., for seawater with a density significantly different from that of pur...	{ "page_id": 337279, "title": "Self-ionization of water" }
forming a slightly stronger bond to deuterium because the larger mass of deuterium results in a lower zero-point energy. Expressed with activities a, instead of concentrations, the thermodynamic equilibrium constant for the heavy water ionization reaction is: K e q = a D 3 O + ⋅ a O D − a D 2 O 2 {\displaystyle K_{\rm ...	{ "page_id": 337279, "title": "Self-ionization of water" }
the solvent isolates the two ions, which are stabilized by solvation. Within 1 picosecond, however, a second reorganization of the hydrogen bond network allows rapid proton transfer down the electric potential difference and subsequent recombination of the ions. This timescale is consistent with the time it takes for h...	{ "page_id": 337279, "title": "Self-ionization of water" }
External links == General Chemistry – Autoionization of Water	{ "page_id": 337279, "title": "Self-ionization of water" }
Roger David Kornberg (born April 24, 1947) is an American biochemist and professor of structural biology at Stanford University School of Medicine. Kornberg was awarded the Nobel Prize in Chemistry in 2006 for his studies of the process by which genetic information from DNA is copied to RNA, "the molecular basis of euk...	{ "page_id": 7284095, "title": "Roger D. Kornberg" }
often termed "chromatin" when it is bound to proteins in this manner). Within the nucleosome, Kornberg found that roughly 200 bp of DNA are wrapped around an octamer of histone proteins. With Yahli Lorch, Kornberg showed that a nucleosome on a promoter prevents the initiation of transcription, leading to the recognitio...	{ "page_id": 7284095, "title": "Roger D. Kornberg" }
use X-ray crystallography to solve the 3-dimensional structure of RNA polymerase at atomic resolution. He has recently extended these studies to obtain structural images of RNA polymerase associated with accessory proteins. Through these studies, Kornberg has created an actual picture of how transcription works at a mo...	{ "page_id": 7284095, "title": "Roger D. Kornberg" }
The "Carta di Siracusa on Biodiversity" is a political document agreed at the G8 Environmental Ministers Meeting, held in Syracuse (Sicily) from 22 to 24 April 2009. == Title and organization of the document == The document is organized in a preamble and four sections. The common decision to leave part of the official ...	{ "page_id": 24323457, "title": "Carta di Siracusa on Biodiversity" }
of meetings, July 8, 2009 turn it into a political statement of the heads of state and Governments, and considering it as an essential tool for establishing environmental priorities in global biodiversity. The Italian government is also planning to officially present the document at the United Nations General Assembly ...	{ "page_id": 24323457, "title": "Carta di Siracusa on Biodiversity" }
Electrochemistry is the branch of physical chemistry concerned with the relationship between electrical potential difference and identifiable chemical change. These reactions involve electrons moving via an electronically conducting phase (typically an external electrical circuit, but not necessarily, as in electroless...	{ "page_id": 9601, "title": "Electrochemistry" }
unlike charges attract. Du Fay announced that electricity consisted of two fluids: "vitreous" (from the Latin for "glass"), or positive, electricity; and "resinous," or negative, electricity. This was the two-fluid theory of electricity, which was to be opposed by Benjamin Franklin's one-fluid theory later in the centu...	{ "page_id": 9601, "title": "Electrochemistry" }
and Johann Wilhelm Ritter succeeded in decomposing water into hydrogen and oxygen by electrolysis using Volta's battery. Soon thereafter Ritter discovered the process of electroplating. He also observed that the amount of metal deposited and the amount of oxygen produced during an electrolytic process depended on the d...	{ "page_id": 9601, "title": "Electrochemistry" }
would produce a higher voltage. William Grove produced the first fuel cell in 1839. In 1846, Wilhelm Weber developed the electrodynamometer. In 1868, Georges Leclanché patented a new cell which eventually became the forerunner to the world's first widely used battery, the zinc–carbon cell. Svante Arrhenius published hi...	{ "page_id": 9601, "title": "Electrochemistry" }
evaporated, with oil droplets. Within one day Fletcher measured the charge of an electron within several decimal places. In 1923, Johannes Nicolaus Brønsted and Martin Lowry published essentially the same theory about how acids and bases behave, using an electrochemical basis. In 1937, Arne Tiselius developed the first...	{ "page_id": 9601, "title": "Electrochemistry" }
called oxidation, and the gain of electrons is reduction. This can be easily remembered through the use of mnemonic devices. Two of the most popular are "OIL RIG" (Oxidation Is Loss, Reduction Is Gain) and "LEO" the lion says "GER" (Lose Electrons: Oxidation, Gain Electrons: Reduction). Oxidation and reduction always o...	{ "page_id": 9601, "title": "Electrochemistry" }
Electrochemical reactions in water are better analyzed by using the ion-electron method, where H+, OH− ion, H2O and electrons (to compensate the oxidation changes) are added to the cell's half-reactions for oxidation and reduction. ==== Acidic medium ==== In acidic medium, H+ ions and water are added to balance each ha...	{ "page_id": 9601, "title": "Electrochemistry" }
+ 3 Na2SO3 + H2O → 2 MnO2 + 3 Na2SO4 + 2 KOH ==== Neutral medium ==== The same procedure as used in acidic medium can be applied, for example, to balance the complete combustion of propane: Unbalanced reaction: C3H8 + O2 → CO2 + H2O Reduction: 4 H+ + O2 + 4 e− → 2 H2O Oxidation: 6 H2O + C3H8 → 3 CO2 + 20 e− + 20 H+ By ...	{ "page_id": 9601, "title": "Electrochemistry" }
0 (in the solid form) to a positive oxidation state and become an ion. At the cathode, the metal ion in solution will accept one or more electrons from the cathode and the ion's oxidation state is reduced to 0. This forms a solid metal that electrodeposits on the cathode. The two electrodes must be electrically connect...	{ "page_id": 9601, "title": "Electrochemistry" }
the two electrolytes, the liquid junction can be provided through a porous plug that allows ion flow while minimizing electrolyte mixing. To further minimize mixing of the electrolytes, a salt bridge can be used which consists of an electrolyte saturated gel in an inverted U-tube. As the negatively charged electrons fl...	{ "page_id": 9601, "title": "Electrochemistry" }
combination. The term standard in SHE requires a supply of hydrogen gas bubbled through the electrolyte at a pressure of 1 atm and an acidic electrolyte with H+ activity equal to 1 (usually assumed to be [H+] = 1 mol/liter, i.e. pH = 0). The SHE electrode can be connected to any other electrode by a salt bridge and an ...	{ "page_id": 9601, "title": "Electrochemistry" }
= E°red (cathode) – E°red (anode) = E°red (cathode) + E°oxi (anode) For example, the standard electrode potential for a copper electrode is: Cell diagram Pt(s) \| H2 (1 atm) \| H+ (1 M) \|\| Cu2+ (1 M) \| Cu(s) E°cell = E°red (cathode) – E°red (anode) At standard temperature, pressure and concentration conditions, the cell'...	{ "page_id": 9601, "title": "Electrochemistry" }
the system. Since the free energy is the maximum amount of work that can be extracted from a system, one can write: Δ G = − n e F E c e l l {\displaystyle \Delta G=-n_{e}FE_{\mathrm {cell} }} A positive cell potential gives a negative change in Gibbs free energy. This is consistent with the cell production of an electr...	{ "page_id": 9601, "title": "Electrochemistry" }
}={\frac {0.05916\,\mathrm {V} }{n}}\log K} == Cell EMF dependency on changes in concentration == === Nernst equation === The standard potential of an electrochemical cell requires standard conditions (ΔG°) for all of the reactants. When reactant concentrations differ from standard conditions, the cell potential will d...	{ "page_id": 9601, "title": "Electrochemistry" }
of charge transferred to arrive at a new equation which now bears his name: Δ E = Δ E ∘ − R T n F ln ⁡ Q {\displaystyle \Delta E=\Delta E^{\circ }-{\frac {RT}{nF}}\ln Q} Assuming standard conditions (T = 298 K or 25 °C) and R = 8.3145 J/(K·mol), the equation above can be expressed on base-10 logarithm as shown below: Δ...	{ "page_id": 9601, "title": "Electrochemistry" }
cell reactions for oxidation and reduction are: Oxidation: Cu(s) → Cu2+ (0.05 M) + 2 e− Reduction: Cu2+ (2.0 M) + 2 e− → Cu(s) Overall reaction: Cu2+ (2.0 M) → Cu2+ (0.05 M) The cell's emf is calculated through the Nernst equation as follows: E = E ∘ − 0.05916 V 2 log ⁡ [ C u 2 + ] d i l u t e d [ C u 2 + ] c o n c e n...	{ "page_id": 9601, "title": "Electrochemistry" }
The mercury battery using zinc and mercuric oxide provided higher levels of power and capacity than the original dry cell for early electronic devices, but has been phased out of common use due to the danger of mercury pollution from discarded cells. The lead–acid battery was the first practical secondary (rechargeable...	{ "page_id": 9601, "title": "Electrochemistry" }
electrochemical process, which reveals itself as rust or tarnish on metals like iron or copper and their respective alloys, steel and brass. === Iron corrosion === For iron rust to occur the metal has to be in contact with oxygen and water. The chemical reactions for this process are relatively complex and not all of t...	{ "page_id": 9601, "title": "Electrochemistry" }

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