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Benzoate esters are the product of the acid catalysed reaction with alcohols.
Benzoic acid amides are usually prepared from benzoyl chloride.
Dehydration to benzoic anhydride is induced with acetic anhydride or phosphorus pentoxide.
Highly reactive acid derivatives such as acid halides are easily obtained by mixing ... | Benzoic acid | Wikipedia | 389 | 4106 | https://en.wikipedia.org/wiki/Benzoic%20acid | Physical sciences | Specific acids | Chemistry |
In statistical mechanics and mathematics, a Boltzmann distribution (also called Gibbs distribution) is a probability distribution or probability measure that gives the probability that a system will be in a certain state as a function of that state's energy and the temperature of the system. The distribution is express... | Boltzmann distribution | Wikipedia | 452 | 4107 | https://en.wikipedia.org/wiki/Boltzmann%20distribution | Physical sciences | Statistical mechanics | Physics |
where:
is the exponential function,
is the probability of state ,
is the energy of state ,
is the Boltzmann constant,
is the absolute temperature of the system,
is the number of all states accessible to the system of interest,
(denoted by some authors by ) is the normalization denominator, which is the canoni... | Boltzmann distribution | Wikipedia | 503 | 4107 | https://en.wikipedia.org/wiki/Boltzmann%20distribution | Physical sciences | Statistical mechanics | Physics |
This equation is of great importance to spectroscopy. In spectroscopy we observe a spectral line of atoms or molecules undergoing transitions from one state to another. In order for this to be possible, there must be some particles in the first state to undergo the transition. We may find that this condition is fulfill... | Boltzmann distribution | Wikipedia | 394 | 4107 | https://en.wikipedia.org/wiki/Boltzmann%20distribution | Physical sciences | Statistical mechanics | Physics |
Canonical ensemble (general case)
The canonical ensemble gives the probabilities of the various possible states of a closed system of fixed volume, in thermal equilibrium with a heat bath. The canonical ensemble has a state probability distribution with the Boltzmann form.
Statistical frequencies of subsystems' state... | Boltzmann distribution | Wikipedia | 276 | 4107 | https://en.wikipedia.org/wiki/Boltzmann%20distribution | Physical sciences | Statistical mechanics | Physics |
Although these cases have strong similarities, it is helpful to distinguish them as they generalize in different ways when the crucial assumptions are changed:
When a system is in thermodynamic equilibrium with respect to both energy exchange and particle exchange, the requirement of fixed composition is relaxed and a... | Boltzmann distribution | Wikipedia | 498 | 4107 | https://en.wikipedia.org/wiki/Boltzmann%20distribution | Physical sciences | Statistical mechanics | Physics |
Bioleaching is the extraction or liberation of metals from their ores through the use of living organisms. Bioleaching is one of several applications within biohydrometallurgy and several methods are used to treat ores or concentrates containing copper, zinc, lead, arsenic, antimony, nickel, molybdenum, gold, silver, ... | Bioleaching | Wikipedia | 503 | 4111 | https://en.wikipedia.org/wiki/Bioleaching | Technology | Biotechnology | null |
The ferric ion produced in reaction (2) oxidized more sulfide as in reaction (1), closing the cycle and given the net reaction:
(4)
The net products of the reaction are soluble ferrous sulfate and sulfuric acid.
The microbial oxidation process occurs at the cell membrane of the bacteria. The electrons pass into the... | Bioleaching | Wikipedia | 477 | 4111 | https://en.wikipedia.org/wiki/Bioleaching | Technology | Biotechnology | null |
Further processing
The dissolved copper (Cu2+) ions are removed from the solution by ligand exchange solvent extraction, which leaves other ions in the solution. The copper is removed by bonding to a ligand, which is a large molecule consisting of a number of smaller groups, each possessing a lone electron pair. The l... | Bioleaching | Wikipedia | 395 | 4111 | https://en.wikipedia.org/wiki/Bioleaching | Technology | Biotechnology | null |
With fungi
Several species of fungi can be used for bioleaching. Fungi can be grown on many different substrates, such as electronic scrap, catalytic converters, and fly ash from municipal waste incineration. Experiments have shown that two fungal strains (Aspergillus niger, Penicillium simplicissimum) were able to mob... | Bioleaching | Wikipedia | 455 | 4111 | https://en.wikipedia.org/wiki/Bioleaching | Technology | Biotechnology | null |
Environmental impact
The process is more environmentally friendly than traditional extraction methods. For the company this can translate into profit, since the necessary limiting of sulfur dioxide emissions during smelting is expensive. Less landscape damage occurs, since the bacteria involved grow naturally, and th... | Bioleaching | Wikipedia | 236 | 4111 | https://en.wikipedia.org/wiki/Bioleaching | Technology | Biotechnology | null |
The boiling point of a substance is the temperature at which the vapor pressure of a liquid equals the pressure surrounding the liquid and the liquid changes into a vapor.
The boiling point of a liquid varies depending upon the surrounding environmental pressure. A liquid in a partial vacuum, i.e., under a lower pres... | Boiling point | Wikipedia | 503 | 4115 | https://en.wikipedia.org/wiki/Boiling%20point | Physical sciences | Phase transitions | Physics |
The boiling point corresponds to the temperature at which the vapor pressure of the liquid equals the surrounding environmental pressure. Thus, the boiling point is dependent on the pressure. Boiling points may be published with respect to the NIST, USA standard pressure of 101.325 kPa (1 atm), or the IUPAC standard pr... | Boiling point | Wikipedia | 382 | 4115 | https://en.wikipedia.org/wiki/Boiling%20point | Physical sciences | Phase transitions | Physics |
There are two conventions regarding the standard boiling point of water: The normal boiling point is commonly given as (actually following the thermodynamic definition of the Celsius scale based on the kelvin) at a pressure of 1 atm (101.325 kPa). The IUPAC-recommended standard boiling point of water at a standard pr... | Boiling point | Wikipedia | 324 | 4115 | https://en.wikipedia.org/wiki/Boiling%20point | Physical sciences | Phase transitions | Physics |
The Big Bang is a physical theory that describes how the universe expanded from an initial state of high density and temperature. The notion of an expanding universe was first scientifically originated by physicist Alexander Friedmann in 1922 with the mathematical derivation of the Friedmann equations. The earliest emp... | Big Bang | Wikipedia | 421 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
There remain aspects of the observed universe that are not yet adequately explained by the Big Bang models. After its initial expansion, the universe cooled sufficiently to allow the formation of subatomic particles, and later atoms. The unequal abundances of matter and antimatter that allowed this to occur is an unex... | Big Bang | Wikipedia | 508 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
An important feature of the Big Bang spacetime is the presence of particle horizons. Since the universe has a finite age, and light travels at a finite speed, there may be events in the past whose light has not yet had time to reach earth. This places a limit or a past horizon on the most distant objects that can be ob... | Big Bang | Wikipedia | 511 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
This primordial singularity is itself sometimes called "the Big Bang", but the term can also refer to a more generic early hot, dense phase of the universe. In either case, "the Big Bang" as an event is also colloquially referred to as the "birth" of our universe since it represents the point in history where the unive... | Big Bang | Wikipedia | 459 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
At approximately 10−37 seconds into the expansion, a phase transition caused a cosmic inflation, during which the universe grew exponentially, unconstrained by the light speed invariance, and temperatures dropped by a factor of 100,000. This concept is motivated by the flatness problem, where the density of matter and ... | Big Bang | Wikipedia | 421 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
After about 10−11 seconds, the picture becomes less speculative, since particle energies drop to values that can be attained in particle accelerators. At about 10−6 seconds, quarks and gluons combined to form baryons such as protons and neutrons. The small excess of quarks over antiquarks led to a small excess of baryo... | Big Bang | Wikipedia | 359 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
After the recombination epoch, the slightly denser regions of the uniformly distributed matter gravitationally attracted nearby matter and thus grew even denser, forming gas clouds, stars, galaxies, and the other astronomical structures observable today. The details of this process depend on the amount and type of matt... | Big Bang | Wikipedia | 474 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
All of this cosmic evolution after the inflationary epoch can be rigorously described and modeled by the lambda-CDM model of cosmology, which uses the independent frameworks of quantum mechanics and general relativity. There are no easily testable models that would describe the situation prior to approximately 10−15 se... | Big Bang | Wikipedia | 496 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
In 1924, American astronomer Edwin Hubble's measurement of the great distance to the nearest spiral nebulae showed that these systems were indeed other galaxies. Starting that same year, Hubble painstakingly developed a series of distance indicators, the forerunner of the cosmic distance ladder, using the Hooker teles... | Big Bang | Wikipedia | 443 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
After World War II, two distinct possibilities emerged. One was Fred Hoyle's steady-state model, whereby new matter would be created as the universe seemed to expand. In this model the universe is roughly the same at any point in time. The other was Lemaître's Big Bang theory, advocated and developed by George Gamow, w... | Big Bang | Wikipedia | 457 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
Significant progress in Big Bang cosmology has been made since the late 1990s as a result of advances in telescope technology as well as the analysis of data from satellites such as the Cosmic Background Explorer (COBE), the Hubble Space Telescope and WMAP. Cosmologists now have fairly precise and accurate measurements... | Big Bang | Wikipedia | 495 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
where
is the recessional velocity of the galaxy or other distant object,
is the proper distance to the object, and
is Hubble's constant, measured to be km/s/Mpc by the WMAP.
Hubble's law implies that the universe is uniformly expanding everywhere. This cosmic expansion was predicted from general relativity by F... | Big Bang | Wikipedia | 440 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
The surface of last scattering corresponding to emission of the CMB occurs shortly after recombination, the epoch when neutral hydrogen becomes stable. Prior to this, the universe comprised a hot dense photon-baryon plasma sea where photons were quickly scattered from free charged particles. Peaking at around , the mea... | Big Bang | Wikipedia | 377 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
Using Big Bang models, it is possible to calculate the expected concentration of the isotopes helium-4 (4He), helium-3 (3He), deuterium (2H), and lithium-7 (7Li) in the universe as ratios to the amount of ordinary hydrogen. The relative abundances depend on a single parameter, the ratio of photons to baryons. This valu... | Big Bang | Wikipedia | 430 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
Populations of stars have been aging and evolving, so that distant galaxies (which are observed as they were in the early universe) appear very different from nearby galaxies (observed in a more recent state). Moreover, galaxies that formed relatively recently appear markedly different from galaxies formed at similar d... | Big Bang | Wikipedia | 500 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
Future observations
Future gravitational-wave observatories might be able to detect primordial gravitational waves, relics of the early universe, up to less than a second after the Big Bang.
Problems and related issues in physics
As with any theory, a number of mysteries and problems have arisen as a result of the de... | Big Bang | Wikipedia | 436 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
Dark energy, though speculative, solves numerous problems. Measurements of the cosmic microwave background indicate that the universe is very nearly spatially flat, and therefore according to general relativity the universe must have almost exactly the critical density of mass/energy. But the mass density of the univer... | Big Bang | Wikipedia | 402 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
During the 1970s and the 1980s, various observations showed that there is not sufficient visible matter in the universe to account for the apparent strength of gravitational forces within and between galaxies. This led to the idea that up to 90% of the matter in the universe is dark matter that does not emit light or i... | Big Bang | Wikipedia | 412 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
A resolution to this apparent inconsistency is offered by inflation theory in which a homogeneous and isotropic scalar energy field dominates the universe at some very early period (before baryogenesis). During inflation, the universe undergoes exponential expansion, and the particle horizon expands much more rapidly t... | Big Bang | Wikipedia | 456 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
The problem is that any small departure from the critical density grows with time, and yet the universe today remains very close to flat. Given that a natural timescale for departure from flatness might be the Planck time, 10−43 seconds, the fact that the universe has reached neither a heat death nor a Big Crunch after... | Big Bang | Wikipedia | 466 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
Implications
Given current understanding, scientific extrapolations about the future of the universe are only possible for finite durations, albeit for much longer periods than the current age of the universe. Anything beyond that becomes increasingly speculative. Likewise, at present, a proper understanding of the or... | Big Bang | Wikipedia | 431 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
Some speculative proposals in this regard, each of which entails untested hypotheses, are:
The simplest models, in which the Big Bang was caused by quantum fluctuations. That scenario had very little chance of happening, but, according to the totalitarian principle, even the most improbable event will eventually happe... | Big Bang | Wikipedia | 426 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
Alternatively, if the density in the universe were equal to or below the critical density, the expansion would slow down but never stop. Star formation would cease with the consumption of interstellar gas in each galaxy; stars would burn out, leaving white dwarfs, neutron stars, and black holes. Collisions between thes... | Big Bang | Wikipedia | 374 | 4116 | https://en.wikipedia.org/wiki/Big%20Bang | Physical sciences | Astronomy | null |
A bus (contracted from omnibus, with variants multibus, motorbus, autobus, etc.) is a motor vehicle that carries significantly more passengers than an average car or van, but fewer than the average rail transport. It is most commonly used in public transport, but is also in use for charter purposes, or through private ... | Bus | Wikipedia | 345 | 4146 | https://en.wikipedia.org/wiki/Bus | Technology | Road transport | null |
The word bus is a shortened form of the Latin adjectival form ("for all"), the dative plural of ("all"). The theoretical full name is in French ("vehicle for all"). The name originates from a mass-transport service started in 1823 by a French corn-mill owner named in Richebourg, a suburb of Nantes. A by-product of ... | Bus | Wikipedia | 501 | 4146 | https://en.wikipedia.org/wiki/Bus | Technology | Road transport | null |
In parallel to the development of the bus was the invention of the electric trolleybus, typically fed through trolley poles by overhead wires. The Siemens brothers, William in England and Ernst Werner in Germany, collaborated on the development of the trolleybus concept. Sir William first proposed the idea in an articl... | Bus | Wikipedia | 497 | 4146 | https://en.wikipedia.org/wiki/Bus | Technology | Road transport | null |
The first mass-produced bus model was the B-type double-decker bus, designed by Frank Searle and operated by the London General Omnibus Company—it entered service in 1910, and almost 3,000 had been built by the end of the decade. Hundreds of them saw military service on the Western Front during the First World War.
Th... | Bus | Wikipedia | 484 | 4146 | https://en.wikipedia.org/wiki/Bus | Technology | Road transport | null |
Bus manufacturing may be by a single company (an integral manufacturer), or by one manufacturer's building a bus body over a chassis produced by another manufacturer.
Design
Accessibility
Transit buses used to be mainly high-floor vehicles. However, they are now increasingly of low-floor design and optionally also ... | Bus | Wikipedia | 497 | 4146 | https://en.wikipedia.org/wiki/Bus | Technology | Road transport | null |
Propulsion
The most common power source since the 1920s has been the diesel engine. Early buses, known as trolleybuses, were powered by electricity supplied from overhead lines. Nowadays, electric buses often carry their own battery, which is sometimes recharged on stops/stations to keep the size of the battery small/l... | Bus | Wikipedia | 501 | 4146 | https://en.wikipedia.org/wiki/Bus | Technology | Road transport | null |
Buses and coach services often operate to a predetermined published public transport timetable defining the route and the timing, but smaller vehicles may be used on more flexible demand responsive transport services.
Tourism
Buses play a major part in the tourism industry. Tour buses around the world allow tourists ... | Bus | Wikipedia | 446 | 4146 | https://en.wikipedia.org/wiki/Bus | Technology | Road transport | null |
In many tourist or travel destinations, a bus is part of the tourist attraction, such as the North American tourist trolleys, London's AEC Routemaster heritage routes, or the customised buses of Malta, Asia, and the Americas. Another example of tourist stops is the homes of celebrities, such as tours based near Hollywo... | Bus | Wikipedia | 323 | 4146 | https://en.wikipedia.org/wiki/Bus | Technology | Road transport | null |
Charter bus operators may be completely independent businesses, or charter hire may be a subsidiary business of a public transport operator that might maintain a separate fleet or use surplus buses, coaches, and dual-purpose coach-seated buses. Many private taxicab companies also operate larger minibus vehicles to cate... | Bus | Wikipedia | 398 | 4146 | https://en.wikipedia.org/wiki/Bus | Technology | Road transport | null |
Many organisations, including the police, not for profit, social or charitable groups with a regular need for group transport may find it practical or cost-effective to own and operate a bus for their own needs. These are often minibuses for practical, tax and driver licensing reasons, although they can also be full-si... | Bus | Wikipedia | 370 | 4146 | https://en.wikipedia.org/wiki/Bus | Technology | Road transport | null |
Bus advertising takes many forms, often as interior and exterior adverts and all-over advertising liveries. The practice often extends into the exclusive private hire and use of a bus to promote a brand or product, appearing at large public events, or touring busy streets. The bus is sometimes staffed by promotions per... | Bus | Wikipedia | 476 | 4146 | https://en.wikipedia.org/wiki/Bus | Technology | Road transport | null |
The buses to be found in countries around the world often reflect the quality of the local road network, with high-floor resilient truck-based designs prevalent in several less developed countries where buses are subject to tough operating conditions. Population density also has a major impact, where dense urbanisation... | Bus | Wikipedia | 506 | 4146 | https://en.wikipedia.org/wiki/Bus | Technology | Road transport | null |
Some organisations adapt and operate playbuses or learning buses to provide a playground or learning environments to children who might not have access to proper play areas. An ex-London AEC Routemaster bus has been converted to a mobile theatre and catwalk fashion show.
Some buses meet a destructive end by being ente... | Bus | Wikipedia | 346 | 4146 | https://en.wikipedia.org/wiki/Bus | Technology | Road transport | null |
A utility knife is any type of knife used for general manual work purposes. Such knives were originally fixed-blade knives with durable cutting edges suitable for rough work such as cutting cordage, cutting/scraping hides, butchering animals, cleaning fish scales, reshaping timber, and other tasks. Craft knives are sm... | Utility knife | Wikipedia | 400 | 4168 | https://en.wikipedia.org/wiki/Utility%20knife | Technology | Knives | null |
The fixed or folding blade utility knife is popular for both indoor and outdoor use. One of the most popular types of workplace utility knife is the retractable or folding utility knife (also known as a Stanley knife, box cutter, or by various other names). These types of utility knives are designed as multi-purpose ... | Utility knife | Wikipedia | 509 | 4168 | https://en.wikipedia.org/wiki/Utility%20knife | Technology | Knives | null |
Large fixed-blade utility knives are most often employed in an outdoors context, such as fishing, camping, or hunting. Outdoor utility knives typically feature sturdy blades from in length, with edge geometry designed to resist chipping and breakage.
The term "utility knife" may also refer to small fixed-blade knive... | Utility knife | Wikipedia | 320 | 4168 | https://en.wikipedia.org/wiki/Utility%20knife | Technology | Knives | null |
Another style is a snap-off utility knife that contains a long, segmented blade that slides out from it. As the endmost edge becomes dull, it can be broken off the remaining blade, exposing the next section, which is sharp and ready for use. The snapping is best accomplished with a blade snapper that is often built-in,... | Utility knife | Wikipedia | 361 | 4168 | https://en.wikipedia.org/wiki/Utility%20knife | Technology | Knives | null |
Most utility knives are not well suited to use as offensive weapons, with the exception of some outdoor-type utility knives employing longer blades. However, even small blade type utility knives may sometimes find use as slashing weapons. The 9/11 Commission report stated passengers in cell phone calls reported knives... | Utility knife | Wikipedia | 266 | 4168 | https://en.wikipedia.org/wiki/Utility%20knife | Technology | Knives | null |
Bronze is an alloy consisting primarily of copper, commonly with about 12–12.5% tin and often with the addition of other metals (including aluminium, manganese, nickel, or zinc) and sometimes non-metals (such as phosphorus) or metalloids (such as arsenic or silicon). These additions produce a range of alloys some of wh... | Bronze | Wikipedia | 481 | 4169 | https://en.wikipedia.org/wiki/Bronze | Physical sciences | Chemistry | null |
The earliest known arsenic-copper-alloy artifacts come from a Yahya Culture (Period V 3800-3400 BCE) site, at Tal-i-Iblis on the Iranian plateau, and were smelted from native arsenical copper and copper-arsenides, such as algodonite and domeykite.
The earliest tin-copper-alloy artifact has been dated to , in a Vinča c... | Bronze | Wikipedia | 438 | 4169 | https://en.wikipedia.org/wiki/Bronze | Physical sciences | Chemistry | null |
Transition to iron
Though bronze, whose Vickers hardness is 60–258, is generally harder than wrought iron, with a hardness of 30–80,, the Bronze Age gave way to the Iron Age after a serious disruption of the tin trade: the population migrations of around 1200–1100 BCE reduced the shipment of tin around the Mediterrane... | Bronze | Wikipedia | 429 | 4169 | https://en.wikipedia.org/wiki/Bronze | Physical sciences | Chemistry | null |
Modern commercial bronze (90% copper and 10% zinc) and architectural bronze (57% copper, 3% lead, 40% zinc) are more properly regarded as brass alloys because they contain zinc as the main alloying ingredient. They are commonly used in architectural applications. Plastic bronze contains a significant quantity of lead, ... | Bronze | Wikipedia | 467 | 4169 | https://en.wikipedia.org/wiki/Bronze | Physical sciences | Chemistry | null |
Bronze, or bronze-like alloys and mixtures, were used for coins over a longer period. Bronze was especially suitable for use in boat and ship fittings prior to the wide employment of stainless steel owing to its combination of toughness and resistance to salt water corrosion. Bronze is still commonly used in ship prope... | Bronze | Wikipedia | 434 | 4169 | https://en.wikipedia.org/wiki/Bronze | Physical sciences | Chemistry | null |
The Seagram Building on New York City's Park Avenue is the "iconic glass box sheathed in bronze, designed by Mies van der Rohe." The Seagram Building was the first time that an entire building was sheathed in bronze. The General Bronze Corporation fabricated 3,200,000 pounds (1,600 tons) of bronze at its plant in Garde... | Bronze | Wikipedia | 344 | 4169 | https://en.wikipedia.org/wiki/Bronze | Physical sciences | Chemistry | null |
Bronze statues were regarded as the highest form of sculpture in Ancient Greek art, though survivals are few, as bronze was a valuable material in short supply in the Late Antique and medieval periods. Many of the most famous Greek bronze sculptures are known through Roman copies in marble, which were more likely to su... | Bronze | Wikipedia | 428 | 4169 | https://en.wikipedia.org/wiki/Bronze | Physical sciences | Chemistry | null |
Before it became possible to produce glass with acceptably flat surfaces, bronze was a standard material for mirrors. Bronze was used for this purpose in many parts of the world, probably based on independent discoveries. Bronze mirrors survive from the Egyptian Middle Kingdom (2040–1750 BCE), and China from at least .... | Bronze | Wikipedia | 441 | 4169 | https://en.wikipedia.org/wiki/Bronze | Physical sciences | Chemistry | null |
Some companies are now making saxophones from phosphor bronze (3.5 to 10% tin and up to 1% phosphorus content). Bell bronze/B20 is used to make the tone rings of many professional model banjos. The tone ring is a heavy (usually ) folded or arched metal ring attached to a thick wood rim, over which a skin, or most often... | Bronze | Wikipedia | 346 | 4169 | https://en.wikipedia.org/wiki/Bronze | Physical sciences | Chemistry | null |
Biblical references
There are over 125 references to bronze ('nehoshet'), which appears to be the Hebrew word used for copper and any of its alloys. However, the Old Testament era Hebrews are not thought to have had the capability to manufacture zinc (needed to make brass) and so it is likely that 'nehoshet' refers to ... | Bronze | Wikipedia | 292 | 4169 | https://en.wikipedia.org/wiki/Bronze | Physical sciences | Chemistry | null |
A barge a typically flat-bottomed vessel which does not have its own means of mechanical propulsion. Original use was on inland waterways, while modern use is on both inland and marine water environments. The first modern barges were pulled by tugs, but on inland waterways, most are pushed by pusher boats, or other ves... | Barge | Wikipedia | 499 | 4177 | https://en.wikipedia.org/wiki/Barge | Technology | Maritime transport | null |
The term Dumb barge was probably taken into use to end the confusion. The term Dumb barge surfaced in the early nineteenth century. It first denoted the use of a barge as a mooring platform in a fixed place. As it went up and down with the tides, it made a very convenient mooring place for steam vessels. Within a few d... | Barge | Wikipedia | 502 | 4177 | https://en.wikipedia.org/wiki/Barge | Technology | Maritime transport | null |
Crew and pole
The people who moved barges were known as lightermen. Poles are used on barges to fend off other nearby vessels or a wharf. These are often called 'pike poles'. The long pole used to maneuver or propel a barge has given rise to the saying "I wouldn't touch that [subject/thing] with a barge pole."
The 19... | Barge | Wikipedia | 469 | 4177 | https://en.wikipedia.org/wiki/Barge | Technology | Maritime transport | null |
The Transportation Institute at Texas A&M found that inland barge transportation in the US produces far fewer emissions of carbon dioxide for each ton of cargo moved compared to transport by truck or rail. According to the study, transporting cargo by barge produces 43% less greenhouse gas emissions than rail and more ... | Barge | Wikipedia | 211 | 4177 | https://en.wikipedia.org/wiki/Barge | Technology | Maritime transport | null |
Botany, also called plant science or phytology, is the branch of natural science and biology studying plants, especially their anatomy, taxonomy, and ecology. A botanist, plant scientist or phytologist is a scientist who specialises in this field. Nowadays, botanists (in the strict sense) study approximately 410,000 sp... | Botany | Wikipedia | 487 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Etymology
The term "botany" comes from the Ancient Greek word () meaning "pasture", "herbs" "grass", or "fodder"; is in turn derived from (Greek: ), "to feed" or "to graze". Traditionally, botany has also included the study of fungi and algae by mycologists and phycologists respectively, with the study of these thre... | Botany | Wikipedia | 405 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
In the mid-16th century, botanical gardens were founded in a number of Italian universities. The Padua botanical garden in 1545 is usually considered to be the first which is still in its original location. These gardens continued the practical value of earlier "physic gardens", often associated with monasteries, in wh... | Botany | Wikipedia | 367 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
During the 18th century, systems of plant identification were developed comparable to dichotomous keys, where unidentified plants are placed into taxonomic groups (e.g. family, genus and species) by making a series of choices between pairs of characters. The choice and sequence of the characters may be artificial in ke... | Botany | Wikipedia | 480 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Botany was greatly stimulated by the appearance of the first "modern" textbook, Matthias Schleiden's , published in English in 1849 as Principles of Scientific Botany. Schleiden was a microscopist and an early plant anatomist who co-founded the cell theory with Theodor Schwann and Rudolf Virchow and was among the first... | Botany | Wikipedia | 382 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Particularly since the mid-1960s there have been advances in understanding of the physics of plant physiological processes such as transpiration (the transport of water within plant tissues), the temperature dependence of rates of water evaporation from the leaf surface and the molecular diffusion of water vapour and c... | Botany | Wikipedia | 424 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Modern morphology recognises a continuum between the major morphological categories of root, stem (caulome), leaf (phyllome) and trichome. Furthermore, it emphasises structural dynamics. Modern systematics aims to reflect and discover phylogenetic relationships between plants. Modern Molecular phylogenetics largely ign... | Botany | Wikipedia | 499 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
The intersection of fields from the above pair of categories gives rise to fields such as bryogeography (the study of the distribution of mosses).
Different parts of plants also give rise to their own subfields, including xylology, carpology (or fructology) and palynology, these being the study of wood, fruit and poll... | Botany | Wikipedia | 435 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
The strictest definition of "plant" includes only the "land plants" or embryophytes, which include seed plants (gymnosperms, including the pines, and flowering plants) and the free-sporing cryptogams including ferns, clubmosses, liverworts, hornworts and mosses. Embryophytes are multicellular eukaryotes descended from ... | Botany | Wikipedia | 488 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Virtually all staple foods come either directly from primary production by plants, or indirectly from animals that eat them. Plants and other photosynthetic organisms are at the base of most food chains because they use the energy from the sun and nutrients from the soil and atmosphere, converting them into a form that... | Botany | Wikipedia | 383 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Plants and various other groups of photosynthetic eukaryotes collectively known as "algae" have unique organelles known as chloroplasts. Chloroplasts are thought to be descended from cyanobacteria that formed endosymbiotic relationships with ancient plant and algal ancestors. Chloroplasts and cyanobacteria contain the ... | Botany | Wikipedia | 508 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Plants synthesise a number of unique polymers like the polysaccharide molecules cellulose, pectin and xyloglucan from which the land plant cell wall is constructed.
Vascular land plants make lignin, a polymer used to strengthen the secondary cell walls of xylem tracheids and vessels to keep them from collapsing when a ... | Botany | Wikipedia | 283 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Medicine and materials
Phytochemistry is a branch of plant biochemistry primarily concerned with the chemical substances produced by plants during secondary metabolism. Some of these compounds are toxins such as the alkaloid coniine from hemlock. Others, such as the essential oils peppermint oil and lemon oil are usef... | Botany | Wikipedia | 385 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Sugar, starch, cotton, linen, hemp, some types of rope, wood and particle boards, papyrus and paper, vegetable oils, wax, and natural rubber are examples of commercially important materials made from plant tissues or their secondary products. Charcoal, a pure form of carbon made by pyrolysis of wood, has a long history... | Botany | Wikipedia | 511 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Herbivores eat plants, but plants can defend themselves and some species are parasitic or even carnivorous. Other organisms form mutually beneficial relationships with plants. For example, mycorrhizal fungi and rhizobia provide plants with nutrients in exchange for food, ants are recruited by ant plants to provide prot... | Botany | Wikipedia | 352 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Species boundaries in plants may be weaker than in animals, and cross species hybrids are often possible. A familiar example is peppermint, Mentha × piperita, a sterile hybrid between Mentha aquatica and spearmint, Mentha spicata. The many cultivated varieties of wheat are the result of multiple inter- and intra-specif... | Botany | Wikipedia | 484 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Most sexually reproducing organisms are diploid, with paired chromosomes, but doubling of their chromosome number may occur due to errors in cytokinesis. This can occur early in development to produce an autopolyploid or partly autopolyploid organism, or during normal processes of cellular differentiation to produce so... | Botany | Wikipedia | 484 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Model plants such as Arabidopsis thaliana are used for studying the molecular biology of plant cells and the chloroplast. Ideally, these organisms have small genomes that are well known or completely sequenced, small stature and short generation times. Corn has been used to study mechanisms of photosynthesis and phloem... | Botany | Wikipedia | 315 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Epigenetics is the study of heritable changes in gene function that cannot be explained by changes in the underlying DNA sequence but cause the organism's genes to behave (or "express themselves") differently. One example of epigenetic change is the marking of the genes by DNA methylation which determines whether they ... | Botany | Wikipedia | 507 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
The chloroplasts of plants have a number of biochemical, structural and genetic similarities to cyanobacteria, (commonly but incorrectly known as "blue-green algae") and are thought to be derived from an ancient endosymbiotic relationship between an ancestral eukaryotic cell and a cyanobacterial resident.
The algae ar... | Botany | Wikipedia | 193 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Nonvascular land plants are embryophytes that lack the vascular tissues xylem and phloem. They include mosses, liverworts and hornworts. Pteridophytic vascular plants with true xylem and phloem that reproduced by spores germinating into free-living gametophytes evolved during the Silurian period and diversified into se... | Botany | Wikipedia | 400 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Plant physiology encompasses all the internal chemical and physical activities of plants associated with life. Chemicals obtained from the air, soil and water form the basis of all plant metabolism. The energy of sunlight, captured by oxygenic photosynthesis and released by cellular respiration, is the basis of almost ... | Botany | Wikipedia | 421 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
The hypothesis that plant growth and development is coordinated by plant hormones or plant growth regulators first emerged in the late 19th century. Darwin experimented on the movements of plant shoots and roots towards light and gravity, and concluded "It is hardly an exaggeration to say that the tip of the radicle . ... | Botany | Wikipedia | 218 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Cytokinins are a class of plant hormones named for their control of cell division (especially cytokinesis). The natural cytokinin zeatin was discovered in corn, Zea mays, and is a derivative of the purine adenine. Zeatin is produced in roots and transported to shoots in the xylem where it promotes cell division, bud de... | Botany | Wikipedia | 454 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Plant anatomy is the study of the structure of plant cells and tissues, whereas plant morphology is the study of their external form.
All plants are multicellular eukaryotes, their DNA stored in nuclei. The characteristic features of plant cells that distinguish them from those of animals and fungi include a primary ce... | Botany | Wikipedia | 337 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
The root system and the shoot system are interdependent – the usually nonphotosynthetic root system depends on the shoot system for food, and the usually photosynthetic shoot system depends on water and minerals from the root system. Cells in each system are capable of creating cells of the other and producing adventit... | Botany | Wikipedia | 512 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Systematic botany is part of systematic biology, which is concerned with the range and diversity of organisms and their relationships, particularly as determined by their evolutionary history. It involves, or is related to, biological classification, scientific taxonomy and phylogenetics. Biological classification is t... | Botany | Wikipedia | 496 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Judging relationships based on shared characters requires care, since plants may resemble one another through convergent evolution in which characters have arisen independently. Some euphorbias have leafless, rounded bodies adapted to water conservation similar to those of globular cacti, but characters such as the str... | Botany | Wikipedia | 509 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
Symbols
A few symbols are in current use in botany. A number of others are obsolete; for example, Linnaeus used planetary symbols (Mars) for biennial plants, (Jupiter) for herbaceous perennials and (Saturn) for woody perennials, based on the planets' orbital periods of 2, 12 and 30 years; and Willd used (Saturn) f... | Botany | Wikipedia | 139 | 4183 | https://en.wikipedia.org/wiki/Botany | Biology and health sciences | Biology | null |
A bacteriophage (), also known informally as a phage (), is a virus that infects and replicates within bacteria and archaea. The term is derived . Bacteriophages are composed of proteins that encapsulate a DNA or RNA genome, and may have structures that are either simple or elaborate. Their genomes may encode as few as... | Bacteriophage | Wikipedia | 511 | 4185 | https://en.wikipedia.org/wiki/Bacteriophage | Biology and health sciences | Biology basics | Biology |
In 1896, Ernest Hanbury Hankin reported that something in the waters of the Ganges and Yamuna rivers in India had a marked antibacterial action against cholera and it could pass through a very fine porcelain filter. In 1915, British bacteriologist Frederick Twort, superintendent of the Brown Institution of London, disc... | Bacteriophage | Wikipedia | 483 | 4185 | https://en.wikipedia.org/wiki/Bacteriophage | Biology and health sciences | Biology basics | Biology |
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