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128-482: Sulfur (also spelled sulphur in British English ) is a chemical element ; it has symbol S and atomic number 16. It is abundant , multivalent and nonmetallic . Under normal conditions , sulfur atoms form cyclic octatomic molecules with the chemical formula S 8 . Elemental sulfur is a bright yellow, crystalline solid at room temperature . Sulfur is the tenth most abundant element by mass in
256-576: A West Germanic language that originated from the Anglo-Frisian dialects brought to Britain by Germanic settlers from various parts of what is now northwest Germany and the northern Netherlands. The resident population at this time was generally speaking Common Brittonic —the insular variety of Continental Celtic , which was influenced by the Roman occupation. This group of languages ( Welsh , Cornish , Cumbric ) cohabited alongside English into
384-435: A magnetic field , possibly to the point of behaving like a solid. The viscous forces that arise during fluid flow are distinct from the elastic forces that occur in a solid in response to shear, compression, or extension stresses. While in the latter the stress is proportional to the amount of shear deformation, in a fluid it is proportional to the rate of deformation over time. For this reason, James Clerk Maxwell used
512-559: A century as Received Pronunciation (RP). However, due to language evolution and changing social trends, some linguists argue that RP is losing prestige or has been replaced by another accent, one that the linguist Geoff Lindsey for instance calls Standard Southern British English. Others suggest that more regionally-oriented standard accents are emerging in England. Even in Scotland and Northern Ireland, RP exerts little influence in
640-471: A component of bad breath odor. Not all organic sulfur compounds smell unpleasant at all concentrations: the sulfur-containing monoterpenoid grapefruit mercaptan in small concentrations is the characteristic scent of grapefruit, but has a generic thiol odor at larger concentrations. Sulfur mustard , a potent vesicant , was used in World War ;I as a disabling agent. Sulfur–sulfur bonds are
768-436: A constant viscosity ( non-Newtonian fluids ) cannot be described by a single number. Non-Newtonian fluids exhibit a variety of different correlations between shear stress and shear rate. One of the most common instruments for measuring kinematic viscosity is the glass capillary viscometer. In coating industries, viscosity may be measured with a cup in which the efflux time is measured. There are several sorts of cup—such as
896-506: A fluid, just as thermal conductivity characterizes heat transport, and (mass) diffusivity characterizes mass transport. This perspective is implicit in Newton's law of viscosity, τ = μ ( ∂ u / ∂ y ) {\displaystyle \tau =\mu (\partial u/\partial y)} , because the shear stress τ {\displaystyle \tau } has units equivalent to
1024-508: A greater movement, normally [əʊ], [əʉ] or [əɨ]. Dropping a morphological grammatical number , in collective nouns , is stronger in British English than North American English. This is to treat them as plural when once grammatically singular, a perceived natural number prevails, especially when applying to institutional nouns and groups of people. The noun 'police', for example, undergoes this treatment: Police are investigating
1152-406: A lesser class or social status and often discounted or considered of a low intelligence. Another contribution to the standardisation of British English was the introduction of the printing press to England in the mid-15th century. In doing so, William Caxton enabled a common language and spelling to be dispersed among the entirety of England at a much faster rate. Samuel Johnson's A Dictionary of
1280-587: A major industrial product, especially in automobile tires. Because of the heat and sulfur, the process was named vulcanization , after the Roman god of the forge and volcanism . Being abundantly available in native form, sulfur was known in ancient times and is referred to in the Torah ( Genesis ). English translations of the Christian Bible commonly referred to burning sulfur as "brimstone", giving rise to
1408-415: A momentum flux , i.e., momentum per unit time per unit area. Thus, τ {\displaystyle \tau } can be interpreted as specifying the flow of momentum in the y {\displaystyle y} direction from one fluid layer to the next. Per Newton's law of viscosity, this momentum flow occurs across a velocity gradient, and the magnitude of the corresponding momentum flux
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#17327808875221536-659: A process called T-glottalisation . National media, being based in London, have seen the glottal stop spreading more widely than it once was in word endings, not being heard as "no [ʔ] " and bottle of water being heard as "bo [ʔ] le of wa [ʔ] er". It is still stigmatised when used at the beginning and central positions, such as later , while often has all but regained /t/ . Other consonants subject to this usage in Cockney English are p , as in pa [ʔ] er and k as in ba [ʔ] er. In most areas of England and Wales, outside
1664-520: A regional accent or dialect. However, about 2% of Britons speak with an accent called Received Pronunciation (also called "the King's English", "Oxford English" and " BBC English" ), that is essentially region-less. It derives from a mixture of the Midlands and Southern dialects spoken in London in the early modern period. It is frequently used as a model for teaching English to foreign learners. In
1792-416: A specific fluid state. To standardize comparisons among experiments and theoretical models, viscosity data is sometimes extrapolated to ideal limiting cases, such as the zero shear limit, or (for gases) the zero density limit. Transport theory provides an alternative interpretation of viscosity in terms of momentum transport: viscosity is the material property which characterizes momentum transport within
1920-415: A structural component used to stiffen rubber, similar to the disulfide bridges that rigidify proteins (see biological below). In the most common type of industrial "curing" or hardening and strengthening of natural rubber , elemental sulfur is heated with the rubber to the point that chemical reactions form disulfide bridges between isoprene units of the polymer. This process, patented in 1843, made rubber
2048-430: A tracer in hydrologic studies. Differences in the natural abundances can be used in systems where there is sufficient variation in the S of ecosystem components. Rocky Mountain lakes thought to be dominated by atmospheric sources of sulfate have been found to have measurably different S values than lakes believed to be dominated by watershed sources of sulfate. The radioactive S is formed in cosmic ray spallation of
2176-664: Is 1 cP divided by 1000 kg/m^3, close to the density of water. The kinematic viscosity of water at 20 °C is about 1 cSt. The most frequently used systems of US customary, or Imperial , units are the British Gravitational (BG) and English Engineering (EE). In the BG system, dynamic viscosity has units of pound -seconds per square foot (lb·s/ft ), and in the EE system it has units of pound-force -seconds per square foot (lbf·s/ft ). The pound and pound-force are equivalent;
2304-457: Is a linear combination of the shear and bulk viscosities that describes the reaction of a solid elastic material to elongation. It is widely used for characterizing polymers. In geology , earth materials that exhibit viscous deformation at least three orders of magnitude greater than their elastic deformation are sometimes called rheids . Viscosity is measured with various types of viscometers and rheometers . Close temperature control of
2432-462: Is a calculation derived from tests performed on drilling fluid used in oil or gas well development. These calculations and tests help engineers develop and maintain the properties of the drilling fluid to the specifications required. Nanoviscosity (viscosity sensed by nanoprobes) can be measured by fluorescence correlation spectroscopy . The SI unit of dynamic viscosity is the newton -second per square meter (N·s/m ), also frequently expressed in
2560-463: Is a common reagent in organic synthesis . Bromine also oxidizes sulfur to form sulfur dibromide and disulfur dibromide . Sulfur oxidizes cyanide and sulfite to give thiocyanate and thiosulfate , respectively. Sulfur reacts with many metals. Electropositive metals give polysulfide salts. Copper, zinc, and silver are attacked by sulfur; see tarnishing . Although many metal sulfides are known, most are prepared by high temperature reactions of
2688-506: Is a soft, bright-yellow solid that is odorless. It melts at 115.21 °C (239.38 °F), and boils at 444.6 °C (832.3 °F). At 95.2 °C (203.4 °F), below its melting temperature, cyclo-octasulfur begins slowly changing from α-octasulfur to the β- polymorph . The structure of the S 8 ring is virtually unchanged by this phase transition, which affects the intermolecular interactions. Cooling molten sulfur freezes at 119.6 °C (247.3 °F), as it predominantly consists of
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#17327808875222816-550: Is a viscosity tensor that maps the velocity gradient tensor ∂ v k / ∂ r ℓ {\displaystyle \partial v_{k}/\partial r_{\ell }} onto the viscous stress tensor τ i j {\displaystyle \tau _{ij}} . Since the indices in this expression can vary from 1 to 3, there are 81 "viscosity coefficients" μ i j k l {\displaystyle \mu _{ijkl}} in total. However, assuming that
2944-597: Is about 2 g/cm, depending on the allotrope; all of the stable allotropes are excellent electrical insulators. Sulfur sublimes more or less between 20 °C (68 °F) and 50 °C (122 °F). Sulfur is insoluble in water but soluble in carbon disulfide and, to a lesser extent, in other nonpolar organic solvents, such as benzene and toluene . Under normal conditions, sulfur hydrolyzes very slowly to mainly form hydrogen sulfide and sulfuric acid : The reaction involves adsorption of protons onto S 8 clusters, followed by disproportionation into
3072-725: Is also due to London-centric influences. Examples of R-dropping are car and sugar , where the R is not pronounced. British dialects differ on the extent of diphthongisation of long vowels, with southern varieties extensively turning them into diphthongs, and with northern dialects normally preserving many of them. As a comparison, North American varieties could be said to be in-between. Long vowels /iː/ and /uː/ are usually preserved, and in several areas also /oː/ and /eː/, as in go and say (unlike other varieties of English, that change them to [oʊ] and [eɪ] respectively). Some areas go as far as not diphthongising medieval /iː/ and /uː/, that give rise to modern /aɪ/ and /aʊ/; that is, for example, in
3200-511: Is based on British English, but has more influence from American English , often grouped together due to their close proximity. British English, for example, is the closest English to Indian English, but Indian English has extra vocabulary and some English words are assigned different meanings. Viscosity Viscosity is a measure of a fluid's rate-dependent resistance to a change in shape or to movement of its neighboring portions relative to one another. For liquids, it corresponds to
3328-532: Is called the rate of shear deformation or shear velocity , and is the derivative of the fluid speed in the direction parallel to the normal vector of the plates (see illustrations to the right). If the velocity does not vary linearly with y {\displaystyle y} , then the appropriate generalization is: where τ = F / A {\displaystyle \tau =F/A} , and ∂ u / ∂ y {\displaystyle \partial u/\partial y}
3456-457: Is derived from the Latin viscum (" mistletoe "). Viscum also referred to a viscous glue derived from mistletoe berries. In materials science and engineering , there is often interest in understanding the forces or stresses involved in the deformation of a material. For instance, if the material were a simple spring, the answer would be given by Hooke's law , which says that
3584-448: Is determined by the viscosity. The analogy with heat and mass transfer can be made explicit. Just as heat flows from high temperature to low temperature and mass flows from high density to low density, momentum flows from high velocity to low velocity. These behaviors are all described by compact expressions, called constitutive relations , whose one-dimensional forms are given here: where ρ {\displaystyle \rho }
3712-540: Is equal to the SI millipascal second (mPa·s). The SI unit of kinematic viscosity is square meter per second (m /s), whereas the CGS unit for kinematic viscosity is the stokes (St, or cm ·s = 0.0001 m ·s ), named after Sir George Gabriel Stokes . In U.S. usage, stoke is sometimes used as the singular form. The submultiple centistokes (cSt) is often used instead, 1 cSt = 1 mm ·s = 10 m ·s . 1 cSt
3840-414: Is explained by its production in the so-called alpha-process (one of the main classes of nuclear fusion reactions) in exploding stars. Other stable sulfur isotopes are produced in the bypass processes related with Ar, and their composition depends on a type of a stellar explosion. For example, proportionally more S comes from novae than from supernovae . On the planet Earth the sulfur isotopic composition
3968-411: Is forced through a tube, it flows more quickly near the tube's center line than near its walls. Experiments show that some stress (such as a pressure difference between the two ends of the tube) is needed to sustain the flow. This is because a force is required to overcome the friction between the layers of the fluid which are in relative motion. For a tube with a constant rate of flow, the strength of
Sulfur - Misplaced Pages Continue
4096-465: Is higher than the melting point of sulfur. Native sulfur is synthesized by anaerobic bacteria acting on sulfate minerals such as gypsum in salt domes . Significant deposits in salt domes occur along the coast of the Gulf of Mexico , and in evaporites in eastern Europe and western Asia. Native sulfur may be produced by geological processes alone. Fossil-based sulfur deposits from salt domes were once
4224-576: Is in terms of the standard (scalar) viscosity μ {\displaystyle \mu } and the bulk viscosity κ {\displaystyle \kappa } such that α = κ − 2 3 μ {\displaystyle \alpha =\kappa -{\tfrac {2}{3}}\mu } and β = γ = μ {\displaystyle \beta =\gamma =\mu } . In vector notation this appears as: where δ {\displaystyle \mathbf {\delta } }
4352-795: Is included in style guides issued by various publishers including The Times newspaper, the Oxford University Press and the Cambridge University Press . The Oxford University Press guidelines were originally drafted as a single broadsheet page by Horace Henry Hart, and were at the time (1893) the first guide of their type in English; they were gradually expanded and eventually published, first as Hart's Rules , and in 2002 as part of The Oxford Manual of Style . Comparable in authority and stature to The Chicago Manual of Style for published American English ,
4480-572: Is mildly acidic: Hydrogen sulfide gas and the hydrosulfide anion are extremely toxic to mammals, due to their inhibition of the oxygen-carrying capacity of hemoglobin and certain cytochromes in a manner analogous to cyanide and azide (see below, under precautions ). The two principal sulfur oxides are obtained by burning sulfur: Many other sulfur oxides are observed including the sulfur-rich oxides include sulfur monoxide , disulfur monoxide , disulfur dioxides, and higher oxides containing peroxo groups. Sulfur reacts with fluorine to give
4608-658: Is not a fundamental law of nature, but rather a constitutive equation (like Hooke's law , Fick's law , and Ohm's law ) which serves to define the viscosity μ {\displaystyle \mu } . Its form is motivated by experiments which show that for a wide range of fluids, μ {\displaystyle \mu } is independent of strain rate. Such fluids are called Newtonian . Gases , water , and many common liquids can be considered Newtonian in ordinary conditions and contexts. However, there are many non-Newtonian fluids that significantly deviate from this behavior. For example: Trouton 's ratio
4736-462: Is observed only at very low temperatures in superfluids ; otherwise, the second law of thermodynamics requires all fluids to have positive viscosity. A fluid that has zero viscosity (non-viscous) is called ideal or inviscid . For non-Newtonian fluid 's viscosity, there are pseudoplastic , plastic , and dilatant flows that are time-independent, and there are thixotropic and rheopectic flows that are time-dependent. The word "viscosity"
4864-516: Is produced as a byproduct of removing sulfur-containing contaminants from natural gas and petroleum . The greatest commercial use of the element is the production of sulfuric acid for sulfate and phosphate fertilizers , and other chemical processes. Sulfur is used in matches , insecticides , and fungicides . Many sulfur compounds are odoriferous, and the smells of odorized natural gas, skunk scent, bad breath , grapefruit , and garlic are due to organosulfur compounds. Hydrogen sulfide gives
4992-399: Is produced by rapid cooling of molten sulfur—for example, by pouring it into cold water. X-ray crystallography studies show that the amorphous form may have a helical structure with eight atoms per turn. The long coiled polymeric molecules make the brownish substance elastic , and in bulk it has the feel of crude rubber. This form is metastable at room temperature and gradually reverts to
5120-588: Is the dynamic viscosity of the fluid, often simply referred to as the viscosity . It is denoted by the Greek letter mu ( μ ). The dynamic viscosity has the dimensions ( m a s s / l e n g t h ) / t i m e {\displaystyle \mathrm {(mass/length)/time} } , therefore resulting in the SI units and the derived units : The aforementioned ratio u / y {\displaystyle u/y}
5248-555: Is the 10th most common element in the universe . Sulfur, usually as sulfide, is present in many types of meteorites . Ordinary chondrites contain on average 2.1% sulfur, and carbonaceous chondrites may contain as much as 6.6%. It is normally present as troilite (FeS), but there are exceptions, with carbonaceous chondrites containing free sulfur, sulfates and other sulfur compounds. The distinctive colors of Jupiter 's volcanic moon Io are attributed to various forms of molten, solid, and gaseous sulfur. In July 2024, elemental sulfur
Sulfur - Misplaced Pages Continue
5376-408: Is the density, J {\displaystyle \mathbf {J} } and q {\displaystyle \mathbf {q} } are the mass and heat fluxes, and D {\displaystyle D} and k t {\displaystyle k_{t}} are the mass diffusivity and thermal conductivity. The fact that mass, momentum, and energy (heat) transport are among
5504-425: Is the local shear velocity. This expression is referred to as Newton's law of viscosity . In shearing flows with planar symmetry, it is what defines μ {\displaystyle \mu } . It is a special case of the general definition of viscosity (see below), which can be expressed in coordinate-free form. Use of the Greek letter mu ( μ {\displaystyle \mu } ) for
5632-611: Is the ratio of extensional viscosity to shear viscosity . For a Newtonian fluid, the Trouton ratio is 3. Shear-thinning liquids are very commonly, but misleadingly, described as thixotropic. Viscosity may also depend on the fluid's physical state (temperature and pressure) and other, external , factors. For gases and other compressible fluids , it depends on temperature and varies very slowly with pressure. The viscosity of some fluids may depend on other factors. A magnetorheological fluid , for example, becomes thicker when subjected to
5760-554: Is the unit tensor. This equation can be thought of as a generalized form of Newton's law of viscosity. The bulk viscosity (also called volume viscosity) expresses a type of internal friction that resists the shearless compression or expansion of a fluid. Knowledge of κ {\displaystyle \kappa } is frequently not necessary in fluid dynamics problems. For example, an incompressible fluid satisfies ∇ ⋅ v = 0 {\displaystyle \nabla \cdot \mathbf {v} =0} and so
5888-407: Is used as a reagent to make the polymer rayon and many organosulfur compounds. Unlike carbon monoxide , carbon monosulfide is stable only as an extremely dilute gas, found between solar systems. Organosulfur compounds are responsible for some of the unpleasant odors of decaying organic matter. They are widely known as the odorant in domestic natural gas, garlic odor, and skunk spray, as well as
6016-547: The Chambers Dictionary , and the Collins Dictionary record actual usage rather than attempting to prescribe it. In addition, vocabulary and usage change with time; words are freely borrowed from other languages and other varieties of English, and neologisms are frequent. For historical reasons dating back to the rise of London in the ninth century, the form of language spoken in London and
6144-658: The East Midlands became standard English within the Court, and ultimately became the basis for generally accepted use in the law, government, literature and education in Britain. The standardisation of British English is thought to be from both dialect levelling and a thought of social superiority. Speaking in the Standard dialect created class distinctions; those who did not speak the standard English would be considered of
6272-599: The English language native to the United Kingdom of Great Britain and Northern Ireland . More narrowly, it can refer specifically to the English language in England , or, more broadly, to the collective dialects of English throughout the British Isles taken as a single umbrella variety, for instance additionally incorporating Scottish English , Welsh English , and Northern Irish English . Tom McArthur in
6400-492: The Hershey-Chase experiment . Because of the weak beta activity of S, its compounds are relatively safe as long as they are not ingested or absorbed by the body. S is created inside massive stars, at a depth where the temperature exceeds 2.5×10 K, by the fusion of one nucleus of silicon plus one nucleus of helium. As this nuclear reaction is part of the alpha process that produces elements in abundance, sulfur
6528-644: The Oxford Guide to World English acknowledges that British English shares "all the ambiguities and tensions [with] the word 'British' and as a result can be used and interpreted in two ways, more broadly or more narrowly, within a range of blurring and ambiguity". Variations exist in formal (both written and spoken) English in the United Kingdom. For example, the adjective wee is almost exclusively used in parts of Scotland, north-east England, Northern Ireland, Ireland, and occasionally Yorkshire , whereas
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#17327808875226656-493: The Royal Spanish Academy with Spanish. Standard British English differs notably in certain vocabulary, grammar, and pronunciation features from standard American English and certain other standard English varieties around the world. British and American spelling also differ in minor ways. The accent, or pronunciation system, of standard British English, based in southeastern England, has been known for over
6784-490: The Scots language or Scottish Gaelic ). Each group includes a range of dialects, some markedly different from others. The various British dialects also differ in the words that they have borrowed from other languages. Around the middle of the 15th century, there were points where within the 5 major dialects there were almost 500 ways to spell the word though . Following its last major survey of English Dialects (1949–1950),
6912-573: The University of Leeds has started work on a new project. In May 2007 the Arts and Humanities Research Council awarded a grant to Leeds to study British regional dialects. The team are sifting through a large collection of examples of regional slang words and phrases turned up by the "Voices project" run by the BBC , in which they invited the public to send in examples of English still spoken throughout
7040-610: The West Country and other near-by counties of the UK, the consonant R is not pronounced if not followed by a vowel, lengthening the preceding vowel instead. This phenomenon is known as non-rhoticity . In these same areas, a tendency exists to insert an R between a word ending in a vowel and a next word beginning with a vowel. This is called the intrusive R . It could be understood as a merger, in that words that once ended in an R and words that did not are no longer treated differently. This
7168-589: The Zahn cup and the Ford viscosity cup —with the usage of each type varying mainly according to the industry. Also used in coatings, a Stormer viscometer employs load-based rotation to determine viscosity. The viscosity is reported in Krebs units (KU), which are unique to Stormer viscometers. Vibrating viscometers can also be used to measure viscosity. Resonant, or vibrational viscometers work by creating shear waves within
7296-425: The density of the fluid ( ρ ). It is usually denoted by the Greek letter nu ( ν ): and has the dimensions ( l e n g t h ) 2 / t i m e {\displaystyle \mathrm {(length)^{2}/time} } , therefore resulting in the SI units and the derived units : In very general terms, the viscous stresses in a fluid are defined as those resulting from
7424-407: The noble gases . Sulfur polycations, S 2+ 8 , S 2+ 4 and S 2+ 16 are produced when sulfur is reacted with oxidizing agents in a strongly acidic solution. The colored solutions produced by dissolving sulfur in oleum were first reported as early as 1804 by C. F. Bucholz, but the cause of the color and the structure of the polycations involved was only determined in
7552-431: The shear viscosity . However, at least one author discourages the use of this terminology, noting that μ {\displaystyle \mu } can appear in non-shearing flows in addition to shearing flows. In fluid dynamics, it is sometimes more appropriate to work in terms of kinematic viscosity (sometimes also called the momentum diffusivity ), defined as the ratio of the dynamic viscosity ( μ ) over
7680-472: The sulfate minerals , such as gypsum (calcium sulfate), alunite (potassium aluminium sulfate), and barite (barium sulfate). On Earth, just as upon Jupiter's moon Io, elemental sulfur occurs naturally in volcanic emissions, including emissions from hydrothermal vents . The main industrial source of sulfur has become petroleum and natural gas . Common oxidation states of sulfur range from −2 to +6. Sulfur forms stable compounds with all elements except
7808-423: The "science of chemicals" ( Sanskrit : रसशास्त्र , romanized : rasaśāstra ), wrote extensively about the use of sulfur in alchemical operations with mercury, from the eighth century AD onwards. In the rasaśāstra tradition, sulfur is called "the smelly" ( गन्धक , gandhaka ). British English British English (abbreviations: BrE , en-GB , and BE ) is the set of varieties of
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#17327808875227936-408: The (among others) protein keratin , found in outer skin, hair, and feathers. Sulfur is one of the core chemical elements needed for biochemical functioning and is an elemental macronutrient for all living organisms. Sulfur forms several polyatomic molecules. The best-known allotrope is octasulfur , cyclo-S 8 . The point group of cyclo-S 8 is D 4d and its dipole moment is 0 D. Octasulfur
8064-412: The 2010s, it was thought that sulfate reduction could fractionate sulfur isotopes up to 46 permil and fractionation larger than 46 permil recorded in sediments must be due to disproportionation of sulfur compounds in the sediment. This view has changed since the 2010s as experiments showed that sulfate-reducing bacteria can fractionate to 66 permil. As substrates for disproportionation are limited by
8192-629: The 21st century. RP, while long established as the standard English accent around the globe due to the spread of the British Empire , is distinct from the standard English pronunciation in some parts of the world; most prominently, RP notably contrasts with standard North American accents. In the 21st century, dictionaries like the Oxford English Dictionary , the Longman Dictionary of Contemporary English ,
8320-532: The 3rd century, the Chinese had discovered that sulfur could be extracted from pyrite . Chinese Daoists were interested in sulfur's flammability and its reactivity with certain metals, yet its earliest practical uses were found in traditional Chinese medicine . The Wujing Zongyao of 1044 AD described various formulas for Chinese black powder , which is a mixture of potassium nitrate ( KNO 3 ), charcoal , and sulfur. Indian alchemists, practitioners of
8448-491: The BG and EE systems. Nonstandard units include the reyn (lbf·s/in ), a British unit of dynamic viscosity. In the automotive industry the viscosity index is used to describe the change of viscosity with temperature. The reciprocal of viscosity is fluidity , usually symbolized by ϕ = 1 / μ {\displaystyle \phi =1/\mu } or F = 1 / μ {\displaystyle F=1/\mu } , depending on
8576-468: The Couette flow, a fluid is trapped between two infinitely large plates, one fixed and one in parallel motion at constant speed u {\displaystyle u} (see illustration to the right). If the speed of the top plate is low enough (to avoid turbulence), then in steady state the fluid particles move parallel to it, and their speed varies from 0 {\displaystyle 0} at
8704-836: The English Language (1755) was a large step in the English-language spelling reform , where the purification of language focused on standardising both speech and spelling. By the early 20th century, British authors had produced numerous books intended as guides to English grammar and usage, a few of which achieved sufficient acclaim to have remained in print for long periods and to have been reissued in new editions after some decades. These include, most notably of all, Fowler's Modern English Usage and The Complete Plain Words by Sir Ernest Gowers . Detailed guidance on many aspects of writing British English for publication
8832-666: The Germanic schwein ) is the animal in the field bred by the occupied Anglo-Saxons and pork (like the French porc ) is the animal at the table eaten by the occupying Normans. Another example is the Anglo-Saxon cu meaning cow, and the French bœuf meaning beef. Cohabitation with the Scandinavians resulted in a significant grammatical simplification and lexical enrichment of the Anglo-Frisian core of English;
8960-922: The Oxford Manual is a fairly exhaustive standard for published British English that writers can turn to in the absence of specific guidance from their publishing house. British English is the basis of, and very similar to, Commonwealth English . Commonwealth English is English as spoken and written in the Commonwealth countries , though often with some local variation. This includes English spoken in Australia , Malta , New Zealand , Nigeria , and South Africa . It also includes South Asian English used in South Asia, in English varieties in Southeast Asia , and in parts of Africa. Canadian English
9088-712: The South East, there are significantly different accents; the Cockney accent spoken by some East Londoners is strikingly different from Received Pronunciation (RP). Cockney rhyming slang can be (and was initially intended to be) difficult for outsiders to understand, although the extent of its use is often somewhat exaggerated. Londoners speak with a mixture of accents, depending on ethnicity, neighbourhood, class, age, upbringing, and sundry other factors. Estuary English has been gaining prominence in recent decades: it has some features of RP and some of Cockney. Immigrants to
9216-550: The UK in recent decades have brought many more languages to the country and particularly to London. Surveys started in 1979 by the Inner London Education Authority discovered over 125 languages being spoken domestically by the families of the inner city's schoolchildren. Notably Multicultural London English , a sociolect that emerged in the late 20th century spoken mainly by young, working-class people in multicultural parts of London . Since
9344-576: The United Kingdom , as well as within the countries themselves. The major divisions are normally classified as English English (or English as spoken in England (which is itself broadly grouped into Southern English , West Country , East and West Midlands English and Northern English ), Northern Irish English (in Northern Ireland), Welsh English (not to be confused with the Welsh language ), and Scottish English (not to be confused with
9472-465: The West Scottish accent. Phonological features characteristic of British English revolve around the pronunciation of the letter R, as well as the dental plosive T and some diphthongs specific to this dialect. Once regarded as a Cockney feature, in a number of forms of spoken British English, /t/ has become commonly realised as a glottal stop [ʔ] when it is in the intervocalic position, in
9600-490: The activity of sulfate-reducing bacteria in the time of formation of the sample, or suggest the main sources of sulfur in ecosystems. However, there are ongoing discussions over the real reason for the δS shifts, biological activity or postdeposit alteration. For example, when sulfide minerals are precipitated, isotopic equilibration among solids and liquid may cause small differences in the δS values of co-genetic minerals. The differences between minerals can be used to estimate
9728-410: The adjective little is predominant elsewhere. Nevertheless, there is a meaningful degree of uniformity in written English within the United Kingdom, and this could be described by the term British English . The forms of spoken English, however, vary considerably more than in most other areas of the world where English is spoken and so a uniform concept of British English is more difficult to apply to
9856-431: The atmospheric Ar . This fact may be used to verify the presence of recent (up to 1 year) atmospheric sediments in various materials. This isotope may be obtained artificially by different ways. In practice, the reaction Cl + n → S + p is used by irradiating potassium chloride with neutrons. The isotope S is used in various sulfur-containing compounds as a radioactive tracer for many biological studies, for example,
9984-488: The award of the grant in 2007, Leeds University stated: that they were "very pleased"—and indeed, "well chuffed"—at receiving their generous grant. He could, of course, have been "bostin" if he had come from the Black Country , or if he was a Scouser he would have been well "made up" over so many spondoolicks, because as a Geordie might say, £460,000 is a "canny load of chink". Most people in Britain speak with
10112-662: The basis for commercial production in the United States, Russia, Turkmenistan, and Ukraine. Such sources have become of secondary commercial importance, and most are no longer worked but commercial production is still carried out in the Osiek mine in Poland. Common naturally occurring sulfur compounds include the sulfide minerals , such as pyrite (iron sulfide), cinnabar (mercury sulfide), galena (lead sulfide), sphalerite (zinc sulfide), and stibnite (antimony sulfide); and
10240-425: The bottom to u {\displaystyle u} at the top. Each layer of fluid moves faster than the one just below it, and friction between them gives rise to a force resisting their relative motion. In particular, the fluid applies on the top plate a force in the direction opposite to its motion, and an equal but opposite force on the bottom plate. An external force is therefore required in order to keep
10368-565: The characteristic odor to rotting eggs and other biological processes. Sulfur is an essential element for all life, almost always in the form of organosulfur compounds or metal sulfides. Amino acids (two proteinogenic : cysteine and methionine , and many other non-coded : cystine , taurine , etc.) and two vitamins ( biotin and thiamine ) are organosulfur compounds crucial for life. Many cofactors also contain sulfur, including glutathione , and iron–sulfur proteins . Disulfides , S–S bonds, confer mechanical strength and insolubility of
10496-420: The compensating force is proportional to the fluid's viscosity. In general, viscosity depends on a fluid's state, such as its temperature, pressure, and rate of deformation. However, the dependence on some of these properties is negligible in certain cases. For example, the viscosity of a Newtonian fluid does not vary significantly with the rate of deformation. Zero viscosity (no resistance to shear stress )
10624-501: The composition of reaction products. While reaction between sulfur and oxygen under normal conditions gives sulfur dioxide (oxidation state +4), formation of sulfur trioxide (oxidation state +6) requires a temperature of 400–600 °C (750–1,100 °F) and presence of a catalyst. In reactions with elements of lesser electronegativity , it reacts as an oxidant and forms sulfides, where it has oxidation state −2. Sulfur reacts with nearly all other elements except noble gases, even with
10752-602: The convention used, measured in reciprocal poise (P , or cm · s · g ), sometimes called the rhe . Fluidity is seldom used in engineering practice. At one time the petroleum industry relied on measuring kinematic viscosity by means of the Saybolt viscometer , and expressing kinematic viscosity in units of Saybolt universal seconds (SUS). Other abbreviations such as SSU ( Saybolt seconds universal ) or SUV ( Saybolt universal viscosity ) are sometimes used. Kinematic viscosity in centistokes can be converted from SUS according to
10880-622: The country. The BBC Voices project also collected hundreds of news articles about how the British speak English from swearing through to items on language schools. This information will also be collated and analysed by Johnson's team both for content and for where it was reported. "Perhaps the most remarkable finding in the Voices study is that the English language is as diverse as ever, despite our increased mobility and constant exposure to other accents and dialects through TV and radio". When discussing
11008-443: The crystalline molecular allotrope, which is no longer elastic. This process happens over a matter of hours to days, but can be rapidly catalyzed. Sulfur has 23 known isotopes , four of which are stable: S ( 94.99% ± 0.26% ), S ( 0.75% ± 0.02% ), S ( 4.25% ± 0.24% ), and S ( 0.01% ± 0.01% ). Other than S, with a half-life of 87 days, the radioactive isotopes of sulfur have half-lives less than 3 hours. The preponderance of S
11136-465: The dynamic viscosity (sometimes also called the absolute viscosity ) is common among mechanical and chemical engineers , as well as mathematicians and physicists. However, the Greek letter eta ( η {\displaystyle \eta } ) is also used by chemists, physicists, and the IUPAC . The viscosity μ {\displaystyle \mu } is sometimes also called
11264-465: The elements. Geoscientists also study the isotopes of metal sulfides in rocks and sediment to study environmental conditions in the Earth's past. Some of the main classes of sulfur-containing organic compounds include the following: Compounds with carbon–sulfur multiple bonds are uncommon, an exception being carbon disulfide , a volatile colorless liquid that is structurally similar to carbon dioxide. It
11392-457: The equivalent forms pascal - second (Pa·s), kilogram per meter per second (kg·m ·s ) and poiseuille (Pl). The CGS unit is the poise (P, or g·cm ·s = 0.1 Pa·s), named after Jean Léonard Marie Poiseuille . It is commonly expressed, particularly in ASTM standards, as centipoise (cP). The centipoise is convenient because the viscosity of water at 20 °C is about 1 cP, and one centipoise
11520-409: The fluid do not depend on the distance the fluid has been sheared; rather, they depend on how quickly the shearing occurs. Viscosity is the material property which relates the viscous stresses in a material to the rate of change of a deformation (the strain rate). Although it applies to general flows, it is easy to visualize and define in a simple shearing flow, such as a planar Couette flow . In
11648-459: The fluid is essential to obtain accurate measurements, particularly in materials like lubricants, whose viscosity can double with a change of only 5 °C. A rheometer is used for fluids that cannot be defined by a single value of viscosity and therefore require more parameters to be set and measured than is the case for a viscometer. For some fluids, the viscosity is constant over a wide range of shear rates ( Newtonian fluids ). The fluids without
11776-426: The force experienced by a spring is proportional to the distance displaced from equilibrium. Stresses which can be attributed to the deformation of a material from some rest state are called elastic stresses. In other materials, stresses are present which can be attributed to the deformation rate over time . These are called viscous stresses. For instance, in a fluid such as water the stresses which arise from shearing
11904-405: The highly reactive sulfur tetrafluoride and the highly inert sulfur hexafluoride . Whereas fluorine gives S(IV) and S(VI) compounds, chlorine gives S(II) and S(I) derivatives. Thus, sulfur dichloride , disulfur dichloride , and higher chlorosulfanes arise from the chlorination of sulfur. Sulfuryl chloride and chlorosulfuric acid are derivatives of sulfuric acid; thionyl chloride (SOCl 2 )
12032-458: The idea of two different morphemes, one that causes the double negation, and one that is used for the point or the verb. Standard English in the United Kingdom, as in other English-speaking nations, is widely enforced in schools and by social norms for formal contexts but not by any singular authority; for instance, there is no institution equivalent to the Académie française with French or
12160-413: The informal concept of thickness ; for example, syrup has a higher viscosity than water . Viscosity is defined scientifically as a force multiplied by a time divided by an area. Thus its SI units are newton-seconds per square meter, or pascal-seconds. Viscosity quantifies the internal frictional force between adjacent layers of fluid that are in relative motion. For instance, when a viscous fluid
12288-491: The largest documented single crystal measuring 22 cm × 16 cm × 11 cm (8.7 in × 6.3 in × 4.3 in). Historically, Sicily was a major source of sulfur in the Industrial Revolution . Lakes of molten sulfur up to about 200 m (660 ft) in diameter have been found on the sea floor, associated with submarine volcanoes , at depths where the boiling point of water
12416-523: The last southern Midlands accent to use the broad "a" in words like bath or grass (i.e. barth or grarss ). Conversely crass or plastic use a slender "a". A few miles northwest in Leicestershire the slender "a" becomes more widespread generally. In the town of Corby , five miles (8 km) north, one can find Corbyite which, unlike the Kettering accent, is largely influenced by
12544-414: The late 1960s. S 2+ 8 is deep blue, S 2+ 4 is yellow and S 2+ 16 is red. Reduction of sulfur gives various polysulfides with the formula S x , many of which have been obtained in crystalline form. Illustrative is the production of sodium tetrasulfide : Some of these dianions dissociate to give radical anions , such as S − 3 gives the blue color of
12672-518: The later Norman occupation led to the grafting onto that Germanic core of a more elaborate layer of words from the Romance branch of the European languages. This Norman influence entered English largely through the courts and government. Thus, English developed into a "borrowing" language of great flexibility and with a huge vocabulary . Dialects and accents vary amongst the four countries of
12800-529: The liquid. In this method, the sensor is submerged in the fluid and is made to resonate at a specific frequency. As the surface of the sensor shears through the liquid, energy is lost due to its viscosity. This dissipated energy is then measured and converted into a viscosity reading. A higher viscosity causes a greater loss of energy. Extensional viscosity can be measured with various rheometers that apply extensional stress . Volume viscosity can be measured with an acoustic rheometer . Apparent viscosity
12928-457: The mass internal migration to Northamptonshire in the 1940s and given its position between several major accent regions, it has become a source of various accent developments. In Northampton the older accent has been influenced by overspill Londoners. There is an accent known locally as the Kettering accent, which is a transitional accent between the East Midlands and East Anglian . It is
13056-463: The modern period, but due to their remoteness from the Germanic languages , influence on English was notably limited . However, the degree of influence remains debated, and it has recently been argued that its grammatical influence accounts for the substantial innovations noted between English and the other West Germanic languages. Initially, Old English was a diverse group of dialects, reflecting
13184-435: The most relevant processes in continuum mechanics is not a coincidence: these are among the few physical quantities that are conserved at the microscopic level in interparticle collisions. Thus, rather than being dictated by the fast and complex microscopic interaction timescale, their dynamics occurs on macroscopic timescales, as described by the various equations of transport theory and hydrodynamics. Newton's law of viscosity
13312-566: The notoriously unreactive metal iridium (yielding iridium disulfide ). Some of those reactions require elevated temperatures. Sulfur forms over 30 solid allotropes , more than any other element. Besides S 8 , several other rings are known. Removing one atom from the crown gives S 7 , which is of a deeper yellow than S 8 . HPLC analysis of "elemental sulfur" reveals an equilibrium mixture of mainly S 8 , but with S 7 and small amounts of S 6 . Larger rings have been prepared, including S 12 and S 18 . Amorphous or "plastic" sulfur
13440-406: The product of sulfate reduction , the isotopic effect of disproportionation should be less than 16 permil in most sedimentary settings. In forest ecosystems, sulfate is derived mostly from the atmosphere; weathering of ore minerals and evaporites contribute some sulfur. Sulfur with a distinctive isotopic composition has been used to identify pollution sources, and enriched sulfur has been added as
13568-419: The reaction products. The second, fourth and sixth ionization energies of sulfur are 2252 kJ/mol, 4556 kJ/mol and 8495.8 kJ/mol, respectively. The composition of reaction products of sulfur with oxidants (and its oxidation state) depends on whether releasing of reaction energy overcomes these thresholds. Applying catalysts and/or supply of external energy may vary sulfur's oxidation state and
13696-515: The relative velocity of different fluid particles. As such, the viscous stresses must depend on spatial gradients of the flow velocity. If the velocity gradients are small, then to a first approximation the viscous stresses depend only on the first derivatives of the velocity. (For Newtonian fluids, this is also a linear dependence.) In Cartesian coordinates, the general relationship can then be written as where μ i j k ℓ {\displaystyle \mu _{ijk\ell }}
13824-508: The rock lapis lazuli . This reaction highlights a distinctive property of sulfur: its ability to catenate (bind to itself by formation of chains). Protonation of these polysulfide anions produces the polysulfanes , H 2 S x , where x = 2, 3, and 4. Ultimately, reduction of sulfur produces sulfide salts: The interconversion of these species is exploited in the sodium–sulfur battery . Treatment of sulfur with hydrogen gives hydrogen sulfide . When dissolved in water, hydrogen sulfide
13952-401: The spoken language. Globally, countries that are former British colonies or members of the Commonwealth tend to follow British English, as is the case for English used by European Union institutions. In China, both British English and American English are taught. The UK government actively teaches and promotes English around the world and operates in over 200 countries . English is
14080-463: The temperature of equilibration. The δC and δS of coexisting carbonate minerals and sulfides can be used to determine the pH and oxygen fugacity of the ore-bearing fluid during ore formation. Scientists measure the sulfur isotopes of minerals in rocks and sediments to study the redox conditions in past oceans. Sulfate-reducing bacteria in marine sediment fractionate sulfur isotopes as they take in sulfate and produce sulfide . Prior to
14208-555: The term fugitive elasticity for fluid viscosity. However, many liquids (including water) will briefly react like elastic solids when subjected to sudden stress. Conversely, many "solids" (even granite ) will flow like liquids, albeit very slowly, even under arbitrarily small stress. Such materials are best described as viscoelastic —that is, possessing both elasticity (reaction to deformation) and viscosity (reaction to rate of deformation). Viscoelastic solids may exhibit both shear viscosity and bulk viscosity. The extensional viscosity
14336-515: The term " fire-and-brimstone " sermons , in which listeners are reminded of the fate of eternal damnation that await the unbelieving and unrepentant. It is from this part of the Bible that Hell is implied to "smell of sulfur" (likely due to its association with volcanic activity). According to the Ebers Papyrus , a sulfur ointment was used in ancient Egypt to treat granular eyelids. Sulfur
14464-715: The term containing κ {\displaystyle \kappa } drops out. Moreover, κ {\displaystyle \kappa } is often assumed to be negligible for gases since it is 0 {\displaystyle 0} in a monatomic ideal gas . One situation in which κ {\displaystyle \kappa } can be important is the calculation of energy loss in sound and shock waves , described by Stokes' law of sound attenuation , since these phenomena involve rapid expansions and compressions. The defining equations for viscosity are not fundamental laws of nature, so their usefulness, as well as methods for measuring or calculating
14592-603: The theft of work tools worth £500 from a van at the Sprucefield park and ride car park in Lisburn. A football team can be treated likewise: Arsenal have lost just one of 20 home Premier League matches against Manchester City. This tendency can be observed in texts produced already in the 19th century. For example, Jane Austen , a British author, writes in Chapter 4 of Pride and Prejudice , published in 1813: All
14720-583: The top plate moving at constant speed. In many fluids, the flow velocity is observed to vary linearly from zero at the bottom to u {\displaystyle u} at the top. Moreover, the magnitude of the force, F {\displaystyle F} , acting on the top plate is found to be proportional to the speed u {\displaystyle u} and the area A {\displaystyle A} of each plate, and inversely proportional to their separation y {\displaystyle y} : The proportionality factor
14848-403: The traditional accent of Newcastle upon Tyne , 'out' will sound as 'oot', and in parts of Scotland and North-West England, 'my' will be pronounced as 'me'. Long vowels /iː/ and /uː/ are diphthongised to [ɪi] and [ʊu] respectively (or, more technically, [ʏʉ], with a raised tongue), so that ee and oo in feed and food are pronounced with a movement. The diphthong [oʊ] is also pronounced with
14976-513: The two systems differ only in how force and mass are defined. In the BG system the pound is a basic unit from which the unit of mass (the slug ) is defined by Newton's Second Law , whereas in the EE system the units of force and mass (the pound-force and pound-mass respectively) are defined independently through the Second Law using the proportionality constant g c . Kinematic viscosity has units of square feet per second (ft /s) in both
15104-449: The universe and the fifth most common on Earth. Though sometimes found in pure, native form, sulfur on Earth usually occurs as sulfide and sulfate minerals . Being abundant in native form, sulfur was known in ancient times, being mentioned for its uses in ancient India , ancient Greece , China , and ancient Egypt . Historically and in literature sulfur is also called brimstone , which means "burning stone". Almost all elemental sulfur
15232-750: The varied origins of the Anglo-Saxon kingdoms of England. One of these dialects, Late West Saxon , eventually came to dominate. The original Old English was then influenced by two waves of invasion: the first was by speakers of the Scandinavian branch of the Germanic family, who settled in parts of Britain in the eighth and ninth centuries; the second was the Normans in the 11th century, who spoke Old Norman and ultimately developed an English variety of this called Anglo-Norman . These two invasions caused English to become "mixed" to some degree (though it
15360-403: The viscosity depends only space- and time-dependent macroscopic fields (such as temperature and density) defining local equilibrium. Nevertheless, viscosity may still carry a non-negligible dependence on several system properties, such as temperature, pressure, and the amplitude and frequency of any external forcing. Therefore, precision measurements of viscosity are only defined with respect to
15488-571: The viscosity rank-2 tensor is isotropic reduces these 81 coefficients to three independent parameters α {\displaystyle \alpha } , β {\displaystyle \beta } , γ {\displaystyle \gamma } : and furthermore, it is assumed that no viscous forces may arise when the fluid is undergoing simple rigid-body rotation, thus β = γ {\displaystyle \beta =\gamma } , leaving only two independent parameters. The most usual decomposition
15616-500: The viscosity, must be established using separate means. A potential issue is that viscosity depends, in principle, on the full microscopic state of the fluid, which encompasses the positions and momenta of every particle in the system. Such highly detailed information is typically not available in realistic systems. However, under certain conditions most of this information can be shown to be negligible. In particular, for Newtonian fluids near equilibrium and far from boundaries (bulk state),
15744-568: The world are good and agreeable in your eyes. However, in Chapter 16, the grammatical number is used. The world is blinded by his fortune and consequence. Some dialects of British English use negative concords, also known as double negatives . Rather than changing a word or using a positive, words like nobody, not, nothing, and never would be used in the same sentence. While this does not occur in Standard English, it does occur in non-standard dialects. The double negation follows
15872-417: The β-S 8 molecules. Between its melting and boiling temperatures, octasulfur changes its allotrope again, turning from β-octasulfur to γ-sulfur, again accompanied by a lower density but increased viscosity due to the formation of polymers . At higher temperatures, the viscosity decreases as depolymerization occurs. Molten sulfur assumes a dark red color above 200 °C (392 °F). The density of sulfur
16000-630: Was accidentally discovered to exist on Mars after the Curiosity rover drove over and crushed a rock, revealing sulfur crystals inside it. Sulfur is the fifth most common element by mass in the Earth. Elemental sulfur can be found near hot springs and volcanic regions in many parts of the world, especially along the Pacific Ring of Fire ; such volcanic deposits are mined in Indonesia, Chile, and Japan. These deposits are polycrystalline, with
16128-549: Was determined by the Sun. Though it was assumed that the distribution of different sulfur isotopes would be more or less equal, it has been found that proportions of the two most abundant sulfur isotopes S and S varies in different samples. Assaying of the isotope ratio ( δS ) in the samples suggests their chemical history, and with support of other methods, it allows to age-date the samples, estimate temperature of equilibrium between ore and water, determine pH and oxygen fugacity , identify
16256-422: Was never a truly mixed language in the strictest sense of the word; mixed languages arise from the cohabitation of speakers of different languages, who develop a hybrid tongue for basic communication). The more idiomatic, concrete and descriptive English is, the more it is from Anglo-Saxon origins. The more intellectual and abstract English is, the more it contains Latin and French influences, e.g. swine (like
16384-636: Was used for fumigation in preclassical Greece ; this is mentioned in the Odyssey . Pliny the Elder discusses sulfur in book 35 of his Natural History , saying that its best-known source is the island of Melos . He mentions its use for fumigation, medicine, and bleaching cloth. A natural form of sulfur known as shiliuhuang ( 石硫黄 ) was known in China since the 6th century BC and found in Hanzhong . By
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