title: Republic of the Congo

text: Following the revision of the French constitution that established the Fifth Republic in 1958, AEF dissolved into its constituent parts, each of which became an autonomous colony within the French Community. During these reforms, Middle Congo became known as the Republic of the Congo in 1958 and published its first constitution in 1959. Antagonism between the Mbochis (who favored Jacques Opangault) and the Laris and Kongos (who favored Fulbert Youlou, the first black mayor elected in French Equatorial Africa) resulted in a series of riots in Brazzaville in February 1959, which the French Army subdued.


title: Republic of the Congo

text: Elections took place in April 1959. By the time the Congo became independent in August 1960, Opangault, the former opponent of Youlou, agreed to serve under him. Youlou, an avid anti-communist, became the first President of the Republic of the Congo. Since the political tension was so high in Pointe-Noire, Youlou moved the capital to Brazzaville.


title: Republic of the Congo

text: The Republic of the Congo became fully independent from France on 15 August 1960. Youlou ruled as the country's first president until labor elements and rival political parties instigated a 3-day uprising that ousted him. The Congolese military took over the country and installed a civilian provisional government headed by Alphonse Massamba-Débat.


title: Republic of the Congo

text: Under the 1963 constitution, Massamba-Débat was elected president for a 5-year term. During Massamba-Débat's term in office, the regime adopted "scientific socialism" as the country's constitutional ideology. In 1964, Congo for the first time sent an official team with a single athlete at the Olympic Games. In 1965, Congo established relations with the Soviet Union, the People's Republic of China, North Korea, and North Vietnam. On the economic and social level, Massamba-Débat led a healthy and rigorous management. Under his presidency, the Congo began to industrialize and the standard of living of the Congolese improved. Some large production units with large workforces were built: the textile factory of Kinsoundi, the palm groves of Etoumbi, the match factory of Bétou, the shipyards of Yoro, etc. Health centers were created as well as school groups (colleges and elementary school). The country's school enrollment rate became the highest in Black Africa. At the same time, Brazzaville became a center for left-wing exiles from all over Central Africa. On the night of February 14 to 15, 1965, 3 public officials of the Republic of the Congo were kidnapped: (prosecutor of the Republic), (President of the Supreme Court), and (director of the Congolese Information Agency). The bodies of 2 of these men were later found, mutilated, by the Congo River. Massamba-Débat's regime invited some hundred Cuban army troops into the country to train his party's militia units. These troops helped his government survive a "coup d'état" in 1966 led by paratroopers loyal to future President Marien Ngouabi. Massamba-Débat was unable to reconcile institutional, tribal, and ideological factions within the country and his regime ended with a bloodless "coup" in September 1968.


title: Republic of the Congo

text: Marien Ngouabi, who had participated in the coup, assumed the presidency on 31 December 1968. 1 year later, Ngouabi proclaimed the Congo Africa's first "people's republic", the People's Republic of the Congo, and announced the decision of the National Revolutionary Movement to change its name to the Congolese Labour Party (PCT). He survived an attempted "coup" in 1972 and was assassinated on 16 March1977. An 11-member Military Committee of the Party (CMP) was then named to head an interim government, with Joachim Yhombi-Opango serving as president. 2 years later, Yhombi-Opango was forced from power, and Denis Sassou Nguesso became the new president.


title: Republic of the Congo

text: Sassou Nguesso aligned the country with the Eastern Bloc and signed a 20-year friendship pact with the Soviet Union. Over the years, Sassou had to rely more on political repression and less on patronage to maintain his dictatorship. The collapse of the Soviet Union in 1991 resulted in the ending of Soviet aid to prop up the regime, and it abdicated power.


title: Republic of the Congo

text: Pascal Lissouba who became Congo's first elected president (1992–1997) during the period of multi-party democracy attempted to implement economic reforms with IMF backing to liberalize the economy. In June 1996, IMF approved a 3-year SDR69.5m (US$100m) enhanced structural adjustment facility (ESAF) and was on the verge of announcing a renewed annual agreement when civil war broke out in Congo in 1997.


title: Republic of the Congo

text: Congo's democratic progress was derailed in 1997 when Lissouba and Sassou started to fight for power in the civil war. As presidential elections scheduled for July 1997 approached, tensions between the Lissouba and Sassou camps mounted. On 5 June, President Lissouba's government forces surrounded Sassou's compound in Brazzaville, and Sassou ordered members of his private militia (known as "Cobras") to resist. Thus began a 4-month conflict that destroyed or damaged some of Brazzaville and caused tens of thousands of civilian deaths. In October, the Angolan government began an invasion of Congo to install Sassou in power and the Lissouba government fell. After that, Sassou declared himself president.


title: Republic of the Congo

text: In the elections in 2002, Sassou won with almost 90% of the vote cast. His 2 main rivals, Lissouba and Bernard Kolelas, were prevented from competing. A remaining rival, André Milongo advised his supporters to boycott the elections and then withdrew from the race. A constitution, agreed upon by referendum in January 2002, granted the president new powers, extended his term to 7 years and introduced a new bicameral assembly. International observers took issue with the organization of the presidential election and the constitutional referendum, both of which were reminiscent in their organization of Congo's era of the 1-party state. Following the presidential elections, fighting restarted in the Pool region between government forces and rebels led by Pastor Ntumi; a peace treaty to end the conflict was signed in April 2003.


title: Republic of the Congo

text: Sassou won the following presidential election in July 2009. According to the Congolese Observatory of Human Rights, a non-governmental organization, the election was marked by "very low" turnout and "fraud and irregularities". In March 2015, Sassou announced that he wanted to run for yet another term in office and a constitutional referendum in October resulted in a changed constitution that allowed him to run during the 2016 presidential election. He won the election believed by some to be fraudulent. After violent protests in the capital, Sassou attacked the Pool region where the Ninja rebels of the civil war used to be based, in what was believed to be a distraction. This led to a revival of the Ninja rebels who launched attacks against the army in April 2016, leading 80,000 people to flee their homes. A ceasefire deal was signed in December 2017.


title: Republic of the Congo

text: The government of the Republic is a semi-presidential system with an elected president who appoints the Council of Ministers, or Cabinet. The council, including the Prime Minister, is selected from the elected representatives in Parliament. Since the 1990s, the country has had a multi-party political system which is dominated by President Denis Sassou Nguesso. Sassou Nguesso is backed by his own Congolese Labour Party () as well as a range of smaller parties.


title: Republic of the Congo

text: Sassou's regime has seen corruption revelations, with attempts to censor them. One French investigation found over 110 bank accounts and dozens of "lavish properties" in France. Sassou denounced embezzlement investigations as "racist" and "colonial". Denis Christel Sassou-Nguesso, son of Denis Sassou Nguesso, has been named in association with the Panama Papers.


title: Republic of the Congo

text: On 27 March 2015, Sassou Nguesso announced that his government would hold a referendum on changing the country's 2002 constitution to allow him to run for a third consecutive term in office. On 25 October, the government held a referendum on allowing Sassou Nguesso to run in the next election. The government claimed that the proposal was approved by 92% of voters, with 72% of eligible voters participating. The opposition who boycotted the referendum said that the government's statistics were false and the vote was a fake one. The election raised questions and was accompanied by civil unrest and police shootings of protesters; at least 18 people were killed by security forces during opposition rallies leading up to the referendum held in October.


title: Republic of the Congo

text: It is divided into 12 "départements" (departments). Departments are divided into communes and districts.


title: Republic of the Congo

text: Some Pygmies belong from birth to Bantus in a relationship some refer to as slavery. The Congolese Human Rights Observatory says that the Pygmies are treated as property in the same way as pets. On 30 December 2010, the Congolese parliament adopted a law to promote and protect the rights of indigenous peoples. This law is "the first" of its kind in Africa.


title: Republic of the Congo

text: Natural landscapes ranged from the savanna plains in the North Niari flooded forests, to the Congo River, to the rugged mountains and forests of Mayombe, and 170 km of beaches along the Atlantic coast.


title: Republic of the Congo

text: Congo is located in the central-western part of sub-Saharan Africa, along the Equator, lying between latitudes 4°N and 5°S, and longitudes 11° and 19°E. To the south and east of it is the Democratic Republic of the Congo. It is bounded by Gabon to the west, Cameroon and the Central African Republic to the north, and Cabinda (Angola) to the southwest. It has a coast on the Atlantic Ocean.


title: Republic of the Congo

text: The southwest is a coastal plain for which the primary drainage is the Kouilou-Niari River; the interior of the country consists of a central plateau between 2 basins to the south and north. Forests are under increasing exploitation pressure. Congo had a 2018 Forest Landscape Integrity Index mean score of 8.89/10, ranking it 12th globally out of 172 countries.


title: Republic of the Congo

text: Congo lies within 4 terrestrial ecoregions: Atlantic Equatorial coastal forests, Northwestern Congolian lowland forests, Western Congolian swamp forests, and Western Congolian forest–savanna mosaic. Since the country is located on the Equator, the climate is more consistent year-round, with the average day temperature a humid and nights generally between and . The average yearly rainfall ranges from in the Niari Valley in the south to over in central parts. The dry season is from June to August, while in the majority of the country, the wet season has 2 rainfall maxima: 1 in March–May and another in September–November.


title: Republic of the Congo

text: In 2006–07, researchers from the Wildlife Conservation Society studied gorillas in "heavily forested" regions centered on the Ouesso District of the Sangha Region. They suggest a population on the order of 125,000 western lowland gorillas whose isolation from humans has been mostly preserved by "inhospitable" swamps.


title: Republic of the Congo

text: The economy is a mixture of village agriculture and handicrafts, an industrial sector based mainly on petroleum, support services, and a government characterized by budget problems and "overstaffing". Petroleum extraction has supplanted forestry as the mainstay of the economy. In 2008, the oil sector accounted for 65% of the GDP, 85% of government revenue, and 92% of exports. The country has untapped mineral wealth.


title: Republic of the Congo

text: In the 1980s, rising oil revenues enabled the government to finance larger-scale development projects. GDP grew an average of 5% annually. The government has mortgaged a portion of its petroleum earnings, contributing to a "shortage of revenues". On 12 January 1994, the devaluation of Franc Zone currencies by 50% resulted in an inflation of 46% in 1994, and inflation has subsided since.


title: Republic of the Congo

text: Economic reform efforts continued with the support of international organizations, including the World Bank and the International Monetary Fund. The reform program came to a halt in June 1997 when civil war erupted. When Sassou Nguesso returned to power in October 1997, he publicly expressed interest in moving forward on economic reforms and privatization and in renewing cooperation with international financial institutions. Economic progress was "badly hurt" by slumping oil prices and the resumption of armed conflict in December 1998, which "worsened" the republic's budget deficit.


title: Republic of the Congo

text: The administration presides over an "uneasy internal peace" and faces "difficult" economic problems of stimulating recovery and reducing poverty, with record-high oil prices since 2003. Natural gas and diamonds are other exports, while Congo was excluded from the Kimberley Process in 2004 amid allegations that most of its diamond exports were, in fact, being smuggled out of the neighboring Democratic Republic of the Congo; it was re-admitted to the group in 2007.


title: Republic of the Congo

text: The Republic of the Congo has untapped base metal, gold, iron, and phosphate deposits. It is a member of the Organization for the Harmonization of Business Law in Africa (OHADA). The Congolese government signed an agreement in 2009 to lease 200,000 hectares of land to South African farmers to reduce its dependence on imports.


title: Republic of the Congo

text: The GDP of the Republic of the Congo grew by 6% in 2014 and is expected to have grown by 7.5% in 2015.


title: Republic of the Congo

text: Congo–Ocean Railway was built by forced laborers during the 1930s. Some colonial architectural heritage is preserved. Restoration of architectural works is underway in Brazzaville, for example, at the Basilica of Sainte-Anne du Congo, which was completed in 2011.


title: Republic of the Congo

text: Its population is concentrated in the southwestern portion, leaving the areas of tropical jungle in the north virtually uninhabited. 70% of its total population lives in some urban areas, namely in Brazzaville, Pointe-Noire, or 1 of the cities or villages lining the , railway which connects the 2 cities. In rural areas, industrial and commercial activity has declined in some years, leaving rural economies dependent on the government for support and subsistence.


title: Republic of the Congo

text: Ethnologue recognizes 62 spoken languages in the country. The Kongo are the largest ethnic group and form roughly half of the population. The most significant subgroups of the Kongo are Laari, in Brazzaville and Pool regions, and the Vili, around Pointe-Noire and along the Atlantic coast. The second largest group is the Teke, who live to the north of Brazzaville, with 16.9% of the population. Mbochi live in the north, east and in Brazzaville and form 13.1% of the population. Pygmies make up 2% of Congo's population.


title: Republic of the Congo

text: Before the 1997 war, about 9,000 Europeans and other non-Africans lived in Congo, most of whom were French; a fraction of this number remains. Around 300 American expatriates reside in the Congo.


title: Republic of the Congo

text: According to CIA World Factbook, the people of the Republic of the Congo are largely a mix of Catholics (33.1%), Awakening Lutherans (22.3%), and other Protestants (19.9%) as of 2007. Followers of Islam make up 1.6%; this is primarily due to an influx of foreign workers into the urban centers.


title: Republic of the Congo

text: According to a 2011–12 survey, the total fertility rate was 5.1 children born per woman, with 4.5 in urban areas and 6.5 in rural areas.


title: Republic of the Congo

text: , the HIV/AIDS prevalence was at 2.8% among 15- to 49-year-olds. Health expenditure was at US$30 per capita in 2004. A proportion of the population is undernourished, and malnutrition is a problem in Congo-Brazzaville. There were 20 physicians per 100,000 persons in the 2000s (decade).


title: Republic of the Congo

text: , the maternal mortality rate was 560 deaths/100,000 live births, and the infant mortality rate was 59.34 deaths/1,000 live births. Female genital mutilation (FGM) is confined to limited geographic areas.


title: Republic of the Congo

text: Public expenditure of the GDP was less in 2002–05 than in 1991. Public education is theoretically free and mandatory for under-16-year-olds, and in practice, expenses exist. In 2005 net primary enrollment rate was 44%, a drop from 79% in 1991.


title: Viscosity

text: The viscosity of a fluid is a measure of its resistance to deformation at a given rate. It is a standard mechanical quantity. For liquids, it corresponds to the informal concept of "thickness": for example, syrup has a higher viscosity than water.


title: Viscosity

text: Viscosity quantifies the internal frictional force between adjacent layers of fluid that are in relative motion. For instance, when a viscous fluid is forced through a tube, it flows more quickly near the tube's axis 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 the compensating force is proportional to the fluid's viscosity.


title: Viscosity

text: 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) 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 is called "ideal" or "inviscid".


title: Viscosity

text: The word "viscosity" is derived from the Latin "" ("mistletoe"). "Viscum" also referred to a viscous glue derived from mistletoe berries.


title: Viscosity

text: In materials science and engineering, one is often interested 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 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 rate of change of the deformation over time. These are called viscous stresses. For instance, in a fluid such as water the stresses which arise from shearing the fluid do not depend on the "distance" the fluid has been sheared; rather, they depend on how "quickly" the shearing occurs.


title: Viscosity

text: 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.


title: Viscosity

text: In the Couette flow, a fluid is trapped between two infinitely large plates, one fixed and one in parallel motion at constant speed formula_1 (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 formula_2 at the bottom to formula_1 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 the top plate moving at constant speed.


title: Viscosity

text: In many fluids, the flow velocity is observed to vary linearly from zero at the bottom to formula_1 at the top. Moreover, the magnitude of the force, formula_5, acting on the top plate is found to be proportional to the speed formula_1 and the area formula_7 of each plate, and inversely proportional to their separation formula_8:


title: Viscosity

text: The proportionality factor is the "dynamic viscosity" of the fluid, often simply referred to as the "viscosity". It is denoted by the Greek letter mu (). The dynamic viscosity has the dimensions formula_10, therefore resulting in the SI units and the derived units:


title: Viscosity

text: The aforementioned ratio formula_12 is called the "rate of shear deformation" or "shear velocity", and is the derivative of the fluid speed in the direction perpendicular to the normal vector of the plates (see illustrations to the right). If the velocity does not vary linearly with formula_8, then the appropriate generalization is:


title: Viscosity

text: where formula_15, and formula_16 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" formula_17. It is a special case of the general definition of viscosity (see below), which can be expressed in coordinate-free form.


title: Viscosity

text: Use of the Greek letter mu (formula_17) for 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 (formula_19) is also used by chemists, physicists, and the IUPAC. The viscosity formula_17 is sometimes also called the "shear viscosity". However, at least one author discourages the use of this terminology, noting that formula_17 can appear in non-shearing flows in addition to shearing flows.


title: Viscosity

text: 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 () over the density of the fluid (). It is usually denoted by the Greek letter nu ():


title: Viscosity

text: In very general terms, the viscous stresses in a fluid are defined as those resulting from 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


title: Viscosity

text: where formula_26 is a viscosity tensor that maps the velocity gradient tensor formula_27 onto the viscous stress tensor formula_28. Since the indices in this expression can vary from 1 to 3, there are 81 "viscosity coefficients" formula_29 in total. However, assuming that the viscosity rank-4 tensor is isotropic reduces these 81 coefficients to three independent parameters formula_30, formula_31, formula_32:


title: Viscosity

text: and furthermore, it is assumed that no viscous forces may arise when the fluid is undergoing simple rigid-body rotation, thus formula_34, leaving only two independent parameters. The most usual decomposition is in terms of the standard (scalar) viscosity formula_17 and the bulk viscosity formula_36 such that formula_37 and formula_38. In vector notation this appears as:


title: Viscosity

text: where formula_40 is the unit tensor, and the dagger formula_41 denotes the transpose. This equation can be thought of as a generalized form of Newton's law of viscosity.


title: Viscosity

text: 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 formula_36 is frequently not necessary in fluid dynamics problems. For example, an incompressible fluid satisfies formula_43 and so the term containing formula_36 drops out. Moreover, formula_36 is often assumed to be negligible for gases since it is formula_2 in a monatomic ideal gas. One situation in which formula_36 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.


title: Viscosity

text: The defining equations for viscosity are not fundamental laws of nature, so their usefulness, as well as methods for measuring or calculating 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), the viscosity depends only space- and time-dependent macroscopic fields (such as temperature and density) defining local equilibrium.


title: Viscosity

text: 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


title: Viscosity

text: with respect to 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.


title: Viscosity

text: Transport theory provides an alternative interpretation of viscosity in terms of momentum transport: viscosity is the material property which characterizes momentum transport within 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, formula_48, because the shear stress formula_49 has units equivalent to a momentum flux, i.e., momentum per unit time per unit area. Thus, formula_49 can be interpreted as specifying the flow of momentum in the formula_8 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 is determined by the viscosity.


title: Viscosity

text: 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:


title: Viscosity

text: where formula_53 is the density, formula_54 and formula_55 are the mass and heat fluxes, and formula_56 and formula_57 are the mass diffusivity and thermal conductivity. The fact that mass, momentum, and energy (heat) transport are among 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.


title: Viscosity

text: Newton's law of viscosity 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 formula_17. Its form is motivated by experiments which show that for a wide range of fluids, formula_17 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:


title: Viscosity

text: Trouton's ratio 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.


title: Viscosity

text: Even for a Newtonian fluid, the viscosity usually depends on its composition and temperature. 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 a magnetic field, possibly to the point of behaving like a solid.


title: Viscosity

text: 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, Maxwell used the term "fugitive elasticity" for fluid viscosity.


title: Viscosity

text: 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).


title: Viscosity

text: Viscoelastic solids may exhibit both shear viscosity and bulk viscosity. The extensional viscosity 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.


title: Viscosity

text: In geology, earth materials that exhibit viscous deformation at least three orders of magnitude greater than their elastic deformation are sometimes called rheids.


title: Viscosity

text: Viscosity is measured with various types of viscometers and rheometers. 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. Close temperature control of the fluid is essential to obtain accurate measurements, particularly in materials like lubricants, whose viscosity can double with a change of only 5 °C.


title: Viscosity

text: For some fluids, the viscosity is constant over a wide range of shear rates (Newtonian fluids). The fluids without 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.


title: Viscosity

text: One of the most common instruments for measuring kinematic viscosity is the glass capillary viscometer.


title: Viscosity

text: 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 the Zahn cup and the Ford viscosity cup—with the usage of each type varying mainly according to the industry.


title: Viscosity

text: 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.


title: Viscosity

text: Vibrating viscometers can also be used to measure viscosity. Resonant, or vibrational viscometers work by creating shear waves within 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.


title: Viscosity

text: Apparent viscosity 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.


title: Viscosity

text: Nanoviscosity (viscosity sensed by nanoprobes) can be measured by fluorescence correlation spectroscopy.


title: Viscosity

text: The SI unit of dynamic viscosity is the newton-second per square meter (N·s/m), also frequently expressed in 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 is equal to the SI millipascal second (mPa·s).


title: Viscosity

text: 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. The kinematic viscosity of water at 20 °C is about 1 cSt.


title: Viscosity

text: 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; 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".


title: Viscosity

text: Nonstandard units include the reyn, a British unit of dynamic viscosity. In the automotive industry the viscosity index is used to describe the change of viscosity with temperature.


title: Viscosity

text: The reciprocal of viscosity is "fluidity", usually symbolized by formula_60 or formula_61, depending on the convention used, measured in "reciprocal poise" (P, or cm·s·g), sometimes called the "rhe". Fluidity is seldom used in engineering practice.


title: Viscosity

text: 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 the arithmetic and the reference table provided in ASTM D 2161.


title: Viscosity

text: Momentum transport in gases is mediated by discrete molecular collisions, and in liquids by attractive forces that bind molecules close together. Because of this, the dynamic viscosities of liquids are typically much larger than those of gases. In addition, viscosity tends to increase with temperature in gases and decrease with temperature in liquids.


title: Viscosity

text: Above the liquid-gas critical point, the liquid and gas phases are replaced by a single supercritical phase. In this regime, the mechanisms of momentum transport interpolate between liquid-like and gas-like behavior.


title: Viscosity

text: For example, along a supercritical isobar (constant-pressure surface), the kinematic viscosity decreases at low temperature and increases at high temperature, with a minimum in between. A rough estimate for the value


title: Viscosity

text: where formula_63 is the Planck constant, formula_64 is the electron mass, and formula_65 is the molecular mass.


title: Viscosity

text: In general, however, the viscosity of a system depends in detail on how the molecules constituting the system interact, and there are no simple but correct formulas for it. The simplest exact expressions are the Green–Kubo relations for the linear shear viscosity or the "transient time correlation function" expressions derived by Evans and Morriss in 1988. Although these expressions are each exact, calculating the viscosity of a dense fluid using these relations currently requires the use of molecular dynamics computer simulations. Somewhat more progress can be made for a dilute gas, as elementary assumptions about how gas molecules move and interact lead to a basic understanding of the molecular origins of viscosity. More sophisticated treatments can be constructed by systematically coarse-graining the equations of motion of the gas molecules. An example of such a treatment is Chapman–Enskog theory, which derives expressions for the viscosity of a dilute gas from the Boltzmann equation.


title: Viscosity

text: Viscosity in gases arises principally from the molecular diffusion that transports momentum between layers of flow. An elementary calculation for a dilute gas at temperature formula_66 and density formula_53 gives


title: Viscosity

text: where formula_69 is the Boltzmann constant, formula_65 the molecular mass, and formula_30 a numerical constant on the order of formula_72. The quantity formula_73, the mean free path, measures the average distance a molecule travels between collisions. Even without "a priori" knowledge of formula_30, this expression has nontrivial implications. In particular, since formula_73 is typically inversely proportional to density and increases with temperature, formula_17 itself should increase with temperature and be independent of density at fixed temperature. In fact, both of these predictions persist in more sophisticated treatments, and accurately describe experimental observations. By contrast, liquid viscosity typically decreases with temperature.


title: Viscosity

text: In this case formula_73 is independent of temperature, so formula_81. For more complicated molecular models, however, formula_73 depends on temperature in a non-trivial way, and simple kinetic arguments as used here are inadequate. More fundamentally, the notion of a mean free path becomes imprecise for particles that interact over a finite range, which limits the usefulness of the concept for describing real-world gases.


title: Viscosity

text: A technique developed by Sydney Chapman and David Enskog in the early 1900s allows a more refined calculation of formula_17. It is based on the Boltzmann equation, which provides a statistical description of a dilute gas in terms of intermolecular interactions. The technique allows accurate calculation of formula_17 for molecular models that are more realistic than rigid elastic spheres, such as those incorporating intermolecular attractions. Doing so is necessary to reproduce the correct temperature dependence of formula_17, which experiments show increases more rapidly than the formula_86 trend predicted for rigid elastic spheres. Indeed, the Chapman–Enskog analysis shows that the predicted temperature dependence can be tuned by varying the parameters in various molecular models. A simple example is the Sutherland model, which describes rigid elastic spheres with "weak" mutual attraction. In such a case, the attractive force can be treated perturbatively, which leads to a simple expression for formula_17:


title: Viscosity

text: where formula_89 is independent of temperature, being determined only by the parameters of the intermolecular attraction. To connect with experiment, it is convenient to rewrite as


title: Viscosity

text: where formula_91 is the viscosity at temperature formula_92. If formula_17 is known from experiments at formula_94 and at least one other temperature, then formula_89 can be calculated. Expressions for formula_17 obtained in this way are qualitatively accurate for a number of simple gases. Slightly more sophisticated models, such as the Lennard-Jones potential, may provide better agreement with experiments, but only at the cost of a more opaque dependence on temperature. In some systems, the assumption of spherical symmetry must be abandoned as well, as is the case for vapors with highly polar molecules like HO. In these cases, the Chapman–Enskog analysis is significantly more complicated.


title: Viscosity

text: In the kinetic-molecular picture, a non-zero bulk viscosity arises in gases whenever there are non-negligible relaxational timescales governing the exchange of energy between the translational energy of molecules and their internal energy, e.g. rotational and vibrational. As such, the bulk viscosity is formula_2 for a monatomic ideal gas, in which the internal energy of molecules in negligible, but is nonzero for a gas like carbon dioxide, whose molecules possess both rotational and vibrational energy.


title: Viscosity

text: In contrast with gases, there is no simple yet accurate picture for the molecular origins of viscosity in liquids.


title: Viscosity

text: At the simplest level of description, the relative motion of adjacent layers in a liquid is opposed primarily by attractive molecular forces


title: Viscosity

text: acting across the layer boundary. In this picture, one (correctly) expects viscosity to decrease with increasing temperature. This is because


title: Viscosity

text: increasing temperature increases the random thermal motion of the molecules, which makes it easier for them to overcome their attractive interactions.


title: Viscosity

text: Building on this visualization, a simple theory can be constructed in analogy with the discrete structure of a solid: groups of molecules in a liquid


title: Viscosity

text: are visualized as forming "cages" which surround and enclose single molecules. These cages can be occupied or unoccupied, and


title: Viscosity

text: Due to random thermal motion, a molecule "hops" between cages at a rate which varies inversely with the strength of molecular attractions. In equilibrium these "hops" are not biased in any direction.


title: Viscosity

text: On the other hand, in order for two adjacent layers to move relative to each other, the "hops" must be biased in the direction


title: Viscosity

text: of the relative motion. The force required to sustain this directed motion can be estimated for a given shear rate, leading to


title: Viscosity

text: where formula_98 is the Avogadro constant, formula_99 is the Planck constant, formula_100 is the volume of a mole of liquid, and formula_101 is the normal boiling point. This result has the same form as the well-known empirical relation


title: Viscosity

text: where formula_7 and formula_103 are constants fit from data. On the other hand, several authors express caution with respect to this model.


title: Viscosity

text: Errors as large as 30% can be encountered using equation (), compared with fitting equation () to experimental data. More fundamentally, the physical assumptions underlying equation () have been criticized. It has also been argued that the exponential dependence in equation () does not necessarily describe experimental observations more accurately than simpler, non-exponential expressions.


title: Viscosity

text: In light of these shortcomings, the development of a less ad hoc model is a matter of practical interest.


title: Viscosity

text: Foregoing simplicity in favor of precision, it is possible to write rigorous expressions for viscosity starting from the fundamental equations of motion for molecules. A classic example


title: Viscosity

text: are given as averages over multiparticle correlation functions and are therefore difficult to apply in practice.


title: Viscosity

text: In general, empirically derived expressions (based on existing viscosity measurements) appear to be the only consistently reliable means of calculating viscosity in liquids.


title: Viscosity

text: The same molecular-kinetic picture of a single component gas can also be applied to a gaseous mixture. For instance, in the Chapman–Enskog approach the viscosity formula_104 of a binary mixture of gases can be written in terms of the individual component viscosities formula_105, their respective volume fractions, and the intermolecular interactions. As for the single-component gas, the dependence of formula_104 on the parameters of the intermolecular interactions enters through various collisional integrals which may not be expressible in terms of elementary functions. To obtain usable expressions for formula_104 which reasonably match experimental data, the collisional integrals typically must be evaluated using some combination of analytic calculation and empirical fitting. An example of such a procedure is the Sutherland approach for the single-component gas, discussed above.


title: Viscosity

text: As for pure liquids, the viscosity of a blend of liquids is difficult to predict from molecular principles. One method is to extend the molecular "cage" theory presented above for a pure liquid. This can be done with varying levels of sophistication. One expression resulting from such an analysis is the Lederer–Roegiers equation for a binary mixture:


title: Viscosity

text: where formula_30 is an empirical parameter, and formula_110 and formula_105 are the respective mole fractions and viscosities of the component liquids.


title: Viscosity

text: Since blending is an important process in the lubricating and oil industries, a variety of empirical and propriety equations exist for predicting the viscosity of a blend.


title: Viscosity

text: Depending on the solute and range of concentration, an aqueous electrolyte solution can have either a larger or smaller viscosity compared with pure water at the same temperature and pressure. For instance, a 20% saline (sodium chloride) solution has viscosity over 1.5 times that of pure water, whereas a 20% potassium iodide solution has viscosity about 0.91 times that of pure water.


title: Viscosity

text: An idealized model of dilute electrolytic solutions leads to the following prediction for the viscosity formula_112 of a solution:


title: Viscosity

text: where formula_91 is the viscosity of the solvent, formula_115 is the concentration, and formula_7 is a positive constant which depends on both solvent and solute properties. However, this expression is only valid for very dilute solutions, having formula_115 less than 0.1 mol/L. For higher concentrations, additional terms are necessary which account for higher-order molecular correlations:


title: Viscosity

text: where formula_103 and formula_120 are fit from data. In particular, a negative value of formula_103 is able to account for the decrease in viscosity observed in some solutions. Estimated values of these constants are shown below for sodium chloride and potassium iodide at temperature 25 °C (mol = mole, L = liter).


title: Viscosity

text: In a suspension of solid particles (e.g. micron-size spheres suspended in oil), an effective viscosity formula_122 can be defined in terms of stress and strain components which are averaged over a volume large compared with the distance between the suspended particles, but small with respect to macroscopic dimensions. Such suspensions generally exhibit non-Newtonian behavior. However, for dilute systems in steady flows, the behavior is Newtonian and expressions for formula_122 can be derived directly from the particle dynamics. In a very dilute system, with volume fraction formula_124, interactions between the suspended particles can be ignored. In such a case one can explicitly calculate the flow field around each particle independently, and combine the results to obtain formula_125. For spheres, this results in the Einstein equation:


title: Viscosity

text: where formula_91 is the viscosity of the suspending liquid. The linear dependence on formula_128 is a consequence of neglecting interparticle interactions. For dilute systems in general, one expects formula_125 to take the form


title: Viscosity

text: where the coefficient formula_103 may depend on the particle shape (e.g. spheres, rods, disks). Experimental determination of the precise value of formula_103 is difficult, however: even the prediction formula_133 for spheres has not been conclusively validated, with various experiments finding values in the range formula_134. This deficiency has been attributed to difficulty in controlling experimental conditions.


title: Viscosity

text: In denser suspensions, formula_122 acquires a nonlinear dependence on formula_128, which indicates the importance of interparticle interactions. Various analytical and semi-empirical schemes exist for capturing this regime. At the most basic level, a term quadratic in formula_128 is added to formula_125:


title: Viscosity

text: and the coefficient formula_140 is fit from experimental data or approximated from the microscopic theory. However, some authors advise caution in applying such simple formulas since non-Newtonian behavior appears in dense suspensions (formula_141 for spheres), or in suspensions of elongated or flexible particles.


title: Viscosity

text: There is a distinction between a suspension of solid particles, described above, and an emulsion. The latter is a suspension of tiny droplets, which themselves may exhibit internal circulation. The presence of internal circulation can decrease the observed effective viscosity, and different theoretical or semi-empirical models must be used.


title: Viscosity

text: In the high and low temperature limits, viscous flow in amorphous materials (e.g. in glasses and melts) has the Arrhenius form:


title: Viscosity

text: where is a relevant activation energy, given in terms of molecular parameters; is temperature; is the molar gas constant; and is approximately a constant. The activation energy takes a different value depending on whether the high or low temperature limit is being considered: it changes from a high value at low temperatures (in the glassy state) to a low value at high temperatures (in the liquid state).


title: Viscosity

text: For intermediate temperatures, formula_143 varies nontrivially with temperature and the simple Arrhenius form fails. On the other hand, the two-exponential equation


title: Viscosity

text: where formula_7, formula_103, formula_120, formula_56 are all constants, provides a good fit to experimental data over the entire range of temperatures, while at the same time reducing to the correct Arrhenius form in the low and high temperature limits. This expression can be motivated from various theoretical models of amorphous materials at the atomic level.


title: Viscosity

text: A two-exponential equation for the viscosity can be derived within the Dyre shoving model of supercooled liquids, where the Arrhenius energy barrier is identified with the high-frequency shear modulus times a characteristic shoving volume. Upon specifying the temperature dependence of the shear modulus via thermal expansion and via the repulsive part of the intermolecular potential, another two-exponential equation is retrieved:


title: Viscosity

text: where formula_150 denotes the high-frequency shear modulus of the material evaluated at a temperature equal to the glass transition temperature formula_151, formula_152 is the so-called shoving volume, i.e. it is the characteristic volume of the group of atoms involved in the shoving event by which an atom/molecule escapes from the cage of nearest-neighbours, typically on the order of the volume occupied by few atoms. Furthermore, formula_153 is the thermal expansion coefficient of the material, formula_154 is a parameter which measures the steepness of the power-law rise of the ascending flank of the first peak of the radial distribution function, and is quantitatively related to the repulsive part of the interatomic potential. Finally, formula_155 denotes the Boltzmann constant.


title: Viscosity

text: In the study of turbulence in fluids, a common practical strategy is to ignore the small-scale vortices (or eddies) in the motion and to calculate a large-scale motion with an "effective" viscosity, called the "eddy viscosity", which characterizes the transport and dissipation of energy in the smaller-scale flow (see large eddy simulation). In contrast to the viscosity of the fluid itself, which must be positive by the second law of thermodynamics, the eddy viscosity can be negative.


title: Viscosity

text: Because viscosity depends continuously on temperature and pressure, it cannot be fully characterized by a finite number


title: Viscosity

text: of experimental measurements. Predictive formulas become necessary if experimental values are not available


title: Viscosity

text: at the temperatures and pressures of interest. This capability is important for thermophysical simulations,


title: Viscosity

text: in which the temperature and pressure of a fluid can vary continuously with space and time. A similar situation is encountered


title: Viscosity

text: for mixtures of pure fluids, where the viscosity depends continuously on the concentration ratios of the constituent fluids


title: Viscosity

text: For the simplest fluids, such as dilute monatomic gases and their mixtures, "ab initio" quantum mechanical computations can accurately predict viscosity in terms


title: Viscosity

text: of fundamental atomic constants, i.e., without reference to existing viscosity measurements. For the special case of dilute helium,


title: Viscosity

text: uncertainties in the "ab initio" calculated viscosity are two order of magnitudes smaller than uncertainties in experimental values.


title: Viscosity

text: For most fluids, such high-accuracy, first-principles computations are not feasible. Rather, theoretical or empirical expressions


title: Viscosity

text: must be fit to existing viscosity measurements. If such an expression is fit to high-fidelity data over a large range of temperatures


title: Viscosity

text: and pressures, then it is called a "reference correlation" for that fluid. Reference correlations have been published for


title: Viscosity

text: many pure fluids; a few examples are water, carbon dioxide, ammonia, benzene, and xenon. Many of these cover temperature and pressure ranges that encompass gas, liquid, and supercritical phases.


title: Viscosity

text: Thermophysical modeling software often relies on reference correlations for predicting viscosity at user-specified temperature and pressure.


title: Viscosity

text: Viscosity can also be computed using formulas that express it in terms of the statistics of individual particle


title: Viscosity

text: trajectories. These formulas include the Green–Kubo relations for the linear shear viscosity and the "transient time correlation function"


title: Viscosity

text: The advantage of these expressions is that they are formally exact and valid for general systems. The disadvantage is that they require detailed


title: Viscosity

text: knowledge of particle trajectories, available only in computationally expensive simulations such as molecular dynamics.


title: Viscosity

text: An accurate model for interparticle interactions is also required, which may be difficult to obtain for complex molecules.


title: Viscosity

text: Observed values of viscosity vary over several orders of magnitude, even for common substances (see the order of magnitude table below). For instance, a 70% sucrose (sugar) solution has a viscosity over 400 times that of water, and 26000 times that of air. More dramatically, pitch has been estimated to have a viscosity 230 billion times that of water.


title: Viscosity

text: The dynamic viscosity formula_17 of water is about 0.89 mPa·s at room temperature (25 °C). As a function of temperature in kelvins, the viscosity can be estimated using the semi-empirical Vogel-Fulcher-Tammann equation:


title: Viscosity

text: where "A" = 0.02939 mPa·s, "B" = 507.88 K, and "C" = 149.3 K. Experimentally determined values of the viscosity are also given in the table below. The values at 20 °C are a useful reference: there, the dynamic viscosity is about 1 cP and the kinematic viscosity is about 1 cSt.


title: Viscosity

text: Under standard atmospheric conditions (25 °C and pressure of 1 bar), the dynamic viscosity of air is 18.5 μPa·s, roughly 50 times smaller than the viscosity of water at the same temperature. Except at very high pressure, the viscosity of air depends mostly on the temperature. Among the many possible approximate formulas for the temperature dependence (see "Temperature dependence of viscosity"), one is:


title: Viscosity

text: which is accurate in the range −20 °C to 400 °C. For this formula to be valid, the temperature must be given in kelvins; formula_159 then corresponds to the viscosity in Pa·s.


title: Viscosity

text: The following table illustrates the range of viscosity values observed in common substances. Unless otherwise noted, a temperature of 25 °C and a pressure of 1 atmosphere are assumed.


title: Viscosity

text: The values listed are representative estimates only, as they do not account for measurement uncertainties, variability in material definitions, or non-Newtonian behavior.


title: Jiří Procházka

text: Jiří Procházka (; ; born October 14, 1992) is a Czech mixed martial artist. He currently competes in the Light Heavyweight division in the Ultimate Fighting Championship (UFC), where he is the former UFC Light Heavyweight Champion. He was the inaugural Rizin Fighting Federation Light Heavyweight Champion and the inaugural Gladiator Fighting Championship Light Heavyweight Champion. As of November 14, 2022, he is #10 in the UFC men's pound-for-pound rankings, and as of December 6, 2022, he is #1 in the UFC light heavyweight rankings.


title: Jiří Procházka

text: Procházka was born on October 14, 1992 in the south Moravian part of Czechoslovakia ("now Czech Republic"). Procházka's father died when he was 6 years old. In his youth, Procházka played amateur football for TJ Družstevník Hostěradice. He was also an active freestyle BMX rider and a floorball player.


title: Jiří Procházka

text: As a teen, Procházka partook in street fights almost weekly, getting into more than 100 of them. This eventually led him to join the hooligan club tied to Prochazka's local soccer team, FC Zbrojovka Brno, where he would take part in organized group street fights with clubs of other teams, even participating in 30-on-30 brawls.


title: Jiří Procházka

text: Procházka first encountered mixed martial arts before beginning high school, after a friend showed him videos of kickboxer Ramon Dekkers and mixed martial artists Mirko Filipovic and Fedor Emelianenko. After watching the film Never Back Down, he began to train in martial arts, in particular Thai boxing. In 2011, Procházka won the National Championship at 86 kilograms.


title: Jiří Procházka

text: Procházka made his professional MMA debut in April 2012 for the Gladiator Fighting Championship, the biggest promotion in his native Czech Republic at the time. He amassed a 7-2 record within his first two years of fighting professionally.


title: Jiří Procházka

text: In his tenth professional bout, he won the inaugural GCF Light Heavyweight Championship in the back-and-forth fight against Czech MMA pioneer Martin Šolc via flying knee knockout on December 7, 2013 at GCF 26 FN. Video of the bout went viral in the Czech Republic and Procházka was also awarded a post-fight bonus.<ref name="AktualneCZ2014/03/21">VIDEO Svátek MMA: Do klece se vrací brutální Procházka!, "Aktuálně" 2014/03/21. Retrieved on 12 July 2020.</ref> The fight was later awarded 'Czech Fight of the Year' by major media outlets.


title: Jiří Procházka

text: Procházka defended his title against Tomáš Penz on June 6, 2014 at GCF 28: Cage Fight 4. He won the fight via technical knockout due to a flying knee in 41 seconds.


title: Jiří Procházka

text: Procházka signed a deal with the Rizin Fighting Federation shortly before his win against Evgeni Kondratov. After amassing a record of 14–2–1 during his first three years in the sport, Procházka as the first Czech entered the Rizin Fighting Federation in 2015.


title: Jiří Procházka

text: Procházka made his promotional debut against Satoshi Ishii on December 29, 2015 in the World Grand Prix 2015 –100 kg tournament at the Rizin FF's first event Saraba no Utake. He won the quarter-final fight via knockout in the first round.<ref name="MMAFighting2015/12/29">Rizin Results: Aoki vs. Sakuraba, "MMA Fighting" 2015/12/29. Retrieved on 2 September 2020.</ref>


title: Jiří Procházka

text: Procházka's next fight in the Rizin FF's -100 kg tournament was at Iza no Mai on December 31, 2015. He won the semi-final fight against Vadim Nemkov via technical knockout. Later that same night, he lost in the final round against Muhammed Lawal via knockout in the first round.<ref name="BleacherReport2015/12/31">Rizin FF 2: Highlights, Results and Top Knockouts from Thursday's Fights, "Bleacher Report" 2015/12/31. Retrieved on 2 September 2020.</ref> Procházka weighed in at 95.9 kgs (211.5 pounds) for the tournament.


title: Jiří Procházka

text: Procházka faced Kazuyuki Fujita on April 17, 2016 at Rizin 1 at a catchweight of 110 kgs (242.5 pounds). Procházka weighed in at 98.6 kgs (217.3 pounds) for the bout. He won the fight via technical knockout in the first round.<ref name="MMAFighting2016/04/17">Rizin 1 Results: Fujita vs. Prochazka, "MMA Fighting" 2016/04/17. Retrieved on 2 September 2020.</ref>


title: Jiří Procházka

text: Procházka faced Mark Tanios on September 25, 2016 at Rizin 2 - Rizin Fighting World Grand Prix 2016: Opening Round. He won the fight via unanimous decision. Procházka suffered a knee injury during the fight and was subsequently pulled from the tournament.


title: Jiří Procházka

text: Procházka faced Willian Roberto Alves on September 29, 2017, at Fusion FN 16 - Cage Fight, the homecoming event organized by his team. He won the fight via technical knockout in the first round.


title: Jiří Procházka

text: Procházka faced Karl Albrektsson on December 29, 2017 at Rizin Fighting World Grand Prix 2017 - Bantamweight Tournament: 2nd Round. He won the fight via technical knockout in the first round.


title: Jiří Procházka

text: Procházka faced Bruno Henrique Cappelozza on July 28, 2018, at Rizin 11. He won the fight via knockout in the first round.<ref name="MMAFighting2018/07/29">Takanori Gomi knocks out Melvin Guillard at Rizin 11, "MMA Fighting" 2018/07/29. Retrieved on 12 July 2020.</ref>


title: Jiří Procházka

text: Procházka faced Jake Heun on September 30, 2018 at Rizin 13. He won the fight via technical knockout in the first round.


title: Jiří Procházka

text: Procházka was scheduled to face Emanuel Newton on December 31, 2018 at Rizin 14. However, Newton was pulled out of the fight, citing a rib injury. Procházka remained on the card and was rescheduled to face Brandon Halsey.<ref name="MMASucka.RIZIN.14.Newton/Halsey">Brandon Halsey replaces Newton vs. Jiri Prochazka at RIZIN 14, "MMA Sucka" 2020/12/18. Retrieved on 28 April 2021.</ref> He won the fight via technical knockout in the first round.<ref name="Sherdog2020/07/10">BY THE NUMBERS: VOLKAN OEZDEMIR VS. JIRI PROCHAZKA, "Sherdog" 2020/07/10. Retrieved on 12 July 2020.</ref>


title: Jiří Procházka

text: Procházka faced Muhammed Lawal in rematch on April 21, 2019 at Rizin 15 for the inaugural Rizin FF Light Heavyweight Championship. He won the fight via technical knockout in the third round.


title: Jiří Procházka

text: Procházka faced Fábio Maldonado on October 12, 2019 at Rizin 19: Lightweight Grand Prix 1st Round at a catchweight of 100 kgs (220.4 pounds). Procházka weighed in at 97.90 kgs (215.8 pounds) for the bout. He won the fight via knockout in the first round.<ref name="MMAFighting2019/10/12">Rizin 19 results: Jiri Prochazka blasts through Fabio Maldonado, Kai Asakura overwhelms Ulka Sasaki, "MMA Fighting" 2019/10/12. Retrieved on 12 July 2020.</ref>


title: Jiří Procházka

text: Procházka defended his title against C. B. Dollaway on December 31, 2019, at Rizin 20. He won the fight via knockout in the first round. This was the last fight on the Procházka's contract with Rizin. After the fight, he signed a new deal with the UFC and vacated his title.<ref name="MMAMania2019/12/31">Video: Jiri Prochazka dribbles CB Dollaway with one-punch knockout at RIZIN 20, "MMA Mania" 2019/12/31. Retrieved on 12 July 2020.</ref>


title: Jiří Procházka

text: Procházka signed a contract with the UFC in January 2020. He made his promotional debut against former UFC Light Heavyweight title challenger Volkan Oezdemir on July 11, 2020 at UFC 251. He won via knockout in the second round and was awarded a "Performance of the Night" bonus award.


title: Jiří Procházka

text: Procházka was expected to face two–time UFC Light Heavyweight Championship title challenger Dominick Reyes on February 27, 2021 at UFC Fight Night 186. However, in late January, Reyes was pulled from the fight, due to injury, and the bout was rescheduled for May 1, 2021 at . In a back and forth fight, Procházka won the fight via knockout in the second round. With this win, he was awarded the "Performance of the Night" and "Fight of the Night" bonus awards.


title: Jiří Procházka

text: Procházka was scheduled to face Glover Teixeira for the UFC Light Heavyweight Championship on May 7, 2022 at UFC 274. However, the bout was postponed to June 11, 2022 at UFC 275 for undisclosed reasons. In a back-and-forth fight which saw both fighters get dropped multiple times, Procházka won the bout and title via rear-naked choke submission in the fifth round, becoming the first Czech fighter to win a UFC championship. This fight earned him the "Fight of the Night" award and the Crypto.com ""Fan Bonus of the Night"" award paid in bitcoin of US$20,000 for second place.


title: Jiří Procházka

text: Procházka was booked to rematch Teixeira at UFC 282 on December 10, 2022. However, it was announced on November 23, 2022 that Procházka was forced out of the fight due to an injury to his right shoulder, and that he had vacated the title.


title: Jiří Procházka

text: Procházka is well-known as a devoted follower of the Bushido principles, the samurai moral values and the Miyamoto Musashi's teachings and philosophy, especially the Musashi's "The Book of Five Rings", which Procházka considered as a life-changing book for him.


title: Jiří Procházka

text: He is a supporter of FC Zbrojovka Brno and was involved in organized football hooliganism, including pre-arranged fights, until he started his professional combat sports career.


title: Jiří Procházka

text: Besides his native Czech, Procházka is conversational in English (as of his UFC debut).<ref name="iSportCZ.2020/07/01">Procházka letí na UFC ostrov. Vyladil účes i angličtinu, koho vítal se zbraní?, "iSport.cz" 2020/07/01. Retrieved on 2 September 2020.</ref> While competing in UFC and Rizin FF, Procházka attended Masaryk University for his bachelor’s degree, majoring in security forces physical fitness policy. He is also a graduate of the his local Protective Service Secondary Academy (Czech: SOŠ OOM), now the Brno's School of Law & Security (Czech: BPA).<ref name="Ronnie2013/02/18">Jiří Deniska Procházka: "Hodinovému tréninku se nedá říkat trénink.", "Ronnie CZ" 2013/02/18. Retrieved on 11 July 2020.</ref>


title: Jiří Procházka

text: Procházka is known for his catchphrase, ""BJP"" ("B'e-y'e-p'e"; ). It is the Czech initialism for ""Bomby jak piča(!)"" (English: "Bomb The Shit Out of 'Em[!]" or "Bomb-'em-up[!]"), it is Procházka's battle cry and also the name of his merchandise brand.


title: Jiří Procházka

text: His nickname, Denisa is a girl's name in the Czech language equivalent to the English Denise, and Deniska, It originated during a training camp, where Procházka had responded to his trainer's call for another fighter, who was a girl called Denisa.


title: Jiří Procházka

text: Since 2017, Procházka has lived in a cottage about 30 minutes outside of his hometown of Brno, near a reservoir. The cottage has electricity and other amenities, however it has no gas and he gets his water out of a well.


title: The Band

text: The Band was a Canadian-American rock band formed in Toronto, Ontario, in 1967. It consisted of four Canadians and one American: Rick Danko (bass, guitar, vocals, fiddle), Garth Hudson (organ, keyboards, accordion, saxophone), Richard Manuel (piano, drums, vocals), Robbie Robertson (guitar, songwriting, vocals), and Levon Helm (drums, vocals, mandolin, guitar). The Band combined elements of Americana, folk, rock, jazz, country, and R&B, influencing subsequent and contemporary musicians such as George Harrison, Elton John, the Grateful Dead, Eric Clapton and Wilco.


title: The Band

text: Between 1958 and 1963, the group was known as the Hawks, a backing band for rockabilly singer Ronnie Hawkins. In the mid-1960s, they gained recognition for backing Bob Dylan, and the 1966 concert tour was notable as Dylan's first with an electric band. After leaving Dylan and changing their name to "The Band", they released several records to critical and popular acclaim, including their debut album "Music from Big Pink", in 1968. According to AllMusic, the album's influence on several generations of musicians has been substantial: musician Roger Waters called "Music from Big Pink" the second-most influential record in the history of rock and roll, and music journalist Al Aronowitz called it "country soul ... a sound never heard before". Their most popular songs included "The Weight", "The Night They Drove Old Dixie Down", and “Up on Cripple Creek”.


title: The Band

text: Music critic Bruce Eder described the Band as "one of the most popular and influential rock groups in the world, their music embraced by critics ... as seriously as the music of the Beatles and the Rolling Stones." The Band was inducted into the Canadian Music Hall of Fame in 1989 and the Rock and Roll Hall of Fame in 1994. In 2004, "Rolling Stone" ranked them 50th on its list of the 100 greatest artists of all time, while ranking "The Weight" 41st on its list of the 500 greatest songs of all time. In 2008, the group received the Grammy Lifetime Achievement Award, and in 2014, they were inducted into Canada's Walk of Fame.


title: The Band

text: The members of the Band gradually came together in the Hawks, the backing group for Toronto-based rockabilly singer Ronnie Hawkins: Helm began playing with the group in 1957, then became their fulltime drummer after graduating from high school in 1958. He journeyed with Hawkins from Arkansas to Ontario, where they were joined by Robertson, Danko, Manuel, and finally Hudson. Latter-day Band member Stan Szelest was also in the group at that time. Hawkins's act was popular in and around Toronto and nearby Hamilton, and he had an effective way of eliminating his musical competition: when a promising band appeared, Hawkins would hire their best musicians for his own group; Robertson, Danko, and Manuel came under Hawkins's tutelage this way.


title: The Band

text: While most of the Hawks were eager to join Hawkins's group, getting Hudson to join was a different story. He had earned a college degree, planned on a career as a music teacher, and was interested in playing rock music only as a hobby. The Hawks admired his wild, full-bore organ style and asked him repeatedly to join. Hudson finally agreed, under the condition that the Hawks each pay him $10 per week to be their instructor and purchase a new state-of-the-art Lowrey organ; all music theory questions were directed to Hudson.


title: The Band

text: With Hawkins, they recorded a few singles in this period and became well known as the best rock group in the thriving Toronto music scene. Hawkins regularly convened all-night rehearsals following long club shows, with the result that the young musicians quickly developed great technical prowess on their instruments.


title: The Band

text: In late 1963, the group split from Hawkins over personal differences. They were tired of playing the same songs so often and wanted to perform original material, and they were wary of Hawkins's heavy-handed leadership. He would fine the Hawks if they brought their girlfriends to the clubs (fearing it might reduce the numbers of "available" girls who came to performances) or if they smoked marijuana.


title: The Band

text: Robertson later said, "Eventually, [Hawkins] built us up to the point where we outgrew his music and had to leave. He shot himself in the foot, really, bless his heart, by sharpening us into such a crackerjack band that we had to go on out into the world, because we knew what his vision was for himself, and we were all younger and more ambitious musically."


title: The Band

text: Upon leaving Hawkins, the group was briefly known as the Levon Helm Sextet, with sixth member sax player Jerry Penfound, and then as Levon and the Hawks after Penfound's departure. In 1965, they released a single on Ware Records under the name the Canadian Squires, but they returned as Levon and the Hawks for a recording session for Atco later that year. Also in 1965, Helm and the band met blues singer and harmonica player Sonny Boy Williamson. They wanted to record with him, offering to become his backing band, but Williamson died not long after their meeting.


title: The Band

text: Later in 1965, Bob Dylan hired them for his U.S. tour in 1965 and world tour in 1966. Following the 1966 tour, the group moved with help from Dylan and his manager, Albert Grossman, to Saugerties, New York, where they made the informal 1967 recordings that became "The Basement Tapes", the basis for their 1968 debut album, "Music from Big Pink". Because they were always "the band" to various frontmen and the locals in Woodstock, Helm said the name "the Band" worked well when the group came into its own. The group began performing as the Band in 1968 and went on to release ten studio albums. Dylan continued to collaborate with the Band over the course of their career, including a joint 1974 tour.


title: The Band

text: In late summer 1965, Bob Dylan was looking for a backup band for his first U.S. "electric" tour. Levon and the Hawks were recommended by blues singer John Hammond Jr., who earlier that year had recorded with Helm, Hudson and Robertson on his Vanguard album "So Many Roads". Around the same time, one of their friends from Toronto, Mary Martin, was working as secretary to Dylan's manager, Albert Grossman. She told Dylan to visit the group at Le Coq d'Or Tavern, a club on Yonge Street, in Toronto—though Robertson recollects it was the Friar's Tavern, just down the street. Her advice to Dylan: "You "gotta" see these guys."


title: The Band

text: After hearing the band play and meeting with Robertson, Dylan invited Helm and Robertson to join his backing band. After two concerts backing Dylan, Helm and Robertson told Dylan of their loyalty to their bandmates and told him that they would continue with him only if he hired all of the Hawks. Dylan accepted and invited Levon and the Hawks to tour with him. The group was receptive to the offer, knowing it could give them the wider exposure they craved. They thought of themselves as a tightly rehearsed rock and rhythm and blues group and knew Dylan mostly from his early acoustic folk and protest music. Furthermore, they had little inkling of how internationally popular Dylan had become.


title: The Band

text: With Dylan, the Hawks played a series of concerts from September 1965 through May 1966, billed as Bob Dylan and the Band. The tours were marked by Dylan's reportedly copious use of amphetamines. Some, though not all, of the Hawks joined in the excesses. Most of the concerts were met with heckling and disapproval from folk music purists. Helm was so affected by the negative reception that he left the tour after a little more than one month and sat out the rest of that year's concerts, as well as the world tour in 1966. Helm spent much of this period working on an oil rig in the Gulf of Mexico.


title: The Band

text: During and between tours, Dylan and the Hawks attempted several recording sessions, but with less than satisfying results. Sessions in October and November yielded just one usable single ("Can You Please Crawl Out Your Window?"), and two days of recording in January 1966 for what was intended to be Dylan's next album, "Blonde on Blonde", resulted in "One of Us Must Know (Sooner or Later)", which was released as a single a few weeks later and was subsequently selected for the album. On "One of Us Must Know", Dylan was backed by drummer Bobby Gregg, bassist Danko (or Bill Lee), guitarist Robbie Robertson, pianist Paul Griffin, and Al Kooper (who was more a guitarist than an organist) playing organ. Frustrated by the slow progress in the New York studio, Dylan accepted the suggestion of producer Bob Johnston and moved the recording sessions to Nashville. In Nashville, Robertson's guitar was prominent on the "Blonde on Blonde" recordings, especially "Leopard-Skin Pill-Box Hat", but the other members of the Hawks did not attend the sessions.


title: The Band

text: During the European leg of their 1966 tour, Mickey Jones replaced Sandy Konikoff on drums. Dylan and the Hawks played at the Free Trade Hall in Manchester on May 17, 1966. The gig became legendary when, near the end of Dylan's electric set, an audience member shouted "Judas!" After a pause, Dylan replied, "I don't believe you. You're a liar!" He then turned to the Hawks and said, "Play it fucking loud!" With that, they launched into an acidic version of "Like a Rolling Stone".


title: The Band

text: The Manchester performance was widely bootlegged (and mistakenly placed at the Royal Albert Hall). In a 1971 review for "Creem", critic Dave Marsh wrote, "My response is that crystallization of everything that is rock'n'roll music, at its finest, was to allow my jaw to drop, my body to move, to leap out of the chair ... It is an experience that one desires simply to share, to play over and over again for those he knows thirst for such pleasure. If I speak in an almost worshipful sense about this music, it is not because I have lost perspective, it is precisely because I have found it, within music, yes, that was made five years ago. But it is there and unignorable." When it finally saw in 1998, critic Richie Unterberger declared the record "an important document of rock history."


title: The Band

text: On July 29, 1966, while on a break from touring, Dylan was injured in a motorcycle accident that precipitated his retreat into semi-seclusion in Woodstock, New York. For a while, the Hawks returned to the bar and roadhouse touring circuit, sometimes backing other singers, including a brief stint with Tiny Tim. Dylan invited the Hawks to join him in Woodstock in February 1967, and Danko, Hudson, and Manuel rented a large pink house, which they named "Big Pink", in nearby West Saugerties, New York. The next month (initially without Helm) they commenced recording a much-bootlegged and influential series of demos, initially at Dylan's house in Woodstock and later at Big Pink, which were released partially on LP as "The Basement Tapes" in 1975 and . A track-by-track review of the bootleg was detailed by Jann Wenner in "Rolling Stone", in which the band members were explicitly named and given the collective name "the Crackers". While Helm was not involved in the initial recording, he did perform in later sessions and in overdubs recorded in 1975 before the album's release.


title: The Band

text: The sessions with Dylan ended in October 1967, with Helm having rejoined the group by that time, and the Hawks began writing their own songs at Big Pink. When they went into the recording studio, they still did not have a name for themselves. Stories vary as to the manner in which they ultimately adopted the name "the Band". In "The Last Waltz", Manuel claimed that they wanted to call themselves either "the Honkies" or "the Crackers" (which they used when backing Dylan for a January 1968 concert tribute to Woody Guthrie), but these names were vetoed by their record label; Robertson suggests that during their time with Dylan everyone just referred to them as "the band" and the name stuck. Initially they disliked the moniker, but eventually they grew to like it, thinking it both humble and presumptuous. In 1969, "Rolling Stone" referred to them as "the band from Big Pink".


title: The Band

text: Their first album, "Music from Big Pink" (1968) was widely acclaimed. The album included three songs written or co-written by Dylan ("This Wheel's on Fire", "Tears of Rage", and "I Shall Be Released") as well as "The Weight", the use of which in the film "Easy Rider" would make it one of their best-known songs. While a continuity ran through the music, the style varied by song.


title: The Band

text: In early 1969, after the success of "Music from Big Pink", the Band went on tour, starting with an appearance at Winterland Ballroom. They performed at the Woodstock Festival (their performance was not included in the famed "Woodstock" film because of legal complications), and later that year they performed with Dylan at the UK Isle of Wight Festival (several songs from which were subsequently included on Dylan's "Self Portrait" album). That same year, they left for Los Angeles to record their follow-up, "The Band" (1969). From their rustic appearance on the cover to the songs and arrangements within, the album stood in contrast to other popular music of the day. (Several other artists made similar stylistic moves about the same time, notably Dylan, on "John Wesley Harding", which was written during the "Basement Tapes" sessions, and the Byrds, on "Sweetheart of the Rodeo", which featured two "Basement Tapes" covers.) "The Band" featured songs that evoked old-time rural America, from the Civil War in "The Night They Drove Old Dixie Down" to the unionization of farm workers in "King Harvest (Has Surely Come)".


title: The Band

text: These first two records were produced by John Simon, who was practically a group member: he aided in arrangements in addition to playing occasional piano and tuba. Simon reported that he was often asked about the distinctive horn sections featured so effectively on the first two albums: people wanted to know how they had achieved such memorable sounds. Simon stated that, besides Hudson (an accomplished saxophonist), the others had only rudimentary horn skills, and achieved their sound simply by creatively using their limited technique.


title: The Band

text: "Rolling Stone" lavished praise on the Band in this era, giving them more attention than perhaps any other group in the magazine's history; Greil Marcus's articles contributed to the Band's mystique. The Band was also featured on the cover of "Time" (January 12, 1970), the first rock group after the Beatles, over two years earlier, to achieve this rare distinction. David Attie's unused photographs for this cover—among the very few studio portraits taken during the Band's prime—have only recently been discovered, and were featured in Daniel Roher's Robbie Robertson documentary "", as well as having their own four-page spread in Harvey Kubernik and Ken Kubernik’s “The Story of the Band: From "Big Pink" to "The Last Waltz"” (Sterling Publishing, 2018).


title: The Band

text: A critical and commercial triumph, "The Band", along with works by the Byrds and the Flying Burrito Brothers, established a musical template (sometimes dubbed country rock) that paved the way to the Eagles. Both "Big Pink" and "The Band" also influenced their musical contemporaries. Eric Clapton and George Harrison cited the Band as a major influence on their musical direction in the late 1960s and early 1970s. Clapton later revealed that he wanted to join the group. While he never did join, he recruited all of the members of the Band as well as other roots rock performers for his 1976 album "No Reason to Cry".


title: The Band

text: Following their second album, the Band embarked on their first tour as a lead act. The anxiety of fame was clear, as the group's songs turned to darker themes of fear and alienation: the influence on their next work is self-explanatory. "Stage Fright" (1970) was engineered by musician-engineer-producer Todd Rundgren and recorded on a theatre stage in Woodstock. As with their previous, self-titled record, Robertson was credited with most of the songwriting. Initial critical reaction was good but it was seen as a letdown from the previous two albums for various reasons. After recording "Stage Fright", the Band was among the acts participating in the Festival Express, an all-star rock concert tour of Canada by train that also included Janis Joplin, the Grateful Dead and future Band member Richard Bell (at the time he was a member of Joplin's band). In the concert documentary film, released in 2003, Danko can be seen participating in a drunken jam session with Jerry Garcia, Bob Weir and Joplin while singing "Ain't No More Cane".


title: The Band

text: At about this time, Robertson began exerting greater control over the Band, a point of contention between Helm and Robertson. Helm charges Robertson with authoritarianism and greed, while Robertson suggests his increased efforts in guiding the group were largely because Danko, Helm, and Manuel were becoming more unreliable due to their heroin usage. Robertson insists he did his best to coax Manuel into writing more songs, only to see him descend into addiction.


title: The Band

text: Despite mounting problems among the group members, the Band forged ahead with their next album, "Cahoots" (1971). "Cahoots" featured Bob Dylan's "When I Paint My Masterpiece", "4% Pantomime" (with Van Morrison), and "Life Is a Carnival", the last featuring a horn arrangement by Allen Toussaint. Toussaint's contribution was a critical addition to the Band's next project, and the group would later record two songs written by Toussaint: "Holy Cow" on "Moondog Matinee" and "You See Me" on "Jubilation". In late December 1971, the Band recorded the live album "Rock of Ages", which was released in the summer of 1972. On "Rock of Ages", they were bolstered by the addition of a horn section, with arrangements written by Toussaint. Bob Dylan appeared on stage on New Year's Eve and performed four songs with the group, including a version of "When I Paint My Masterpiece".


title: The Band

text: In 1973, the Band released the covers album "Moondog Matinee". There was no tour in support of the album, which garnered mixed reviews. However on July 28, 1973, they played at the legendary Summer Jam at Watkins Glen, a massive concert that took place at the Grand Prix Raceway outside Watkins Glen, New York. The event, which was attended by over 600,000 music fans, also featured the Grateful Dead and the Allman Brothers Band. It was during this event that discussions began about a possible tour with Bob Dylan, who had moved to Malibu, California, along with Robertson. By late 1973, Danko, Helm, Hudson and Manuel had joined them, and the first order of business was backing Dylan on the album "Planet Waves". The album was released concurrently with their joint 1974 tour, in which they played 40 shows in North America during January and February 1974. Later that year, the live album "Before the Flood" was released, which documents the tour.


title: The Band

text: During this time, the Band brought in "Planet Waves" producer Rob Fraboni to help design a music studio for the group. By 1975, the studio—known as Shangri-La—was completed. That year, the Band recorded and released "Northern Lights – Southern Cross", their first album of all-new material since 1971's "Cahoots". All eight songs were written exclusively by Robertson. Despite comparatively poor record sales, the album is favored by critics and fans alike. Levon Helm regards this album highly in his book, "": "It was the best album we had done since "The Band"." The album also produced more experimentation from Hudson, switching to synthesizers, showcased on "Jupiter Hollow".


title: The Band

text: By the mid-1970s, Robbie Robertson was weary of touring. After "Northern Lights – Southern Cross" failed to meet commercial expectations, much of the group's 1976 tour was confined to theaters and smaller arenas in secondary markets (including the Santa Cruz Civic Auditorium, the Long Island Arena and the Champlain Valley Expo in Essex Junction, Vermont), culminating in an opening slot for the ascendant Z.Z. Top at the Nashville Fairgrounds in September. In early September, Richard Manuel suffered a severe neck injury in a boating accident in Texas, prompting Robertson to urge the Band to retire from live performances after staging a massive "farewell concert" known as "The Last Waltz". Following an October 30 appearance on "Saturday Night Live", the event, including turkey dinner for the audience of 5,000, was held on November 25 (Thanksgiving Day) of 1976 at the Winterland Ballroom in San Francisco, California, and featured a horn section with arrangements by Allen Toussaint and a stellar list of guests, including Canadian artists Joni Mitchell and Neil Young. Two of the guests were fundamental to the Band's existence and growth: Ronnie Hawkins and Bob Dylan. Other guests they admired (and in most cases had worked with before) included Muddy Waters, Dr. John, Van Morrison, Ringo Starr, Eric Clapton, Ron Wood, Bobby Charles, Neil Diamond, and Paul Butterfield. The concert was filmed by Robertson's friend, filmmaker Martin Scorsese.


title: The Band

text: In 1977, the Band released their seventh studio album "Islands", which fulfilled their record contract with Capitol so that a planned "Last Waltz" film and album could be released on the Warner Bros. label. "Islands" contained a mix of originals and covers, and was the last with the Band's original lineup. That same year, the group recorded soundstage performances with country singer Emmylou Harris ("Evangeline") and gospel-soul group the Staple Singers ("The Weight"); Scorsese combined these new performances—as well as interviews he had conducted with the group—with the 1976 concert footage. The resulting concert film–documentary was released in 1978, along with a three-LP soundtrack.


title: The Band

text: Helm later wrote about "The Last Waltz" in his autobiography, "This Wheel's on Fire", in which he made the case that it had been primarily Robbie Robertson's project and that Robertson had forced the Band's breakup on the rest of the group. Robertson offered a different take in a 1986 interview: "I made my big statement. I did the movie, I made a three-record album about it—and if this is only my statement, not theirs, I'll accept that. They're saying, 'Well, that was really his trip, not our trip.' Well, fine. I'll take the best music film that's ever been made, and make it my statement. I don't have any problems with that. None at all."


title: The Band

text: The original quintet would perform together one last time: on March 1, 1978 after the late set of a Rick Danko solo show at The Roxy, the group performed "Stage Fright", "The Shape I'm In", and "The Weight" for an encore. Although the members of the group intended to continue working on studio projects, they drifted apart after the release of "Islands" in March 1977.


title: The Band

text: The Band resumed touring in 1983 without Robertson, who had found success with a solo career and as a Hollywood music producer. As a result of their diminished popularity, they performed in theaters and clubs as headliners and took support slots in larger venues for onetime peers such as the Grateful Dead and Crosby, Stills and Nash.


title: The Band

text: After a performance in Winter Park, Florida, on March 4, 1986, Manuel hanged himself, aged 42, in his motel room. He had suffered for many years from alcoholism and drug addiction and had been clean and sober for several years beginning in 1978 but had begun drinking and using drugs again by 1984. Manuel's position as pianist was filled by old friend Stan Szelest (who died not long after) and then by Richard Bell. Bell had played with Ronnie Hawkins after the departure of the original Hawks, and was best known from his days as a member of Janis Joplin's Full Tilt Boogie Band.


title: The Band

text: The Band was inducted into the Canadian Music Hall of Fame at the 1989 Juno Awards, where Robertson was reunited with original members Danko and Hudson. With Canadian country rock superstars Blue Rodeo as a back-up band, "Music Express" called the 1989 Juno appearance a symbolic "passing of the torch" from the Band to Blue Rodeo.


title: The Band

text: In 1990, Capitol Records began to re-release the records from the 1970s. The remaining three members continued to tour and record albums with a succession of musicians filling Manuel's and Robertson's roles. The Band appeared at Bob Dylan's 30th anniversary concert in New York City in October 1992, where they performed their version of Dylan's "When I Paint My Masterpiece". In 1993, the group released their eighth studio album, "Jericho". Without Robbie Robertson as primary lyricist, much of the songwriting for the album came from outside of the group. Also that year, the Band, along with Ronnie Hawkins, Bob Dylan, and other performers, appeared at U.S. President Bill Clinton's 1993 "Blue Jean Bash" inauguration party.


title: The Band

text: In 1994 the Band performed at Woodstock '94. Later that year Robertson appeared with Danko and Hudson as the Band for the second time since the original group broke up. The occasion was the induction of the Band into the Rock and Roll Hall of Fame. Helm, who had been at odds with Robertson for years over accusations of stolen songwriting credits, did not attend. In February 1996, the Band with the Crickets recorded "Not Fade Away", released on the tribute album "Not Fade Away (Remembering Buddy Holly)". The Band released two more albums after "Jericho": "High on the Hog" (1996) and "Jubilation" (1998), the latter of which included guest appearances by Eric Clapton and John Hiatt. Helm was diagnosed with throat cancer in 1998 and was unable to sing for several years but he eventually regained the use of his voice.


title: The Band

text: In 1998, the group revealed they were working on a follow-up album to "Jubilation" that has not been released.


title: The Band

text: The final song the group recorded together was their 1999 version of Bob Dylan's "One Too Many Mornings", which they contributed to the Dylan tribute album "Tangled Up in Blues". On December 10, 1999, Rick Danko died in his sleep at the age of 55. Following his death, the Band broke up for good. The final configuration of the group included Richard Bell (piano), Randy Ciarlante (drums), and Jim Weider (guitar).


title: The Band

text: In 2002, Robertson bought all other former members' financial interests in the group (with the exception of Helm), giving him major control of the presentation of the group's material, including latter-day compilations. Richard Bell died of multiple myeloma in June 2007.


title: The Band

text: The Band received a Lifetime Achievement Grammy Award on February 9, 2008, but there was no reunion of former members. In honor of the event, Helm held a Midnight Ramble in Woodstock. He continued to perform and released several albums. On April 17, 2012, it was announced via Helm's official website that he was in the "final stages of cancer"; he died two days later.


title: The Band

text: In December 2020, it was announced that the third album of The Band, "Stage Fright", would get an expanded reissue. The album has alternate versions of some songs.


title: The Band

text: In 1977, Rick Danko released his eponymous debut solo album, which featured the other four members of the Band on various tracks. In 1984, Danko joined members of the Byrds, the Flying Burrito Brothers, and others in the huge touring company that made up "The Byrds Twenty-Year Celebration". Several members of the tour performed solo songs to start the show, including Danko, who performed "Mystery Train". Danko also released two collaboraive albums with Eric Andersen and Bjorn Fjeld, along with some live and compilation albums in the 1990s and 2000s; many of the latter records were produced by Aaron L. Hurwitz and are on the Breeze Hill/Woodstock Records Label.


title: The Band

text: In the late 1970s and 1980s, Helm released several solo albums and toured with a band called Levon Helm and the RCO Allstars. He also began an acting career with his role as Loretta Lynn's father in "Coal Miner's Daughter". Helm received praise for his narration and supporting role opposite Sam Shepard in 1983's "The Right Stuff". In 1997, a CD by Levon Helm and the Crowmatix, "Souvenir", was released. Beginning sometime in the 1990s, Helm regularly performed Midnight Ramble concerts at his home and studio in Woodstock, New York, and toured. In 2007 Helm released a new album, an homage to his southern roots called "Dirt Farmer", which was awarded a Grammy Award for Best Traditional Folk Album on February 9, 2008. "Electric Dirt" followed in 2009 and won the inaugural Grammy Award for Best Americana Album. His 2011 live album "Ramble at the Ryman" won in the same category.


title: The Band

text: After he left the Band, Robbie Robertson became a music producer and wrote film soundtracks (including acting as music supervisor for several of Scorsese's films) before beginning a solo career with his Daniel Lanois-produced eponymous album in 1987. He has continued mostly scoring films into the 2010s.


title: The Band

text: Hudson has released two solo CDs, "The Sea to the North" in 2001, produced by Aaron (Professor Louie) Hurwitz, and "Live at the Wolf" in 2005, both featuring his wife, Maud, on vocals. He has also kept busy as an in-demand studio musician. He is featured extensively on recordings of the Call and country-indie star Neko Case. Hudson contributed an original electronic score to an off-Broadway production of "Dragon Slayers", written by Stanley Keyes and directed by Brad Mays in 1986 at the Union Square Theatre in New York, which was restaged with a new cast in Los Angeles in 1990. In 2010, Hudson released "Garth Hudson Presents: A Canadian Celebration of the Band", featuring Canadian artists covering songs that were recorded by the Band.