text:
Baktun

A baktun (properly bʼakʼtun ) is 20 kʼatun cycles of the ancient Maya Long Count Calendar. It contains 144,000 days, equal to 394.26 tropical years. The Classic period of Maya civilization occurred during the 8th and 9th baktuns of the current calendrical cycle. The current baktun started on 13.0.0.0.0 – December 21, 2012 using the GMT correlation.

Archaeologist J. Eric S. Thompson stated that it is erroneous to say that a Long Count date of, for example, 9.15.10.0.0 is in the “9th baktun”, analogous to describing the year 209 AD as in the “2nd century AD”. Even so, the practice is so well established among Maya epigraphers and other students of the Maya, that to change it would cause more harm than its perpetuation. The current practice of referring to the current baktun as ”baktun 13” or “thirteenth baktun” may stand, even though it is properly the fourteenth baktun. Alternatively, the first baktun could instead be referred to as the 0th or null to avoid this ambiguity.

Note
Today,, in the Long Count is (based on the GMT correlation).

title: Baktun


text:
Wyoming Valley

The Wyoming Valley is a historic industrialized region of Northeastern Pennsylvania. The region is historically notable for its influence in helping fuel the American Industrial Revolution with its many anthracite coal-mines. As a metropolitan area, it is known as the Scranton–Wilkes-Barre metropolitan area, after its principal cities, Scranton and Wilkes-Barre. With a population of 567,559 as of the 2020 United States census, it is the fifth-largest metropolitan area in Pennsylvania, after the Delaware Valley, Greater Pittsburgh, the Lehigh Valley, and the Harrisburg–Carlisle metropolitan statistical areas.

Within the geology of Pennsylvania the Wyoming Valley makes up its own unique physiographic province, the Anthracite Valley. Greater Pittston occupies the center of the valley. Scranton is the most populated city in the metropolitan area with a population of 77,114. The city of Scranton grew in population after the 2015 mid-term census while Wilkes-Barre declined in population. Wilkes-Barre remains the second most-populated city in the metropolitan area, while Hazleton is the third most-populated city in the metropolitan area.

The valley is a crescent-shaped depression, a part of the ridge-and-valley or folded  Appalachians. The Susquehanna River occupies the southern part of the valley, which is notable for its deposits of anthracite. These have been extensively mined. Deep mining of anthracite has declined throughout the greater Coal Region, however, due to the greater economics of strip mining. Parts of the local mines had already shut down because some coal beds were on fire and had to be sealed, but the exodus of mining companies came quickly following the legal and political repercussions of the 1959 Knox Mine disaster when the roof of the Knox Coal Company's mine under the Susquehanna River collapsed.

The Pocono Mountains, a ridgeline away, are often visible from higher elevations to the east and to the southeast of the Wyoming Valley.

Early history
The name Wyoming derives from the Lenape Munsee name xwéːwamənk, meaning "at the big river flat."

According to The Jesuit Relations in 1635, the Wyoming Valley was inhabited by the Scahentoarrhonon people, an Iroquoian-speaking group; it was then known as the Scahentowanen Valley. By 1744, it was inhabited by Lenape, Mohican, Shawnee and others who had been pushed out of eastern areas by the Iroquois Confederacy. From the 1740s to the 1760s, the valley was the site of Moravian mission work among the Native Americans living there. They envisioned a settlement for Christian Indians. But the violence of the French and Indian War, known outside the U.S. as part of the Seven Years' War, drove these settlers away with David Zeisberger, the Moravian "Apostle to the Indians."

This led to conflicting claims to the territory by the colonies of Pennsylvania and Connecticut. King Charles II of England granted the land to the Colony of Connecticut in 1662, and then to William Penn in 1681, who established the Province of Pennsylvania, leading to military skirmishes known as the Pennamite–Yankee War. After Yankee settlers from Connecticut founded Wilkes-Barre in 1769, armed bands of Pennsylvanians,, known as Pennamites, tried unsuccessfully to expel them between 1769 and 70, and then again in 1775.

Revolutionary War
During the American Revolutionary War, the Battle of Wyoming took place in the valley on July 3, 1778, in which more than 300 Revolutionaries died at the hands of Loyalists and their Iroquois allies. The incident was depicted by the Scottish poet Thomas Campbell in his 1809 poem Gertrude of Wyoming. At the time, rebel colonists widely believed that Joseph Brant, a Mohawk chief, had led the Iroquois forces; in the poem, Brant is described as the "Monster Brant" because of the atrocities committed. Later colonists determined that Brant had not been present at this conflict. The popularity of the poem may have led to the state of Wyoming later being named after the valley.

Founding of Luzerne County
The Yankee-Pennamite Wars were eventually settled in the 1780s. The disputed land was granted to Pennsylvania. The Wyoming Valley became part of Northumberland County. However, settlers in what was then the Colony of Connecticut wanted to create a new state in Northeastern Pennsylvania. Massachusetts businessman Timothy Pickering was sent to the region to politically examine the situation.

This led the Pennsylvania General Assembly to pass a resolution creating Luzerne County. This ended the idea of creating a new state. On September 25, 1786, Luzerne County was formed from part of Northumberland County. It was named after Chevalier de la Luzerne, a French soldier and diplomat during the 18th century. When it was founded, Luzerne County occupied a large portion of Northeastern Pennsylvania. From 1810 to 1878, it was divided into several smaller counties. The counties of Bradford, Lackawanna, Susquehanna, and Wyoming were all formed from parts of Luzerne County.

Metropolitan statistical area
The Scranton–Wilkes-Barre–Hazleton, PA Metropolitan Statistical Area, also known as the Wyoming Valley, covers Lackawanna, Luzerne, and Wyoming counties. It had a combined population of 558,166 in 2015. The counties adjacent to Wyoming Valley include Monroe County (Southeast), Susquehanna County (Northeast), Wayne County (East), Columbia County (West), Bradford County (Northwest), Carbon County (South), Sullivan County (West) and Schuylkill County (Southwest).

As of the 2000 census, the area also had the highest percentage of non-Hispanic whites of any U.S. metropolitan area with a population over 500,000, with 96.2% of the population stating their race as white alone and not claiming Hispanic ethnicity, however the Hispanic demographic has been significantly rising since then.

When metropolitan areas were first defined in 1950, Scranton and Wilkes-Barre were in separate metropolitan areas. Lackawanna County was defined as the Scranton Standard Metropolitan Area, while Luzerne County was defined as the Wilkes-Barre–Hazleton metropolitan area. The two metropolitan areas were merged after the 1970 census as the Northeast Pennsylvania Standard metropolitan statistical area, with Monroe County added as a component. It was renamed the Scranton–Wilkes-Barre metropolitan statistical area after the 1980 census, and Columbia and Wyoming counties were added. Hazleton was added as a primary city in the 1990 census, while Monroe County lost its metropolitan status.

After the 2000 census, Columbia County lost metropolitan status, while Hazleton was removed as a primary city. Scranton is the largest city in Lackawanna County as well as the entire metropolitan area by a large margin, nearly doubling the population of the second largest city in the metropolitan area, Wilkes Barre.

Physical valley
The physical Wyoming Valley, also referred to as the Anthracite Valley Section, is different from the Wyoming Valley metropolitan statistical area. The physical Wyoming Valley is a canoe-shaped valley, about 25 mi long, which extends from the counties of Susquehanna and Wayne (in the north) to Columbia County (in the south). It includes the cities of Carbondale, Scranton, Pittston, Wilkes-Barre, and Nanticoke. Even though Wyoming County is part of the Wyoming Valley Metropolitan Statistical Area, it is not part of the physical valley.

Culture
Scranton is the cultural center of the Wyoming Valley, being the largest city by population in the metropolitan area.

Sports
The Wyoming Valley also has professional sports teams; they include the Scranton/Wilkes-Barre RailRiders (Minor League Baseball Class AAA), the Wilkes-Barre/Scranton Penguins (American Hockey League), and the Scranton/Wilkes-Barre Steamers (Premier Basketball League). The Wilkes-Barre/Scranton Pioneers were a minor league arena football team in Wilkes-Barre (from 2001 to 2009).

Local attractions
Local attractions include the Mohegan Sun Arena at Casey Plaza in Wilkes-Barre, the Pocono Raceway in Long Pond, PNC Field in Moosic, Mohegan Pennsylvania in Plains, the Toyota Pavilion in Scranton, the Wyoming Valley Mall in Wilkes-Barre, the Shoppes at Montage in Moosic, the Steamtown Mall in Scranton, the Viewmont Mall in Scranton/Dickson City, Pennsylvania, and the Montage Mountain Waterpark/Ski Resort in Scranton. Other historic attractions include Eckley Miners' Village and the Steamtown National Historic Site.

Literature
This area is celebrated in Lydia Sigourney's poem Vale of Wyoming published in her Scenes in my Native Land, 1845, with accompanying descriptive text.

Transportation
The airports for this area are Wilkes-Barre/Scranton International Airport and the Wilkes-Barre Wyoming Valley Airport.

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

title: Wyoming Valley


text:
Frank Nicotero

Frank Joseph Nicotero is an American stand-up comedian, television writer, and television host. He is best known for hosting the game show Street Smarts, which aired in syndication from 2000 to 2005.

Career
Frank Nicotero got his start in Pittsburgh doing stand up, quickly finding success when he landed his first stand-up gig at Pittsburgh's famed Funny Bone comedy club in 1988. Shortly afterward, he toured college circuits, appearing with other comedians including Drew Carey, Adam Sandler, and Rob Schneider—and appearing at more than 300 colleges and clubs throughout the country. He has been a regular for over 10 years at The World Famous Laugh Factory on the Sunset Strip. He is also a regular at The Icehouse in Pasadena and The Comedy Magic Club in Hermosa Beach, California.

In 1996, Nicotero appeared as a contestant on the game shows Debt and Ultimate Fan League, winning over $14,000 cash on the former. This led to him being auditioned by several game show producers to host television pilots, one of which was a bowling game show co-hosted by Pat Sajak. From this, Nicotero also found roles in writing and production for other game shows as well. This included writing for Peer Pressure and Outrageous, in addition to writing and producing Faux Pause on Game Show Network. Nicotero's longest-tenured role was the host of the game show Street Smarts, which aired in syndication from 2000 to 2005.

Nicotero has co-hosted The Sharon Osbourne Show and has appeared as a guest on The Wayne Brady Show, The Rosie O'Donnell Show, FSN's The Sports List, Jury Duty, and the comedy game shows Make Me Laugh and Comedy on the Road. In December 2008, Frank was the voice over announcer for NBC’s Funniest Christmas Moments Special.

In 2011, he hosted a kids show on The Hub called The Game of Life based on the board game. He also was chosen as the second voiceover for TruTV's It Only Hurts When I Laugh, replacing Thom Kikot. In 2012, Frank went on the road with The X Factor as the emcee for all the try-out shows. He was considered as a host for the show. In 2013, he hosted Win, Lose or Pawn, a CMT game show set in a pawn shop. In 2015, he hosted another CMT game show, Pontoon Payday.

Frank’s most recent work is his starring role in the AMC’s streaming service Shudder’s season 2 Christmas Special of Creepshow.

title: Frank Nicotero


text:
Ramón Barros Luco

Ramón Barros Luco (June 9, 1835 – September 20, 1919) was President of Chile between 1910 and 1915.

Barros Luco was born in 1835 in Santiago, Barros Luco was son of Ramón Luis Barros Fernández and Dolores Luco Fernández de Leiva. He graduated from Law School in 1858. He died in Santiago in 1919. He was elected representative for the city of Casablanca in 1861, and from then on occupied a seat in the Lower House, being elected representative for Caldera (1867–70), Curicó (1870–73), Valparaíso (1873–76, and 1888–91), as well as for Santiago, during four separate terms, between 1876 and 1894. Later, he was elected senator for Linares (1900–06).

In his position as President of the House of Deputies in 1891, he endorsed the move to dismiss the then President of the Republic, José Manuel Balmaceda, a move drawn up by the Congress. In addition, he lent his support to the uprising of the National Army, whose movements he oversaw, (alongside Waldo Silva, vice-president of the Senate), until they took their place in the government in Iquique. The revolution having succeeded, he resumed his functions as a parliamentarian, performing as a minister on several occasions, whenever the situation called for, "someone who posed no threat to anybody".

In 1910, given the existing tensions between liberals and nationals in the debate over a common candidate, he was chosen as the representative for both parties. His career to date assured both parties that, if he were to be elected, their interests would remain unharmed.

Government
The philosophy of Barros Luco's government can be summarised with the following phrase, well known in Chile, "99% of problems solve themselves, and the remaining 1% have no solution" ("El 99% de los problemas se resuelven solos y el 1% restante no tiene solución"). He applied this maxim to his administration, which would be consumed by the machinations of the parliament at large, the propensity of which was to delay or hinder the government under any pretense, including the most trivial claim of a minor deputy. However, Barros Luco cannot be accused of mere acceptance and reluctance to act, as he possessed a plan to counter the aforementioned political strategy of accusations and delays, and subsequent frequent change of ministers, known as the "rotativa". His policy was as follows: anytime a deputy placed an accusation against a minister leading to said minister's downfall, the accusing deputy would be called upon to head the new cabinet. His hopes were dashed however, as this "rotary" system arrived at a total of 15 ministers, the first of whom lasted only 18 days in office, and the last of whom failed even to appear before Congress, the previous minister having resigned only days before the handover of government.

Some deputies, led by the liberal Manuel Rivas Vicuña, tried to correct the parliamentary vices, with the support of Pres. Barros Luco. In 1912 he approved a modification to the system of parliamentary debate (in particular the system to finish debates), however if a large enough group opposed a motion or accused a minister, parliament could still be severely delayed.

Meanwhile, the corruption amongst the political parties had reached alarming levels, in answer to which laws against fraud were approved in 1914 and 1915, in addition to a reform of the municipal system, which managed to eliminate the falsification of results, allowing for greater transparency. However this reform brought with it an unexpected negative side effect: an increase in electoral bribery.

Barros Luco also focused his efforts on public works; during his term of office he initiated the construction of the port of San Antonio, in addition to the construction of roads, bridges, drinking water and sewers.

Also, the national School of Engineering, Museum of History, National Archives, School of Aviation and the Arica-La Paz railway were built during his tenure as president. However, the large majority of works during his time represented the completion of projects begun by Pedro Montt Montt, fulfilling a promise of Montt's, "like the tale of a child with an egg. Another started the work, and no one will know in the end to whom the credit is due. They will end up by paying graditude to the one who has had the least to do with the project" (Pres. Montt was reputed to have complained thus as he laid the cornerstone of the National Library of Chile).

Foreign policy
On the international scene, on 25 May 1915, he signed the ABC Pact. This pact, signed between the so-called "ABC Powers" (Argentina, Brazil and Chile), was a means to combat the influence of the United States in the region, as well as to establish an equilibrium and channels of communication between the three signatories. The official name of the pact was the Non-Aggression, Consultation and Arbitration pact.

During his government the First World War broke out, with Chile adopting a neutral position. While this position would bring initial economic benefits, in the long term the consequences were dire; although the price of salitre (sodium nitrate) had risen due to European demand, the limitation of salitre exports to Germany would mean that, apart from losing a valuable market, Chile would also lose their natural monopoly as a result of the development of synthetic salitre. This would spell the beginning of the end of the salitre industry in Chile.

Namesake sandwich
Barros Luco used to eat a particular sandwich often, which became known as a Barros Luco. The sandwich is made with a slab of steak or multiple slices of beef with melted cheese, prepared on the grill and served hot. It is available today in most restaurants throughout Chile.

title: Ramón Barros Luco


text:
Talk:Magnetohydrodynamics

Annotation / Description of figures
Would be great if these could be extended. For instance, in the Waves section, there are diagrams of v_Fast, v_Slow and v_Shear - I suspect that these correspond to the three types of waves in the table but it's not clear which is which, or even if that is indeed the case. As it's not my area I can only kindly ask for someone from the field to improve the description / annotation of the figures. 80.109.126.25 (talk) 12:43, 19 December 2017 (UTC)dpk

 * There is in fact a typo in the legends of those two figures. The legend entries for v_Slow and v_Shear (the pure oblique Alfven wave) should be swapped. The phase velocity of the slow wave is always less than the Alfven wave. See https://www2.mps.mpg.de/solar-system-school/lectures/space_plasma_physics_2007/Lecture_7.pdf for example OpenEyeSignal (talk) 04:41, 17 May 2023 (UTC)

Limits of MHD
"MHD is lacking when electric currents flows through these plasmas and produces filaments, double layers and plasma instabilities."

Aren't filaments essentially a product of the pinch effect, which is MHD? And there are certainly many fluid instabilities. You might be right about double layers. Can you (Iantresman) tell me in three sentences how they form? Art Carlson 06:20, 2005 Jun 8 (UTC)

 * I removed the offending sentence. Electric current flowing through plasmas, and the formation of "filaments ... and plasma instabilities" are explicitly part of magnetohydrodynamics.  The formation of a double layer is an example of breakdown of MHD, but I don't believe that they are actually observed.  zowie 19:24, 16 October 2005 (UTC)

 * I'm not sure I understand your reasoning. (1) What is "explicitly part of magnetohydrodynamics"? (2) If the formation of a double layer is an example of breakdown of MHD, then why can't we say so, as an example? (3) Likewise, aren't field-aligned currents a breakdown of MHD, in which case, why don't we say so. (4) You say that "don't believe that they are actually observed"... do you mean that double layers are not observed, and if so, where? --Iantresman 20:52, 16 October 2005 (UTC)

 * (1) Electrical currents of all types are allowed in magnetohydrodynamics. That is the whole and entire point of MHD - to deal with the coupling of Maxwell's Equations governing electrical phenomena and the Navier-Stokes Equations governing fluid dynamics.  Filament formation and the various instabilities are well known magnetohydrodynamic phenomena; they are predicted by the MHD equations and hence are not examples of the breakdown of the theory.

 * (2) My bad - transient double layers are worth a mention, especially in the context of magnetic reconnection or electrojet formation.  Sorry if I threw out a baby with that particular bathwater.  (also, see (4) below).

 * (3) In the special case of quasi-static, low-beta plasmas (in which all non-magnetic forces are negligible) only field-aligned currents are allowed -- but in high-beta plasmas (in which the plasma gas pressure dominates over the magnetic pressure) non-field-aligned currents are also allowed.  The important effect here is the Lorenz force, which is proportional to J x B (where J is the electric current and B is the magnetic field).  In quasi-static, low-beta plasmas, J x B must be near zero everywhere, which means that J (if it exists) must be nearly parallel to B -- ie field-aligned. In other systems, the JxB force can be balanced by inertial forces ('mass times acceleration'; non-static) or by other forces (such as a gas pressure gradient or gravity; non-low-beta).

 * (4) Hmmm... When I typed that I was thinking of non-transient resistive regions in a plasma; but I had a look at some of the review articles in the double layer article (I think you may have linked to them; thanks!), and my mind is changed.  I'm used to thinking of double layers as transient phenomena, perhaps related to anomalous resistivity in magnetic reconnection -- but I was surprised to read that relatively stable double layers can form in lab plasmas and are thought (by at least some) to form in astrophysical plasmas as well.  So, I stand corrected here.  Thanks!

 * Cheers, zowie 00:51, 17 October 2005 (UTC)

 * Is there a contradiction between (1) you say "Electrical currents of all types are allowed in magnetohydrodynamics.", but then in (3) ".. in low-beta plasmas .. only field-aligned currents are allowed". Does this imply that non-field-aligned currents are not allowed in low-beta plasmas, or not described. And if such currents are found, is that a breakdown?

 * Non-field-aligned currents are simply not force-free; they violate a particular further simplification of MHD. Hmmm...  A good analogy: parasitic capacitance violates the assumptions of basic circuit design, because normally one assumes that the circuit traces are perfectly isolated.  That doesn't mean Maxwell's Equations are wrong -- just that you can't use that particular simplifying assumption. zowie 15:11, 17 October 2005 (UTC)

 * I get the impression from Alfvén that certain currents in certain plasmas, do result in a breakdown of MHD?

 * The usual MHD equations predict the behavior of the fluid plasma for all finite configurations of electric current. Ideal MHD predicts the formation of  ideal current sheets, which are not physical (ideal current sheets are infinitely thin and carry an infinite current density); but they are only singularities of the first kind (integrating across them gives a finite amount of current).  Non-ideal MHD does not suffer from that problem, because the plasma resistivity limits the thickness of the sheet.

 * And that the electric field across a double layer resulting in beams and jets (electric currents?) are also a breakdown?

 * One normally assumes that the electric field is zero everywhere (ideal) or near-zero everywhere (non-ideal); double layers are not well described by the normal MHD equations. Of course one may augment them with some kind of anomalous resistivity term that describes double layer formation -- but that is outside the normal theory.

 * Do you have access to Alfvén's Cosmic Plasmas (1981)? --Iantresman 13:41, 17 October 2005 (UTC)

 * I do not have it in my office.  I generally work with Priest's books ("Solar MHD" and "Magnetic reconnection").

 * I'll post (here in the discussion) what I mean by "the usual MHD equations" -- but I want to make sure I have a reference handy, so I don't muck it up by doing it from memory. That way at least we won't be talking past each other. zowie 15:11, 17 October 2005 (UTC)

 * Since double layers may generate quite large electric fields, (up to 10^4V in the auroral electrojets), can we say that MHD breaks down when significant non-field aligned electric currents are generated, for example, in in some double layers (ie. oblique double layers)? --Iantresman 15:55, 17 October 2005 (UTC)

 * The MHD equations are (from Priest's _Magnetic_Reconnection_):

 * Mass conservation:

 * $$\frac{d\rho}{dt}=\frac{\partial\rho}{\partial t} + v\cdot y\nabla\rho = -\rho\nabla\cdot v$$ (where $$\rho$$ is the density and $$v$$ is the plasma velocity)

 * Momentum conservation:

 * $$\rho\frac{dv}{dt} = -\nabla p+ j\times B + \nabla\cdot S + F_g$$ (where $$p$$ the normal gas pressure, $$j$$ is electric current, $$S$$ is the viscous stress tensor [so $$\nabla\cdot S$$ is itself a vector], and $$F_g$$ is any externally applied volume force such as gravity) This is very similar to the Navier-Stokes momentum equation for fluids, (which itself is a fancy way of writing "ma=F"), except that it includes the Lorenz force $$j\times B$$ as one of the force terms.

 * Internal energy conservation:

 * $$\rho\frac{de}{dt} + p\nabla\cdot v = \nabla\cdot(\kappa\cdot\nabla T) + (\eta_e\cdot j)\cdot j + Q_v - Q_r$$ (where $$e$$ is the internal energy per unit mass [something like temperature over the molecular mass], $$\kappa$$ is the thermal conductivity tensor [indicating direction and strength of thermal flux, given a direction and strength of thermal gradient], $$\eta_e$$ is the electrical resistivity tensor [direction and strength of the electric field given a direction and strength of current flow], and $$Q_v$$ and $$Q_r$$ are the viscous (friction) heating and radiative loss terms, respectively).

 * Faraday's Law:

 * $$\nabla\times E = -\frac{\partial B}{\partial t}$$ (this is the electric induction equation)

 * Ampere's Law:

 * $$\nabla\times B = \mu j$$ (here, $$\mu$$ is the permeability of free space; it depends on the system of units you like)

 * Gauss's Law:

 * $$\nabla\cdot B = 0$$ (no magnetic monopoles)

 * Ohm's Law:

 * $$E = \eta_e\cdot j - v\times B$$ (Neglecting $$\eta_e$$ is what yields reconnection-free "ideal MHD")

 * Equation of State (ideal gas law)

 * $$p = \rho \frac{k_B}{\mu_{av}} T$$ (this is just the familiar PV = nRT, rewritten -- $$\mu_{av}$$ is the average particle mass in the plasma, not to be confused with $$\mu$$, the permeability of free space!)

It's usually more convenient to combine Faraday's Law, Ampere's Law, and Ohm's Law to eliminate the $$j$$ and $$E$$ terms -- then you get the magnetic induction equation:

 * $$\frac{\partial B}{\partial t} = \nabla \times (v \times B) - \nabla \times ( (\frac{\eta_e}{\mu}) \nabla \times B)$$, which describes time evolution of the magnetic field in terms only of the velocity field and the resistivity. This makes it obvious why "ideal MHD" is so "ideal": turning off the resistivity completely eliminates one of two reasons why the magnetic field can change.  The left-hand term describes the magnetic field being carried around by bulk motion; the right-hand term describes the decay of the magnetic field.  Incidentally, keeping the $$\eta_e$$ inside that first curl operator is important for the physics you're interested  in -- double-layer formation.

 * If the resistivity is constant across the whole plasma, then $$\eta_e$$ is just a constant and the right hand side gets even more simple -- $$\nabla\times\nabla\times B$$ is just $$\nabla^2B$$, and you get the old, familiar RHS of the diffusion equation.  That diffusion term is what prevents the formation of current sheet singularities in resistive MHD: in an very thin current sheet, $$\nabla^2B$$, would be very large so $$\frac{\partial B}{\partial t}$$ would also be very large -- in the corrective direction.

 * If the resistivity varies in space, you can't commute it through the outer $$\nabla$$, so you get additional terms that describe evolution of the magnetic field near an anomalously resistive area (such as a double layer or condensed region or whatever). The equations above can't predict that change in resistivity -- that is external to the system of equations.  In that sense, the system "fails" near double layers: you have to put in more information about the resistivity of the plasma that isn't present in the original equations.

Anyway, the upshot of all of this stuff is that the physical equations don't fail simply because resistivity varies or there are field-aligned electric fields or whatever. Some idealizations may fail, but the fluid approach (informed by the underlyling particle kinematics) remains sound. I suppose it would be useful to list explicitly the assumptions most people use when working in this field ("assumptions of MHD") but I'm all out of steam for now. zowie 17:57, 17 October 2005 (UTC)

 * Thanks for all that, very impressive. Have you thought about transferring it to the MHD page proper? I can certainly recomend Alfvén's Cosmic Plasmas. As the man who devloped MHD, he will explain far better than I can, some of the points I am trying to convey, and you'd understand it far better than I can. His other book, co-authored with Carl-Gunne Fälthammar is Cosmical Electrodynamics (2nd Ed. 1963) is also recommended. --Iantresman 23:29, 17 October 2005 (UTC)

 * Well, not so impressive maybe -- but plenty tedious, which is why most folks prefer to wave their hands under simplifying assumptions! :-) You're probably right -- the equations and usual assumptions should be present.  But I won't have time to look at it again for a few more days.  Anyone else want to see this stuff in the article itself?  zowie 23:58, 17 October 2005 (UTC)

 * There is a good reason that MHD is commonly treated with suspicion: it is often applied to plasmas where the assumptions of a locally thermal plasma do not hold. In particular, fusion, space and astrophysical plasmas are often so collisionless that the collisions can be ignored, and there is no reason for the plasma to be thermal. The question is usually not whether MHD can rigourously be applied (it cannot) but whether it still describes the qualitative physics, and approximates the quantitative physics (MHD is still usually pretty useful). For example, field aligned electric fields arise in collisionless plasmas due to kinetic effects, and it is usually difficult to even get the large scale physics correct with a fluid model (the Aurora is a case in point). Even large scale structures like the Earth's bow shock are only approximately resolved by MHD. Beams in collisionless plasmas can add a fair amount of pressure and move things around. But on the other hand, (fast) magnetic reconnection is now believed to be well modelled by Hall MHD (as long as you are interested in overall shape and timescales and not the details of particle acceleration).
 * So there probably needs to be a section on where MHD is valid, and why MHD is still useful even when not strictly valid.--Dashpool 17:09, 19 May 2006 (UTC)

 * Hmm, Dashpool -- do you have a good reference on Hall MHD and astrophysical magnetic reconnection? At least in the solar physics community I hear no clear consensus on how reconnection proceeds.  People talk of anomalous resistivity and possible accelerating mechanisms to make the jump from Sweet-Parker type reconnection to faster modes like Petschek reconnection, but there's still an ongoing debate over things like why the energy scaling law appears linear in magnetic field strength (rather than quadratic).  Pevtsov et al (2001?) observed the linear scaling law over a huge number of orders of magnitude -- something like 12 orders of magnitude in total magnetic flux, in astrophysical systems from solar bright points to quasars.  Schrijver et al (2004?) did an interesting study where they examined forward models of coronal plasmas and tried to match the morphology of the observed corona.  Longcope (several references over the last few years) seems to think, like me, that most of the energy is released NOT near the reconnection site but farther away.  I've been modeling solar MHD systems using a simple ad-hoc anomalous resistivity that turns on when the current density gets too high -- but I don't think that anyone (yet) has a clear and unambiguous understanding of why and when such a resistivity should happen. zowie 15:24, 22 May 2006 (UTC)

 * You've probably already seen it, but can I suggest: Hall effects on magnetic relaxation, Turner, Leaf, IEEE Transactions on Plasma Science (ISSN 0093-3813), vol. PS-14, Dec. 1986, p. 849-857. --Iantresman 17:57, 22 May 2006 (UTC)

 * Probably I need to add some caveats and reduce the force of the statement I made earlier: even if I think an answer is emerging, there is still substantial controversy about reconnection mechanisms, and probably wikipedia isn't the place for picking a winner. Shay+Drake JGR 2001 is a good example of the school of thought I'm thinking about wrt Hall reconnection. I'm not sure that the energy scaling law you mentioned conclusively rules out fluid models of reconnection: Pevstov even mentions in his conclusion that he thinks models involving heating via Alfvén modes (mostly just MHD physics) might explain the power law dependence. Why do you think this scaling rules out reconnection models based on the Hall effect? I'm not sure that Hall MHD is inconsistent with energy release 'far from the reconnection region' either: geometrical effects are important. Also, the question is whether Hall MHD predicts global structures/timescales, rather than details. I think the best information on reconnection comes from plasmas which are well characterised, with in-situ measurements, and for these plasmas there is strong evidence for Hall MHD scaling. For example, the MRX (magnetic reconnection experiment) people presented results at the ICPP conference last week showing very good agreement with timescales expected from Hall MHD. Measurements from WIND in the magnetotail support the existence of quadrupole fields expected in Hall MHD reconnection (Oieroset, Nature 412, p414, 2001). The question of why and when anomalous resistivity arises is avoided in Hall MHD, because the (global) physics becomes insensitive to the resistivity mechanism. My view is that that reconnection in relatively simple scenarios is becoming fairly well understood, and that the problem is to understand the complex systems: but a Hall MHD simulation of a decent chunk of the corona would be difficult, and I don't know of any references on Hall MHD for solar plasmas. From the point of view of writing the article, maybe we could say "resistive MHD simulations usually find rates of reconnection far lower than those observed in systems with low collisionality, but there is evidence that the two-fluid MHD model can predict the rate of magnetic reconnection in many of these systems.". --Dashpool 16:39, 28 May 2006 (UTC)
 * that wording sounds fine to me. Thanks very much for the Shay & Drake reference (And thanks, Ian, for the Leaf reference as well).  To clarify, I can't really opine over the role of the Hall effect on reconnection rates, since I haven't thought much about it -- I just wanted to find a place where I could read more about the physics...  Kind regards, zowie 17:21, 28 May 2006 (UTC)
 * I have reorganised the Ideal MHD section to try to make it more logical and explain the various limitations clearly, and separate out the ideas about current sheets. Dashpool 14:56, 9 July 2006 (UTC) I have removed some material (the writeup on infinitely thin current sheets seemed spurious), and removed some of the references to individual physicists. We just need to explain the physics here, rather than the (in fact, uncontroversial) viewpoints of individuals.Dashpool 15:19, 9 July 2006 (UTC)

Voltage at Waterloo Bridge in trivia
Would someone do this calculation? I did it about forty years ago at school and remember the answer as one volt, but when I do it now I get a couple of orders of magnitude less. However I am now rusty on these things and they have changed to SI units, so someone should recheck my calculation. Assume that the water is flowing at one metre per second and the river is 200 metres wide. In London the earth’s magnetic field is 55,000 nanotesla and the dip angle is 67 degrees (it is zero at the equator and 90 degrees at the magnetic poles). You then have to invoke Fleming's right hand contortion to get the direction. JMcC 11:07, 20 June 2006 (UTC)

Also, how could Wollaston do this measurement when he had (according to his main article) already been dead for more than two decades? --83.233.10.87 (talk) 20:38, 23 September 2009 (UTC)

he must've been a very persistent researcher! Bob Emmett (talk) 05:35, 21 March 2010 (UTC)

Magnetohydrodynamics, Electrohydrodynamics, and Electrokinetics
What's the difference? — Omegatron 20:22, 26 June 2006 (UTC)

To get things going:

 * "In more precise terms, EHD is the study of fluid flow behavior under the influence of electric fields. Electrohydrodynamics is, in essence, the mirror of electrokinetics, which is concerned with the thrust effect generated by these non-conducting media on the electric field generating apparatuses. As expected, the terms electrohydrodynamics and electrokinetics can be easily interchanged depending on the aspect used to describe the same system. For convenience, this section contains information concerning the hydrodynamic aspect of the apparatuses."
 * "Electrohydrodynamics deals with fluid motion induced by electric fields."
 * "Electrokinetics involves study of motion of liquid or particles under the action of electric field."
 * "Magnetohydrodynamics (MHD). This is the theory of the macroscopic interaction of electrically conducting fluids with a magnetic field."
 * "Magnetohydrodynamics (or MHD for short) is the study of the interaction between a magnetic field and a plasma treated as a continuous medium" ]
 * "[magnetohydrodynamics], study of the motions of electrically conducting fluids and their interactions with magnetic fields."

Ok, nevermind about MHD. I see the difference now. EHD and electrokinetics are not clear though. — Omegatron 23:29, 26 June 2006 (UTC)

 * I don't forget gravitoelectrodynamics --Iantresman 23:46, 26 June 2006 (UTC)
 * That's not really related. These three are all involved with electrically conducting fluids. — Omegatron 23:56, 26 June 2006 (UTC)

Image on the MHD page
I think a picture without a scale and a legend (what is plotted?) is really not something that should be on wikipedia USferdinand 21:38, 16 January 2007 (UTC)

Ideal MHD equations
I think a form of the ideal MHD equations should be on the MHD page. The references to the single equation pages is confusing. In fact, the momentum equation page does not have the differential equation, and the Ampere's Law page only refers to the integrated form of the equation. I am fine with the Priest equations even though I prefer the divergenceless form of the MHD equations.

$$ {\partial \rho \over \partial t} + \nabla \cdot (\rho \mathbf{u}) = 0$$

$$ {\partial \rho \mathbf{u} \over \partial t} + \nabla \cdot (\rho \mathbf{u} \mathbf{u} + (p +{B^2 \over 8 \pi} )\mathbf{I} - {\mathbf{B}\mathbf{B} \over 4 \pi}) = \mathbf{F}$$

$$ {\partial \mathbf{B} \over \partial t} + \nabla \cdot (\mathbf{u} \mathbf{B}-\mathbf{B}\mathbf{u}) = 0$$

where $$ \rho $$ is density, t is time, B is the magnetic field, u is fluid velocity, and F is the forces by unit volume (such as $$ \rho \mathbf{g} $$ for the gravity).

Also a reference to the divergenceless nature of B should be added. A entry on numerical MHD (8-wave formulation) is, in my opinion, needed. USferdinand 21:54, 16 January 2007 (UTC)

Comment from another person: I concur that these equations should be on the MHD page. Also, the third equation above is commonly referred to as "the induction equation", not Ampere's Law; it is derived from Faraday's Law. Ampere's Law does not specify the time dependence of the magnetic field in terms of the other variables, which is necessary to describe the evolution of the full system. --Brianwelsch (talk) 02:55, 14 May 2010 (UTC)

I agree that these equations should be on this page as well. Preferably in SI units, and I'd suggest an adiabatic equation of state (no thermal conduction). Freidberg's Ideal MHD book has them in the appropriate forms. I would say also that avoiding dyadic tensors as much as possible is probably best since the conventions among plasma physicists aren't always used in other fields. Maybe I'll put them up, one of these months. Spacehippy (talk) 05:22, 25 March 2011 (UTC)

I just added the ideal MHD equations from Ideal Magnetohydrodynamics by Jeffrey P. Freidberg. The style and explanation are not quite there yet, so some expansion and revisions are still needed. I should be able to come back to this soon. Spacehippy (talk) 23:08, 25 March 2011 (UTC)

I would like to list the equations all together in a (1) ... (6) style (compare german wiki). Any objections? Skangaroo (talk) 14:48, 27 April 2015 (UTC)

Question about the text at Hall MHD
I looked through the page and I found the following statement at Hall MHD which I could not really understand: The most important difference is that in the absence of field line breaking, the magnetic field is tied to the electrons and not to the bulk fluid. I guess someone either wanted to talk about reconnection ("breaking" of field lines) or is talking about the slowing down ("braking" of the field lines). Anyway, can the person who wrote this make a better statement? Tusenfem (talk) 18:21, 5 February 2009 (UTC)

Two-fluid MHD and Hall MHD are actually very similar, and the terms are sometimes used interchangeably. Extended MHD and collisionless MHD are also related to each other and Two-fluid/Hall MHD. A few of these sections should probably be combined. Spacehippy (talk) 05:27, 25 March 2011 (UTC)

Busted references
Hi, I just noticed footnote number 7 has linkrotted. Not sure what the original paper was being referenced. —Preceding unsigned comment added by 76.118.178.33 (talk) 01:32, 1 December 2009 (UTC)
 * Fixed it. --Art Carlson (talk) 09:48, 1 December 2009 (UTC)

What's the point of Fig. 1?
It is beautiful, but neither cited nor described. Also I suspect it is fundamentally irrelevant as a tutorial guide, since it is an MHD simulation of a collisionless plasma. Maybe such a thing is useful in some practical sense, but it would be wrong to give the impression that such a plasma should be approached in this manner as a matter of principle. —Preceding unsigned comment added by Hugh Hudson (talk • contribs) 13:49, 21 April 2010 (UTC)

I was planning to rearrange some stuff
- The history section needs to go near the top. It will improve the flow of the article. - I was planning to make some additions to the geophysics section.

Please let me know if the changes are alright. I will check back soon. ShashankSawant (talk) 16:55, 23 April 2011 (UTC)

MAGNETO-HYDRO-DYNAMIC (MHD) POWER GENERATION

1	INTRODUCTION In magneto hydrodynamic power generation heat directly covered into electrical energy. The basic principle of MHD generation is the same as that of conventional electrical generator i.e. the motion of a conductor through a magnetic field induces an e.m.f. in it. In steam power plant the heat released by the fuel is converted into mechanical energy by means of a thermo-cycle and mechanical energy is then used to derive the electric generator. Thus two stages of energy conversion are involved in which the heat to mechanical energy conversion has inherently very low efficiency. Also, the rotating machine has its associated losses and maintenance problem. In MHD generation, electrical energy is directly generated from hot combustion gases produced by the combustion of the fuel without moving parts.MHD generator is a heat engine operating on a turbine cycle and transforming the internal energy of gas directly into electrical energy. So an MHD generator is a device for converting heat energy of a fuel directly into electrical energy without a conventional electric generator. In an MHD generator, electrically conducting gas at a very high temperature is passed at high velocity through a strong magnetic field at right angles to the direction of flow, thereby generating electrical energy. The energy is then collected from stationary electrodes placed on the opposite sides of channel as shown in Fig.1. . The current so obtained is direct is direct current dc which can be converted into a.c. by using an inverter. Figure 1 In this method ionized gas is produced by heating the gas to a high temperature. On heating of a gas, the outer electrons escape out from its atoms or molecules. The particles acquire an electric charge and the gases passes into the state of plasma. However, to achieve thermal ionization of products of combustion of fossil fuel  inert   gases, extremely high temperatures are necessary. Air becomes highly ionized at temperature of 5000oC. To have a reasonable value of electrical conductivity of gases at temperature around 2000oK to 3000oK by reasonable ionization, the gases are seeded with additives of easily ionizing materials (alkali metals) such as cesium or potassium.

2   WORKING PRINCIPLE OF MHD POWER GENERATION In MHD power generation conversion process depends upon Faraday’s low of electromagnetic induction, which states that when a conductor and a magnetic field move relative to each other, a voltage is induced in the conductor. This induced voltage produces an electric current. The conductor may be solid, liquid or gas. In MHD generator solid conductors are replaced by hot ionized gas. The hot ionized gas (3000oC) is passed through the MHD duct across which a strong magnetic field is applied. Since the gases are hot and ionized they form an electrically conducting medium moving in a magnetic field, thus a voltage is generated. The power generated by MHD generator is in the direct current form. Now if the electrodes are placed in a suitable position then generated current can be extracted. Figure 2 Consider a particle, having a charge q moving towards right with velocity v, and a perpendicular magnetic field with flux density B is applied. A magnetic force F acts on the charged particle and given by                  =q ( x )                                                                                ……. (1.1)	Now, particle is replaced by ionized gas molecules, moving with velocity V, the positive ions would be accelerated towards plate P1 and negative ions would be accelerated towards plate P2. If the plates are connected through a resistance a current would flow through resistance. Thus, mechanical energy is converted into electrical energy. If an electric field E is also present then equation (1.1) becomes = q {( + ) x }                                                                              …. (1.2)

In MHD generator, the velocity  is the vector sum of gas velocity V are particle drift velocity u.  Therefore,  =  + Then	 = q (E + x    +  x )                                                                           .... (1.3)	Let E +  x  =E’ then = q (E’+ x )                                                                                …….. (1.4)                                                 Figure 3

Consider the Fig .2 the movement of gas in x direction, magnetic field B is in y direction and force on the particle in z direction. When the current I is flowing through load resistance RL, then electric intensity between the plates is = -                                                                                ……. (1.5) Where V is the voltage across load RL and‘d’ is the distance between the plates. Total electric field ’Z =  Z +B ’Z = -   +  V ’Z =  (BVd – V)                                                ……. (1.6)

The electromagnetic field EZ and B acting on the moving gas produce the same force on the ions as the electromagnetic field  E’Z  and B produce on a gas with zero average velocity. Open circuit voltage EO=BVd                                                         …….. (1.7)	If Rg is the internal resistance of the generator, then maximum power output is obtained when Rg= R¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬L P = E0I =IR¬g  I= I2Rg                                                                                …..(1.8)

I = P=       Rg

Put     Rg =  RL then Pmax  =                                                                                …..(1.9)

Also, Rg =                                                                                …..(1.10) Where:   σ=     Conductivity of gas A=      Area of the plate

Then from equation (1.7) and (1.10) Pmax	=                       ...…. (1.11)

Maximum power per unit volume =                                …… (1.12) Also, put the value of Eo from equation (1.7) in (1.9)

Pmax =                                                                                …... (1.13)

MHD system is reversible process. If instead of resistance an emf greater that Eo is applied (when the switch is at position 1) in opposite to the direction of the flow of above current, energy would be supplied to the gas, the particles of the gas would be accelerated. So, the rejected gas is at a higher velocity than the inlet gas. The reaction forces push the MHD engine in negative x direction. Now the electrical energy is converted into mechanical energy 3   MHD SYSTEMS Magneto hydrodynamic conversion systems can operate in either open or closed cycles. In an open cycle system, the working fluid is used on the once through basis. The working fluid after generating electrical energy is discharged to the atmosphere through a stack. In the closed cycle, system the working fluid is continuously recalculated; however,  the discharged working fluid is reheated and returned to the converter. In an open cycle system the working fluid is air. In closed cycle systems helium or argon is used as the working fluid. In open-cycle systems, the hot combustion gases offer seeding can be used directly as the working fluid, in closed cycle system helium or argon is used as the working fluid. In open-cycle systems, the hot combustion gases offer seeding, can be used directly as the working fluid, in closed cycle systems, however, heat is transferred from the combustion gases to the working fluid by means of a heat exchanger. A higher working temperature and a better thermal efficiency are thus possible in open cycles, provided suitable construction materials are available Thus the MHD systems can be classified broadly as follows:- 1)	   Open cycle systems. 2)	     Closed cycle systems. This may be further sub classified as : (i)	 Seeded inert gas systems, and (ii)	Liquid metal systems These are described in the following sections. 3.1	OPEN-CYCLE SYSTEMS The arrangement of the systems is shown schematically in Fig (3). In this system, fuel used may be oil through an oil tank or gasified coal through a coal   gasification plant. The hot gases from combustor is ten seeded with a small amount of an ionized alkali metal (cesium or potassium), to increase the electrical conductivity of the gas. The seed material, generally potassium carbonate, is injected into the combustion chamber; the potassium is then ionized by the hot combustion gases at temperatures of roughly (2300 to 27000 C)  To attain such high temperatures, the compressed air used to burn the coal (or other fuel) in the combustion chamber, must be preheated to at least 1100oC. A lower preheat temperature would be adequate if the air were enriched in oxygen. An alternative is to use compressed oxygen alone for combustion of the fuel, little or no preheating is then required Figure 4 Schematic of an open cycle MHD Generator The additional cost of the oxygen might be balanced by the savings on the preheated. The hot, pressurized working fluid leaving the combustor flows through a convergent-divergent nozzle similar to a rocket nozzle. In passing through the nozzle, the random motion energy of the molecules in the hot gas is largely converted into directed, mass motion energy. Thus, the gas emerges from the nozzle and enters the MHD generator unit at a high velocity. The MHD generator is a divergent channel (or duct) made of a heat-resistant alloy (e.g.Inconel) with external water cooling. The hot gas expands through the rocket like generator surrounded by powerful magnet. During the motion of the gas the positive and negative ions move to the electrodes and constitute an electric current. The magnetic field direction, which is at right angles to the fluid flow, would be perpendicular to the plane of paper. A number of oppositely located electrode pairs are inserted in the channel to conduct the electric current generated to an external load. The electrodes pair may be connected in various ways (see below). An MHD generator, unlike a conventional generator, produced direct current; this can be converted into commonly used alternating current by means of an inverter. The arrangement of the electrode connection is determined by the need to reduce losses arising from the Hall Effect. By this effect, the magnetic field acts on the MHD- generated (Faraday) current and produces a voltage in the flow direction of the working fluid rather than at right angles to it. The resulting current in an external load is then called the Hall current Various electrode connection schemes have been proposed to utilize the Faraday current while minimizing the Hall current. A better, but more complicated, alternative is to connect each electrode pair across a separate load, as in Fig (4  ). Figure 5 MHD electrode connections to minimize Hall current Another possibility is to utilize the Hall current only; each electrode pair is short-circulated outside the generator, and the load is connected between the electrodes at the two ends of the MHD generator (Fig 5  ) Figure 6 Use of Hall current in MHD generator

As the working fluid travels along the MHD generator and its energy is converted into electricity, its temperature falls. When the gas temperature reaches about 19000 C, the extent of ionization of the p potassium is insufficient to maintain an adequate electrical conductivity. This places a lower limit on the useful operating temperature of the MHD system. The large residual heat available from the hot discharge working gas can then be utilized in several ways. For example, it conserves to preheat the combustion air by way of a heat exchanger similar to the regenerator in a gas turbine. At this stage, some 25 to 35 percent of the heat energy in the working fluid should have been converted into electrical energy. The still hot gas leaving the air preheated would be used in waste heat (heat exchanger) boiler to produce steam for operating a turbine generator. In this way, another 25 to 30 percent of the initial heat should be recovered as electrical energy in combined cycle system. The seed material is recovered for successive use in seed recovery apparatus. Prior to the discharge of the working gas (as flue gas) from the steam boiler to the atmosphere the fly ash from the coal fuel must be removed. However, instead of discharging the flyash, as is usually done, it may have to be treated for recovery of the seed material which is mixed with ash. Unless the sulfur in the coal has been removed (i.e. in a fluidized bed combustor), the original potassium carbonate seed will have been converted into potassium sulphate. This must be extracted from the flyash and reconverted by chemical reactions into potassium carbonate. The removal of residual sulfur by the potassium carbonates seed eliminates need for desulfurization of the flue gas, but nitrogen oxides are not removed. When oxygen alone is used for combustion of the coal (or other fossil fuel), the problem of nitrogen oxide formation does not arise. However, if nitrogen (from air) is resent, the nitrogen oxide contents of the combustion gases will be high because of the required high temperature of the working fluid. Consequently, a controlled combustion procedure is used to reduce the nitrogen oxide level in the discharge flue gas. The air supplied to the combustion chamber is not sufficient to permit complete fuel burning, combustion of the unburned fuel gases is then completed by introducing additional air at a later stage, beyond the MHD generator. The lower combustion temperature is accompanied by a decrease in the nitrogen oxide concentration. For efficient practical realization an MHD system must have the following features; 1.	Air super heating arrangement to heat the gas to around 25000C, (the inlet temperature of MHD is about 25000C), so that the electrical conductivity of the gas is increased. 2.	     The combustion chamber must have low heat losses. 3.	      Arrangement to add a low ionization potential seed material to the gas to increase its conductivity. 4.	   Water cooled but electrically insulating expanding duct with long life electrodes. 5.	   Seed recovery apparatus- necessary for both environmental and economic reasons. 3.2.  Closed-cycle systems Two general types of closed cycle MHD generators are being investigated. In one type, electrical conductivity is maintained in the working fluid by ionization of a seed material, as in open-cycle systems; and in the other, a liquid metal provides the conductivity. The carrier is usually a chemical inert gas, although a liquid carrier has been used with a liquid metal conductor. The working fluid is circulated in closed loop and is heated by the combustion gases using a heat exchanger. Hence, the heat sources and the working fluid are independent. The working fluid is helium or argon with cesium seeding 1.	Seeded inert gas system. In a closed cycle system the carrier gas (argon/helium) operates in a form of Brayton cycle. The gas is compressed and heat is supplied by the source at essentially constant pressure; the compressed gas ten expands in the MHD generator and its pressure and temperature fall. After leaving the generator, heat is removed from the gas by a cooler, this is the heat rejection stage of the cycle. Finally the gas is recompressed and returned for reheating. Figure 7 A closed cycle MHD system

A closed cycle MHD system is shown in Fig (6). The complete system has three distinct but interlocking loops. On the left is the external heating loop. Coal is gasified and the gas (having a high peak value of about 5.35 MJ/Kg and at a temperature of about 5250C) is burnt in a combustor to provide heat. In the primary heat exchanger, is burnt in a combustor to provide heat. In the primary heat exchanger, this heat is transferred to a carrier gas argon/helium (working fluid) of the MHD cycle. The combustion products after passing through the air preheated (to recover a part of the heat of combustion products) and purifier (to remove harmful emissions) are discharged to atmosphere. Because the combustion system is separate from the working fluid, so also are the ash and flue gases. Hence, the problem of extracting the seed material from flyash does not arise. The flue gases are used to preheat the incoming combustion arise and then rerated for the flyash and sulpher-dioxide, removal, if necessary, prior to discharge through a stack to the atmosphere.

The loop in the centre is the MHD loop. The hot argon gas is seeded with cesium and resulting working fluid is passed through the MHD generator at high speeds. The D.C. power out of MHD generator is converted to A.C. by the inverter and is then fed into the grid.

The loop shown on the right hand side in figure is the steam loop for further recovery of the heat of working fluid and converting this heat into electrical energy in the diffuser the working fluid is slowed down to a low subsonic speed. Then hot fluid enters a secondary heat exchanger, which serves as a waste heat boiler to generate steam. This steam is partly utilized to drive a turbine generator and for driving a turbine which runs the argon (or helium) compressor. The output of the generator is also fed to the main grid. The working fluid is returned back to primary heat exchanger after passing through compressor and inters cooler.

A closed cycle system can provide more useful power conversion at lower temperature (around 19000 K as compared to 25000 K for open cycle system). The somewhat lower operating temperatures of a closed cycle, MHD converter than of an open cycle system have an advantage in permitting a wider choice of materials. On the other hand, the lower temperature of the working fluid also means a lower thermal efficiency. Furthermore temperatures in the combustion chamber are still high, and special construction materials are required for the primary heat exchanger. Moreover the working fluid must be kept absolutely pure. The electrical stability of the flow in the generator poses problems because the gas is subjected to electrical fields approaching breakdown conditions.

The closed cycle MHD using rare gases as working fluid is developed and it is the most promising system among all. Generally, the heat source used is gas cooled nuclear reactor. 2.  Liquid Metal System. When a liquid metal provides the electrical conductivity, an inert gas (i.e. argon or helium) is a convenient carrier. The carrier gas is pressurized and heated by passage through a (primary) heat exchanger within the combustion chamber. The hot gas is then incorporated into the liquid metal, usually hot sodium, to form the working fluid. The latter then consists of gas bubbles uniformly dispersed in an approximately equal volume of liquid sodium Figure 8 Closed-cycle MHD Generator The working fluid is introduced into the MHD generator through a nozzle in the usual ways; the carrier gas then provide the required high directed velocity of the electrical conductor ( i.e. the liquid metal) After passing through the generator, the liquid metal is separated from the carrier gas. Part of the heat remaining in the gas is transferred to water in a (secondary) heat exchanger to produce steam for operating a turbine generator. Finally the carrier gas is cooled, compressed, and returned to the combustion chamber for reheating and mixing with the recovered liquid metal. The working fluid temperature is usually around 8000, as the boiling point of the sodium, even under moderate pressure, is below 9000

The lower operating temperature ten another MHD conversion systems may be advantageous from the material standpoint, but the maximum thermal efficiency is lower. A possible compromise might be to use liquid lithium, with a boiling point near 13000C, as the electrical conductor. Lithium is much more expensive than sodium, but losses in a loosed system be small. The closed cycle liquid metal system has the basic advantage of high electrical conductivity. However, liquids being practically incompressible, high Velocities cannot be produced by expansion as in the case of gas. In order to achieve reasonable velocities, either in low efficiency jet pumps or a two-phase system with vapour bubbles can be used. Even though liquid metal are excellent conductors, their vapours are poor electrical conductors. Thus there are several partial problems which have to be solved before liquid metal MHD systems can be commercially exploited. These systems are also appropriate for being coupled to nuclear reactors and the temperature range of interest to the liquid meal MHD (8000K- 13000K) is similar to liquid metal fast breeder reactors.

A liquid metal MHD cycle is illustrated in Fig (9), in which liquid potassium after being heated in breeder reactor is passed through a nozzle to increase its velocity. The vapour formed due to nozzle action are separated in the separator and condensed and then pumped back to the reactor as shown. Then the liquid metal with high velocity attained is passed through MHD generator to produce D.C. power. The liquid potassium coming out to MHD generator is passed through the conventional stem plant, where in the heat exchanger the heat of liquid potassium is utilized to generate steam to run steam turbine generator.

Figure 9 Closed cycle MHD generator using liquid metal as                                  Working fluid coupled with steam generator

4 	MHD Design Problems and Developments The experiments have been demonstrated for the scientific feasibility of MHD generation, but the efficiencies attained so far have been relatively low and the life of the equipment has been short. Some of the matters requiring resolution before MHD generation can become economically practical are outlined below.

The combustor, MHD-generator channel, electrodes, and air preheated are exposed to corrosive combustion gases at very high temperatures, materials must be developed to permit an adequate operating life for the components. The ash (or slag) residue from the burning coal is carried over with the combustion gases and tends to cause erosion of exposed surfaces. However, deposition of the slag on such surfaces may provide some protection. Another problem is separation of the seed material (as potassium sulfate) from the flyash and its reconversion into its original (carbonate) form.

The difficulties associated with slag and seed recovery can be eliminated by using a fuel gas derived from coal rather than coal itself, in the combustor (open cycle system). An ash free low heat value fuel gas, made from coal at a moderate cost and treated for sulfur removal would make a suitable fuel for MHD conversion combustion. Burning of gas in preheated air should provide adequate working fluid temperatures.

A more advanced concept is to use hydrogen gas made from coal and water. When this s burned in (compressed) oxygen, the product would be high temperature steam. After seeding and passage as working fluid through the MHD generator, the steam would be used to drive a turbine-generator, thus avoiding the need for a waste-heat boiler.

The power output of an MHD generator is theoretically proportional to the square of the magnetic field strength (Equation 12.6.17) hence a strong magnetic field is desirable. Conventional electro-magnets, in which the field is generated by direct current passing through water-cooled copper coils, have been used in MHD studies. Such magnets would not be partial for large scale MHD power generation because they would require very large current, will be necessary. Magnets of this type are being developed for use of MHD generators. 5	ADVANTAGES OF MHD POWER GENERSTION

MHD power generation offers several advantages over other conventional methods of power generation. Some of these are given below: 1.	Since high temperatures are involved, operation efficiency is high. 2.	No moving part, so more reliable 3.	Lesser thermal pollution. 4.	Conceptually such generators are simpler. 5.	As there is no limitation to the size of the duct, so high capacity generators are possible. 6.	The wall can be cooled below temperature of working gas. 7.	Direct conversion of heat into electrical energy results in elimination of the gas turbine (compared with a gas turbine power  plant) and both the boiler and turbine (compared with a conventional steam power plant) and thus is reduction of energy losses. 8.	Ability of reaching the full power level instantly. 9.	The more efficient heat utilization reduces the amount of heat discharged to environments and thus the cooling water requirements are reduced. 10.	The capital costs of the MHD plants are estimated to be competitive with those of coal fired steam power plants. 11.	The overall costs of the MHD power generation are also estimated to be lower (roughly 20%) than those of conventional power plants. This is because of higher efficiency of MHD power generation. 12.	The reduced fuel consumption that is obtained because of higher efficiency or better fuel utilization, offer additional economic and social benefits and also lead to conservation of energy sources. 13.	All kinds of heat sources such as coal, oil, gas, solar and nuclear can be used with MHD generators. 14.	MHD generators have low specific weight, rapid start, high power density and compact. In spite of the several inherent advantages the MHD system has not been accepted commercially because numerous technological advancements are needed prior to its commercialization. Most of these are related to material problems caused by high temperature and highly corrosive and abrasive environment. The MHD channel operates under extreme conditions of temperature. Development of MHD programmes has been undertaken by different countries during the last two decades. In India also considerable studies have been carried out in this field by a team of scientists under the National Council of Science and Technology. The department of Science and Technology of Govt. of India has sponsored research and development programmes on coal based MHD power generation. Bhabha Atomic Research Centre in collaboration with Bharat Heavy Electricals Ltd and Institute of High Temperature Russia is also executing Research and Development programmes in this field Russia has constructed pilot plant of 75 MW installed capacity, 25 MW is provided by the MHD Generator. The fuel used in natural gas. The plant is designated as “U-25”. A 5-15 MW thermal input pilot plant is being setup in India at Tiruchirapalli. This plant uses fluidized bed combustion. Major countries involved with MHD activities are Russia, USA, Japan, Australia, China, India, Italy, Israel, Poland etc. Besides the use of MHD system for commercial electrical power generation, it has got other special uses. A Major effort was made in USA to use MHD as the conversion system in a nuclear electrical system for space craft’s. MHD conversion has also been considered for ship propulsion, air born applications, hypersonic wind tunnel experiments and for many other defense applications. — Preceding unsigned comment added by Gaurav1021 (talk • contribs) 08:52, 27 June 2011 (UTC)

Magnetic Drug Targeting
Ferrofluids have nothing to do with MHD, so it's a bad example of applications for MHD. — Preceding unsigned comment added by 82.130.106.41 (talk) 15:19, 20 October 2011 (UTC)

Engineering -- controversial items
Regarding these two sentences in the "Engineering" section: Two widely-reported new applications for MHD drives are the hydrino reactor developed by Dr. Randell Mills of BlackLight Power in Cranbury, N.J., and the Energy Catalyzer, or E-Cat, developed by electrical engineer Andrea Rossi of Miami, Fla. Both of these inventors' devices can produce enormous amounts of heat that theoretically can then be converted to electricity by a MHD drive.

I'm actually hoping that such LENR devices will eventually be shown to be revolutionary energy devices, but the present sentences appear to state, without reservation, that these devices "can produce enormous amounts of heat." In fact, (as of this writing) such claims are quite controversial.

Also, the two sentences appear just before a sentence regarding coal-powered MHD abrasion problems -- seems out of place to me.

Dfgriggs (talk) 14:50, 26 March 2014 (UTC)

How can a plasma be a fluid?
Consider:

 * ... is the study of the dynamics of electrically conducting fluids. Examples of such fluids include plasmas, liquid metals, and salt water or electrolytes. ...

If the four states of matter are solid, fluid, gas and plasma, why are plasmas considered fluids? --Mortense (talk) 16:16, 9 July 2014 (UTC)
 * The four states of matter are solid, liquid... --Musaran (talk) 21:16, 23 July 2014 (UTC)
 * The four states of matter are solid, liquid, gas, and plasma. Fluid is a broader concept that encompasses anything that can flow. That usually includes liquid, but in aerodynamics gas is a fluid, in geophysics the solid parts of the earth can behave as fluids over sufficiently long period of time. Zyxwv99 (talk) 21:59, 23 July 2014 (UTC)

Define J
Isn't J just ρ v ? If so, this should be said when J is intrduced. 89.217.22.3 (talk) 16:13, 8 November 2014 (UTC)

MHD sensor

If is not directly related to Magnetohydrodynamics why is MHD sensor, which redirects to Magnetohydrodynamics, included on  ? Peter Horn User talk 03:04, 24 October 2016 (UTC)
 * MHD sensor is listed as an navigation instrument. Peter Horn User talk 03:20, 24 October 2016 (UTC)

Isambard Kingdom (talk) 03:24, 24 October 2016 (UTC)
 * Image added for good measure. Peter Horn User talk 11:37, 24 October 2016 (UTC)

External links modified
Hello fellow Wikipedians,

I have just modified 3 external links on Magnetohydrodynamics. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
 * Added archive https://web.archive.org/web/20070810223700/http://www.oulu.fi/~spaceweb/textbook/mhdwaves.html to http://www.oulu.fi/~spaceweb/textbook/mhdwaves.html
 * Added archive https://web.archive.org/web/20140820045250/http://read.pudn.com/downloads165/ebook/756655/Strapdown%20Inertial%20Navigation%20Technology/13587_04b.pdf to http://read.pudn.com/downloads165/ebook/756655/Strapdown%20Inertial%20Navigation%20Technology/13587_04b.pdf
 * Added archive https://web.archive.org/web/20080905113821/http://navier.stanford.edu/PIG/PIGdefault.html to http://navier.stanford.edu/PIG/PIGdefault.html

When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.

Cheers.— InternetArchiveBot  (Report bug) 22:23, 26 July 2017 (UTC)

External links modified
Hello fellow Wikipedians,

I have just modified one external link on Magnetohydrodynamics. Please take a moment to review my edit. If you have any questions, or need the bot to ignore the links, or the page altogether, please visit this simple FaQ for additional information. I made the following changes:
 * Added tag to http://epsppd.epfl.ch/Praha/98icpp/g096pr.pdf
 * Added archive https://web.archive.org/web/20110722013255/http://ftp.rta.nato.int/public//PubFullText/RTO/EN/RTO-EN-AVT-116///EN-AVT-116-15.pdf to http://ftp.rta.nato.int/public//PubFullText/RTO/EN/RTO-EN-AVT-116///EN-AVT-116-15.pdf

When you have finished reviewing my changes, you may follow the instructions on the template below to fix any issues with the URLs.

Cheers.— InternetArchiveBot  (Report bug) 18:18, 12 January 2018 (UTC)

Relevance of images in "Ideal and resistive MHD" section
Hello all. Going over the Magnetohydrodynamics section, I have noticed that the two provided images do not seem very relevant per MOS:IMAGERELEVANCE. One shows an MHD simulation of the solar wind and the other shows an MHD flow simulation. I fail to see how either are "signficant and relevant in the topic's context", so I will be removing them shortly. I bring this up here, as I might be missing something; however, if I am not seeing the significance and relevance as someone who is familiar with the topic, I do not think a reader would. CoronalMassAffection (talk) 14:15, 31 January 2023 (UTC)

MHD as "the study of ..."
Hello all. In the lead, MHD is presented as "the study of the magnetic properties and behaviour of electrically conducting fluids" (a statement that is supported in the given source). However, I was under the impression that MHD is just a model of fluid/plasma behavior (like Vlasov and two-fluid), not the study of magnetic properties and behavior of these fluids generally. My experience is mostly limited to MHD as it is used in astrophysics, so maybe it is used differently in other fields? CoronalMassAffection (talk) 16:26, 8 February 2023 (UTC)

 * Update: The statement in question was added unattributed [//en.wikipedia.org/w/index.php?title=Magnetohydrodynamics&diff=prev&oldid=522387 in 2002]. It has since changed in wording, but the meaning has not changed. Added later, the first supporting source is WP:CIRCULAR; the source, a book published in 2018, directly copies the lead paragraph. The second source, a 1967 thesis, is the only reference that supports this statement at the moment. CoronalMassAffection (talk) 17:09, 8 February 2023 (UTC)

 * I have found an RS, An Introduction to Magnetohydrodynamics by P. A. Davidson and published in the American Journal of Physics, that apparently introduces MHD as "the study of the interaction of magnetic fields and conducting fluids" according to a review from David J. Griffiths written in 2001. I unfortunately do not have access to this text. CoronalMassAffection (talk) 06:31, 1 August 2023 (UTC)
 * I now have access. From page 1: "Magnetohydrodynamics (MHD for short) is the study of the interaction between magnetic fields and moving, conducting fluids." Regardless, MHD is presented as a model or set of equations almost everywhere else in the literature, so I think we should continue to describe it as such here. CoronalMassAffection (talk) 09:17, 22 May 2024 (UTC)

Use of the term magnetosonic
I think that it is worth pointing out that some authors tend to use the term magnetosonic wave or magnetoacoustic wave to describe only the (fast) modes with wavevector perpendicular to the magnetic field, while others tend to use the term to describe all compressible MHD modes (i.e., both the fast and slow modes at all angles). Currently, some of the article follows the former convention, but I think we should follow the latter (like the Magnetosonic wave article). I will be MOS:BOLD and carry out this change. CoronalMassAffection (talk) 15:32, 31 May 2023 (UTC)

title: Talk:Magnetohydrodynamics


text: User talk:24.60.133.207

title: User talk:24.60.133.207


text:
Wikipedia:Articles for deletion/Anarchism (word)

 This page is an archive of the discussion about the proposed deletion of the article below. This page is no longer live. Further comments should be made on the article's talk page rather than here so that this page is preserved as an historic record. The result of the debate was delete. Sjakkalle (Check!)  11:26, 19 Jun 2005 (UTC)

Anarchism_%28word%29
This simply lists a lot of stuff, it should really be at the Anarchism (disambiguation) page. As such I see no reason for it to stick around. harrismw 06:21, 8 Jun 2005 (UTC)

 * Transwiki to wiktionary. Blackcats 09:58, 8 Jun 2005 (UTC)
 * Wiktionary has had anarchism since 2003-09-03. In any case, this isn't about the word at all.  The article is mis-titled.  Uncle G 13:22, 2005 Jun 8 (UTC)
 * This isn't disambiguation. It isn't disambiguating between different encyclopaedia articles entitled Anarchism.  We already have a anarchism (disambiguation) for that (although it doesn't seem to be actually disambiguating between multiple articles by the same title, either).  Nor is it about the word "anarchism".  This is a list of movements and organizations that in some fashion or other profess, by their titles, to be anarchist.  We already have a list of anarchist organizations for that.  If you want to have "These aren't anarchist organizations!"/"Oh yes they are!" arguments, find some way of settling them on that page, without POV forking. Merge if GFDL requires it, which given the histories and the contexts in which this is mentioned on talk pages seems unlikely. Delete as useless and mis-titled fork otherwise. Uncle G 13:22, 2005 Jun 8 (UTC)
 * Delete : did I say this is really getting silly? Saswann 13:54, 8 Jun 2005 (UTC)
 * I would say Delete... the edit-war between the capitalists and the socialists has unfortunately spawned an excess of articles with no logical reason for existence. *Dan* 14:00, Jun 8, 2005 (UTC)
 * Delete Another fluff page, product of this never-ending revert war.  Kev 20:18, 8 Jun 2005 (UTC)
 * Delete per Uncle G. carmeld1 04:37, 9 Jun 2005 (UTC)
 * Delete unnecessary fork. JamesBurns 07:11, 9 Jun 2005 (UTC)
 * Delete, though having a redirect to the actual disambiguation page might help in discouraging recreation. -- Jonel 19:06, 9 Jun 2005 (UTC)
 * Comment: This listing, and any problems with the article itself, are simply symptoms of the ongoing POV war in the anarchism wikispace. Wikipedia needs a conclusive means of resolving POV wars. — Phil Welch 00:45, 11 Jun 2005 (UTC)
 * This page is now preserved as an archive of the debate and, like some other VfD subpages, is no longer 'live'. Subsequent comments on the issue, the deletion, or the decision-making process should be placed on the relevant 'live' pages.  Please do not edit this page .


text:
Juan Luis Sanfuentes

Juan Luis Sanfuentes Andonaegui (27 December 1858 – 16 July 1930) was President of Chile between 1915 and 1920.

Sanfuentes was the son of writer and politician Salvador Sanfuentes Torres and Matilde Andonaegui. Orphaned at an early age and raised by his older brother, Enrique Salvador Sanfuentes, he trained as a lawyer at the University of Chile. He graduated with a Doctor of Law in 1879. He married Ana Echazarreta (ca. 1865–1927) in 1885, and the couple had five children.

Rising to the position of Minister of Finance under Federico Errázuriz Echaurren in 1901, Sanfuentes served as President of the Senate of Chile from 1906 through 1909.

The Chilean presidential election of 1915 developed into a bitter contest between Sanfuentes —a coalition candidate of the Liberal Democratic Party and the Conservative Party— and Javier Ángel Figueroa —supported by the Liberal Alliance parties. Sanfuentes beat Figueroa by a single vote, among allegations of fraud and electoral intervention. The National Congress was called to confirm the result.

Through World War I Chile remained neutral. While the conflict lasted, domestic industry had one of its biggest booms, with the national industry growing 53% in those four years. But the end of the war led to a crisis of the nitrate industry, which resulted in a wave of social unrest.

Sanfuentes' hard line against striking coal miners and trade unionists in the final year of his presidency was a key factor in the rise of his liberal reformer successor.

After office, Sanfuentes retired from public life, devoting himself to family life with his wife in his estate, Camarico, near Talca.

Foreign Honours
🇵🇹 Portugal: 🇪🇸 Spain:
 * PRT_Military_Order_of_the_Tower_and_of_the_Sword_-_Grand_Cross_BAR.png Grand Cross of the Order of the Tower and Sword (22 April 1921)
 * ESP Charles III Order GC.svg Grand Cross of the Order of Charles III (19 June 1922)

title: Juan Luis Sanfuentes


text:
Jungle rot

Jungle rot may refer to:

In medicine

 * Tropical ulcer, a chronic ulcerative skin lesion caused by polymicrobial infection
 * Trench foot, damage to feet from cumulative water immersion, particularly in the context of the US involvement in the Vietnam War

In media

 * Jungle Rot (band)

title: Jungle rot


text:
Strange and Beautiful (Aqualung album)

Strange and Beautiful is Aqualung's first US album release: a compilation of tracks from Aqualung's first two albums: Aqualung and Still Life. This compilation making up his first US release includes "Strange and Beautiful," "Brighter Than Sunshine," and "Falling Out of Love."

The track "Brighter Than Sunshine" reached #32 on the Billboard Adult Top 40 Chart in the U.S. Strange and Beautiful reached #108 on the Billboard Top 200 and also hit #1 on the Top Heatseekers Chart. As of December 2006, the album has sold over 250,000 copies in the US.

The song "Left Behind" (track 7) was used in a series of commercials for Chrysler. The song "Strange and Beautiful" is also featured on the soundtrack of the motion picture Wicker Park as well as the film A Lot Like Love.

Track listing

 * 1) "Strange & Beautiful (I'll Put a Spell on You)" – 3:51
 * 2) "Falling Out of Love" – 4:03
 * 3) "Good Times Gonna Come" – 3:53
 * 4) "Brighter Than Sunshine" – 4:01
 * 5) "Breaking My Heart" – 3:29
 * 6) "Tongue-Tied" – 3:52
 * 7) "Left Behind" – 3:47
 * 8) "You Turn Me Round" – 4:19
 * 9) "If I Fall" – 4:54
 * 10) "Easier to Lie" – 3:14
 * 11) "Extra Ordinary Thing" – 3:18
 * 12) "Another Little Hole" – 5:34

title: Strange and Beautiful (Aqualung album)


text:
User:Jdoty

Yo.

title: User:Jdoty


text:
File:Strange and Beautiful.jpg

Summary
Cover for the album Strange and Beautiful by Aqualung.

Fair use rationale for Strange and Beautiful
This image, Strange and Beautiful.jpg, is being linked here; though the picture is subject to copyright I (kollision) feel it is covered by the U.S. fair use laws because:
 * 1) the image is being used to illustrate the album in question.
 * 2) no free or public domain alternatives are available for this album.
 * 3) the image is of lower resolution than the original cover.
 * 4) it does not limit the copyright owner's rights to sell the CD album in any way.
 * 5) the image is being used for informational purposes only.

title: File:Strange and Beautiful.jpg


text:
Athabasca (Alberta provincial electoral district)

Athabasca was a provincial electoral district in Alberta, Canada, mandated to return a single member to the Legislative Assembly of Alberta from 1905 to 1986.

History
The Athabasca electoral district was one of the original 25 electoral districts contested in the 1905 Alberta general election upon Alberta joining Confederation in September 1905. Throughout the years the district's boundaries would continue to change; however, the district would remain in North-East Alberta throughout the 81 years of its existence.

The Athabasca electoral district would return a single member to the Legislative Assembly through first-past-the-post system of voting from 1905 until 1924, when the United Farmers government introduced the new The Alberta Election Act which would institute instant-runoff voting in rural electoral districts throughout the province. Instant-runoff voting would remain until the Social Credit government introduced amendments to The Election Act prior to the 1959 Alberta general election which returned every district in the province to a single member elected through first-past-the-post voting system. Instant-runoff voting would have a relatively minor effect on the Athabasca district, as elected members received a plurality of votes (above 50%) in all general elections besides 1926, 1940 and 1955.

The Athabasca district was re-distributed prior to the 1986 Alberta general election. The area the district covered was merged with Lac La Biche to form the riding of Athabasca-Lac La Biche.

1905
The Athabasca electoral district was created in 1905 as part of the original twenty-five electoral districts when Alberta was formed into a province from the Northwest Territories. The district consisted mostly of undeveloped wilderness covering the eastern half of northern Alberta. In 1905 the primary occupation was hunting and trapping and the local economy existed around the fur trade. The town of Athabasca, which was the only major settlement in the district, was experiencing a boom at that time as people flocked north to buy real estate.

The provincial Liberal party nominated William Fletcher Bredin as their candidate. He was a pioneer fur trader and was well known in the district. He made history by becoming the first person acclaimed to serve in the Legislative Assembly of Alberta. The provincial Conservative party being very weak in organization in northern Alberta was unable to find a candidate to oppose him. This was the only electoral district during this general election that sent a candidate to Edmonton by acclamation.

1948 electrification plebiscite
District results from the first province wide plebiscite on electricity regulation:

1957 liquor plebiscite
On October 30, 1957, a stand-alone plebiscite was held province wide in all 50 of the then current provincial electoral districts in Alberta. The government decided to consult Alberta voters to decide on liquor sales and mixed drinking after a divisive debate in the legislature. The plebiscite was intended to deal with the growing demand for reforming antiquated liquor control laws.

The plebiscite was conducted in two parts. Question A, asked in all districts, asked the voters if the sale of liquor should be expanded in Alberta, while Question B, asked in a handful of districts within the corporate limits of Calgary and Edmonton, asked if men and women should be allowed to drink together in establishments.

Province wide Question A of the plebiscite passed in 33 of the 50 districts while Question B passed in all five districts. Athbasca voted by a large majority in favor of the issue. The district recorded one of the lowest turnouts, well below the province wide 46% average.

Official district returns were released to the public on December 31, 1957. The Social Credit government in power at the time did not consider the results binding. However, the results of the vote led the government to repeal all existing liquor legislation and introduce an entirely new Liquor Act.

Municipal districts lying inside electoral districts that voted against the plebiscite were designated Local Option Zones by the Alberta Liquor Control Board and considered effective dry zones. Business owners who wanted a license had to petition for a binding municipal plebiscite in order to be granted a license.

By-elections and member party changes

 * September 27, 1918 — Appointment of Alexander Grant MacKay as the Minister of Municipal Affairs
 * June 3, 1920 — Death of Alexander Grant MacKay
 * November 4, 1935 — Resignation of Clarence Tade to provide a seat for Minister Charles Cathmer Ross
 * November 7, 1938 — Death of Charles Cathmer Ross
 * 1921 - 1926 — George Mills became an Independent Liberal (date not available).
 * 1926 - 1930 — John W. Frame crossed the floor from the Liberals to the United Farmers of Alberta (date not available).


text: User talk:203.153.238.226

title: User talk:203.153.238.226


text:
Emiliano Figueroa

Emiliano Figueroa Larraín (12 July 1866 – 16 May 1931) was President of Chile from December 23, 1925, until his resignation on May 10, 1927. He also served as acting president for a few months in 1910.

Biography
Figueroa was born on July 12, 1866, in Santiago, son of Francisco de Paula Figueroa Araoz and of Rosalía Larraín Echeverría. He studied in the San Ignacio School and then went on to study law at the State University. He graduated in 1889 and that same year was named secretary to the Intendant of Santiago.

Figueroa decided to embark on a political career and joined the Liberal Democratic Party, which supported a stronger executive. He was elected deputy for Victoria and Melipilla in 1900 and reelected in 1903. In 1907, once his term had ended, he was selected to replace Juan José Valenzuela, deputy for Rere and Puchacay, who had died in July that year. In 1909, Figueroa was once again elected to the Chamber of Deputies, this time representing Itata.

On October 25, 1907, President Pedro Montt named Figueroa Minister of Justice, a position which he kept until September 15, 1909. President Montt died on August 16, 1910, and was replaced by his Minister of Interior, Elías Fernández Albano, who became acting president. Fernández named Figueroa Minister of Interior but died on September 6 that very year. Figueroa then replaced Fernández as acting president and stayed in that position until December 23, when Ramón Barros Luco was inaugurated as president.

Barros named Figueroa to the post of ambassador to Spain in 1911, and in 1914 became ambassador to Argentina. Figueroa was considered a harmless politician and the three major political parties in Chile, Conservative, Liberal, and Radical, chose him as a consensus candidate for the 1925 Chilean presidential election. The purpose of having a single candidate was to avoid political campaigning in the volatile political situation the country was in. Nevertheless, leftist José Santos Salas ignored the three parties' agreement and declared his candidacy, backed by the Social Republican Worker's Union.

Figueroa easily defeated Salas and became president on 23 December 1925. Figueroa kept the ambitious General Carlos Ibáñez as Minister of War, and later named him Minister of the Interior. In 1927, Ibáñez ordered the arrest of Figueroa's brother Javier Ángel, President of the Supreme Court. Unable to withstand the political pressure, Figueroa resigned and Ibáñez became acting president. After winning the presidential election that year with 98% of the vote, Ibáñez became president and wielded dictatorial powers.

Ibáñez named Figueroa ambassador to Peru in 1928. Upon his return in 1929, Figueroa became president of the Central Bank of Chile. He died in a car accident on May 16, 1931.

title: Emiliano Figueroa


text: User talk:85.99.194.44

title: User talk:85.99.194.44


text:
Strange News from Another Star

Strange News from Another Star is a collection of eight short stories written by the German author Hermann Hesse between 1913 and 1918. It was first published as Märchen in German in 1919 and was translated to English by Denver Lindley in 1972. The first English publication was in 1972.

Stories
The stories, with the year in which they were written, are:
 * "Augustus" (1913)
 * "The Poet" (1913)
 * "Flute Dream" (1914)
 * "Strange News from Another Star" (1915)
 * "The Hard Passage" (1917)
 * "A Dream Sequence" (1916)
 * "Faldum" (1916)
 * "Iris" (1918)

Märchen (which means Fairy Tales) comprised seven of these stories. "Flute Dream" was added for the English publication in 1972 as per an arrangement Hesse had made for the final collected edition of his works.

These stories were also published in The Complete Fairy Tales of Hermann Hesse in 1995 with a new English translation by Jack Zipes. Two of the stories' English titles changed with this new translation:
 * "Strange News from Another Star" became "Strange News from Another Planet"
 * "The Hard Passage" became "The Difficult Path"

Background
These stories were written before and during the First World War and brought Hesse into conflict with supporters of the war, his country and its government. Unlike his earlier works, these stories do not lend themselves to rational interpretation. They are essentially fairy tales dealing with dream worlds, the subconscious and magic. In these stories, Hesse challenged conventional intellectual life and the orthodoxy of the world.

In popular culture

 * Blur's 1997 self-titled fifth album contains a song of the same name.

title: Strange News from Another Star