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Junkers Jumo 205

The Jumo 205 aircraft engine was the most famous of a series of aircraft diesel engines produced by Junkers. The Jumo 204 first entered service in 1932. Later engines of this type comprised the experimental Jumo 206 and Jumo 208, with the Jumo 207 produced in some quantity for the Junkers Ju 86P and -R high-altitude reconnaissance aircraft, and the 46-meter wingspan, six-engined Blohm & Voss BV 222 Wiking flying boat. All three of these variants differed in stroke and bore and supercharging arrangements. In all, more than 900 of these engines were produced, in the 1930s and through most of World War II.

Design and development

These engines all used a two-stroke cycle with 12 pistons sharing six cylinders, piston crown to piston crown in an opposed configuration. This unusual configuration required two crankshafts, one at the bottom of the cylinder block and the other at the top, geared together. The pistons moved towards each other during the operating cycle. The intake ports were located at one end of the cylinder, whereas the exhaust ports were at the other end. This made one piston effectively control the intake, and the other control the exhaust. Two cam-operated injection pumps per cylinder were used, each feeding two nozzles, for four nozzles per cylinder in all.

As is typical of two-stroke designs, the Jumos used no valves, but rather fixed intake and exhaust port apertures cut into the cylinder liners during their manufacture, which were uncovered when the pistons reached a certain point in their strokes. Normally, such designs have poor volumetric efficiency because both ports open and close at the same time and are generally located across from each other in the cylinder. This leads to poor scavenging of the burnt charge, which is why valveless two-strokes generally produce smoke and are inefficient.

The Jumo largely addressed this problem through a clever arrangement of the ports. The intake port was positioned under the "lower" piston, while the exhaust port was under the "upper" piston. The lower crankshaft operated 11° behind the upper, causing the exhaust ports to open and close first, which allowed for proper scavenging. This design enabled the two-stroke Jumos to run nearly as cleanly and efficiently as four-stroke engines with valves, but with significantly less complexity.

Some downside exists to this system, as well. For one, since matching pistons were not closing at quite the same time, but one ran "ahead" of the other, the engine could not run as smoothly as a true opposed-style engine. In addition, the power from the two opposing crankshafts had to be geared together, adding weight and complexity, a problem the design shared with H-block engines.

In the Jumo, these problems were avoided to some degree by taking power primarily from the "upper" shaft, somewhat offset upwards on the engine's front end. All of the accessories, such as fuel pumps, injectors and the scavenging compressor, were run from the lower shaft, meaning over half of its power was already used up. What was left over was then geared to the upper shaft, which ran the engine's propeller.

In theory, the flat layout of the engine could have allowed it to be installed inside the thick wings of larger aircraft, such as airliners and bombers. Details of the oil scavenging system suggest this was not possible and the engine had to be run "vertically", as it was on all designs using it.

Because the temperature of the exhaust gases of the Jumo diesel engines was substantially lower than that of comparable carburettor engines, it was easier to add a turbocharger for higher altitudes. This was explored in the Jumo 207 which used the energy of the exhaust gases to increase the power at high altitudes. The turbocharger was combined with a mechanically driven blower, so that the turbocharger creates the first stage of compression, and the mechanical blower the second stage. At low load and startup, the turbocharger does not contribute to supercharging the engine, but the mechanical blower provides enough air for the engine to operate. At high load, however, the turbocharger receives sufficient quantities of exhaust gas, which means that it alone can provide enough supercharging without the need of the inefficient mechanical blower. The addition of the turbocharger to the mechanical blower made the engine more powerful without significantly increasing its specific fuel consumption.

Variants

 * Jumo 205:
 * Jumo 206: An experimental version. Development halted in favour of the Jumo 208.
 * Jumo 207A: High-altitude version with two inline centrifugal superchargers and a precooler.
 * Jumo 207 B-3 had an improved turbocharger and featured GM-1 nitrous oxide injection.
 * Jumo 207 C: optimised for medium altitude. Produced in small series for the Blohm & Voss BV 222.
 * Jumo 207 D: optimised for medium altitude. Cylinder diameter increased from 105 mm to 110 mm. Maximum power at ground level was 1,200 hp (880 kW). Prototypes only.
 * Jumo 207 E: similar to the 207 C but greater performance at high altitude. Project only.
 * Jumo 207 F: optimised for higher altitude. Two-stage turbocharger. Development stopped in 1942.
 * Jumo 208: with greater displacement, resulting in a maximum power of 1,500 hp (1,100 kW) at medium altitude. Bench tested but not produced.
 * Jumo 218: A 12-cylinder version, the Jumo 218, was designed but never built.
 * Jumo 223: A single 24-cylinder four-crankshaft Jumo 223 was built and tested.
 * Jumo 224: Larger than the Jumo 223 by combining 4 Jumo 207 C engines.
 * CLM Lille 6As: A license-built version from CLM Lille, delivering 650 hp (CLM was the predecessor to the Indenor engine maker, a sister company to Peugeot)
 * CLM Lille 6BrS: A developed version of the 6As used to power the Bernard 86

Applications
The Jumo 205 powered early versions of the Junkers Ju 86 bomber, but was found too unresponsive for combat and liable to failure at maximum power, common for combat aircraft. Later versions of the design also used the engine for extreme high-altitude use, as with the Ju 86P and -R versions for high-altitude reconnaissance over the British Isles. In January 1940, the Luftwaffe tested the prototype Ju 86P with Jumo 207A-1 turbocharged diesel engines. It was far more successful as a power unit for airships, for which its characteristics were ideal, and for noncombat applications such as the Blohm & Voss Ha 139 airliner. Its more fuel-efficient operation lent itself for use on Germany's few maritime patrol flying-boat designs during World War II, such as the BV 138 and BV 222.

Applications list

 * Blohm & Voss BV 138
 * Blohm & Voss Ha 139
 * Blohm & Voss BV 222
 * Dornier Do 18
 * Dornier Do 24 (V1 and V2 prototypes)
 * Dornier Do 26
 * Junkers Ju 86

Other notable opposed-piston engines

 * Commer TS3 the "Commer Knocker" commercial vehicle engine
 * Leyland L60 tank engine, used in the Chieftain tank, was similar in layout to the Junkers Jumo 205 and Napier Culverin.
 * Rolls-Royce K60 engine was used in the FV430 series of armoured fighting vehicles and Swedish tank Strv 103.
 * Napier Deltic
 * Soviet engine 5TDF was used in T-64 tank.
 * Soviet engine 6TD was used in T-80UD, T-84, and Al-Khalid tanks.
 * Fairbanks Morse 38 8 1/8

title: Junkers Jumo 205


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Harald Bohr

Harald August Bohr (22 April 1887 – 22 January 1951) was a Danish mathematician and footballer. After receiving his doctorate in 1910, Bohr became an eminent mathematician, founding the field of almost periodic functions. His brother was the Nobel Prize-winning physicist Niels Bohr. He was on the Denmark national team for the 1908 Summer Olympics, where he won a silver medal.

Biography
Bohr was born in 1887 to Christian Bohr, a professor of physiology, from a Lutheran background, and Ellen Adler Bohr, a woman from a wealthy Jewish family of local renown. Harald had a close relationship with his elder brother, which The Times likened to that between Captain Cuttle and Captain Bunsby in Charles Dickens' Dombey and Son.

Mathematical career
Like his father and brother before him, in 1904 Bohr enrolled at the University of Copenhagen, where he studied mathematics, obtaining his master's degree in 1909 and his doctorate a year later. Among his tutors were Hieronymus Georg Zeuthen and Thorvald N. Thiele. Bohr worked in mathematical analysis; much of his early work was devoted to Dirichlet series including his doctorate, which was entitled Bidrag til de Dirichletske Rækkers Theori (Contributions to the Theory of Dirichlet Series). A collaboration with Göttingen-based Edmund Landau resulted in the Bohr–Landau theorem, regarding the distribution of zeroes in zeta functions.

Bohr worked in mathematical analysis, founding the field of almost periodic functions, and worked with the Cambridge mathematician G. H. Hardy.

In 1915, he became a professor at Polyteknisk Læreanstalt (today Technical University of Denmark), working there until 1930, when he took a professorship at the University of Copenhagen. He remained in this post for 21 years until his death in 1951. Børge Jessen was one of his students there.

He was a visiting professor at Stanford University during the academic year 1930–1931. He was a visiting scholar at the Institute for Advanced Study in the summer of 1948.

Bohr was elected to the American Philosophical Society in 1945.

In the 1930s Bohr was a leading critic of the anti-Semitic policies taking root in the German mathematical establishment, publishing an article criticising Ludwig Bieberbach's ideas in Berlingske Aften in 1934.

Football
Bohr was also an excellent football player. He had a long playing career with Akademisk Boldklub, making his debut as a 16-year-old in 1903. During the 1905 season he played alongside his brother Niels, who was a goalkeeper. Harald was selected to play for the Denmark national team in the 1908 Summer Olympics, where football was an official event for the first time. Though a Danish side had played at the 1906 Intercalated Games, the opening match of the 1908 Olympic tournament was Denmark's first official international football match. Bohr scored two goals as Denmark beat the French "B" team 9–0. In the next match, the semi-final, Bohr played in a 17–1 win against France, which remains an Olympic record. Denmark faced hosts Great Britain in the final, but lost 2–0, and Bohr won a silver medal. After the Olympics he made one further appearance for the national team, in a 2–1 victory against an England amateur team in 1910. His popularity as a footballer was such that when he defended his doctoral thesis the audience was reported as having more football fans than mathematicians.

Teacher
Bohr was known as an extremely capable academic teacher and the annual award for outstanding teaching at the University of Copenhagen is called the Harald, in honour of Harald Bohr. With Johannes Mollerup, Bohr wrote an influential four-volume textbook Lærebog i Matematisk Analyse (Textbook in mathematical analysis).

Kaj Munk
Following the murder of Kaj Munk on 4 January 1944 the Danish resistance newspaper De frie Danske brought condemning reactions from influential Scandinavians, including Bohr.

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

title: Harald Bohr


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Talk:Snufkin

Reception needs more
"The character has a mostly positive reception." is true and don't get me wrong I love my man Snufkin, but this section could be a bit beefed up. — Preceding unsigned comment added by Alicepow8 (talk • contribs) 20:11, 17 June 2022 (UTC)

Untitled
Apologies for accidentially adding. The text sounded like nonsense to me before i noticed the link to the Moomins and the japanese language version. Sorry. -- Chris 73 | Talk 10:31, 6 May 2004 (UTC)

 * However, is this character really worth an entry on its own, or can this be incorporated into the Moomin entry and redirected there? --Robert Merkel 13:21, 6 May 2004 (UTC)
 * Very much worth one, and a longer one. Arguably the most important character.  69.49.44.11 06:30, 31 May 2007 (UTC)

 * That's a bit like asking whether Hamlet is worth an entry on his own. (He is, but Snufkin's much nicer.) Cooke (talk) 15:06, 12 September 2008 (UTC)

This article is missing snapshots of Snufkin. Anyone care to add a few? White Mage Cid 00:49, 9 December 2007 (UTC) —Preceding unsigned comment added by 81.167.234.84 (talk)
 * I have an SVG file I just drew that I may add as soon as I can work out the copyright on it…I drew it, but is the character copyright? Goyston talk, contribs, play 03:53, 25 October 2008 (UTC)
 * It's been uploaded. Goyston talk, contribs, play 19:00, 25 October 2008 (UTC)
 * With the best will in the world, and all due respect and so forth, this illustration should be removed. It's s a bit like someone else's idea of Van Gogh's Sunflowers, or Michaelangelo's David. Cooke (talk) 23:22, 26 December 2008 (UTC)
 * I see where you're coming from. My rationale for placing it was that all images created by the original author are copyright, and will be for some time. However, a visual representation of the character in question adds significant value to the article. It wouldn't be the same if no fair-use image was available of Angelina Jolie, so someone sketched one and uploaded it, but as a cartoon character, it's different. I may be totally off-base here, though, and if you feel like it should be removed, please remove it. Be bold! Goyston talk, contribs, play 07:07, 1 February 2009 (UTC)
 * Hi Goyston, I'm going to remove it, with great reluctance, because it was clearly placed there with the best of intentions; but I'm glad that you fully understand why.
 * I now have a moral obligation to clear copyright for an original image of snufkin for use on WP. Cooke (talk) 20:30, 6 April 2010 (UTC)
 * Sorry, but I have removed another pic. I recognize that it would be nice to have a picture but the wrong one is worse than no picture at all. Snufkin is a fictional character in a series of novels, and we don't need a picture of him.  Any pics other than those drawn by Tove Jansson are misleading and counterproductive. Cooke (talk) 13:18, 5 April 2011 (UTC)

Notability
This article has had added to it. Looking at the sources, I find it difficult to understand what's lacking. Please explain? Notability seems well established. /Julle (talk) 10:30, 23 June 2021 (UTC)
 * I've removed the tag for now. Please elaborate on what's missing if putting it back. /Julle (talk) 10:36, 24 June 2021 (UTC)

title: Talk:Snufkin


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Cash for comment affair

The cash for comment affair was an Australian scandal that broke in 1999 concerning paid advertising in radio that was presented to the audience in such a way as to sound like editorial commentary. John Laws, a shock jock radio presenter for Sydney talk back, was accused of misusing his authority as an announcer. While the initial publicity had died down by the end of the year, it sparked major changes in the way the radio industry is conducted in Australia. This resulted in a second scandal in 2004, leading to the resignation of Australian Broadcasting Authority head David Flint, after he had been found to have been less than impartial in his role in original "cash for comment" investigations.

Some have pointed to the Broadcasting Services Act (1992), which has treated the media more as a business than a cultural institution, for a decline in the relevance of ethical standards in the Australian media industry.

Reporting
In 1999, reporters Richard Ackland, Deborah Richards and Anne Connolly from ABC's Media Watch programme revealed that 2UE talk back hosts John Laws and Alan Jones had been paid to give favourable comment to companies including Qantas, Optus, Foxtel, Mirvac and major Australian banks, without disclosing this arrangement to listeners. Prior to giving favourable commentary to a group of banks, Laws had repeatedly criticised them for imposing unjustified fees on customers while cutting back on services.

Though they both initially vehemently denied any wrongdoing, Laws and Jones defended the practice by claiming that they were not employed as journalists but as "entertainers", and thus had no duty of disclosure or of journalistic integrity.

Inquiry
The Australian Broadcasting Authority (ABA) estimated the value of these arrangements at AUD$18 million, and found that Laws, Jones, and 2UE had committed 90 breaches of the industry code and five breaches of 2UE's license conditions. The inquiry heard that Laws received cash and VIP hospitality at Sydney's Star City Casino for not discussing negative aspects of gambling.

The ABA made it clear that Laws was not a journalist, but a radio personality, and so journalistic ethical standards didn't apply to him. The inquiry focused on the extent to which deliberate commercial endorsement had led to distortions in which the public was misled about important matters. Regulations were subsequently tightened to prevent such behaviour; however, the ABA was accused of weakness and inconsistency in enforcing these regulations. Included in the changes were new sponsor disclosure requirements. Laws used a cow bell to announce sponsor deals following more stringent disclosure requirements.

In 2004, Laws and Jones were again accused of cash for comment in relation to deals both had made with Telstra. Laws was found to have breached the rules but Jones was cleared; the revelation of flattering letters written by ABA head David Flint to Jones, at the same time that Jones was under investigation, led to accusations of impropriety that ultimately forced Flint's resignation.

Fines
2UE was fined $360,000 for Laws's improper conduct. Initially the radio station was to pay the Australian Communications and Media Authority (ACMA), the succeeding media regulatory agency to the ABA, AUD$10,000 for each of the 13 breaches involving a sponsor disclosure requirement. The Communications Law Centre intervened, arguing that a harsher penalty was appropriate. This led to the Federal Court imposing a larger fine.

title: Cash for comment affair


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Diana (camera)

The Diana camera is a plastic-bodied toy camera that uses 120 roll film and 35 mm film. The camera has a simple plastic meniscus lens. Originally marketed as an inexpensive novelty gift item, the Diana has been used to specifically take soft focus, impressionistic photographs somewhat reminiscent of the Pictorialist Period of artistic photography, branded in contemporary times as Lomography.

The Diana frequently suffers from light leaks, film advance issues, and other problems. However, its low-quality plastic lens has been celebrated for its artistic effects in photographs, normally resulting in a slightly blurred composition that can provide a 'dreamlike' quality to the print.

History
The Diana first appeared during the early 1960s as an inexpensive box camera sold by the Great Wall Plastic Factory of Kowloon, Hong Kong. Most were exported to the United States and the United Kingdom. In the United States, the Diana was imported by the Power Sales Company of Willow Grove, Pennsylvania. During the 1960s, Power Sales Company wholesaled the Diana by the case – 144 cameras – at about 50 cents U.S. per unit to a variety of retailers and promotional merchandisers.

Most Diana cameras were given away or sold for nominal sums as novelties or prizes at fairs, carnivals, product promotions, raffles, or other events. For a time, the camera was also regularly advertised for sale in various periodicals through mail order vendors. However, with the development of inexpensive, higher quality consumer cameras such as the Kodak Instamatic, together with the declining popularity of rollfilm, demand for the Diana – even as a novelty gift – gradually disappeared. Production of the Diana, its clones, close copies, and variants is believed to have stopped in the 1970s, though similar 35 mm box cameras were produced for many years thereafter by various companies in Hong Kong, Taiwan and China for use as promotional items.

It is currently marketed as the “Diana F+” in the original 120 format as well as "Diana Mini" in 35 mm format and the "Diana Baby 110" by Lomography. The current iteration of the medium-format Diana F+ is actually a system camera with interchangeable lenses, flashes, and film backs. Lomography also makes Diana lens adapters for several major DSLR systems, including Canon EOS, Nikon F-mount, and Micro Four Thirds.

A digital version of the camera was produced in 2014 by Greg Dash of Cyclops Cameras. The project was funded through crowdfunding platform Indiegogo, allowing Dash to produce a limited run of 1000 digital Diana cameras (a camera he called the 'Rhianna').

Characteristics and variants
The Diana is a very simply constructed box camera with a mechanical film advance, spring-loaded shutter, and a primitive plastic viewfinder. It is constructed primarily of low-quality phenolic plastics of the type commonly found in toys imported from Asia during the 1960s. Because of wide variances in production quality, combined with a poorly designed camera body latching mechanism, Diana cameras are predisposed to light leaks onto the exposed film. If not desired, such leaks can be temporarily remedied by sealing the seams with light-proof tape after loading the film. The design of the Diana incorporates a crude lens that produces an image circle which only marginally covers the diagonal of a film frame. This marginal coverage field produces images with often pronounced vignetting. The poor quality of the plastic meniscus lens results in generally low contrast and resolution, odd color rendition, chromatic aberration, and blurred images. Additionally, the film spool may become loose or out of place when winding the film on to the next frame. Finally, the crude advance and shutter mechanism can result in images that are not properly centered or exposed.

Although these attributes are generally thought undesirable in a camera, various photographers and art photography schools have intentionally utilized these characteristics to produce photographs with interesting or artistic effects. The San Francisco Art Institute seems to have been the first school to employ the Diana in its photography program in 1967-68 as a way of stimulating creative vision without undue reliance upon camera features and technology. Later other schools picked up the idea, including Ohio University in Athens, Ohio. The use of the Diana in this role achieved a new level of fame when the camera was utilized by American photographer (and former Ohio University photography student) Nancy Rexroth in an influential 1976 photographic exhibit and book entitled IOWA.

In addition to the 'Diana' labeled cameras, there are over fifty similar variants of the basic design, some of which may have been produced by other factories and/or manufacturers. The camera was sold under a variety of model names, often accomplished by merely affixing a different stick-on label to the same product. In other cases, slight modifications to the basic design were incorporated. Some Diana clones use a slightly different molding and plastic composition, while other models have a 'bulb' setting for time exposures. Other variants incorporate a 6×6 cm negative size (like the Diana Deluxe), while others have provision for different controls or even separate flash illumination. The 3 aperture version of the classic Diana/Diana clone has apertures of, , and , and it takes 32 mm clip-on filters. The Diana Deluxe variant offers, , and , and takes a 46–49 mm step-up ring, unusual for such a low-end camera.

A twist on the classic 1960s first version Diana, the latest Diana F+ was produced in 2007. The modern Diana F+ offers four apertures, including a pinhole. Shutter speed is often variable due to manufacturing vagaries, and can vary from 1/200th to 1/30th of a second. As there is no shutter lock, and the shutter mechanism is always held in tension by a spring, multiple exposures with the Diana can be achieved by multiple operations of the shutter release without advancing the film. The Diana F+ can be used with the Diana Instant Back+, the Diana 35mm Back+ as well as the splitzer so as to produce a series of dreamy, radiant and lo-fi photos.

title: Diana (camera)


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Damping factor

In an audio system, the damping factor is defined as the ratio of the rated impedance of the loudspeaker (usually assumed to be $8 Ω$) to the source impedance of the power amplifier. It was originally proposed in 1941. Only the magnitude of the loudspeaker impedance is used, and the power amplifier output impedance is assumed to be totally resistive.

In typical solid state and tube amplifiers, the damping factor varies as a function of frequency. In solid state amplifiers, the damping factor usually has a maximum value at low frequencies, and it reduces progressively at higher frequencies. The figure to the right shows the damping factor of two amplifiers. One is a solid state amplifier (Luxman L-509u) and the other is a tube amplifier (Rogue Atlas). These results are fairly typical of these two types of amplifiers, and they serve to illustrate the fact that tube amplifiers usually have much lower damping factors than modern solid state amplifiers, which is an undesirable characteristic.

Calculation
The source impedance (that is seen by the loudspeaker) includes the connecting cable impedance. The load impedance $$Z_\mathrm{L}$$ and the source impedance $$Z_\mathrm{S}$$ are shown in the circuit diagram.

The definition of damping factor $$DF$$ normally used to characterize audio amplifiers is: $$ DF = \frac{Z_\mathrm{L}}{Z_\mathrm{S}} $$

However, in this form $$DF$$ is not in fact proportional to the electrical circuit damping. The load is the source of energy being damped, and if $$Z_\mathrm{S}$$ = 0, the damping resistance in series with the energy source cannot fall below $$Z_\mathrm{L}$$ itself (unless $$Z_\mathrm{S}$$ is made negative, which is usually impractical). This fact was admitted and an improved definition was proposed: $$ DF = \frac{Z_\mathrm{L}+Z_\mathrm{S}}{Z_\mathrm{L}} $$ But the former definition has nevertheless become standard.

Explanation
Pierce undertook an analysis of the effects of amplifier damping factor on the decay time and frequency-dependent response variations of a closed-box, acoustic suspension loudspeaker system. The results indicated that any damping factor over 10 is going to result in inaudible differences between that and a damping factor equal to infinity. However, it was also determined that the frequency-dependent variation in the response of the loudspeaker due to the output resistance of the amplifier is much more significant than the effects on system damping. It is also important to not confuse these effects with damping effects, as they are caused by two quite different mechanisms. The calculations suggested that a damping factor in excess of 50 will not lead to audible improvements, all other things being equal.

For audio power amplifiers employing some global negative feedback, this source impedance $$Z_\mathrm{S}$$ is generally smaller than $0.1 Ω$, which from the point of view of the driver voice coil is a near short circuit.

The loudspeaker's nominal load impedance (input impedance) of $$Z_\mathrm{L}$$ is usually around $4 Ω$, although other impedance speakers are available, sometimes dropping as low as $1 Ω$ or $2 Ω$. However, the impedance rating of a loudspeaker is simply a number that indicates the nominal minimum impedance of that loudspeaker over a representative portion of its operating frequency range. It needs to be kept in mind that most loudspeakers have an impedance that varies considerably with frequency. For a dynamic loudspeaker driver, a peak in the impedance is present at the free-air resonance frequency of the driver, which can be significantly greater in magnitude than the nominal rated impedance. In addition, the electrical characteristics of every voice coil will change with temperature (high power levels increase voice coil temperature, and thus resistance), the inductance of voice-coil windings leads to a rising impedance at high frequencies, and passive crossover networks (composed of relatively large inductors, capacitors, and resistors) introduce further impedance variations in multi-way loudspeaker systems. Referring to the equation for $$DF$$ that was given above, this frequency-dependent variation in loudspeaker load impedance results in the value of the damping factor of the amplifier varying with frequency when it is connected to a loudspeaker impedance load.

In loudspeaker systems, the value of the damping factor between a particular loudspeaker and a particular amplifier describes the ability of the amplifier to control undesirable movement of the speaker cone near the resonant frequency of the speaker system. It is usually used in the context of low-frequency driver behavior, and especially so in the case of electrodynamic drivers, which use a magnetic motor to generate the forces which move the diaphragm. A high damping factor in an amplifier is sometimes considered to result in the amplifier having greater control over the movement of the speaker cone, particularly in the bass region near the resonant frequency of the driver's mechanical resonance.

Speaker diaphragms have mass, and their compliant suspension components have stiffness. Together, these form a resonant system, and the mechanical cone resonance may be excited by electrical signals (for example, pulses) at audio frequencies. But a driver with a voice coil is also a current generator, since it has a coil attached to the cone and suspension, and that coil is immersed in a magnetic field. For every motion the coil makes, it will generate a current that will be seen by any electrically attached equipment, such as an amplifier. In fact, the output circuitry of the amplifier will be the main electrical load on the "voice coil current generator". If that load has low resistance, the current will be larger, and the voice coil will be more strongly forced to decelerate. A high damping factor (which requires low output impedance at the amplifier output) very rapidly damps unwanted cone movements induced by the mechanical resonance of the speaker, acting as the equivalent of a "brake" on the voice coil motion (just as a short circuit across the terminals of a rotary electrical generator will make it very hard to turn). It is generally (though not universally) thought that tighter control of voice coil motion is desirable, as it is believed to contribute to better-quality sound.

The damping circuit
The voltage generated by the moving voice coil forces current through three resistances:
 * The resistance of the voice coil itself
 * The resistance of the interconnecting cable
 * The output resistance of the amplifier

Effect of voice coil resistance
This is the key factor in limiting the amount of damping that can be achieved electrically, because its value is larger (say between 4 and 8 Ω typically) than any other resistance in the output circuitry of an amplifier that does not use an output transformer (nearly every solid-state amplifier on the mass market).

A loudspeaker's flyback current is not only dissipated through the amplifier output circuit, but also through the internal resistance of the loudspeaker itself. Therefore, the choice of different loudspeakers will lead to different damping factors when coupled with the same amplifier.

Effect of cable resistance
The damping factor is affected to some extent by the resistance of the speaker cables. The higher the resistance of the speaker cables, the lower the damping factor.

Amplifier output impedance
Modern solid state amplifiers, which use relatively high levels of negative feedback to control distortion, have very low output impedances—one of the many consequences of using feedback—and small changes in an already low value change overall damping factor by only a small, and therefore negligible, amount.

Thus, high damping factor values do not, by themselves, say very much about the quality of a system; most modern amplifiers have them, but vary in quality nonetheless.

Vacuum-tube amplifiers typically have much lower feedback ratios, and in any case almost always have output transformers that limit how low the output impedance can be. Their lower damping factors are one of the reasons many audiophiles prefer tube amplifiers. Taken even further, some tube amplifiers are designed to have no negative feedback at all.

In practice
Typical modern solid-state amplifiers with negative feedback tend to have high damping factors, usually above 50 and sometimes even greater than 150. High damping factors tend to reduce the extent to which a loudspeaker "rings" (undergoes unwanted short-term oscillation after an impulse of power is applied), but the extent to which damping factors higher than about 20 help in this respect is easily overstated; there will be significant effective internal resistance, as well as some resistance and reactance in crossover networks and speaker cables. Older amplifiers, plus modern triode and even solid-state amplifiers with low negative feedback, will tend to have damping factors closer to unity, or even less than 1.

Although extremely high values of damping factor in an amplifier will not necessarily make the loudspeaker–amplifier combination sound better, a high damping factor can serve to reduce the intensity of added frequency response variations that are undesirable. The figure on the right shows the effect of damping factor on the frequency response of an amplifier when that amplifier is connected to a simulated loudspeaker impedance load. This load is moderately demanding but not untypical of high-fidelity loudspeakers that are on the market, and it is based on the circuit proposed by Atkinson. The audio magazines Stereophile and Australian Hi-Fi have recognised the importance of amplifier damping factor, and have made the use of the simulated loudspeaker load a routine part of their amplifier measurements. At around $4 kHz$, the real-life difference between an amplifier with a moderate (100) damping factor and one with a low (20) damping factor is about 0.37 dB. However, the amplifier with the low damping factor is acting more like a subtle graphic equaliser than is the amplifier with the moderate damping factor, where the peaks and dips in the amplifier's frequency response correspond closely to the peaks and dips in the loudspeaker impedance response.

It is clear from the various amplifier frequency response curves that low damping factor values result in significant changes in the frequency response of the amplifier in a number of frequency bands. This will result in broad levels of sound coloration that are highly likely to be audible. In addition, the frequency response changes will depend on the frequency-dependent impedance of whichever loudspeaker happens to be connected to the amplifier. Hence, in high-fidelity sound reproduction systems, amplifiers with moderate to high damping factors are the preferred option if accurate sound reproduction is desired when those amplifiers are connected to typical multi-way loudspeaker impedance loads.

Some amplifier designers, such as Nelson Pass, claim that loudspeakers can sound with lower electrical damping, although this may be attributed to listener preference rather than technical merit. A lower damping factor helps to enhance the bass response of the loudspeaker by several decibels (where the impedance of the speaker would be at its maximum), which is useful if only a single speaker is used for the entire audio range. Therefore, some amplifiers, in particular vintage amplifiers from the 1950s, 1960s and 1970s, feature controls for varying the damping factor. While such bass "enhancement" may be pleasing to some listeners, it nonetheless represents a distortion of the input signal.

One example of a vintage amplifier with a damping control is the Accuphase E-202, which has a three-position switch described by the following excerpt from its owner's manual: "Speaker Damping Control enhances characteristic tonal qualities of speakers. The damping factor of solid state amplifiers is generally very large and ideal for damping the speakers. However, some speakers require an amplifier with a low damping factor to reproduce rich, full-bodied sound. The E-202 has a Speaker Damping Control which permits choice of three damping factors and induces maximum potential performance from any speaker. Damping factor with an $8 Ω$ load becomes more than 50 when this control is set to NORMAL. Likewise, it is 5 at MEDIUM position, and 1 at SOFT position. It enables choosing the speaker sound that one prefers."

Damping is also a concern in guitar amplifiers (an application in which controlled distortion is desirable) and low damping can be better. Numerous guitar amplifiers have damping controls, and the trend to include this feature has been increasing since the 1990s. For instance the Marshall Valvestate 8008 rack-mounted stereo amplifier has a switch between "linear" and "Valvestate" mode:
 * "Linear/Vstate selector. Slide to select linear or Valvestate performance. The Valvestate mode gives extra warm harmonics plus the richness of tone, which is unique to the Valvestate power stage. Linear mode produces a highly defined hi-fi tone that gives a totally different character to the sound and suits certain modern "metal" styles, or PA applications."

This is actually a damping control based on negative current feedback, which is evident from the schematic, where the same switch is labeled as "Output Power Mode: Current/Voltage".

title: Damping factor


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Junkers Jumo 223

The Junkers Jumo 223 was an experimental 24-cylinder aircraft engine based on the Junkers Jumo 205. Like the Jumo 205, it was an opposed piston two-stroke diesel engine. It had four banks of six cylinders in a rhomboid configuration, with four crankshafts, one at each vertex of the rhombus, and 48 pistons. It was designed for a power of 2,500 horsepower at 4,400 rpm, and weighed around 2,370 kg.

Only one example is known to have been built. It is rumoured to have been taken to Moscow at the end of World War II, where development may have continued.

Jumo 224
In 1942 the 223 was abandoned in favour of an even larger engine, the Jumo 224 with an intended output power of 4,500 horsepower.

The Jumo 223 series was influential to the successful three-crankshaft Napier Deltic engine.

title: Junkers Jumo 223


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Critical section

In concurrent programming, concurrent accesses to shared resources can lead to unexpected or erroneous behavior. Thus, the parts of the program where the shared resource is accessed need to be protected in ways that avoid the concurrent access. One way to do so is known as a critical section or critical region. This protected section cannot be entered by more than one process or thread at a time; others are suspended until the first leaves the critical section. Typically, the critical section accesses a shared resource, such as a data structure, peripheral device, or network connection, that would not operate correctly in the context of multiple concurrent accesses.

Need for critical sections
Different codes or processes may consist of the same variable or other resources that must be read or written but whose results depend on the order in which the actions occur. For example, if a variable x is to be read by process A, and process B must write to the variable x at the same time, process A might get either the old or new value of x.

Process A: Process B:

In cases where a locking mechanism with finer granularity is not needed, a critical section is important. In the above case, if A needs to read the updated value of x, executing process A, and process B at the same time may not give required results. To prevent this, variable x is protected by a critical section. First, B gets the access to the section. Once B finishes writing the value, A gets the access to the critical section, and variable x can be read.

By carefully controlling which variables are modified inside and outside the critical section, concurrent access to the shared variable are prevented. A critical section is typically used when a multi-threaded program must update multiple related variables without a separate thread making conflicting changes to that data. In a related situation, a critical section may be used to ensure that a shared resource, for example, a printer, can only be accessed by one process at a time.

Implementation of critical sections
The implementation of critical sections vary among different operating systems.

A critical section will usually terminate in finite time, and a thread, task, or process must wait for a fixed time to enter it (bounded waiting). To ensure exclusive use of critical sections, some synchronization mechanism is required at the entry and exit of the program.

A critical section is a piece of a program that requires mutual exclusion of access.

As shown in the figure, in the case of mutual exclusion (mutex), one thread blocks a critical section by using locking techniques when it needs to access the shared resource, and other threads must wait their turn to enter the section. This prevents conflicts when two or more threads share the same memory space and want to access a common resource.

The simplest method to prevent any change of processor control inside the critical section is implementing a semaphore. In uniprocessor systems, this can be done by disabling interrupts on entry into the critical section, avoiding system calls that can cause a context switch while inside the section, and restoring interrupts to their previous state on exit. With this implementation, any execution thread entering any critical section in the system will prevent any other thread, including an interrupt, from being granted processing time on the CPU until the original thread leaves its critical section.

This brute-force approach can be improved by using semaphores. To enter a critical section, a thread must obtain a semaphore, which it releases on leaving the section. Other threads are prevented from entering the critical section at the same time as the original thread, but are free to gain control of the CPU and execute other code, including other critical sections that are protected by different semaphores. Semaphore locking also has a time limit to prevent a deadlock condition in which a lock is acquired by a single process for an infinite time, stalling the other processes that need to use the shared resource protected by the critical section.

Kernel-level critical sections
Typically, critical sections prevent thread and process migration between processors and the preemption of processes and threads by interrupts and other processes and threads.

Critical sections often allow nesting. Nesting allows multiple critical sections to be entered and exited at little cost.

If the scheduler interrupts the current process or thread in a critical section, the scheduler will either allow the currently executing process or thread to run to completion of the critical section, or it will schedule the process or thread for another complete quantum. The scheduler will not migrate the process or thread to another processor, and it will not schedule another process or thread to run while the current process or thread is in a critical section.

Similarly, if an interrupt occurs in a critical section, the interrupt information is recorded for future processing, and execution is returned to the process or thread in the critical section. Once the critical section is exited, and in some cases the scheduled quantum completed, the pending interrupt will be executed. The concept of scheduling quantum applies to "round-robin" and similar scheduling policies.

Since critical sections may execute only on the processor on which they are entered, synchronization is only required within the executing processor. This allows critical sections to be entered and exited at almost no cost. No inter-processor synchronization is required. Only instruction stream synchronization is needed. Most processors provide the required amount of synchronization by interrupting the current execution state. This allows critical sections in most cases to be nothing more than a per processor count of critical sections entered.

Performance enhancements include executing pending interrupts at the exit of all critical sections and allowing the scheduler to run at the exit of all critical sections. Furthermore, pending interrupts may be transferred to other processors for execution.

Critical sections should not be used as a long-lasting locking primitive. Critical sections should be kept short enough so they can be entered, executed, and exited without any interrupts occurring from the hardware and the scheduler.

Kernel-level critical sections are the base of the software lockout issue.

Critical sections in data structures
In parallel programming, the code is divided into threads. The read-write conflicting variables are split between threads and each thread has a copy of them. Data structures such as linked lists, trees, and hash tables have data variables that are linked and cannot be split between threads; hence, implementing parallelism is very difficult. To improve the efficiency of implementing data structures, multiple operations such as insertion, deletion, and search can be executed in parallel. While performing these operations, there may be scenarios where the same element is being searched by one thread and is being deleted by another. In such cases, the output may be erroneous. The thread searching the element may have a hit, whereas the other thread may subsequently delete it. These scenarios will cause issues in the program running by providing false data. To prevent this, one method is to keep the entire data structure under critical section so that only one operation is handled at a time. Another method is locking the node in use under critical section, so that other operations do not use the same node. Using critical section, thus, ensures that the code provides expected outputs.

Critical sections in relation to peripherals
Critical sections also occur in code which manipulates external peripherals, such as I/O devices. The registers of a peripheral must be programmed with certain values in a certain sequence. If two or more processes control a device simultaneously, neither process will have the device in the state it requires and incorrect behavior will ensue.

When a complex unit of information must be produced on an output device by issuing multiple output operations, exclusive access is required so that another process does not corrupt the datum by interleaving its own bits of output.

In the input direction, exclusive access is required when reading a complex datum via multiple separate input operations. This prevents another process from consuming some of the pieces, causing corruption.

Storage devices provide a form of memory. The concept of critical sections is equally relevant to storage devices as to shared data structures in main memory. A process which performs multiple access or update operations on a file is executing a critical section that must be guarded with an appropriate file locking mechanism.

title: Critical section


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Supermajority

A supermajority (also called supra-majority, supramajority, qualified majority, or special majority) is a requirement for a proposal to gain a specified level of support which is greater than the threshold of more than one-half used for a simple majority. Supermajority rules in a democracy can help to prevent a majority from eroding fundamental rights of a minority, but they can also hamper efforts to respond to problems and encourage corrupt compromises at times when action is taken. Changes to constitutions, especially those with entrenched clauses, commonly require supermajority support in a legislature. Parliamentary procedure requires that any action of a deliberative assembly that may alter the rights of a minority have a supermajority requirement, such as a two-thirds vote. In consensus democracy the supermajority rule is applied in most cases.

Related concepts regarding alternatives to the majority vote requirement include a majority of the entire membership and a majority of the fixed membership. A supermajority can also be specified on the basis of the entire membership or fixed membership rather than on those present and voting.

History
The first known use of a supermajority rule was in the 100s BC in ancient Rome.

Pope Alexander III introduced the use of supermajority rule for papal elections at the Third Lateran Council in 1179.

In the Democratic Party of the United States, a rule requiring the determination of a presidential nominee required the votes of two-thirds of delegates to the Democratic National Convention was adopted at the party's first presidential nominating convention in 1832. The two-thirds rule gave southern Democrats a de facto veto over any presidential nominee after the Civil War, which lasted until the rule was abolished in 1936.

In the Federalist Papers, Alexander Hamilton and James Madison were critical of supermajority requirements. In Federalist 22, Hamilton wrote that while preventing harmful legislation from being passed, such requirements also prevented beneficial legislation from being passed, and "its real operation is to embarrass the administration, to destroy the energy of government, and to substitute the pleasure, caprice or artifices of an insignificant, turbulent or corrupt junto, to the regular deliberations and decisions of a respectable majority." Hamilton also wrote that such a requirement would encourage "contemptible compromises of the public good". In Federalist 58, Madison wrote that supermajority requirements might help impede the passage of "hasty and partial measures", but "[i]n all cases where justice or the general good might require new laws to be passed, or active measures to be pursued, the fundamental principle of free government would be reversed. It would be no longer the majority that would rule; the power would be transferred to the minority." Madison also wrote that such requirements would encourage secession.

Common supermajorities
A majority vote, or more than half the votes cast, is a common voting basis. Instead of the basis of a majority, a supermajority can be specified using any fraction or percentage which is greater than one-half. It can also be called a qualified majority. Common supermajorities include three-fifths (3/5–60%), two-thirds (2/3–66.66...%), and three-quarters (3/4–75%).

Two-thirds, or $66 2⁄3$ percent
A two-thirds vote, when unqualified, means two-thirds or more of the votes cast. This voting basis is equivalent to the number of votes in favour being at least twice the number of votes against. Abstentions and absences are excluded in calculating a two-thirds vote.

The two-thirds requirement can be qualified to include the entire membership of a body instead of only those present and voting, but such a requirement must be explicitly stated (such as "two-thirds of those members duly elected and sworn"). In this case, abstentions and absences count as votes against the proposal. Alternatively, the voting requirement could be specified as "two-thirds of those present", which has the effect of counting abstentions but not absences as votes against the proposal.

For example, if an organization has 150 members and at a meeting 30 members are present with 25 votes cast, a "two-thirds vote" would be 17. ("Two-thirds of those present" would be 20, and "two-thirds of the entire membership" would be 100.)

Three-fifths, or 60 percent
Another type of supermajority is three-fifths (60 percent). This requirement could also be qualified to include the entire membership or to include those present.

In 2006, the Constitution of Florida was amended to require a 60% majority to pass new constitutional amendments by popular vote.

In Poland, the Sejm (lower house of the bicameral parliament of Poland) requires a three-fifths majority of MPs to overturn a veto from the President of Poland.

55 percent
For the Montenegrin independence referendum held in 2006 the European Union envoy Miroslav Lajčák proposed independence if a 55% supermajority of votes are cast in favor with a minimum turnout of 50%. Such procedure, ultimately accepted by the government of Montenegro, was somewhat criticized as overriding the traditional practice of requiring a two-thirds supermajority, as practiced in all former Yugoslav countries before (including the previous referendum in Montenegro).

In 2016, the Constitution of Colorado was amended to require a 55% majority to pass new constitutional amendments by popular vote. It had previously been a simple majority.

Related concepts
Related concepts regarding alternatives to the majority vote requirement include a "majority of the entire membership" and a "majority of the fixed membership".

Majority of the entire membership
A majority of the entire membership is a voting basis that requires that more than half of all the members of a body (including those absent and those present but not voting) vote in favor of a proposition in order for it to be passed. In practical terms, it means an absence or an abstention from voting is equivalent to a "no" vote. It may be contrasted with a majority vote which only requires more than half of those actually voting to approve a proposition for it to be enacted. An absolute majority may also be the same as a majority of the entire membership, although this usage is not consistent.

A supermajority could be specified in this voting basis, such as a vote of "two-thirds of the entire membership". By way of illustration, in February 2007 the Italian Government fell after it lost a vote in the Italian Senate by 158 votes to 136 (with 24 abstentions). The government needed an absolute majority in the 318-member house but fell two votes short of the required 160 when two of its own supporters abstained. In the United States Electoral College, an absolute majority of electoral votes are required for it to elect the US president and vice-president.

Majority of the fixed membership
A majority of the fixed membership is based on the total number of the established fixed membership of the deliberative assembly. It is used only when a specific number of seats or memberships is established in the rules governing the organization. A majority of the fixed membership would be different from a majority of the entire membership if there are vacancies.

For example, say a board has 12 seats. If the board has the maximum number of members, or 12 members, a majority of the entire membership and a majority of the fixed membership would be seven members. However, if there are two vacancies (so that there are only ten members on the board), then a majority of the entire membership would be six members (more than half of ten), but a majority of the fixed membership would still be seven members.

It is possible for organizations that use a majority of the fixed membership to be caught in a stalemate if at least half the membership consists of vacancies, making it impossible to perform any actions until those vacancies are filled. The requirement for a minimum number of members to be present in order to conduct business, called a quorum, may be used to avoid such a possibility.

Similar to the voting basis for the entire membership, a supermajority could be specified for this basis, such as a vote of "two-thirds of the fixed membership".

Use in parliamentary procedure
Parliamentary procedure requires that any action that may alter the rights of a minority have a supermajority requirement. Robert's Rules of Order states: "As a compromise between the rights of the individual and the rights of the assembly, the principle has been established that a two-thirds vote is required to adopt any motion that: (a) suspends or modifies a rule of order previously adopted; (b) prevents the introduction of a question for consideration; (c) closes, limits, or extends the limits of debate; (d) closes nominations or the polls, or otherwise limits the freedom of nominating or voting; or (e) takes away membership."This book also states: "The vote of a majority of the entire membership is frequently an alternative to a requirement of previous notice, and is required in order to rescind and expunge from the minutes (see p. 310). Otherwise, prescribing such a requirement is generally unsatisfactory in an assembly of an ordinary society, since it is likely to be impossible to get a majority of the entire membership even to attend a given meeting, although in certain instances it may be appropriate in conventions or in permanent boards where the members are obligated to attend the meetings."

Australia
To pass an amendment to the Australian Constitution, a referendum is required and must achieve a "double majority": a majority of those voting nationwide, as well as separate majorities in a majority of states (i.e., 4 out of 6 states). Furthermore, in circumstances where a specific state is affected by a referendum, a majority of voters in that state must also agree to the change —referred to as a "triple majority".

Bangladesh
Article 142 of the Constitution of Bangladesh stipulates a bill in the Jatiya Sangsad must expressly state in its short title its purpose is to amend a provision of the constitution. Constitutional amendments require a two-thirds majority in the unicameral Jatiya Sangsad to become effective.

Canada
In Canada, most constitutional amendments can be passed only if identical resolutions are adopted by the House of Commons, the Senate and two-thirds or more of the provincial legislative assemblies representing at least 50 percent of the national population.

Denmark
Article 20 of the Constitution of Denmark states that if the government or parliament wants to cede parts of national sovereignty to an international body such as the European Union or the United Nations, it has to get a five-sixths majority in the Folketing (150 out of 179 seats). If there is only a simple majority, a referendum must be held on the subject.

Council
The Council of the European Union uses 'Qualified majority voting' for the majority of issues brought before the institution. However, for matters of extreme importance for individual member states, unanimous voting is implemented. An example of this is Article 7 of the Treaty on European Union, whereby a member state can have its rights suspended with the unanimous approval of all other member states.

After the accession of Croatia, on 1July 2013, at least 260 votes out of a total of 352 by at least 15 member states were required for legislation to be adopted by qualified majority. From 1July 2013, the pass condition translated into:
 * 1) At least 15 (or 18, if proposal was not made by the commission) countries,
 * 2) At least 260 of the total 352 voting weights,
 * 3) At least 313.6 million people represented by the states that vote in favour.

Parliament
Requirements to reach an absolute majority is a common feature of voting in the European Parliament (EP) where under the ordinary legislative procedure the EP is required to act by an absolute majority if it is to either amend or reject proposed legislation.

Finland
According to Finnish Law, when a new legislative proposal would in some way add, alter or remove a part of the Finnish constitution, a bill requires a 2/3 majority in the Parliament of Finland. In other words, a legislative proposal that would modify, add or remove a part of the Finnish Constitution requires at least the approval of 134 out of 200 representatives in the Parliament of Finland

India
Article 368 of the Indian Constitution requires a supermajority of two-thirds of members present and voting in each house of the Indian Parliament, subject to at least by a majority of the total membership of each House of Parliament, to amend the constitution. In addition, in matters affecting the states and judiciary, at least above half of all the states need to ratify the amendment.

Italy
The President of Italy is elected by an electoral college consisting of both chambers of Parliament sitting in joint session with 58 electors from the country's 20 regions. In the first three rounds of voting, a candidate must get two-thirds of the votes to win, but from the fourth round onwards only an absolute majority is needed. Reforms to the Constitution need to achieve a supermajority of two-thirds of the votes both in the Chamber and in the Senate to avoid the possibility of being sent to popular vote in order to be confirmed through a referendum.

Japan
Amendments to the constitution require a two-thirds majority in both houses of the National Diet and a simple majority in a referendum.

New Zealand
Section 268 of the Electoral Act sets out a number of 'reserved provisions'. These provisions include section 17(1) of the Constitution Act 1986 (regarding Parliament's term length), section 35 of the Electoral Act (regarding the drawing of electoral boundaries), and section 74 of the Electoral Act (designating 18 as the minimum voting age). For a 'reserved provision' to be amended or repealed, a three-quarters majority is required in the House of Representatives or a majority is needed in a national referendum.

Nigeria
Under the Constitution of Nigeria a two-thirds majority is required in the National Assembly to alter the Constitution, enact legislation in a few areas, or remove office holders from some positions, such as Speaker. Legislative override or impeachment of the executive at either the state or federal government level also requires a two-thirds majority of the corresponding legislative assembly.

Philippines
Under the 1987 Constitution of the Philippines, a two-thirds majority of both chambers of the Congress of the Philippines (the House of Representatives and the Senate) meeting in joint session is required to declare war. A two-thirds majority of both chambers is required to override a presidential veto. A two-thirds vote of both chambers of Congress voting separately is required to designate the vice president as acting president in the event that a majority of the Cabinet certifies that the president is "unable to discharge the powers and duties of his office" but the president declares that no such inability exists. A two-thirds vote of either chamber is required to suspend or expel a member from that chamber.

Under the 1987 Constitution, "The Congress may, by a vote of two-thirds of all its Members, call a constitutional convention, or by a majority vote of all its Members, submit to the electorate the question of calling such a convention." A three-quarters vote of all the members of the Congress is required to propose an amendment to the Constitution; the proposed amendment is submitted to the people for ratification (by a majority of the votes cast) in a plebiscite.

A two-thirds majority of the Senate is required to ratify treaties, and to remove an impeached official from office. Impeachment by the House, which is the required first step in the removal process, only requires one-third of Representatives to sign a petition (specifically a verified complaint or resolution of impeachment).

Singapore
Different amendment procedures apply to different parts of the Constitution. Most of the Articles of the Constitution may be amended by a bill enacted by Parliament if there is at least a supermajority of two-thirds of all elected MPs voting in favour of the bill during its Second and Third Readings in Parliament. This is in contrast to ordinary bills, which only need to be approved by at least a simple majority of all the MPs present and voting.

However, the ruling People's Action Party (PAP) has commanded a majority of more than two-thirds of the seats in Parliament since 1968. Thus, the more stringent amendment requirement has not imposed any major limitation on Parliament's ability to amend the Constitution.

Legislation
A three-fifths majority of legislators is required for a bill to be put to a vote in the National Assembly in order to prevent the ruling party from passing laws without the support of opposition parties. However, if a bill does not achieve the required three-fifths majority at one session without also being rejected, it must then be voted on at the next session even if less than three-fifths of legislators agree to do so.

Additionally, if the President vetoes a bill, the veto can be overridden by a two-thirds majority of legislators.

Impeachment
According to Article 65 of the Constitution of South Korea, impeachment of the President requires a two-third majority of legislators to be effective.

Judicial review
According to Article 113 of the Constitution of South Korea, the Constitutional Court requires a two-thirds majority of its judges to issue rulings nullifying laws, removing impeached officials or dissolving a political party.

Constitutional amendments
According to Article 130 of the Constitution of South Korea, amendments to the constitution must be passed by a two-thirds majority of legislators and then approved by voters at a referendum in order to become effective.

Constitutional reform
The 1978 Constitution states that a three-fifths majority in both Congress of Deputies and Senate of Spain is needed to pass a constitutional reform, but if a two-thirds majority is reached in the Congress of Deputies, an absolute majority of senators is enough to pass the proposal.

Nevertheless, when a new Constitution is proposed or the proposal's goal is to reform the Preliminary Title, the Chapter on Fundamental Rights and Freedoms or the Title on the Crown, the supermajority becomes significantly harder:
 * A supermajority of two-thirds must be reached in both Congress of Deputies and Senate.
 * Both chambers must be dissolved.
 * The new elected chambers must approve the proposal by a new two-thirds supermajority.
 * Finally, the proposal is passed by majority in referendum.

The first way has been used twice (1992 and 2011), but the second has never been used.

Other legal procedures
The Spanish Constitution states other supermajorities:
 * Members of the General Council of the Judiciary are appointed by the Congress of Deputies and Senate of Spain, and each appointment needs a three-fifths majority.
 * Members of the Constitutional Court are also appointed by both Congress of Deputies and Senate of Spain, and each appointment needs a three-fifths majority.
 * The president of the RTVE, the public radio and television broadcaster, must be elected by two-thirds majority of the Congress of Deputies.

Autonomous communities
Each Spanish autonomous community has its own Statute of Autonomy, working like a local constitution that is subject to the 1978 Constitution and national powers.

The Statute of Autonomy of the Canary Islands states that its economic and fiscal regime and electoral law need a two-thirds majority of the Parliament to be modified. On its behalf, the Ombudsman needs a three-fifths majority to be appointed. Also, if a two-thirds majority votes against a law project, it must be proposed to the following session.

Taiwan
Before the Additional Articles of the Constitution of the Republic of China in 2005, the constitution amendments need to be passed by the National Assembly. Since the Additional Articles ratified on June 7, 2005, the National Assembly was abolished. Amendments of the constitution need to be proposed by more than one-quarter of members of the Legislative Yuan, passed by three-quarters of those present in the meeting, the presence of which must surpass three-quarters of all members of Legislative Yuan, then followed by approval by more than half (50%) of all eligible voters in referendums.

Turkey
In Turkey, constitutional amendments need a three fifths majority (360 votes) to be put forward to a referendum and a two-thirds majority (400 votes) to be ratified directly.

Constitutional amendments
According to Article 155 of the Constitution of Ukraine, amendments to the constitution, except for Chapter I — "General Principles," Chapter III — "Elections. Referendum", and Chapter XIII — "Introducing Amendments to the Constitution of Ukraine", must be previously approved by a simple majority of the constitutional composition of the Verkhovna Rada of Ukraine and then passed by a two-thirds majority of the constitutional composition of the Verkhovna Rada of Ukraine at the succeeding regular session of the Verkhovna Rada of Ukraine.

According to Article 156 of the Constitution of Ukraine, amendments to Chapter I — "General Principles," Chapter III — "Elections. Referendum", and Chapter XIII — "Introducing Amendments to the Constitution of Ukraine" must be passed by a two-thirds majority of the constitutional composition of the Verkhovna Rada of Ukraine and then approved by voters at a referendum in order to become effective.

UK Parliament
A rare example of a supermajority requirement affecting the Parliament of the United Kingdom is the need for a two-thirds supermajority vote in both the House of Commons and the House of Lords to amend or dissolve the Royal Charter on self-regulation of the press, insofar as it applies in England and Wales.

Before its repeal, the Fixed-term Parliaments Act 2011 provided that the United Kingdom House of Commons could be dissolved and an election held before the expiry of its 5-year term by a vote of two-thirds of the membership of the House of Commons. The Act also provided that Parliament could alternatively be dissolved if the House of Commons passed a motion of no-confidence in the government and no new government were to win a motion of confidence within two weeks of the original vote of no-confidence.

The two-thirds supermajority provision for an early dissolution and election was triggered only once, resulting in the 2017 United Kingdom General Election. The previous election in 2015 had occurred due to the natural expiry of the 5-year term of the House of Commons.

Parliamentary supremacy meant that theoretically the Act could be circumvented by a government with a majority that wanted to bypass the requirement for a two-thirds vote by passing an act that stated, "Notwithstanding the Fixed-term Parliaments Act 2011, a general election will be called on DATE". This was precisely what was done to initiate the election in 2019, the final election held whilst the Fixed-term Parliaments Act was in effect.

During the 2019 election, both the governing Conservative Party and the opposition Labour Party expressed a desire to repeal the Fixed-term Parliaments Act and restore the traditional, centuries-old system under which elections could be held at any time, subject to the 5-year maximum term limit established by the Parliament Act 1911. Such a repeal would only require a simple majority.

Ultimately, the Fixed-term Parliaments Act was repealed by the Dissolution and Calling of Parliament Act 2022, thereby removing any supermajority requirement and restoring the previous royal prerogative power to dissolve the House of Commons at any time during its 5-year term.

Devolved parliaments
The devolved legislatures in Northern Ireland, Scotland and Wales all usually operate with fixed intervals between ordinary elections. However, the acts governing the operation of those legislatures all allow for an early election to take place if a motion to that effect is approved by two-thirds of the total number of members of the legislature in question.

Section 31A of the Scotland Act 1998 and Section 111A of the Government of Wales Act 2006 provide that certain provisions of those Acts relating to the functions of and elections to the respective Scottish and Welsh devolved legislatures are protected from amendment by those legislatures, unless a two-thirds supermajority of the total number of members votes in favour.

Regarding Scotland, the protected provisions are:
 * Who may vote at Scottish Parliament elections
 * The system of election for members of the Scottish Parliament
 * The number of Scottish Parliament constituencies
 * The number of members returned by each constituency

The protected provisions regarding Wales are the same as those in Scotland; in addition, there are two Wales-specific provisions:
 * The name of the legislature
 * The number of individuals permitted to be appointed Welsh Minister or Deputy Welsh Minister

A two-thirds supermajority vote is required in the Scottish Parliament in order to amend or dissolve the Royal Charter on self-regulation of the press, insofar as it applies in Scotland.

Local authorities
Local authorities in Wales are required to pass a resolution with a two-thirds supermajority vote in order to change the system by which they are elected, with the permitted choices being first-past-the-post and single transferable vote.

District councils in England are required to pass a resolution with a two-thirds supermajority vote in order to change their 'electoral scheme,' i.e. what proportion of councillors is elected at each ordinary election, with permitted proportions being one-third, one-half or all councillors.

The London Assembly may, by a two-thirds supermajority vote, veto the mayor's draft strategies.

United Nations
The United Nations Security Council requires a supermajority of the fixed membership on substantive matters (procedural matters require a simple majority of those present and voting). According to Article 27 of the United Nations Charter, at least nine of the Security Council's 15 members (i.e., a three-fifths supermajority) must vote in favor of a draft resolution in order to achieve passage. Specifying the fixed membership has the effect of making abstentions count as votes against—absences are not normal but would be treated the same way.

This is useful for the five permanent members of the council (China, France, the Russian Federation, the United Kingdom, and the United States) because a vote against from any one of them constitutes a veto, which cannot be overridden. Permanent members who do not support a measure but are unwilling to be seen to block it against the wishes of the majority of the council, tend to abstain; abstentions by veto powers are generally seen by close observers of the UN as the equivalent of not vetoing votes against and have the same impact on the decision of the Security Council.

Federal government
The Constitution of the United States requires supermajorities in order for certain significant actions to occur.

Amendments to the Constitution may be proposed in one of two ways: a two-thirds supermajority votes of each body of United States Congress or a convention called by Congress on application of two-thirds (currently 34) of the states. Once proposed, the amendment must be ratified by three-quarters (currently 38) of the states (either through the state legislatures, or ratification conventions, whichever "mode of ratification" Congress selects).

Congress may pass bills by simple majority votes. If the president vetoes a bill, Congress may override the veto by a two-thirds supermajority of both houses.

A treaty must be ratified by a two-thirds supermajority of the Senate to enter into force and effect.

Section 4 of the Twenty-fifth Amendment to the United States Constitution gives Congress a role to play in the event of a presidential disability. If the vice president and a majority of the president's cabinet declare that the president is unable to serve in that role, the vice president becomes acting president. Within 21 days of such a declaration (or, if Congress is in recess when a president is disabled, 21 days after Congress reconvenes), Congress must vote by two-thirds supermajorities to continue the disability declaration; otherwise, such declaration expires after the 21 days and the president would at that time "resume" discharging all the powers and duties of the office. As of 2024, Section 4 has never been invoked.

The House may, by a simple majority vote, impeach a federal official (such as, but not limited to, the president, vice president, or a federal judge). Removal from office requires a two-thirds supermajority of the Senate. In 1842, the House failed to impeach president John Tyler. In 1868, the Senate fell one vote short of removing president Andrew Johnson following his impeachment. In 1999, efforts to remove Bill Clinton following his impeachment in 1998 fell just short of a simple majority, and 17 votes short of the two-thirds supermajority. The impeachment procedure was last used in 2021, when former president Donald Trump was impeached for a second time and subsequently acquitted. Each chamber may expel one of its own members by a two-thirds supermajority vote; this last happened when the House expelled George Santos in 2023.

The 14th Amendment (section 3) bars a person from federal or state office if, after having previously taken an oath to support the Constitution as a federal or state officer, "shall have engaged in insurrection or rebellion against the same, or given aid or comfort to the enemies thereof". However, both the House and Senate may jointly override this restriction with a two-thirds supermajority vote each.

A two-thirds supermajority in the Senate is 67 out of 100 senators, while a two-thirds supermajority in the House is 290 out of 435 representatives. However, since many votes take place without every seat in the House filled and representative participating, it does not often require 67 senators or 290 representatives to achieve this supermajority.

Apart from these constitutional requirements, a Senate rule (except in cases covered by the nuclear option, or of a rule change) requires an absolute supermajority of three-fifths to move to a vote through a cloture motion, which closes debate on a bill or nomination, thus ending a filibuster by a minority of members. In current practice, the mere threat of a filibuster prevents passing almost any measure that has less than three-fifths agreement in the Senate, 60 of the 100 senators if every seat is filled.

State government
For state legislatures in the United States, Mason's Manual says, "A deliberative body cannot by its own act or rule require a two-thirds vote to take any action where the constitution or controlling authority requires only a majority vote. To require a two-thirds vote, for example, to take any action would be to give to any number more than one-third of the members the power to defeat the action and amount to a delegation of the powers of the body to a minority." Some states require a supermajority for passage of a constitutional amendment or statutory initiative.

Many state constitutions allow or require amendments to their own constitutions to be proposed by supermajorities of the state legislature; these amendments must usually be approved by the voters at one or more subsequent elections. Michigan, for instance, allows the Legislature to propose an amendment to the Michigan Constitution; it must then be ratified by the voters at the next general election (unless a special election is called).

In most states, the state legislature may override a governor's veto of legislation. In most states, a two-thirds supermajority of both chambers is required. However, in some states (e.g., Illinois, Maryland and North Carolina), only a three-fifths supermajority is required,  while in Kentucky and West Virginia only a normal majority is needed.

One common provision of so-called "taxpayer bill of rights" laws (either in state statutes or state constitutions) is requirement of a supermajority vote in the state legislature to increase taxes. The National Conference of State Legislatures reported in 2010 that fifteen states required a supermajority vote (either a three-fifths, two-thirds or three-quarters majority vote in both chambers) to pass some or all tax increases.

Supermajority requirements for tax increases have been criticized as "deeply flawed" by a report by the progressive Center on Budget and Policy Priorities because such requirements empower a minority of legislators, making it difficult to close tax loopholes or fund transportation infrastructure, and also may encourage pork-barrel spending as a trade-off to ensure passage of a tax increase (see logrolling).

International agreements
The Rome Statute requires a seven-eighths majority of participating states to be amended.

title: Supermajority


text:
Postmaster General of Canada

The Postmaster General of Canada was the Canadian cabinet minister responsible for the Post Office Department (Canada Post). In 1851, management of the post office was transferred from Britain (Royal Mail) to the provincial governments of the Province of Canada, New Brunswick, Newfoundland, Nova Scotia and Prince Edward Island. The position of Postmaster General was established in each province. With Canadian Confederation in 1867, a single position was created replacing this post in all of the above provinces except Newfoundland; this position was abolished in 1981 when the post office was transformed from a government department into a crown corporation. Since 1981 Canada Post has been led by a President and CEO. From 1900 until 1909 the Postmaster General was also responsible for the Department of Labour. It now reports to the Minister of Public Services and Procurement.

Postmasters General

 * Alexander Campbell
 * under MacDonald (July 1, 1867 – June 30, 1873)

 * John O'Connor
 * under Macdonald (July 1, 1873 – November 5, 1873)

 * Donald Alexander Macdonald
 * under MacKenzie (November 7, 1873 – May 17, 1875)

 * Télesphore Fournier
 * under Mackenzie (May 19, 1875 – October 7, 1875)

 * Lucius Seth Huntington
 * under Mackenzie (October 9, 1875 – October 8, 1878)

 * Hector Louis Langevin
 * under Macdonald (October 19, 1878 – May 19, 1879)

 * Sir Alexander Campbell
 * under Macdonald (May 20, 1879 – January 15, 1880) (second time)

 * John O'Connor
 * under Macdonald (January 16, 1880 – November 7, 1880) (second time)

 * Sir Alexander Campbell
 * under Macdonald (November 8, 1880 – May 18, 1881) (third time)

 * John O'Connor
 * under Macdonald (May 20, 1881 – May 22, 1882) (third time)

 * John Carling
 * under Macdonald (May 23, 1882 – September 24, 1885)

 * Sir Alexander Campbell
 * under Macdonald (September 25, 1885 – January 26, 1887) (fourth time)

 * Archibald McLelan
 * under Macdonald (January 27, 1887 – July 9, 1888)

 * John Carling
 * under Macdonald (July 11, 1888 – August 5, 1888) (second time)

 * John Graham Haggart
 * under Macdonald (August 6, 1888 – June 6, 1891)
 * under Abbott (June 16, 1891 – January 24, 1892)

 * Sir Joseph Philippe René Adolphe Caron
 * under Abbott (January 25, 1892 – November 24, 1892)
 * under Thompson (December 5, 1892 – December 12, 1894)

 * Louis-Olivier Taillon
 * under Mackenzie Bowell (December 21, 1894 – July 8, 1896)

 * Sir William Mulock
 * under Laurier (July 13, 1896 – October 15, 1905)

 * Allen Bristol Aylesworth
 * under Laurier (October 16, 1905 – June 3, 1906)

 * Rodolphe Lemieux
 * under Laurier (June 4, 1906 – August 10, 1911)

 * Henri Sévérin Béland
 * under Laurier (August 19, 1911 – October 6, 1911)

 * Louis-Philippe Pelletier
 * under Borden (October 10, 1911 – October 19, 1914)

 * Thomas Chase-Casgrain
 * under Borden (October 20, 1914 – December 29, 1916)

 * Pierre Édouard Blondin
 * under Borden (January 8, 1917 – July 10, 1920)
 * under Meighen (July 10, 1920 – September 20, 1921)

 * Louis-de-Gonzague Belley
 * under Meighen (September 21, 1921 – December 29, 1921)

 * Charles Murphy
 * under King (December 29, 1921 – June 28, 1926)

 * Robert James Manion
 * under Meighen (August 23, 1926 – September 25, 1926)

 * Peter John Veniot
 * under King (September 25, 1926 – August 7, 1930)

 * Arthur Sauvé
 * under Bennett (August 7, 1930 – August 13, 1935)

 * Samuel Gobeil
 * under Bennett (August 16, 1935 – October 23, 1935)

 * John Campbell Elliott
 * under King (October 23, 1935 – January 22, 1939)

 * Norman Alexander McLarty
 * under King (January 23, 1939 – September 18, 1939)

 * Charles Gavan Power
 * under King (September 19, 1939 – May 22, 1940)

 * James Lorimer Ilsley
 * (acting)
 * under King (May 23, 1940 – July 7, 1940)

 * William Pate Mulock
 * under King (July 8, 1940 – June 8, 1945)

 * Ernest Bertrand
 * under King (August 29, 1945 – November 15, 1948)
 * under St. Laurent (November 15, 1948 – August 23, 1949)

 * Gabriel Édouard Rinfret
 * under St. Laurent (August 25, 1949 – February 12, 1952)

 * Alcide Côté
 * under St. Laurent (February 13, 1952 – August 7, 1955)

 * Roch Pinard
 * (acting)
 * under St. Laurent (August 16, 1955 – November 2, 1955)

 * Hugues Lapointe
 * under St. Laurent (November 3, 1955 – June 21, 1957)

 * William McLean Hamilton
 * under Diefenbaker (June 21, 1957 – July 12, 1962)

 * John Angus MacLean
 * (acting)
 * under Diefenbaker (July 18, 1962 – August 8, 1962)

 * Ellen Louks Fairclough
 * under Diefenbaker (August 9, 1962 – April 22, 1963)

 * Azellus Denis
 * under Pearson (April 22, 1963 – February 2, 1964)

 * John Robert Nicholson
 * under Pearson (February 2, 1964 – February 14, 1965)

 * René Tremblay
 * under Pearson (February 15, 1965 – December 17, 1965)

 * Joseph Julien Jean-Pierre Côté
 * under Pearson (December 18, 1965 – April 20, 1968)
 * under Trudeau (April 20, 1968 – July 5, 1968)

 * Eric William Kierans
 * under Trudeau (July 5, 1968 – April 28, 1971)

 * Joseph Julien Jean-Pierre Côté
 * under Trudeau (April 29, 1971 – November 26, 1972) (second time)

 * André Ouellet
 * under Trudeau (November 27, 1972 – August 7, 1974)

 * Bryce Stuart Mackasey
 * under Trudeau (August 8, 1974 – September 13, 1976)

 * Jean-Jacques Blais
 * under Trudeau (September 14, 1976 – February 1, 1978)

 * Gilles Lamontagne
 * under Trudeau (February 2, 1978 – June 3, 1979)

 * John Allen Fraser
 * under Clark (June 4, 1979 – March 2, 1980)

 * André Ouellet
 * under Trudeau (March 3, 1980 – October 15, 1981) (second time)

Canada Post Corporation has had its own CEO and President since 1981, who has most of the administrative responsibilities previously exercised by the Postmaster General. With the abolition of the position of Postmaster General the legislative and certain other duties previously exercised by the Postmaster General were transferred to the new position of Minister responsible for Canada Post Corporation.

title: Postmaster General of Canada


text:
Discipline (BDSM)

Discipline in BDSM is the practice in which the dominant sets rules which the submissive is expected to obey. When rules of expected behaviour are broken, punishment is often used as a means of disciplining.

Punishment
In BDSM, rules can be made so that a submissive ("sub") knows how they should behave in order not to displease the dominant. Rules are usually set and agreed upon by the dominant and the submissive before the beginning of any BDSM scene and/or situation, and can also be used to help make the sub feel inferior, or for "training" a novice sub, though such is not always the case and rules can be set by the dominant for reasons both pertaining to the scene (such as fear play) and/or reasons outside of the constructed world of BDSM. When the rules are broken, even accidentally, punishment is often used as a means of discipline. Punishment itself can be physical (e.g. whipping or piercing) or psychological (e.g. erotic humiliation through public nudity or golden showers) or a combination of both (e.g. through predicament bondage).

The goal of discipline is to "teach" (in the context of the BDSM scene, and only as such to make the sub feel inferior by playing as if they are being taught "how to behave" like a child or animal, and such is pretended, as BDSM is sexual play and does not pertain or adhere to reality) the sub how they should behave as well as the consequences that may arise as a result of breaking the rules of behavior. When subs receive punishment for breaking the set rules, they "learn" (again in the context of sexual play) self-restraint and become "better" subs. The punishment is usually, but not always, related to the mistake, and is also usually proportionate to the severity and frequency of the mistake. For example, a punishment for speaking out of turn for the first time may be a simple restraint (such as being silenced using a gag). Similarly, the punishment for a male sub's penis becoming erect despite not being allowed, even if unintentionally, can be a chastity cage.

The sub may also be given the option of choosing his/her own punishment. For example, for a minor mistake made repeatedly, the punishment can be an option either to be caned a few times (physical punishment) or to be paraded nude in public with a pet animal leash (mental punishment). For a major indiscipline by a female sub, the choice can be between breast torture and pussy torture. For a major indiscipline by a male sub, the choice may be the instrument type to be used (e.g. whip or cane) and the body part to be punished (e.g. back or buttocks) with a number of hard strokes.

Punishments carried out on BDSM submissives, even harsh ones involving severe pain, should not be confused with those carried out in sadomasochism, though similar. S&M involves giving pain/torture to a "sub" for the sake of the physical pleasure of the "sub" and/or "dom". In BDSM discipline, punishments given are meant to derive pleasure from the psychological aspect of being inferior, by having to be "taught" and punished like a child or animal, as well as the vulnerability, rejection, and humiliation the "sub" may feel when being punished, and the humility and vulnerability the "sub" may feel after "learning" to overcome their feelings of inferiority and reconcile with the dominant by apologizing and emotionally accepting the punishment for their perceived wrong. One thing the two activities have in common is that there are limits and safewords in both.

Punishments in BDSM are carried out with the consent of both the dominant and the submissive. Such punishments caried out are agreed upon, set up, and talked about before the beginning of a BDSM scene or the signing of any BDSM "slave contract", and the misbehavior of the submissive is also usually predetermined before the activity begins. BDSM is sexual play, and such punishments are not caried out in a real world context, as said before, in that BDSM activities are predetermined, the scenes are made up, and none of it is caried out due to any real misbehavior of the submissive to any actual, real rule. There are "rules" separate from the BDSM scene, such as the safeword being used to signal an unwillingness to continue, and not doing a specific activity, which makes one uncomfortable, and then there are rules in the context of the play which are set to be broken and punished, these are the "play rules". Punishment should also not be confused with BDSM training which may involve giving pain simply in order to increase the endurance limit of the sub. Sometimes, disciplining may avoid punishment altogether, and instead a hard glance or loud voice from the dominant may be effective.

In addition to punishment, disciplining may also involve positive reinforcement. This involves rewarding the sub for good behaviour (e.g. being allowed to sleep on a bed rather than a hard floor).

title: Discipline (BDSM)


text:
Peshwa

Peshwa was second highest office in the Maratha Confederacy, next in rank and prestige only to that of the Chhatrapati. Initially serving as the appointed prime minister in the Maratha Kingdom, the office became hereditary after the death of Shahu in 1749. During the reign of Shahu, the office of Peshwa grew in power and the Peshwas came to be the de facto rulers of the Maratha Confederacy. However following the defeat of the Marathas in 1761, the office of the Peshwa became titular as well and from that point onwards served as the ceremonial head of the Confederacy underneath the Chhatrapati.

All Peshwas during the rule of Shivaji, Sambhaji and Rajaram belonged to Deshastha Brahmin community. The first Peshwa was Moropant Pingle, who was appointed as the head of the Ashta Pradhan (council of eight ministers) by Shivaji, the founder of the Maratha Kingdom. The initial Peshwas were all ministers who served as the chief executives to the king. The later Peshwas held the highest administrative office and also controlled the Maratha confederacy. Under the Chitpavan Brahmin Bhat family, the Peshwas became the de facto hereditary administrators of the Confederacy. The Peshwa's office was most powerful under Baji Rao I (r. 1720–1740). Under Peshwa administration and with the support of several key generals and diplomats, the Maratha Confederacy reached its zenith, ruling major areas of India. The subsequent Peshwas brought in autonomy and as a result later on many states were controlled and administered by the Maratha chiefs such as Scindias and Gaekwads.

In 1760, the peace of Peshwa government was broken by a rising of Kolis under their Naik Javji Bamble. Javji withdrew to the hills and organised a series of gang robberies, causing widespread terror and misery throughout the country. For twenty years he held out bravely, defeating and killing the generals the Peshwa's Government sent against him. At last he was so hotly pursued that, on the advice of Dhondo Gopal, the Peshwa's governor at Nasik, he surrendered all his forts to Tukoji Holkar and, through Holkar's influence, was pardoned and placed in military and police charge of a district of sixty villages with powers of life and death outlaws. In 1798, a fresh disturbance took place among the Kolis. The leader of this outbreak was Ramji Naik Bhangria, who was an abler and more daring man than his predecessors, and succeeded in baffling all the efforts of the Government officers to seize him. As force seemed hopeless, the Government offered Ramji a pardon and gave him an important police post.

First use
The word Peshwa is from Persian pēshwā, meaning "foremost, leader". The term was inherited from the political vocabulary of previous Persianate empires operating in the Deccan. As early as 1397, the Bahmani Sultanate designated its prime minister as "peshwa". In the 16th and 17th centuries, this practice was continued by the Ahmednagar Sultanate and the Bijapur Sultanate, both successor states of the Bahmani Sultanate. After the coronation of Shivaji in 1674, he appointed Moropant Trimbak Pingle as his first Peshwa. Shivaji renamed this designation as Pantpradhan in 1674 but this term was less commonly used. Moropant Trimbak Pingale's son, Nilopant Moreshvar Pingale, succeeded him during Sambhaji's rule after Moropant Pingle's death in 1683.

Ramchandra Pant Amatya (Bawadekar)
Ramchandra Amatya recaptured many forts from the Mughals between 1690 and 1694, some in person, as well as personally conducting guerilla war techniques. When Rajaram I fled to Jinji in 1689, before leaving Maharashtra, he gave "Hukumat panha" (King Status) to Pant. Ramchandra Pant managed the entire state under many challenges such as the Mughal influx, the betrayal of Vatandars, and scarcity of food. With his help, Sachiv kept the Maratha State on a sound economic footing.

Bhat Family
The Maratha war of succession between Tara Bai and Shahu resulted in latter's victory and assumption of Maratha throne as Chhatrapati. In 1713, Shahu appointed Balaji Vishwanath (Bhat), as Peshwa. The appointment of Balaji's son, Baji Rao I, as Peshwa in 1719 by Shahu made the position hereditary in the Bhat family. Baji Rao proved his loyalty by controlling the feudal chieftains who wanted independence from the Maratha Empire. The rebellion of General Trimbak Rao Dabhade, the senapati (commander in chief), over Chauthai (revenue collection) of Gujarat is one example of such internal Maratha feuds. The followers of Baji and Trimbak clashed at the Battle of Bilhapur on 1 April 1731, and Trimbak was killed. In gratitude, Shahu gave the Peshwas and the Bhat family unchallenged control over Maratha empire. who also appointed Baji Rao's son as Peshwa in 1740, gave considerable authority to the Peshwas to command the Maratha armies, and they responded well during his reigns.

At the time of his death in 1749, Shahu made the Peshwas his successors under these conditions: Shivaji's descendants, who remained as the titular Raja of Satara, were called Swami (Marathi for the 'real owner') by the Peshwas who reported to them, and officially they were to seek guidance from the Raja. However, the Peshwa also became a ceremonial head of state after the battle of Panipat and the death of Madhavrao.

Legacy
The first Peshwa to receive the status of a pantpradhan was Ramchandra Pant Amatya Bawdekar in 1689 by Rajaram. The first (Bhat) Deshmukh family Peshwa was Balaji Vishwanath (Bhat) Deshmukh. He was succeeded as Peshwa by his son Baji Rao I, who never lost a battle. Baji Rao and his son, Balaji Baji Rao, oversaw the period of greatest Maratha expansion, brought to an end by the Marathas' defeat by an Afghan army at the Third Battle of Panipat in 1761. The last Peshwa, Baji Rao II, was defeated by the British East India Company in the Battle of Khadki which was a part of Third Anglo-Maratha War (1817–1818). The Peshwa's land (Peshwai) was annexed to the British East India Company's Bombay province, and Bajirao II, the Peshwa was pensioned off.

Notable generals and diplomats

 * Khando Ballal Chitnis
 * Javji Bamble
 * Annaji Datto Sachiv
 * Balaji Kunjar
 * Bapu Gokhale
 * Govind Pant Bundela
 * Ibrahim Khan Gardi
 * Mahadaji Shinde
 * Malhar Rao Holkar
 * Nana Phadnawis
 * Niranjan Madhav Parasnis
 * Parshuram Pant Pratinidhi
 * Sakharam Hari Gupte
 * Pilaji Rao Gaekwad
 * Ranoji Scindia
 * Sadashivrao Bhau
 * Santaji Ghorpade
 * Shamsher Bahadur
 * Visaji Krushna Biniwale

In popular culture

 * Kaustubh Kasture has written a book in marathi titled "Peshwai-Maharashtrachya Itihasatil Ek Suvarnapan" based on Peshwai.
 * Pramod Oak has written a book in marathi titled "Peshwe Gharanyacha Itihas" where he gave detailed information about Peshwas of Bhat family.

title: Peshwa