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Smirnoff

Smirnoff is a brand of vodka owned and produced by the British company Diageo. The Smirnoff brand began with a vodka distillery founded in Moscow by Pyotr Arsenievich Smirnov (1831–1898). It is distributed in 130 countries, and manufactured locally in some, as in Illinois in the United States.

Smirnoff products include vodka, flavoured vodka, and malt beverages. In 2014, Smirnoff was the best selling vodka around the world.

The vodka is unaged, made using a traditional filtration method developed by P. A. Smirnov. Recipe No. 21 was created by Smirnov's son Vladimir after escaping Russia during the October Revolution.

History
Pyotr Arsenyevitch Smirnov (9 January 1831 – 29 November 1898) founded his vodka distillery in Moscow under the trade name PA Smirnov in 1864, pioneered charcoal filtration in the 1870s, and by 1886 had captured two-thirds of the market in Moscow by virtue of the first use of newspaper advertising while suppressing clerical calls for temperance by generously contributing to the clergy. Russian royalty reportedly regarded Smirnov as a favorite. When Pyotr died, his third son Vladimir succeeded him. The company flourished and produced more than four million cases of vodka per year.

When the Tsar nationalized the Russian vodka industry in 1904, Vladimir Smirnov was forced to sell his factory and the brand. During the October Revolution of 1917, the Smirnov family fled the country. In 1920, Vladimir Smirnov established a factory in Constantinople (present day Istanbul). Four years later he moved to Lwów (then in Second Polish Republic, now Lviv in Ukraine). He renamed the vodka "Smirnoff". It sold marginally well but not nearly as it had in Russia prior to 1904. Although an additional distillery was founded in Paris in 1925, sales remained far less than that produced in Russia.

In the 1930s, Vladimir met Rudolph Kunett, a Russian who had emigrated in the 1920s to New York, and had succeeded in business. The Kunett family had been a supplier of grain to Smirnov in Moscow before the Revolution. In 1933, Vladimir sold Kunett the rights to Smirnoff vodka production and sales in North America. Kunett then returned to the United States, quit his sales job, and established his first North American distillery in Bethel, Connecticut, after the end of Prohibition in 1933. However, the business in North America was not as successful as Kunett had hoped. By 1938, Kunett could not afford the sales licenses, and contacted John Martin, president of Heublein, a company that specialized in the import and export of liquors and foreign foods. Using the $14,000 that the Heublein company made from a new product that ended up saving them from bankruptcy, Martin bought the rights to Smirnoff in 1939. His board thought he was mad. Americans were traditionally whiskey drinkers unfamiliar with vodka and so sales were slow. Sales picked up considerably after Heublein advertised it as a "white whiskey" with "no taste, no smell" sealed with whiskey corks. In 1982, the R. J. Reynolds Tobacco Company acquired Heublein Inc. for $1.4 billion. Its successor, RJR Nabisco, sold the division to Grand Metropolitan in 1987. In 1985 Heublein Corporate Audit Manager Hanson J Kan had recommended to Heublein that it acquire the Grand Metropolitan IDV Smirnoff licensee and its global locations. Grand Metropolitan merged with Guinness to form Diageo in 1997.

Since the 1990s
During the 1990s, one of Pyotr Smirnov's descendants started producing Smirnov (Смирновъ) vodka in Russia, claiming to be "The Only Real Smirnov." After a number of lawsuits, Smirnoff successfully reclaimed its trademark, while in 2006 Diageo concluded a joint venture deal with the Smirnov company.

The Smirnoff company had the naming rights to the Smirnoff Music Centre, a concert amphitheater in Dallas, Texas, from 2000-08. It also sponsored the Smirnoff Underbelly, a major venue at the Edinburgh Fringe.

In the late-1990s, Smirnoff introduced a series of new products onto the UK and later the European and North American market, which quickly became popular among young people, especially within the club scene (see "Alcopops").

There are two different products by the name of Smirnoff Ice: one, sold in France and the United States, is a citrus-flavoured malt beverage (5.0% ABV) with variants in "Original", and "Triple Black". The other, sold in Europe (excluding France), Latin America, Australia and Canada, is a premixed vodka drink. It also has variants in "Original" and "Black Ice" (or in some markets, "Triple Black" or "Double Black"), ranging from 4.5% in the UK, to 7% ABV in different markets.

The Smirnoff Ice marketed in the United States contains no vodka, according to the official Smirnoff website. It is more similar to beer than to vodka, primarily because it is brewed. However outside of the US and countries who receive US manufactured vodka it does contain Smirnoff Vodka No. 21.

Smirnoff Ice Twisted was a spin-off of the American Smirnoff Ice that featured flavors such as Mandarin Orange and Green Apple. The confusion in branding between Smirnoff Twist Vodka and Smirnoff Twisted Malt Beverage resulted in the decision to drop the "Twisted" from the flavored line of Smirnoff Ice. Current Smirnoff Ice flavors include Watermelon, Wild Grape, Passionfruit, Mango, Triple Black, Pomegranate Fusion, Arctic Berry (Blueberry), Green Apple Bite, Strawberry Acai, Pineapple and Raspberry Burst. It is sold in 22 oz. (650 ml) bottles and six-packs of 12 oz. (355 ml) bottles. The next line of Smirnoff's malt beverages to be produced was "Raw Teas", similar to the brand Twisted Tea. It comes in flavors such as Lemon, Peach, Raspberry and Green Tea. This product line has been marketed most notably with the "Tea Partay" music video and website. It is sold in six-packs of 12 oz. (355 ml) bottles.

Smirnoff Source, a lightly carbonated beer-alternative, was released in May 2007. It is citrus-flavoured and made with alcohol (3.5% ABV) and spring water and is sold in 4-packs of 1-quart (947 ml) bottles.

A line of 22 flavoured vodkas (based on the No. 21 Red Label) with the "Twist" moniker appended on the end of the name have also been introduced. Flavours include Green Apple, Orange, Cranberry, Raspberry, Citrus (Lemon), Vanilla, Strawberry, Black Cherry, Watermelon, Lime, Blueberry, White Grape, Melon (Honeydew/Cantaloupe), Pomegranate, Passion Fruit, Pear, Peach, Pineapple, Mango, Coconut, and most recently Amaretto.

In 2004, Smirnoff trialled a new blend of vodka in the UK and Canada called Smirnoff Penka. Marketing and distribution were handled by The Reserve Brands of Diageo plc. Penka is no longer available in the UK.

In a 2005 New York Times blind tasting of 21 vodkas, Smirnoff won as the "hands-down favorite".

In 2010, Smirnoff introduced the Cocktail Range. Pomegranate Martini with Meyer Lemon-flavoured Liquor and pomegranate juice, Mojito with a dash of mint and Kaffir lime and Grand Cosmopolitan with cranberry juice. Tuscan Lemonade and Savannah Tea were later added. In 2014, Smirnoff introduced Smirnoff Sours vodkas, available in Fruit Punch, Watermelon, Green Apple, and Berry Lemon.

A 2013 study found that Smirnoff malt beverages were the second-most popular brand specific alcohols consumed by underage youths in the United States.

In 2016, Smirnoff introduced two new Smirnoff Ice flavors: Electric Mandarin and Electric Berry. Also in 2016, Smirnoff introduced the new Spiked line, available in Original, Screwdriver, and Hurricane Punch, as well as their Sourced line of fruit juice vodka, available in Ruby Red Grapefruit, Pineapple and Cranberry Apple.

In 2019, Smirnoff Ice partnered with luxury brand Cremsiffino.

In 2020, Diageo introduced sugar-free Smirnoff Ice, with 4.5% ABV.

Smirnoff was mistakenly targeted for boycotts during the Russian invasion of Ukraine; however, despite its Russian origin, the brand is owned by British company Diageo and for the US market is manufactured in Illinois.

Smirnoff numbers
Most Smirnoff products have an identifying number that is displayed on the label. Some of these numbers are:
 * 21: Smirnoff Red Label, 37.5% or 40% ABV (location dependent).
 * 27: Smirnoff Silver Label Vodka, 45.2% ABV.
 * 55: Smirnoff Black, 40% ABV. A small-batch vodka that is produced in copper stills.
 * 57: Smirnoff Blue Label Vodka, 45% or 50% ABV (location dependent)
 * 60: Smirnoff Vladimir, 40%. Available only in Poland.
 * 73: Smirnoff Black Ice Triple Filtered, 7.0% ABV.

The basic Smirnoff vodka – number 21 – has performed well at spirit ratings competitions. It was awarded a double gold medal (the highest award) at the 2009 San Francisco World Spirits Competition.

Flavored vodkas
These are numbered Smirnoff vodkas with flavouring added.
 * 21: Smirnoff North (previously Smirnoff Norsk). This is the classic Smirnoff No. 21 Red Label vodka flavoured with Nordic berries. In the United Kingdom and some other markets, it is called Smirnoff Nordic Berries.
 * 21: Smirnoff Classic Mix. Smirnoff No. 21 vodka premixed with either lime soda or cola in a 70-cl bottle.
 * 21: Smirnoff "Expertly Mixed". Smirnoff No. 21 vodka premixed with cola or tonic water in a 250-ml can. Cola mix is 6.4% ABV, tonic is 7.5% ABV.
 * 21: Smirnoff Vodka and Cranberry Juice. Smirnoff No. 21 vodka premixed with Ocean Spray Cranberry Juice in a 250-ml can.
 * 21: Smirnoff Mule. Smirnoff No. 21 vodka premixed with ginger beer and lime, 4.8% ABV.
 * 21: Smirnoff Espresso. Coffee-flavoured Smirnoff No. 21 vodka, 37.5% ABV.
 * 21: Smirnoff Peppermint Twist, 30% ABV. Holiday release 2015
 * 21: Smirnoff Sours Green Apple. Smirnoff No. 21 Red Label vodka flavoured with green apple in a 500-ml, 750-ml, or 1 liter bottle. [2014]
 * 21: Smirnoff Sours Fruit Punch. Smirnoff No. 21 Red Label vodka flavoured with fruit punch in a 500-ml, 750-ml, or 1 liter bottle. [2014]
 * 21: Smirnoff Sours Watermelon. Smirnoff No. 21 Red Label vodka flavoured with watermelon in a 500-ml, 750-ml, or 1 liter bottle. [2014]
 * 21: Smirnoff Sours Berry Lemon. Smirnoff No. 21 Red Label vodka flavoured with berry and lemon in a 500-ml, 750-ml, or 1 liter bottle.
 * 57: Smirnoff Dark Roasted Espresso. Espresso-flavored vodka, 50% ABV.
 * 57: Smirnoff Spiced Root Beer. Root beer-flavored vodka, 50% ABV.

Malt beverages

 * 63: Smirnoff Twisted V Green Apple
 * 64: Smirnoff Ice Pomegranate malt beverage, 5.5% ABV
 * 66: Smirnoff Ice Raspberry Burst malt beverage, 5.0% ABV
 * 66: Smirnoff Twisted V Raspberry malt beverage
 * 67: Smirnoff Twisted V Mandarin Orange malt beverage
 * 68: Smirnoff Twisted V Black Cherry malt beverage
 * 69: Smirnoff Twisted V Watermelon malt beverage
 * 70: Smirnoff Ice Watermelon malt beverage
 * 71: Smirnoff Ice Triple Filtered malt beverage, 5.6% (4% in some locations) ABV.
 * 72: Smirnoff Ice, 5% ABV. In the United States, it is a malt beverage; elsewhere it is vodka-based. Labeled as "Spin" in South Africa.
 * 73: Smirnoff Black Ice, 7% ABV. In the United States it is a malt beverage; elsewhere it is vodka-based. Labelled as "Storm" in South Africa.
 * 74: Smirnoff Ice Triple Black. A lime-flavoured malt beverage sold in the United States, 4.5% alcohol.
 * 75: Smirnoff Ice Double Black. Sold in Australia, South Korea, and New Zealand. A variation with added Guarana is sold in South Africa & Nigeria. 6.5% ABV
 * 76: Smirnoff Ice. Sold in Canada. 7% ABV
 * 83: Smirnoff Ice Wild Grape malt beverage, 5% ABV
 * 84: Smirnoff Twist Arctic Berry
 * 85: Smirnoff Twisted Raspberry. Sold in Canada.
 * 92: Smirnoff Twisted Green Apple. Sold in Canada. 7% ABV
 * 97: Smirnoff Ice Triple Filtered. Sold in Germany and Portugal. 3% ABV
 * 103: Smirnoff Twisted V Arctic Berry
 * 110: Smirnoff Ice Double Black & Cola
 * 120: Smirnoff Ice Spice. Sold in Japan.

Products without numbers
Some Smirnoff products do not have a number on the label.

Flavoured vodkas

 * Smirnoff Fluffed Marshmallow. Marshmallow-flavored vodka, 30% ABV.
 * Smirnoff Iced Cake. Cake-flavored vodka, 30% ABV.
 * Smirnoff Kissed Caramel. Caramel-flavored vodka, 30% ABV.
 * Smirnoff Whipped Cream. Whipped cream-flavored vodka, 30% ABV.
 * Smirnoff Root Beer Float. Root beer float-flavored vodka, 30% ABV.
 * Smirnoff Cinna-Sugar Twist. Cinnamon sugar-flavored vodka. 30% ABV.
 * Smirnoff Wild Honey. Honey-flavored vodka. 30% ABV.
 * Smirnoff White. Premium Vodka Distilled at Sub-Zero Temperatures for a smoother taste. 41.3% ABV.
 * Smirnoff Red, White and Berry. Assorted berry flavored vodka, launched as part of the 2016 presidential election. Limited edition. 30% ABV.

Smirnoff Sourced

 * Smirnoff Sourced Ruby Red Grapefruit. Grapefruit-flavoured vodka with real juice added.
 * Smirnoff Sourced Pineapple. Pineapple-flavoured vodka with real juice added.
 * Smirnoff Sourced Cranberry Apple. Cranberry-Apple flavoured vodka with real juice added.

Smirnoff Ice cocktails

 * Smirnoff Ice Peach Bellini
 * Smirnoff Ice Screwdriver
 * Smirnoff Ice Watermelon Mimosa

Smirnov vodka
Smirnov (Смирновъ) can be seen as the Russian version of Smirnoff vodka. It is made by the Smirnov Trading House, a company that is part of a joint venture by Russia's Alfa Group and Diageo set up in February 2006. The full title of the Smirnov Trading House is The Trading House of the Heirs of P.A. Smirnov.

Smirnov's Vodkas
These are not to be confused with Smirnoff's Red-, Gold-, and Black-label vodkas.
 * Smirnov No.21 Vodka [50 cl, 70 cl or 1 liter bottle (40% ABV)] Red and White label with gold border. The vodka, like its Western cousin, is charcoal-filtered.
 * Smirnov ЗОЛОТАЯ (Zolotaya > "Golden") Vodka [61 cl bottle (40% ABV)] Brown and Tan label with gold border. The vodka passes through a second gold-alloy filter for a smoother taste.
 * Smirnov ИМПЕРИАЛЪ (Imperial > "Imperial") Vodka [61 cl bottle (40% ABV)] Black label with silver border. Comes in a cardboard gift box. The vodka is made in small batches and uses natural honey rather than sugar as an ingredient.
 * Smirnov ТИТУЛЪ (Titul > "Title") Vodka [50 cl or 70 cl bottle (40% ABV)] Crimson label with silver border and sculpted bottle. The 70 cl bottle comes in a cardboard gift box. The small-batch vodka is double-distilled in a copper alembic for a smoother finish.

title: Smirnoff


text: Talk:Lists of populated places in the United States

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


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Talk:Hazard ratio

I just read this article and it is clearly not written by an expert and would need a thourough re-write.

— Preceding unsigned comment added by 1.53.224.251 (talk) 14:48, 14 June 2016 (UTC)

 * I am writing in 2023, 7 years after the preceding comment, and it's still true.
 * Verytas (talk) 17:06, 30 September 2023 (UTC)

Someone please tell me that $$(1 - AUC(treatment)) \over (1 - AUC(control))$$ is a standard definition!! :-) Wikid

Isn't the AUC of dimension time? Then shouldn't the 1 be replaced by the time period considered? - Patrick 20:36 12 Jul 2003 (UTC)

Okay, just thinking aloud here. The curve has time on the horizontal axis and probability of survival (p) on the vertical axis. The AUC is thus a function of p*time. The hazard however is the hazard of death - 1-survival. So we're actually interested in the "area above the curve". The total available area = 1*time. ... so rather laboriously conclud Ratio of Hazard of Death = $$(time - AUC(treatment)) \over (time - AUC(control))$$ Next question: what's the time? - meaning that when some data are missing or censored, we can't really claim to have followed the whole group for the same length of time. How do we adjust for that? Also, how sensitive are hazard ratios to changing lengths of follow-up - what's the mathematical function that describes this? Thanks Patrick! :-) Wikid 21:07 12 Jul 2003 (UTC)

Patrick I have to confess I'm struggling a bit on this, and using it partly as an exercise to clarify my own thinking or bait some luminary to come along and set things straight once and for all. The expectations here are supposed to be the "null hypothesis" which says that tretament does not cause any difference between the treated group and controls. So one naturally asks, shouldn't it just be E(controls) in both lines. Answer: not if one can identify other things about the specific sample populations of controls and treated that might condition our expectations of their survival. In other words, the HR seems to be comparing what you might call age-sex-comorbidity standardised natural histories for the two groups. Wrapping this up into a tidy definition could take me some time (I'm not a biostatistician). But at least I can cite a reference this time! I might have a look in the British Medical Journal - they've had some good papers defining all these things. Wikid 13:15 16 Jul 2003 (UTC)

 * Okay, I think this corresponds with my last edit. - Patrick 13:26 16 Jul 2003 (UTC)

I can't work out exactly how E is calculated but from the textbook account the difference between E(treatment) and E(controls) may reflect nothing so much as the difference in actual numbers between the two groups. Oh & wooah there - the null hypothesis on survival is that natural history is the average survival of controls and treatment group combined. So even if the treated group do appear to do better, the null hypothesis would explain that as simple intrinsic variation in severity of disease. Anyhow I'll keep plugging on with this until I get it right or it "fixes itself". :-) Wikid 16:15 16 Jul 2003 (UTC)

example
For non-statistitions an interpretive example of how one would use a real hazard ratio would be helpful. 210.11.82.152 22:12, 21 June 2006 (UTC) Ted Cooper

 * I too would like to see an example used to clarify. I just glanced at the paper cited in the article |Hazard Ratio in Clinical Trials. Perhaps an example could be taken from this paper? I also scanned the same article for use of the expression of hazard as a limit and did not see it. Note that the denominator in the expression tends toward zero. Johnfravolda (talk) 15:38, 20 July 2010 (UTC)

Help! I clicked on this link to find out what Hazard ratio means. No luck! Need a quick answer for the lay reader (like, >100 is above average...)

Ditto the above. PLEASE could someone who calculates these things for simple, real-world stuff, give a couple of simple, real-word examples. (incl all the calculations of course). ‒ Jaymax✍ 00:08, 7 August 2011 (UTC)

Merger proposal
Rate ratios and hazard ratios are different names for the same quantity. I propose merging the rate ratio page to this one. --Gak (talk) 16:20, 18 September 2011 (UTC) No, they are not. HR can be interpreted as rate ratios, but not the other way round. Rate ratios can be calculated by dividing the number of events by person time whereas HR are calculated eg by Cox Regression. HR's ~ Relative Risk, however this is not in all cases — Preceding unsigned comment added by Epi micki (talk • contribs) 17:40, 20 September 2011 (UTC)

I think this confusion between hazard ratio and risk ratio is already apparent in the current version of this page:

a treatment increasing the number of one-year survivors in a population from one in 10,000 to one in 1,000 has a hazard ratio of 10.

This is not true. The relative risk is 10. With the help a statistical software, I found out that the HR is 4/3.

By contrast, a treatment group in which 50% of infections are resolved after one week (versus 25% in the control) yields a hazard ratio of two.

The OR here is 2.41 indeed.

If it takes ten weeks for all cases in the treatment group and half of cases in the control group to resolve, the ten-week hazard ratio remains at two

No: this is a degenerate case (survival probability is 0 for one group). --Borisba (talk) 10:38, 12 October 2017 (UTC)

New translation of a sample scientific paper's use of "HR" into lay English added to article's intro
I have added a paragraph to the lede that attempts to explain what the Hazard Ratio in a scientific paper might mean, in ordinary non-technical words. I am not a statistician (which is why I went to Wikipedia to find out what a Hazard Ratio is) and I hope that this explanation can be a start at making this article more useful to non-specialists.

I encourage specialists to correct the explanation, or simplify it, or improve it. But please, don't turn it into technical language that would make it useless to lay readers of encyclopedias.

I picked the cited sentence because I happened to be reading it and wondering what it meant. If you can find a simpler sentence to explain, or if its subject (Covid vaccination) is too controversial for this unrelated article, by all means, replace it with a better example. -- Gnuish (talk) 01:53, 14 June 2022 (UTC)

title: Talk:Hazard ratio


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Talk:Intellectual worker

The term "knowledge worker" has been used for about 30 years, since first introduced by Drucker (1974?) It is the commonly recognized term in the knowledge management literature. Although Machlup first described the knowledge sector of the US economy in 1962, he did not use the term knowledge worker. I must admit that I have never heard the terms "brain worker" or "intellectual worker" before this discussion. If there is any merging to be done, the latter terms should be added as subsets of "knowledge worker", not the other way around.Albert Simard 18:36, 20 August 2007 (UTC)

What, if any, is the anarchist party line on the dreaded non-disclosure agreement?

I would assume that most anarchists oppose such agreements.Pizza Puzzle

Note: The terms brain worker and knowledge worker are, I think, also in general use. -- Sam

What does an intellectual worker produce? Why should we feed and shelter such people? Sure, we need intellectuals, indeed everybody should do a bit of 'intellectual work' if they can, but people should do a bit of physical work as well. Too much division of labour could lead to the introduction of a class structure.

publunch]
 * As the eminent 20th-century Russian-American philosopher Ayn Rand proved, it is not man's muscle but man's mind that is the fundamental source of all wealth. Kurt Weber 21:23, 11 September 2005 (UTC)

Well, for better or for worse, over the last 400 years, science has given western civilization it's present standard of living. I, for one, prefer the present state of affairs over the middle ages. Hopefully, science will also enable us to undo some of the excesses of modern civilization.Albert Simard 17:18, 21 August 2007 (UTC)

Why is it stated outright that intellectual worker is only used by anarchists and communists? I was introduced to that term in an ethics class (well, "knowledge worker") on the topic of intellectual property, and that was totally outside the context of anarchism and communism. I'm going to edit this. MrVoluntarist 01:27, 24 August 2005 (UTC)

Merge with Knowledge worker
Moved to Talk:Knowledge worker. Ewlyahoocom 04:41, 6 September 2007 (UTC)

title: Talk:Intellectual worker


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Lockheed L-2000

The Lockheed L-2000 was Lockheed Corporation's entry in a government-funded competition to build the United States' first supersonic airliner in the 1960s. The L-2000 lost the contract to the Boeing 2707, but that competing design was ultimately canceled for political, environmental and economic reasons.

In 1961, President John F. Kennedy committed the government to subsidize 75% of the development of a commercial airliner to compete with the Anglo-French Concorde then under development. The director of the Federal Aviation Administration (FAA), Najeeb Halaby, elected to improve on the Concorde's design rather than compete head-to-head with it. The SST, which might have represented a significant advance over the Concorde, was intended to carry 250 passengers (a large number at the time, more than twice as many as Concorde), fly at Mach 2.7-3.0, and have a range of 4,000 mi (7,400 km).

The program was launched on June 5, 1963, and the FAA estimated that by 1990 there would be a market for 500 SSTs. Boeing, Lockheed, and North American officially responded. North American's design was soon rejected, but the Boeing and Lockheed designs were selected for further study.

Early design studies
Most of the major US aviation firms spent at least some time in the 1950s considering SST designs. Lockheed's first attempts date to 1958. Lockheed sought an airplane with cruise speeds of around 2,000 mph with takeoff and landing speeds that compared to large subsonic jets of the same era.

Early designs followed Lockheed's tapered straight wing, similar to the one used on the F-104 Starfighter, with a delta-shaped canard for aerodynamic trim. During wind-tunnel tests, this design demonstrated substantial shifts in the airplane's center of pressure (C/L). These would require large trim changes as the aircraft changed speed, causing trim drag.

A delta wing was substituted which alleviated a portion of the movement, but it was not deemed sufficient. Lockheed knew a variable geometry, swing-wing design could accomplish this goal, but felt it was too heavy: they preferred a fixed-wing solution. In a worst-case scenario, they were willing to design a fixed-wing aircraft using fuel for ballast.

By 1962, Lockheed arrived at a highly swept, cranked-arrow design featuring four engine pods buried in the wings and a canard. The improvement was closer to their goal, but still not optimal.

By 1963, they extended the leading edge of the wing forward to eliminate the need for the canard, and re-shaped the wing into a double-delta shape with a mild twist and camber. This, along with careful shaping of the fuselage, was able to control the shift in the center of pressure caused by the highly swept forward part of the wing developing lift supersonically. The engines were shifted from being buried in the wings to individual pods slung below the wings.

Later design studies

The new design was designated L-2000-1 and was 223 ft (70 m) long with a narrow-body 132 in (335.2 cm) wide fuselage to meet aerodynamic requirements, allowing for passenger seating of five abreast seating in coach and a four-abreast arrangement in first-class seating. A typical mixed-class seating layout would equal around 170 passengers, with high-density layouts exceeding 200 passengers.

The L-2000-1 featured a long, pointed nose that was almost flat on top and curved on the bottom, which allowed for improved supersonic performance, and could be drooped for takeoff and landing to provide adequate visibility. The wing design featured a sharp forward inboard sweep of 80°, with the remaining part of the wing's leading edge swept back 60°, with an overall area of 8,370 ft² (778 m²). The high sweep angles produced powerful vortices on the leading edge which increased lift at moderate to high angles of attack, yet still retained stable airflow over the control surfaces during a stall. These vortices also provided good directional control as well, which was somewhat deficient with the nose drooped at low speeds. The wing, while only 3% thick, provided substantial lift due to its large area, which, aided by vortex lift, allowed takeoff and landing speeds comparable to a Boeing 707. Additionally, a delta wing is a naturally rigid structure which requires little stiffening.

The plane's undercarriage was a traditional tricycle type with a twin-wheeled nose gear. Each of the two six-wheeled main gear utilized the same tires used on the Douglas DC-8, but which were filled with nitrogen and to lower pressures.

To provide an optimum entry date into service, Lockheed decided to use a beefed-up turbofan derivative of the Pratt & Whitney J58. The J58 had already successfully proven itself as a high-thrust, high-performance jet engine on the top-secret Lockheed A-12 (and subsequently on the Lockheed SR-71 Blackbird.) Since it was a turbofan, it was deemed to be quieter than a typical turbojet at low altitude and low speed, required no afterburner for takeoff, and allowed reduced power settings. The engines were placed in cylindrical pods with a wedge-shaped splitter, and a squarish intake providing the inlet system for the aircraft. The inlet was designed with the goal of requiring no moving parts, and was naturally stable. To reduce the noise from sonic booms, rather than penetrate the sound barrier at a more ideal 30,000 ft (9,144 m), they intended to penetrate it at 42,000 ft (12,802 m) instead. It would not be possible on hot days, but on normal days this would be achievable. Acceleration would continue through the sound barrier to Mach 1.15, at which point sonic booms would be audible on the ground. The plane would climb precisely to minimize sonic boom levels. After an initial level-off at around 71,500 ft (21,793 m), the plane would cruise climb upwards, ultimately reaching 76,500 ft (23,317 m). Descents would also be performed in a precise way to reduce sonic boom levels until subsonic speeds were reached.

By 1964, the US Government issued new requirements regarding the SST Program which required Lockheed to modify their design, by now called the L-2000-2. The new design had numerous modifications to the wing; one change was rounding the front of the forward delta in order to eliminate the pitch-up tendency. To increase high-speed aerodynamic efficiency, the wing's thickness was reduced to 2.3%, the leading edges were made sharper, the sweep angles were changed from 80/60° to 85/62°, and substantial twist and camber were added to the forward delta; much of the rear delta was twisted upwards to allow the elevons to remain flush at Mach 3.0. In addition, wing/body fairings were added on the underside of the fuselage where the wings are located, allowing a more normally shaped nose to be used. To retain low-speed performance, the rear delta was enlarged considerably; to increase the payload, the trailing edge featured a forward sweep of 10°, extending the inner part of the wing rearward. The new nose reduced the overall length to 214 ft (65.2 m) while retaining virtually the same internal dimensions. Wingspan was identical as before, and despite the thinner wing, the increased wing area of 9,026 ft² (838.5 m²) allowed the same takeoff performance. The airplane's overall lift-to-drag ratio increased from 7.25 to 7.94.

During the course of the L-2000-2's development, the engine previously selected by Lockheed was no longer deemed acceptable. During the time frame between the L-2000-1 and L-2000-2, Pratt and Whitney designed a new afterburning turbofan called the JTF-17A, which produced greater amounts of thrust. General Electric developed the GE4 which was an afterburning turbojet with variable guide-vanes, which was actually the less powerful of the two at sea level, but produced more power at high altitudes. Both engines required some degree of afterburner during cruise. Lockheed's design favored the JTF-17A over the GE-4, but there was the risk that GE would win the engine competition and Lockheed would win the SST contract, so they developed new engine pods that could accommodate either engine. Aerodynamic modifications allowed a shorter engine pod to be used and which utilized a new inlet design. This inlet featured minimal external cowl angles and was precisely contoured to allow a high-pressure recovery using no moving parts, and allowed maximum performance with either engine option. To allow additional airflow for noise-reduction, or to aid afterburner performance, a set of suck-in doors was added to the rear portion of the pod. To provide mid-air braking capability for rapid deceleration and rapid descents, and to assist ground braking, part of the nozzle could be employed as a thrust reverser at speeds below Mach 1.2. The pods were also repositioned on the new wing to better shield them from abrupt changes in airflow.

The additional thrust from the new engines allowed supersonic penetration to be delayed until up to 45,000 ft (13,716 m) under virtually all conditions. Since at this point the possibility of supersonic overland flight was still considered to be an option, Lockheed also considered larger, shorter-ranged versions of the L-2000-2B. All designs weighed exactly the same, with a new tail design, changes to the fuselage length, extensions to the forward delta, increased capacity, and variations in fuel capacity. The largest version featured capacity for 250 domestic passengers, while the medium version featured transatlantic capability with 220 passengers. Despite the fuselage length changes, there was no appreciable increase in the risk of the aircraft pitching upwards too far (over-rotation) on takeoff.

Design competition
By 1966, the design took on its final form as the L-2000-7A and L-2000-7B. The L-2000-7A featured a re-designed wing and fuselage lengthened to 273 ft (83 m). The longer fuselage allows for a mixed-class seating of 230 passengers. The new wing featured a proportionately larger forward delta, with greater refinement to the wing's twist and curvature. Despite having the same wingspan, the wing-area was increased to 9,424 ft² (875 m²), with a slightly reduced 84° sweepback, and an increased 65° main delta wing, with reduced forward sweep along the trailing edge. Unlike previous versions, this aircraft featured a leading-edge flap to increase lift at low speeds, and to allow a slight down-elevon deflection. The fuselage, as a result of greater length, changes to the wing design, and attempts to further reduce drag, featured a slight vertical thinning in the fuselage where the wings were, a more prominent wing/body "belly" to carry fuel and cargo, a longer nose, and a refined tail. Since the airplane was not as directionally stable as before, the plane featured a ventral fin, located on the underside of the trailing fuselage. The L-2000-7B was extended to 293 ft (89 m), utilizing a lengthened cabin and a more pronounced upward-curving tail to reduce the chance of the tail striking the runway during over-rotation. Both designs had the same maximum weight of 590,000 lb (267,600 kg), and the aerodynamic lift-to-drag ratio was increased to 8:1.

Full-scale mock-ups of the Boeing 2707-200 and L-2000-7 designs were presented to the FAA, and on December 31, 1966 the Boeing design was selected. The Lockheed design was judged simpler to produce and less risky, but its performance during takeoff and at high speed was slightly lower. Because of the JTF-17A, the L-2000-7 was also predicted to be louder as well. The Boeing design was considered more advanced, representing a greater lead over the Concorde and thus more fitting to the original design mandate. Boeing eventually changed its advanced variable-geometry wing design to a simpler delta-wing similar to Lockheed's design, but with a tail. The Boeing SST was ultimately cancelled on May 20, 1971 after the US Congress stopped federal funding for the SST program on March 24, 1971.

title: Lockheed L-2000


text:
Yb

YB or Yb may refer to:

Arts and entertainment

 * YB (band), a South Korean rock band (short for Yoon Do Hyun Band)
 * YoungBoy Never Broke Again (born 1999), American rapper
 * Young Buck (born 1981), rapper

Businesses and organizations

 * Youngstown Belt Railroad, a part of the Ohio Central Railroad System
 * Ypatingasis būrys, a Nazi killing squad primarily composed of Lithuanian volunteers
 * BSC Young Boys, a Swiss football club

Computing

 * Yottabit (Yb), a unit of information used, for example, to quantify computer memory or storage capacity
 * Yottabyte (YB), a unit of information used, for example, to quantify computer memory or storage capacity

Other uses

 * Yb, Russia
 * Yang Berhormat, Malay for The Honorable, styled before Members of Parliament
 * Ytterbium, symbol Yb, a chemical element

title: Yb


text:
Open system (systems theory)

An open system is a system that has external interactions. Such interactions can take the form of information, energy, or material transfers into or out of the system boundary, depending on the discipline which defines the concept. An open system is contrasted with the concept of an isolated system which exchanges neither energy, matter, nor information with its environment. An open system is also known as a flow system.

The concept of an open system was formalized within a framework that enabled one to interrelate the theory of the organism, thermodynamics, and evolutionary theory. This concept was expanded upon with the advent of information theory and subsequently systems theory. Today the concept has its applications in the natural and social sciences. In the natural sciences an open system is one whose border is permeable to both energy and mass. By contrast, a closed system is permeable to energy but not to matter.

The definition of an open system assumes that there are supplies of energy that cannot be depleted; in practice, this energy is supplied from some source in the surrounding environment, which can be treated as infinite for the purposes of study. One type of open system is the radiant energy system, which receives its energy from solar radiation – an energy source that can be regarded as inexhaustible for all practical purposes.

Social sciences
In the social sciences an open system is a process that exchanges material, energy, people, capital and information with its environment. French/Greek philosopher Kostas Axelos argued that seeing the "world system" as inherently open (though unified) would solve many of the problems in the social sciences, including that of praxis (the relation of knowledge to practice), so that various social scientific disciplines would work together rather than create monopolies whereby the world appears only sociological, political, historical, or psychological. Axelos argues that theorizing a closed system contributes to making it closed, and is thus a conservative approach. The Althusserian concept of overdetermination (drawing on Sigmund Freud) posits that there are always multiple causes in every event.

David Harvey uses this to argue that when systems such as capitalism enter a phase of crisis, it can happen through one of a number of elements, such as gender roles, the relation to nature/the environment, or crises in accumulation. Looking at the crisis in accumulation, Harvey argues that phenomena such as foreign direct investment, privatization of state-owned resources, and accumulation by dispossession act as necessary outlets when capital has overaccumulated too much in private hands and cannot circulate effectively in the marketplace. He cites the forcible displacement of Mexican and Indian peasants since the 1970s and the Asian and South-East Asian financial crisis of 1997-8, involving "hedge fund raising" of national currencies, as examples of this.

Structural functionalists such as Talcott Parsons and neofunctionalists such as Niklas Luhmann have incorporated system theory to describe society and its components.

The sociology of religion finds both open and closed systems within the field of religion.

Thermodynamics
See the book

title: Open system (systems theory)


text:
CX

CX or Cx may refer to:

Businesses and organizations

 * Cathay Pacific, a Hong Kong airline (IATA code CX)
 * Cemex, a Mexican building materials supply company (New York Stock Exchange symbol "CX")
 * Connex Melbourne, a former Australian train operator
 * Fuji TV, or CX, a Japanese television network

Biology and medicine

 * Circumflex artery (disambiguation), multiple arteries of the human body
 * Phosgene oxime, a chemical warfare agent

Computing

 * An interface in IP Multimedia Subsystems, using the diameter protocol, between Home Subscriber Server and Application Server
 * CX register, a general-purpose 16-bit X86 register
 * C++/CX (component extensions), a language extension for C++ compilers from Microsoft that enables C++ programmers to write programs for the Windows Runtime (WinRT)

Other uses in science and technology

 * CX (noise reduction), a noise reduction system, most notably used for the analog audio tracks of LaserDiscs
 * Cx, an abbreviation for the Building Commissioning process
 * Drag coefficient ($$c_\mathrm d\, ,$$ $$c_\mathrm x\,$$ or $$\!\ c_\mathrm w$$)

Places

 * Christmas Island ISO 3166-1 alpha-2 code
 * .cx, the top-level domain for Christmas Island

Transportation

 * Citroën CX, a French executive car
 * Honda CX series, a Japanese motorcycle range
 * Mitsubishi Concept-cX, a Japanese subcompact SUV concept
 * Mazda CX, the prefix for Mazda's crossover and SUV lineup

Other uses

 * 110 (number), in Roman numerals
 * Chron X, a digital collectible card game
 * Cross-examination debate, also known as Policy debate, a form of speech competition
 * Customer experience, the experiences a customer has with a supplier of goods or services
 * Cyclo-cross, a form of bicycle racing
 * Nikon CX format, an image sensor format
 * Ĉ, a letter in the Esperanto alphabet
 * Cx, a smiling emoticon
 * Cx, referencing popular streamer Ice Poseidon

title: CX


text:
Gaelic

Gaelic (pronounced for Irish Gaelic and  for Scottish Gaelic) is an adjective that means "pertaining to the Gaels". It may refer to:

Languages

 * Goidelic languages or Gaelic languages, a linguistic group that is one of the two branches of the Insular Celtic languages, including:
 * Primitive Irish or Archaic Irish, the oldest known form of the Goidelic (Gaëlic) languages
 * Old Irish or Old Gaelic, used c. AD 600–900
 * Middle Irish or Middle Gaelic, used c. AD 900–1200
 * Irish language (Gaeilge), including Classical Modern Irish and Early Modern Irish, c. 1200-1600)
 * Gaelic type, a typeface used in Ireland
 * Scottish Gaelic (Gàidhlig), historically sometimes called Erse in Scots and English
 * Canadian Gaelic (Gàidhlig Chanada or A' Ghàidhlig Chanadach), a dialect of Scottish Gaelic spoken in the Canadian Maritime region
 * Manx language (Gaelg or Gailck), Gaelic language with Norse elements

Culture and history

 * Gaelic Ireland, the history of the Gaelic people of Ireland
 * Gaelic literature
 * Gaelic revival, a movement in the late 19th century to encourage both the use of Irish Gaelic in Ireland and the revival of older Irish cultural practices
 * Gaelic-Norse, a people of combined Gaelic-Scandinavian culture influential in the Middle Ages
 * Traditional Gaelic music, the music of the Gaelic people

Sports

 * Gaelic Athletic Association the governing body of Gaelic games such as hurling and Gaelic football ( Éire / Ireland)
 * Gaelic games, traditional sports played in Ireland, notably Gaelic football, Gaelic handball, Hurling/Camogie, and Rounders.
 * Gaelic football, an Irish version of football
 * Gaelic handball, an Irish version of handball

Other uses

 * A Gaelic Blessing, a 1978 choral composition by John Rutter
 * Gaelic Symphony, an 1896 symphony composed by Amy Beach
 * SS Gaelic, two ships of the White Star Line
 * SS Empire Gaelic, a ferry in service 1949-60

title: Gaelic


text:
Talk:Gaelic

Untitled
This used to redirect to Talk:Goidelic languages, but since the main article doesn't redirect, I don't think the talk page should either. But if anyone wants to discuss the Gaelic/Goidelic languages (as opposed to this disambiguation page), that's the place to go. --Angr/undefined 14:53, 30 May 2005 (UTC)

Seems OK to me. I was in two minds about the redirect. Laurel Bush 09:54, 31 May 2005 (UTC)

Disambiguation
I am beginning disambiguation of this article (redirecting incoming links to better, more specific articles). If anyone else is doing the same job, please drop me a line so we can avoid constant edit conflicts :-P ~ Veledan • Talk + new 22:22, 17 August 2005 (UTC)
 * I already did a lot of that back in July, but there's still a long way to go. I'm glad of your help! --Angr/undefined 04:10, 2 September 2005 (UTC)
 * I've gone through about 200 links in total over the last 18 months. Maybe Scotland needs an MOS for use of term Gaelic..? - Bogger (talk) 09:50, 15 September 2009 (UTC)

Audio sample
I think it would be interesting to have an audio sample of a native Gaelic speaker, to see how the language sounds. I have no idea what might be said, but just to hear the intonations and inflections would be cool. ~MDD4696 03:34, 12 February 2006 (UTC)
 * Yes, but not here. This is a dismabig page. But audio samples at Irish language and Scottish Gaelic language would definitely be good! Angr/ talk 08:17, 12 February 2006 (UTC)

Why not just go to the BBC Scotland or RTE websites where you can listen to hours of it?

Ligature
Can this be spelled Gælic?Cameron Nedland 02:38, 2 November 2006 (UTC)
 * I've never seen it spelled that way. It's not from Latin, so there's no reason it would be. —Angr 08:35, 9 February 2007 (UTC)

Galic
While we're on the topic of alternate spellings, I'd like to introduce you to the much more interesting Galic. Simply don't use K's (there are a few other rules which I'll cite later) should we include this in Gaelic or does it deserve its own article? Than_s! 129.2.175.110 08:28, 9 February 2007 (UTC)
 * If this is your own idea that cannot be verified on the basis of independent, third-party sources, it doesn't belong on Wikipedia at all. —Angr 08:34, 9 February 2007 (UTC)

Gaelic & Gallego
I'm interested to know whether there is a connection between these two sets of languages, i.e. the Gaelic languages spoken in Ireland, Scotland, Wales, Ilse of Mann, and parts of North West France, and that of Galicia. Does anyone out there know of this.

Thanks tony w. —Preceding unsigned comment added by A1Wright (talk • contribs) 20:49, 27 September 2007 (UTC)
 * No, there's no connection. The Celtic languages (the Gaelic or Goidelic languages and Brythonic languages) belong to a completely different branch of Indo-European than Gallego/Galician, which is a Romance language. —Angr 04:25, 28 September 2007 (UTC)
 * yes it's been proven I tried adding it on this page and someone keeps deleting it. Gallego is another name for old Gallic which is a mix of two celtic language groups Galician was invented after Gallic and or Gallego. Do to Roman Rule 500 AD Gaels come from The Galegos people of The Gallaeci tribe.  Which Galicians are from. Drecelto (talk) 18:26, 17 February 2024 (UTC)

Actually, there is. A language called Old Irish, which is now completely extinct and no longer understood, developed into the newer Celtic languages of modern Irish (or Irish Gaelic), Manx Gaelic, Scottish Gaelic, Welsh, and Cornish. I think this should probably be mentioned in the article. Fionnlaoch (talk) 23:20, 25 June 2008 (UTC)
 * The question was whether there is any connection between the Goidelic languages (called "Gaelic") and the Galician language, which is Romance. Since this is just a disambiguation page, there's no reason to talk about Old Irish here (it has an article of its own). —Angr 16:41, 26 June 2008 (UTC)
 * Also, the names "Gaelic" (originally from British Celtic, compare Old Welsh guoidel "pirate, raider", Middle Welsh gwyddel, for which something like Proto-Celtic *weidelos "savage, woodsman, forest-dweller" can be reconstructed), "Galicia" (originally from the name of the Callaeci), "Gaul" (ultimately from Proto-Germanic *walhaz), "Gallia" and "Galatia" (from a Proto-Celtic verb *gal-ne- "to have power over" or "to be able to; to get under control") and, by the way, "Celts" (either from the Proto-Indo-European verbal root *kelH- "to tower, rise, project, protrude", or perhaps somehow connected with Proto-Germanic *haliþaz, from an earlier *kolet-; *kelt-o- might be a vṛddhi formation of some kind based on a cognate word) are all completely unconnected. It just so happens that Celtic-speaking peoples (unlike modern Galician, ancient Gallaecian was indeed a Celtic language, too) have found themselves with a lot of similar-sounding names starting with gal- and kel- attached to them, completely accidentally (although folk-etymology within Latin may have been involved in the modification of at least the name "Callaecia" to "Gallaecia"). --Florian Blaschke (talk) 18:38, 28 July 2014 (UTC)

Dialects?
It would be interesting to include how easy or difficult it is for those of different "dialects" to understand each other. i.e. - is Irish and Scots gaelic as similar as British and American English? Or perhaps a little less alike such as Spain and Mexico Spanish? Or are they so different so that one could not understand the other?

I don't know the answer to this myself, but it seems like it would be a rather good addition if anyone knows the answer. —Preceding unsigned comment added by 208.188.113.180 (talk) 09:02, 8 April 2008 (UTC)

 * Yes, but this isn't the page to discuss it. Differences between Irish and Scottish Gaelic would be a more appropriate place. My impression (not based on any hard evidence!) is that a person who can fluently read one can also read the other without too much difficulty, but the spoken languages are more difficult. —Angr If you've written a quality article... 15:58, 8 April 2008 (UTC)

Gàidhlig?
The article says that "in Scotland, Gaelic is often referred to by its own spelling, Gàidhlig". Assuming we're talking about people writing in English, I would dispute this: I've recently spent some time in the Western Highlands, and I have never once seen "Gàidhlig" used except in Gaelic-language texts. In English-language books, newspapers, signs (ranging from road-signs to hand-written sheets) etc it's been "Gaelic" on every single occasion. For all I know the "Gàidhlig" spelling may be used in specific circumstances, but it is certainly not general. Loganberry (Talk) 19:40, 20 July 2008 (UTC)

 * Just to be precise about this, Gàidhlig is how the word is spelt in Gaelic. It should be clear from the orthography both (a.) that the a bears a diacritic intending it to be a long and rather pure vowel, and (b.) that the original /d/ in Goidelic is preserved (though not, of course, any longer pronounced).
 * Nuttyskin (talk) 16:35, 27 July 2010 (UTC)

Move discussion in progress
There is a move discussion in progress on Talk:Scottish Gaelic which affects this page. Please participate on that page and not in this talk page section. Thank you. —RMCD bot 15:45, 15 August 2020 (UTC)

title: Talk:Gaelic


text:
Thermostat

A thermostat is a regulating device component which senses the temperature of a physical system and performs actions so that the system's temperature is maintained near a desired setpoint.

Thermostats are used in any device or system that heats or cools to a setpoint temperature. Examples include building heating, central heating, air conditioners, HVAC systems, water heaters, as well as kitchen equipment including ovens and refrigerators and medical and scientific incubators. In scientific literature, these devices are often broadly classified as thermostatically controlled loads (TCLs). Thermostatically controlled loads comprise roughly 50% of the overall electricity demand in the United States.

A thermostat operates as a "closed loop" control device, as it seeks to reduce the error between the desired and measured temperatures. Sometimes a thermostat combines both the sensing and control action elements of a controlled system, such as in an automotive thermostat. The word thermostat is derived from the Greek words θερμός thermos, "hot" and στατός statos, "standing, stationary".

Overview
A thermostat exerts control by switching heating or cooling devices on or off, or by regulating the flow of a heat transfer fluid as needed, to maintain the correct temperature. A thermostat can often be the main control unit for a heating or cooling system, in applications ranging from ambient air control to automotive coolant control. Thermostats are used in any device or system that heats or cools to a setpoint temperature. Examples include building heating, central heating, and air conditioners, kitchen equipment such as ovens and refrigerators, and medical and scientific incubators.

Construction and control
Thermostats use different types of sensors to measure temperatures and actuate control operations. Mechanical thermostats commonly use bimetallic strips, converting a temperature change into mechanical displacement, to actuate control of the heating or cooling sources. Electronic thermostats, instead, use a thermistor or other semiconductor sensor, processing temperature change as electronic signals, to control the heating or cooling equipment.

Conventional thermostats are example of "bang-bang controllers" as the controlled system either operates at full capacity once the setpoint is reached, or keeps completely off. Although it is the simplest program to implement, such control method requires to include some hysteresis in order to prevent excessively rapid cycling of the equipment around the setpoint. As a consequence, conventional thermostats cannot control temperatures very precisely. Instead, there are oscillations of a certain magnitude, usually 1-2 °C. Such control is in general inaccurate, inefficient and high-level mechanical wear, but for components like compressors, it still has a significant cost advantage compared with more advanced ones allowing continuously variable capacity.

Another consideration is the time delay of the controlled system. To improve the control performance of the system, thermostats can include an "anticipator", which stops heating/cooling slightly earlier than reaching the setpoint, as the system will continue to produce heat for a short while. Turning off exactly at the setpoint will cause actual temperature to exceed the desired range, known as "overshoot". Bimetallic sensors can include a physical "anticipator", which has a thin wire touched on the thermostat. When current passes the wire, a small amount of heat is generated and transferred to the bimetallic coil. Electronic thermostats have an electronic equivalent.

When higher control precision is required, a PID or MPC controller is preferred. However, they are nowadays mainly adopted for industrial purposes, for example, for semiconductor manufacturing factories or museums.

Sensor types
Early technologies included mercury thermometers with electrodes inserted directly through the glass, so that when a certain (fixed) temperature was reached the contacts would be closed by the mercury. These were accurate to within a degree of temperature.

Common sensor technologies in use today include:

These may then control the heating or cooling apparatus using:
 * Bimetallic mechanical or electrical sensors.
 * Expanding wax pellets
 * Electronic thermistors and semiconductor devices
 * Electrical thermocouples
 * Direct mechanical control
 * Electrical signals
 * Pneumatic signals

History
Possibly the earliest recorded examples of thermostatic control were built by a Dutch innovator, Cornelis Drebbel (1572–1633), about 1620 in England. He invented a mercury thermostat to regulate the temperature of a chicken incubator. This is one of the first recorded feedback-controlled devices.

Modern thermostatic control was developed in the 1830s by Andrew Ure (1778–1857), a Scottish chemist. The textile mills of the time needed a constant and steady temperature to operate optimally, so Ure designed the bimetallic thermostat, which would bend as one of the metals expanded in response to the increased temperature and cut off the energy supply.

Warren S. Johnson (1847–1911), of Wisconsin, patented a bi-metal room thermostat in 1883, and two years later sought a patent for the first multi-zone thermostatic control system. Albert Butz (1849–1905) invented the electric thermostat and patented it in 1886.

One of the first industrial uses of the thermostat was in the regulation of the temperature in poultry incubators. Charles Hearson, a British engineer, designed the first modern incubator for eggs, which was taken up for use on poultry farms in 1879.

Mechanical thermostats
This covers only devices which both sense and control using purely mechanical means.

Bimetal
Domestic water and steam based central heating systems have traditionally been controlled by bi-metallic strip thermostats, and this is dealt with later in this article. Purely mechanical control has been localised steam or hot-water radiator bi-metallic thermostats which regulated the individual flow. However, thermostatic radiator valves (TRV) are now being widely used.

Purely mechanical thermostats are used to regulate dampers in some rooftop turbine vents, reducing building heat loss in cool or cold periods.

Some automobile passenger heating systems have a thermostatically controlled valve to regulate the water flow and temperature to an adjustable level. In older vehicles the thermostat controls the application of engine vacuum to actuators that control water valves and flappers to direct the flow of air. In modern vehicles, the vacuum actuators may be operated by small solenoids under the control of a central computer.

Automotive
Perhaps the most common example of purely mechanical thermostat technology in use today is the internal combustion engine cooling system thermostat, used to maintain the engine near its optimum operating temperature by regulating the flow of coolant to an air-cooled radiator. This type of thermostat operates using a sealed chamber containing a wax pellet that melts and expands at a set temperature. The expansion of the chamber operates a rod which opens a valve when the operating temperature is exceeded. The operating temperature is determined by the composition of the wax. Once the operating temperature is reached, the thermostat progressively increases or decreases its opening in response to temperature changes, dynamically balancing the coolant recirculation flow and coolant flow to the radiator to maintain the engine temperature in the optimum range. On many automobile engines, including all Chrysler Group and General Motors products, the thermostat does not restrict flow to the heater core. The passenger side tank of the radiator is used as a bypass to the thermostat, flowing through the heater core. This prevents formation of steam pockets before the thermostat opens, and allows the heater to function before the thermostat opens. Another benefit is that there is still some flow through the radiator if the thermostat fails.

Shower and other hot water controls
A thermostatic mixing valve uses a wax pellet to control the mixing of hot and cold water. A common application is to permit operation of an electric water heater at a temperature hot enough to kill Legionella bacteria (above 60 C), while the output of the valve produces water that is cool enough to not immediately scald (49 C).

Analysis
A wax pellet driven valve can be analyzed through graphing the wax pellet's hysteresis which consists of two thermal expansion curves; extension (motion) vs. temperature increase, and contraction (motion) vs. temperature decrease. The spread between the up and down curves visually illustrate the valve's hysteresis; there is always hysteresis within wax driven valves due to the phase transition or phase change between solids and liquids. Hysteresis can be controlled with specialized blended mixes of hydrocarbons; tight hysteresis is what most desire, however some applications require broader ranges. Wax pellet driven valves are used in anti scald, freeze protection, over-temp purge, solar thermal energy or solar thermal, automotive, and aerospace applications among many others.

Gas expansion
Thermostats are sometimes used to regulate gas ovens. It consists of a gas-filled bulb connected to the control unit by a slender copper tube. The bulb is normally located at the top of the oven. The tube ends in a chamber sealed by a diaphragm. As the thermostat heats up, the gas expands applying pressure to the diaphragm which reduces the flow of gas to the burner.

Pneumatic thermostats
A pneumatic thermostat is a thermostat that controls a heating or cooling system via a series of air-filled control tubes. This "control air" system responds to the pressure changes (due to temperature) in the control tube to activate heating or cooling when required. The control air typically is maintained on "mains" at 15-18 psi (although usually operable up to 20 psi). Pneumatic thermostats typically provide output/ branch/ post-restrictor (for single-pipe operation) pressures of 3-15 psi which is piped to the end device (valve/ damper actuator/ pneumatic-electric switch, etc.).

The pneumatic thermostat was invented by Warren Johnson in 1895 soon after he invented the electric thermostat. In 2009, Harry Sim was awarded a patent for a pneumatic-to-digital interface that allows pneumatically controlled buildings to be integrated with building automation systems to provide similar benefits as direct digital control (DDC).

Bimetallic switching thermostats
Water and steam based central heating systems have traditionally had overall control by wall-mounted bi-metallic strip thermostats. These sense the air temperature using the differential expansion of two metals to actuate an on/off switch. Typically the central system would be switched on when the temperature drops below the setpoint on the thermostat, and switched off when it rises above, with a few degrees of hysteresis to prevent excessive switching. Bi-metallic sensing is now being superseded by electronic sensors. A principal use of the bi-metallic thermostat today is in individual electric convection heaters, where control is on/off, based on the local air temperature and the setpoint desired by the user. These are also used on air-conditioners, where local control is required.

Contact configuration nomenclature
This follows the same nomenclature as described in and. A thermostat is considered to be activated by thermal energy, thus “normal” refers to the state in which temperature is below the setpoint.
 * "NO" stands for "normally open". This is the same as "COR" ("close on rise"). May be used to start a fan when it is becoming hot, and to stop the fan when it has become cold enough.
 * "NC" stands for "normally closed". This is the same as "OOR" ("open on rise"). May be used to start a heater when it is becoming cold, and to stop the heater when it has become warm enough.
 * "CO" stands for "change over". This serves both as "NO" and "NC". May be used to start a fan when it is becoming hot, but also (on the opposite terminal), to start a heater when it is becoming cold.

Any leading number stands for number of contact sets, like "1NO", "1NC" for one contact set with two terminals. "1CO" will also have one contact set, even if it is a switch-over with three terminals.

Simple two wire thermostats

The illustration is the interior of a common two wire heat-only household thermostat, used to regulate a gas-fired heater via an electric gas valve. Similar mechanisms may also be used to control oil furnaces, boilers, boiler zone valves, electric attic fans, electric furnaces, electric baseboard heaters, and household appliances such as refrigerators, coffee pots and hair dryers. The power through the thermostat is provided by the heating device and may range from millivolts to 240 volts in common North American construction, and is used to control the heating system either directly (electric baseboard heaters and some electric furnaces) or indirectly (all gas, oil and forced hot water systems). Due to the variety of possible voltages and currents available at the thermostat, caution must be taken when selecting a replacement device.

 * 1) Setpoint control lever. This is moved to the right for a higher temperature. The round indicator pin in the center of the second slot shows through a numbered slot in the outer case.
 * 2) Bimetallic strip wound into a coil. The center of the coil is attached to a rotating post attached to lever (1). As the coil gets colder the moving end — carrying (4) — moves clockwise.
 * 3) Flexible wire. The left side is connected via one wire of a pair to the heater control valve.
 * 4) Moving contact attached to the bimetal coil. Thence, to the heater's controller.
 * 5) Fixed contact screw. This is adjusted by the manufacturer. It is connected electrically by a second wire of the pair to the thermocouple and the heater's electrically operated gas valve.
 * 6) Magnet. This ensures a good contact when the contact closes.  It also provides hysteresis to prevent short heating cycles, as the temperature must be raised several degrees before the contacts will open. As an alternative, some thermostats instead use a mercury switch on the end of the bimetal coil.  The weight of the mercury on the end of the coil tends to keep it there, also preventing short heating cycles.  However, this type of thermostat is banned in many countries due to its highly and permanently toxic nature if broken. When replacing these thermostats they must be regarded as chemical waste.

Not shown in the illustration is a separate bimetal thermometer on the outer case to show the actual temperature at the thermostat.

Millivolt thermostats
As illustrated in the use of the thermostat above, all of the power for the control system is provided by a thermopile which is a combination of many stacked thermocouples, heated by the pilot light. The thermopile produces sufficient electrical power to drive a low-power gas valve, which under control of one or more thermostat switches, in turn controls the input of fuel to the burner.

This type of device is generally considered obsolete as pilot lights can waste a surprising amount of gas (in the same way a dripping faucet can waste a large amount of water over an extended period), and are also no longer used on stoves, but are still to be found in many gas water heaters and gas fireplaces. Their poor efficiency is acceptable in water heaters, since most of the energy "wasted" on the pilot still represents a direct heat gain for the water tank. The Millivolt system also makes it unnecessary for a special electrical circuit to be run to the water heater or furnace; these systems are often completely self-sufficient and can run without any external electrical power supply. For tankless "on demand" water heaters, pilot ignition is preferable because it is faster than hot-surface ignition and more reliable than spark ignition.

Some programmable thermostats - those that offer simple "millivolt" or "two-wire" modes - will control these systems.

24-volt thermostats
The majority of modern heating/cooling/heat pump thermostats operate on low voltage (typically 24 volts AC) control circuits. The source of the 24 volt AC power is a control transformer installed as part of the heating/cooling equipment. The advantage of the low voltage control system is the ability to operate multiple electromechanical switching devices such as relays, contactors, and sequencers using inherently safe voltage and current levels. Built into the thermostat is a provision for enhanced temperature control using anticipation. A heat anticipator generates a small amount of additional heat to the sensing element while the heating appliance is operating. This opens the heating contacts slightly early to prevent the space temperature from greatly overshooting the thermostat setting. A mechanical heat anticipator is generally adjustable and should be set to the current flowing in the heating control circuit when the system is operating. A cooling anticipator generates a small amount of additional heat to the sensing element while the cooling appliance is not operating. This causes the contacts to energize the cooling equipment slightly early, preventing the space temperature from climbing excessively. Cooling anticipators are generally non-adjustable.

Electromechanical thermostats use resistance elements as anticipators. Most electronic thermostats use either thermistor devices or integrated logic elements for the anticipation function. In some electronic thermostats, the thermistor anticipator may be located outdoors, providing a variable anticipation depending on the outdoor temperature. Thermostat enhancements include outdoor temperature display, programmability, and system fault indication. While such 24 volt thermostats are incapable of operating a furnace when the mains power fails, most such furnaces require mains power for heated air fans (and often also hot-surface or electronic spark ignition) rendering moot the functionality of the thermostat. In other circumstances such as piloted wall and "gravity" (fanless) floor and central heaters the low voltage system described previously may be capable of remaining functional when electrical power is unavailable.

There are no standards for wiring color codes, but convention has settled on the following terminal codes and colors. In all cases, the manufacturer's instructions should be considered definitive.

Older, mostly deprecated designations:

Line-voltage thermostats
Line voltage thermostats are most commonly used for electric space heaters such as a baseboard heater or a direct-wired electric furnace. If a line voltage thermostat is used, system power (in the United States, 120 or 240 volts) is directly switched by the thermostat. With switching current often exceeding 40 amperes, using a low voltage thermostat on a line voltage circuit will result at least in the failure of the thermostat and possibly a fire. Line voltage thermostats are sometimes used in other applications, such as the control of fan-coil (fan powered from line voltage blowing through a coil of tubing which is either heated or cooled by a larger system) units in large systems using centralized boilers and chillers, or to control circulation pumps in hydronic heating applications.

Some programmable thermostats are available to control line-voltage systems. Baseboard heaters will especially benefit from a programmable thermostat which is capable of continuous control (as are at least some Honeywell models), effectively controlling the heater like a lamp dimmer, and gradually increasing and decreasing heating to ensure an extremely constant room temperature (continuous control rather than relying on the averaging effects of hysteresis). Systems which include a fan (electric furnaces, wall heaters, etc.) must typically use simple on/off controls.

Digital electronic thermostats

Newer digital thermostats have no moving parts to measure temperature and instead rely on thermistors or other semiconductor devices such as a resistance thermometer (resistance temperature detector). Typically one or more regular batteries must be installed to operate it, although some so-called "power stealing" digital thermostats (operated for energy harvesting) use the common 24-volt AC circuits as a power source, but will not operate on thermopile powered "millivolt" circuits used in some furnaces. Each has an LCD screen showing the current temperature, and the current setting. Most also have a clock, and time-of-day and even day-of-week settings for the temperature, used for comfort and energy conservation. Some advanced models have touch screens, or the ability to work with home automation or building automation systems.

Digital thermostats use either a relay or a semiconductor device such as triac to act as a switch to control the HVAC unit. Units with relays will operate millivolt systems, but often make an audible "click" noise when switching on or off.

HVAC systems with the ability to modulate their output can be combined with thermostats that have a built-in PID controller to achieve smoother operation. There are also modern thermostats featuring adaptive algorithms to further improve the inertia prone system behaviour. For instance, setting those up so that the temperature in the morning at 7 a.m. should be 21 °C (69.8 °F), makes sure that at that time the temperature will be 21 °C (69.8 °F), where a conventional thermostat would just start working at that time. The algorithms decide at what time the system should be activated in order to reach the desired temperature at the desired time. Other thermostat used for process/industrial control where on/off control is not suitable the PID control can also makes sure that the temperature is very stable (for instance, by reducing overshoots by fine tuning PID constants for set value (SV) or maintaining temperature in a band by deploying hysteresis control. )

Most digital thermostats in common residential use in North America and Europe are programmable thermostats, which will typically provide a 30% energy savings if left with their default programs; adjustments to these defaults may increase or reduce energy savings. The programmable thermostat article provides basic information on the operation, selection and installation of such a thermostat.

Ignition sequences in modern conventional systems

 * Gas
 * Start draft inducer fan/blower (if the furnace is relatively recent) to create a column of air flowing up the chimney
 * Heat ignitor or start spark-ignition system
 * Open gas valve to ignite main burners
 * Wait (if furnace is relatively recent) until the heat exchanger is at proper operating temperature before starting main blower fan or circulator pump

 * Oil
 * Similar to gas, except rather than opening a valve, the furnace will start an oil pump to inject oil into the burner

 * Electric
 * The blower fan or circulator pump will be started, and a large electromechanical relay or TRIAC will turn on the heating elements

 * Coal, grain or pellet
 * Generally rare today (though grains such as corn, wheat, and barley, or pellets made of wood, bark, or cardboard are increasing in popularity); similar to gas, except rather than opening a valve, the furnace will start a screw to drive coal/grain/pellets into the firebox

With non-zoned (typical residential, one thermostat for the whole house) systems, when the thermostat's R (or Rh) and W terminals are connected, the furnace will go through its start-up procedure and produce heat.

With zoned systems (some residential, many commercial systems — several thermostats controlling different "zones" in the building), the thermostat will cause small electric motors to open valves or dampers and start the furnace or boiler if it is not already running.

Most programmable thermostats will control these systems.

Combination heating/cooling regulation
Depending on what is being controlled, a forced-air air conditioning thermostat generally has an external switch for heat/off/cool, and another on/auto to turn the blower fan on constantly or only when heating and cooling are running. Four wires come to the centrally-located thermostat from the main heating/cooling unit (usually located in a closet, basement, or occasionally in the attic): One wire, usually red, supplies 24 volts AC power to the thermostat, while the other three supply control signals from the thermostat, usually white for heat, yellow for cooling, and green to turn on the blower fan. The power is supplied by a transformer, and when the thermostat makes contact between the 24 volt power and one or two of the other wires, a relay back at the heating/cooling unit activates the corresponding heat/fan/cool function of the unit(s).

A thermostat, when set to "cool", will only turn on when the ambient temperature of the surrounding room is above the set temperature. Thus, if the controlled space has a temperature normally above the desired setting when the heating/cooling system is off, it would be wise to keep the thermostat set to "cool", despite what the temperature is outside. On the other hand, if the temperature of the controlled area falls below the desired degree, then it is advisable to turn the thermostat to "heat".

Heat pump regulation
The heat pump is a refrigeration based appliance which reverses refrigerant flow between the indoor and outdoor coils. This is done by energizing a reversing valve (also known as a "4-way" or "change-over" valve). During cooling, the indoor coil is an evaporator removing heat from the indoor air and transferring it to the outdoor coil where it is rejected to the outdoor air. During heating, the outdoor coil becomes the evaporator and heat is removed from the outdoor air and transferred to the indoor air through the indoor coil. The reversing valve, controlled by the thermostat, causes the change-over from heat to cool. Residential heat pump thermostats generally have an "O" terminal to energize the reversing valve in cooling. Some residential and many commercial heat pump thermostats use a "B" terminal to energize the reversing valve in heating. The heating capacity of a heat pump decreases as outdoor temperatures fall. At some outdoor temperature (called the balance point) the ability of the refrigeration system to transfer heat into the building falls below the heating needs of the building. A typical heat pump is fitted with electric heating elements to supplement the refrigeration heat when the outdoor temperature is below this balance point. Operation of the supplemental heat is controlled by a second stage heating contact in the heat pump thermostat. During heating, the outdoor coil is operating at a temperature below the outdoor temperature and condensation on the coil may take place. This condensation may then freeze onto the coil, reducing its heat transfer capacity. Heat pumps therefore have a provision for occasional defrost of the outdoor coil. This is done by reversing the cycle to the cooling mode, shutting off the outdoor fan, and energizing the electric heating elements. The electric heat in defrost mode is needed to keep the system from blowing cold air inside the building. The elements are then used in the "reheat" function. Although the thermostat may indicate the system is in defrost and electric heat is activated, the defrost function is not controlled by the thermostat. Since the heat pump has electric heat elements for supplemental and reheats, the heat pump thermostat provides for use of the electric heat elements should the refrigeration system fail. This function is normally activated by an "E" terminal on the thermostat. When in emergency heat, the thermostat makes no attempt to operate the compressor or outdoor fan.

Thermostat location
The thermostat should not be located on an outside wall or where it could be exposed to direct sunlight at any time during the day. It should be located away from the room's cooling or heating vents or device, yet exposed to general airflow from the room(s) to be regulated. An open hallway may be most appropriate for a single zone system, where living rooms and bedrooms are operated as a single zone. If the hallway may be closed by doors from the regulated spaces then these should be left open when the system is in use. If the thermostat is too close to the source controlled then the system will tend to "short a cycle", and numerous starts and stops can be annoying and in some cases shorten equipment life. A multiple zoned system can save considerable energy by regulating individual spaces, allowing unused rooms to vary in temperature by turning off the heating and cooling.

Setback temperature
HVAC systems take a long time, usually one to several hours, to cool down or warm up the space from near outdoor conditions in summer or winter. Thus, it is a common practice to set setback temperatures when the space is not occupied (night and/or holidays). On the one hand, compared with maintaining at the original setpoint, substantial energy consumption can be saved. On the other hand, compared with turning off the system completely, it avoids room temperature drifting too much from the comfort zone, thus reducing the time of possible discomfort when the space is again occupied. New thermostats are mostly programmable and include an internal clock that allows this setback feature to be easily incorporated.

Dummy thermostats
It has been reported that many thermostats in office buildings are non-functional dummy devices, installed to give tenants' employees an illusion of control. These dummy thermostats are in effect a type of placebo button. However, these thermostats are often used to detect the temperature in the zone, even though their controls are disabled. This function is often referred to as "lockout".

title: Thermostat