Early years.

German publications of the 1950s and 1960s contained criticism of some features of nuclear power including its safety. Nuclear waste disposal was widely recognized as a major problem, with concern publicly expressed as early as 1954. In 1964, one author went so far as to state "that the dangers and costs of the necessary final disposal of nuclear waste could possibly make it necessary to forego the development of nuclear energy".  In the early 1960s there was a proposal to build a nuclear power station in West Berlin, but the project was dropped in 1962. Another attempt to site a reactor in a major city was made in 1967, when BASF planned to build a nuclear power station on its ground at Ludwigshafen, to supply process steam. Eventually the project was withdrawn by BASF.  The tiny hamlet of Wyhl, located just outside the Kaiserstuhl wine-growing area in the southwestern corner of Germany, was first mentioned in 1971 as a possible site for a nuclear power station. In the years that followed, local opposition steadily mounted, but this had little impact on politicians and planners. Official permission for the plant was granted and earthworks began on 17 February 1975. On 18 February, local people spontaneously occupied the site and police removed them forcibly two days later. Television coverage of police dragging away farmers and their wives through the mud helped to turn nuclear power into a major national issue. The rough treatment was widely condemned and made the wine-growers, clergy, and others all the more determined. Some local police refused to take part in the action.  Subsequent support came from the nearby university town of Freiburg. On 23 February about 30,000 people re-occupied the Wyhl site and plans to remove them were abandoned by the state government in view of the large number involved and potential for more adverse publicity. On 21 March 1975, an administrative court withdrew the construction licence for the plant. The plant was never built and the land eventually became a nature reserve.  The Wyhl occupation generated extensive national debate. This initially centred on the state government's handling of the affair and associated police behaviour, but interest in nuclear issues was also stimulated. The Wyhl experience encouraged the formation of citizen action groups near other planned nuclear sites. Many other anti-nuclear groups formed elsewhere, in support of these local struggles, and some existing citizens' action groups widened their aims to include the nuclear issue. This is how the German anti-nuclear movement evolved. Anti-nuclear success at Wyhl also inspired nuclear opposition in the rest of Europe and North America.

Other protests.

In 1976 and 1977, mass demonstrations took place at Kalkar, the site of Germany's first fast breeder reactor, and at Brokdorf, north of Hamburg. Some of these demonstrations, which always started peacefully, were organized by the World Union for Protection of Life. The circumstances at Brokdorf were similar to those at Wyhl, in that the behaviour of the police was again crucial:  The authorities had rushed through the licensing process, and police occupied the site hours before the first construction license was granted, in order to prevent a repetition of Wyhl. Demonstrators trying to enter the site a few days later got harsh treatment, and all this helped consolidate the population in opposition. In February 1977 the Minister-President of Lower Saxony, Ernst Albrecht of the Christian Democratic Union, announced that the salt mines in Gorleben would be utilised to store radioactive waste. New protests by the local population and opponents of nuclear power broke out and approximately 20,000 people attended the first large demonstration in Gorleben on 12 March 1977. Protests about Gorleben continued for several years and, in 1979, the prime minister declared that plans for a nuclear waste plant in Gorleben were “impossible to enforce for political reasons".  In 1980 an Enquete Commission of the Bundestag proposed "a paradigmatic change in energy policy away from nuclear power". This contributed to a broad shift in German public opinion, the formation of the Green Party, and its election to the German Bundestag in 1983.  In the early 1980s plans to build a nuclear fuel reprocessing plant in the Bavarian town of Wackersdorf lead to major protests. In 1986, West German police were confronted by demonstrators armed with slingshots, crowbars and Molotov cocktails at the site of a nuclear reprocessing plant in Wackersdorf. The plans for the plant were abandoned in 1988. It still isn't clear whether protests or plant economics led to the decision.  In 1981, Germany's largest anti-nuclear demonstration took place to protest against the construction of the Brokdorf Nuclear Power Plant on the North Sea coast west of Hamburg. Some 100,000 people came face to face with 10,000 police officers. Twenty-one policemen were injured by demonstrators armed with gasoline bombs, sticks, stones and high-powered slingshots. The plant began operations in October 1986 and is scheduled to close in 2018.

Chernobyl disaster.

The Chernobyl disaster in 1986 was a pivotal event for Germany's anti-nuclear movement. After the radioactive fallout cloud covered large parts of the country, Germans went to great lengths to deal with the contamination. Contaminated crops were destroyed, firemen dressed in protective gear cleaned cars as they crossed the border from other countries, and sand in playground sandboxes was replaced.  Following Chernobyl, the Green Party strived "for the immediate shut-down of all nuclear facilities". The SPD pushed for a nuclear phase-out within ten years. Länder governments, municipalities, parties and trade unions explored the question of "whether the use of nuclear power technology was reasonable and sensible for the future".  In May 1986 clashes between anti-nuclear protesters and West German police became common. More than 400 people were injured in mid-May at the site of a nuclear-waste reprocessing plant being built near Wackersdorf. Police "used water cannons and dropped tear-gas grenades from helicopters to subdue protesters armed with slingshots, crowbars and Molotov cocktails".

More recent developments.

Several advanced reactor designs in Germany were unsuccessful. Two fast breeder reactors were built, but both were closed in 1991 without the larger ever having achieved criticality. The High Temperature Reactor THTR-300 at Hamm-Uentrop, under construction since 1970, was started in 1983, but was shut down in September 1989.  The anti-nuclear protests were also a driving force of the green movement in Germany, from which the party The Greens evolved. When they first came to power in the Schröder administration of 1998 they achieved their major political goal for which they had fought for 20 years: abandoning nuclear energy in Germany.  From the mid-1990s onwards, anti-nuclear protests were primarily directed against transports of radioactive waste called "castor" containers. In 1996 there were sit-ins against the second castor consignment bringing nuclear waste from La Hague in France to Gorleben. In 1997 the third castor transport reached Gorleben despite the efforts of several thousand protesters.  In 2002, the "Act on the structured phase-out of the utilization of nuclear energy for the commercial generation of electricity" took effect, following a drawn-out political debate and lengthy negotiations with nuclear power plant operators. The act legislated for the shut-down of all German nuclear plants by 2021. The Stade Nuclear Power Plant was the first one to go offline in November 2003, followed by the Obrigheim Nuclear Power Plant in 2005. Block-A of the Biblis Nuclear Power Plant is still provisionally scheduled to be shut down in 2008. Block-B is going back online after a year-long shutdown on 13 or 14 December 2007 and is scheduled to keep operating until 2009 or 2012.  In 2007, amid concerns that Russian energy supplies to western Europe may not be reliable, conservative politicians, including Chancellor Angela Merkel and Economics Minister Michael Glos, continued to question the decision to phase out nuclear power in Germany. WISE along with other anti-nuclear movement groups contend that the climate problem can only be solved by the use of renewable forms of energy along with efficient and economical energy technologies.  In summer 2008, a cover of the German magazine Der Spiegel read "Atomkraft - Das unheimliche Comeback "(Nuclear Power - Its eerie comeback). As a consequence the Germans anti-nuclear organisation "" decided to coordinate the various anti-nuclear movements on their website leading to a more powerful protest. Anti-nuclear Monday evening walks become popular in various German cities.  In November 2008, a shipment of radioactive waste from German nuclear plants arrived at a storage site near Gorleben after being delayed by large protests from nuclear activists. More than 15,000 people took part in the protests which involved blocking trucks with sit-down demonstrations and blocking the route with tractors. The demonstrations were partly a response to conservative calls for a rethink of the planned phaseout of nuclear power stations.  In April 2009, activists blocked the entrance to controversial Neckarwestheim Nuclear Power Plant with an 8-metre wall. Their protest coincided with the annual meeting of the company that runs the plant, EnBW Energie Baden-Württemberg.  Also in April 2009 about 1,000 people demonstrated against nuclear power generation in the north-western city of Münster. Located southwest of Hamburg, Münster is surrounded by a nuclear waste dump at Ahaus, Germany's only uranium enrichment plant at Gronau and another such plant at Almelo in neighbouring Holland.  On 24 April 2010, about 120,000 people built a human chain ("KETTENreAKTION!") between the nuclear plants Krümmel and Brunsbüttel. This way they were demonstrating against the plans of the German government to extend the period of producing nuclear power. Demonstrations were also held in other German cities "where public opinion is mainly opposed to nuclear energy".  In September 2010, German government policy shifted back toward nuclear energy, and this generated some new anti-nuclear sentiment in Berlin and beyond. On 18 September 2010, tens of thousands of Germans surrounded Chancellor Angela Merkel’s office in an anti-nuclear demonstration that organisers said was the biggest of its kind since the Chernobyl disaster in 1986. In October 2010, tens of thousands of people protested in Munich against the nuclear power policy of Chancellor Angela Merkel's coalition government. Protesters called for a move away from nuclear power towards renewable energy. The action was the biggest anti-nuclear event in Bavaria for more than two decades.  In November 2010, police wielding batons clashed with protesters who disrupted the passage of a train carrying reprocessed nuclear waste from France to Germany. The train carrying the nuclear waste was heading for Dannenberg where the 123 tonnes of waste was loaded onto trucks and taken to the nearby storage facility of Gorleben, in central Germany. Tens of thousands of protesters gathered in Dannenberg to signal their opposition to the cargo. Organisers said 50,000 people had turned out but police said the figure was closer to 20,000. Around 16,000 police were mobilised to deal with the protests.

Post Fukushima.

In light of the Fukushima nuclear disaster, public opposition intensified. 60,000 Germans participated in a protest on 12 March 2011, forming a 45-km human chain from Stuttgart to the Neckarwestheim power plant. 110,000 people protested in 450 other German towns on 14 March, with opinion polls indicating 80% of Germans opposed the government's extension of nuclear power. On 15 March 2011, Angela Merkel said that seven nuclear power plants which went online before 1980 would be temporarily closed and the time would be used to study speedier renewable energy commercialization. Merkel has effectively reversed a previous decision to keep older nuclear plants operating beyond their previously designated life span.  Former proponents of nuclear energy such as Angela Merkel, Guido Westerwelle, Stefan Mappus have changed their positions, yet 71% of the population believe that to be a tactical maneuvre related to upcoming state elections. In the largest anti-nuclear demonstration ever held in Germany, some 250,000 people protested on 26 March under the slogan "Fukushima reminds - shut off all nuclear plants." The 27 March state elections in Baden-Württemberg and Rhineland-Palatinate saw the Greens gain their voting share significantly as a result of their long-time anti-nuclear politics, ending up with the second largest share of the vote in the Baden-Württemberg election.  In March 2011, more than 200,000 people took part in anti-nuclear protests in four large German cities, on the eve of state elections. Organisers called it the biggest anti-nuclear demonstration the country has seen, with police estimating that 100,000 people turned out in Berlin alone. Hamburg, Munich and Cologne also saw big demonstrations. The "New York Times" reported that "most Germans have a deep-seated aversion to nuclear power, and the damage at the Fukushima Daiichi plant in Japan has galvanized opposition". Thousands of Germans demanding an end to the use of nuclear power took part in nationwide demonstrations on 2 April 2011. About 7,000 people took part in anti-nuclear protests in Bremen. About 3,000 people protested outside of RWE's headquarters in Essen. Other smaller rallies were held elsewhere.  Chancellor Angela Merkel's coalition announced on 30 May 2011, that Germany's 17 nuclear power stations will be shut down by 2022, in a policy reversal following Japan's Fukushima I nuclear accidents. Seven of the German power stations were closed temporarily in March, and they will remain off-line and be permanently decommissioned. An eighth was already off line, and will stay so. Between 2011 and 2014 Germany burned more coal, an additional 9.5 million tonnes of oil equivalent.  In November 2011, thousands of anti-nuclear protesters delayed a train carrying radioactive waste from France to Germany. Many clashes and obstructions made the journey the slowest one since the annual shipments of radioactive waste began in 1995. The shipment, the first since Japan's Fukishima nuclear disaster, faced large protests in France where activists damaged the train tracks. Thousands of people in Germany also interrupted the train's journey, forcing it to proceed at a snail's pace, covering 1,200 kilometers (746 miles) in 109 hours. More than 200 people were reported injured in the protests and several arrests were made. Galvanised by the Fukushima nuclear disaster, first anniversary anti-nuclear demonstrations were held in Germany in March 2012. Organisers say more than 50,000 people in six regions took part.

Timeline.

Spiegel Online has presented this timeline of events associated with the anti-nuclear power movement in Germany:

The anti-nuclear movement in Germany has a long history dating back to the early 1970s when large demonstrations prevented the construction of a nuclear plant at Wyhl. The Wyhl protests were an example of a local community challenging the nuclear industry through a strategy of direct action and civil disobedience. Police were accused of using unnecessarily violent means. Anti-nuclear success at Wyhl inspired nuclear opposition throughout Germany, in other parts of Europe, and in North America. A few years later protests raised against the NATO Double-Track Decision in Germany and were followed by the foundation of the Green party.

Die Anti-Atomkraft-Bewegung in Deutschland ist eine in den 1970er Jahren entstandene soziale Bewegung, die sich gegen die zivile Nutzung der Kernenergie wendet. Im europäischen Vergleich zeichnet sich die deutsche Anti-Atomkraft-Bewegung durch ihre Stärke und insbesondere durch ihre Kontinuität aus. Joachim Radkau sieht in der deutschen Anti-Atomkraftbewegung aufgrund ihrer Beharrlichkeit den „größten und gedankenreichsten öffentlichen Diskurs der Bundesrepublik“.


Quantum mechanics.

The rules of quantum mechanics are highly successful in describing microscopic objects, atoms and elementary particles. But "macroscopic systems," like springs and capacitors, are accurately described by classical theories like classical mechanics and classical electrodynamics. If quantum mechanics were to be applicable to macroscopic objects, there must be some limit in which quantum mechanics reduces to classical mechanics. "Bohr's correspondence principle demands that classical physics and quantum physics give the same answer when the systems become large". Arnold Sommerfeld referred to the principle as "Bohrs Zauberstab" (Bohr's magic wand) in 1921.  The conditions under which quantum and classical physics agree are referred to as the correspondence limit, or the classical limit. Bohr provided a rough prescription for the correspondence limit: it occurs "when the quantum numbers describing the system are large". A more elaborated analysis of quantum-classical correspondence (QCC) in wavepacket spreading leads to the distinction between robust "restricted QCC" and fragile "detailed QCC". "Restricted QCC" refers to the first two moments of the probability distribution and is true even when the wave packets diffract, while "detailed QCC" requires smooth potentials which vary over scales much larger than the wavelength, which is what Bohr considered.  The post-1925 new quantum theory came in two different formulations. In matrix mechanics, the correspondence principle was built in and was used to construct the theory. In the Schrödinger approach classical behavior is not clear because the waves spread out as they move. Once the Schrödinger equation was given a probabilistic interpretation, Ehrenfest showed that Newton's laws hold on average: the quantum statistical expectation value of the position and momentum obey Newton's laws.  The correspondence principle is one of the tools available to physicists for selecting quantum theories corresponding to reality. The principles of quantum mechanics are broad: states of a physical system form a complex vector space and physical observables are identified with Hermitian operators that act on this Hilbert space. The correspondence principle limits the choices to those that reproduce classical mechanics in the correspondence limit.  Because quantum mechanics only reproduces classical mechanics in a statistical interpretation, and because the statistical interpretation only gives the probabilities of different classical outcomes, Bohr argued that quantum physics does not reduce to classical mechanics similarly as classical mechanics emerges as an approximation of special relativity at small velocities. He argued that classical physics exists independently of quantum theory and cannot be derived from it. His position was that it is inappropriate to understand the experiences of observers using purely quantum mechanical notions such as wavefunctions because the different states of experience of an observer are defined classically, and do not have a quantum mechanical analog. The relative state interpretation of quantum mechanics is an attempt to understand the experience of observers using only quantum mechanical notions. Niels Bohr was an early opponent of such interpretations.  Many of these conceptual problems, however, resolve in the phase-space formulation of quantum mechanics, where the "same variables with the same interpretation" are utilized to describe both quantum and classical mechanics.

Other scientific theories.

The term "correspondence principle" is used in a more general sense to mean the reduction of a new scientific theory to an earlier scientific theory in appropriate circumstances. This requires that the new theory explain all the phenomena under circumstances for which the preceding theory was known to be valid, the "correspondence limit".  For example,  In order for there to be a correspondence, the earlier theory has to have a domain of validity—it must work under "some" conditions. Not all theories have a domain of validity. For example, there is no limit where Newton's mechanics reduces to Aristotle's mechanics because Aristotle's mechanics, although academically dominant for 18 centuries, does not have any domain of validity (on the other hand, it can sensibly be said that the falling of objects through the air ("natural motion") constitutes a domain of validity for "a part of" Aristotle's mechanics).

Examples.

Bohr model.

If an electron in an atom is moving on an orbit with period, classically the electromagnetic radiation will repeat itself every orbital period. If the coupling to the electromagnetic field is weak, so that the orbit does not decay very much in one cycle, the radiation will be emitted in a pattern which repeats every period, so that the Fourier transform will have frequencies which are only multiples of. This is the classical radiation law: the frequencies emitted are integer multiples of.  In quantum mechanics, this emission must be in quanta of light, of frequencies consisting of integer multiples of, so that classical mechanics is an approximate description at large quantum numbers. This means that the energy level corresponding to a classical orbit of period must have nearby energy levels which differ in energy by, and they should be equally spaced near that level,  Bohr worried whether the energy spacing 1/ should be best calculated with the period of the energy state formula_2, or formula_3, or some average—in hindsight, this model is only the leading semiclassical approximation.  Bohr considered circular orbits. Classically, these orbits must decay to smaller circles when photons are emitted. The level spacing between circular orbits can be calculated with the correspondence formula. For a Hydrogen atom, the classical orbits have a period determined by Kepler's third law to scale as. The energy scales as, so the level spacing formula amounts to It is possible to determine the energy levels by recursively stepping down orbit by orbit, but there is a shortcut.  The angular momentum of the circular orbit scales as. The energy in terms of the angular momentum is then  Assuming, with Bohr, that quantized values of are equally spaced, the spacing between neighboring energies is This is as desired for equally spaced angular momenta. If one kept track of the constants, the spacing would be, so the angular momentum should be an integer multiple of,  This is how Bohr arrived at his model. Since only the level "spacing" is determined heuristically by the correspondence principle, one could always add a small fixed offset to the quantum number— could just as well have been.  Bohr used his physical intuition to decide which quantities were best to quantize. It is a testimony to his skill that he was able to get so much from what is only the leading order approximation. A less heuristic treatment accounts for needed offsets in the ground state L, cf. Wigner–Weyl transform.

One-dimensional potential.

Bohr's correspondence condition can be solved for the level energies in a general one-dimensional potential. Define a quantity which is a function only of the energy, and has the property that  This is the analogue of the angular momentum in the case of the circular orbits. The orbits selected by the correspondence principle are the ones that obey for integer, since  This quantity is canonically conjugate to a variable which, by the Hamilton equations of motion changes with time as the gradient of energy with. Since this is equal to the inverse period at all times, the variable increases steadily from 0 to 1 over one period.  The angle variable comes back to itself after 1 unit of increase, so the geometry of phase space in coordinates is that of a half-cylinder, capped off at = 0, which is the motionless orbit at the lowest value of the energy. These coordinates are just as canonical as, but the orbits are now lines of constant instead of nested ovoids in space.  The area enclosed by an orbit is invariant under canonical transformations, so it is the same in space as in. But in the coordinates, this area is the area of a cylinder of unit circumference between 0 and, or just. So is equal to the area enclosed by the orbit in coordinates too,  The quantization rule is that the action variable is an integer multiple of.

Multiperiodic motion: Bohr–Sommerfeld quantization.

Bohr's correspondence principle provided a way to find the semiclassical quantization rule for a one degree of freedom system. It was an argument for the old quantum condition mostly independent from the one developed by Wien and Einstein, which focused on adiabatic invariance. But both pointed to the same quantity, the action.  Bohr was reluctant to generalize the rule to systems with many degrees of freedom. This step was taken by Sommerfeld, who proposed the general quantization rule for an integrable system,  Each action variable is a separate integer, a separate quantum number.  This condition reproduces the circular orbit condition for two dimensional motion: let be polar coordinates for a central potential. Then is already an angle variable, and the canonical momentum conjugate is, the angular momentum. So the quantum condition for reproduces Bohr's rule:  This allowed Sommerfeld to generalize Bohr's theory of circular orbits to elliptical orbits, showing that the energy levels are the same. He also found some general properties of quantum angular momentum which seemed paradoxical at the time. One of these results was that the z-component of the angular momentum, the classical inclination of an orbit relative to the z-axis, could only take on discrete values, a result which seemed to contradict rotational invariance. This was called "space quantization" for a while, but this term fell out of favor with the new quantum mechanics since no quantization of space is involved.  In modern quantum mechanics, the principle of superposition makes it clear that rotational invariance is not lost. It is possible to rotate objects with discrete orientations to produce superpositions of other discrete orientations, and this resolves the intuitive paradoxes of the Sommerfeld model.

The quantum harmonic oscillator.

Here is a demonstration of how large quantum numbers can give rise to classical (continuous) behavior.  Consider the one-dimensional quantum harmonic oscillator. Quantum mechanics tells us that the total (kinetic and potential) energy of the oscillator,, has a set of discrete values, where is the angular frequency of the oscillator.  However, in a classical harmonic oscillator such as a lead ball attached to the end of a spring, we do not perceive any discreteness. Instead, the energy of such a macroscopic system appears to vary over a continuum of values. We can verify that our idea of macroscopic systems falls within the correspondence limit. The energy of the classical harmonic oscillator with amplitude, is  Thus, the quantum number has the value  If we apply typical "human-scale" values = 1kg, = 1 rad/s, and = 1 m, then ≈ 4.74×10. This is a very large number, so the system is indeed in the correspondence limit.  It is simple to see why we perceive a continuum of energy in this limit. With = 1 rad/s, the difference between each energy level is ≈ 1.05 × 10J, well below what we normally resolve for macroscopic systems. One then describes this system through an emergent classical limit.

Relativistic kinetic energy.

Here we show that the expression of kinetic energy from special relativity becomes arbitrarily close to the classical expression, for speeds that are much slower than the speed of light,.  Albert Einstein's mass-energy equation where the velocity, is the velocity of the body relative to the observer, formula_17 is the "rest" mass (the observed mass of the body at zero velocity relative to the observer), and is the speed of light.  When the velocity vanishes, the energy expressed above is not zero, and represents the "rest" energy,  When the body is in motion relative to the observer, the total energy exceeds the rest energy by an amount that is, by definition, the "kinetic" energy,  Using the approximation we get, when speeds are much slower than that of light, or,  which is the Newtonian expression for kinetic energy.

In physics, the correspondence principle states that the behavior of systems described by the theory of quantum mechanics (or by the old quantum theory) reproduces classical physics in the limit of large quantum numbers. In other words, it says that for large orbits and for large energies, quantum calculations must agree with classical calculations.

Mit Korrespondenzprinzip wurde ursprünglich eine Beziehung zwischen Termini der klassischen Physik und der Quantenmechanik bezeichnet. Der Ausdruck wurde 1920 von Niels Bohr im Kontext der älteren Quantentheorie geprägt. Es wird in diesem Zusammenhang auch als Bohrsches Korrespondenzprinzip bezeichnet.


Plot.

Cher Horowitz lives in a Beverly Hills mansion with her father Mel, a $500-an-hour litigator; her mother died during a routine liposuction procedure when Cher was a baby. Cher is attractive, popular, and wealthy. She attends Bronson Alcott High School with her best friend, Dionne Davenport, who is also wealthy and beautiful. Dionne has a long-term relationship with popular student Murray; Cher claims that this is a pointless endeavor for Dionne.  Josh, Cher's socially conscious ex-stepbrother, visits her during a break from college. They spar continually but playfully. She mocks his idealism, while he teases her for being selfish, vain and superficial, saying that her only direction in life is "toward the mall". Later Cher plays matchmaker for two hard-grading teachers at her school, Mr. Hall and Miss Geist. She facilitates the relationship between the teachers to make them relax their grading standards so she can renegotiate a bad grade on her report card. After Cher sees their newfound happiness, she realizes she enjoys doing good deeds. Cher then decides to give back to the community by "adopting" a "tragically unhip" new girl at school, Tai Frasier. Cher and Dionne give Tai a makeover, which gives Tai confidence and a sense of style.  Cher also tries to extinguish the attraction between Tai and Travis Birkenstock, an amiable skateboarding slacker, and to steer her towards Elton, a popular and wealthy student. Elton rejects Tai and fails to seduce Cher. A handsome new student at their school named Christian becomes Cher's target boyfriend; she invites him over to watch a movie at her place and tries to get closer to him, but he rejects her advances. Murray explains to Cher and Dionne that Christian is gay. Despite the failure of this endeavor, Cher remains friends with Christian, primarily due to her admiration of his taste in art and fashion.  Matters take a turn for the worse when Tai's newfound popularity strains her relationship with Cher. Cher's frustration escalates when she fails her driving test and cannot change the result. When she returns home, crushed, Tai confesses her feelings for Josh and wants Cher's help in pursuing him. Cher says Tai is not right for Josh and they quarrel. Their disagreement ends with Tai calling Cher a "virgin who can't drive". Feeling "totally clueless", Cher reflects on her priorities and her repeated failures to understand or appreciate the people in her life.  After thinking about why she is bothered by Tai's interest in Josh, Cher realizes that she loves him. She begins making awkward but sincere efforts to live a more purposeful life, including captaining the school's Pismo Beach disaster relief effort. Cher and Josh eventually admit their feelings for one another, culminating in a tender kiss. Ultimately, Mr. Hall and Miss Geist wed; Cher's friendships with Tai and Dionne are solidified; Tai and Travis are in love and Cher catches the wedding bouquet, helping Josh win a $200 bet. She embraces Josh and they kiss.

Production.

Development.

According to the special feature titled ""Creative Writing"", Heckerling describes the origins of "Clueless" as follows: She follows up on the connections to the Jane Austen novel, "Emma": Associate producer Twink Caplan recalls what the proposed TV show's initial title: Fox picked up the picture, but put the film in a turnaround. The male studio heads wanted Heckerling to rewrite the script so that fewer women would feature. Six months later, the script made its way to producer Scott Rudin. Rudin liked the script and it was the subject of a bidding war, with Paramount Pictures beating out the other studios. Heckerling was excited, as Paramount owned several major youth-centered channels, such as MTV and Nickelodeon, which was suited to the film's target demographic.

Filming.

Principal photography for the film took place between November 21 and December 31, 1994. The film had a 40-day filming schedule. Producers sat in on classes at Beverly Hills High School to get a feel for the student culture. Herb Hall, the real drama teacher at Beverly Hills High School, had a short scene as the principal in the film. Scenes depicting the high school campus, including the tennis courts, the outdoor cafeteria, the quad, and various classrooms were filmed at Occidental College in Los Angeles. The mall scenes were filmed at Westfield Fashion Square in Sherman Oaks, California.

Reception.

Box office.

The film became a surprise sleeper hit of 1995. "Clueless" opened in 1,653 theaters on July 19, 1995 and grossed $10,612,443 on its opening weekend, which led to a ranking of second behind "Apollo 13". The film grossed $56,631,572 during its theatrical run, becoming the 32nd-highest-grossing film of 1995. This box office success brought the then-largely unknown Silverstone to international attention. The film also developed a strong cult following after its release.

Critical response.

The film was well received by critics. Review aggregation website Rotten Tomatoes gives it a score of 80% based on reviews from 65 critics and judged it "Certified Fresh" with an average rating of 6.88/10. The site's critical consensus reads: "A funny and clever reshaping of "Emma", "Clueless" offers a soft satire that pokes as much fun at teen films as it does at the Beverly Hills glitterati." On Metacritic, the film has a 68 out of 100 rating based on 18 reviews, which indicates "generally positive reviews".  The film was seen as a teen flick that had a strong influence on fashion trends and lingo. Fashion as a form of self-expression played an important role in the narrative and character development of the film, television series, and novels, which are topics examined by Alice Leppert.  Roger Ebert of the "Chicago Sun-Times" gave the film three-and-a-half out of four stars. Janet Maslin of "The New York Times" notes, "Even if "Clueless" runs out of gas before it's over, most of it is as eye-catching and cheery as its star." Peter Travers of "Rolling Stone" gave the film four stars, contrasting it to the more adult-oriented film about teenagers released around the same time, "Kids", stating, "The materialism in "Clueless" is almost as scary as the hopelessness in "Kids"."

Accolades.

In 2008, "Entertainment Weekly" selected "Clueless" as one of the "New Classics," a list of 100 released between 1983 and 2008; "Clueless" was ranked 42nd, and they named it the 19th-best comedy of the past 25 years.  American Film Institute recognition:

Comparison to "Emma".

"Clueless" is a loose adaptation of Jane Austen's 1815 novel "Emma", and many of its characters have counterparts in the novel.

Home media.

"Clueless" was released on VHS and LaserDisc on December 19, 1995 by Paramount Home Video. It was released on DVD on October 19, 1999. The special features only included two theatrical trailers.  The film was reissued in a special tenth-anniversary ""Whatever!" Edition" DVD on August 30, 2005. The new issue included featurettes and cast interviews, including:"The Class of '95" (a look at the cast), "Creative Writing" (Amy Heckerling talks about the script), "Fashion 101" (how filmmakers invented the trendsetting style of "Clueless"), "Language Arts" (the director and cast members give facts on the groundbreaking slang and how "Clueless" revived Valspeak slang), "Suck and Blow" (how to play the game depicted in the Sun Valley party scene), "Driver's Ed", "We're History" (stories from cast and crew of "Clueless"), and two theatrical trailers.  It was released on Blu-ray on May 1, 2012. Special features were carried over from the ""Whatever!" Edition" of 2005 and included a new trivia track.

Cultural impact and legacy.

Cast.

After the death of Brittany Murphy, Silverstone stated that she "always felt connected to [Murphy] as [they] shared a very special experience in [their] lives together", and said "I loved working with Brittany. She was so talented, so warm, and so sweet."  Heckerling later described Silverstone as having "that Marilyn Monroe thing" as a "pretty, sweet blonde who, in spite of being the American ideal, people still really like."  The surviving cast reunited in 2012 for an issue of "Entertainment Weekly".  Heckerling later reunited with both Silverstone and Shawn for the vampire comedy "Vamps".

Popular culture and society.

The film was well known for the characters' catchphrases and vocabulary. Cher's verbal style is also marked by ironic contrasts between current slang and historical references, such as when she compares Tai to "those Botticelli chicks".  "Clueless" was the main inspiration for Australian rapper Iggy Azalea's music video for her 2014 song "Fancy" featuring Charli XCX. Many visuals and costumes inspired by the film were used in the video, which is filled with remakes of "Clueless" scenes. The outfits are also reinvented to channel the famous stylings of the film with a slightly modern edge. "Fancy" was shot in the same Los Angeles high school where "Clueless" was filmed.  In the second episode of the second season of the BBC America thriller series "Killing Eve", "Nice and Neat" (2019), the Russian assassin Villanelle calls her agency and uses the codename Cher Horowitz to secretly inform her boss that she is in trouble and needs to be rescued after being kidnapped.  In a 2020 Discover Card commercial, a clip from the film was featured which consisted of Cher Horowitz saying her famous phrase "Uh uh, no way".

Spin-offs and adaptations.

Television.

In 1996, the producers created a spin-off television series, which followed the continuing adventures of Cher and her friends. Several cast members from the film went on to star in the series, with the notable exceptions of Silverstone (who went on to sign a film deal with Columbia-TriStar worth $10 million) and Rudd (whose film career began to take off). Silverstone was replaced in the series with actress Rachel Blanchard.  In October 2019, it was announced that CBS would be adapting the film into a drama series. The series will be centered around Dionne after Cher goes missing, and is described by "Deadline" as a "baby pink and bisexual blue-tinted, tiny sunglasses-wearing, oat milk latte and Adderall-fueled look at what happens when the high school queen bee Cher disappears and her lifelong number two Dionne steps into Cher's vacant Air Jordans."

Books.

Simon Spotlight Entertainment spun off a collection of paperback books, from 1995 to 1999, aimed at adolescent readers.  In 2015, to celebrate the film's twentieth anniversary, pop culture writer Jen Chaney published a book titled "As If!: The Oral History of Clueless". The book is based on exclusive interviews with Amy Heckerling, Alicia Silverstone, and other cast and crew members. Excerpts from the book were published in "Vanity Fair".

Comics.

A comic book series was launched in 2017.

Stage musical.

"Clueless: The Musical" opened in New York City on December 11, 2018, as part of The New Group's 2018–2019 season. The show was written by Heckerling and starred Dove Cameron as Cher and Dave Thomas Brown as Josh. It closed on January 12, 2019.  The musical was a jukebox musical featuring pop songs from the 1990s, though with lyrics mostly or entirely rewritten by Heckerling to fit the storyline. Songs adapted from the movie's soundtrack included "Supermodel" and "Kids in America."

Web story.

In 2017, Episode launched an animated web story based on the film.

Clueless is a 1995 American coming-of-age teen comedy film written and directed by Amy Heckerling. It stars Alicia Silverstone, Stacey Dash, Paul Rudd, Dan Hedaya, and Brittany Murphy. It was produced by Scott Rudin and Robert Lawrence. It is loosely based on Jane Austen's 1815 novel "Emma", with a modern-day setting of Beverly Hills. The plot centers on Cher Horowitz, a beautiful, clever and rich high school student who befriends a new student named Tai Frasier and decides to give her a makeover.

Clueless – Was sonst! (Originaltitel: "Clueless") ist eine Teenager-Komödie aus dem Jahr 1995 von Regisseurin Amy Heckerling, die auch das Drehbuch schrieb. Die Hauptrolle spielte Alicia Silverstone. Der Film ist eine modernisierte Variante von Jane Austens Roman "Emma".


History and procurement.

The SIM card is a type of smart card, the basis for which is the silicon integrated circuit (IC) chip. The idea of incorporating a silicon IC chip onto a plastic card originates from the late 1960s. Smart cards have since used MOS integrated circuit chips, along with MOS memory technologies such as flash memory and EEPROM (electrically erasable programmable read-only memory).  The SIM was initially specified by the European Telecommunications Standards Institute in the specification with the number TS 11.11. This specification describes the physical and logical behaviour of the SIM. With the development of UMTS, the specification work was partially transferred to 3GPP. 3GPP is now responsible for the further development of applications like SIM (TS 51.011) and USIM (TS 31.102) and ETSI for the further development of the physical card UICC.  The first SIM card was developed in 1991 by Munich smart-card maker Giesecke & Devrient, who sold the first 300 SIM cards to the Finnish wireless network operator Radiolinja.  Today, SIM cards are ubiquitous, allowing over 7 billion devices to connect to cellular networks around the world. According to the International Card Manufacturers Association (ICMA), there were 5.4 billion SIM cards manufactured globally in 2016 creating over $6.5 billion in revenue for traditional SIM card vendors. The rise of cellular IoT and 5G networks is predicted to drive the growth of the addressable market for SIM card manufacturers to over 20 billion cellular devices by 2020. The introduction of Embedded SIM (eSIM) and remote SIM provisioning (RSP) from the GSMA may disrupt the traditional SIM card ecosystem with the entrance of new players specializing in "digital" SIM card provisioning and other value-added services for mobile network operators.

Design.

There are three operating voltages for SIM cards:, and (ISO/IEC 7816-3 classes A, B and C, respectively). The operating voltage of the majority of SIM cards launched before 1998 was. SIM cards produced subsequently are compatible with and. Modern cards support, and.  Modern SIM cards allow applications to load when the SIM is in use by the subscriber. These applications communicate with the handset or a server using SIM Application Toolkit, which was initially specified by 3GPP in TS 11.14. (There is an identical ETSI specification with different numbering.) ETSI and 3GPP maintain the SIM specifications. The main specifications are: ETSI TS 102 223 (the toolkit for smartcards), ETSI TS 102 241 (API), ETSI TS 102 588 (application invocation), and ETSI TS 131 111 (toolkit for more SIM-likes). SIM toolkit applications were initially written in native code using proprietary APIs. To provide interoperability of the applications, ETSI chose Java Card. A multi-company collaboration called GlobalPlatform defines some extensions on the cards, with additional APIs and features like more cryptographic security and RFID contactless use added.

Data.

SIM cards store network-specific information used to authenticate and identify subscribers on the network. The most important of these are the ICCID, IMSI, Authentication Key (Ki), Local Area Identity (LAI) and Operator-Specific Emergency Number. The SIM also stores other carrier-specific data such as the SMSC (Short Message service center) number, Service Provider Name (SPN), Service Dialing Numbers (SDN), Advice-Of-Charge parameters and Value Added Service (VAS) applications. (Refer to GSM 11.11)  SIM cards can come in various data capacities, from to at least. All can store a maximum of 250 contacts on the SIM, but while the has room for 33 Mobile Network Codes (MNCs) or "network identifiers", the version has room for 80 MNCs. This is used by network operators to store data on preferred networks, mostly used when the SIM is not in its home network but is roaming. The network operator that issued the SIM card can use this to have a phone connect to a preferred network that is more economic for the provider instead of having to pay the network operator that the phone'saw' first. This does not mean that a phone containing this SIM card can connect to a maximum of only 33 or 80 networks, but it means that the SIM card issuer can specify only up to that number of preferred networks. If a SIM is outside these preferred networks it uses the first or best available network.

ICCID.

Each SIM is internationally identified by its integrated circuit card identifier (ICCID). ICCID is the identifier of the actual SIM card itself – i.e. an identifier for the SIM chip. Nowadays ICCID numbers are also used to identify eSIM profiles, and not only physical SIM cards. ICCIDs are stored in the SIM cards and are also engraved or printed on the SIM card body during a process called personalisation. The ICCID is defined by the ITU-T recommendation E.118 as the "Primary Account Number". Its layout is based on ISO/IEC 7812. According to E.118, the number can be up to 22 digits long, including a single check digit calculated using the Luhn algorithm. However, the GSM Phase 1 defined the ICCID length as an opaque data field, 10 octets (20 digits) in length, whose structure is specific to a mobile network operator.  The number is composed of the following subparts:  Issuer identification number (IIN)  Maximum of seven digits: Individual account identification Check digit  With the GSM Phase 1 specification using 10 octets into which ICCID is stored as packed BCD, the data field has room for 20 digits with hexadecimal digit "F" being used as filler when necessary.  In practice, this means that on GSM SIM cards there are 20-digit (19+1) and 19-digit (18+1) ICCIDs in use, depending upon the issuer. However, a single issuer always uses the same size for its ICCIDs.  To confuse matters more, SIM factories seem to have varying ways of delivering electronic copies of SIM personalization datasets. Some datasets are without the ICCID checksum digit, others are with the digit.  As required by E.118, the ITU-T updates a list of all current internationally assigned IIN codes in its Operational Bulletins which are published twice a month (the last is No. 1163 from 1 January 2019). ITU-T also publishes complete lists: as of January 2019, the list issued on 1 December 2018 was current, having all issuer identifier numbers before 1 December 2018.

International mobile subscriber identity (IMSI).

SIM cards are identified on their individual operator networks by a unique International Mobile Subscriber Identity (IMSI). Mobile network operators connect mobile phone calls and communicate with their market SIM cards using their IMSIs. The format is:

Authentication key (K).

The K is a 128-bit value used in authenticating the SIMs on a GSM mobile network (for USIM network, you still need K but other parameters are also needed). Each SIM holds a unique K assigned to it by the operator during the personalization process. The K is also stored in a database (termed authentication center or AuC) on the carrier's network.  The SIM card is designed to prevent someone from getting the K by using the smart-card interface. Instead, the SIM card provides a function, "Run GSM Algorithm", that the phone uses to pass data to the SIM card to be signed with the K. This, by design, makes using the SIM card mandatory unless the K can be extracted from the SIM card, or the carrier is willing to reveal the K. In practice, the GSM cryptographic algorithm for computing SRES_2 (see step 4, below) from the K has certain vulnerabilities that can allow the extraction of the K from a SIM card and the making of a duplicate SIM card.  Authentication process:

Location area identity.

The SIM stores network state information, which is received from the Location Area Identity (LAI). Operator networks are divided into Location Areas, each having a unique LAI number. When the device changes locations, it stores the new LAI to the SIM and sends it back to the operator network with its new location. If the device is power cycled, it takes data off the SIM, and searches for the prior LAI.

SMS messages and contacts.

Most SIM cards store a number of SMS messages and phone book contacts. It stores the contacts in simple "name and number" pairs. Entries that contain multiple phone numbers and additional phone numbers are usually not stored on the SIM card. When a user tries to copy such entries to a SIM, the handset's software breaks them into multiple entries, discarding information that is not a phone number. The number of contacts and messages stored depends on the SIM; early models stored as few as five messages and 20 contacts, while modern SIM cards can usually store over 250 contacts.

Formats.

SIM cards have been made smaller over the years; functionality is independent of format. Full-size SIM were followed by mini-SIM, micro-SIM, and nano-SIM. SIM cards are also made to embed in devices.  All versions of the non-embedded SIM cards share the same ISO/IEC 7816 pin arrangement.

Full-size SIM.

The "full-size SIM" (or 1FF, 1st form factor) was the first form factor to appear. It was the size of a credit card (85.60 mm × 53.98 mm × 0.76 mm). Later smaller SIMs are often supplied embedded in a full-size card from which they can be removed.

Mini-SIM.

The "mini-SIM" (or 2FF) card has the same contact arrangement as the full-size SIM card and is normally supplied within a full-size card carrier, attached by a number of linking pieces. This arrangement (defined in ISO/IEC 7810 as ID-1/000) lets such a card be used in a device that requires a full-size card or in a device that requires a mini-SIM card, after breaking the linking pieces. As the full-size SIM is no longer used, some suppliers refer to the mini-SIM as a "standard SIM" or "regular SIM".

Micro-SIM.

The "micro-SIM" (or 3FF) card has the same thickness and contact arrangements, but reduced length and width as shown in the table above.  The micro-SIM was introduced by the European Telecommunications Standards Institute (ETSI) along with SCP, 3GPP (UTRAN/GERAN), 3GPP2 (CDMA2000), ARIB, GSM Association (GSMA SCaG and GSMNA), GlobalPlatform, Liberty Alliance, and the Open Mobile Alliance (OMA) for the purpose of fitting into devices too small for a mini-SIM card.  The form factor was mentioned in the December 1998 3GPP SMG9 UMTS Working Party, which is the standards-setting body for GSM SIM cards, and the form factor was agreed upon in late 2003.  The micro-SIM was designed for backward compatibility. The major issue for backward compatibility was the contact area of the chip. Retaining the same contact area makes the micro-SIM compatible with the prior, larger SIM readers through the use of plastic cutout surrounds. The SIM was also designed to run at the same speed (5 MHz) as the prior version. The same size and positions of pins resulted in numerous "How-to" tutorials and YouTube video with detailed instructions how to cut a mini-SIM card to micro-SIM size.  The chairman of EP SCP, Dr. Klaus Vedder, said  Micro-SIM cards were introduced by various mobile service providers for the launch of the original iPad, and later for smartphones, from April 2010. The iPhone 4 was the first smartphone to use a micro-SIM card in June 2010, followed by many others.

Nano-SIM.

The "nano-SIM" (or 4FF) card was introduced on 11 October 2012, when mobile service providers in various countries started to supply it for phones that supported the format. The nano-SIM measures and reduces the previous format to the contact area while maintaining the existing contact arrangements. A small rim of isolating material is left around the contact area to avoid short circuits with the socket. The nano-SIM is thick, compared to the of its predecessor. 4FF can be put into adapters for use with devices designed for 2FF or 3FF SIMs, and is made thinner for that purpose, and telephone companies give due warning about this.  The iPhone 5, released in September 2012, was the first device to use a nano-SIM card, followed by other handsets.

Security.

In July 2013, Karsten Nohl, a security researcher from SRLabs, described vulnerabilities in some SIM cards that supported DES, which, despite its age, is still used by some operators. The attack could lead to the phone being remotely cloned or let someone steal payment credentials from the SIM. Further details of the research were provided at BlackHat on July 31, 2013.  In response, the International Telecommunication Union said that the development was "hugely significant" and that it would be contacting its members.  In February 2015, it was reported by The Intercept that the NSA and GCHQ had stolen the encryption keys (Ki's) used by Gemalto (the manufacturer of 2 billion SIM cards annually), enabling these intelligence agencies to monitor voice and data communications without the knowledge or approval of cellular network providers or judicial oversight. Having finished its investigation, Gemalto claimed that it has “reasonable grounds” to believe that the NSA and GCHQ carried out an operation to hack its network in 2010 and 2011, but says the number of possibly stolen keys would not have been massive.

Developments.

When GSM was already in use, the specifications were further developed and enhanced with functionality such as SMS and GPRS. These development steps are referred as releases by ETSI. Within these development cycles, the SIM specification was enhanced as well: new voltage classes, formats and files were introduced.

USIM.

In GSM-only times, the SIM consisted of the hardware and the software. With the advent of UMTS this naming was split: the SIM was now an application and hence only software. The hardware part was called UICC. This split was necessary because UMTS introduced a new application, the universal subscriber identity module (USIM). The USIM brought, among other things, security improvements like the mutual authentication and longer encryption keys and an improved address book.

UICC.

"SIM cards" in developed countries today are usually UICCs containing at least a SIM application and a USIM application. This configuration is necessary because older GSM only handsets are solely compatible with the SIM application and some UMTS security enhancements rely on the USIM application.

Other variants.

On cdmaOne networks, the equivalent of the SIM card is the R-UIM and the equivalent of the SIM application is the CSIM.  A "virtual SIM" is a mobile phone number provided by a mobile network operator that does not require a SIM card to connect phone calls to a user's mobile phone.

Embedded-SIM (eSIM).

An embedded-SIM (eSIM) is a form of programmable SIM that is embedded directly into a device. The surface mount format provides the same electrical interface as the full size, 2FF and 3FF SIM cards, but is soldered to a circuit board as part of the manufacturing process. In M2M applications where there is no requirement to change the SIM card, this avoids the requirement for a connector, improving reliability and security. An eSIM can be provisioned remotely; end-users can add or remove operators without the need to physically swap a SIM from the device.

Usage in mobile phone standards.

The use of SIM cards is mandatory in GSM devices.  The satellite phone networks Iridium, Thuraya and Inmarsat's BGAN also use SIM cards. Sometimes, these SIM cards work in regular GSM phones and also allow GSM customers to roam in satellite networks by using their own SIM card in a satellite phone.  Japan's 2G PDC system (which was shut down in 2012; SoftBank Mobile has already shut down PDC from March 31, 2010) also specifies a SIM, but this has never been implemented commercially. The specification of the interface between the Mobile Equipment and the SIM is given in the RCR STD-27 annex 4. The Subscriber Identity Module Expert Group was a committee of specialists assembled by the European Telecommunications Standards Institute (ETSI) to draw up the specifications (GSM 11.11) for interfacing between smart cards and mobile telephones. In 1994, the name SIMEG was changed to SMG9.  Japan's current and next generation cellular systems are based on W-CDMA (UMTS) and CDMA2000 and all use SIM cards. However, Japanese CDMA2000-based phones are locked to the R-UIM they are associated with and thus, the cards are not interchangeable with other Japanese CDMA2000 handsets (though they may be inserted into GSM/WCDMA handsets for roaming purposes outside Japan).  CDMA-based devices originally did not use a removable card, and the service for these phones bound to a unique identifier contained in the handset itself. This is most prevalent in operators in the Americas. The first publication of the TIA-820 standard (also known as 3GPP2 C.S0023) in 2000 defined the Removable User Identity Module (R-UIM). Card-based CDMA devices are most prevalent in Asia.  The equivalent of a SIM in UMTS is called the universal integrated circuit card (UICC), which runs a USIM application. The UICC is still colloquially called a "SIM card".

SIM and carriers.

The SIM card introduced a new and significant business opportunity for MVNOs mobile virtual network operators who lease capacity from one of the network operators rather than owning or operating a cellular telecoms network, and only provide a SIM card to their customers. MVNOs first appeared in Denmark, Hong Kong, Finland and the UK. Today they exist in over 50 countries, including most of Europe, United States, Canada, Mexico, Australia and parts of Asia, and account for approximately 10% of all mobile phone subscribers around the world.  On some networks, the mobile phone is locked to its carrier SIM card, meaning that the phone only works with SIM cards from the specific carrier. This is more common in markets where mobile phones are heavily subsidised by the carriers, and the business model depends on the customer staying with the service provider for a minimum term (typically 12, 18 or 24 months). SIM cards that are issued by providers with an associated contract are called "SIM-only" deals. Common examples are the GSM networks in the United States, Canada, Australia, the UK and Poland. Many businesses offer the ability to remove the SIM lock from a phone, effectively making it possible to then use the phone on any network by inserting a different SIM card. Mostly, GSM and 3G mobile handsets can easily be unlocked and used on any suitable network with any SIM card.  In countries where the phones are not subsidised, e.g., India, Israel and Belgium, all phones are unlocked. Where the phone is not locked to its SIM card, the users can easily switch networks by simply replacing the SIM card of one network with that of another while using only one phone. This is typical, for example, among users who may want to optimise their carrier's traffic by different tariffs to different friends on different networks, or when traveling internationally.  In 2016, carriers started using the concept of automatic SIM reactivation whereby they let users reuse expired SIM cards instead of purchasing new ones when they wish to re-subscribe to that operator. This is particularly useful in countries where prepaid calls dominate and where competition drives high churn rates, as users had to return to a carrier shop to purchase a new SIM each time they wanted to churn back to an operator.

SIM-only.

Commonly sold as a product by mobile telecommunications companies, "SIM-only" refers to a type of legally binding contract between a mobile network provider and a customer. The contract itself takes the form of a credit agreement and is subject to a credit check.  Within a SIM-only contract the mobile network provider supplies their customer with just one piece of hardware, a SIM card, which includes an agreed amount of network usage in exchange for a monthly payment. Network usage within a SIM-only contract can be measured in minutes, text, data or any combination of these. The duration of a SIM-only contract varies depending on the deal selected by the customer, but in the UK they are available over 1, 3, 6, and 12-month periods.  SIM-only contracts differ from mobile phone contracts in that they do not include any hardware other than a SIM card. In terms of network usage, SIM-only is typically more cost effective than other contracts because the provider does not charge more to offset the cost of a mobile device over the contract period. Short contract length is one of the key features of SIM-only made possible by the absence of a mobile device.  SIM-only is increasing in popularity very quickly. In 2010 pay monthly based mobile phone subscriptions grew from 41 percent to 49 percent of all UK mobile phone subscriptions. According to German research company GfK, 250,000 SIM-only mobile contracts were taken up in the UK during July 2012 alone, the highest figure since GfK began keeping records.  Increasing smartphone penetration combined with financial concerns are leading customers to save money by moving onto a SIM-only when their initial contract term is over.

Multiple-SIM devices.

Dual-SIM devices have two SIM card slots for the use of two SIM cards, from one or multiple carriers. Dual-SIM mobile phones come with two slots for SIMs in various locations such as: one behind the battery and another on the side of the phone; both slots behind the battery; or on the side of the phone if the device does not have a removable battery. Multiple-SIM devices are commonplace in developing markets such as in Africa, East Asia, the Indian subcontinent and Southeast Asia, where variable billing rates, network coverage and speed make it desirable for consumers to use multiple SIMs from competing networks. Dual SIM phones are also useful to separate one's personal phone number from a business phone number, without having to carry multiple devices. Some popular devices, such as the BlackBerry KeyOne have dual-SIM variants, however dual-SIM devices were not common in the US or Europe due to lack of demand. This has changed with mainline products from Apple and Google featuring either two SIM slots or a combination of a physical SIM slot and an eSIM.

Thin SIM.

A thin SIM (or overlay SIM or SIM overlay) is a very thin device shaped like a SIM card, approximately 120 microns thick. It has contacts on its front and back. It is used by sticking it on top of a regular SIM card. It provides its own functionality while passing through the functionality of the SIM card underneath. It can be used to bypass the mobile operating network and run custom applications, particularly on non-programmable cell phones.  Its top surface is a connector which connects to the phone in place of the normal SIM. Its bottom surface is a connector which connects to the SIM in place of the phone. With electronics, it can modify signals in either direction, thus presenting a modified SIM to the phone, and/or presenting a modified phone to the SIM. It is a similar concept to the Game Genie, which connects between a game console and a game cartridge, creating a modified game.  A bank in Kenya is issuing thin SIMs to its customers, raising security concerns by competition but after months of security testing and legal hearing before a Parliamentary Committee on Energy, Information and Communications, the Communications Authority of Kenya (CAK) gave the bank the green light to roll out its thin SIM cards.

A subscriber identity module or subscriber identification module (SIM), widely known as a SIM card, is an integrated circuit that is intended to securely store the international mobile subscriber identity (IMSI) number and its related key, which are used to identify and authenticate subscribers on mobile telephony devices (such as mobile phones and computers). It is also possible to store contact information on many SIM cards. SIM cards are always used on GSM phones; for CDMA phones, they are only needed for newer LTE-capable handsets. SIM cards can also be used in satellite phones, smart watches, computers, or cameras.

Die SIM-Karte (vom englischen subscriber identity module für „Teilnehmer-Identitätsmodul“) ist eine Chipkarte, die in ein Mobiltelefon eingesteckt wird und zur Identifikation des Nutzers im Netz dient. Mit ihr stellen Mobilfunkanbieter Teilnehmern mobile Telefonanschlüsse und Datenanschlüsse zur Verfügung.


Plot.

In the 24th century, Captain Jean Luc Picard awakens from a nightmare in which he relived his assimilation by the cybernetic Borg. He is contacted by Admiral Hayes, who informs him of a new Borg threat against Earth. Picard's orders are for his ship,, to patrol the Neutral Zone in case of Romulan aggression; Starfleet is worried that Picard is too emotionally involved with the Borg to join the fight.  Learning the fleet is losing the battle, the "Enterprise" crew disobeys orders and heads for Earth, where a single Borg Cube ship holds its own against a group of Starfleet vessels. "Enterprise" arrives in time to assist the crew of and its captain, the Klingon Worf. Picard takes control of the fleet and directs the surviving ships to concentrate their firepower on a seemingly unimportant point on the Borg ship. The Cube is destroyed after launching a smaller sphere ship towards the planet. "Enterprise" pursues the sphere into a temporal vortex. As the sphere disappears, "Enterprise" discovers Earth has been altered – it is now populated entirely by Borg. Realizing the Borg have used time travel to change the past, "Enterprise" follows the sphere through the vortex.  "Enterprise" arrives hundreds of years in its past on April 4, 2063, the day before humanity's first encounter with alien life after Zefram Cochrane's historic warp drive flight; the crew realizes the Borg are trying to prevent first contact. After destroying the Borg sphere, an away team transports down to Cochrane's ship, "Phoenix", in Montana.

Cast.

"First Contact" is the first film in the "Star Trek" film series in which none of the main characters from "" appear. Rather, the main cast of "" play the following characters:  Several of "The Next Generation"s recurring characters also appeared in the film; Dwight Schultz reprised his role of Lieutenant Reginald Barclay and Patti Yasutake briefly appeared as Nurse. Whoopi Goldberg was not asked to return as Guinan, a wise bartender whose homeworld was destroyed by the Borg. Goldberg only learned about the decision through the newspapers. "What can I say? I wanted to do it because I didn't think you could do anything about the Borg without [my character]", she said, "but apparently you can, so they don't need me."  Michael Horton appears as a bloodied and stoic Starfleet Security Officer; his character would be given the name Lt. Daniels in the. Neal McDonough plays

Production.

Development.

In December 1992, Paramount Pictures executives approached "Star Trek: The Next Generation" producer Rick Berman and engaged him to create two films featuring the cast of the television series. Berman decided to develop two screenplays simultaneously, and prioritize the most promising one for the first film. The effort of writers Brannon Braga and Ronald D. Moore was chosen and developed into "Star Trek Generations". Two months after the release of "Generations", Paramount decided to produce the second feature for a winter holiday 1996 release. Paramount wanted Braga and Moore, who had written the "Generations" script and a number of "Next Generation" episodes, to pen the screenplay. Berman told Braga and Moore that he wanted them to think about doing a story involving time travel. Braga and Moore, meanwhile, wanted to use the Borg. "Right on the spot, we said maybe we can do both, the Borg and time travel," Moore recalled. The Borg had not been seen in full force since the fourth-season episode of "The Next Generation", "", and

Design.

"First Contact" was the first "Star Trek" film to make significant use of computer-generated starship models, though physical miniatures were still used for the most important vessels. With the "Enterprise"-D destroyed during the events of "Generations", the task of creating a new starship fell to veteran "Star Trek" production designer Herman Zimmerman. The script's only guide on the appearance of the vessel was the line "the new "Enterprise" sleekly comes out of the nebula". Working with illustrator John Eaves, the designers conceived the new "Sovereign"-class "Enterprise"-E as "leaner, sleeker, and mean enough to answer any Borg threat you can imagine". Braga and Moore intended it to be more muscular and militaryesque. Eaves looked at the structure of previous "Enterprise" iterations, and designed a more streamlined, capable war vessel than the "Enterprise"-D, reducing the neck area of the ship and lengthening the nacelles. Eaves produced 30 to 40 sketches before he found a final design he liked and began making minor changes. Working from blueprints created by Paramount's Rick Sternbach, the model shop at effects house Industrial

Costumes and makeup.

The Starfleet uniforms were redesigned for the film by longtime "Star Trek" costumer Bob Blackman to give a more militaristic feel, with grey padded shoulders and colored undershirts. Since Blackman was also handling the costumes for the television series, non-Starfleet design clothes were delegated to Deborah Everton, a newcomer to "Star Trek" who was responsible for more than 800 costumes during production. Everton was tasked with updating the Borg's costumes to something new, but reminiscent of the television series. The bulky suits were made sleeker and outfitted with fiber optic lights. The time-travel aspect of the story also required period costumes for the mid

Filming.

Principal photography took a more leisurely pace than on "The Next Generation" because of a less hectic schedule; only four pages of script had to be filmed each day, as opposed to eight on the television series. "First Contact" saw the introduction of cinematographer Matthew F. Leonetti to the "Star Trek" franchise; Frakes hired him out of admiration for some of his previous work on films such as "Poltergeist" and "Strange Days". Leonetti was unfamiliar with the "Star Trek" mythos when Frakes approached him; to prepare for the assignment, he studied the previous four films in the franchise, each with a different cinematographer—"" (Donald Peterman), "" (Andrew Laszlo), "" (Hiro Narita), and "Generations" (John Alonzo). The cameraman also spent several days at the sets of "Voyager" and "Deep Space Nine" to observe filming.  Leonetti devised multiple lighting methods for the "Enterprise" interiors for ship standard operations, "Red alert" status, and emergency power. He reasoned that since the ship was being taken over by a foreign entity, it required more dramatic lighting and framing. While much of the footage was shot at 50–70 mm focal lengths using anamorphic lenses, 14 mm spherical lenses were used for Borg's-eye-view shots. Leonetti preferred shooting with long lenses to provide a more claustrophobic feel, but made sure the length did not flatten the image. Handheld cameras were used for battle

Effects.

The majority of "First Contact"s effects were handled by Industrial Light & Magic under the supervision of John Knoll. Smaller effects sequences, such as phaser fire, computer graphics, and transporter effects, were delegated to a team led by visual-effects supervisor David Takemura. Accustomed to directing episodes for the television series, Frakes was frequently reminded by effects artist Terry Frazee to "think big, blow everything up". Most of the effects sequences were planned using low-resolution computer-generated animatics. These rough animated storyboards established length, action and composition, allowing the producers and director to ascertain how the sequences would play out before they were shot.  "First Contact" was the last film to feature a physical model of the "Enterprise". For the ship's dramatic introduction, the effects team combined motion control shots of the "Enterprise" model with a computer-generated background. Sequence supervisor Dennis Turner, who had created "Generations" energy ribbon and specialized in creating natural phenomena, was charged with creating the star cluster, modeled after the Eagle Nebula. The nebular columns and solid areas were modeled with basic wireframe geometry, with surface shaders applied to make the edges of the

Music.

Film composer Jerry Goldsmith scored "First Contact", his third "Star Trek" feature. Goldsmith wrote a sweeping main title which begins with Alexander Courage's "Star Trek" fanfare. Instead of composing a menacing theme to underscore the Borg, Goldsmith wrote a pastoral theme linked to humanity's hopeful first contact. The theme uses a four-note motif used in Goldsmith's "" score, which is used in "First Contact" as a friendship theme and general thematic link. A menacing march with touches of synthesizers was used to represent the Borg. In addition to composing new music, Goldsmith used music from his previous "Star Trek" scores, including his theme from "The Motion Picture". The Klingon theme from the same film is used to represent Worf.  Because of delays with Paramount's "The Ghost and the Darkness", the already-short four-week production schedule was cut to just three weeks. While Berman was concerned about the move, Goldsmith hired his son, Joel, to assist. The young composer provided additional music for the film, writing three cues based on his father's motifs and a total of 22 minutes of music. Joel used variations of his

Themes.

Frakes believes that the main themes of "First Contact"—and "Star Trek" as a whole—are loyalty, friendship, honesty, and mutual respect. This is evident in the film when Picard chooses to rescue Data rather than evacuate the ship with the rest of the crew. The film makes a direct comparison between Picard's hatred of the Borg and refusal to destroy the "Enterprise" and that of Captain Ahab in Herman Melville's novel "Moby-Dick". The moment marks a turning point in the film as Picard changes his mind, symbolized by his putting down his phaser. A similar "Moby-Dick" reference was made in "", and although Braga and Moore did not want to repeat it, they decided it worked so well they could not leave it out.  In "First Contact", the individually inscrutable and faceless Borg fulfil the role of the similarly unreadable whale in Melville's work. Picard, like Ahab, has been hurt by his nemesis, and author Elizabeth Hinds said it makes sense that Picard should "opt for

Release.

1996 marked the 30th anniversary of the "Star Trek" franchise. The franchise was on rocky ground; ratings for "Deep Space Nine" and "Voyager" had shed millions of viewers, being bested by "" as the highest-rated syndicated series. Some fans remained upset Paramount cancelled "The Next Generation" at the height of its popularity, and "Generations" was a commercial success but not critically praised.  "First Contact" was heavily marketed, to an extent not seen since the release of "" in 1979. Several novelizations of the film were written for different age groups. Playmates Toys produced six and nine-inch action figures in addition to ship models and a phaser. Two "making of" television specials premiered on HBO and the Sci-Fi Channel, as well as being promoted during a 30th-anniversary television special on UPN. The theatrical trailer to the film was included on a "Best of Star Trek" music compilation, released at the same time as the "First Contact" soundtrack. Simon & Schuster Interactive developed a Borg-themed video game for Macintosh and Windows personal computers. The game, "", functioned as an interactive movie with scenes filmed at the same time as "First Contact" production. A video game adaptation of the film was also announced by Spectrum HoloByte, and would have taken the form of a real-time strategy game set entirely on the "Enterprise" during the Borg takeover, though it was never released. Paramount heavily marketed the film on the internet via a "First Contact" web site, which averaged 4.4 million hits a week during the film's opening run, the largest amount of traffic ever on a motion-picture site.  The film premiered on November 18, 1996 at Mann's Chinese Theater in Hollywood, Los Angeles. The main cast save Spiner were in attendance, as were Moore, Braga, Jerry Goldsmith, and producer Marty Hornstein. Other "Star Trek" actors present included DeForest Kelley, René Auberjonois, Avery Brooks, Colm Meaney, Armin Shimerman, Terry Farrell, Kate Mulgrew, Roxann Dawson, Jennifer Lien, Robert Duncan McNeill, Ethan Phillips, Tim Russ, Garrett Wang and Robert Picardo. After the screening, 1,500 guests crossed the street to the Hollywood Colonnade, where the interiors had been dressed to match settings from the film: the holodeck nightclub, part of the bridge, a "star room", the Borg hive and the "crash 'n' burn lounge". The film received a royal premiere in the United Kingdom, with the first screening attended by Charles, Prince of Wales.

Box office.

"First Contact" opened in 2,812 theaters beginning November 22, grossing $30.7 million its first week and making it the top movie at the US box office. The film was knocked out of the top place the following week by "101 Dalmatians", earning $25.5 million. The film went on to gross $77 million in its first four weeks, remaining in the top-ten box office during that time. It closed with a US & Canadian gross of $92,027,888

Critical response.

"First Contact" garnered positive reviews on release. Ryan Gilbey of "The Independent" considered the film wise to dispense with the cast of "The Original Series:" "For the first time, a "Star Trek" movie actually looks like something more ambitious than an extended TV show," he wrote. Conversely, critic Bob Thompson felt that "First Contact" was more in the spirit of the 1960s television series than any previous installment. "The Globe and Mail" Elizabeth Renzeti said that "First Contact" succeeded in improving on the "stilted" previous entry in the series, and that it featured a renewed interest in storytelling. Kenneth Turan of the "Los Angeles Times" wrote, ""First Contact" does everything you'd want a "Star Trek" film to do, and it does it with cheerfulness

Home media.

"Star Trek: First Contact" was first released on VHS in late 1997 as one of several titles expected to boost sluggish sales at video retailers. A LaserDisc version was also released. "First Contact" was among the first titles announced for the DVD-alternative rental system Digital Video Express in 1998. It was launched with five other test titles in the select markets of Richmond and San Francisco.  When Paramount announced its first slate of DVD releases in August 1998, "First Contact" was one of the first ten titles released in October, announced in a conscious effort to showcase effects-driven films. This version contained the feature and two trailers, but no other special features. The film was presented in its original 2.35:1 anamorphic aspect ratio, with

Legacy.

"", a 2003 episode of "", depicts the

References.

Notes Bibliography

Star Trek: First Contact is a 1996 American science fiction film directed by Jonathan Frakes (in his motion picture directorial debut) and based on the franchise "Star Trek". It is the eighth film in the "Star Trek" film series, as well as the second to star the cast of "". In the film, the crew of the USS "Enterprise"-E travel back in time from the 24th century to the mid-21st century in order to stop the cybernetic Borg from conquering Earth by changing their past.

Star Trek: Der erste Kontakt (Originaltitel: "Star Trek: First Contact") ist ein US-amerikanischer Science-Fiction-Film aus dem Jahr 1996. Er ist der achte im fiktiven "Star-Trek"-Universum spielende Kinofilm und der zweite, in dem die Raumschiffsbesatzung aus "Raumschiff Enterprise – Das nächste Jahrhundert" im Zentrum der Handlung steht. In dem Film wird die Enterprise im 24. Jahrhundert in einem von den kybernetischen Borg verursachten Zeitstrudel gefangen. Diese sind auf dem Weg zur Erde im 21. Jahrhundert, um die Erde zu assimilieren und das Entstehen der Vereinten Föderation der Planeten zu vereiteln.


Structure.

The sulfate anion consists of a central sulfur atom surrounded by four equivalent oxygen atoms in a tetrahedral arrangement. The symmetry is the same as that of methane. The sulfur atom is in the +6 oxidation state while the four oxygen atoms are each in the −2 state. The sulfate ion carries an overall charge of −2 and it is the conjugate base of the bisulfate (or hydrogen sulfate) ion,, which is in turn the conjugate base of, sulfuric acid. Organic sulfate esters, such as dimethyl sulfate, are covalent compounds and esters of sulfuric acid. The tetrahedral molecular geometry of the sulfate ion is as predicted by VSEPR theory.

Bonding.

The first description of the bonding in modern terms was by Gilbert Lewis in his groundbreaking paper of 1916 where he described the bonding in terms of electron octets around each atom, that is no double bonds and a formal charge of +2 on the sulfur atom.  Later, Linus Pauling used valence bond theory to propose that the most significant resonance canonicals had two pi bonds involving d orbitals. His reasoning was that the charge on sulfur was thus reduced, in accordance with his principle of electroneutrality. The S−O bond length of 149 pm is shorter than the bond lengths in sulfuric acid of 157 pm for S−OH. The double bonding was taken by Pauling to account for the shortness of the S−O bond. Pauling's use of d orbitals provoked a debate on the relative importance of π bonding and bond polarity (electrostatic attraction) in causing the shortening of the S−O bond. The outcome was a broad consensus that d orbitals play a role, but are not as significant as Pauling had believed.  A widely accepted description involving pπ – dπ bonding was initially proposed by D. W. J. Cruickshank. In this model, fully occupied p orbitals on oxygen overlap with empty sulfur d orbitals (principally the d and d). However, in this description, despite there being some π character to the S−O bonds, the bond has significant ionic character. For sulfuric acid, computational analysis (with natural bond orbitals) confirms a clear positive charge on sulfur (theoretically +2.45) and a low 3d occupancy. Therefore, the representation with four single bonds is the optimal Lewis structure rather than the one with two double bonds (thus the Lewis model, not the Pauling model). In this model, the structure obeys the octet rule and the charge distribution is in agreement with the electronegativity of the atoms. The discrepancy between the S−O bond length in the sulfate ion and the S−OH bond length in sulfuric acid is explained by donation of p-orbital electrons from the terminal S=O bonds in sulfuric acid into the antibonding S−OH orbitals, weakening them resulting in the longer bond length of the latter.  However, the bonding representation of Pauling for sulfate and other main group compounds with oxygen is still a common way of representing the bonding in many textbooks. The apparent contradiction can be cleared if one realizes that the covalent double bonds in the Lewis structure in reality represent bonds that are strongly polarized by more than 90% towards the oxygen atom. On the other hand, in the structure with a dipolar bond, the charge is localized as a lone pair on the oxygen.

Preparation.

Methods of preparing metal sulfates include:

Properties.

Many examples of ionic sulfates are known, and many of these are highly soluble in water. Exceptions include calcium sulfate, strontium sulfate, lead(II) sulfate, and barium sulfate, which are poorly soluble. Radium sulfate is the most insoluble sulfate known. The barium derivative is useful in the gravimetric analysis of sulfate: if one adds a solution of, perhaps, barium chloride to a solution containing sulfate ions, the appearance of a white precipitate, which is barium sulfate, indicates that sulfate anions are present.  The sulfate ion can act as a ligand attaching either by one oxygen (monodentate) or by two oxygens as either a chelate or a bridge. An example is the complex <nowiki>[</nowiki>Co(en)(SO)]Br or the neutral metal complex PtSO(P(CH)) where the sulfate ion is acting as a bidentate ligand. The metal–oxygen bonds in sulfate complexes can have significant covalent character.

Uses and occurrence.

Commercial applications.

Sulfates are widely used industrially. Major compounds include:

Occurrence in nature.

Sulfate-reducing bacteria, some anaerobic microorganisms, such as those living in sediment or near deep sea thermal vents, use the reduction of sulfates coupled with the oxidation of organic compounds or hydrogen as an energy source for chemosynthesis.

History.

Some sulfates were known to alchemists. The vitriol salts, from the Latin "vitreolum", glassy, were so-called because they were some of the first transparent crystals known. Green vitriol is iron(II) sulfate heptahydrate, FeSO·7HO; blue vitriol is copper(II) sulfate pentahydrate, CuSO·5HO and white vitriol is zinc sulfate heptahydrate, ZnSO·7HO. Alum, a double sulfate of potassium and aluminium with the formula KAl(SO)·24HO, figured in the development of the chemical industry.

Environmental effects.

Sulfates occur as microscopic particles (aerosols) resulting from fossil fuel and biomass combustion. They increase the acidity of the atmosphere and form acid rain. The anaerobic sulfate-reducing bacteria "Desulfovibrio desulfuricans" and "D. vulgaris" can remove the black sulfate crust that often tarnishes buildings.

Main effects on climate.

The main direct effect of sulfates on the climate involves the scattering of light, effectively increasing the Earth's albedo. This effect is moderately well understood and leads to a cooling from the negative radiative forcing of about 0.4 W/m relative to pre-industrial values, partially offsetting the larger (about 2.4 W/m) warming effect of greenhouse gases. The effect is strongly spatially non-uniform, being largest downstream of large industrial areas.  The first indirect effect is also known as the Twomey effect. Sulfate aerosols can act as cloud condensation nuclei and this leads to greater numbers of smaller droplets of water. Many smaller droplets can diffuse light more efficiently than a few larger droplets.  The second indirect effect is the further knock-on effects of having more cloud condensation nuclei. It is proposed that these include the suppression of drizzle, increased cloud height, to facilitate cloud formation at low humidities and longer cloud lifetime. Sulfate may also result in changes in the particle size distribution, which can affect the clouds radiative properties in ways that are not fully understood. Chemical effects such as the dissolution of soluble gases and slightly soluble substances, surface tension depression by organic substances and accommodation coefficient changes are also included in the second indirect effect.  The indirect effects probably have a cooling effect, perhaps up to 2 W/m, although the uncertainty is very large. Sulfates are therefore implicated in global dimming. Sulfate is also the major contributor to stratospheric aerosol formed by oxidation of sulfur dioxide injected into the stratosphere by impulsive volcanoes such as the 1991 eruption of Mount Pinatubo in the Philippines. This aerosol exerts a cooling effect on climate during its 1-2 year lifetime in the stratosphere.

Hydrogen sulfate (bisulfate).

The conjugate base of sulfuric acid (HSO)—a dense, colourless, oily, corrosive liquid—is the hydrogen sulfate ion (), also called the bisulfate ion. Sulfuric acid is classified as a strong acid; in aqueous solutions it ionizes completely to form hydronium ions (HO) and hydrogen sulfate (). In other words, the sulfuric acid behaves as a Brønsted–Lowry acid and is deprotonated. Bisulfate has a molar mass of 97.078 g/mol. It has a valency of 1. An example of a salt containing the group is sodium bisulfate, NaHSO. In dilute solutions the hydrogen sulfate ions also dissociate, forming more hydronium ions and sulfate ions (). The CAS registry number for hydrogen sulfate is 14996-02-2.

The sulfate or sulphate (see spelling differences) ion is a polyatomic anion with the empirical formula. Sulfate is the spelling recommended by IUPAC, but sulphate is used in British English. Salts, acid derivatives, and peroxides of sulfate are widely used in industry. Sulfates occur widely in everyday life. Sulfates are salts of sulfuric acid and many are prepared from that acid.

Sulfate sind Salze oder Ester der Schwefelsäure. Die Salze enthalten das Sulfat-Anion [SO] bzw. das Hydrogensulfat-Anion [HSO]. Die Ester der Schwefelsäure haben die allgemeine Formel R−O−SO−O−R', dabei sind R und/oder R' organische Reste.


Etymology and history.

The word "gypsum" is derived from the Greek word γύψος ("gypsos"), "plaster". Because the quarries of the Montmartre district of Paris have long furnished burnt gypsum (calcined gypsum) used for various purposes, this dehydrated gypsum became known as plaster of Paris. Upon addition of water, after a few tens of minutes plaster of Paris becomes regular gypsum (dihydrate) again, causing the material to harden or "set" in ways that are useful for casting and construction.  Gypsum was known in Old English as "spærstān", "spear stone", referring to its crystalline projections. (Thus, the word spar in mineralogy is by way of comparison to gypsum, referring to any non-ore mineral or crystal that forms in spearlike projections). In the mid-18th century, the German clergyman and agriculturalist Johann Friderich Mayer investigated and publicized gypsum's use as a fertilizer. Gypsum may act as a source of sulfur for plant growth, and in the early 19th century, it was regarded as an almost miraculous fertilizer. American farmers were so anxious to acquire it that a lively smuggling trade with Nova Scotia evolved, resulting in the so-called "Plaster War" of 1820. In the 19th century, it was also known as lime sulfate or sulfate of lime.

Physical properties.

Gypsum is moderately water-soluble (~2.0–2.5 g/l at 25 °C) and, in contrast to most other salts, it exhibits retrograde solubility, becoming less soluble at higher temperatures. When gypsum is heated in air it loses water and converts first to calcium sulfate hemihydrate, (bassanite, often simply called "plaster") and, if heated further, to anhydrous calcium sulfate (anhydrite). As for anhydrite, its solubility in saline solutions and in brines is also strongly dependent on NaCl (common table salt) concentration.  Gypsum crystals are found to contain anion water and hydrogen bonding.

Crystal varieties.

Gypsum occurs in nature as flattened and often twinned crystals, and transparent, cleavable masses called selenite. Selenite contains no significant selenium; rather, both substances were named for the ancient Greek word for the Moon.  Selenite may also occur in a silky, fibrous form, in which case it is commonly called "satin spar". Finally, it may also be granular or quite compact. In hand-sized samples, it can be anywhere from transparent to opaque. A very fine-grained white or lightly tinted variety of gypsum, called alabaster, is prized for ornamental work of various sorts. In arid areas, gypsum can occur in a flower-like form, typically opaque, with embedded sand grains called desert rose. It also forms some of the largest crystals found in nature, up to long, in the form of selenite.

Occurrence.

Gypsum is a common mineral, with thick and extensive evaporite beds in association with sedimentary rocks. Deposits are known to occur in strata from as far back as the Archaean eon. Gypsum is deposited from lake and sea water, as well as in hot springs, from volcanic vapors, and sulfate solutions in veins. Hydrothermal anhydrite in veins is commonly hydrated to gypsum by groundwater in near-surface exposures. It is often associated with the minerals halite and sulfur. Gypsum is the most common sulfate mineral. Pure gypsum is white, but other substances found as impurities may give a wide range of colors to local deposits.  Because gypsum dissolves over time in water, gypsum is rarely found in the form of sand. However, the unique conditions of the White Sands National Park in the US state of New Mexico have created a expanse of white gypsum sand, enough to supply the US construction industry with drywall for 1,000 years. Commercial exploitation of the area, strongly opposed by area residents, was permanently prevented in 1933 when President Herbert Hoover declared the gypsum dunes a protected national monument.  Gypsum is also formed as a by-product of sulfide oxidation, amongst others by pyrite oxidation, when the sulfuric acid generated reacts with calcium carbonate. Its presence indicates oxidizing conditions. Under reducing conditions, the sulfates it contains can be reduced back to sulfide by sulfate-reducing bacteria. Electric power stations burning coal with flue gas desulfurization produce large quantities of gypsum as a byproduct from the scrubbers.  Orbital pictures from the Mars Reconnaissance Orbiter (MRO) have indicated the existence of gypsum dunes in the northern polar region of Mars, which were later confirmed at ground level by the Mars Exploration Rover (MER) "Opportunity".

Mining.

Commercial quantities of gypsum are found in the cities of Araripina and Grajaú in Brazil; in Pakistan, Jamaica, Iran (world's second largest producer), Thailand, Spain (the main producer in Europe), Germany, Italy, England, Ireland and Canada and the United States. Large open pit quarries are located in many places including Fort Dodge, Iowa, which sits on one of the largest deposits of gypsum in the world, and Plaster City, California, United States, and East Kutai, Kalimantan, Indonesia. Several small mines also exist in places such as Kalannie in Western Australia, where gypsum is sold to private buyers for additions of calcium and sulfur as well as reduction of aluminum toxicities on soil for agricultural purposes.  Crystals of gypsum up to long have been found in the caves of the Naica Mine of Chihuahua, Mexico. The crystals thrived in the cave's extremely rare and stable natural environment. Temperatures stayed at, and the cave was filled with mineral-rich water that drove the crystals' growth. The largest of those crystals weighs and is around 500,000 years old.

Synthesis.

Synthetic gypsum is recovered via flue-gas desulfurization at some coal-fired power plants. It can be used interchangeably with natural gypsum in some applications.  Gypsum also precipitates onto brackish water membranes, a phenomenon known as mineral salt scaling, such as during brackish water desalination of water with high concentrations of calcium and sulfate. Scaling decreases membrane life and productivity. This is one of the main obstacles in brackish water membrane desalination processes, such as reverse osmosis or nanofiltration. Other forms of scaling, such as calcite scaling, depending on the water source, can also be important considerations in distillation, as well as in heat exchangers, where either the salt solubility or concentration can change rapidly.  A new study has suggested that the formation of gypsum starts as tiny crystals of a mineral called bassanite (CaSO·HO). This process occurs via a three-stage pathway:

Occupational safety.

People can be exposed to gypsum in the workplace by breathing it in, skin contact, and eye contact.

United States.

The Occupational Safety and Health Administration (OSHA) has set the legal limit (permissible exposure limit) for gypsum exposure in the workplace as TWA 15 mg/m for total exposure and TWA 5 mg/m for respiratory exposure over an 8-hour workday. The National Institute for Occupational Safety and Health (NIOSH) has set a recommended exposure limit (REL) of TWA 10 mg/m for total exposure and TWA 5 mg/m for respiratory exposure over an 8-hour workday.

Uses.

Gypsum is used in a wide variety of applications:

Gypsum is a soft sulfate mineral composed of calcium sulfate dihydrate, with the chemical formula CaSO·2HO. It is widely mined and is used as a fertilizer and as the main constituent in many forms of plaster, blackboard/sidewalk chalk, and drywall. A massive fine-grained white or lightly tinted variety of gypsum, called alabaster, has been used for sculpture by many cultures including Ancient Egypt, Mesopotamia, Ancient Rome, the Byzantine Empire, and the Nottingham alabasters of Medieval England. Gypsum also crystallizes as translucent crystals of selenite. It also forms as an evaporite mineral and as a hydration product of anhydrite.

Gips, geologisch auch als Gipsspat bekannt, ist ein sehr häufig vorkommendes Mineral aus der Mineralklasse der „Sulfate (und Verwandte)“ mit der chemischen Zusammensetzung Ca[SO]·2HO und damit chemisch gesehen wasserhaltiges Calciumsulfat oder auch Calciumsulfat-Dihydrat.