AcharyaChanakya/simple-wikipedia huggingface dataset:
Grignard reactions will not work if water is present; water causes the reagent to rapidly decompose. So, most Grignard reactions occur in solvents such as anhydrous diethyl ether or tetrahydrofuran (THF), because the oxygen in these solvents stabilizes the magnesium reagent. The reagent may also react with oxygen present in the atmosphere. This will insert an oxygen atom between the carbon base and the magnesium halide group. Usually, this side-reaction may be limited by the volatile solvent vapors displacing air above the reaction mixture. However, chemists may perform the reactions in nitrogen or argon atmospheres. In small scale reactions, the solvent vapors do not have enough space to protect the magnesium from oxygen.
Grignard reagents are formed by the action of an alkyl or aryl halide on magnesium metal. The reaction is conducted by adding the organic halide to a suspension of magnesium in an ether, which provides ligands required to stabilize the organomagnesium compound. Typical solvents are diethyl ether and tetrahydrofuran. Oxygen and protic solvents such as water or alcohols are not compatible with Grignard reagents. The reaction proceeds through single electron transfer.
Grignard reactions often start slowly. First, there is an induction period during which reactive magnesium becomes exposed to the organic reagents. After this induction period, the reactions can be highly exothermic. Alkyl and aryl bromides and iodides are common substrates. Chlorides are also used, but fluorides are generally unreactive, except with specially activated magnesium, such as Rieke magnesium.
Many Grignard reagents, such as methylmagnesium chloride, phenylmagnesium bromide, and allylmagnesium bromide are available commercially in tetrahydrofuran or diethyl ether solutions.
Using the Schlenk equilibrium, Grignard reagents form varying amounts of diorganomagnesium compounds (R = organic group, X = halide):
Many methods have been developed to initiate Grignard reactions that are slow to start. These methods weaken the layer of MgO that covers the magnesium. They expose the magnesium to the organic halide to start the reaction that makes the Grignard reagent.
Mechanical methods include crushing of the Mg pieces "in situ", rapid stirring, or using ultrasound (sonication) of the suspension. Iodine, methyl iodide, and 1,2-dibromoethane are commonly employed activating agents. Chemists use 1,2-dibromoethane because its action can be monitored by the observation of bubbles of ethylene. Also, the side-products are innocuous:
The amount of Mg consumed by these activating agents is usually insignificant.
The addition of a small amount of mercuric chloride will amalgamate the surface of the metal, allowing it to react.
Grignard reagents are produced in industry for use in place, or for sale. As with at bench-scale, the main problem is that of initiation. A portion of a previous batch of Grignard reagent is often used as the initiator. Grignard reactions are exothermic; this exothermicity must be considered when a reaction is scaled-up from laboratory to production plant.
Grignard reagents will react with a variety of carbonyl derivatives.
The most common application is for alkylation of aldehydes and ketones, as in this example:
Note that the acetal function (a masked carbonyl) does not react.
Such reactions usually involve a water-based (aqueous) acidic workup, though this is rarely shown in reaction schemes. In cases where the Grignard reagent is adding to a prochiral aldehyde or ketone, the Felkin-Anh model or Cram's Rule can usually predict which stereoisomer will form.
In addition, Grignard reagents will react with electrophiles.
Another example is making salicylaldehyde (not shown above). First, bromoethane reacts with Mg in ether. Second, phenol in THF converts the phenol into Ar-OMgBr. Third, benzene is added in the presence of paraformaldehyde powder and triethylamine. Fourth, the mixture is distilled to remove the solvents. Next, 10% HCl is added. Salicylaldehyde will be the major product as long as everything is very dry and under inert conditions. The reaction works also with iodoethane instead of bromoethane.
The Grignard reagent is very useful for forming carbon–heteroatom bonds.
A Grignard reagent can also be involved in coupling reactions. For example, nonylmagnesium bromide reacts with methyl "p"-chlorobenzoate to give "p"-nonylbenzoic acid, in the presence of Tris(acetylacetonato)iron(III), often symbolized as Fe(acac), after workup with NaOH to hydrolyze the ester, shown as follows. Without the Fe(acac), the Grignard reagent would attack the ester group over the aryl halide.
For the coupling of aryl halides with aryl Grignards, nickel chloride in tetrahydrofuran (THF) is also a good catalyst. Additionally, an effective catalyst for the couplings of alkyl halides is dilithium tetrachlorocuprate (LiCuCl), prepared by mixing lithium chloride (LiCl) and copper(II) chloride (CuCl) in THF. The Kumada-Corriu coupling gives access to [substituted] styrenes.
The oxidation of a Grignard reagent with oxygen takes place through a radical intermediate to a magnesium hydroperoxide. Hydrolysis of this complex yields hydroperoxides and reduction with an additional equivalent of Grignard reagent gives an alcohol.
A reaction of Grignards with oxygen in presence of an alkene makes an ethylene extended alcohol. These are useful in synthesizing larger compounds. This modification requires aryl or vinyl Grignard reagents. Adding just the Grignard and the alkene does not result in a reaction, showing that the presence of oxygen is essential. The only drawback is the requirement of at least two equivalents of Grignard reagent in the reaction. This can addressed by using a dual Grignard system with a cheap reducing Grignard reagent such as n-butylmagnesium bromide.
Grignard reagents are nucleophiles in nucleophilic aliphatic substitutions for instance with alkyl halides in a key step in industrial Naproxen production:
In the Boord olefin synthesis, the addition of magnesium to certain β-haloethers results in an elimination reaction to the alkene. This reaction can limit the utility of Grignard reactions.
Grignard degradation at one time was a tool in structure identification (elucidation) in which a Grignard RMgBr formed from a heteroaryl bromide HetBr reacts with water to Het-H (bromine replaced by a hydrogen atom) and MgBrOH. This hydrolysis method allows the determination of the number of halogen atoms in an organic compound. In modern usage, Grignard degradation is used in the chemical analysis of certain triacylglycerols.
An example of the Grignard reaction is a key step in the industrial production of Tamoxifen. (Tamoxifen is currently used for the treatment of estrogen receptor positive breast cancer in women.):
Peach (disambiguation)
Peach can mean:
Giant Magellan Telescope
The Giant Magellan Telescope (GMT) will be the world's largest telescope when it is completed in 2025. Instead of one large mirror, the GMT will have seven separate mirrors working together. This will mean its collecting area is bigger than the actual mirror surfaces. It will be made of seven diameter mirror parts. It will have a the resolving power of a mirror. Its collecting area will be the same as a mirror. The telescope will have over four times the ability to gather light than existing telescopes. It will produce images up to ten times clearer than the Hubble Space Telescope. It will cost $700 million.
The location of the telescope is the Las Campanas Observatory, which is also the site of the Magellan Telescopes, some northeast of La Serena, Chile. This area has clear weather for most of the year. The night sky in most of the surrounding Atacama Desert region is free from atmospheric pollution. With few cities nearby this is probably one of the places least affected by light pollution. All of this makes the area one of the best spots on Earth for long-term astronomical observation.
The telescope is unique because it will use seven mirror sections, each in diameter. These segments will then be arranged to form a single optical surface. This is difficult as the surface of the outer six mirror segments is not radially symmetrical (that is, they are off-axis). This requires a small change in the way mirrors are usually polished. All seven mirrors will be arranged so that the reflecting surface of each of them is on a common axis. One mirror will be in the center and the other six arranged symmetrically around the center. A focal plane will be on-axis with the entire assembly. The plan is to build seven identical off-axis mirrors. The spare mirror has been made to replace a mirror when it needs recoating, a 1–2 week (per segment) process required every 1–2 years.
The Steward Observatory, at the University of Arizona, is making the mirrors in a laboratory beneath the university's football stadium. It is using a rotating furnace to make the mirror. The casting of the first mirror was completed on November 3, 2005. But the time-consuming shaping and polishing will be completed in the autumn of 2011.
The telescope will make use of adaptive optics.
The following is a list of the group which is developing the telescope.
George P. Mitchell, founder of Mitchell Energy & Development Corp., and The Cynthia and George Mitchell Foundation are giving $25 million to help pay for the telescope.
Stinging nettle
Stinging nettles ("Urtica dioica") are a type of plant which have stinging defensive hairs on the leaves and stems. Stinging nettles can be found in America, Europe and Asia.
The hairs inject histamine and other chemicals that produce a stinging sensation when contacted by humans and other animals. Soaking stinging nettles in water or cooking removes the stinging chemicals from the plant, which allows them to be handled and eaten without injury.
The plant has been used as medicine, food, tea and fibre. Nettles are sometimes used in cheesemaking, as nettle soup or as substitute for spinach. Its stems contain a bast fibre that is used for the same purposes as linen. Nettles have been used to make clothing for 2,000 years.
Stinging nettles are important food plants for several butterflies, like the peacock butterfly and the small tortoiseshell. Also some deers and other animals eat the plant, preferred the leaf shot.
The Ferrari F50 is a sports car made by Ferrari in 1995. It was created to celebrate the company's 50th anniversary. The car has two doors. It is a two-seated convertible with a removable hardtop. It has a 4.7 L V12 engine that was based on the 3.5 L V12 used in the 1992 Ferrari F92A Formula One car.
Only 349 Ferrari F50's were made. This was because Ferrari wanted it to be rare. The last F50 was produced in Maranello, Italy in July 1997.
The Ferrari F50 can travel at over 200 miles per hour.
Mass spectrum
A mass spectrum is an intensity versus "m/z" (mass-to-charge ratio) plot that represents a chemical analysis. The mass spectrum of a sample is a pattern representing the distribution of ions by mass (more correctly: mass-to-charge ratio) in a sample. It is a histogram usually made using an instrument called a mass spectrometer. Not all mass spectra of a given substance are the same. It can depend on the operating conditions of the instrument. For example, some mass spectrometers break the analyte molecules into many pieces; others observe the intact molecular masses with little fragmentation. A mass spectrum can represent many different types of information based on the type of mass spectrometer and the specific experiment; however, all plots of intensity vs. mass-to-charge are called "mass spectra".
Common fragmentation processes for organic molecules are the McLafferty rearrangement and alpha cleavage.
In the past, chemists with PhD degrees were needed to interpret mass spectra. Today, computer programs read the data and identify the compounds in a sample.
Stuntman (video game)
Stuntman is a racing/action video game that was published by Infogrames and Atari. It was released for the PlayStation 2 and the Game Boy Advance systems. The game is also featured as a mobile phone game which could be downloaded. Stuntman was followed by the 2007 sequel, . The game received positive reviews, GameSpot gave it a 8.0 out of 10 and IGN gave it a 8.6 out of 10.
Eh, Eh (Nothing Else I Can Say)
SN2 reaction
The S2 reaction (also known as bimolecular nucleophilic substitution) is a substitution reaction in organic chemistry. It is a type of nucleophilic substitution, where a lone pair from a nucleophile attacks an electron deficient electrophilic center and bonds to it. This expels another group called a "leaving group". So, the incoming group replaces the leaving group in one step. Since two reacting species are involved in the slow, rate-determining step of the reaction, this leads to the name "bimolecular nucleophilic substitution", or "S2". Among inorganic chemists, the S2 reaction is often known as the "interchange mechanism".
The reaction most often occurs at an aliphatic sp carbon center with an electronegative, stable leaving group attached to it - 'X' - frequently a halide atom. The breaking of the C-X bond and the formation of the new C-Nu bond occur simultaneously to form a transition state in which the carbon under nucleophilic attack is pentacoordinate, and approximately sp hybridized. The nucleophile attacks the carbon at 180° to the leaving group, since this provides the best overlap between the nucleophile's lone pair and the C-X σ* antibonding orbital. The leaving group is then pushed off the opposite side and the product is formed.
If the substrate under nucleophilic attack is chiral, this can lead, although not necessarily, to an inversion of stereochemistry, called the Walden inversion.
In an example of the S2 reaction, the attack of OH (the nucleophile) on a bromoethane (the electrophile) results in ethanol, with bromide ejected as the leaving group:
A S2 reaction occurs if the backside route of attack is not blocked by other atoms in the molecule (sterically hindered by substituents on the substrate). So, this mechanism usually occurs at an unhindered primary carbon center. If there is steric crowding on the substrate near the leaving group, such as at a tertiary carbon center, the substitution will use an S1 rather than an S2 mechanism, (an S1 would also be more likely with blocked molecules because a sufficiently stable carbocation intermediary could be formed.)
In coordination chemistry, associative substitution proceeds by a similar mechanism as S2.
Four factors affect the rate of the reaction:
The rate of an S2 reaction is second order, as the rate-determining step depends on the nucleophile concentration, <nowiki>[</nowiki>Nu<nowiki>]</nowiki> as well as the concentration of substrate, <nowiki>[RX]</nowiki>.
This is a key difference between the S1 and S2 mechanisms. In the S1 reaction, the nucleophile attacks after the rate-limiting step is over. But in a S2 reaction, the nucleophile forces off the leaving group in the limiting step. In other words, the rate of S1 reactions depend only on the concentration of the substrate while the S2 reaction rate depends on the concentration of both the substrate and nucleophile. In cases where both mechanisms are possible (for example at a secondary carbon center), the mechanism depends on solvent, temperature, concentration of the nucleophile or on the leaving group.
S2 reactions are generally favored in primary alkyl halides or secondary alkyl halides with an aprotic solvent. They occur at a negligible rate in tertiary alkyl halides due to steric hindrance.
S2 and S1 are two extremes of a sliding scale of reactions. It is possible to find many reactions which exhibit both S2 and S1 character in their mechanisms. For instance, it is possible to get a contact ion pairs formed from an alkyl halide in which the ions are not fully separated. When these undergo substitution the stereochemistry will be inverted (as in S2) for many of the reacting molecules but a few may show retention of configuration. S2 reactions are more common than S1 reactions.
A common side reaction taking place with S2 reactions is E2 elimination: the incoming anion can act as a base rather than as a nucleophile, removing a proton and leading to formation of the alkene. This effect can be demonstrated in the gas-phase reaction between a sulfonate and a simple alkyl bromide taking place inside a mass spectrometer:
With ethyl bromide, the reaction product is predominantly the substitution product. As steric hindrance around the electrophilic center increases, as with isobutyl bromide, substitution is disfavored and elimination is the predominant reaction. Other factors favoring elimination are the strength of the base. With the less basic benzoate substrate, isopropyl bromide reacts with 55% substitution. In general, gas phase reactions and solution phase reactions of this type follow the same trends, even though in the first, solvent effects are dropped.
A development attracting attention in 2008 concerns a S2 roundabout mechanism observed in a gas-phase reaction between chloride ions and methyl iodide with a special technique called "crossed molecular beam imaging". When the chloride ions have sufficient velocity, the energy of the resulting iodide ions after the collision is much lower than expected, and it is theorized that energy is lost as a result of a full roundabout of the methyl group around the iodine atom before the actual displacement takes place.
SN1 reaction
The S1 reaction is a substitution reaction in organic chemistry. "S" stands for nucleophilic substitution and the "1" represents the fact that the rate-determining step involves only one molecule (unimolecular). The reaction involves a carbocation intermediate. Some common S1 reactions are of secondary or tertiary alkyl halides under strongly basic conditions or, under strongly acidic conditions, with secondary or tertiary alcohols. With primary alkyl halides, the alternative S2 reaction occurs. Among inorganic chemists, the S1 reaction is often known as the "dissociative mechanism". Christopher Ingold et al. first proposed the reaction mechanism in 1940.
An example of a reaction taking place with an S1 reaction mechanism is the hydrolysis of tert-butyl bromide with water to form tert-butyl alcohol:
This S1 reaction takes place in three steps:
Because the first step is the bottleneck or "rate-determining step" chemists classify the entire reaction mechanism as S1. Only one molecule is needed for that step.
Sometimes a molecule can react using either an S1 or an S2 mechanism.
The S1 mechanism will win this competition when the central carbon atom is surrounded by bulky groups because such groups sterically hinder the S2 reaction. Additionally, bulky substituents on the central carbon increase the rate of carbocation formation because of the relief of steric strain that occurs. The resultant carbocation is also stabilized by both inductive stabilization and hyperconjugation from attached alkyl groups. The Hammond-Leffler postulate says that this too will increase the rate of carbocation formation. The S1 mechanism therefore dominates in reactions at tertiary alkyl centers and is further observed at secondary alkyl centers in the presence of weak nucleophiles.
An example of a reaction proceeding in a S1 way is the synthesis of "2,5-dichloro-2,5-dimethylhexane" from the corresponding diol with concentrated hydrochloric acid:
As the alpha and beta substitutions increase with respect to leaving groups, the reaction is diverted from S2 to S1.
The carbocation intermediate formed in the reaction's rate limiting step is an "sp" hybridized carbon with trigonal planar molecular geometry. This allows two different paths for the nucleophilic attack, one on either side of the planar molecule. If neither path is preferentially favored, these two paths will be used equally, yielding a racemic mix of enantiomers if the reaction takes place at a stereocenter. This is illustrated below in the S1 reaction of S-3-chloro-3-methylhexane with an iodide ion, which yields a racemic mixture of 3-iodo-3-methylhexane:
However, an excess of one stereoisomer can be observed, as the leaving group can remain close to the carbocation intermediate for a short time and block nucleophilic attack. This is very different than the S2 mechanism, which does not mix the stereochemistry of the product (a stereospecific mechanism). The S2 mechanism always inverts the molecule's stereochemistry.
Two common side reactions are elimination reactions and carbocation rearrangement. If the reaction is performed under warm or hot conditions (which favor an increase in entropy), E1 elimination is likely to predominate, leading to formation of an alkene. At lower temperatures, S1 and E1 reactions are competitive reactions. So, it becomes difficult to favor one over the other. Even if the reaction is performed cold, some alkene may be formed. If an attempt is made to perform an S1 reaction using a strongly basic nucleophile such as hydroxide or methoxide ion, the alkene will again be formed, this time via an E2 elimination. This will be especially true if the reaction is heated. Finally, if the carbocation intermediate can rearrange to a more stable carbocation, it will give a product derived from the more stable carbocation rather than the simple substitution product.
Solvents will change the reaction rate. Since the S1 reaction involves formation of an unstable carbocation intermediate in the rate-determining step, anything that can help this will speed up the reaction. The normal solvents of choice are both "polar" (to stabilize ionic intermediates in general) and "protic" (to solvate the leaving group in particular). Typical polar protic solvents include water and alcohols, which will also act as nucleophiles.
The Y scale correlates solvolysis reaction rates of any solvent (k) with that of a standard solvent (80% v/v ethanol/water) (k) through
with "m" a reactant constant ("m" = 1 for tert-butyl chloride),
For example 100% ethanol gives Y = −2.3, 50% ethanol in water Y = +1.65 and 15% concentration Y = +3.2.
SC Austria Lustenau
SC Austria Lustenau is a football club from Lustenau, Vorarlberg. The club is playing in the Erste Liga, the second division in Austria.
The club was founded in June 1914 as football department of Turnerbund Lustenau and was named FA Turnerbund Lustenau. This name had the club till 1936. For not having a football assosiation in Vorarlberg the club only played friendly matches. During the time of First World War there were no matches. In 1920 the club started in a regular championship. The first success was the Vorarlberg championship in the 1929/30 season. They were qualified for the Austrian Amateur Championship and reached the final versus Kremser SC.
In 1936 the club left the Turnerbund Lustenau and became a club of its own. The were renamed to SC Austria Lustenau. In the following years they reached several titels. In 1994 they won the Regionalliga West and were promoted to the First League, the second division in Austrian football. From 1997 to 2000 they played in the Bundesliga, the top division of Austrias football.
The biggest success so far was the Cup final in 2010/11. Austria Lustenau was the first club from Vorarlberg which ever reached a Cup final. The match was lost against SV Ried.
"As of 12 August 2011."
Stuntman: Ignition
Stuntman: Ignition is a racing/action video game that was published by THQ and was developed by Paradigm Entertainment. It was released for the PlayStation 2, PlayStation 3 and the Xbox 360 systems. Stuntman: Ignition was the sequel to the 2002 video game, Stuntman. The game received positive reviews, GameSpot gave it a 7.5 out of 10 and IGN gave it a 7.1 out of 10.
Kazunori Yamauchi
Cradle of Humankind
The Cradle of Humankind is a World Heritage Site. It was first named by UNESCO in 1999. The site is about 50 kilometres northwest of Johannesburg, South Africa in the Gauteng province, and occupies .
The site's limestone caves, including the Sterkfontein Caves, were where fossils were found. A 2.3-million year-old fossil "Australopithecus africanus" (nicknamed 'Mrs. Ples') was found in 1947 by Robert Broom and John T. Robinson. The find followed the 1924 discovery of the juvenile "Australopithecus africanus" skull, 'Taung Child', by Raymond Dart, at Taung in the North West Province of South Africa, where excavations still continue.
The name "Cradle of Humankind" reflects the fact that the site has produced a large number, as well as some of the oldest, hominid fossils ever found, some dating back as far as 3.5 million years ago. Sterkfontein alone has produced more than a third of early hominid fossils ever found.
The remains of several partial skeletons of a previously unknown Australopithecan species were found in 2008 near Johannesburg. They have been dated to about two million year ago (mya). A recent re-examination of two partial skeletons of "Australopithecus sediba" has led to its identification as close to the origin of the genus "Homo". Not all palaeoanthropologists agree this is a new species.
A new analysis shows this species had a human-like pelvis, hands and teeth, and a chimpanzee-like foot. In six separate research reports, palaeontologists reported on the anatomy of a juvenile male skeleton, MH1, a female skeleton, known as MH2, and an isolated adult tibia or shinbone, known as MH4. The findings suggest that some species of australopithecine climbed trees, some walked on the ground, and some did both.
Colleagues in England investigated the teeth. Like other parts of the skeleton, the teeth are a mosaic of primitive and human-like features.
Lokomotiv Yaroslavl
Lokomotiv Yaroslavl () is a Russian professional ice hockey team playing in the Kontinental Hockey League (KHL).
The Lokomotiv Yaroslavl plane crash occurred on Wednesday, September 7, 2011 at 16:02 local time, when a Yak-Service Yakolev Yak-42 airplane, with the professional ice hockey team and coaching staff of Lokomotiv Yaroslavl of the Kontinental Hockey League, crashed near Yaroslavl, Russia. The team was going to Minsk, Belarus, to start the 2011-12 KHL season against Dinamo Minsk. 44 out of the 45 people on board were confirmed dead, one crew member survived.
Russian Open Championship winner (3): 1996–97, 2001–02, 2002–03
Runners-up of KHL (2): 2007–08, 2008–09
Bronze medal winner of Russian Open Championship and KHL (4): 1997–98, 1998–99, 2004-2005, 2010–11
Runners-up of IIHF Continental Cup : 2003
Bronze medal of Spengler Cup: 2003
"Note: GP = Games played, W = Wins, L = Losses, OTL = Overtime/Shootout Losses, Pts = Points, GF = Goals for, GA = Goals against"
Overhand knot
Knot theory
A Fabergé egg is one of the jewelled eggs made by Peter Carl Fabergé and his company between 1885 and 1917.
The most famous are those made for the Russian Tsars Alexander III and Nicholas II. They were Easter gifts for their wives and mothers, and are called the 'Imperial' Fabergé eggs. The House of Fabergé made about 52 imperial eggs, of which 46 have survived. Two more were planned for Easter 1918, but were not delivered, due to the Russian Revolution.
Below is a list of the eggs made for the Russian imperial family.
Faberge also made eggs for Alexander Kelch, a Siberian gold mine industrialist, as gifts for his wife Barbara (Varvara) Kelch-Bazanova. Most are copies of other eggs.
Primary care doctor
Anthology (Selena album)
Anthology was a greatest hits album by Selena. The album included remixed songs from Selena's early music career. Two EPs were released as a promotion. The album sold over 1,200,000 copies.
"Mariachi"
"Cumbia"
Two EPs were released. Both of them contained five songs each.
All My Hits/Todos Mis Exitos
All My Hits Vol. 2
All My Hits/Todos Mis Exitos Vol. 2 was the second series of the "All My Hits" collection. It was a greatest hits album by Selena. The album included a heart-necklace for fans. The album sold over 400,000 copies in the United States.
Ones (album)
Jammu Kashmir Liberation Front
JKLF seeks independence of Jammu and Kashmir state from both India and Pakistan.
The JKLF claims that they are not Islamist, but are nationalist, and opposes the emergence of the territories into either Pakistan or India but rather wants the region of Kashmir to separate from the three countries and become independent.
In 1982 branches were established in Pakistan-administered Kashmir, Pakistan and in 1987 in Indian-administered Kashmir (Jammu and Kashmir).
Mirador de la Flor
Marie Joséphine of Savoy
Marie Joséphine of Savoy (Maria Giuseppina Luigia; 2 September 1753 – 13 November 1810) was the wife of the future Louis XVIII of France. She was a princess of Savoy by birth, became the titular Queen consort, and was known by her title: Her Royal Highness, Countess of Provence ("comtesse de Provence").
She was born at the Royal Palace of Turin on 2 September 1753 and was the third child and second daughter of Victor Amadeus and his wife the Spanish Infanta Maria Antonia of Spain. At the time of her birth her grandfather, Charles Emmanuel III of Sardinia, was the King of Sardinia.
Maria Giuseppina was engaged to the French Prince Louis Stanislas of France. He was known as the Count of Provence. They were married on 16 April 1771 "by proxy" in the Turin. They were married in person on 14 May 1771 at the Palace of Versailles. A luxurious ball followed the wedding on 20 May. She was considered to be ugly. Louis Stanislas hated his wife. We know today that these rumors were created by those who supported Marie Antoinette as a rivalry soon emerged after the youngest brother 'comte d'Artois', married the Comtesse's sister, thereby bringing yet another Savoyard princess to Versailles and creating an Italian party at court.
In France she was known as Marie Joséphine de Savoie. She had a high rank at court as her husband was a grandson of the reiging king. She was a cousin of the ill-fated "Princess of Lamballe" who was instrumental in the arrangement of the marriage. At the death of her husband’s grandfather Louis XV in 1774, her brother-in-law succeeded as Louis XVI. She became pregnant in 1774 and 1781, but both pregnancies ended in miscarriage. In 1791 Marie Joséphine went to Germany. During the period of exile, the Count and Countess fought constantly. Some historians have suggested Marie Joséphine's possible lesbian relationship with a lady-in-waiting as the primary cause for discord between the couple.
Marie Joséphine died of an edema at Hartwell House, English residence of the exiled French royal family. Marie Joséphine was laid to rest in the Lady Chapel of Westminster Abbey. Her body was removed a year later on Louis's orders and buried in the Kingdom of Sardinia; today in Cagliari Cathedral.
Islam in Palestine
Islam is the religion of the majority of the Palestinian population residing in the Palestinian territories, with Muslims comprising 75% of the population of the West Bank, and 99% of the population of the Gaza Strip.
Jerusalem is Islam's third holiest city after Mecca and Medina in Saudi Arabia. The "Haram al Sharif" (Temple Mount) of Jerusalem is believed by Muslims to be the location from which Muhammad ascended to Jannah (paradise); there is no mention of Jerusalem in the Koran, however.
This widely accepted Islamic belief raises the religious and spiritual importance to them of the Dome of the Rock and the adjacent al-Aqsa Mosque. Muslims are sensitive to and mindful of the circumstance that two mosques along with the rest of East Jerusalem are claimed and illegally occupied by the state of Israel.
Specific impulse
Specific impulse (often shortened to "I") is a way to describe how well a rocket performs. It is also used to describe how well a jet engine performs. It can be used to compare rockets of different sizes. It is a way to know how much force a given engine makes for each bit of fuel. To do this, one needs to know how much fuel is in the engine. A high specific impulse means that a rocket needs less fuel to perform as well. If the specific impulse is lower, it means that the rocket needs more fuel to perform as well.
Specific impulse is a useful value to compare rocket or jet engines. It is used much like "miles per gallon" or "litres per 100 kilometres" is used to compare cars. An engine with a higher specific impulse uses fuel better. This means that the same amount of fuel lets the rocket go faster after all fuel is depleted.
A rocket engine with a higher specific impulse doesn't mean it's 'more powerful'. That is, it will not make the rocket accelerate harder. In fact, the designs for engines with the highest specific impulse, like ion engines, are the 'weakest' of all types of engines. They accelerate the rocket slowly but steadily over a long period of time using only a tiny amount of fuel. In a race between two rockets with the same amount of fuel and two different engines the one with the more powerful engine will take an early lead, but when it burns down all its fuel, the rocket with higher specific impulse will still have some fuel left and will continue to accelerate. Eventually it will overtake its counterpart and will win the race if the distance is big enough for it to use its long-term advantage.
There are two ways people find the number for specific impulse. To find the specific impulse, one divides the impulse by the amount of fuel. Impulse is a measurement of how much force a rocket motor makes and for how long. A motor that makes a low force for a long time can sometimes have a higher impulse than a motor that makes a high force for a short time. Impulse is measured in Newtons times seconds (N*s).
The amount of fuel used to find specific impulse can be measured in different ways. It is sometimes measured in mass and sometimes in weight. When the amount of fuel is measured in mass, the specific impulse is expressed as a speed. This is usually in meters per second. When specific impulse is measured as a speed, it has another name. It is also called the "effective exhaust velocity". The other way to measure the amount of fuel is weight. If weight is used, the specific impulse is in units of time, usually in seconds. These two ways are both common. They both compare the performance of engines.
When the specific impulse is higher, less fuel is needed to make the rocket perform at a certain level. So, a fuel is more efficient if the specific impulse is higher.
Be careful not to confuse thrust and specific impulse. Thrust is only the force made by a rocket at one point in time. Specific impulse is a measure of the force based on how much fuel there is.
When people find specific impulse, the only fuel counted is in the rocket before it gets fired. This includes the fuel and the oxidizer (the part of the fuel that helps the fuel burn). The oxidizer is sometimes oxygen, or often something else (see Rocket engine#Liquids, solids and hybrids).
Jet (airplane) engines use fuel better than rocket engines. This is because the gases do not escape as fast. Because they do not escape as fast, the exhaust does not carry away as much energy. This means that the jet engine uses a lot less energy to push the jet. It is also because the air that goes through the engine as the jet flies through the air helps the fuel to burn faster.
Specific impulse is also used to describe how well model rocket motors work. In the table below are some of Estes' claimed values for specific impulses for several of their rocket motors: Estes Industries is a large, well known American seller of model rockets and rocket parts. The specific impulse for model rocket motors is much lower than for many other rocket motors because the black powder is used as a fuel. Black powder is used in model rocket motors because it costs less.
Here are some example numbers for larger rocket engines:
The most common way to measure specific impulse today uses seconds. This is used both in the SI (metric system) world as well as where English units are used. This way the units are identical everywhere. This means specific impulse can be used to compare engine performance in any country. Most companies that make rocket motors or jet engines use seconds to advertise their product’s performance.
The other common way to measure specific impulse is in meters per second (m/s), which is also called effective exhaust velocity. For many engines the effective exhaust velocity is different from the speed that the gases actually come out of the nozzle.
Aromatic hydrocarbon
An aromatic hydrocarbon, or arene, is a hydrocarbon ring compound. It has alternating double and single bonds between carbon atoms forming rings. Many of the compounds have a sweet scent, hence the term 'aromatic'. The ring of six carbon atoms in aromatic compounds is known as a benzene ring, after the simplest possible hydrocarbon ring, benzene. Aromatic hydrocarbons can be "monocyclic" (MAH) or "polycyclic" (PAH).
Some non-benzene-based compounds called heteroarenes, which follow Hückel's rule, are also aromatic compounds. In these compounds, at least one carbon atom is replaced by one of oxygen, nitrogen, or sulfur.
Benzene, CH, is the simplest aromatic hydrocarbon and was recognized as the first aromatic hydrocarbon, with the nature of its bonding first being recognized by Kekulé in the 19th century.
Each carbon atom in the hexagonal cycle has four electrons to share. One goes to the hydrogen atom, and one each to the two neighboring carbons. This leaves one to share with one of its two neighboring carbon atoms, which is why the benzene molecule is drawn with alternating single and double bonds around the hexagon.
The structure is also illustrated as a circle around the inside of the ring to show six electrons floating around in delocalized molecular orbitals the size of the ring itself. This also represents the equivalent nature of the six carbon-carbon bonds each equivalent to ~1.5. The electrons are visualized as floating above and below the ring with the electromagnetic fields they generate acting to keep the ring flat.
General properties:
The circle symbol for aromaticity was introduced by Sir Robert Robinson and his student James Armit in 1925 and popularized starting in 1959 by the Morrison & Boyd textbook on organic chemistry. The proper use of the symbol is debated; it is used to describe any cyclic pi system in some publications, or only those pi systems that obey Hückel's rule on others.
A reaction that forms an arene compound from an unsaturated or partially unsaturated cyclic precursor is simply called an aromatization. Many laboratory methods exist for the organic synthesis of arenes from non-arene precursors.
Aromatic compounds play key roles in the biochemistry of all living things. The four aromatic amino acids histidine, phenylalanine, tryptophan, and tyrosine each serve as one of the 20 basic building blocks of proteins. Further, all 5 nucleotides (adenine, thymine, cytosine, guanine, and uracil) that make up the sequence of the genetic code in DNA and RNA are aromatic purines or pyrimidines. As well as that, the molecule heme contains an aromatic system with 22 π electrons. Chlorophyll also has a similar aromatic system.
Aromatic compounds are important in industry. Key aromatic hydrocarbons of commercial interest are benzene, toluene, "ortho"-xylene and "para"-xylene. About 35 million tonnes are produced worldwide every year. They are extracted from complex mixtures obtained by the refining of oil or by distillation of coal tar. They are used to produce a range of important chemicals and polymers, including styrene, phenol, aniline, polyester and nylon.
Almost all aromatic compounds are compounds of carbon, but they need not be hydrocarbons.
In heterocyclic aromatics one or more of the atoms in the aromatic ring is of an element other than carbon. Examples include pyridine, pyrazine, imidazole, pyrazole, oxazole, and thiophene.
Polycyclic aromatic hydrocarbons are molecules with two or more simple aromatic rings fused together by sharing two neighboring carbon atoms. Examples are naphthalene, anthracene and phenanthrene.
Many chemical compounds are aromatic rings with other things attached. Examples include trinitrotoluene (TNT), acetylsalicylic acid (aspirin), paracetamol, and the nucleotides of DNA.
Erich Probst
Erich Probst (5 December 1927 – 16 March 1988) was an Austrian footballer.He played as striker for different teams in Vienna and also abroad.
He started with Admira Wien being only 17 years old. After a year with Vienna he signed with SK Rapid Wien. In this time he won the Austrian Championship four times. In his first season with Rapid he scored 28 goals in 23 matches. Although he was always a top scorer he never shot the highest number of goals in the league.
After his time with Rapid he went to Wuppertaler SV in Germany. After the relegation of Wuppertal he went on to Switzerland playing for FC Zürich. In winter 1959 he came back to Austria to SV Austria Salzburg. The club paid 90 000 Austrian schillings, which was the highest till this time. He shot 15 goals and the team could stay in the top league. During his time with Salzburg he played his last match in the national football team. He was the first player of SV Austria Salzburg who ever played for the team.
In the 1960/61 season he was coach of SV Austria but not successful. So he went on to play as striker again. His last clubs were the SAK 1914 in Salzburg and First Vienna FC in Vienna. At all he scored 150 goals in Austrias top league.
He played 19 times for the Austrian national football team and scored 17 goals. His first match was on 27 May 1951 (4:0 versus Scotland) In the qualification match for the FIFA World Cup 1954 versus Portugal he scored 5 goals for the 9:1 win. He was member of the 1954 FIFA World Cup squad which reached the third place. During the tournament he scored six goals and was together with Max Morlock of Germany and Josef Hügi of Switzerland second in the scorer list. During his time abroad he was not player of the team. But in 1960 he played his last match versus France (2:4) where he also scored his last goal for the team. So he was the first national football team player coming from SV Austria Salzburg.
Mac Miller
Malcolm James McCormick (January 19, 1992 – September 7, 2018), known professionally as Mac Miller, was an American rapper, singer, songwriter, and record producer. He was also a noted under the pseudonym Larry Fisherman.
In early 2010, Miller signed a record deal with Pittsburgh-based indie record label Rostrum Records. He subsequently began recording his debut studio album "Blue Slide Park", and released it on November 8, 2011. The album went on to debut at number one on the U.S. "Billboard" 200 chart, making it the first independently distributed debut album to top the chart since Tha Dogg Pound's 1995 album, "Dogg Food".
In early 2013, Miller launched REMember Music, his own record label imprint, named after a friend who died. Miller's second album, "Watching Movies with the Sound Off", was released on June 18, 2013. In January 2014, Miller announced he was no longer signed to Rostrum Records. In October 2014, it was reported Miller signed a record deal for him and his label REMember, with Warner Bros. Records.
Miller died of an accidental drug overdose on September 7, 2018 at the age of 26. The cause of death was because Miller had mixed Fentanyl with Cocaine.
Crossfade (band)
Crossfade is an American rock band from Columbia, South Carolina. Crossfade has three members in the band; the current band members are Ed Sloan, Les Hall, and Mitch James. Their best known song is "Cold" which was released on May 25, 2004 and reached #2 on Billboard's Alternative Songs chart and #3 on the Billboard Mainstream Rock Tracks.
So far as of 2011, Crossfade has released 3 studio albums:
Yabasic (Yet Another BASIC) is an interpreter program for a version of BASIC. BASIC is a programming language. BASIC was designed by John George Kemeny and Thomas Kurtz, in 1964. However, Yabasic was born in 1995, 32 years later. Pedro Sá and Thomas Larsen are now developing version 3 of Yabasic. Yasbic is very compact at about 250 kilobytes total length.
To write something on the monitor, like Hello World, type print then <nowiki>"YOUR TEXT HERE".</nowiki>
Study this bit of code:
The result of this code is:
An audible beep is generated
The program waits for 1 second before going onto the next instruction
It then goes back to the start of the program creating an infinite loop.
This programming language can also be used to create rather complex programs such as one that calculates prime numbers
The "input" command asks the user to input a value which in this case is number that tells the program what number to stop finding prime numbers at.
commands create a loop that can be repeated infinitely.
commands hold instructions as to what the program is to do while in the loop.
commands tell the program to look for something and if the thing it is looking for is there then it reports back that it is there.
Shaun Marsh
Shaun Edward Marsh (born 9 July, 1983 in Narrogin, Western Australia) is an Australian cricketer. He is nicknamed 'Sos'. He is a left-handed batsman with a first-class batting average of 40.
On 8 September, 2011, Marsh made his Test debut for Australia in the 2nd Test against Sri Lanka at Pallekele in replace of the unavailable Ricky Ponting. Thus far in the Australian innings, Marsh has scored 87* batting with Michael Hussey in a 148 run partnership.
Isolobal principle
The isolobal principle (also known as isolobal analogy) is way to predict bonding properties of organometallic compounds. In organometallic chemistry, it relates the structure of organic ligands that can bind to inorganic molecular fragments. Roald Hoffmann described molecular fragments as isolobal "if the number, symmetry properties, approximate energy and shape of the frontier orbitals and the number of electrons in them are similar – not identical, but similar." One can predict the bonding and reactivity of a lesser-known pieces from that of a better-known pieces if the two molecular fragments have similar frontier orbitals, the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO). Isolobal compounds are analogs to isoelectronic compounds that share the same number of valence electrons and structure. A graphic representation of isolobal structures, with the isolobal pairs connected through a double-headed arrow with half an orbital below, is found in Figure 1.
For his work on the isolobal analogy, Hoffmann was awarded the Nobel Prize in Chemistry in 1981, which he shared with Kenichi Fukui. In his Nobel Prize lecture, Hoffmann stressed that the isolobal analogy is a useful, yet simple, model. It does fail in certain instances.
Alcibiades, son of Clinias, "c." 450–404 BC), was a prominent Athenian statesman, orator, and general. He was the last famous member of his mother's aristocratic family, which fell from power after the Peloponnesian War. He played a major role later in that conflict as a strategic advisor, military commander, and politician.
During the course of the Peloponnesian War, Alcibiades changed sides on several occasions. In his native Athens in the early 410s BC, he advocated an aggressive foreign policy, and spoke in favor of an invasion of Sicily. He fled to Sparta after his political enemies brought charges of sacrilege against him.
In Sparta, he served as a strategic adviser, proposing or supervising several major campaigns against Athens. In Sparta too, however, Alcibiades soon made powerful enemies and was forced to defect to Persia. There he served as an adviser to the satrap Tissaphernes until his Athenian political allies brought about his recall. He then served as an Athenian general for several years, but his enemies eventually succeeded in exiling him a second time.
The Sicilian Expedition to Magna Graecia was Alcibiades' idea but his enemies prevented him from commanding. His rival Nicias took command, and the expedition failed disastrously. In the years that he served Sparta, Alcibiades played a role in Athens' undoing; the capture of Decelea and the revolts of several critical Athenian subjects occurred either at his suggestion or under his supervision.