Boron is a chemical element with the symbol B and atomic number 5. Produced by cosmic ray spallation and supernovae and not by stellar nucleosynthesis, it is a low-abundance element in the Solar system and in the Earth's crust. Boron is concentrated on Earth by the water-solubility of its more common occurring compounds, the borate minerals; these are mined industrially as evaporites, such as kernite. The largest known boron deposits are in the largest producer of boron minerals. Elemental boron is a metalloid, found in small amounts in meteoroids but chemically uncombined boron is not otherwise found on Earth. Industrially pure boron is produced with difficulty because of refractory contamination by carbon or other elements. Several allotropes of boron exist: amorphous boron is a brown powder; the primary use of elemental boron is as boron filaments with applications similar to carbon fibers in some high-strength materials. Boron is used in chemical compounds. About half of all boron consumed globally is an additive in fiberglass for insulation and structural materials.
The next leading use is in polymers and ceramics in high-strength, lightweight structural and refractory materials. Borosilicate glass is desired for its greater strength and thermal shock resistance than ordinary soda lime glass. Boron as sodium perborate is used as a bleach. A small amount of boron is used as a dopant in semiconductors, reagent intermediates in the synthesis of organic fine chemicals. A few boron-containing organic pharmaceuticals are in study. Natural boron is composed of two stable isotopes, one of which has a number of uses as a neutron-capturing agent. In biology, borates have low toxicity in mammals, but are more toxic to arthropods and are used as insecticides. Boric acid is mildly antimicrobial, several natural boron-containing organic antibiotics are known. Boron is an essential plant nutrient and boron compounds such as borax and boric acid are used as fertilizers in agriculture, although it's only required in small amounts, with excess being toxic. Boron compounds play a strengthening role in the cell walls of all plants.
There is no consensus on whether boron is an essential nutrient for mammals, including humans, although there is some evidence it supports bone health. The word boron was coined from borax, the mineral from which it was isolated, by analogy with carbon, which boron resembles chemically. Borax, its mineral form known as tincal, glazes were used in China from AD 300, some crude borax reached the West, where the Perso-Arab alchemist Jābir ibn Hayyān mentioned it in AD 700. Marco Polo brought some glazes back to Italy in the 13th century. Agricola, around 1600, reports the use of borax as a flux in metallurgy. In 1777, boric acid was recognized in the hot springs near Florence and became known as sal sedativum, with medical uses; the rare mineral is called sassolite, found at Sasso, Italy. Sasso was the main source of European borax from 1827 to 1872. Boron compounds were rarely used until the late 1800s when Francis Marion Smith's Pacific Coast Borax Company first popularized and produced them in volume at low cost.
Boron was not recognized as an element until it was isolated by Sir Humphry Davy and by Joseph Louis Gay-Lussac and Louis Jacques Thénard. In 1808 Davy observed that electric current sent through a solution of borates produced a brown precipitate on one of the electrodes. In his subsequent experiments, he used potassium to reduce boric acid instead of electrolysis, he named the element boracium. Gay-Lussac and Thénard used iron to reduce boric acid at high temperatures. By oxidizing boron with air, they showed. Jöns Jacob Berzelius identified boron as an element in 1824. Pure boron was arguably first produced by the American chemist Ezekiel Weintraub in 1909; the earliest routes to elemental boron involved the reduction of boric oxide with metals such as magnesium or aluminium. However, the product is always contaminated with borides of those metals. Pure boron can be prepared by reducing volatile boron halides with hydrogen at high temperatures. Ultrapure boron for use in the semiconductor industry is produced by the decomposition of diborane at high temperatures and further purified by the zone melting or Czochralski processes.
The production of boron compounds does not involve the formation of elemental boron, but exploits the convenient availability of borates. Boron is similar to carbon in its capability to form stable covalently bonded molecular networks. Nominally disordered boron contains regular boron icosahedra which are, bonded randomly to each other without long-range order. Crystalline boron is a hard, black material with a melting point of above 2000 °C, it forms four major polymorphs: β-rhombohedral, γ and β-tetragonal. Most of the phases are based on B12 icosahedra, but the γ-phase can be described as a rocksalt-type arrangement of the icosahedra and B2 atomic pairs, it can be produced by compressing other boron phases to 12–20 GPa and heating to 1500–1800 °C. The T phase is produced at similar pressures, but higher temperatures of 1800–2200 °C; as to the α and β phases, they might both coexist at ambient conditions with the β phase being more sta
Jerusalem Metropolitan Park is a 43-kilometer park being developed around the city of Jerusalem, Israel. The plan for the park includes hiking trails, picnic areas and cafes; the Jewish National Fund is upgrading natural and historical sites to make them accessible to the general public. The park will extend over 1,500 hectares of land, incorporating the Arazim valley near Mevasseret Zion, Motza valley to the west, Refaim valley in the south. In 2011, a 5-kilometer bike trail was inaugurated in Emek Ha'arazim, part of a larger trail that will ring the city, it begins near the remains of a Crusader fortress and ends near Motza, off the main Jerusalem-Tel Aviv highway. In 1906, Zionist pioneers purchased land in the Arazim valley. Dov Klinger, a chemist, planned to build an olive oil soap factory there but his efforts were unsuccessful. In 1920, the site was resettled by eight families. All were murdered except for two children. One was nine-year old Mordechai Maklef, who became the third Chief of Staff of the Israeli Defense Forces.
A memorial to the 9/11 attack on the Twin Towers is located on a hill in the park. Sculptor Eliezer Weishoff designed a bronze US flag in the shape of a memorial flame with a piece of aluminum from the wreckage incorporated in the base; the names of the 2,779 victims are inscribed on the walls around the plaza
Massachusetts liberal is a phrase in American politics, used as a derogatory political epithet by Republicans against Democrats who are from the Commonwealth of Massachusetts. It was most used in the 1988 presidential race by Vice President George H. W. Bush against Governor Michael Dukakis, again in the 2004 race by then-President George W. Bush against Senator John Kerry; the Democratic candidates lost both races. In the Republican 2012 presidential primary election Newt Gingrich used the phrase "Massachusetts moderate," based on the liberal pejorative against Mitt Romney, the former Governor of Massachusetts, whose main residence was a mansion in the state. Romney lost the presidential election; the idea behind the usage of the phrase is that the state of Massachusetts is "against the mainstream" in comparison to other states. Jane Elmes-Crahall, a professor who studies political rhetoric, has said, in swing and red states, "It still signals the antithesis of their social and economic values."
Hence, it is believed, people in these states will not vote for someone they believe to be a "Massachusetts liberal."There are several specific ideologies that are implied in the phrase: Being "soft on crime". Willie Horton was a convicted murderer. Alleged support for higher taxes. Among some, the state has a reputation for high taxes, some Republicans refer to it as "Taxachusetts." Support for anti-war ideas. This particular inference comes from the 1972 Presidential race, when Massachusetts was the only state where antiwar Senator George McGovern defeated President Richard Nixon. In more recent times, such as the 2004 presidential race, the term is meant to point to the state's legalization of same-sex marriage, it was the first state. Liberal elite Politics of Massachusetts San Francisco values