Potassium is a chemical element with symbol K and atomic number 19. It was first isolated from the ashes of plants, from which its name derives. In the periodic table, potassium is one of the alkali metals. All of the alkali metals have a single valence electron in the outer electron shell, removed to create an ion with a positive charge – a cation, which combines with anions to form salts. Potassium in nature occurs only in ionic salts. Elemental potassium is a soft silvery-white alkali metal that oxidizes in air and reacts vigorously with water, generating sufficient heat to ignite hydrogen emitted in the reaction, burning with a lilac-colored flame, it is found dissolved in sea water, is part of many minerals. Potassium is chemically similar to sodium, the previous element in group 1 of the periodic table, they have a similar first ionization energy, which allows for each atom to give up its sole outer electron. That they are different elements that combine with the same anions to make similar salts was suspected in 1702, was proven in 1807 using electrolysis.
Occurring potassium is composed of three isotopes, of which 40K is radioactive. Traces of 40K are found in all potassium, it is the most common radioisotope in the human body. Potassium ions are vital for the functioning of all living cells; the transfer of potassium ions across nerve cell membranes is necessary for normal nerve transmission. Fresh fruits and vegetables are good dietary sources of potassium; the body responds to the influx of dietary potassium, which raises serum potassium levels, with a shift of potassium from outside to inside cells and an increase in potassium excretion by the kidneys. Most industrial applications of potassium exploit the high solubility in water of potassium compounds, such as potassium soaps. Heavy crop production depletes the soil of potassium, this can be remedied with agricultural fertilizers containing potassium, accounting for 95% of global potassium chemical production; the English name for the element potassium comes from the word "potash", which refers to an early method of extracting various potassium salts: placing in a pot the ash of burnt wood or tree leaves, adding water and evaporating the solution.
When Humphry Davy first isolated the pure element using electrolysis in 1807, he named it potassium, which he derived from the word potash. The symbol "K" stems from kali, itself from the root word alkali, which in turn comes from Arabic: القَلْيَه al-qalyah "plant ashes". In 1797, the German chemist Martin Klaproth discovered "potash" in the minerals leucite and lepidolite, realized that "potash" was not a product of plant growth but contained a new element, which he proposed to call kali. In 1807, Humphry Davy produced the element via electrolysis: in 1809, Ludwig Wilhelm Gilbert proposed the name Kalium for Davy's "potassium". In 1814, the Swedish chemist Berzelius advocated the name kalium for potassium, with the chemical symbol "K"; the English and French speaking countries adopted Davy and Gay-Lussac/Thénard's name Potassium, while the Germanic countries adopted Gilbert/Klaproth's name Kalium. The "Gold Book" of the International Union of Physical and Applied Chemistry has designated the official chemical symbol as K.
Potassium is the second least dense metal after lithium. It is a soft solid with a low melting point, can be cut with a knife. Freshly cut potassium is silvery in appearance, but it begins to tarnish toward gray on exposure to air. In a flame test and its compounds emit a lilac color with a peak emission wavelength of 766.5 nanometers. Neutral potassium atoms have 19 electrons, one more than the stable configuration of the noble gas argon; because of this and its low first ionization energy of 418.8 kJ/mol, the potassium atom is much more to lose the last electron and acquire a positive charge than to gain one and acquire a negative charge. This process requires so little energy that potassium is oxidized by atmospheric oxygen. In contrast, the second ionization energy is high, because removal of two electrons breaks the stable noble gas electronic configuration. Potassium therefore does not form compounds with the oxidation state of higher. Potassium is an active metal that reacts violently with oxygen in water and air.
With oxygen it forms potassium peroxide, with water potassium forms potassium hydroxide. The reaction of potassium with water is dangerous because of its violent exothermic character and the production of hydrogen gas. Hydrogen reacts again with atmospheric oxygen, producing water, which reacts with the remaining potassium; this reaction requires only traces of water. Because of the sensitivity of potassium to water and air, reactions with other elements are possible only in an inert atmosphere such as argon gas using air-free techniques. Potassium does not react with most hydrocarbons such as mineral kerosene, it dissolves in liquid ammonia, up to 480 g per 1000 g of ammonia at 0 °C. Depending on the concentration, the ammonia solutions are blue to yellow, their electrical conductivity is similar to that of liquid metals. In a pure solution, potassium reacts with ammonia to form KNH2, but this reaction is accelerated by minute amounts of transition metal s
Stein am Rhein
Stein am Rhein is a historic town and a municipality in the canton of Schaffhausen in Switzerland. The town's medieval centre retains the ancient street plan; the site of the city wall, the city gates are preserved, though the former city wall now consists of houses. The medieval part of the town has been pedestrianised and many of the medieval buildings are painted with frescoes; the official language of Stein is German, but the main spoken language is the local variant of the Alemannic Swiss German dialect. In or around 1007 Emperor Henry II moved St George's Abbey from its former location on the Hohentwiel in Singen to Stein am Rhein, at that time little more than a small fishing village on the Rhine; this was in order to strengthen his presence at this strategic point where major road and river routes intersected. He gave the abbots extensive rights over Stein and its trade so that they could develop it commercially. In this they were successful, Stein am Rhein became a prosperous town which in the 15th century was granted reichsfrei status.
The Imperial abbey prospered and in the 15th century rebuilt its premises, which remain as a significant example of late Gothic architecture in the region. Under the Reformation, the abbey was secularised and its assets taken over by Zürich. Abbot von Winkelsheim negotiated a settlement with the Zürich authorities, although control of the abbey was handed over to them, he and the remaining monks would be allowed to remain on the premises until their deaths. However, Zürich suspected the abbot of collusion with the Habsburgs and locked him up in his new rooms, he was able to escape to Radolfzell, but died shortly after, in 1526. Stein am Rhein was the birthplace of Johann Heynlin, who introduced the first printing press into France. On February 22, 1945, the town was bombed by the United States Air Force; the blazon of the municipal coat of arms is Gules St. George armoured Azure mulleted and haloed Or riding a Horse Argent to sinister holding in sinister an escutcheon Argent cross Gules and in dexter a lance Or killing a Dragon Vert.
This is a reference to the monastery of St. George in the town; the coat of arms bears similarity to Coat of arms of Moscow. Stein am Rhein has an area, as of 2018, of 6.05 km2. Of this area, 29.9 % is used for agricultural purposes. Of the rest of the land, 22% is settled and the remainder is non-productive. Stein am Rhein has a population of 3,376. In 2008 a total of 20.6% of the population were foreign nationals. Of the foreign population, 38.6% are from Germany, 6.9% are from Italy, 3.2% are from Croatia, 12.8% are from Serbia, 10.8% are from Macedonia, 1.8% are from Turkey, 25.8% are from other countries. Most of the population speaks German, with Serbo-Croatian being second most common and Albanian being third.as of 2008 Children and teenagers make up 19.2% of the population, while adults make up 59.2% and seniors make up 21.5%. In the 2007 federal election the most popular party was the Swiss People's Party which received 42% of the vote; the next two most popular parties were the Social Democratic Party of Switzerland, the Free Democratic Party of Switzerland.
About 75% of the population have completed either non-mandatory upper secondary education or additional higher education. As of 2007, 1.65% of the population attend kindergarten or another pre-school, 5.66% attend a Primary School, 3.08% attend a lower level Secondary School, 2.13% attend a higher level Secondary School. As of 2000, 25.1% of the population belonged to the Roman Catholic Church and 50.6% belonged to the Swiss Reformed Church. The historical population is given in the following table: Stein am Rhein has an unemployment rate of 1.74%. As of 2005, there were 61 people employed in the primary economic sector and about 14 businesses involved in this sector. 553 people are employed in the secondary sector and there are 45 businesses in this sector. 856 people are employed with 172 businesses in this sector. As of 2008 the mid year average unemployment rate was 2.1%. There were 217 non-agrarian businesses in the municipality and 38.6% of the population was involved in the secondary sector of the economy while 61.4% were involved in the third.
At the same time, 71.1% of the working population was employed full-time, 28.9% was employed part-time. There were 1552 residents of the municipality who were employed in some capacity, of which females made up 44.1% of the workforce. As of 2000 there were 644 residents who worked in the municipality, while 714 residents worked outside Stein am Rhein and 625 people commuted into the municipality for work; as of 2008, there are 16 restaurants, 10 hotels with 435 beds. The hospitality industry in Stein am Rhein employs 105 people. Stein am Rhein railway station is situated on the opposite bank of the Rhine to the historic centre of the town, a walk of some 500 m, it is served by services to Schaffhausen, St. Gallen and Winterthur. Stein am Rhein received the first Wakker Prize for the preservation of its architectural heritage in 1972; the award noted that Stein am Rhein was nearly unique in Switzerland and rare in all of Europe for the number of notable buildings in a compact space. It noted the excellent care with which the city was preserved.
Mathias Gnädinger Stein am Rhein is home to several b
Oslo is the capital and most populous city of Norway. It constitutes both a municipality. Founded in the year 1040 as Ánslo, established as a kaupstad or trading place in 1048 by Harald Hardrada, the city was elevated to a bishopric in 1070 and a capital under Haakon V of Norway around 1300. Personal unions with Denmark from 1397 to 1523 and again from 1536 to 1814 reduced its influence, with Sweden from 1814 to 1905 it functioned as a co-official capital. After being destroyed by a fire in 1624, during the reign of King Christian IV, a new city was built closer to Akershus Fortress and named Christiania in the king's honour, it was established as a municipality on 1 January 1838. The city's name was spelled Kristiania between 1897 by state and municipal authorities. In 1925 the city was renamed Oslo. Oslo is the governmental centre of Norway; the city is a hub of Norwegian trade, banking and shipping. It is maritime trade in Europe; the city is home to many companies within the maritime sector, some of which are among the world's largest shipping companies and maritime insurance brokers.
Oslo is a pilot city of the Council of Europe and the European Commission intercultural cities programme. Oslo is considered a global city and was ranked "Beta World City" in studies carried out by the Globalization and World Cities Study Group and Network in 2008, it was ranked number one in terms of quality of life among European large cities in the European Cities of the Future 2012 report by fDi magazine. A survey conducted by ECA International in 2011 placed Oslo as the second most expensive city in the world for living expenses after Tokyo. In 2013 Oslo tied with the Australian city of Melbourne as the fourth most expensive city in the world, according to the Economist Intelligence Unit's Worldwide Cost of Living study; as of 1 July 2017, the municipality of Oslo had a population of 672,061, while the population of the city's urban area of 3 December 2018 was 1,000,467. The metropolitan area had an estimated population of 1.71 million. The population was increasing at record rates during the early 2000s, making it the fastest growing major city in Europe at the time.
This growth stems for the most part from international immigration and related high birth rates, but from intra-national migration. The immigrant population in the city is growing somewhat faster than the Norwegian population, in the city proper this is now more than 25% of the total population if immigrant parents are included; as of 1 January 2016, the municipality of Oslo had a population of 658,390. The urban area extends beyond the boundaries of the municipality into the surrounding county of Akershus; the city centre is situated at the end of the Oslofjord, from which point the city sprawls out in three distinct "corridors"—inland north-eastwards, southwards along both sides of the fjord—which gives the urbanized area a shape reminiscent of an upside-down reclining "Y". To the north and east, wide forested hills rise above the city giving the location the shape of a giant amphitheatre; the urban municipality of Oslo and county of Oslo are two parts of the same entity, making Oslo the only city in Norway where two administrative levels are integrated.
Of Oslo's total area, 130 km2 is built-up and 7 km2. The open areas within the built-up zone amount to 22 km2; the city of Oslo was established as a municipality on 3 January 1838. It was separated from the county of Akershus to become a county of its own in 1842; the rural municipality of Aker was merged with Oslo on 1 January 1948. Furthermore, Oslo shares several important functions with Akershus county; as defined in January 2004 by the city council ^ The definition has since been revised in the 2015 census. After being destroyed by a fire in 1624, during the reign of King Christian IV, a new city was built closer to Akershus Fortress and named Christiania in the king's honour; the old site east of the Aker river was not abandoned however and the village of Oslo remained as a suburb outside the city gates. The suburb called Oslo was included in the city proper. In 1925 the name of the suburb was transferred to the whole city, while the suburb was renamed "Gamlebyen" to avoid confusion; the Old Town is an area within the administrative district Gamle Oslo.
The previous names are reflected in street names like Oslo Oslo hospital. The origin of the name Oslo has been the subject of much debate, it is derived from Old Norse and was — in all probability — the name of a large farm at Bjørvika, but the meaning of that name is disputed. Modern linguists interpret the original Óslo, Áslo or Ánslo as either "Meadow at the Foot of a Hill" or "Meadow Consecrated to the Gods", with both considered likely. Erroneously, it was once assumed that "Oslo" meant "the mouth of the Lo river", a supposed previous name for the river Alna. However, not only has no evidence been found of a river "Lo" predating the work where Peder Claussøn Friis first proposed this etymology, but the name is ungrammatical in Norwegian: the correct form would have been Loaros; the name Lo is now believed to be a back-formation arrived at by Friis in support of his etymology
Concrete Portland cement concrete, is a composite material composed of fine and coarse aggregate bonded together with a fluid cement that hardens over time—most a lime-based cement binder, such as Portland cement, but sometimes with other hydraulic cements, such as a calcium aluminate cement. It is distinguished from other, non-cementitious types of concrete all binding some form of aggregate together, including asphalt concrete with a bitumen binder, used for road surfaces, polymer concretes that use polymers as a binder; when aggregate is mixed together with dry Portland cement and water, the mixture forms a fluid slurry, poured and molded into shape. The cement reacts chemically with the water and other ingredients to form a hard matrix that binds the materials together into a durable stone-like material that has many uses. Additives are included in the mixture to improve the physical properties of the wet mix or the finished material. Most concrete is poured with reinforcing materials embedded to provide tensile strength, yielding reinforced concrete.
Famous concrete structures include the Panama Canal and the Roman Pantheon. The earliest large-scale users of concrete technology were the ancient Romans, concrete was used in the Roman Empire; the Colosseum in Rome was built of concrete, the concrete dome of the Pantheon is the world's largest unreinforced concrete dome. Today, large concrete structures are made with reinforced concrete. After the Roman Empire collapsed, use of concrete became rare until the technology was redeveloped in the mid-18th century. Worldwide, concrete has overtaken steel in tonnage of material used; the word concrete comes from the Latin word "concretus", the perfect passive participle of "concrescere", from "con-" and "crescere". Small-scale production of concrete-like materials was pioneered by the Nabatean traders who occupied and controlled a series of oases and developed a small empire in the regions of southern Syria and northern Jordan from the 4th century BC, they discovered the advantages of hydraulic lime, with some self-cementing properties, by 700 BC.
They built kilns to supply mortar for the construction of rubble-wall houses, concrete floors, underground waterproof cisterns. They kept the cisterns secret; some of these structures survive to this day. In the Ancient Egyptian and Roman eras, builders discovered that adding volcanic ash to the mix allowed it to set underwater. German archaeologist Heinrich Schliemann found concrete floors, which were made of lime and pebbles, in the royal palace of Tiryns, which dates to 1400–1200 BC. Lime mortars were used in Greece and Cyprus in 800 BC; the Assyrian Jerwan Aqueduct made use of waterproof concrete. Concrete was used for construction in many ancient structures; the Romans used concrete extensively from 300 BC to a span of more than seven hundred years. During the Roman Empire, Roman concrete was made from quicklime, pozzolana and an aggregate of pumice, its widespread use in many Roman structures, a key event in the history of architecture termed the Roman Architectural Revolution, freed Roman construction from the restrictions of stone and brick materials.
It enabled revolutionary new designs in terms of both structural dimension. Concrete, as the Romans knew it, was a revolutionary material. Laid in the shape of arches and domes, it hardened into a rigid mass, free from many of the internal thrusts and strains that troubled the builders of similar structures in stone or brick. Modern tests show that opus caementicium had as much compressive strength as modern Portland-cement concrete. However, due to the absence of reinforcement, its tensile strength was far lower than modern reinforced concrete, its mode of application was different: Modern structural concrete differs from Roman concrete in two important details. First, its mix consistency is fluid and homogeneous, allowing it to be poured into forms rather than requiring hand-layering together with the placement of aggregate, which, in Roman practice consisted of rubble. Second, integral reinforcing steel gives modern concrete assemblies great strength in tension, whereas Roman concrete could depend only upon the strength of the concrete bonding to resist tension.
The long-term durability of Roman concrete structures has been found to be due to its use of pyroclastic rock and ash, whereby crystallization of strätlingite and the coalescence of calcium–aluminum-silicate–hydrate cementing binder helped give the concrete a greater degree of fracture resistance in seismically active environments. Roman concrete is more resistant to erosion by seawater than modern concrete; the widespread use of concrete in many Roman structures ensured that many survive to the present day. The Baths of Caracalla in Rome are just one example. Many Roman aqueducts and bridges, such as the magnificent Pont du Gard in southern France, have masonry cladding on a concrete core, as does the dome of the Pantheon. After the Roman Empire, the use of burned lime and pozzolana was reduced until the technique was all but forgotten between 500 and the 14th century. From the 14th century to the mid-18th century, the use of cement returned; the Canal du Midi was built using concrete in 1670.
The greatest step forward in the modern use
Acid rain is a rain or any other form of precipitation, unusually acidic, meaning that it has elevated levels of hydrogen ions. It can have harmful effects on aquatic animals and infrastructure. Acid rain is caused by emissions of sulfur dioxide and nitrogen oxide, which react with the water molecules in the atmosphere to produce acids; some governments have made efforts since the 1970s to reduce the release of sulfur dioxide and nitrogen oxide into the atmosphere with positive results. Nitrogen oxides can be produced by lightning strikes, sulfur dioxide is produced by volcanic eruptions. Acid rain has been shown to have adverse impacts on forests and soils, killing insect and aquatic life-forms, causing paint to peel, corrosion of steel structures such as bridges, weathering of stone buildings and statues as well as having impacts on human health. "Acid rain" is a popular term referring to the deposition of a mixture from wet and dry acidic components. Distilled water, once carbon dioxide is removed, has a neutral pH of 7.
Liquids with a pH less than 7 are acidic, those with a pH greater than 7 are alkaline. "Clean" or unpolluted rain has an acidic pH, but no lower than 5.7, because carbon dioxide and water in the air react together to form carbonic acid, a weak acid according to the following reaction: H2O + CO2 ⇌ H2CO3 Carbonic acid can ionize in water forming low concentrations of carbonate and hydronium ions: H2O + H2CO3 ⇌ HCO3− + H3O+ Unpolluted rain can contain other chemicals which affect its pH. A common example is nitric acid produced by electric discharge in the atmosphere such as lightning. Acid deposition as an environmental issue would include additional acids other than H2CO3; the corrosive effect of polluted, acidic city air on limestone and marble was noted in the 17th century by John Evelyn, who remarked upon the poor condition of the Arundel marbles. Since the Industrial Revolution, emissions of sulfur dioxide and nitrogen oxides into the atmosphere have increased. In 1852, Robert Angus Smith was the first to show the relationship between acid rain and atmospheric pollution in Manchester, England.
In the late 1960s scientists began observing and studying the phenomenon. The term "acid rain" was coined in 1872 by Robert Angus Smith. Canadian Harold Harvey was among the first to research a "dead" lake. At first the main focus in research lay on local affects of acid rain. Waldemar Christofer Brøgger was the first to acknowledge long-distance transportation of pollutants crossing borders from the United Kingdom to Norway. Public awareness of acid rain in the US increased in the 1970s after The New York Times published reports from the Hubbard Brook Experimental Forest in New Hampshire of the harmful environmental effects that result from it. Occasional pH readings in rain and fog water of well below 2.4 have been reported in industrialized areas. Industrial acid rain is areas downwind from them; these areas all burn sulfur-containing coal to generate electricity. The problem of acid rain has not only increased with population and industrial growth, but has become more widespread; the use of tall smokestacks to reduce local pollution has contributed to the spread of acid rain by releasing gases into regional atmospheric circulation.
Deposition occurs a considerable distance downwind of the emissions, with mountainous regions tending to receive the greatest deposition. An example of this effect is the low pH of rain; the earliest report about acid rain in the United States was from the chemical evidence from Hubbard Brook Valley. In 1972, a group of scientists including Gene Likens discovered the rain, deposited at White Mountains of New Hampshire was acidic; the pH of the sample was measured to be 4.03 at Hubbard Brook. The Hubbard Brook Ecosystem Study followed up with a series of research that analyzed the environmental effects of acid rain. Acid rain that mixed with stream water at Hubbard Brook was neutralized by the alumina from soils; the result of this research indicates the chemical reaction between acid rain and aluminum leads to increasing rate of soil weathering. Experimental research was done to examine the effects of increased acidity in stream on ecological species. In 1980, a group of scientists modified the acidity of Norris Brook, New Hampshire, observed the change in species' behaviors.
There was a decrease in species diversity, an increase in community dominants, a decrease in the food web complexity. In 1980, the US Congress passed an Acid Deposition Act; this Act established an 18-year assessment and research program under the direction of the National Acidic Precipitation Assessment Program. NAPAP looked at the entire problem from a scientific perspective, it enlarged a network of monitoring sites to determine how acidic the precipitation was, to determine long-term trends, established a network for dry deposition. It looked at the effects of acid rain and funded research on the effects of acid precipitation on freshwater and terrestrial ecosystems, historical buildings and building materials, it funded extensive studies on atmospheric processes and potential control programs. From the start, policy advocates from all sides attempted to influence NAPAP activities to support their particular policy advocacy efforts, or to disparage those of their opponents. For the US Government's scientific enterprise, a significant impact of NAPAP were lessons learned in the assessment process and in environmental research management to a relatively
Potash is some of various mined and manufactured salts that contain potassium in water-soluble form. The name derives from pot ash, which refers to plant ashes soaked in water in a pot, the primary means of manufacturing the product before the industrial era; the word potassium is derived from potash. Potash is produced worldwide at amounts exceeding 90 million tonnes per year for use in manufacturing. Various types of fertilizer-potash constitute the single largest industrial use of the element potassium in the world. Potassium was first derived in 1807 by electrolysis of caustic potash. Potash refers to potassium compounds and potassium-bearing materials, the most common being potassium chloride; the term potash comes from the Middle Dutch word potaschen. The old method of making potassium carbonate was by collecting or producing wood ash, leaching the ashes and evaporating the resulting solution in large iron pots, leaving a white residue called pot ash. 10% by weight of common wood ash can be recovered as pot ash.
Potash became the term applied to occurring potassium salts and the commercial product derived from them. The following table lists a number of potassium compounds which use the word potash in their traditional names: All commercial potash deposits come from evaporite deposits and are buried deep below the earth's surface. Potash ores are rich in potassium chloride, sodium chloride and other salts and clays, are obtained by conventional shaft mining with the extracted ore ground into a powder. Other methods include dissolution evaporation methods from brines. In the evaporation method, hot water is injected into the potash, dissolved and pumped to the surface where it is concentrated by solar induced evaporation. Amine reagents are added to either the mined or evaporated solutions; the amine coats the KCl but not NaCl. Air bubbles cling to the amine + KCl and float it to the surface while the NaCl and clay sink to the bottom; the surface is skimmed for the amine + KCl, dried and packaged for use as a K rich fertilizer—KCl dissolves in water and is available for plant nutrition.
Potash deposits can be found all over the world. At present, deposits are being mined in Canada, China, Israel, Chile, the United States, Spain, the United Kingdom and Brazil, with the most significant deposits present in Saskatchewan, Canada. Excessive respiratory disease has been a concern for potash miners throughout history due to environmental hazards, such as radon and asbestos. Potash miners are liable to develop silicosis. Based on a study done between 1977 and 1987 cardiovascular disease among potash workers, the overall mortality rates were low, but a noticeable difference in above ground workers was documented. Potash has been used in bleaching textiles, making glass, making soap, since about AD 500. Potash was principally obtained by leaching the ashes of sea plants. Beginning in the 14th century potash was mined in Ethiopia. One of the world's largest deposits, 140 to 150 million tons, is located in the Tigray's Dallol area. Potash was one of the most important industrial chemicals.
It was refined from the ashes of broadleaved trees and produced in the forested areas of Europe and North America. The first U. S. patent of any kind was issued in 1790 to Samuel Hopkins for an improvement "in the making of Pot ash and Pearl ash by a new Apparatus and Process". Pearl ash was a purer quality made by calcination of potash in kiln. Potash pits were once used in England to produce potash, used in making soap for the preparation of wool for yarn production; as early as 1767, potash from wood ashes was exported from Canada, exports of potash and pearl ash reached 43,958 barrels in 1865. There were 519 asheries in operation in 1871; the industry declined in the late 19th century when large-scale production of potash from mineral salts was established in Germany. In 1943, potash was discovered in Canada, in the process of drilling for oil. Active exploration began in 1951. In 1958, the Potash Company of America became the first potash producer in Canada with the commissioning of an underground potash mine at Patience Lake.
The underground mine was flooded in 1987 and was reactivated for commercial production as a solution mine in 1989. In the late 18th and early 19th centuries, potash production provided settlers in North America a way to obtain badly needed cash and credit as they cleared wooded land for crops. To make full use of their land, settlers needed to dispose of excess wood; the easiest way to accomplish this was to burn any wood not needed for construction. Ashes from hardwood trees could be used to make lye, which could either be used to make soap or boiled down to produce valuable potash. Hardwood could generate ashes at the rate of 60 to 100 bushels per acre. In 1790, ashes could be sold for $3.25 to $6.25 per acre in rural New York State – nearly the same rate as hiring a laborer to clear the same area. Potash making became a major industry in British North America. Great Britain was always the most important market; the American potash industry followed the woodsman's ax across the country. After about 1820, New York replaced New England as the most important source.
Potash production was always
Masonry is the building of structures from individual units, which are laid in and bound together by mortar. The common materials of masonry construction are brick, building stone such as marble and limestone, cast stone, concrete block, glass block, adobe. Masonry is a durable form of construction. However, the materials used, the quality of the mortar and workmanship, the pattern in which the units are assembled can affect the durability of the overall masonry construction. A person who constructs masonry is called a bricklayer; these are both classified as construction trades. Masonry is used for walls and buildings. Brick and concrete block are the most common types of masonry in use in industrialized nations and may be either weight-bearing or a veneer. Concrete blocks those with hollow cores, offer various possibilities in masonry construction, they provide great compressive strength, are best suited to structures with light transverse loading when the cores remain unfilled. Filling some or all of the cores with concrete or concrete with steel reinforcement offers much greater tensile and lateral strength to structures.
The use of material such as bricks and stones can increase the thermal mass of a building. Masonry can protect the building from fire. Masonry walls are more resistant to projectiles, such as debris from tornadoes. Extreme weather, under certain circumstances, can cause degradation of masonry due to expansion and contractions forces associated with freeze-thaw cycles. Masonry tends to be heavy and must be built upon a strong foundation, such as reinforced concrete, to avoid settling and cracking. Other than concrete, masonry construction does not lend itself well to mechanization, requires more skilled labor than stick-framing. Masonry consists of loose components and has a low tolerance to oscillation as compared to other materials such as reinforced concrete, wood, or metals. Masonry has high compressive strength under vertical loads but has low tensile strength unless reinforced; the tensile strength of masonry walls can be increased by thickening the wall, or by building masonry piers at intervals.
Where practical, steel reinforcements such as windposts can be added. A masonry veneer wall consists of masonry units clay-based bricks, installed on one or both sides of a structurally independent wall constructed of wood or masonry. In this context the brick masonry is decorative, not structural; the brick veneer is connected to the structural wall by brick ties. There is an air gap between the brick veneer and the structural wall; as clay-based brick is not waterproof, the structural wall will have a water-resistant surface and weep holes can be left at the base of the brick veneer to drain moisture that accumulates inside the air gap. Concrete blocks and cultured stones, veneer adobe are sometimes used in a similar veneer fashion. Most insulated buildings that utilize concrete block, adobe, veneers or some combination thereof feature interior insulation in the form of fiberglass batts between wooden wall studs or in the form of rigid insulation boards covered with plaster or drywall. In most climates this insulation is much more effective on the exterior of the wall, allowing the building interior to take advantage of the aforementioned thermal mass of the masonry.
This technique does, require some sort of weather-resistant exterior surface over the insulation and is more expensive. The strength of a masonry wall is not dependent on the bond between the building material and the mortar; the blocks sometimes have grooves or other surface features added to enhance this interlocking, some dry set masonry structures forgo mortar altogether. Solid brickwork is made of two or more wythes of bricks with the units running horizontally bound together with bricks running transverse to the wall; each row of bricks is known as a course. The pattern of headers and stretchers employed gives rise to different'bonds' such as the common bond, the English bond, the Flemish bond. Bonds can differ in insulating ability. Vertically staggered bonds tend to be somewhat stronger and less prone to major cracking than a non-staggered bond; the wide selection of brick styles and types available in industrialized nations allow much variety in the appearance of the final product. In buildings built during the 1950s-1970s, a high degree of uniformity of brick and accuracy in masonry was typical.
In the period since this style was thought to be too sterile, so attempts were made to emulate older, rougher work. Some brick surfaces are made to look rustic by including burnt bricks, which have a darker color or an irregular shape. Others may use antique salvage bricks, or new bricks may be artificially aged by applying various surface treatments, such as tumbling; the attempts at rusticity of the late 20th century have been carried forward by masons specializing in a free, artistic style, where the courses are intentionally not straight, instead weaving to form more organic impressions. A crinkle-crankl