Radon is a chemical element with the symbol Rn and atomic number 86. It is a radioactive, odorless, tasteless noble gas, it occurs in minute quantities as an intermediate step in the normal radioactive decay chains through which thorium and uranium decay into lead and various other short-lived radioactive elements. Its most stable isotope, 222Rn, has a half-life of only 3.8 days, making radon one of the rarest elements since it decays away so quickly. However, since thorium and uranium are two of the most common radioactive elements on Earth, they have three isotopes with long half-lives, on the order of several billions of years, radon will be present on Earth long into the future in spite of its short half-life as it is continually being generated; the decay of radon produces many other short-lived nuclides known as radon daughters, ending at stable isotopes of lead. Unlike all the other intermediate elements in the aforementioned decay chains, radon is, under normal conditions and inhaled.
Radon gas is considered a health hazard. It is the single largest contributor to an individual's background radiation dose, but due to local differences in geology, the level of the radon-gas hazard differs from location to location. Despite its short lifetime, radon gas from natural sources, such as uranium-containing minerals, can accumulate in buildings due to its high density, in low areas such as basements and crawl spaces. Radon can occur in ground water – for example, in some spring waters and hot springs. Epidemiological studies have shown a clear link between breathing high concentrations of radon and incidence of lung cancer. Radon is a contaminant. According to the United States Environmental Protection Agency, radon is the second most frequent cause of lung cancer, after cigarette smoking, causing 21,000 lung cancer deaths per year in the United States. About 2,900 of these deaths occur among people. While radon is the second most frequent cause of lung cancer, it is the number one cause among non-smokers, according to EPA policy-oriented estimates.
Significant uncertainties exist for the health effects of low-dose exposures. Unlike the gaseous radon itself, radon daughters are solids and stick to surfaces, such as airborne dust particles, which can cause lung cancer if inhaled. Radon is a colorless and tasteless gas and therefore is not detectable by human senses alone. At standard temperature and pressure, radon forms a monatomic gas with a density of 9.73 kg/m3, about 8 times the density of the Earth's atmosphere at sea level, 1.217 kg/m3. Radon is the densest of the noble gases. Although colorless at standard temperature and pressure, when cooled below its freezing point of 202 K, radon emits a brilliant radioluminescence that turns from yellow to orange-red as the temperature lowers. Upon condensation, radon glows. Radon is sparingly more soluble than lighter noble gases. Radon is appreciably more soluble in organic liquids than in water. Radon is a member of the zero-valence elements that are called noble gases, is chemically not reactive.
However, the 3.8-day half-life of radon-222 makes it useful in physical sciences as a natural tracer. Because radon is a gas at standard conditions, unlike its decay-chain parents, it can be extracted from them for research, it is inert to most common chemical reactions, such as combustion, because the outer valence shell contains eight electrons. This produces a stable, minimum energy configuration in which the outer electrons are bound, its first ionization energy—the minimum energy required to extract one electron from it—is 1037 kJ/mol. In accordance with periodic trends, radon has a lower electronegativity than the element one period before it, is therefore more reactive. Early studies concluded that the stability of radon hydrate should be of the same order as that of the hydrates of chlorine or sulfur dioxide, higher than the stability of the hydrate of hydrogen sulfide; because of its cost and radioactivity, experimental chemical research is performed with radon, as a result there are few reported compounds of radon, all either fluorides or oxides.
Radon can be oxidized by powerful oxidizing agents such as fluorine. It decomposes back to its elements at a temperature of above 523 K, is reduced by water to radon gas and hydrogen fluoride: it may be reduced back to its elements by hydrogen gas, it has a low volatility and was thought to be RnF2. Because of the short half-life of radon and the radioactivity of its compounds, it has not been possible to study the compound in any detail. Theoretical studies on this molecule predict that it should have a Rn–F bond distance of 2.08 ångström, that the compound is thermodynamically more stable and less volatile than its lighter counterpart xenon difluoride. The octahedral molecule RnF6 was predicted to have an lower enthalpy of formation than the difluoride; the + ion is believed to form by the following reaction: Rn + 2 +− → +− + 2 O2 For this reason, antimony pentafluoride together with chlorine trifluoride and N2F2Sb2F11 have been considered for radon gas removal in uranium mines due to the formation of radon–fluorine compounds.
Radon compounds can be formed by the decay of radium in radium halides, a reaction, used to reduce the amount of radon that escapes from targets during irradiation. Additionally, salts of the + cation w
Disciples of the Sun is the fourth studio album by the Danish power metal band Pyramaze, released on May 22, 2015. This album features a different lineup than the band's previous records. Pyramaze recruited vocalist Terje Harøy to replace Matt Barlow and Urban Breed after their departures, producer Jacob Hansen replaced Michael Kammeyer on guitars while remaining the band's producer; the album's title track had a music video produced to promote a first for the band. Disciples of the Sun was well-received, was compared favorably to the band's previous efforts. Jacob Hansen − Guitars, Bass Morten Gade Sørensen − Drums Jonah Weingarten − Keyboards Toke Skjønnemand − Guitars Terje Harøy − Vocals Pyramaze homepage
The battle of Wytyczno took place on October 1, 1939 near the village of Wytyczno near Włodawa in Poland. It was a struggle between the Polish forces of the Border Defence Corps of Gen. Wilhelm Orlik-Rückemann and the Soviet Red Army during the invasion of Poland. After the battle of Szack on September 28, the Polish commander decided to cross the Bug River and continue the fight there. After a short rest, on September 30 the Poles had crossed the river. Although victorious in most of the fights against the Soviets, the Polish unit was reduced to 3,000 men and was lacking heavy equipment and ammunition. In addition, most of the soldiers of the Border Defence Corps had been forced to cross large parts of Poland, with the average unit crossing 500 kilometres in two weeks. After crossing the Włodawa-Trawniki road, shortly after 1 AM on October 1, the Polish unit was attacked by a tank unit of the Soviet 45th Rifle Division. Polish Bofors 37 mm guns opened fire at close range and the Soviet unit withdrew losing four T-26 tanks.
Soon after daybreak the Soviets returned, this time with the majority of 45th division's units. The Soviets, expecting the Polish unit to be routed and composed of officers, started a frontal assault on the village of Wytyczno. However, the Polish tabors crossed the road into the forest behind the village and placed artillery posts there, which enabled the defending Poles to hold their positions; the struggle for the village continued, with both sides suffering heavy losses. At 9AM the Polish 75 mm artillery had no more than 60 shells left and the howitzers had not more than 10 per barrel. To lessen the enemy pressure on the centre of the Polish units, Gen. Wilhelm Orlik-Rückemann ordered the Polesie Battalion to attack the left flank of the enemy. However, the soldiers were too tired to start the assault and most of them declined to follow the order. Commander of the Sarny Regiment, Col. Nikodem Sulik, reported that the Polish defences were getting weaker with every hour and with all probability the battle would end by dawn with a complete Polish defeat.
At 10.30 a war council was held and it was decided that the only option for his men to survive was to withdraw, divide the unit onto smaller detachments and try to break through to the units of Independent Operational Group Polesie fighting nearby. At noon the Polish units withdrew to the forests. Most of them joined the other Polish unit, while Gen. Orlik-Rückemann found his way to Great Britain through Lithuania and Sweden. Czesław Grzelak. Szack - Wytyczno 1939. Warsaw, Bellona. ISBN 83-11-09324-5. Karol Liszewski. Wojna polsko-sowiecka 1939. Warsaw, Neriton. P. 520. ISBN 83-86842-02-4. Jerzy Łojek. Agresja 17 września. Warsaw, Most. P. 71. Stanley S. Seidner. Marshal Edward Śmigły-Rydz Rydz and the Defense of Poland. New York. P. 287. Orlik-Rückemann when interviewed contended that as many as 25–27 Soviet tanks were destroyed by the end of the battle. Soviet personnel losses were at 300–350
Year 1055 was a common year starting on Sunday of the Julian calendar. January 11 – Emperor Constantine IX dies after a 12½-year reign at Constantinople, he is succeeded by Theodora, proclaimed by the imperial guard as empress of the Byzantine Empire. King Ferdinand I begins his campaign against al-Andalus, he conquers Seia from the Christian allies of the Muslim taifas. In a drive to consolidate his southern border in Portugal – Ferdinand re-populates the city of Zamora with some of his Cantabrian subjects. October 24 – Ælfgar, earl of Mercia, is outlawed by the witan. In revenge he builds allies himself with the Welsh king Gruffydd ap Llywelyn. After defeating Ralph the Timid, they attack Hereford and raid the church – taking everything of value leaving the building on fire; the rebels attack Leominster. Edward the Confessor gives Tostig Godwinson the important position as earl of Northumbria and the difficult mission of bringing the northern state under control. Winter – The Seljuk Turks led by Sultan Tughril capture Baghdad and enter the city in a Roman-styled truimph.
Al-Malik al-Rahim, the last Buyid emir in Iraq, is taken prisoner. Construction on the Liaodi Pagoda in Hebei is completed. King Andrew I establishes the Benedictine Tihany Abbey, its foundation charter is the earliest written record extant in the Hungarian language. April 13 – Pope Victor II succeeds Leo IX as the 153rd pope of the Catholic Church in Rome. August 16 – Malik-Shah I, sultan of the Seljuk Empire September 28 – Uicheon, Korean Buddhist monk Adelaide of Weimar-Orlamünde, German noblewoman Alger of Liège, French clergyman and priest Bertha of Holland, French queen consort Fujiwara no Akisue, Japanese nobleman Gilbert Crispin, Norman abbot and theologian Gruffudd ap Cynan, king of Gwynedd Hildebert, French hagiographer and theologian Ida of Austria, German duchess and crusader Judith of Lens, niece of William the Conqueror Machig Labdrön, Tibetan Buddhist teacher Minamoto no Shunrai, Japanese poet Terken Khatun, Seljuk empress Vigrahapala III, ruler of the Pala Empire January 10 – Bretislav I, duke of Bohemia January 11 – Constantine IX, Byzantine emperor April 10 – Conrad II, duke of Bavaria May 26 – Adalbert, margrave of Austria August 28 – Xing Zong, Chinese emperor November 13 – Welf III, duke of Carinthia December 5 – Conrad I, duke of Bavaria A Nong, Chinese shamaness and warrior Benedict I, Hungarian politician and archbishop Boniface IV Frederick, margrave of Tuscany Gruffydd ap Rhydderch, king of Deheubarth Mauger, archbishop of Rouen Nong Zhigao, Vietnamese chieftain of Nong Rinchen Zangpo, Tibetan Buddhist monk Siward, earl of Northumbria Theodore Aaronios, Byzantine governor Yan Shu, Chinese statesman and poet
Anita Margaret Frew is a Scottish businessperson and Chairman of Croda. Born in Scotland, she is the daughter of a Supermarine Spitfire pilot, youngest of three daughters. Frew was educated at an all-girls convent in Norwich, before graduating from University of Strathclyde, she earned a master of research in Philosophy from the University of London. On graduation she joined Royal Bank of Scotland, before moving to Scottish Provident where she served as Head of UK Investment. Frew became Director of Corporate Development at WPP plc, she progressed to become a non-executive director of various commercial organisations including WPP plc and Northumbrian Water as well as Non-Executive Chairman of Victrex and pro bono non-executive director roles in various artistic organisations, including the Donmar Warehouse and the Gate Theatre. She stood down as Non-Executive Chairman of Victrex in October 2014 to take the Chairman of the Board role at Croda in September 2015 Frew is a non-executive director of: Lloyds Banking Group.
Frew has one son, a diplomat
Prime Bank Kenya is a commercial bank in Kenya and supervised by the Central Bank of Kenya, the central bank and national banking regulator. The bank is a mid-sized retail bank that caters to corporate clients; as of December 2017, the bank's total asset base was valued at KES:77.998 Billion, with shareholders' equity of KES:14.672 Billion. As at July 2018, Prime Bank was the 15th largest commercial bank in Kenya, out of a total of 39 lenders, based on total assets. At that time, the bank had 24,000 deposit accounts and 4,000 loan accounts, with a market share of 1.82 percent, according to data provided by CBK. The bank investments include: Prime Capital & Credit Limited – Based in Nairobi, Kenya is owned 100% by Prime Bank First Merchant Bank – A retail bank based in Blantyre, Malawi – Prime Bank has a 22.48% shareholding in First Merchant Bank. 11.24% is held directly by PBKL while the remaining 11.24% is held through its 100% subsidiary, PCCL. Capital Bank – A commercial bank based in Gaborone, Botswana, is 51% owned by First Merchant Bank of Malawi, in which Prime Bank has 22.48% shareholding.
Therefore, Prime Bank owns 11.46% of Capital Bank of Botswana. As of July 2018, the bank maintained a network of more than 20 interconnected branches in Kenya's major urban centers; the stock of the bank is held. As of January 2019, the bank's stock was owned by the following corporate entities and individuals: List of banks in Kenya Central Bank of Kenya Economy of Kenya