Tungsten, or wolfram, is a chemical element with symbol W and atomic number 74. The name tungsten comes from the former Swedish name for the tungstate mineral scheelite, tung sten or "heavy stone". Tungsten is a rare metal found on Earth exclusively combined with other elements in chemical compounds rather than alone, it was identified as a new element in 1781 and first isolated as a metal in 1783. Its important ores include scheelite; the free element is remarkable for its robustness the fact that it has the highest melting point of all the elements discovered, melting at 3422 °C. It has the highest boiling point, at 5930 °C, its density is 19.3 times that of water, comparable to that of uranium and gold, much higher than that of lead. Polycrystalline tungsten is an intrinsically hard material, making it difficult to work. However, pure single-crystalline tungsten can be cut with a hard-steel hacksaw. Tungsten's many alloys have numerous applications, including incandescent light bulb filaments, X-ray tubes, electrodes in gas tungsten arc welding and radiation shielding.
Tungsten's hardness and high density give it military applications in penetrating projectiles. Tungsten compounds are often used as industrial catalysts. Tungsten is the only metal from the third transition series, known to occur in biomolecules that are found in a few species of bacteria and archaea, it is the heaviest element known to be essential to any living organism. However, tungsten interferes with molybdenum and copper metabolism and is somewhat toxic to more familiar forms of animal life. In its raw form, tungsten is a hard steel-grey metal, brittle and hard to work. If made pure, tungsten retains its hardness, becomes malleable enough that it can be worked easily, it is worked by drawing, or extruding. Tungsten objects are commonly formed by sintering. Of all metals in pure form, tungsten has the highest melting point, lowest vapor pressure, the highest tensile strength. Although carbon remains solid at higher temperatures than tungsten, carbon sublimes at atmospheric pressure instead of melting, so it has no melting point.
Tungsten has the lowest coefficient of thermal expansion of any pure metal. The low thermal expansion and high melting point and tensile strength of tungsten originate from strong covalent bonds formed between tungsten atoms by the 5d electrons. Alloying small quantities of tungsten with steel increases its toughness. Tungsten exists in two major crystalline forms: α and β; the former is the more stable form. The structure of the β phase is called A15 cubic. Contrary to the α phase which crystallizes in isometric grains, the β form exhibits a columnar habit; the α phase has one third of the electrical resistivity and a much lower superconducting transition temperature TC relative to the β phase: ca. 0.015 K vs. 1–4 K. The TC value can be raised by alloying tungsten with another metal; such tungsten alloys are sometimes used in low-temperature superconducting circuits. Occurring tungsten consists of four stable isotopes and one long-lived radioisotope, 180W. Theoretically, all five can decay into isotopes of element 72 by alpha emission, but only 180W has been observed to do so, with a half-life of ×1018 years.
The other occurring isotopes have not been observed to decay, constraining their half-lives to be at least 4 × 1021 years. Another 30 artificial radioisotopes of tungsten have been characterized, the most stable of which are 181W with a half-life of 121.2 days, 185W with a half-life of 75.1 days, 188W with a half-life of 69.4 days, 178W with a half-life of 21.6 days, 187W with a half-life of 23.72 h. All of the remaining radioactive isotopes have half-lives of less than 3 hours, most of these have half-lives below 8 minutes. Tungsten has 11 meta states, with the most stable being 179mW. Elemental tungsten resists attack by oxygen and alkalis; the most common formal oxidation state of tungsten is +6, but it exhibits all oxidation states from −2 to +6. Tungsten combines with oxygen to form the yellow tungstic oxide, WO3, which dissolves in aqueous alkaline solutions to form tungstate ions, WO2−4. Tungsten carbides are produced by heating powdered tungsten with carbon. W2C is resistant to chemical attack, although it reacts with chlorine to form tungsten hexachloride.
In aqueous solution, tungstate gives the heteropoly acids and polyoxometalate anions under neutral and acidic conditions. As tungstate is progressively treated with acid, it first yields the soluble, metastable "paratungstate A" anion, W7O6–24, which over time converts to the less soluble "paratungstate B" anion, H2W12O10–42. Further acidification produces the soluble metatungstate anion, H2W12O6–40, after which equilibrium is reached; the metatungstate ion exists as a symmetric cluster of twelve tungsten-oxygen octahedra known as the Keggin anion. Many other polyoxometalate anions exist as metastable species; the inclusion of a different atom such as phosphorus in place of the two central hydrogens in metatungstate produces a wide v
Captain James Cook was a British explorer, navigator and captain in the Royal Navy. He made detailed maps of Newfoundland prior to making three voyages to the Pacific Ocean, during which he achieved the first recorded European contact with the eastern coastline of Australia and the Hawaiian Islands, the first recorded circumnavigation of New Zealand. Cook joined the British merchant navy as a teenager and joined the Royal Navy in 1755, he saw action in the Seven Years' War and subsequently surveyed and mapped much of the entrance to the Saint Lawrence River during the siege of Quebec, which brought him to the attention of the Admiralty and Royal Society. This acclaim came at a crucial moment in his career and the direction of British overseas exploration, led to his commission in 1766 as commander of HM Bark Endeavour for the first of three Pacific voyages. In three voyages, Cook sailed thousands of miles across uncharted areas of the globe, he mapped lands from New Zealand to Hawaii in the Pacific Ocean in greater detail and scale not charted by Western explorers.
As he progressed in his voyages of discovery, he surveyed and named features, recorded islands and coastlines on European maps for the first time. He displayed a combination of seamanship, superior surveying and cartographic skills, physical courage, an ability to lead men in adverse conditions. Cook was attacked and killed in 1779 during his third exploratory voyage in the Pacific while attempting to kidnap Hawaiian chief Kalaniʻōpuʻu in order to reclaim a cutter stolen from one of his ships, he left a legacy of scientific and geographical knowledge which influenced his successors well into the 20th century, numerous memorials worldwide have been dedicated to him. James Cook was born on 7 November 1728 in the village of Marton in Yorkshire and baptised on 14 November in the parish church of St Cuthbert, where his name can be seen in the church register, he was the second of eight children of James Cook, a Scottish farm labourer from Ednam in Roxburghshire, his locally born wife, Grace Pace, from Thornaby-on-Tees.
In 1736, his family moved to Airey Holme farm at Great Ayton, where his father's employer, Thomas Skottowe, paid for him to attend the local school. In 1741, after five years' schooling, he began work for his father, promoted to farm manager. Despite not being formally educated he became capable in mathematics and charting by the time of his Endeavour voyage. For leisure, he would climb Roseberry Topping, enjoying the opportunity for solitude. Cooks' Cottage, his parents' last home, which he is to have visited, is now in Melbourne, having been moved from England and reassembled, brick by brick, in 1934. In 1745, when he was 16, Cook moved 20 miles to the fishing village of Staithes, to be apprenticed as a shop boy to grocer and haberdasher William Sanderson. Historians have speculated that this is where Cook first felt the lure of the sea while gazing out of the shop window. After 18 months, not proving suited for shop work, Cook travelled to the nearby port town of Whitby to be introduced to friends of Sanderson's, John and Henry Walker.
The Walkers, who were Quakers, were prominent local ship-owners in the coal trade. Their house is now the Captain Cook Memorial Museum. Cook was taken on as a merchant navy apprentice in their small fleet of vessels, plying coal along the English coast, his first assignment was aboard the collier Freelove, he spent several years on this and various other coasters, sailing between the Tyne and London. As part of his apprenticeship, Cook applied himself to the study of algebra, trigonometry and astronomy—all skills he would need one day to command his own ship, his three-year apprenticeship completed, Cook began working on trading ships in the Baltic Sea. After passing his examinations in 1752, he soon progressed through the merchant navy ranks, starting with his promotion in that year to mate aboard the collier brig Friendship. In 1755, within a month of being offered command of this vessel, he volunteered for service in the Royal Navy, when Britain was re-arming for what was to become the Seven Years' War.
Despite the need to start back at the bottom of the naval hierarchy, Cook realised his career would advance more in military service and entered the Navy at Wapping on 17 June 1755. Cook married Elizabeth Batts, the daughter of Samuel Batts, keeper of the Bell Inn in Wapping and one of his mentors, on 21 December 1762 at St Margaret's Church, Essex; the couple had six children: James, Elizabeth, Joseph and Hugh. When not at sea, Cook lived in the East End of London, he attended St Paul's Church, where his son James was baptised. Cook has no direct descendants—all of his children died before having children of their own. Cook's first posting was with HMS Eagle, serving as able seaman and master's mate under Captain Joseph Hamar for his first year aboard, Captain Hugh Palliser thereafter. In October and November 1755, he took part in Eagle's capture of one French warship and the sinking of another, following which he was promoted to boatswain in addition to his other duties, his first temporary command was in March 1756 when he was master of Cruizer, a small cutter attached to Eagle while on patrol.
In June 1757 Cook formally passed his master's examinations at Trinity House, qualifying him to navigate and handle a ship of the King's fleet. He joined the frigate
Presbyterianism is a part of the reformed tradition within Protestantism, which traces its origins to Britain Scotland. Presbyterian churches derive their name from the presbyterian form of church government, governed by representative assemblies of elders. A great number of Reformed churches are organized this way, but the word Presbyterian, when capitalized, is applied uniquely to churches that trace their roots to the Church of Scotland, as well as several English dissenter groups that formed during the English Civil War. Presbyterian theology emphasizes the sovereignty of God, the authority of the Scriptures, the necessity of grace through faith in Christ. Presbyterian church government was ensured in Scotland by the Acts of Union in 1707, which created the Kingdom of Great Britain. In fact, most Presbyterians found in England can trace a Scottish connection, the Presbyterian denomination was taken to North America by Scots and Scots-Irish immigrants; the Presbyterian denominations in Scotland hold to the Reformed theology of John Calvin and his immediate successors, although there is a range of theological views within contemporary Presbyterianism.
Local congregations of churches which use presbyterian polity are governed by sessions made up of representatives of the congregation. The roots of Presbyterianism lie in the Reformation of the 16th century, the example of John Calvin's Republic of Geneva being influential. Most Reformed churches that trace their history back to Scotland are either presbyterian or congregationalist in government. In the twentieth century, some Presbyterians played an important role in the ecumenical movement, including the World Council of Churches. Many Presbyterian denominations have found ways of working together with other Reformed denominations and Christians of other traditions in the World Communion of Reformed Churches; some Presbyterian churches have entered into unions with other churches, such as Congregationalists, Lutherans and Methodists. Presbyterians in the United States came from Scottish immigrants, Scotch-Irish immigrants, from New England Yankee communities, Congregational but changed because of an agreed-upon Plan of Union of 1801 for frontier areas.
Along with Episcopalians, Presbyterians tend to be wealthier and better educated than most other religious groups in United States, are disproportionately represented in the upper reaches of American business and politics. Presbyterian tradition that of the Church of Scotland, traces its early roots to the Church founded by Saint Columba, through the 6th century Hiberno-Scottish mission. Tracing their apostolic origin to Saint John, the Culdees practiced Christian monasticism, a key feature of Celtic Christianity in the region, with a presbyter exercising "authority within the institution, while the different monastic institutions were independent of one another." The Church in Scotland kept the Christian feast of Easter at a date different from the See of Rome and its monks used a unique style of tonsure. The Synod of Whitby in 664, ended these distinctives as it ruled "that Easter would be celebrated according to the Roman date, not the Celtic date." Although Roman influence came to dominate the Church in Scotland, certain Celtic influences remained in the Scottish Church, such as "the singing of metrical psalms, many of them set to old Celtic Christianity Scottish traditional and folk tunes", which became a "distinctive part of Scottish Presbyterian worship".
Presbyterian history is part of the history of Christianity, but the beginning of Presbyterianism as a distinct movement occurred during the 16th-century Protestant Reformation. As the Catholic Church resisted the reformers, several different theological movements splintered from the Church and bore different denominations. Presbyterianism was influenced by the French theologian John Calvin, credited with the development of Reformed theology, the work of John Knox, a Scotsman and a Roman Catholic Priest, who studied with Calvin in Geneva, Switzerland, he brought back Reformed teachings to Scotland. The Presbyterian church traces its ancestry back to England and Scotland. In August 1560 the Parliament of Scotland adopted the Scots Confession as the creed of the Scottish Kingdom. In December 1560, the First Book of Discipline was published, outlining important doctrinal issues but establishing regulations for church government, including the creation of ten ecclesiastical districts with appointed superintendents which became known as presbyteries.
In time, the Scots Confession would be supplanted by the Westminster Confession of Faith, the Larger and Shorter Catechisms, which were formulated by the Westminster Assembly between 1643 and 1649. Presbyterians distinguish themselves from other denominations by doctrine, institutional organization and worship; the origins of the Presbyterian churches are in Calvinism. Many branches of Presbyterianism are remnants of previous splits from larger groups; some of the splits have been due to doctrinal controversy, while some have been caused by disagreement concerning the degree to which those ordained to church office should be required to agree with the Westminster Confession of Faith, which serves as an important confessional document – second only to the Bible, yet directing particularities in the standardization and translation of the Bible – in Presbyterian churches. Presbyteria
Captain Matthew Flinders was an English navigator and cartographer who led the first circumnavigation of Australia and identified it as a continent. Flinders made three voyages to the southern ocean between 1791 and 1810. In the second voyage, George Bass and Flinders confirmed. In the third voyage, Flinders circumnavigated the mainland of what was to be called Australia, accompanied by Aboriginal man Bungaree. Heading back to England in 1803, Flinders' vessel needed urgent repairs at Isle de France. Although Britain and France were at war, Flinders thought the scientific nature of his work would ensure safe passage, but a suspicious governor kept him under arrest for more than six years. In captivity, he recorded details of his voyages for future publication, put forward his rationale for naming the new continent'Australia', as an umbrella term for New Holland and New South Wales – a suggestion taken up by Governor Macquarie. Flinders' health had suffered and although he reached home in 1810, he did not live to see the success of his praised book and atlas, A Voyage to Terra Australis.
The location of his grave was lost by the mid-19th century but archaeologists excavating a former burial ground near London's Euston railway station for the High Speed 2 project, announced in January 2019 that his remains had been identified. Matthew Flinders was born in Donington, England, the son of Matthew Flinders, a surgeon, his wife Susannah, née Ward, he was educated at Cowley's Charity School, from 1780 and at the Reverend John Shinglar's Grammar School at Horbling in Lincolnshire. In his own words, he was "induced to go to sea against the wishes of my friends from reading Robinson Crusoe", in 1790, at the age of fifteen, he joined the Royal Navy. Serving on HMS Alert, he transferred to HMS Scipio, in July 1790 was made midshipman on HMS Bellerophon under Captain Pasley. By Pasley's recommendation, he joined Captain Bligh's expedition on HMS Providence, transporting breadfruit from Tahiti to Jamaica; this was Bligh's second "Breadfruit Voyage" following on from the ill-fated voyage of the Bounty.
Flinders' first voyage to New South Wales, first trip to Port Jackson, was in 1795 as a midshipman aboard HMS Reliance, carrying the newly appointed governor of New South Wales Captain John Hunter. On this voyage he established himself as a fine navigator and cartographer, became friends with the ship's surgeon George Bass, three years his senior and had been born 11 miles from Donington. Not long after their arrival in Port Jackson and Flinders made two expeditions in two small open boats, named Tom Thumb and Tom Thumb II respectively: the first to Botany Bay and Georges River, the second, in the larger Tom Thumb II, south from Port Jackson to Lake Illawarra, during which expedition they had to seek shelter at Wattamolla. In 1798, Matthew Flinders, now a lieutenant, was given command of the sloop Norfolk with orders "to sail beyond Furneaux's Islands, should a strait be found, pass through it, return by the south end of Van Diemen's Land"; the passage between the Australian mainland and Tasmania enabled savings of several days on the journey from England, was named Bass Strait, after his close friend.
In honour of this discovery, the largest island in Bass Strait would be named Flinders Island. The town of Flinders near the mouth of Western Port commemorates Bass' discovery of that bay and port on 4 January 1798. Flinders never entered Western Port, passed Cape Schanck only on 3 May 1802. Flinders once more sailed Norfolk, this time north on 17 July 1799, he touched down at Pumicestone Passage and Coochiemudlo Island and rowed ashore at Clontarf. During this visit he named Redcliffe after the Red Cliffs. In March 1800, Flinders set sail for England. Flinders' work had come to the attention of many of the scientists of the day, in particular the influential Sir Joseph Banks, to whom Flinders dedicated his Observations on the Coasts of Van Diemen's Land, on Bass's Strait, etc.. Banks used his influence with Earl Spencer to convince the Admiralty of the importance of an expedition to chart the coastline of New Holland; as a result, in January 1801, Flinders was given command of HMS Investigator, a 334-ton sloop, promoted to commander the following month.
Investigator set sail for New Holland on 18 July 1801. Attached to the expedition were the botanist Robert Brown, botanical artist Ferdinand Bauer, landscape artist William Westall, gardener Peter Good, geological assistant John Allen, John Crosley as astronomer. Vallance et al. comment that compared to the Baudin expedition this was a'modest contingent of scientific gentlemen', which reflects'British parsimony' in scientific endeavour. On 17 April 1801, Flinders married his longtime friend Ann Chappelle and had hoped to bring her with him to Port Jackson; however the Admiralty had strict rules against wives accompanying captains. Flinders brought Ann on board ship and planned to ignore the rules, but the Admiralty learned of his plans and he was chastised for his bad judgement and told he must remove her from the ship; this is well documented in correspondence between Flinders and his chief benefactor, Sir Joseph Banks, in May 1801: I have but time to tell you that the news of your marriage, published in the Lincoln paper, has reached me.
The Lords of the Admiralty have heard that Mrs. Flinders is on board the Investigator, that you have some thought of carrying her to sea with you; this I was sorry to hear, if, the case I beg to give you my
A thunderstorm known as an electrical storm or a lightning storm, is a storm characterized by the presence of lightning and its acoustic effect on the Earth's atmosphere, known as thunder. Weak thunderstorms are sometimes called thundershowers. Thunderstorms occur in a type of cloud known as a cumulonimbus, they are accompanied by strong winds, produce heavy rain and sometimes snow, sleet, or hail, but some thunderstorms produce little precipitation or no precipitation at all. Thunderstorms may become a rainband, known as a squall line. Strong or severe thunderstorms include some of the most dangerous weather phenomena, including large hail, strong winds, tornadoes; some of the most persistent severe thunderstorms, known as supercells, rotate as do cyclones. While most thunderstorms move with the mean wind flow through the layer of the troposphere that they occupy, vertical wind shear sometimes causes a deviation in their course at a right angle to the wind shear direction. Thunderstorms result from the rapid upward movement of moist air, sometimes along a front.
As the warm, moist air moves upward, it cools and forms a cumulonimbus cloud that can reach heights of over 20 kilometres. As the rising air reaches its dew point temperature, water vapor condenses into water droplets or ice, reducing pressure locally within the thunderstorm cell. Any precipitation falls the long distance through the clouds towards the Earth's surface; as the droplets fall, they become larger. The falling droplets create a downdraft as it pulls cold air with it, this cold air spreads out at the Earth's surface causing strong winds that are associated with thunderstorms. Thunderstorms can form and develop in any geographic location but most within the mid-latitude, where warm, moist air from tropical latitudes collides with cooler air from polar latitudes. Thunderstorms are responsible for the formation of many severe weather phenomena. Thunderstorms, the phenomena that occur along with them, pose great hazards. Damage that results from thunderstorms is inflicted by downburst winds, large hailstones, flash flooding caused by heavy precipitation.
Stronger thunderstorm cells are capable of producing waterspouts. There are four types of thunderstorms: single-cell, multi-cell cluster, multi-cell lines and supercells. Supercell thunderstorms are the most severe. Mesoscale convective systems formed by favorable vertical wind shear within the tropics and subtropics can be responsible for the development of hurricanes. Dry thunderstorms, with no precipitation, can cause the outbreak of wildfires from the heat generated from the cloud-to-ground lightning that accompanies them. Several means are used to study thunderstorms: weather radar, weather stations, video photography. Past civilizations held various myths concerning thunderstorms and their development as late as the 18th century. Beyond the Earth's atmosphere, thunderstorms have been observed on the planets of Jupiter, Saturn and Venus. Warm air has a lower density than cool air, so warmer air rises upwards and cooler air will settle at the bottom. Clouds form as warmer air, carrying moisture, rises within cooler air.
The moist air rises, and, as it does so, it cools and some of the water vapor in that rising air condenses. When the moisture condenses, it releases energy known as latent heat of condensation, which allows the rising packet of air to cool less than the cooler surrounding air continuing the cloud's ascension. If enough instability is present in the atmosphere, this process will continue long enough for cumulonimbus clouds to form and produce lightning and thunder. Meteorological indices such as convective available potential energy and the lifted index can be used to assist in determining potential upward vertical development of clouds. Thunderstorms require three conditions to form: Moisture An unstable airmass A lifting force All thunderstorms, regardless of type, go through three stages: the developing stage, the mature stage, the dissipation stage; the average thunderstorm has a 24 km diameter. Depending on the conditions present in the atmosphere, each of these three stages take an average of 30 minutes.
The first stage of a thunderstorm is developing stage. During this stage, masses of moisture are lifted upwards into the atmosphere; the trigger for this lift can be solar illumination, where the heating of the ground produces thermals, or where two winds converge forcing air upwards, or where winds blow over terrain of increasing elevation. The moisture carried upward cools into liquid drops of water due to lower temperatures at high altitude, which appear as cumulus clouds; as the water vapor condenses into liquid, latent heat is released, which warms the air, causing it to become less dense than the surrounding, drier air. The air tends to rise in an updraft through the process of convection; this process creates a low-pressure zone beneath the forming thunderstorm. In a typical thunderstorm 500 million kilograms of water vapor are lifted into the Earth's atmosphere. In the mature stage of a thunderstorm, the warmed air continues to rise until it reaches an area of warmer air and can rise no farther.
This'cap' is the tropopause. The air is instead forced to spread out; the resulting cloud is called cumulonimbus incus. The water droplets coalesce into heavier droplets and freeze to become ice particles; as these fall, they melt to become rain. If the updraft
RAAF Base Scherger
RAAF Base Scherger is a Royal Australian Air Force military air base located 26 km east of Weipa on the western side of Cape York Peninsula in Queensland, Australia. One of three'bare bases' completing a chain of bases across Australia’s'top end', the base is occupied by a caretaker staff and can be activated at short notice; the base was constructed by troops drawn from the 17th Construction Squadron, in what is believed to have been the biggest project undertaken by the Royal Australian Engineers at the time. Opened on 5 August 1998 by the Prime Minister, John Howard, the base was named in honour of Air Chief Marshal Sir Frederick Scherger, the Australian Chief of the Air Staff from March 1957 to May 1961 and the equivalent of what is now Chief of the Defence Force from 1961 to 1966; as a'bare base' Scherger's role is to provide the RAAF and other services with the necessary infrastructure to support forward deployed forces during a crisis. While the base has facilities to cater for 400 personnel in fixed accommodation, 1,000 personnel in tent lines and about 40 aircraft, it is only manned by four Air Force personnel who are responsible for caretaker duties.
During peacetime RAAF Base Scherger hosts, on average, one major exercise per year in which the base is activated through the arrival of RAAF units based elsewhere in Australia. In October 2010, the Scherger Immigration Detention Centre was opened at Scherger RAAF Base, this facility provided accommodation for 300 single adult males; the centre closed in 2014. List of airports in Queensland List of Royal Australian Air Force installations RAAF Base Scherger at airforce.gov.au Exercise Kakadu VII Air Force News: "Going Active" RAAF Base Scherger opened near Weipa Scherger Immigration Detention Centre