In physical geography, a dune is a hill of loose sand built by aeolian processes or the flow of water. Dunes occur in different sizes, formed by interaction with the flow of air or water. Most kinds of dunes are longer on the stoss side, where the sand is pushed up the dune, have a shorter "slip face" in the lee side; the valley or trough between dunes is called a slack. A "dune field" or erg is an area covered by extensive dunes. Dunes occur along some coasts; some coastal areas have one or more sets of dunes running parallel to the shoreline directly inland from the beach. In most cases, the dunes are important in protecting the land against potential ravages by storm waves from the sea. Although the most distributed dunes are those associated with coastal regions, the largest complexes of dunes are found inland in dry regions and associated with ancient lake or sea beds. Dunes can form under the action of water flow, on sand or gravel beds of rivers and the sea-bed; the modern word "dune" came into English from French c.
1790, which in turn came from Middle Dutch dūne. Dunes are made of sand-sized particles, may consist of quartz, calcium carbonate, gypsum, or other materials; the upwind/upstream/upcurrent side of the dune is called the stoss side. Sand is pushed or bounces up the stoss side, slides down the lee side. A side of a dune that the sand has slid down is called a slip face; the Bagnold formula gives the speed. Five basic dune types are recognized: crescentic, star and parabolic. Dune areas may occur in three forms: simple and complex. Barchan dunes are crescent-shaped mounds which are wider than they are long; the lee-side slipfaces are on the concave sides of the dunes. These dunes form under winds that blow from one direction, they form separate crescents. When the sand supply is greater, they may merge into barchanoid ridges, transverse dunes; some types of crescentic dunes move more over desert surfaces than any other type of dune. A group of dunes moved more than 100 metres per year between 1954 and 1959 in China's Ningxia Province, similar speeds have been recorded in the Western Desert of Egypt.
The largest crescentic dunes on Earth, with mean crest-to-crest widths of more than three kilometres, are in China's Taklamakan Desert. See lunettes and parabolic dues, for dunes similar to crescent-shaped ones. Abundant barchan dunes may merge into barchanoid ridges, which grade into linear transverse dunes, so called because they lie transverse, or across, the wind direction, with the wind blowing perpendicular to the ridge crest. Seif dunes are linear dunes with two slip faces; the two slip faces make them sharp-crested. They are called seif dunes after the Arabic word for "sword", they may be more than 160 kilometres long, thus visible in satellite images. Seif dunes are associated with bidirectional winds; the long axes and ridges of these dunes extend along the resultant direction of sand movement. Some linear dunes merge to form Y-shaped compound dunes. Formation is debated. Bagnold, in The Physics of Blown Sand and Desert Dunes, suggested that some seif dunes form when a barchan dune moves into a bidirectional wind regime, one arm or wing of the crescent elongates.
Others suggest. In the sheltered troughs between developed seif dunes, barchans may be formed, because the wind is constrained to be unidirectional by the dunes. Seif dunes are common in the Sahara, they range up to 300 km in length. In the southern third of the Arabian Peninsula, a vast erg, called the Rub' al Khali or Empty Quarter, contains seif dunes that stretch for 200 km and reach heights of over 300 m. Linear loess hills known; these hills appear to have been formed during the last ice age under permafrost conditions dominated by sparse tundra vegetation. Radially symmetrical, star dunes are pyramidal sand mounds with slipfaces on three or more arms that radiate from the high center of the mound, they tend to accumulate in areas with multidirectional wind regimes. Star dunes grow upward rather than laterally, they dominate the Grand Erg Oriental of the Sahara. In other deserts, they occur around the margins of the sand seas near topographic barriers. In the southeast Badain Jaran Desert of China, the star dunes are up to 500 metres tall and may be the tallest dunes on Earth.
Oval or circular mounds that lack a slipface. Dome dunes occur at the far upwind margins of sand seas. Fixed crescentic dunes that form on the leeward margins of playas and river valleys in arid and semiarid regions in response to the direction of prevailing winds, are known as lunettes, source-bordering dunes and clay dunes, they may be composed of clay, sand, or gypsum, eroded from the basin floor or shore, transported up the concave side of the dune, deposited on the convex side. Examples in Australia are up to 6.5 km long, 1 km wide, up to 50 metres high. They occur in southern and West Africa, in parts of the western United States Texas. U-shaped mounds of sand with convex noses trailed by elongated arms are parabolic dunes; these dunes are formed from blowout dunes where the erosion
Corrugated galvanised iron
Corrugated galvanised iron or steel is a building material composed of sheets of hot-dip galvanised mild steel, cold-rolled to produce a linear corrugated pattern in them. Although it is still popularly called "iron" in the UK, the material used is steel, only the surviving vintage sheets may be made up of 100% iron; the corrugations increase the bending strength of the sheet in the direction perpendicular to the corrugations, but not parallel to them, because the steel must be stretched to bend perpendicular to the corrugations. Each sheet is manufactured longer in its strong direction. CGI is lightweight and transported, it was and still is used in rural and military buildings such as sheds and water tanks. Its unique properties were used in the development of countries like Australia from the 1840s, it is still helping developing countries today. CGI was invented in the 1820s in Britain by Henry Robinson Palmer and engineer to the London Dock Company, it was made from wrought iron. It proved to be light, corrosion-resistant, transported, lent itself to prefabricated structures and improvisation by semi-skilled workers.
It soon became a common construction material in rural areas in the United States, New Zealand and Australia and India, in Australia and Chile became a common roofing material in urban areas. In Australia and New Zealand it has become part of the cultural identity, fashionable architectural use has become common. CGI is widely used as building material in African slums and informal settlements. For roofing purposes, the sheets are laid somewhat like tiles, with a lateral overlap of one and half corrugations, a vertical overlap of about 150 millimetres, to provide for waterproofing. CGI is a common construction material for industrial buildings throughout the world. Wrought iron CGI was replaced by mild steel from around the 1890s, iron CGI is no longer obtainable but the common name has not been changed. Galvanized sheets with simple corrugations are being displaced by 55% Al-Zn coated steel or coil-painted sheets with complex profiles. CGI remains common. Today the corrugation process is carried out using the process of roll forming.
This modern process is automated to achieve high productivity and low costs associated with labour. In the corrugation process sheet metal is pulled off huge rolls and through rolling dies that form the corrugation. After the sheet metal passes through the rollers it is automatically sheared off at a desired length; the traditional shape of corrugated material is the round wavy style, but different dies form a variety of shapes and sizes. Industrial buildings are build with and covered by trapezoidal sheet metal. Many materials today undergo the corrugation process; the most common materials for corrugated iron are ferrous alloys and copper. Regular ferrous alloys are the most common availability. Common sizes of corrugated material can range from a thin 30 gauge to a thick 6 gauge. Thicker or thinner gauges may be produced. Other materials such as plastic and fibreglass are given the corrugated look. Many applications are available for these products including using them with metal sheets to allow light to penetrate below.
The corrugations are described in terms of depth. It is important for the pitch and depth to be quite uniform, in order for the sheets to be stackable for transport, to overlap neatly when joining two sheets. Pitches have ranged from 25 mm to 125 mm, it was once common for CGI used for vertical walls to have a shorter pitch and depth than roofing CGI. This shorter pitched material was sometimes called "rippled" instead of "corrugated"; however nowadays, nearly all CGI produced has the same pitch of 3 inches. Clapping hands or snapping one’s fingers whilst standing next to perpendicular sheets of corrugated iron will produce a high-pitched echo with a falling pitch; this is due to a sequence of echoes from adjacent corrugations. If sound is traveling at 344 metres per second and the corrugated iron has a wavelength of 3 inches this will produce an echo with a maximum wavelength of that order, which corresponds to a frequency of 4500 Hz or so; the first part of the echo will have a much higher pitch because the sound impulses from iron nearly opposite the clapper will arrive simultaneously.
Although galvanising inhibits the corrosion of steel, rusting is inevitable in marine areas - where the salt water encourages rust - and areas where the local rainfall is acidic. Corroded corrugated steel roofs can last for many many years if the sheetings are protected by a layer of paint. Chattel house Metal roof Nissen hut Tin tabernacle Theorema Egregium, for more information on why corrugation increases strength Heritage Roofing in Victoria, Australia Corrugated Metal Roofing & Paneling
Gibraltar is a British Overseas Territory located at the southern tip of the Iberian Peninsula. It is bordered to the north by Spain; the landscape is dominated by the Rock of Gibraltar at the foot of, a densely populated town area, home to over 30,000 people Gibraltarians. In 1704, Anglo-Dutch forces captured Gibraltar from Spain during the War of the Spanish Succession on behalf of the Habsburg claim to the Spanish throne; the territory was ceded to Great Britain in perpetuity under the Treaty of Utrecht in 1713. During World War II it was an important base for the Royal Navy as it controlled the entrance and exit to the Mediterranean Sea, the Strait of Gibraltar, only 8 miles wide at this naval choke point, it remains strategically important. Today Gibraltar's economy is based on tourism, online gambling, financial services and cargo ship refuelling; the sovereignty of Gibraltar is a point of contention in Anglo-Spanish relations because Spain asserts a claim to the territory. Gibraltarians rejected proposals for Spanish sovereignty in a 1967 referendum and, in a 2002 referendum, the idea of shared sovereignty was rejected.
Evidence of Neanderthal habitation in Gibraltar from around 50,000 years ago has been discovered at Gorham's Cave. The caves of Gibraltar continued to be used by Homo sapiens after the final extinction of the Neanderthals. Stone tools, ancient hearths and animal bones dating from around 40,000 years ago to about 5,000 years ago have been found in deposits left in Gorham's Cave. Numerous potsherds dating from the Neolithic period have been found in Gibraltar's caves of types typical of the Almerian culture found elsewhere in Andalusia around the town of Almería, from which it takes its name. There is little evidence of habitation in the Bronze Age, when people had stopped living in caves. During ancient times, Gibraltar was regarded by the peoples of the Mediterranean as a place of religious and symbolic importance; the Phoenicians were present for several centuries since around 950 BC using Gorham's Cave as a shrine to the genius loci, as did the Carthaginians and Romans after them. Gibraltar was known as Mons Calpe, a name of Phoenician origin.
Mons Calpe was considered by the ancient Greeks and Romans as one of the Pillars of Hercules, after the Greek legend of the creation of the Strait of Gibraltar by Heracles. There is no known archaeological evidence of permanent settlements from the ancient period, they settled at the head of the bay in. The town of Carteia, near the location of the modern Spanish town of San Roque, was founded by the Phoenicians around 950 BC on the site of an early settlement of the native Turdetani people. After the collapse of the Western Roman Empire, Gibraltar came under the control of the Vandals, who crossed into Africa at the invitation of Boniface, the Count of the territory; the area formed part of the Visigothic Kingdom of Hispania for 300 years, from 414 until 711 AD. Following a raid in 710, a predominantly Berber army under the command of Tariq ibn Ziyad crossed from North Africa in April 711 and landed somewhere in the vicinity of Gibraltar. Tariq's expedition led to the Islamic conquest of most of the Iberian peninsula.
Mons Calpe was renamed the Mount of Tariq, subsequently corrupted into Gibraltar. In 1160 the Almohad Sultan Abd al-Mu'min ordered that a permanent settlement, including a castle, be built, it received the name of Medinat al-Fath. The Tower of Homage of the Moorish Castle remains standing today. From 1274 onwards, the town was fought over and captured by the Nasrids of Granada, the Marinids of Morocco and the kings of Castile. In 1462 Gibraltar was captured by 1st Duke of Medina Sidonia. After the conquest, Henry IV of Castile assumed the additional title of King of Gibraltar, establishing it as part of the comarca of the Campo Llano de Gibraltar. Six years Gibraltar was restored to the Duke of Medina Sidonia, who sold it in 1474 to a group of 4350 conversos from Cordova and Seville and in exchange for maintaining the garrison of the town for two years, after which time they were expelled, returning to their home towns or moving on to other parts of Spain. In 1501 Gibraltar passed back to the Spanish Crown, Isabella I of Castile issued a Royal Warrant granting Gibraltar the coat of arms that it still uses.
In 1704, during the War of the Spanish Succession, a combined Anglo-Dutch fleet, representing the Grand Alliance, captured the town of Gibraltar on behalf of the Archduke Charles of Austria in his campaign to become King of Spain. Subsequently most of the population left the town with many settling nearby; as the Alliance's campaign faltered, the 1713 Treaty of Utrecht was negotiated, which ceded control of Gibraltar to Britain to secure Britain's withdrawal from the war. Unsuccessful attempts by Spanish monarchs to regain Gibraltar were made with the siege of 1727 and again with the Great Siege of Gibraltar, during the American War of Independence. Gibraltar became a key base for the Royal Navy and played an important role prior to the Battle of Trafalgar and during the Crimean War of 1854–56, because of its strategic location. In the 18th century, the peacetime military garrison fluctuated in numbers from a minimum of 1,100 to a maximum of 5,000; the first half of the 19th century saw a significant increase of population to more t
A residential area is a land used in which housing predominates, as opposed to industrial and commercial areas. Housing may vary between, through, residential areas; these include multi-family residential, or mobile homes. Zoning for residential use may permit some services or work opportunities or may exclude business and industry, it may only permit low density uses. Residential zoning includes a smaller FAR than business, commercial or industrial/manufacturing zoning; the area may be small. In certain residential areas rural, large tracts of land may have no services whatever, thus residents seeking services must use a motor vehicle or other transport, so the need for transport has resulted in land development following existing or planned transport infrastructure such as rail and road. Development patterns may be regulated by restrictive covenants contained in the deeds to the properties in the development, may result from or be reinforced by zoning. Restrictive covenants are not changed when the agreement of all property owners is required.
The area so restricted may be small. Residential areas may be subcategorized in the concentric zone model and other schemes of urban geography. Residential development is real estate development for residential purposes; some such developments are called a subdivision, when the land is divided into lots with houses constructed on each lot. Such developments became common during the late nineteenth century in the form of streetcar suburbs. In previous centuries, residential development was of two kinds. Rich people bought a townlot, hired an architect and/or contractor, built a bespoke / customized house or mansion for their family. Poor urban people lived in tenements built for rental. Single-family houses were built on speculation, for future sale to residents not yet identified; when cities and the middle class expanded and mortgage loans became commonplace, a method, rare became commonplace to serve the expanding demand for home ownership. Post–World War II economic expansion in major cities of the United States New York City and Los Angeles produced a demand for thousands of new homes, met by speculative building.
Its large-scale practitioners disliked the term "property speculator" and coined the new name "residential development" for their activity. Entire farms and ranches were subdivided and developed with one individual or company controlling all aspects of entitlement, land development and housing. Communities like Levittown, Long Island or Lakewood south of Los Angeles saw new homes sold at unprecedented rates—more than one a day. Many techniques which had made the automobile affordable made housing affordable: standardization of design and small, repetitive assembly tasks, a smooth flow of capital. Mass production resulted in a similar uniformity of product, a more comfortable lifestyle than cramped apartments in the cities. With the advent of government-backed mortgages, it could be cheaper to own a house in a new residential development than to rent; as with other products, continual refinements appeared. Curving streets, greenbelt parks, neighborhood pools, community entry monumentation appeared.
Diverse floor plans with differing room counts, multiple elevations appeared. Developers remained competitive with each other on everything, including location, community amenities, kitchen appliance packages, price. Today, a typical residential development in the United States might include traffic calming features, such as a winding street, dead-end road, or looped road lined with homes. Suburban developments help form the stereotypical image of a "suburban America," and are associated with the American middle-class. Most offer homes in a narrow range of age, price and features, thus potential residents having different needs, wishes or resources must look elsewhere; some residential developments are gated communities. Criticisms of residential developments may include: They do not mesh well with the greater community; some are isolated, with only one entrance, or otherwise connected with the rest of the community in few ways. Being commuter towns, they serve no more purpose for the greater community than other specialized settlements do, thus require residents to go to the greater community for commercial or other purposes.
Whereas mixed-use developments provide for commerce and other activities, thus residents need not go as to the greater community. The dictionary definition of residential at Wiktionary Meadowbrook symbol of postwar housing boom - Pantagraph Residential Property Valuations
Timeline of the history of Gibraltar
The history of Gibraltar portrays how The Rock gained an importance and a reputation far exceeding its size and shaping the people who came to reside here over the centuries. Evidence of hominid inhabitation of the Rock dates back to the Neanderthals. A Neanderthal skull was discovered in Forbes' Quarry in 1848, prior to the "original" discovery in the Neander Valley. In 1926, the skull of a Neanderthal child was found in Devil's Tower. Mousterian deposits found at Gorham's Cave, which are associated with Neanderthals in Europe, have been dated to as as 28,000 to 24,000 BP, leading to suggestions that Gibraltar was one of the last places of Neanderthal habitation. Modern humans visited the Gibraltar area in prehistoric times after the Neanderthal occupancy. While the rest of Europe was cooling, the area around Gibraltar back resembled a European Serengeti. Leopards, lynxes and bears lived among wild cattle, deer, ibexes and rhinos – all surrounded by olive trees and stone pines, with partridges and ducks overhead, tortoises in the underbrush and mussels and other shellfish in the waters.
Clive Finlayson, evolutionary biologist at the Gibraltar Museum said "this natural richness of wildlife and plants in the nearby sandy plains, shrublands, wetlands and coastline helped the Neanderthals to persist." Evidence at the cave shows the Neanderthals of Gibraltar used it as a shelter "for 100,000 years." Cro-Magnon man took over Gibraltar around 24,000 BCE. The Phoenicians are known to have visited the Rock circa 950 BC and named the Rock "Calpe"; the Carthaginians visited. However, neither group appears to have settled permanently. Plato refers to Gibraltar as one of the Pillars of Hercules along with Jebel Musa or Monte Hacho on the other side of the Strait; the Romans visited Gibraltar. Following the fall of the Western Roman Empire, Gibraltar was occupied by the Vandals and the Goths kingdoms; the Vandals did not remain for long although the Visigoths remained on the Iberian peninsula from 414 to 711. The Gibraltar area and the rest of the South Iberian Peninsula was part of the Byzantine Empire during the second part of the 6th century reverting to the Visigoth Kingdom.
711 30 April – The Umayyad general Tariq ibn Ziyad, leading a Berber-dominated army, sailed across the Strait from Ceuta. He first failed. Upon his failure, he landed undetected at the southern point of the Rock from present-day Morocco in his quest for Spain, it was here. Coming from the Arabian words Gabal-Al-Tariq. Little was built during the first four centuries of Moorish control. 1160 – The Almohad Sultan Abd al-Mu'min ordered that a permanent settlement, including a castle, be built. It received the name of Medinat al-Fath. On completion of the works in the town, the Sultan crossed the Strait to inspect the works and stayed in Gibraltar for two months; the Tower of Homage of the castle remains standing today. 1231 – After the collapse of the Almohad Empire, Gibraltar was taken by Ibn Hud, Taifa emir of Murcia. 1237 – Following the death of Ibn Hud, his domains were handed over to Muhammad ibn al-Ahmar, the founder of the Nasrid kingdom of Granada. Therefore, Gibraltar changed hands again. 1274 – The second Nasrid king, Muhammed II al-Faqih, gave Gibraltar over to the Marinids, as payment for their help against the Christian kingdoms.
1309 – While the King Ferdinand IV of Castile laid siege on Algeciras, Alonso Pérez de Guzmán was sent to capture the town. This was the First Siege of Gibraltar; the Castilians took the Upper Rock from. The garrison surrendered after one month. Gibraltar had about 1,500 inhabitants. 1310 31 January – Gibraltar was granted its first Charter by the king Ferdinand IV of Castile. Being considered a high risk town, the charter included incentives to settle there such as the offering of freedom from justice to anyone who lived in Gibraltar for one year and one day; this fact marked the establishment of the Gibraltar council.1316 – Gibraltar was unsuccessfully besieged by the Nasrid caid Yahya. 1333 June – A Marinid army, led by Abd al-Malik, the son of Abul Hassan, the Marinid sultan, recovered Gibraltar, after a five-month siege. King Alfonso XI of Castile attempted to retake Gibraltar aided by the fleet of the Castilian Admiral Alonso Jofre Tenorio. A ditch was dug across the isthmus. While laying the siege, the king was attacked by a Nasrid army from Granada.
Therefore, the siege ended in a truce, allowing the Marinids to keep Gibraltar.1344 March – After the two-year Siege of Algeciras, Algeciras was taken over by the Castilian forces. Therefore, Gibraltar became the main Marinid port in the Iberian Peninsula. During the siege, Gibraltar played a key role as the supply base of the besieged. 1349 – Gibraltar was unsuccessfully besieged by the Castilian forces led by the king Alfonso XI. 1350 – The siege was resumed by Alfonso XI. It was again unsuccessful due to the arrival of the Black Death, which decimated the besiegers, causing the death of the king. 1369 – As the Civil War in Castile came to an end, with the murder of king Peter I by the pretender Henry, the Nasrid king of Granada, Muhammad V, former ally of Peter, took over Algeciras after the 3-day Siege of Algeciras. Ten years the city was razed out to the ground, its harbour made unusable; this fact increased again the importance of Gibraltar, yet in Marinid hands, i
Lieutenant General Sir Herbert Scott Gould Miles, was a senior British Army officer. He was Quartermaster-General to the Forces from 1908 to 1912, Governor of Gibraltar from 1913 until 1918 during the First World War. Miles was commissioned into the 101st Regiment of Foot in 1869, he had a change of career and became a barrister in the Inner Temple in 1880. He rejoined the army becoming Deputy Assistant Quartermaster-General at the War Office in 1889 and Assistant Adjutant-General at Aldershot Command in 1893. In 1898 he was appointed Commandant of the Staff Camberley, he served in the Second Boer War, from early February 1900 as Deputy Adjutant-General and Chief of Staff for the Natal Field Force. After the war he returned to his role at the Staff College and in 1903, became Commander of British Troops in the Cape Colony District, he was appointed Director of Recruiting and Organisation at Army Headquarters in 1904 and Quartermaster-General to the Forces in 1908. He was Governor of Gibraltar from 1913.
Sir Herbert Miles Road in Gibraltar is named in his honour. There is a memorial to him in St Peter's Church in Suffolk. Specific GeneralObituary of Lieut.-General Sir Herbert Miles, The Times, 21 May 1926