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Capo Caccia Lighthouse
Capo Caccia Lighthouse ( Algherese Catalan: ''Far del Cap de Caça,'' it, Faro di Capo Caccia) is an active 19th century lighthouse situated at the extremity of Capo Caccia, from Tramariglio a frazione of Alghero on the western coast of Sardinia. Description The lighthouse was built in 1864 on the top of the namesake promontory overlooking the sea, just above Neptune's Grotto connected by s staircase of 656 steps named Escala de Cabirol (Staircase of roe). The light station is a three-story white building protected by a Faraday cage to defend from the lightning strikes; above the keeper's house stands the tower high, which was rebuilt in 1950s, bringing the focal height to making it the highest lighthouse in Italy. The lantern was supplied by various fuels, including acetylene up to 1880, and then by petroleum gas, until in 1961 the plant was electrified. The rotating optic which was built in Paris by Barbier, Benard, et Turenne in 1951, is equipped with a Fresnel lens, with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Alghero
Alghero (; ca, label= Alguerese, L'Alguer ; sc, S'Alighèra ; sdc, L'Aliera ) is a city of about 45,000 inhabitants in the Italian insular province of Sassari in northwestern Sardinia, next to the Mediterranean Sea. The city's name comes from ''Aleguerium'', which is a mediaeval Latin word meaning "stagnation of algae" (''Posidonia oceanica''). The population is noted for having retained the language of the Catalan rulers from the end of the Middle Ages, when Sardinia was part of the Crown of Aragon; hence, Alguerese (the Catalan dialect spoken there) is officially recognized as a minority language. Alghero is the third university center in the island, coming after Cagliari and Sassari. It hosts the headquarters of the Università degli Studi di Sassari’s Architecture and Design department. In 2012 it was the 10th most visited city by tourists in Italy. History The area of today's Alghero has been settled since pre-historic times. The Ozieri culture was present h ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sardinia
Sardinia ( ; it, Sardegna, label=Italian, Corsican and Tabarchino ; sc, Sardigna , sdc, Sardhigna; french: Sardaigne; sdn, Saldigna; ca, Sardenya, label=Algherese and Catalan) is the second-largest island in the Mediterranean Sea, after Sicily, and one of the 20 regions of Italy. It is located west of the Italian Peninsula, north of Tunisia and immediately south of the French island of Corsica. It is one of the five Italian regions with some degree of domestic autonomy being granted by a special statute. Its official name, Autonomous Region of Sardinia, is bilingual in Italian and Sardinian: / . It is divided into four provinces and a metropolitan city. The capital of the region of Sardinia — and its largest city — is Cagliari. Sardinia's indigenous language and Algherese Catalan are referred to by both the regional and national law as two of Italy's twelve officially recognized linguistic minorities, albeit gravely endangered, while the regional law provides ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical region. Italy is also considered part of Western Europe, and shares land borders with France, Switzerland, Austria, Slovenia and the enclaved microstates of Vatican City and San Marino. It has a territorial exclave in Switzerland, Campione. Italy covers an area of , with a population of over 60 million. It is the third-most populous member state of the European Union, the sixth-most populous country in Europe, and the tenth-largest country in the continent by land area. Italy's capital and largest city is Rome. Italy was the native place of many civilizations such as the Italic peoples and the Etruscans, while due to its central geographic location in Southern Europe and the Mediterranean, the country has also historically been home ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Focal Length
The focal length of an optical system is a measure of how strongly the system converges or diverges light; it is the inverse of the system's optical power. A positive focal length indicates that a system converges light, while a negative focal length indicates that the system diverges light. A system with a shorter focal length bends the rays more sharply, bringing them to a focus in a shorter distance or diverging them more quickly. For the special case of a thin lens in air, a positive focal length is the distance over which initially collimated (parallel) rays are brought to a focus, or alternatively a negative focal length indicates how far in front of the lens a point source must be located to form a collimated beam. For more general optical systems, the focal length has no intuitive meaning; it is simply the inverse of the system's optical power. In most photography and all telescopy, where the subject is essentially infinitely far away, longer focal length (lower opti ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Algherese Dialect
Algherese or Alguerese (Algherese: ) is the variant of Catalan spoken in the city of Alghero ( in Catalan), in the northwest of Sardinia, Italy. The dialect has its roots in 1372, when Catalan-speaking colonists were allowed to repopulate Alghero and expel the native population, after several revolts. Catalan was replaced as the official language by Spanish, then by Italian in the mid-18th century. Today the language has semi-official recognition alongside Italian. Studies give an approximate number of 20,000 to 30,000 native speakers of the language worldwide. In communities where Algherese is spoken, Italian and Logudorese Sardinian are often used as well. History Algherese is a regional dialect spoken by anywhere from 20,000 to 30,000 individuals, most of whom reside in the town of Alghero, located in the northwest of Sardinia. The language, though distinct, is initially derived from, and thus considered a variant of, the Catalan language. The origins of the language c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lighthouse
A lighthouse is a tower, building, or other type of physical structure designed to emit light from a system of lamps and lenses and to serve as a beacon for navigational aid, for maritime pilots at sea or on inland waterways. Lighthouses mark dangerous coastlines, hazardous shoals, reefs, rocks, and safe entries to harbors; they also assist in aerial navigation. Once widely used, the number of operational lighthouses has declined due to the expense of maintenance and has become uneconomical since the advent of much cheaper, more sophisticated and effective electronic navigational systems. History Ancient lighthouses Before the development of clearly defined ports, mariners were guided by fires built on hilltops. Since elevating the fire would improve the visibility, placing the fire on a platform became a practice that led to the development of the lighthouse. In antiquity, the lighthouse functioned more as an entrance marker to ports than as a warning signal for reefs a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Frazione
A ''frazione'' (plural: ) is a type of subdivision of a ''comune'' (municipality) in Italy, often a small village or hamlet outside the main town. Most ''frazioni'' were created during the Fascist era (1922–1943) as a way to consolidate territorial subdivisions in the country. In the autonomous region of the Aosta Valley, a ''frazione'' is officially called an ''hameau'' in French. Description Typically the term ''frazioni'' applies to the villages surrounding the main town (''capoluogo'') of a ''comune''. Subdivision of a ''comune'' is optional; some ''comuni'' have no ''frazioni'', but others have several dozen. The ''comune'' usually has the same name of the ''capoluogo'', but not always, in which case it is called a ''comune sparso''. In practice, most ''frazioni'' are small villages or hamlets, occasionally just a clump of houses. Not every hamlet is classified as a ''frazione''; those that are not are often referred to as ''località'', for example, in the telephone boo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Neptune's Grotto
Neptune's Grotto ( it, Grotta di Nettuno; ca, Cova de Neptú) is a stalactite cave near the town of Alghero on the island of Sardinia, Italy. The cave was discovered by local fishermen in the 18th century and has since developed into a popular tourist attraction. The grotto gets its name from the Roman god of the sea, Neptune. Overview The entrance to the grotto lies only around a metre above the sea level at the foot of the 110-metre-high ''Capo Caccia'' cliffs and the cave can therefore only be visited when the waters below are calm. A stairway cut into the cliff in 1954, the 654-step ''escala del cabirol'' (goat's steps), leads from a car park at the top of the cliff down to the entrance. The grotto is also accessible via a short boat trip from the port of Alghero; these trips are arranged hourly during the summer, but less frequently during spring and autumn. Two other grottoes lie nearby, the "Green grotto", which is not open to tourists, and the ''Grotta di Ricami'', whic ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Faraday Cage
A Faraday cage or Faraday shield is an enclosure used to block electromagnetic fields. A Faraday shield may be formed by a continuous covering of conductive material, or in the case of a Faraday cage, by a mesh of such materials. Faraday cages are named after scientist Michael Faraday, who invented them in 1836. A Faraday cage operates because an external electrical field causes the electric charges within the cage's conducting material to be distributed so that they cancel the field's effect in the cage's interior. This phenomenon is used to protect sensitive electronic equipment (for example RF receivers) from external radio frequency interference (RFI) often during testing or alignment of the device. They are also used to protect people and equipment against actual electric currents such as lightning strikes and electrostatic discharges, since the enclosing cage conducts current around the outside of the enclosed space and none passes through the interior. Faraday cages ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Acetylene
Acetylene (systematic name: ethyne) is the chemical compound with the formula and structure . It is a hydrocarbon and the simplest alkyne. This colorless gas is widely used as a fuel and a chemical building block. It is unstable in its pure form and thus is usually handled as a solution. Pure acetylene is odorless, but commercial grades usually have a marked odor due to impurities such as divinyl sulfide and phosphine.Compressed Gas Association (1995Material Safety and Data Sheet – Acetylene As an alkyne, acetylene is unsaturated because its two carbon atoms are bonded together in a triple bond. The carbon–carbon triple bond places all four atoms in the same straight line, with CCH bond angles of 180°. Discovery Acetylene was discovered in 1836 by Edmund Davy, who identified it as a "new carburet of hydrogen". It was an accidental discovery while attempting to isolate potassium metal. By heating potassium carbonate with carbon at very high temperatures, he produced a ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Barbier, Benard, Et Turenne
Barbier, Benard, et Turenne (BBT) was a French company founded in 1862, specializing in the manufacture of spotlights, Fresnel lenses for lighthouses, and lighting systems. It was the world's leading producer of lighthouse beacons from the end of the 19th century onwards. It dissolved in 1982. History The company was founded in 1862 by Frederic Barbier and Stanislas Fenestre as Barbier and Fenestre. It was renamed Barbier et Cie in 1887 and Barbier and Bénard in 1889. It became Barbier, Benard, et Turenne early in the 20th century, and became a public limited company in 1919.École des Ponts ParisTech, enpc.fr website,/web-BBT.pdf "Barbier Benard Turenne (BBT), historical note"Thobie, Jacques. '' Administration General beacons of the Ottoman Empire and the Collas and Michel society, 1860-1960 '' (L'Harmattan, 2004), p. 12. Production Lighthouses Barbier, Benard, et Turenne began with a specialty in the production of equipment for lighthouse beacons, such as Fresnel lenses. I ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Fresnel Lens
A Fresnel lens ( ; ; or ) is a type of composite compact lens developed by the French physicist Augustin-Jean Fresnel (1788–1827) for use in lighthouses. It has been called "the invention that saved a million ships." The design allows the construction of lenses of large aperture and short focal length without the mass and volume of material that would be required by a lens of conventional design. A Fresnel lens can be made much thinner than a comparable conventional lens, in some cases taking the form of a flat sheet. The simpler dioptric (purely refractive) form of the lens was first proposed by Count Buffon and independently reinvented by Fresnel. The ''catadioptric'' form of the lens, entirely invented by Fresnel, has outer elements that use total internal reflection as well as refraction; it can capture more oblique light from a light source and add it to the beam of a lighthouse, making the light visible from greater distances. Description The Fresnel lens redu ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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