Bat
Bats are mammals of the order Chiroptera. Bats are more manoeuvrable than birds, flying with their long spread-out digits covered with a thin membrane or patagium; the smallest bat, arguably the smallest extant mammal, is Kitti's hog-nosed bat, 29–34 mm in length, 15 cm across the wings and 2–2.6 g in mass. The largest bats are the flying foxes and the giant golden-crowned flying fox, Acerodon jubatus, which can weigh 1.6 kg and have a wingspan of 1.7 m. The second largest order of mammals, bats comprise about 20% of all classified mammal species worldwide, with over 1,200 species; these were traditionally divided into two suborders: the fruit-eating megabats, the echolocating microbats. But more recent evidence has supported dividing the order into Yinpterochiroptera and Yangochiroptera, with megabats as members of the former along with several species of microbats. Many bats are insectivores, most of the rest are frugivores. A few species feed on animals other than insects. Most bats are nocturnal, many roost in caves or other refuges.
Bats are present throughout the world, with the exception of cold regions. They are important in their ecosystems for dispersing seeds. Bats provide humans at the cost of some threats. Bat dung has been used as fertiliser. Bats consume insect pests, they are sometimes numerous enough to serve as tourist attractions, are used as food across Asia and the Pacific Rim. They are natural reservoirs such as rabies. In many cultures, bats are popularly associated with darkness, witchcraft and death. An older English name for bats is flittermouse, which matches their name in other Germanic languages, related to the fluttering of wings. Middle English had bakke, most cognate with Old Swedish natbakka, which may have undergone a shift from -k- to -t- influenced by Latin blatta, "moth, nocturnal insect"; the word "bat" was first used in the early 1570s. The name "Chiroptera" derives from Ancient Greek: χείρ – cheir, "hand" and πτερόν – pteron, "wing"; the delicate skeletons of bats do not fossilise well, it is estimated that only 12% of bat genera that lived have been found in the fossil record.
Most of the oldest known bat fossils were very similar to modern microbats, such as Archaeopteropus. The extinct bats Palaeochiropteryx tupaiodon and Hassianycteris kumari are the first fossil mammals whose colouration has been discovered: both were reddish-brown. Bats were grouped in the superorder Archonta, along with the treeshrews and primates. Modern genetic evidence now places bats in the superorder Laurasiatheria, with its sister taxon as Fereuungulata, which includes carnivorans, odd-toed ungulates, even-toed ungulates, cetaceans. One study places Chiroptera as a sister taxon to odd-toed ungulates; the phylogenetic relationships of the different groups of bats have been the subject of much debate. The traditional subdivision into Megachiroptera and Microchiroptera reflected the view that these groups of bats had evolved independently of each other for a long time, from a common ancestor capable of flight; this hypothesis recognised differences between microbats and megabats and acknowledged that flight has only evolved once in mammals.
Most molecular biological evidence supports the view that bats form a monophyletic group. Genetic evidence indicates that megabats originated during the early Eocene, belong within the four major lines of microbats. Two new suborders have been proposed. Yangochiroptera includes the other families of a conclusion supported by a 2005 DNA study. A 2013 phylogenomic study supported the two new proposed suborders. In the 1980s, a hypothesis based on morphological evidence stated the Megachiroptera evolved flight separately from the Microchiroptera; the flying primate hypothesis proposed that, when adaptations to flight are removed, the Megachiroptera are allied to primates by anatomical features not shared with Microchiroptera. For example, the brains of megabats have advanced characteristics. Although recent genetic studies support the monophyly of bats, debate continues about the meaning of the genetic and morphological evidence; the 2003 discovery of an early fossil bat from the 52 million year old Green River Formation, Onychonycteris finneyi, indicates that flight evolved before echolocative abilities.
Onychonycteris had claws on all five of its fingers, whereas modern bats have at most two claws on two digits of each hand. It had longer hind legs and shorter forearms, similar to climbing mammals that hang under branches, such as sloths and gibbons; this palm-sized bat had short, broad wings, suggesting that it could not fly as fast or as far as bat species. Instead of flapping its wings continuously while flying, Onychonycteris alternated between flaps and
Villefranche-de-Conflent
Villefranche-de-Conflent is a town in the Conflent region of Catalonia, now a commune in the Pyrénées-Orientales department in southern France. Villefranche-de-Conflent is located in the canton of Les Pyrénées catalanes and in the arrondissement of Prades; the town's confined site, at about 440 m above sea level, is level ground surrounded by the northeast-flowing river Têt, the Cady, which flows north to empty into the Têt, a peak, less than 800 m away. RoadsThe N116 from Perpignan on the Mediterranean passes, as a two-lane highway, between the southern town wall and an embankment cut into the high ground to the south. TrainThe town's train station ends the route of the scenic Yellow train; the original town dates from 1098, was fortified because of its strategic position in lands that changed hands between French and Spanish occupation. In 1374, Villefranche resisted the siege of Jaume III the son of last king of Majorca. In July 1654, the French captured the city after eight days, the troops of Louis XIV took Puigcerda from the Spaniards.
The town was part of the program of construction and improvement of outlying French defenses led by through 1707 by Marshal Vauban, as such is listed as a World Heritage Site. The defensive walls of the town remain. Communes of the Pyrénées-Orientales department Les Plus Beaux Villages de France Ayats, Alain, "Les fortifications de Vauban", Trabucaire, 2005, ISBN 2-84974-026-8 INSEE commune file Webpage about the fortifications Webpage about Fort Liberia near Villefranche
Third rail
A third rail is a method of providing electric power to a railway locomotive or train, through a semi-continuous rigid conductor placed alongside or between the rails of a railway track. It is used in a mass transit or rapid transit system, which has alignments in its own corridors or fully segregated from the outside environment. Third rail systems are always supplied from direct current electricity; the third-rail system of electrification is unrelated to the third rail used in dual gauge railways. Third-rail systems are a means of providing electric traction power to trains using an additional rail for the purpose. On most systems, the conductor rail is placed on the sleeper ends outside the running rails, but in some systems a central conductor rail is used; the conductor rail is supported on ceramic insulators or insulated brackets at intervals of around 10 feet. The trains have metal contact blocks called collector shoes which make contact with the conductor rail; the traction current is returned to the generating station through the running rails.
In the US, the conductor rail is made of high conductivity steel or steel bolted to aluminium to increase the conductivity. Elsewhere in the world, extruded aluminum conductors with stainless steel contact surface or cap, is the preferred technology due to its lower electrical resistance, longer life, lighter weight; the running rails are electrically connected using wire bonds or other devices, to minimise resistance in the electric circuit. Contact shoes can be positioned below, above, or beside the third rail, depending on the type of third rail used: these third rails are referred to as bottom-contact, top-contact, or side-contact, respectively; the conductor rails have to be interrupted at level crossings and substation gaps. Tapered rails are provided at the ends of each section, to allow a smooth engagement of the train's contact shoes; the position of contact between the train and the rail varies: some of the earliest systems used top contact, but developments use side or bottom contact, which enabled the conductor rail to be covered, protecting track workers from accidental contact and protecting the conductor rail from frost, ice and leaf-fall.
Because third rail systems present electric shock hazards close to the ground, high voltages are not considered safe. A high current must therefore be used to transfer adequate power, resulting in high resistive losses, requiring closely spaced feed points; the electrified rail threatens electrocution of anyone falling onto the tracks. This can be avoided by using platform screen doors, or the risk can be reduced by placing the conductor rail on the side of the track away from the platform, when allowed by the station layout; the risk can be reduced by having an insulated coverboard to protect the third rail from contact, although many systems do not use one. In some modern systems such as the ground-level power supply, the safety problem is avoided by splitting the power rail into small segments, each of, only powered when covered by a train. There is a risk of pedestrians walking onto the tracks at level crossings. In the US, a 1992 Supreme Court of Illinois decision affirmed a $1.5 million verdict against the Chicago Transit Authority for failing to stop an intoxicated person from walking onto the tracks at a level crossing in an attempt to urinate.
The Paris Metro has graphic warning signs pointing out the danger of electrocution from urinating on third rails, precautions which Chicago did not have. The end ramps of conductor rails present a practical limitation on speed due to the mechanical impact of the shoe, 160 km/h is considered the upper limit of practical third-rail operation; the world speed record for a third rail train is 174 km/h attained on 11 April 1988 by a British Class 442 EMU. In the event of a collision with a foreign object, the beveled end ramps of bottom running systems can facilitate the hazard of having the third rail penetrate the interior of a passenger car; this is believed to have contributed to the death of five passengers in the Valhalla train crash of 2015. Third rail systems using top contact are prone to accumulations of snow, or ice formed from refrozen snow, this can interrupt operations; some systems operate dedicated de-icing trains to deposit an oily fluid or antifreeze on the conductor rail to prevent the frozen build-up.
The third rail can be heated to alleviate the problem of ice. Unlike third rail systems, overhead line equipment can be affected by strong winds or freezing rain bringing the wires down and stopping all trains. Thunderstorms can disable the power with lightning strikes on systems with overhead wires, disabling trains if there is a power surge or a break in the wires; because of the gaps in the conductor rail a train can stop in a position where all of its power pickup shoes are in gaps, so that no traction power is available. The train is said to be "gapped". Another train must be brought up behind the stranded train to push it on to the conductor rail, or a jumper cable may be used to supply enough power to the train to get one of its contact shoes back on the third rail. Avoiding this problem requires a minimum length of trains that can be run on a line. Locomotives have either had the backup of an on-board diesel engine system, or have been connected to shoes on the rolling stock; the first idea for feeding elec
Direct current
Direct current is the unidirectional flow of electric charge. A battery is a good example of a DC power supply. Direct current may flow in a conductor such as a wire, but can flow through semiconductors, insulators, or through a vacuum as in electron or ion beams; the electric current flows in a constant direction, distinguishing it from alternating current. A term used for this type of current was galvanic current; the abbreviations AC and DC are used to mean alternating and direct, as when they modify current or voltage. Direct current may be obtained from an alternating current supply by use of a rectifier, which contains electronic elements or electromechanical elements that allow current to flow only in one direction. Direct current may be converted into alternating current with a motor-generator set. Direct current is used as a power supply for electronic systems. Large quantities of direct-current power are used in production of aluminum and other electrochemical processes, it is used for some railways in urban areas.
High-voltage direct current is used to transmit large amounts of power from remote generation sites or to interconnect alternating current power grids. Direct current was produced in 1800 by Italian physicist Alessandro Volta's battery, his Voltaic pile; the nature of how current flowed. French physicist André-Marie Ampère conjectured that current travelled in one direction from positive to negative; when French instrument maker Hippolyte Pixii built the first dynamo electric generator in 1832, he found that as the magnet used passed the loops of wire each half turn, it caused the flow of electricity to reverse, generating an alternating current. At Ampère's suggestion, Pixii added a commutator, a type of "switch" where contacts on the shaft work with "brush" contacts to produce direct current; the late 1870s and early 1880s saw electricity starting to be generated at power stations. These were set up to power arc lighting running on high voltage direct current or alternating current; this was followed by the wide spread use of low voltage direct current for indoor electric lighting in business and homes after inventor Thomas Edison launched his incandescent bulb based electric "utility" in 1882.
Because of the significant advantages of alternating current over direct current in using transformers to raise and lower voltages to allow much longer transmission distances, direct current was replaced over the next few decades by alternating current in power delivery. In the mid-1950s, high-voltage direct current transmission was developed, is now an option instead of long-distance high voltage alternating current systems. For long distance underseas cables, this DC option is the only technically feasible option. For applications requiring direct current, such as third rail power systems, alternating current is distributed to a substation, which utilizes a rectifier to convert the power to direct current; the term DC is used to refer to power systems that use only one polarity of voltage or current, to refer to the constant, zero-frequency, or varying local mean value of a voltage or current. For example, the voltage across a DC voltage source is constant as is the current through a DC current source.
The DC solution of an electric circuit is the solution where all currents are constant. It can be shown that any stationary voltage or current waveform can be decomposed into a sum of a DC component and a zero-mean time-varying component. Although DC stands for "direct current", DC refers to "constant polarity". Under this definition, DC voltages can vary in time, as seen in the raw output of a rectifier or the fluctuating voice signal on a telephone line; some forms of DC have no variations in voltage, but may still have variations in output power and current. A direct current circuit is an electrical circuit that consists of any combination of constant voltage sources, constant current sources, resistors. In this case, the circuit voltages and currents are independent of time. A particular circuit voltage or current does not depend on the past value of any circuit voltage or current; this implies that the system of equations that represent a DC circuit do not involve integrals or derivatives with respect to time.
If a capacitor or inductor is added to a DC circuit, the resulting circuit is not speaking, a DC circuit. However, most such circuits have a DC solution; this solution gives the circuit currents when the circuit is in DC steady state. Such a circuit is represented by a system of differential equations; the solution to these equations contain a time varying or transient part as well as constant or steady state part. It is this steady state part, the DC solution. There are some circuits. Two simple examples are a constant current source connected to a capacitor and a constant voltage source connected to an inductor. In electronics, it is common to refer to a circuit, powered by a DC voltage source such as a battery or the output of a DC power supply as a DC circuit though what is meant is that the circuit is DC powered. DC is found in many extra-low voltage applications and some low-voltage applications where these are powered by batteries or solar power systems. Most electronic circuits require a DC power supply.
Domestic DC installations have differ
Vernet-les-Bains
Vernet-les-Bains is a commune in the Pyrénées-Orientales department in southern France. It is a centre for holidaymakers; the village has a sunny climate and is set in a sheltered valley in the foothills of the Canigou mountain - which rises to a height of 2,785 metres. Vernet-les-Bains is known for its hot water spring. There is a professional spa/therapy centre in the village. Vernet-les-Bains is located in the arrondissement of Prades. Close by is the Yellow train which runs 63 kilometres from Villefranche-de-Conflent up to Mont-Louis and Latour-de-Carol; the line has the highest station in France at 1,593 metres and is both a lifeline during winter conditions and a tourist attraction. There is a "local" bus service between Vernet-les-Bains. Villefranche-de-Conflent is on a regional train line that connects to Perpignan. Village arboretum de Vernet-les-Bains Near the highest point in Vernet-les-Bains, next to the mairie, stands a monument to the Entente Cordiale of 1904, it is the only one of its kind in France.
The pedestal of the monument is made of Canigou granite. On it rest two white marble statues representing France and Britain; the pedestal itself is set upon a circular base. That in turn is located on a raised, level area of ground which covers 1,000 square metres and, bounded by low stone walls; the idea of erecting this monument was conceived around 1912 by the town council and its mayor, Monsieur Joseph Mercader. The wealthy British visitors who came to this health spa at that time supported the project. A committee of prominent French and British patrons was set up to promote the scheme, its leading members were General Joffre. Monsieur Lambert-Violet, a leading Perpignan businessman, gave the land for the memorial to Vernet; the monument itself was the work of the Roussillon sculptor Gustave Violet, who displayed a model of his proposed work in 1913. However, progress came to a halt in 1914 with the outbreak of World War One. Little further happened until August 1920, when it was proclaimed by presidential decree that work on the monument would proceed but that it would be dedicated both to the Entente Cordiale and to the memory of those killed during the war.
At the same time a new appeal was launched for funds to complete the project. Work on erecting the monument soon got underway. Granite was hauled up from the bed of the River St-Vincent in carts pulled by oxen; the stonemason, Monsieur Herbetta, worked up to fourteen hours a day in the sun's full glare and putting into place the enormously heavy blocks of stone. A circle of wrought-iron fencing was erected around the base of the monument. Monsieur Antoine Mercader remembers, as a six-year-old child, how he and other children watched as the craftsman, Monsieur Serra, poured molten lead into small holes in the ground to seal in place the fence's iron bars; when the monument was completed, it bore the following dedications: "To the Entente Cordiale between France and Britain. To the glory of the Allied Nations. To the memory of soldiers from Vernet who died for their country" The Eglise Saint Saturnin in Vernet-les-Bains is a church sitting on a hill with views of the mountains across the river; the church is small and basic, with a sundial on a side wall, a plaque giving some details of the Church.
The plaque states "Chapelle N. D del Puig" - which appears to have been on the site since 863. There are a number of walks from and close to Vernet-les-Bains, it can be used as a base from. Rudyard Kipling, awarded the Nobel Prize for literature in 1907, stayed in Vernet-les-Bains in 1910, 1911 and 1914. At that time, Kipling was well known in France, following the success of the French version of his classic work, The Jungle Book. While he was in Vernet, Kipling wrote about Canigou. In a letter to the Club Alpin, he praised it as "a magician among mountains". Kipling wrote a light-hearted short story entitled Why Snow Falls at Vernet, it makes fun of the English habit of always talking about the weather. Today, the central bridge over the River Cady in Vernet-les-Bains is named after Kipling; the bridge, the town itself, is featured in the Danish thriller film ID:A. Communes of the Pyrénées-Orientales department INSEE commune file Website of the Vernet les Bains tourist office Website of the Vernet les Bains mairie Information in English about Vernet-les-Bains, including information about Rudyard Kipling's visits to Vernet.
"Walks from and near Vernet-les-Bains"
Suspension bridge
A suspension bridge is a type of bridge in which the deck is hung below suspension cables on vertical suspenders. The first modern examples of this type of bridge were built in the early 1800s. Simple suspension bridges, which lack vertical suspenders, have a long history in many mountainous parts of the world; this type of bridge has cables suspended between towers, plus vertical suspender cables that carry the weight of the deck below, upon which traffic crosses. This arrangement allows the deck to arc upward for additional clearance. Like other suspension bridge types, this type is constructed without falsework; the suspension cables must be anchored at each end of the bridge, since any load applied to the bridge is transformed into a tension in these main cables. The main cables continue beyond the pillars to deck-level supports, further continue to connections with anchors in the ground; the roadway is supported by called hangers. In some circumstances, the towers may sit on a bluff or canyon edge where the road may proceed directly to the main span, otherwise the bridge will have two smaller spans, running between either pair of pillars and the highway, which may be supported by suspender cables or may use a truss bridge to make this connection.
In the latter case there will be little arc in the outboard main cables. The earliest suspension bridges were ropes slung across a chasm, with a deck at the same level or hung below the ropes such that the rope had a catenary shape; the Tibetan saint and bridge-builder Thangtong Gyalpo originated the use of iron chains in his version of simple suspension bridges. In 1433, Gyalpo built eight bridges in eastern Bhutan; the last surviving chain-linked bridge of Gyalpo's was the Thangtong Gyalpo Bridge in Duksum en route to Trashi Yangtse, washed away in 2004. Gyalpo's iron chain bridges did not include a suspended deck bridge, the standard on all modern suspension bridges today. Instead, both the railing and the walking layer of Gyalpo's bridges used wires; the stress points. Before the use of iron chains it is thought that Gyalpo used ropes from twisted willows or yak skins, he may have used bound cloth. The first iron chain suspension bridge in the Western world was the Jacob's Creek Bridge in Westmoreland County, designed by inventor James Finley.
Finley's bridge was the first to incorporate all of the necessary components of a modern suspension bridge, including a suspended deck which hung by trusses. Finley patented his design in 1808, published it in the Philadelphia journal, The Port Folio, in 1810. Early British chain bridges included the Dryburgh Abbey Bridge and 137 m Union Bridge, with spans increasing to 176 m with the Menai Bridge, "the first important modern suspension bridge"; the first chain bridge on the German speaking territories was the Chain Bridge in Nuremberg. The Clifton Suspension Bridge is one of the longest of the parabolic arc chain type; the current Marlow suspension bridge was designed by William Tierney Clark and was built between 1829 and 1832, replacing a wooden bridge further downstream which collapsed in 1828. It is the only suspension bridge across the non-tidal Thames; the Széchenyi Chain Bridge, spanning the River Danube in Budapest, was designed by William Clark and it is a larger scale version of Marlow bridge.
An interesting variation is Thornewill and Warham's Ferry Bridge in Burton-on-Trent, where the chains are not attached to abutments as is usual, but instead are attached to the main girders, which are thus in compression. Here, the chains are made from flat wrought iron plates, eight inches wide by an inch and a half thick, rivetted together; the first wire-cable suspension bridge was the Spider Bridge at Falls of Schuylkill, a modest and temporary footbridge built following the collapse of James Finley's nearby Chain Bridge at Falls of Schuylkill. The footbridge's span was 124 m. Development of wire-cable suspension bridges dates to the temporary simple suspension bridge at Annonay built by Marc Seguin and his brothers in 1822, it spanned only 18 m. The first permanent wire cable suspension bridge was Guillaume Henri Dufour's Saint Antoine Bridge in Geneva of 1823, with two 40 m spans; the first with cables assembled in mid-air in the modern method was Joseph Chaley's Grand Pont Suspendu in Fribourg, in 1834.
In the United States, the first major wire-cable suspension bridge was the Wire Bridge at Fairmount in Philadelphia, Pennsylvania. Designed by Charles Ellet, Jr. and completed in 1842, it had a span of 109 m. Ellet's Niagara Falls Suspension Bridge was abandoned before completion, it was used as scaffolding for John A. Roebling's double decker railroad and carriage bridge; the Otto Beit Bridge was the first modern suspension bridge outside the United States built with parallel wire cables. The main forces in a suspension bridge of any type are tension in the cables and compression in the pillars. Since all the force on the pillars is vertically downwards and they are stabilized by the main cables, the pillars can be made quite slender, as on the Severn Bridge, on the Wales-England border. In a suspended deck bridge, cables suspended via towers hold up the road deck; the weight is transferred by the cables to the towers, which in turn transfer the weight to the ground. Assuming a negligible weight as compared to the weight of the deck and vehicles being supported, the main cables of a suspension bridge will form a parabola (very similar
Latour-de-Carol
Latour-de-Carol is a commune in the Pyrénées-Orientales department in southern France. Latour-de-Carol is located in the canton of Les Pyrénées catalanes and in the arrondissement of Prades; the village's main claim to fame is as the site of the international railway station, Gare de Latour-de-Carol-Enveitg. This station is the terminus of three lines, each with different gauges: the Spanish state operator RENFE's 1,668 mm gauge line running north from Barcelona via Ripoll the French state operator SNCF's 1,435 mm gauge line running south from Toulouse via Foix SNCF's 1,000 mm gauge line running west from Villefranche-de-ConflentAs the French and Spanish tracks are different gauges, no trains run the whole way from Toulouse to Barcelona. Passengers have to change trains. Occasional freight-trains cross the border and are worked to Puigcerda, where freight is transferred; the double-track line to Puigcerda consists of two separate tracks with different gauges and electrified at different currents.
September 2011 - the French gauge line across the border is out of use. Spanish passenger trains run across into France to meet up with the French line. No freight services operate. Judging from the Google maps satellite photos, the French line into Puigcerda has been severed and the alignment of the Spanish line changed; the sidings served by the French lines are being left to nature, although the Spanish lines seem well maintained. European route E09 and part of the Route nationale 20 connect Latour-de-Carol with Bourg-Madame and Foix. Break of gauge Communes of the Pyrénées-Orientales department INSEE commune file Railways through Europe: Latour de Carol - Enveigt
