Ductility is a measure of a material's ability to undergo significant plastic deformation before rupture, which may be expressed as percent elongation or percent area reduction from a tensile test. According to Shigley's Mechanical Engineering Design significant denotes about 5.0 percent elongation. See Eq. 2–12, p. 50 for definitions of percent elongation and percent area reduction. Ductility is characterized by a material's ability to be stretched into a wire. From examination of data in Tables A20, A21, A22, A23, A24 in Shigley's Mechanical Engineering Design, 10th Edition, for both ductile and brittle materials, it is possible to postulate a broader quantifiable definition of ductility that does not rely on percent elongation alone. In general, a ductile material must have a measurable yield strength, at which unrecoverable plastic deformation begins, must satisfy one of the following conditions: either have an elongation to failure of at least 5%, or area reduction to rupture at least 20%, or true strain to rupture at least 10%.
Malleability, a similar property, is a material's ability to deform under compressive stress. Both of these mechanical properties are aspects of plasticity, the extent to which a solid material can be plastically deformed without fracture; these material properties are dependent on temperature and pressure. Ductility and malleability are not always coextensive – for instance, while gold has high ductility and malleability, lead has low ductility but high malleability; the word ductility is sometimes used to encompass both types of plasticity. Ductility is important in metalworking, as materials that crack, break or shatter under stress cannot be manipulated using metal-forming processes such as hammering, drawing or extruding. Malleable materials can be formed cold using stamping or pressing, whereas brittle materials may be cast or thermoformed. High degrees of ductility occur due to metallic bonds, which are found predominantly in metals, leading to the common perception that metals are ductile in general.
In metallic bonds valence shell electrons are shared between many atoms. The delocalized electrons allow metal atoms to slide past one another without being subjected to strong repulsive forces that would cause other materials to shatter. Ductility can be quantified by the fracture strain ε f, the engineering strain at which a test specimen fractures during a uniaxial tensile test. Another used measure is the reduction of area at fracture q; the ductility of steel varies depending on the alloying constituents. Increasing the levels of carbon decreases ductility. Many plastics and amorphous solids, such as Play-Doh, are malleable; the most ductile metal is platinum and the most malleable metal is gold. When stretched, such metals distort via formation and migration of dislocations and crystal twins without noticeable hardening; the ductile–brittle transition temperature, nil ductility temperature, or nil ductility transition temperature of a metal is the temperature at which the fracture energy passes below a predetermined value.
DBTT is important since, once a material is cooled below the DBTT, it has a much greater tendency to shatter on impact instead of bending or deforming. For example, zamak 3 exhibits good ductility at room temperature but shatters when impacted at sub-zero temperatures. DBTT is a important consideration in selecting materials that are subjected to mechanical stresses. A similar phenomenon, the glass transition temperature, occurs with glasses and polymers, although the mechanism is different in these amorphous materials. In some materials, the transition is sharper than others and requires a temperature-sensitive deformation mechanism. For example, in materials with a body-centered cubic lattice the DBTT is apparent, as the motion of screw dislocations is temperature sensitive because the rearrangement of the dislocation core prior to slip requires thermal activation; this can be problematic for steels with a high ferrite content. This famously resulted in serious hull cracking in Liberty ships in colder waters during World War II, causing many sinkings.
DBTT can be influenced by external factors such as neutron radiation, which leads to an increase in internal lattice defects and a corresponding decrease in ductility and increase in DBTT. The most accurate method of measuring the DBTT of a material is by fracture testing. Four point bend testing at a range of temperatures is performed on pre-cracked bars of polished material. For experiments conducted at higher temperatures, dislocation activity increases. At a certain temperature, dislocations shield the crack tip to such an extent that the applied deformation rate is not sufficient for the stress intensity at the crack-tip to reach the critical value for fracture; the temperature at which this occurs is the ductile–brittle transition temperature. If experiments are performed at a higher strain rate, more dislocation shielding is required to prevent brittle fracture, the transition temperature is raised. Deformation Work hardening, which improves ductility in uniaxial tension by delaying the onset of instability Strength of materials Ductility definition at engineersedge.com DoITPoMS Teaching and Learning Package- "The Ductile-Brittle Transition
American Bridge Company
The American Bridge Company is a heavy/civil construction firm that specializes in building and renovating bridges and other large, complex structures. Founded in 1900, the company is headquartered in a suburb of Pittsburgh. Employing the best planners and civil engineers, the firm has built many bridges in the U. S. and elsewhere. American Bridge has built or helped build the Willis Tower, the Empire State Building, the Chrysler Building, launch pads and more. During World War II, it produced tank landing ships for the United States Navy. American Bridge Company was founded in April 1900, when JP Morgan led a consolidation of 28 of the largest U. S. steel constructors. The company’s roots extend to the late 1860s, when one of the consolidated firms, Keystone Bridge Company, built the Eads Bridge at St. Louis, the first steel bridge over the Mississippi River and still in use. In 1902, the company became a subsidiary of United States Steel as part of the Steel Trust consolidation; the company pioneered the use of steel as a construction material.
It went on to do work around the world. During World War II, the company built warships for the U. S. Navy. In 1944, American painter Thomas Hart Benton recorded the construction and launch of LST 768, producing numerous drawings and a painting, Cut the Line; the company went private in 1987 and was sold to Continental Engineering Corporation in 1988. The town of Ambridge, was an American Bridge company town, is near their current headquarters of Coraopolis, Pennsylvania. Both municipalities are on the Ohio River near Pittsburgh, with access to many steel suppliers, as well as to waterborne and rail transport, to allow shipment of components and subassemblies; this is a representative list, not an exhaustive one. Puente Negro, Culiacan, México Hercilio Luz Bridge, Florianópolis, Brazil Silver Bridge, Point Pleasant, West Virginia San Francisco–Oakland Bay Bridge, California Exchange Street Bridge, Massachusetts Mackinac Bridge, Mackinac Straits, Michigan Verrazano-Narrows Bridge, New York Harbor Macarthur Causeway, Florida Built the longest concrete segmental cable stay bridge in the United States Sunshine Skyway Bridge, Tampa Bay, Florida Built the longest suspension bridge in South America, one of the longest in Europe.
Orinoco Bridge, Venezuela 25th of April Bridge, Portugal Built the world's longest arch bridge on three occasions. New River Gorge Bridge, West Virginia, 1977, 518 meters, Bayonne Bridge, Staten Island-New Jersey, 1932, 504 meters Hell Gate Bridge, New York City, 1916, 298 meters Built the world’s longest self-supporting continuous truss bridge. Astoria Bridge, Oregon, 1966, 376 meters Renovations of existing bridges Moved an existing Norfolk Southern vertical lift bridge from Florence, Alabama, to Hannibal, First aerial spinning for additional main cables on a loaded operational suspension bridge. 25 April Bridge in Lisbon, Portugal First stiffening truss replacement on a loaded operational suspension bridge. Lions Gate Bridge, British Columbia, Canada The ongoing Eastern span replacement of the San Francisco–Oakland Bay Bridge, in a joint venture with Fluor Corporation, American Bridge-Fluor. Built the world’s tallest building on numerous occasions. Willis Tower, Chicago, 1974, 443 meters Empire State Building, New York City, 1932, 381 meters Chrysler Building, New York City, 1931, 319 meters Woolworth Building, New York City, 1913, 241 meters Built many other well-known buildings.
John Hancock Center, Chicago Aon Center, Chicago Columbia Seafirst Center, Seattle U. S. Steel Tower, 1970 Flatiron Building, New York City, 1902 Built the world’s largest building by volume twice. Vehicle Assembly Building, Kennedy Space Center, 1964 Boeing 747 Assembly Building, Washington, 1974 Built two of the most notable domed stadium structures in the world Louisiana Superdome, 1974 Houston Astrodome, 1964 Space launch complex jacking for McDonnell Douglas Astronautics Built bottom framework for the unique, modular room units for Walt Disney Company at the Contemporary Resort in Walt Disney World. Hammerhead Crane, 350ton Cantilever type, Cardwell v. American Bridge Co. Continental Engineering Corporation American Bridge Company home page Hoovers fact sheet on ABC HAER record of at least 81 ABC bridges/projects American Bridge Company Chronological history from the company site Old Economy Village history page with American Bridge Company history. News article on American Bridge legacy Another article on legacy
Isambard Kingdom Brunel
Isambard Kingdom Brunel, was an English mechanical and civil engineer, considered "one of the most ingenious and prolific figures in engineering history", "one of the 19th-century engineering giants", "one of the greatest figures of the Industrial Revolution, changed the face of the English landscape with his groundbreaking designs and ingenious constructions". Brunel built dockyards, the Great Western Railway, a series of steamships including the first propeller-driven transatlantic steamship, numerous important bridges and tunnels, his designs revolutionised modern engineering. Though Brunel's projects were not always successful, they contained innovative solutions to long-standing engineering problems. During his career, Brunel achieved many engineering firsts, including assisting in the building of the first tunnel under a navigable river and development of SS Great Britain, the first propeller-driven, ocean-going, iron ship, when built in 1843, was the largest ship built. Brunel set the standard for a well-built railway, using careful surveys to minimise gradients and curves.
This necessitated expensive construction techniques, new bridges, new viaducts, the two-mile long Box Tunnel. One controversial feature was the wide gauge, a "broad gauge" of 7 ft 1⁄4 in, instead of what was to be known as "standard gauge" of 4 ft 8 1⁄2 in, he astonished Britain by proposing to extend the Great Western Railway westward to North America by building steam-powered, iron-hulled ships. He designed and built three ships that revolutionised naval engineering: the SS Great Western, the SS Great Britain, the SS Great Eastern. In 2002, Brunel was placed second in a BBC public poll to determine the "100 Greatest Britons". In 2006, the bicentenary of his birth, a major programme of events celebrated his life and work under the name Brunel 200. Brunel's given names come from his parents; the first name Isambard was his French-born father's middle name, his father's preferred given name. Isambard is a Norman name of Germanic origin, meaning either "iron-bright" or "iron-axe"; the first element comes from isarn meaning iron.
The second element comes from barđa. His middle name Kingdom was his mother's maiden name; the son of French civil engineer Sir Marc Isambard Brunel and an English mother Sophia Kingdom, Isambard Kingdom Brunel was born on 9 April 1806 in Britain Street, Portsmouth, where his father was working on block-making machinery. He had two older sisters and Emma, the whole family moved to London in 1808 for his father's work. Brunel had a happy childhood, despite the family's constant money worries, with his father acting as his teacher during his early years, his father taught him drawing and observational techniques from the age of four and Brunel had learned Euclidean geometry by eight. During this time he learned fluent French and the basic principles of engineering, he was encouraged to identify any faults in their structure. When Brunel was eight he was sent to Dr Morrell's boarding school in Hove, where he learned the classics, his father, a Frenchman by birth, was determined that Brunel should have access to the high-quality education he had enjoyed in his youth in France.
When Brunel was 15, his father Marc, who had accumulated debts of over £5,000, was sent to a debtors' prison. After three months went by with no prospect of release, Marc let it be known that he was considering an offer from the Tsar of Russia. In August 1821, facing the prospect of losing a prominent engineer, the government relented and issued Marc £5,000 to clear his debts in exchange for his promise to remain in Britain; when Brunel completed his studies at Henri-IV in 1822, his father had him presented as a candidate at the renowned engineering school École Polytechnique, but as a foreigner he was deemed ineligible for entry. Brunel subsequently studied under the prominent master clockmaker and horologist Abraham-Louis Breguet, who praised Brunel's potential in letters to his father. In late 1822, having completed his apprenticeship, Brunel returned to England. Brunel worked for several years as an assistant engineer on the project to create a tunnel under London's River Thames between Rotherhithe and Wapping, with tunnellers driving a horizontal shaft from one side of the river to the other under the most difficult and dangerous conditions.
The project was funded by the Thames Tunnel Company and Brunel's father, was the chief engineer. The American Naturalist said "It is stated that the operations of the Teredo suggested to Mr. Brunel his method of tunneling the Thames."The composition of the riverbed at Rotherhithe was little more than waterlogged sediment and loose gravel. An ingenious tunnelling shield designed by Marc Brunel helped protect workers from cave-ins, but two incidents of severe flooding halted work for long periods, killing several workers and badly injuring the younger Brunel; the latter incident, in 1828, killed the two most senior miners, Brunel himself narrowly escaped death. He was injured, spent six months recuperating; the event stopped work on the tunnel for several years. Though the Thames Tunnel was completed during Marc Brunel's lifetime, his son had no further involvement with the tunnel proper, only using the abandoned works at Rotherhithe to further his abortive Gaz experiments; this was based on an idea of his father's, was intended to develop into an engine that ran
Clifton Suspension Bridge
The Clifton Suspension Bridge is a suspension bridge spanning the Avon Gorge and the River Avon, linking Clifton in Bristol to Leigh Woods in North Somerset. Since opening in 1864, it has been a toll bridge, the income from which provides funds for its maintenance; the bridge is built to a design by William Henry Barlow and John Hawkshaw, based on an earlier design by Isambard Kingdom Brunel. It is a grade; the idea of building a bridge across the Avon Gorge originated in 1753. Original plans were for a stone bridge and iterations were for a wrought iron structure. In 1831, an attempt to build Brunel's design was halted by the Bristol riots, the revised version of his designs was built after his death and completed in 1864. Although similar in size, the bridge towers are not identical in design, the Clifton tower having side cut-outs, the Leigh tower more pointed arches atop a 110-foot red sandstone-clad abutment. Roller-mounted "saddles" at the top of each tower allow movement of the three independent wrought iron chains on each side when loads pass over the bridge.
The bridge deck is suspended by 162 vertical wrought-iron rods in 81 matching pairs. The Clifton Bridge Company managed the bridge under licence from a charitable trust; the trust subsequently purchased the company shares, completing this in 1949 and took over the running of the bridge using the income from tolls to pay for maintenance. The bridge is a distinctive landmark, used as a symbol of Bristol on postcards, promotional materials, informational web sites, it has been used as a backdrop to several films and television advertising and programmes. It has been the venue for significant cultural events such as the first modern bungee jump in 1979, the last Concorde flight in 2003 and a handover of the Olympic Torch relay in 2012, it is unknown when the first bridge was constructed across the Avon in Bristol, but the first stone bridge, Bristol Bridge, was built in the 13th century. It had houses with shopfronts built on it to pay for its maintenance. A 17th-century illustration shows that these bridge houses were five storeys high, including the attic rooms, that they overhung the river much as Tudor houses would overhang the street.
In the 1760s a bill to replace the bridge was carried through parliament by the Bristol MP Sir Jarrit Smyth. By the early 18th century, increase in traffic and the encroachment of shops on the roadway made the bridge fatally dangerous for many pedestrians. A new bridge, designed by James Bridges and finished by Thomas Paty was built in 1769 and 1776. Resentment at the tolls exacted to cross the new bridge occasioned the Bristol Bridge Riot of 1793. Other crossings were considered, but were restricted by Admiralty rules that stipulated that any bridge had to be at least 100 feet above the water to allow the passage of tall-masted warships to Bristol Harbour. To achieve this, any bridge constructed between Bristol Bridge and Avon Gorge, from Hotwells to Ashton Gate, would require massive embankments and viaducts; the alternative was to build across the narrowest point of the Avon Gorge, well above the height required for shipping. In 1753 Bristolian merchant William Vick had left a bequest in his will of £1,000, invested with instructions that when the interest had accumulated to £10,000, it should be used for the purpose of building a stone bridge between Clifton Down and Leigh Woods in Somerset.
Although there was little development in the area before the late 18th century, as Bristol became more prosperous, Clifton became fashionable and more wealthy merchants moved to the area. In 1793 William Bridges published plans for a stone arch with abutments containing factories, which would pay for the upkeep of the bridge; the French Revolutionary Wars broke out soon after the design was published, affecting trade and commerce, so the plans were shelved. In 1811 Sarah Guppy patented a design for a suspension bridge across the gorge but this was never realised and was not submitted to the competition. By 1829, Vick's bequest had reached £8,000, but it was estimated that a stone bridge would cost over ten times that. A competition was held to find a design for the bridge with a prize of 100 guineas. Entries were received from 22 designers, including Samuel Brown, James Meadows Rendel, William Tierney Clark and William Hazledine. Several were for stone bridges and had estimated costs of between £30,000 and £93,000.
Brunel submitted four entries. The judging committee rejected 17 of the 22 plans submitted, on the grounds of cost, they called in Scottish civil engineer Thomas Telford to make a final selection from the five remaining entries. Telford rejected all the remaining designs. Telford was asked to produce a design himself, which he did, proposing a 110-foot-wide suspension bridge, supported on tall Gothic towers, costing £52,000. An Act of Parliament was passed to allow a wrought iron suspension bridge to be built instead of stone, tolls levied to recoup the cost. A company was formed and funds raised during the first few months of 1830, but the money raised was not sufficient for the construction. Despite this, the act received Royal Assent in May 1830. Brunel produced a new proposal costing £10,000 less than Telford's design and gained support for it in the local press. James Meadows Rendel, William Armstrong and William Hill submitted new, cheaper proposals, complaining that the committee had not set a budget.
In 1831 a second competition was held, with new judges including Davies Gilbert and John Seaward examining the engineering qualities of the proposals. Thirteen d
Budapest is the capital and the most populous city of Hungary, the tenth-largest city in the European Union by population within city limits. The city had an estimated population of 1,752,704 in 2016 distributed over a land area of about 525 square kilometres. Budapest is both a city and county, forms the centre of the Budapest metropolitan area, which has an area of 7,626 square kilometres and a population of 3,303,786, comprising 33 percent of the population of Hungary; the history of Budapest began when an early Celtic settlement transformed into the Roman town of Aquincum, the capital of Lower Pannonia. The Hungarians arrived in the territory in the late 9th century; the area was pillaged by the Mongols in 1241. Buda, the settlements on the west bank of the river, became one of the centres of Renaissance humanist culture by the 15th century; the Battle of Mohács in 1526 was followed by nearly 150 years of Ottoman rule. After the reconquest of Buda in 1686, the region entered a new age of prosperity.
Pest-Buda became a global city with the unification of Buda, Óbuda, Pest on 17 November 1873, with the name'Budapest' given to the new capital. Budapest became the co-capital of the Austro-Hungarian Empire, a great power that dissolved in 1918, following World War I; the city was the focal point of the Hungarian Revolution of 1848, the Battle of Budapest in 1945, the Hungarian Revolution of 1956. Budapest is an Alpha − global city with strengths in commerce, media, fashion, technology and entertainment, it is Hungary's financial centre and the highest ranked Central and Eastern European city on Innovation Cities Top 100 index, as well ranked as the second fastest-developing urban economy in Europe. Budapest is the headquarters of the European Institute of Innovation and Technology, the European Police College and the first foreign office of the China Investment Promotion Agency. Over 40 colleges and universities are located in Budapest, including the Eötvös Loránd University, the Semmelweis University and the Budapest University of Technology and Economics.
Opened in 1896, the city's subway system, the Budapest Metro, serves 1.27 million, while the Budapest Tram Network serves 1.08 million passengers daily. Budapest is cited as one of the most beautiful cities in Europe, ranked as "the world's second best city" by Condé Nast Traveler, "Europe's 7th most idyllic place to live" by Forbes. Among Budapest's important museums and cultural institutions is the Museum of Fine Arts. Further famous cultural institutions are the Hungarian National Museum, House of Terror, Franz Liszt Academy of Music, Hungarian State Opera House and National Széchényi Library; the central area of the city along the Danube River is classified as a UNESCO World Heritage Site and has many notable monuments, including the Hungarian Parliament, Buda Castle, Fisherman's Bastion, Gresham Palace, Széchenyi Chain Bridge, Matthias Church and the Liberty Statue. Other famous landmarks include Andrássy Avenue, St. Stephen's Basilica, Heroes' Square, the Great Market Hall, the Nyugati Railway Station built by the Eiffel Company of Paris in 1877 and the second-oldest metro line in the world, the Millennium Underground Railway.
The city has around 80 geothermal springs, the largest thermal water cave system, second largest synagogue, third largest Parliament building in the world. Budapest attracts 4.4 million international tourists per year, making it a popular destination in Europe. The separate towns of Buda, Óbuda, Pest were in 1873 unified and given the new name Budapest. Before this, the towns together had sometimes been referred to colloquially as "Pest-Buda". Pest has been sometimes used colloquially as a shortened name for Budapest. All varieties of English pronounce the -s- as in the English word pest; the -u in Buda- is pronounced either /u/ like food or /ju/ like cue. In Hungarian, the -s- is pronounced /ʃ/ as in wash; the origins of the names "Buda" and "Pest" are obscure. The first name comes from: Buda was the name of the first constable of the fortress built on the Castle Hill in the 11th century or a derivative of Bod or Bud, a personal name of Turkic origin, meaning'twig'. or a Slavic personal name, the short form of Budimír, Budivoj.
Linguistically, however, a German origin through the Slavic derivative вода is not possible, there is no certainty that a Turkic word comes from the word buta ~ buda'branch, twig'. According to a legend recorded in chronicles from the Middle Ages, "Buda" comes from the name of its founder, brother of Hunnic ruler Attila. There are several theories about Pest. One states that the name derives from Roman times, since there was a local fortress called by Ptolemaios "Pession". Another has it that Pest originates in the Slavic word for пещера, or peštera. A third cites pešt, referencing a cave where fires burned or a limekiln; the first settlement on the territory of Budapest was built by Celts before 1 AD. It was occupied by the Romans; the Roman settlement – Aquincum – became the main city of Pannonia Inferior in 106 AD. At first it was a military settlement, the city rose around it, making it the focal point of the city's commercial life. Today this area corresponds to the Óbuda district within Budapest.
The Romans constructed roads, amphitheaters and houses with heated floors in this fortified military camp. The Roman city of Aquincum is the best-conserved of the Roman sites in Hungary; the archaeological site was turned into a museum with open-air sections. The Magyar tribes led by Árpád, forc
The Menai Strait is a narrow stretch of shallow tidal water about 25 km long, which separates the island of Anglesey from the mainland of Wales. The strait is bridged in two places: the Menai Suspension Bridge carrying the A5, Robert Stephenson's 1850 Britannia Tubular Bridge; the Britannia carried rail traffic in two wrought-iron rectangular box spans but after a disastrous fire in 1970, which left only the limestone pillars remaining, it was rebuilt as a steel box girder bridge, now carries both rail and road traffic. Between the two bridge crossings there is a small island in the middle of the strait, Ynys Gorad Goch, on which are built a house and outbuildings and around which are the significant remains of fish traps, no longer used; the strait varies in width from 400 metres from Fort Belan to Abermenai Point to 1,100 metres from Traeth Gwyllt to Caernarfon Castle. It narrows to 500 metres in the middle reaches and it broadens again. At Bangor, Garth Pier, it is 900 metres wide, it widens out, the distance from Puffin Island to Penmaenmawr is about 8 kilometres.
The differential tides at the two ends of the strait cause strong currents to flow in both directions through the strait at different times, creating dangerous conditions. One of the most dangerous areas of the strait is known as the Swellies between the two bridges. Here rocks near the surface cause over-falls and local whirlpools, which can be of considerable danger in themselves and cause small boats to founder on the rocks; this was the site of the loss of the training ship HMS Conway in 1953. Entering the strait at the Caernarfon end is hazardous because of the shifting sand banks that make up Caernarfon bar. On the mainland side at this point is Fort Belan, an 18th-century defensive fort built in the times of the American War of Independence; the present day channel is a result of glacial erosion of the bedrock along a line of weakness associated with the Menai Strait Fault System. During the series of Pleistocene glaciations a succession of ice-sheets moved from northeast to southwest across Anglesey and neighbouring Arfon scouring the underlying rock, the grain of which runs in this direction.
The result was a series of linear bedrock hollows across the region, the deepest of, flooded by the sea as world ocean levels rose at the end of the last ice age. The name Menai comes from main-aw or main-wy, meaning "narrow water."According to Heimskringla, the 11th century Norse-Gael ruler Echmarcach mac Ragnaill plundered in Wales with his friend, the Viking Guttorm Gunnhildsson. However they fought a battle at the Menai Strait. Guttorm won the battle by praying to Saint Olaf and Echmarcach was killed. In the 12th century, a Viking raid and battle in the Menai Strait are recounted in the Orkneyinga Saga as playing an important role in the life of Magnus Erlendsson, Earl of Orkney – the future Saint Magnus, he had a reputation for gentleness. Refusing to fight in the raid on Anglesey, he stayed on board his ship; this incident is recounted at length in the 1973 novel Magnus by Orcadian author George Mackay Brown, in the 1977 opera, The Martyrdom of St Magnus by Peter Maxwell Davies. The first of the opera's nine parts is called "The Battle of Menai Strait".
From the 1890s until 1963, the pleasure steamers of the Liverpool and North Wales Steamship Company would ply their main route from Liverpool and Llandudno along the Menai Strait, around Anglesey. After the company's voluntary liquidation in 1962, P and A Campbell took over the services for a while. Now, every year for two weeks in the summer, the MV Balmoral undertakes a similar service; the tidal effects observed along the banks of the strait can be confusing. A rising tide approaches from the south-west, causing the water in the strait to flow north-eastwards as the level rises; the tide flows around Anglesey until, after a few hours, it starts to flow into the strait in a south-westerly direction from Beaumaris. By the time this happens the tidal flow from the Caernarfon end is weakening and the tide continues to rise in height but the direction of tidal flow is reversed. A similar sequence is seen in reverse on a falling tide; this means that slack water between the bridges tends to occur one hour before high tide or low tide.
Theoretically it is possible to ford the strait in the Swellies at low water, spring tides when the depth may fall to less than 0.5 metres. However, at these times a strong current of around 4.8 knots is running, making the passage difficult. Elsewhere in the strait the minimum depth is never less than 2 metres until the great sand flats at Lavan sands are reached beyond Bangor; the tides carry large quantities of fish, the construction of Fish weirs on both banks and on several of the islands, helped make the Strait an important source of fish for many centuries. Eight of the numerous Menai Strait fish weirs are now Scheduled monuments; because the strait has such unusual tidal conditions, coupled with low wave heights because of its sheltered position, it presents a unique and diverse benthic ecology. The depth of the channel reaches 15 metres in places, the current can exceed 7 knots, it is rich in sponges. The existence of this unique ecology was a major factor in the establishment of Bangor University's School of Ocean Sciences at Menai Bridge, as well as its status as a special area of conservation with marine components.
The waters are a proposed Marine Na
Gallipolis is a chartered village in the U. S. state of Ohio and the county seat of Gallia County. The municipality is located in Southeast Ohio along the Ohio River; the population was 3,641 at the 2010 census. When the population dropped below 5,000, Gallipolis lost its city status and was classified as a village under state law, it continues to operate its government under its existing city charter. Gallipolis is the second-largest community in the rural Point Pleasant Micropolitan Statistical Area, which includes all of Gallia County and Mason County, West Virginia. Gallipolis was first settled by Europeans in 1790: "The French 500" were a group of French aristocrats and artisans who were fleeing the violence and disruption of the French Revolution, they were led by an Alsatian member of the French National Assembly. It is the second city to be founded in the newly organized Northwest Territory of the United States, it is known as "The Old French City" because of this beginning. This was a time of rampant land speculation in the Northwest Territory opened for settlement after it was organized following the Northwest Indian Wars.
The French had worked with the Scioto Company, a purported land development company registered in Paris in 1789, paying its agents for land along the Ohio River. They sailed to the United States on several ships, most to Alexandria, outside Washington, DC. From there they traveled by the Ohio River to reach Gallipolis; the French were taken aback by the undeveloped frontier they encountered. When they arrived at the Gallipolis area, they learned; the Scioto Company did not own the land. They survived somehow, building cabins close together in what is now City Park, with a defensive palisade and bastions. In 1795 President George Washington's administration granted the settlers free land in the French Grant in southwest present-day Scioto County, Ohio. Under the terms of this grant, settlers had to live on the land for 5 years and show cultivation in order to become owners. Settlers who chose to stay in Gallipolis had to pay again for their plots, this time to the Ohio Company. Most either arranged to have tenants farm it.
On November 30, 1893, the Asylum for Epileptics and Epileptic Insane, a state-run asylum for persons with epilepsy. It would become the Gallipolis Developmental Center, still operational today serving 52 patients with developmental disabilities in the Appalachian Ohio region; the name Gallipolis is a construct of the Greek or Latin prefix "Galli-" and the Greek suffix "-polis", meaning "city of the French". A US post office called Gallipolis began operating there in 1794. Gallipolis is located at 38°48′55″N 82°11′51″W, along the Ohio River in Appalachia. According to the United States Census Bureau, the village has a total area of 3.83 square miles, of which 3.60 square miles is land and 0.23 square miles is water. Gallipolis is located in the unglaciated hills of southeastern Ohio. Gallipolis City Park is located centrally in the city and is the site of original settlement by 18th-century French refugees. Cassius M. Canaday Memorial Playground is in the village's east end. Sports facilities include Cliffside Golf Club.
The waterworks facility on Chestnut Street has green space and some ballfields. Haskins Memorial Park is contiguous with the golf club; the Elizabeth L. Evans Waterfowl and Bird Sanctuary are adjacent to Memorial Field, which features a skate park; the Texas Road Wildlife Area is located close by. The village operates the Pine Street and Mound Hill cemeteries. Mound Hill Park is adjacent to the cemetery. At least two persons of the founding French 500 were buried in Mound Hill cemetery, it was established in 1880 but had been used for burials before that. Gallipolis, like most of the state of Ohio, has a humid continental climate transitioning into the neighboring subtropical climate; the village experiences four distinct seasons, with hot, muggy summers, cold, dry winters. The village is part of USDA Hardiness zone 6b. October is the driest month, with an average of 2.86 inches of precipitation. Winters are cold, with an average January temperature of 34.3 °F. Snowfall is very light, with a mean average snowfall of 10.9 inches.
The village does not get affected by lake-effect snow, although the village's weather can be influenced by the Great Lakes and regional topography. On average, there are 109 nights per year that drop to or below freezing, only 14 days that fail to rise above freezing. Summers are hot, with an average July temperature of 78.6 °F. There are an average of 39 days per year with highs at or above 90 °F. Precipitation is heavier from the late spring to early summer, on average Gallipolis receives 40.3 inches of precipitation annually. Like many places in the Midwest, Gallipolis is subject to severe weather. During the spring and summer, severe thunderstorms may be accompanied by lightning, hail and tornadoes; the most notable tornado event was the 1968 Wheelersburg tornado outbreak. The population in this rural village has declined since its peak in 1960; as of the census of 2010, there were 3,641 people, 1,576 households, 854 families residing in the village. The populat