The Seikan Submarine Tunnel was opened in March 1988 and runs beneath the seabed of the Tsugaru Strait, which separates the southern edge of Hokkaido from Aomori Prefecture on the northern edge of the mainland. This tunnel is a part of a railway that runs between Aomori City and Hakodate City in just two and a half hours, and was named by combining the two characters and pronunciations of Aomori City's "Ao (Sei)" and Hakodate City's "Hako (Kan)". The length of 53.85 kilometers (33.5 miles) makes it world's longest, though its 23.3 kilometers (14.5 miles) of submarine portion was outdistanced by the 37.5-kilometer (23.3-mile) Euro Tunnel which opened in 1994. The railway track runs 240 meters (787 feet) below the sea surface, and is the deepest railway line in the world. The advanced civil engineering technologies have been rated highly that made it possible for the tunnel to run below 140-meter-deep (459-foot-deep) water as well as 100 meters (328 feet) below the seabed.
The tunnel was designed with gentle curves and slopes for possible future use by Shinkansen (bullet trains). In addition, high-strength rails suitable for Shinkansen (bullet trains) have been used.
There are two stations inside the tunnel: Tappi Kaitei Station on the Aomori side, and Yoshioka Kaitei Station on the Hokkaido side. They are both located just under the coastal line. In these two station buildings-which are rare submarine stations-tour courses have been established with reference displays of the Tsugaru Strait and the Seikan Tunnel.
The Millau Viaduct (French: le Viaduc de Millau) is a large cable-stayed road-bridge that spans the valley of the River Tarn near Millau in southern France. Designed by English architect Norman Foster and French bridge engineer Michel Virlogeux, it is the tallest vehicular bridge in the world, with one pier's summit at 343 metres (1,125 ft)—slightly taller than the Eiffel Tower and only 38 m (125 ft) shorter than the Empire State Building. It was formally dedicated on 14 December 2004 and opened to traffic two days later.
The bridge’s construction broke three world records:
* The highest pylons in the world: pylons P2 and P3, 244.96 and 221.05 metres in height respectively, broke the French record previously held by the Tulle and Verrières Viaducts (141m), and the world record previously held by the Kochertal Viaduct (Germany), which peaked at 181 metres;
* The highest mast in the world: the height of the mast atop pile P2, peaks at 343m.
* The highest road bridge deck in the world, which is 270m above the Tarn River at its highest point. Only the bridge deck of the Royal Gorge Bridge (321m) in Colorado, United States is higher, and is considered the highest bridge in the world.
The Delta Works are a number of constructions that were built between 1950 and 1997 in the southwest of the Netherlands to protect a large area of land from the sea. The works consist of dams, sluices, locks, dikes and storm surge barriers. The aim of the dams, sluices and storm surge barriers was to shorten the Dutch coastline and limit the amount of dikes that were to be heightened.
History
The estuaries of the rivers Rhine, Meuse and Scheldt have been subject to many floodings over the centuries. After building the Afsluitdijk, the Dutch started studying the damming of the Rhine-Meuse Delta. Plans were developed for shortening the coastline and turning the estuary into freshwater lakes. By shortening the coastline less dikes would have to be reinforced.
Due to indecision and the Second World War, these plans remained studies and little action was taken. In 1950 two small estuary mouths, the Brielse Gat near Brielle and the Botlek near Vlaardingen were dammed. After the North Sea flood of 1953, a commission was installed which had to come up with a plan to research the causes and seek measures to prevent such disasters in future. They revised some of the old plans and came up with the so called "Deltaplan".
[edit] Lay-out of the plan
The plan consisted of blocking the estuary-mouths of the Oosterschelde, the Haringvliet and the Grevelingen. This reduced the amount of dykes exposed to the sea by approximately 400 miles. The estuary-mouths of the Nieuwe Waterweg and the Westerschelde were to remain open because of the shipping routes to the ports of Rotterdam and Antwerp. The dikes along these waterways were to be heightened and strengthened. The works would be combined with road and waterway infrastructure to stimulate the economy of the province of Zeeland and improve the connection between the port of Rotterdam and Antwerp.
[edit] Alterations to the plan during the execution of the Works
During the execution of the works alterations were made due to pressure from society. In the Nieuwe Waterweg heightening and the associated widening of the dikes proved very difficult because of many historic buildings standing in the way. Therefore a storm surge barrier would be built (the Maeslantkering) and dikes were only partly heightened.
Oosterscheldekering, the largest of 13 Delta Works' dams.
Oosterscheldekering, the largest of 13 Delta Works' dams.
The Oosterschelde was originally to be dammed and turned into a fresh water lake. The saltwater nature and the fishing of oysters would have then been lost. Environmentalists and fishermen combined their efforts to stop this and successfully pressed parliament to make amendments to the original plan. Instead of completely damming the estuary mouth, a storm surge barrier would be built.
The storm surge barrier only closes when the sea-level is expected to rise above 3 meters above mean sea-level. Under normal conditions the estuary mouth is open and salt water flows in and out with the tide. Consequently, the weak dikes along the Oosterschelde needed to be strengthened. This strengthening had not been done yet because the Oosterschelde would be dammed. Over 200 km of dike needed new revetments. The connections between the Eastern Scheldt and the neighboring Haringvliet had to be dammed to limit the effect of the salt water. Extra dams and locks were needed at the east part of the Oosterschelde to create a shipping route between the ports of Rotterdam and Antwerp.
The idea of a canal linking the Mediterranean to the Red Sea dates back to ancient times. Unlike the modern Canal, earlier ones linked the Red Sea to the Nile, therefore forcing the ships to sail along the River on their journey from Europe to India. It has been suggested that the first Canal was dug during the reign of Tuthmosis III, although more solid evidence credits the Pharaoh Necho (Sixth Century BC) for the attempt. During the Persian invasion of Egypt, King Darius I ordered the Canal completed. The Red Sea Canal, consisted of two parts: the first linking the Gulf of Suez to the Great Bitter Lake, and the second connecting the Lake to one of the Nile branches in the Delta. The canal remained in good condition during the Ptolemaic era, but fell into disrepair afterwards. It was re-dug during the rule of the Roman Emperor Trajan, and later the Arab ruler Amr Ibn-Al-Aas. Over the years, it fell again into disrepair, and was completely abandoned upon the discovery of the trade route around Africa.
It was Napoleon's engineers who, around 1800 AD, revived the idea of a shorter trade route to India via a Suez Canal. However, the calculation carried out by the French engineers showed a difference in level of 10 meters between both seas. If constructed under such circumstances, a large land area would be flooded. Later, the calculations showed to be wrong, and the final attempt to dig the Canal was undertaken by former French Consul in Cairo and famous Canal digger Ferdinand de Lesseps. He was granted a "firman" or decree by the khedive Said of Egypt to run the Canal for 99 years after completion.
In 1859, Egyptian workers started working on the construction of the Canal in conditions described by historians as slave labor, and the project was completed around 1867. On November 17, 1869, the Canal was officially inaugurated by Khedive Ismail in an extravagant and lavish ceremony. French, British, Russian, and other Royalty were invited for the inauguration which coincided with the re-planning of Cairo. A highway was constructed linking Cairo to the new city of Ismailia, an Opera House was built, and Verdi was commissioned to compose his famous opera, "Aida" for the opening ceremony. Ironically, Verdi did not complete the work in time and "Aida" premiered at the Cairo Opera a year later.
The Suez Canal emerged on the political scene in 1956, during the Suez crisis. It was in July of that years the Egyptian president Nasser, at age 38, announced the nationalization of the Canal at Mansheya Square in Alexandria in front of a cheering crowd. His decision was in response to the British, French, and American refusal for a loan aimed at building the Aswan High Dam. The revenue from the Canal, he argued, would help finance the High Dam project. The announcement triggered a swift reaction by Great Britain, France, and Israel, who all invaded Egypt less than two months later. Their action would be condemned by the International community, and Nasser would eventually claim victorious.
In 1967, the Canal was closed at the wake of the Six-Day War, when Israel occupied the Sinai Peninsula, causing the Canal to act as a buffer zone between the fighting forces. The Egyptians reclaimed the Canal upon the 1973 Arab-Israeli War, and the re-opening ceremony took place in 1975. Since then, the Canal, which stretches 167 kms across the Egyptian desert, has been widened twice. Today, approximately 50 ships cross the canal daily, and, with the threat of war long gone, the cities and beaches along the Bitter Lakes and the Canal serve as a summer resort for tourists.
The Internet is a worldwide, publicly accessible network of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP). It is a "network of networks" that consists of millions of smaller domestic, academic, business, and government networks, which together carry various information and services, such as electronic mail, online chat, file transfer, and the interlinked Web pages and other documents of the World Wide Web.
The Panama Canal (Spanish: Canal de Panamá) is a major ship canal that traverses the Isthmus of Panama in Central America, connecting the Atlantic and Pacific Oceans. Construction of the canal was one of the largest and most difficult engineering projects ever undertaken. It has had an enormous impact on shipping between the two oceans, obviating the long and treacherous route via the Drake Passage and Cape Horn at the southernmost tip of South America. A ship sailing from New York to San Francisco via the canal travels 9,500 km (6,000 miles), well under half the distance of the previous 22,500 km (14,000 mi) route around Cape Horn.[1] Although the concept of a canal near Panama dates back to the early 16th century, the first attempt to construct a canal began in 1880 under French leadership. After this attempt failed and saw 20,000 workers die, the project of building a canal was attempted and completed by the United States in Panama in 1914, when the canal opened. The building of the 77 km (48 mi) canal was plagued by problems, including disease (particularly malaria and yellow fever) and landslides. As many as 27,500 workers are estimated to have died during construction of the canal.
Since opening, the canal has been enormously successful, and continues to be a key conduit for international shipping. Each year more than 14,000 ships pass through the canal, carrying more than 203 million tons of cargo. By 2002 about 800,000 ships had used the canal altogether.[2]
The canal can accommodate vessels from small private yachts up to fairly large commercial ships. The maximum size of vessel that can use the canal is known as Panamax; an increasing number of modern ships exceed this limit, and are known as post-Panamax vessels. A typical passage through the canal by a cargo ship takes around nine hours. 14,011 vessels passed through in 2005, with a total capacity of 278.8 million tons, making an average of almost 40 vessels per day.[3]
he canal consists of seventeen artificial lakes, several improved and artificial channels, and two sets of locks. An additional artificial lake, Alajuela Lake, acts as a reservoir for the canal. The layout of the canal as seen by a ship transiting from the Pacific end to the Atlantic is as follows:[4]
A schematic of the Panama Canal, illustrating the sequence of locks and passages
Due to the local geography the main direction of sailing is North-West, whereas the global direction from Pacific to Atlantic is East.
From the beginning of the buoyed entrance channel in the Gulf of Panama, ships travel 13.2 kilometres (8.2 mi) up the channel to the Miraflores locks, passing under the Bridge of the Americas
The two-stage Miraflores lock system, including the approach wall, is 1.7 kilometres (1.1 mi) long, with a total lift of 16.5 meters (54 ft) at mid-tide
The artificial Miraflores Lake is the next stage, 1.7 kilometers (1.0 mi) long, and 16.5 metres (54 ft) above sea level
The single-stage Pedro Miguel lock, which is 1.4 kilometres (0.8 mi) long, is the last part of the ascent with a lift of 9.5 meters (31 ft) up to the main level of the canal
The Gaillard (Culebra) Cut slices 12.6 kilometres (7.8 mi) through the continental divide at an altitude of 26 metres (85 ft), and passes under the Centennial Bridge
The Chagres River (Río Chagres), a natural waterway enhanced by the damming of Lake Gatún, runs west about 8.5 kilometres (5.3 mi), merging into Lake Gatun
Gatun Lake, an artificial lake formed by the building of the Gatun Dam, carries vessels 24.2 kilometers (15.0 mi) across the isthmus
The Gatún locks, a three-stage flight of locks 1.9 kilometres (1.2 mi) long, drop ships back down to sea level
A 3.2 kilometer (2.0 mi) channel forms the approach to the locks from the Atlantic side
Limón Bay (Bahía Limón), a huge natural harbour, provides an anchorage for some ships awaiting transit, and runs 8.7 kilometers (5.4 mi) to the outer breakwater
Petronas Towers, twin skyscrapers in Kuala Lumpur, Malaysia, that are the world's tallest twin towers. Standing 1,483 ft (452 m) high, they were designed by the Argentinean-American architect Cesar Pelli. Completed in 1997, they surpassed Chicago's Sears Tower as the record-holding tallest structure; they themselves were surpassed by Taipei 101 in 2003. The twin towers house Petronas, Malaysia's government-owned oil company, as well as associated Malaysian firms and multinational companies. Part of a large burst of construction that marked the country's 1990s economic boom, the buildings stand at the northern end of a projected high-tech business zone, the Malaysia Multimedia Supercorridor. Built of steel-reinforced concrete columns clad in stainless steel and glass, with a design based on geometric patterns originating in ancient Islam, the 88-story buildings are connected at levels 41 and 42 by a double-decker pedestrian skybridge, and each tower is surmounted by a 242-ft-high (74-m) pinnacle. At the lower level, the Petronas Towers also include a concert hall that is home to the Malaysian Philharmonic and a business reference library.
