Transport
[right]Aspects of transport
The field of transport has several aspects: loosely they can be divided into a triad of infrastructure, vehicles, and operations. Infrastructure includes the transport networks (roads, railways, airways, waterways, canals, pipelines, etc.) that are used, as well as the nodes or terminals (such as airports, railway stations, bus stations and seaports). The vehicles generally ride on the networks, such as automobiles, bicycles, buses, trains, aircraft. The operations deal with the way the vehicles are operated on the network and the procedures set for this purpose including the legal environment (Laws, Codes, Regulations, etc.) Policies, such as how to finance the system (for example, the use of tolls or gasoline taxes) may be considered part of the operations.
Broadly speaking, the design of networks are the world's future. Domains of civil engineering and urban planning, the design of vehicles of mechanical engineering and specialized subfields such as nautical engineering and aerospace engineering, and the operations are usually specialized, though might appropriately belong to operations research or systems engineering.
[edit] Modes and categories
Main article: Mode of transport
Modes are combinations of networks, vehicles, and operations, and include walking, the road transport system, rail transport, ship transport and modern aviation.
Air transport
Cable transport
Conveyor transport
Human-powered transport
Hybrid transport
New Mobility Agenda
Rail transport
Road transport, including human-powered transport such as walking and cycling
Ship transport
Space transport
Sustainable transportation
Transport on other planets
Proposed future transport
[edit] Animal-powered transport
Animal-powered transport is a broad category of the human use of non-human working animals (also known as "beasts of burden") for the movement of people and goods. Humans may ride some of the larger of these animals directly, use them as pack animals for carrying goods, or harness them, singly or in teams, to pull (or haul) sleds or wheeled vehicles.
[edit] Air transport
Main article: Air transport
A fixed-wing aircraft, commonly called airplane or aeroplane, is a heavier-than-air craft where movement of the wings in relation to the aircraft is not used to generate lift. The term is used to distinguish from rotary-wing aircraft, where the movement of the lift surfaces relative to the aircraft generates lift. A more rare type of aircraft that is neither fixed-wing nor rotary-wing is an ornithopter. A heliplane is both fixed-wing and rotary-wing.
A Cessna 177 propeller-driven general aviation aircraftFixed-wing aircraft include a large range of craft from small trainers and recreational aircraft to large airliners and military cargo aircraft. Some aircraft use fixed wings to provide lift only part of the time and may or may not be referred to as fixed-wing.
The current term also embraces aircraft with folding the wings that are intended to fold when on the ground. This is usually to ease storage or facilitate transport on, for example, a vehicle trailer or the powered lift connecting the hangar deck of an aircraft carrier to its flight deck. It also embraces aircraft, such as the General Dynamics F-111, Grumman F-14 Tomcat and the Panavia Tornado, which can vary the sweep angle of their wings during flight. These aircraft are termed "variable geometry" aircraft. When the wings of these aircraft are fully swept, usually for high speed cruise, the trailing edges of their wings about the leading edges of their tailplanes, giving an impression of a single delta wing if viewed in plan. There are also rare examples of aircraft which can vary the angle of incidence of their wings in flight, such the F-8 Crusader, which are also considered to be "fixed-wing".
Two necessities for all fixed-wing aircraft (as well as rotary-wing aircraft) are air flow over the wings for lifting of the aircraft, and an open area for landing. The majority of aircraft, however, also need an airport with the infrastructure to receive maintenance, restocking, refueling and for the loading and unloading of crew, cargo and/or passengers. While the vast majority of aircraft land and take off on land, some are capable of take off and landing on ice, snow and calm water.
The aircraft is the second fastest method of transport, after the rocket. Commercial jet aircraft can reach up to 875 km/h. Single-engine aircraft are capable of reaching 175 km/h or more at cruise speed. Supersonic aircraft (military, research and a few private aircraft) can reach speeds faster than sound. The record is currently held by the SR-71 with a speed of 3,529.56 km/h (2193.17 mph, 1905.81 knots).[1]
[edit] Rail
Main article: Rail transport
Rail transport is the transport of passengers and goods along railways or railroads. A typical railway (or railroad) track consists of two parallel steel (or in older networks, iron) rails, generally anchored perpendicular to beams (termed sleepers or ties) of timber, concrete, or steel to maintain a consistent distance apart, or gauge. The rails and perpendicular beams are usually then placed on a foundation made of concrete or compressed earth and gravel in a bed of ballast to prevent the track from buckling (bending out of its original configuration) as the ground settles over time beneath and under the weight of the vehicles passing above. The vehicles traveling on the rails are arranged in a train; a series of individual powered or unpowered vehicles linked together, displaying markers. These vehicles (referred to, in general, as cars, carriages or wagons) move with much less friction than on rubber tires on a paved road, and the locomotive that pulls the train tends to use energy far more efficiently as a result.
Acela Express, an American high-speed passenger trainIn rail transport, a train consists of rail vehicles that move along guides to transport freight or passengers from one place to another. The guideway (permanent way) usually consists of conventional rail tracks, but might also be monorail or maglev. Propulsion for the train is provided by a separate locomotive, or from individual motors in self-propelled multiple units. Most trains are powered by diesel engines or by electricity supplied by trackside systems. Historically the steam engine was the dominant form of locomotive power through the mid-20th century, but other sources of power (such as horses, rope (or wire), gravity, pneumatics, or gas turbines) are possible.
[edit] Road transport
Main article: Road transport
[edit] Automobile
An automobile is a wheeled passenger vehicle that carries its own motor. Different types of automobiles include cars, buses, trucks, and vans. Some include motorcycles in the category, but cars are the most typical automobiles. As of 2002 there were 590 million passenger cars worldwide (roughly one car for every ten people), of which 170 million in the U.S. (roughly one car for every two people) [1].
The automobile was thought of as an environmental improvement over horses when it was first introduced in the 1890s. Before its introduction, in New York City alone, more than 1,800 tons of manure had to be removed from the streets daily, although the manure was used as natural fertilizer for crops and to build top soil. In 2006, the automobile is recognized as one of the primary sources of world-wide air pollution and a cause of substantial noise pollution and adverse health effects.
[edit] See also
Bicycle
Bus
Carpooling
Cycling
Human-powered transport
Limousine
Road train
Share taxi
Semi-trailer truck
Taxicab
Truck
[edit] Water transport
Main article: Ship transport
[edit] Watercraft
A watercraft is a vehicle designed to float on and move across (or under) water. The need for buoyancy unites watercraft, and makes the hull a dominant aspect of its construction, maintenance, and appearance.
Most watercraft would be described as either ships or boats; although nearly all ships are larger than nearly all boats, the distinction between those two categories is not one of size per se.
A rule of thumb says "a boat can fit on a ship, but a ship can't fit on a boat", and a ship usually has sufficient size to carry its own boats, such as lifeboats, dinghies, or runabouts.
Often local law and regulation will define the exact size (or the number of masts) that distinguishes a ship from boats.
Traditionally submarines, being small, were called "boats"; in contrast, nuclear-powered submarines' are large, much roomier, and classed as ships.
Another definition says a ship is any floating craft that transports cargo for the purpose of earning revenue; in that context, passenger ships transport "supercargo", another name for passengers or persons not working on board. However, neither fishing boats nor ferries are considered ships, though both carry cargo (their catch of the day or passengers) and lifeboats.
English seldom uses the term watercraft to describe any specific individual object (and probably then only as an affectation): rather the term serves to unify the category that ranges from small boats to the largest ships, and also includes the diverse watercraft for which some term even more specific than ship or boat (e.g., canoe, kayak, raft, barge, jet ski) comes to mind first. (Some of these would even be considered at best questionable as examples of boats.)
[edit] Ship transport
Ship transport is the process of moving people, goods, etc. by barge, boat, ship or sailboat over a sea, ocean, lake, canal or river. This is frequently undertaken for purposes of commerce, recreation or military objectives.
A hybrid of ship transport and road transport is the historic horse-drawn boat. Hybrids of ship transport and air transport are kite surfing and parasailing.
The first craft were probably types of canoes cut out from tree trunks. The colonization of Australia by Indigenous Australians provides indirect but conclusive evidence for the latest date for the invention of ocean-going craft; land bridges linked southeast Asia through most of the Malay Archipelago but a strait had to be crossed to arrive at New Guinea, which was then linked to Australia. Ocean-going craft were required for the colonization to happen.
Early sea transport was accomplished with ships that were either rowed or used the wind for propulsion, and often, in earlier times with smaller vessels, a combination of the two.
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الجمعة مارس 21, 2008 4:01 pm
