تاريخ التسجيل: Jan 2008
تقرير عن transport للصف العاشر
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For other uses, see Transport (disambiguation).
"Transportation" redirects here. For other uses, see Transportation (disambiguation).
The Ximen station, one of the stations of Metro Taipei.
The Mumbai-Pune Expressway in IndiaTransport or transportation is the movement of people and goods from one place to another. The term is derived from the Latin trans ("across") and portare ("to carry"). Industries which have the business of providing equipment, actual transport, transport of people or goods and services used in transport of goods or people make up a large broad and important sector of most national economies, and are collectively referred to as transport industries.
1 Aspects of transport
2 Modes and categories
2.1 (Non-human) animal-powered transport
2.2 Air transport
2.4 Road transport
2.4.2 See also
2.5 Water transport
2.5.2 Ship transport
18.104.22.168 See also
2.6 Intermodal transport
3 Transport and communications
4 Transport and land use
5 Transport in cities
5.1 See also
6 Transport, energy, and the environment
7.1 Some major research centres in Europe:
8 See also
 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 domain 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.
 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.
New Mobility Agenda
Road transport, including human-powered transport such as walking and cycling
Transport on other planets
Proposed future transport
 (Non-human) 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.
 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 $$$$ 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).
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.
 Road transport
Main article: Road transport
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) .
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.
 See also
 Water transport
Main article: Water transport
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, $$$$$$$-powered submarines' are large, much roomier, and classed as ships.
Another definition says a ship is any floating craft that transports cargo for the purpose of earning revenue; in that con$$$$, passenger ships transport "supercargo", another name for passengers or persons not working on board. However, neither fishing boats nor ferries are considered ships, though $$$$ 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.)
 Ship transport
Main article: 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.
Also there have been horse-powered boats, with horses on the deck providing power .
Ship transport was frequently used as a mechanism for conducting warfare. Military use of the seas and waterways is covered in greater detail under navy.
In the 1800s the first steam ships were developed, using a steam engine to drive a paddle wheel or propeller to move the ship. The steam was produced using wood or coal. Now most ships have an engine using a slightly refined type of petroleum called bunker fuel. Some specialized ships, such as submarines, use $$$$$$$ power to produce the steam.
Recreational or educational craft still use wind power, while some smaller craft use internal combustion engines to drive one or more propellers, or in the case of jet boats, an inboard water jet. In shallow draft areas, such as the Everglades, some craft, such as the hovercraft, are propelled by large pusher-prop fans.
Although relatively slow, modern sea transport is a highly effective method of transporting large quantities of non-perishable goods. Transport by water is significantly less costly than transport by air for trans-continental shipping.
In the con$$$$ of sea transport, a road is an anchorage.
 See also
Short sea shipping
 Intermodal transport
Main article: Intermodal transport
Intermodal freight transport refers to the combination of multiple types of transportation for a single shipment, for instance a shipment in a container may start on a truck in China, travel in a cargo ship over the Pacific Ocean to a port city in the U.S., then travel by train to the East Coast, finally being delivered by a truck.
 Transport and communications
Transport and communication are $$$$ substitutes and complements. Though it might be possible that sufficiently advanced communication could substitute for transport, one could telegraph, telephone, fax, or email a customer rather than visiting them in person, it has been found that those modes of communication in fact generate more total interactions, including interpersonal interactions. The growth in transport would be impossible without communication, which is vital for advanced transportation systems, from railroads which want to run trains in two directions on a single track, to air traffic control which requires knowing the location of aircraft in the sky. Thus, it has been found that the increase of one generally leads to more of the other.
 Transport and land use
The first Europeans who came to the New World brought with them a culture of transportation centred on the wheel. North America's Aboriginal peoples had developed differently, and moved through their country by means of canoes, kayaks, umiaks, coracles, and other water-borne vehicles, constructed from various types of bark, hide, bone, wood, and other materials; as well, the snowshoe, toboggan and sled were essential during the winter conditions that prevailed throughout the northern half of the continent for much of the year. Europeans quickly adopted all of these technologies themselves, and therefore were able to travel to the northern interior of Canada via the many waterways that branched out from the St. Lawrence River and from Hudson Bay.
There is a well-known relationship between the density of development, and types of transportation. Intensity of development is often measured by area of floor area ratio (FAR), the ratio of usable floorspace to area of land. As a rule of thumb, FARs of 1.5 or less are well suited to automobiles, those of six and above are well suited to trains. The range of densities from about two up to about four is not well served by conventional public or private transport. Many cities have grown into these densities, and are suffering traffic problems.
Land uses support activities. Those activities are spatially separated. People need transport to go from one to the other (from home to work to shop back to home for instance). Transport is a "derived demand," in that transport is unnecessary but for the activities pursued at the ends of trips. Good land use keeps common activities close (e.g. housing and food shopping), and places higher-density development closer to transportation lines and hubs. Poor land use concentrates activities (such as jobs) far from other destinations (such as housing and shopping).
There are economies of agglomeration. Beyond transportation some land uses are more efficient when clustered. Transportation facilities consume land, and in cities, pavement (devoted to streets and parking) can easily exceed 20 percent of the total land use. An efficient transport system can reduce land waste.
 Transport in cities
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Because of the much higher densities of people and activities, environmental, economic, public health, social and quality of life considerations and constraints are important in cities.
Urban transport has been led by professional transport planners and traffic experts, who have made use of the same forecasting and response tools that they have used to good effect in other transport sectors. This has led in most cities to a substantial overbuilding of the road and supporting infrastructure, which has maximized throughput in terms of the numbers of vehicles and the speeds with which they pass through and move around in the built-up areas.
Too much infrastructure and too much smoothing for maximum vehicle throughput means that in many cities there is too much traffic and many - if not all - of the negative impacts that come with it. It is only in recent years that traditional practices have started to be questioned in many places, and as a result of new types of analysis which bring in a much broader range of skills than those traditionally relied on – spanning such areas as environmental impact analysis, public health, sociologists as well as economists who increasingly are questioning the viability of the old mobility solutions. European cities are leading this transition.
 See also
New Mobility Agenda
 Transport, energy, and the environment
Main article: Global warming
Transport is a major use of energy, and transport burns most of the world's petroleum. Transportation accounts for 2/3 of all U.S. petroleum consumption.
The transportation sector generates 82 percent of carbon monoxide and 56 percent of NOx emissions and over one-quarter of total US greenhouse gas emissions. Hydrocarbon fuels also produces 15% of the carbon dioxide, a greenhouse gas widely thought to be the chief cause of global climate change, and petroleum-powered engines, especially inefficient ones, create air pollution, including nitrous oxides and particulates (soot). Although vehicles in developed countries have been getting cleaner because of environmental regulations, this has been offset by an increase in the number of vehicles and more use of each vehicle.
Indeed, transportation has the fastest growing carbon emissions of any economic sector.
By subsector, road transport is the largest contributor to global warming.
Other environmental impacts of transport systems include traffic congestion and automobile-oriented urban sprawl, which can consume natural habitat and agricultural lands.
Toxic runoff from roads and parking lots that can also pollute water supplies and aquatic ecosystems.
Alternative propulsion can reduce pollution. Low pollution fuels may have a reduced carbon $$$$$$$, and thereby contribute less in the way of carbon dioxide emissions, and generally have reduced sulfur, since sulfur exhaust is a cause of acid rain. The most popular low-pollution fuels at this time are biofuels: gasoline-ethanol blends and biodiesel. Hydrogen is an even lower-pollution fuel that produces no carbon dioxide, but producing and storing it economically is currently not feasible. Plug-in hybrids are energy-efficient vehicles that are going to be in the mass-production.
See also: Fuel efficiency in transportation
Another strategy is to make vehicles more efficient, which reduces pollution and waste by reducing the energy use. Electric vehicles use efficient electric motors, but their range is limited by either the extent of the electric transmission system or by the storage capacity of batteries. Electrified public transport generally uses overhead wires or third rails to transmit electricity to vehicles, and is used for $$$$ rail and bus transport. Battery electric vehicles store their electric fuel onboard in a battery pack. Another method is to generate energy using fuel cells, which may eventually be two to five times as efficient as the internal combustion engines currently used in most vehicles. Another effective method is to streamline ground vehicles, which spend up to 75% of their energy on air-resistance, and to reduce their weight. Regenerative braking is possible in all electric vehicles and recaptures the energy normally lost to braking, and is becoming common in rail vehicles. In internal combustion automobiles and buses, regenerative braking is not possible, unless electric vehicle components are also a part of the powertrain, these are called hybrid electric vehicles.
Shifting travel from automobiles to well-utilized public transport can reduce energy consumption and traffic congestion.
Walking and bicycling instead of traveling by motorized means also reduces the consumption of fossil fuels. While the use of these two modes generally declines as a given area becomes wealthier, there are some countries (including Denmark, Netherlands, Japan and parts of Germany, Finland and Belgium) where bicycling comprises a significant share of trips. Some cities with particularly high modal shares of cycling are Oulu (25%), Copenhagen (33%) and Groningen (50%). A number of other cities, including London, Paris, New York, Sydney, Bogotá, Chicago and San Francisco are creating networks of bicycle lanes and bicycle paths.
There is also a growing movement of drivers who practice ways to increase their MPG and save fuel through driving techniques. They are often referred to as hypermilers. Hypermilers have broken records of fuel efficiency, averaging 109 miles per gallon driving a Prius. In non-hybrid vehicles these techniques are also beneficial. Hypermiler Wanye Gerdes can get 59 MPG in a Honda Accord and 30 MPG in an Acura MDX.
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