Thursday 27 February 2014

Electric car

From Wikipedia, the free encyclopedia

For hybrid cars, see Hybrid vehicle and Plug-in Hybrid.

Smart electric drive charging at an on-street station

Sustainable energy

Energy conservation
Cogeneration Energy efficiency Heat pump Green building Microgeneration Passive solar
Renewable energy
Anaerobic digestion Geothermal Hydroelectricity Solar Tidal Wind
Sustainable transport
Carbon-neutral fuel Electric vehicle Green vehicle Plug-in hybrid
Sustainable development portal Renewable energy portal Environment portal
v t e

An electric car is an automobile that is propelled by one electric motor or more, using electrical energy stored in batteries or another energy storage device. Electric motors give electric cars instant torque, creating strong and smooth acceleration.
The first electric cars appeared in the 1880s.^[1] Electric cars were popular in the late 19th century and early 20th century, until advances in internal combustion engine technology and mass production of cheaper gasoline vehicles led to a decline in the use of electric drive vehicles. The energy crises of the 1970s and 1980s brought a short-lived interest in electric cars; although, those cars did not reach the mass marketing stage, as is the case in the 21st century. Since 2008, a renaissance in electric vehicle manufacturing has occurred due to advances in battery and power management technologies, concerns about increasing oil prices, and the need to reduce greenhouse gas emissions.^[2]^[3] Several national and local governments have established tax credits, subsidies, and other incentives to promote the introduction and adoption in the mass market of new electric vehicles depending on battery size and their all-electric range.
Benefits of electric cars over conventional internal combustion engine automobiles include a significant reduction of local air pollution, as they do not emit tailpipe pollutants,^[4] in many cases, a large reduction in total greenhouse gas and other emissions (dependent on the fuel and technology used for electricity generation^[2]^[3]), and less dependence on foreign oil, which in several countries is cause for concern about vulnerability to oil price volatility and supply disruption.^[2]^[5]^[6] Widespread adoption of electric cars faces several hurdles and limitations, however, including the higher cost of electric vehicles, the lack of recharging infrastructure (other than home charging) and range anxiety, the driver's fear of the batteries running out of energy before reaching their destination due to the limited range of most existing electric cars.^[2]^[3]
As of January 2014, the number of mass production highway-capable all-electric passenger cars and utility vans available in the market is limited to about 25 models, mainly in the United States, Japan, Western European countries and China. Pure electric car sales in 2012 were led by Japan with a 28% market share of global sales, followed by the United States with a 26% share, China with 16%, France with 11%, and Norway with 7%.^[7] The world's top selling highway-capable electric car ever is the Nissan Leaf, released in December 2010 and sold in 35 countries, with global sales of 100,000 units by mid January 2014, representing a 45% market share of worldwide pure electric vehicles sold since 2010.^[8]^[9]

Practicing engineers

Belgian electrical engineers inspecting the rotor of a 40,000 kilowatt turbine of the General Electric Company in New York City

In most countries, a Bachelor's degree in engineering represents the first step towards professional certification and the degree program itself is certified by a professional body.^[55] After completing a certified degree program the engineer must satisfy a range of requirements (including work experience requirements) before being certified. Once certified the engineer is designated the title of Professional Engineer (in the United States, Canada and South Africa ), Chartered Engineer or Incorporated Engineer (in India, Pakistan, the United Kingdom, Ireland and Zimbabwe), Chartered Professional Engineer (in Australia and New Zealand) or European Engineer (in much of the European Union).
The advantages of certification vary depending upon location. For example, in the United States and Canada "only a licensed engineer may seal engineering work for public and private clients".^[56] This requirement is enforced by state and provincial legislation such as Quebec's Engineers Act.^[57] In other countries, no such legislation exists. Practically all certifying bodies maintain a code of ethics that they expect all members to abide by or risk expulsion.^[58] In this way these organizations play an important role in maintaining ethical standards for the profession. Even in jurisdictions where certification has little or no legal bearing on work, engineers are subject to contract law. In cases where an engineer's work fails he or she may be subject to the tort of negligence and, in extreme cases, the charge of criminal negligence. An engineer's work must also comply with numerous other rules and regulations such as building codes and legislation pertaining to environmental law.
Professional bodies of note for electrical engineers include the Institute of Electrical and Electronics Engineers (IEEE) and the Institution of Engineering and Technology (IET). The IEEE claims to produce 30% of the world's literature in electrical engineering, has over 360,000 members worldwide and holds over 3,000 conferences annually.^[59] The IET publishes 21 journals, has a worldwide membership of over 150,000, and claims to be the largest professional engineering society in Europe.^[60]^[61] Obsolescence of technical skills is a serious concern for electrical engineers. Membership and participation in technical societies, regular reviews of periodicals in the field and a habit of continued learning are therefore essential to maintaining proficiency. MIET(Member of the Institution of Engineering and Technology) is recognised in Europe as Electrical and computer (technology) engineer.^[62]
In Australia, Canada and the United States electrical engineers make up around 0.25% of the labor force (see note). Outside of Europe and North America, engineering graduates per-capita, and hence probably electrical engineering graduates also, are most numerous in Taiwan, Japan, and South Korea.[

Electronics

Main article: Electronic engineering

Electronic components

Electronic engineering involves the design and testing of electronic circuits that use the properties of components such as resistors, capacitors, inductors, diodes and transistors to achieve a particular functionality.^[22] The tuned circuit, which allows the user of a radio to filter out all but a single station, is just one example of such a circuit. Another example (of a pneumatic signal conditioner) is shown in the adjacent photograph.
Prior to the Second World War, the subject was commonly known as radio engineering and basically was restricted to aspects of communications and radar, commercial radio and early television.^[22] Later, in post war years, as consumer devices began to be developed, the field grew to include modern television, audio systems, computers and microprocessors. In the mid-to-late 1950s, the term radio engineering gradually gave way to the name electronic engineering.
Before the invention of the integrated circuit in 1959,^[26] electronic circuits were constructed from discrete components that could be manipulated by humans. These discrete circuits consumed much space and power and were limited in speed, although they are still common in some applications. By contrast, integrated circuits packed a large number—often millions—of tiny electrical components, mainly transistors,^[27] into a small chip around the size of a coin. This allowed for the powerful computers and other electronic devices we see today.

Microelectronics

Main article: Microelectronics

Microprocessor

Microelectronics engineering deals with the design and microfabrication of very small electronic circuit components for use in an integrated circuit or sometimes for use on their own as a general electronic component.^[28] The most common microelectronic components are semiconductor transistors, although all main electronic components (resistors, capacitors etc.)can be created at a microscopic level. Nanoelectronics is the further scaling of devices down to nanometer levels. Modern devices are already in the nanometer regime, with below 100 nm processing having been standard since about 2002.^[29]
Microelectronic components are created by chemically fabricating wafers of semiconductors such as silicon (at higher frequencies, compound semiconductors like gallium arsenide and indium phosphide) to obtain the desired transport of electronic charge and control of current. The field of microelectronics involves a significant amount of chemistry and material science and requires the electronic engineer working in the field to have a very good working knowledge of the effects of quantum mechanics.^[30]

Signal processing

Solid-state transistors

The invention of the transistor in late 1947 by William B. Shockley, John Bardeen, and Walter Brattain of the Bell Telephone Laboratories opened the door for more compact devices and led to the development of the integrated circuit in 1958 by Jack Kilby and independently in 1959 by Robert Noyce.^[19] Starting in 1968, Ted Hoff and a team at the Intel Corporation invented the first commercial microprocessor, which foreshadowed the personal computer. The Intel 4004 was a four-bit processor released in 1971, but in 1973 the Intel 8080, an eight-bit processor, made the first personal computer, the Altair 8800, possible.^[20]

Subdisciplines

Electrical engineering has many subdisciplines, the most popular of which are listed below. Although there are electrical engineers who focus exclusively on one of these subdisciplines, many deal with a combination of them. Sometimes certain fields, such as electronic engineering and computer engineering, are considered separate disciplines in their own right.

Power

Main article: Power engineering

Power pole

Power engineering deals with the generation, transmission and distribution of electricity as well as the design of a range of related devices.^[21] These include transformers, electric generators, electric motors, high voltage engineering, and power electronics. In many regions of the world, governments maintain an electrical network called a power grid that connects a variety of generators together with users of their energy. Users purchase electrical energy from the grid, avoiding the costly exercise of having to generate their own. Power engineers may work on the design and maintenance of the power grid as well as the power systems that connect to it.^[22] Such systems are called on-grid power systems and may supply the grid with additional power, draw power from the grid or do both. Power engineers may also work on systems that do not connect to the grid, called off-grid power systems, which in some cases are preferable to on-grid systems. The future includes Satellite controlled power systems, with feedback in real time to prevent power surges and prevent blackouts.

More modern developments

During the development of radio, many scientists and inventors contributed to radio technology and electronics. In his classic physics experiments of 1888, Heinrich Hertz transmitted radio waves with a spark-gap transmitter, and detected them by using simple electrical devices. The mathematical work of James Clerk Maxwell during the 1850s had shown the possibility of radio waves but Heinrich Hertz was the first to demonstrate their existence in 1888.

Guglielmo Marconi known for his pioneering work on long distance radio transmission

In 1897, Karl Ferdinand Braun introduced the cathode ray tube as part of an oscilloscope, a crucial enabling technology for electronic television.^[11] John Fleming invented the first radio tube, the diode, in 1904. Two years later, Robert von Lieben and Lee De Forest independently developed the amplifier tube, called the triode.^[12] In 1895, Guglielmo Marconi furthered the art of hertzian wireless methods. Early on, he sent wireless signals over a distance of one and a half miles. In December 1901, he sent wireless waves that were not affected by the curvature of the Earth. Marconi later transmitted the wireless signals across the Atlantic between Poldhu, Cornwall, and St. John's, Newfoundland, a distance of 2,100 miles (3,400 km).^[13] In 1920 Albert Hull developed the magnetron which would eventually lead to the development of the microwave oven in 1946 by Percy Spencer.^[14]^[15] In 1934 the British military began to make strides toward radar (which also uses the magnetron) under the direction of Dr Wimperis, culminating in the operation of the first radar station at Bawdsey in August 1936.^[16]
In 1941 Konrad Zuse presented the Z3, the world's first fully functional and programmable computer using electromechanical parts. In 1943 Tommy Flowers designed and built the Colossus, the world's first fully functional, electronic, digital and programmable computer.^[17] In 1946 the ENIAC (Electronic Numerical Integrator and Computer) of John Presper Eckert and John Mauchly followed, beginning the computing era. The arithmetic performance of these machines allowed engineers to develop completely new technologies and achieve new objectives, including the Apollo program which culminated in landing astronauts on the Moon.^[18]

19th century

However, it was not until the 19th century that research into the subject started to intensify. Notable developments in this century include the work of Georg Ohm, who in 1827 quantified the relationship between the electric current and potential difference in a conductor, Michael Faraday, the discoverer of electromagnetic induction in 1831, and James Clerk Maxwell, who in 1873 published a unified theory of electricity and magnetism in his treatise Electricity and Magnetism.^[3]
Beginning in the 1830s, efforts were made to apply electricity to practical use in the telegraph. By the end of the 19th century the world had been forever changed by the rapid communication made possible by engineering development of land-lines, submarine cables, and, from about 1890, wireless telegraphy.
Practical applications and advances in such fields created an increasing need for standardized units of measure. They led to the international standardization of the units volt, ampere, coulomb, ohm, farad, and henry. This was achieved at an international conference in Chicago 1893.^[4] The publication of these standards formed the basis of future advances in standardisation in various industries, and in many countries the definitions were immediately recognised in relevant legislation.^[5]

Thomas Edison built the world's first large-scale electrical supply network.

During these years, the study of electricity was largely considered to be a subfield of physics. It was not until about 1885 that universities and institutes of technology such as Massachusetts Institute of Technology (MIT) and Cornell University started to offer bachelor's degrees in electrical engineering. The Darmstadt University of Technology founded the first department of electrical engineering in the world in 1882. In that same year, under Professor Charles Cross at MIT began offering the first option of electrical engineering within its physics department.^[6] In 1883, Darmstadt University of Technology and Cornell University introduced the world's first bachelor's degree courses of study in electrical engineering, and in 1885 the University College London founded the first chair of electrical engineering in Great Britain.^[7] The University of Missouri established the first department of electrical engineering in the United States in 1886.^[8] Several other schools soon followed suit, including Cornell and the Georgia School of Technology in Atlanta, Georgia.
During these decades use of electrical engineering increased dramatically. In 1882, Thomas Edison switched on the world's first large-scale electric power network that provided 110 volts — direct current (DC) — to 59 customers on Manhattan Island in New York City. In 1884, Sir Charles Parsons invented the steam turbine. Turbines now provide the mechanical power for about 80 percent of the electric power in the world using a variety of heat sources. The alternating current power system developed rapidly after 1886 with efficient, practical, transformer and AC motor designs, including induction motors independently invented by Galileo Ferraris and Nikola Tesla and further developed into a practical three-phase form by Mikhail Dolivo-Dobrovolsky and Charles Eugene Lancelot Brown.^[9] AC had the ability to transmit power more efficiently over long distances via the use of transformers to increase and decrease voltages (not possible with DC). The spread in the use of AC set off what has been called the War of Currents between the backers of AC and DC based power systems, with AC being adopted as the overall standard.^[10]

Electrical engineering

From Wikipedia, the free encyclopedia

Electrical engineers design complex power systems...

...and electronic circuits.

Electrical engineering is a field of engineering that generally deals with the study and application of electricity, electronics, and electromagnetism. This field first became an identifiable occupation in the latter half of the 19th century after commercialization of the electric telegraph, the telephone, and electric power distribution and use. It now covers a wide range of subfields including electronics, digital computers, power engineering, telecommunications, control systems, RF engineering, and signal processing.
Electrical engineering may include electronic engineering. Where a distinction is made, usually outside of the United States, electrical engineering is considered to deal with the problems associated with systems such as electric power transmission and electrical machines, whereas electronic engineering deals with the study of electronic systems including computers, communication systems, integrated circuits, and radar.
From a different point-of-view, electrical engineers are usually concerned with using electricity to transmit electric power, while electronic engineers are concerned with using electricity to process information. The subdisciplines can overlap, for example, in the growth of power electronics, and the study of behavior of large electrical grids under the control of digital computers and electronics.

Sunday 23 February 2014

While much focus and discussion of the so-called "Big Data revolution" has been on the data itself and the exciting new applications it is enabling—from Google's self-driving cars through to CSIRO and University of Tasmania's better information systems for oyster farmers—less focus has been on the underpinning technologies and the talent driving these technologies.

Read more at: http://phys.org/news/2014-02-technologies-big.html#jCp

ശാസ്ത്ര സാങ്കേതിക മാർഗ്ഗങ്ങൾ ഉപയോഗിച്ച്, ഒരു നിശ്ചിത പ്രദേശത്തിന്റെ അന്തരീക്ഷസ്ഥിതി പ്രവചിക്കുന്ന പ്രക്രിയയാണ് കാലാവസ്ഥാ പ്രവചനം. സഹസ്രാബ്ദങ്ങളായി കാലാവസ്ഥാ പ്രവചനത്തിന് മനുഷ്യർ ശ്രമങ്ങൾ നടത്താറുണ്ടായിരുന്നു. ഇത്തരം പരിശ്രമത്തിന് ഒരു ശാസ്ത്രീയ രൂപം കൈവന്നത് പത്തൊൻപതാം നൂറ്റാണ്ടോട് കൂടിയാണ്. ഒരു പ്രദേശത്തിന്റെ കാലാവസ്ഥാ സംബന്ധമായ തത്സമയ പാരിമാണിക വിവരങ്ങൾ അപഗ്രഥിച്ചും, നിലവിലുള്ള അന്തരീക്ഷ പ്രക്രിയകളെ പറ്റിയുള്ള അറിവുകൾ ഉപയോഗിച്ച് ആ പ്രദേശത്തിനു വരാവുന്ന മാറ്റങ്ങൾ ഗണിച്ചറിഞ്ഞുമാണ് ഇന്ന് കാലാവസ്ഥാപ്രവചനം നടത്തുന്നത്.

New ideas and technology