A steam engine is a heat engine that performs mechanical
work using steam as its working fluid.
Steam engines are external combustion engines, where the
working fluid is separate from the combustion products. Non-combustion heat
sources such as solar power, nuclear power or geothermal energy may be used.
The ideal thermodynamic cycle used to analyze this process is called the
Rankine cycle. In the cycle, water is heated and transforms into steam within a
boiler operating at a high pressure. When expanded through pistons or turbines,
mechanical work is done. The reduced-pressure steam is then condensed and
pumped back into the boiler.
In general usage, the term steam engine can refer to either
the integrated steam plants (including boilers etc.) such as railway steam
locomotives and portable engines, or may refer to the piston or turbine
machinery alone, as in the beam engine and stationary steam engine. Specialized
devices such as steam hammers and steam pile drivers are dependent on the steam
pressure supplied from a separate boiler.
Using boiling water to produce mechanical motion goes back
over 2000 years, but early devices were not practical. The Spanish inventor Geronimo
de Ayanz y Beaumont obtained the first patent for a steam engine in 1606. In
1698 Thomas Savery patented a steam pump that used steam in direct contact with
the water being pumped. Savery's steam pump used condensing steam to create a
vacuum and draw water into a chamber, and then applied pressurized steam to
further pump the water. Thomas Newcomen's atmospheric engine was the first
commercial true steam engine using a piston, and was used in 1712 for pumping
in a mine.
In 1781 James Watt patented a steam engine that produced
continuous rotary motion. Watt's ten-horsepower engines enabled a wide range of
manufacturing machinery to be powered. The engines could be sited anywhere that
water and coal or wood fuel could be obtained. By 1883, engines that could
provide 10,000 hp had become feasible. The stationary steam engine was a key
component of the Industrial Revolution, allowing factories to locate where
water power was unavailable. The atmospheric engines of Newcomen and Watt were
large compared to the amount of power they produced, but high pressure steam
engines were light enough to be applied to vehicles such as traction engines
and the railway locomotives.
Reciprocating piston type steam engines remained the
dominant source of power until the early 20th century, when advances in the design
of electric motors and internal combustion engines gradually resulted in the
replacement of reciprocating (piston) steam engines in commercial usage, and
the ascendancy of steam turbines in power generation. Considering that the
great majority of worldwide electric generation is produced by turbine type
steam engines, the "steam age" is continuing with energy levels far
be.
A computer is a
general purpose device that can be programmed to carry out a set of arithmetic
or logical operations automatically. Since a sequence of operations can be readily
changed, the computer can solve more than one kind of problem.
Conventionally, a computer consists of at least one
processing element, typically a central processing unit (CPU), and some form of
memory. The processing element carries out arithmetic and logic operations, and
a sequencing and control unit can change the order of operations in response to
stored information. Peripheral devices allow information to be retrieved from
an external source, and the result of operations saved and retrieved.be yond
those of the turn of the 19th century.
Devices have been used to aid computation for thousands of
years, mostly using one-to-one correspondence with fingers. The earliest
counting device was probably a form of tally stick. Later record keeping aids
throughout the Fertile Crescent included calculi (clay spheres, cones, etc.)
which represented counts of items, probably livestock or grains, sealed in
hollow unbaked clay containers. The use of counting rods is one example. Purely
electronic circuit elements soon replaced their mechanical and
electromechanical equivalents, at the same time that digital calculation replaced
analog. The engineer Tommy Flowers, working at the Post Office Research Station
in London in the 1930s, began to explore the possible use of electronics for
the telephone exchange. Experimental equipment that he built in 1934 went into
operation 5 years later, converting a portion of the telephone exchange network
into an electronic data processing system, using thousands of vacuum tubes. In
the US, John Vincent Atanasoff and Clifford E. Berry of Iowa State University
developed and tested the Atanasoff–Berry Computer (ABC) in 1942, the first
"automatic electronic digital computer". This design was also
all-electronic and used about 300 vacuum tubes, with capacitors fixed in a
mechanically rotating drum for memory.
bibliography
Palermo, By Elizabeth. "Who Invented the Steam Engine?" LiveScience. TechMedia Network, 2014. Web. 01 Apr. 2016.
"A Brief History Of Computers That Changed The World." MakeUseOf. Web. 01 Apr. 2016.