No old def.
.........
Ans.
Ceramics can be
broadly defined as nonmetallic inorganic solidsconsisting of infinite arrays of
metal and nonmetal ions. The arrays do not form discrete units such as molecules
or polymeric chains. As a rule, ceramics combine metal oxides, borides, carbides, arsenides, nitrides or other inorganic compounds into complex materials
which have properties that differ considerably from those of the original constituents.
The name “ceramic”
originates from the Greek word “keramos”, which means “pottery”. It
can also be traced back to the word“Shrapika” meaning “potter” in Sanskrit. For centuries,
ceramic materials were manufactured by firing clay precursors, and most of the
common ceramic products, such as tiles, cookware and bricks are still made this way.
Constantly growing
demand for advanced materials in the 20 th century resulted in
thedevelopment of new classes of ceramic materials that do not originate in
clays. Suchmaterials, known as “Advanced Ceramics”, are manufactured either
from pure metaloxides by ceramic forming techniques, or from other precursors
using sol-gel processing, atomic layer deposition,
or gas-phase synthesis. It wouldn’t be an
exaggeration to say that advanced ceramics play a crucial role in most
areas of modern science and technology. Their applications comprise
electronic materials and devices, nanomaterials, coatings, structuralmaterials
and composites.
Alternative energy is
an area where advanced ceramics have proven to be particularly valuable.
For example, high-temperature superconducting ceramic materials
demonstrategreat potential for reducing energy losses in electrical
systems and devices, thus increasing their energy efficiency. Thermoelectric
ceramics are capable of clean energy generationby transforming waste heat
into electricity. Highly porous complex oxide systems find useas
media for safe storage of energy rich gases such as hydrogen. Ceramics are also
usedas substrates for light emitting diodes, electrodes and electrolytes
for solid oxide fuel cells(SOFC), highly efficient insulators etc.
( Aldrich Chemistry, Material
Matters Advanced Ceramics, p.1)
2. Stochastic Control (Control Theory)
No old def.
......
Ans.
Stochastic control theory deals with dynamical systems, decribed by difference or differential equations, and subject to disturbances which are characterized as stochastic processes. The theory aims at answering problems of analysis and synthesis.
The tools required to solve all these problems are fairly recent developments. Stochastic control theory was used at M.I.T. during Second World War to synthesize fire control systems.
(Astrom K., Introduction to Stochastic Control Theory, p. 6)
3. Capacity Factor (Energy)
No old def.
........
Ans.
2. Stochastic Control (Control Theory)
No old def.
......
Ans.
Stochastic control theory deals with dynamical systems, decribed by difference or differential equations, and subject to disturbances which are characterized as stochastic processes. The theory aims at answering problems of analysis and synthesis.
- Analysis-What are statistical properties of system variables?
- Parametric Optimization-Suppose that we are given a system and a regulator with a given structure but with unknown parameters. How are the parameters to be adjusted in order to optimize the system with to a given criterion?
- Stochastic Optimal Control-Given a system and a criterion, find the control law which minimizes the criterion.
The tools required to solve all these problems are fairly recent developments. Stochastic control theory was used at M.I.T. during Second World War to synthesize fire control systems.
(Astrom K., Introduction to Stochastic Control Theory, p. 6)
3. Capacity Factor (Energy)
No old def.
........
Ans.
Definition:
Capacity factor is the ratio of the actual
energy produced in a given period, to the hypothetical maximum possible, i.e.
running full time at rated power.
Example:
Suppose you have a generator with a power
rating of 1500 kW. Hypothetically if it ran at full power for 24 hours a days
for 365 days, that would be:
(1500 kW) x (365 x 24 hours) = 13,140,000
kW-hr
in one year. Suppose that in fact it made
3,942,000 kWh in one year. Then in that year, the generator operated at a:
13,140,000 / 3,942,000 = 30%
capacity factor that year.
What
are common values for capacity factor?
All power plants have capacity factors, and
they vary depending on resource, technology, and purpose. Typical wind power
capacity factors are 20-40%. Hydro capacity factors may be in the range of
30-80%, with the US average toward the low end of that range. Photovoltaic
capacity factors in Massachusetts are 12-15%. Nuclear capacity factors are
usually in the range of 60% to over 100%, and the national average in 2002 was
92%. The capacity factors of thermal plants cover a wide range; base-loaded
thermal power plants (e.g. large coal) may often be in the range of 70-90%, and
a combined cycle gas plant might be 60% depending on gas prices, whereas power
plants in the role of serving peak power loads will be much lower. One might
expect a new biomass thermal plant to have an 80% capacity factor.
(Renewable Energy Research Laboratory
University of Massachusetts at Amherst, Wind
Power: Capacity
Factor, Intermittency, p. 1)
4. Crimping (about assembly) (joining)
Old def.
Crimping
Crimping involves the mechanical defotmation of the terminal barrel to form a permanent connection with the stripped end of a wire inserted into it.The crimping operation squeezes and closes the barrel around the bare wire.Crimping is performed by hand tools or crimping machines.The terminals are supplied either as individual pieces or on long strips that can be fed into a crimping machines.Properly accomplished, the crimped joint will have low electrical resistance and high mechanical strength.
(Fundamentals of Modern Manufacturing.Materials,processes and system 3rd edition, Mikell Groover, p. 850) 01.18
New, better
5.6 Crimping and Hemming
Crimping and hemming are similar processes in that both join metal or thermoplastic parts by plastically deforming one part over and/or into another part while they are in contact in order to cause interlocking. Both processes rely on one part conforming closely to the other. Parts are held together against unwanted movement by a combination of macroscopic (albeit sometimes small-scale) physical interference and friction from interlocking microscopic asperities being squeezed under a force from the elastic recovery component in the material used in the parts.
In crimping, an outer piece is crushed, squeezed, or otherwise plastically deformed around another to prevent subsequent relative movement between the two. To work, the outer part must be made from a material that is easily deformed, or, in some cases, a soft, malleable metal is sandwiched between the crimped and fixed parts to provide better compliance and result in more intimate contact. As an example, twisted or braided fine metal wires are commonly locked into a soft metal terminal connector by crimping the connector body down onto and around the wires for electrical assemblies.
...
Figure 5.11 schematically illustrates crimping and hemming plastic interlocks.
5. Boiler Feed Pump System (boiler pump)
Old def.
Boiler feed pump system:Many boiler feed pump system configurations have been used in power station applications.The basic system usually includes a deaerating and storage tank at some elevation above the suction of the boiler feed pump to provide a reservoir of heated deaerated condensate to the boiler feed pump and available suction head for the pump.The suction pipeline to the boiler feed pump is amply sized to maintain the required suction velocity into the boiler feed pump as well as limit the friction drop between a deaerator and the boiler feed pump.(Power Plant Engineering,Lawrence F. Drbal,Patricia G. Boston,Kayla L. Westra,p:341)
4. Crimping (about assembly) (joining)
Old def.
Crimping
Crimping involves the mechanical defotmation of the terminal barrel to form a permanent connection with the stripped end of a wire inserted into it.The crimping operation squeezes and closes the barrel around the bare wire.Crimping is performed by hand tools or crimping machines.The terminals are supplied either as individual pieces or on long strips that can be fed into a crimping machines.Properly accomplished, the crimped joint will have low electrical resistance and high mechanical strength.
(Fundamentals of Modern Manufacturing.Materials,processes and system 3rd edition, Mikell Groover, p. 850) 01.18
New, better
5.6 Crimping and Hemming
Crimping and hemming are similar processes in that both join metal or thermoplastic parts by plastically deforming one part over and/or into another part while they are in contact in order to cause interlocking. Both processes rely on one part conforming closely to the other. Parts are held together against unwanted movement by a combination of macroscopic (albeit sometimes small-scale) physical interference and friction from interlocking microscopic asperities being squeezed under a force from the elastic recovery component in the material used in the parts.
In crimping, an outer piece is crushed, squeezed, or otherwise plastically deformed around another to prevent subsequent relative movement between the two. To work, the outer part must be made from a material that is easily deformed, or, in some cases, a soft, malleable metal is sandwiched between the crimped and fixed parts to provide better compliance and result in more intimate contact. As an example, twisted or braided fine metal wires are commonly locked into a soft metal terminal connector by crimping the connector body down onto and around the wires for electrical assemblies.
...
Figure 5.11 schematically illustrates crimping and hemming plastic interlocks.
( Messler R., Integral Mechanical Attachment: A Resurgence of the Oldest Method of Joining, p.155-156)
5. Boiler Feed Pump System (boiler pump)
Old def.
Boiler feed pump system:Many boiler feed pump system configurations have been used in power station applications.The basic system usually includes a deaerating and storage tank at some elevation above the suction of the boiler feed pump to provide a reservoir of heated deaerated condensate to the boiler feed pump and available suction head for the pump.The suction pipeline to the boiler feed pump is amply sized to maintain the required suction velocity into the boiler feed pump as well as limit the friction drop between a deaerator and the boiler feed pump.(Power Plant Engineering,Lawrence F. Drbal,Patricia G. Boston,Kayla L. Westra,p:341)
New, better
Q. What is a boiler feed pump?
Ans. A pump that feeds boiler water (polished water) to the steam drum via the ecenomizer (for perheating)
Q. What are the most important criteria of a boiler feed pump?
Ans. It must be absolutely positive and reliable under all variable operating conditions.
Q. What kind of pump should a boiler feed pump be?
Ans. It may be
(a) a direct acting pump driven by its own cylinders
(b) a reciprocating pump driven by a motor or belted to the machinery
(c) a centrifugal pump, turbo driven or electrically driven by motor
(Chattopadhyay P., Boiler Operation Engineering: Questions and Answers, p.109)
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