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5/22/2018 Physics Heat
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C C
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http://www.except.nl/en/#.en.articles.92-led-artificial-light-guide
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http://www.lbl.gov/Science-Articles/Archive/sb/Aug-
2004/colored_materials.jpg
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)TT(
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initial
initialfinal=
M .
coefficient ofthermal expansion (1/K or 1/C)
Tinit
TfinalLfinal
Linit
I
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I DEEND ON HE CAL CE
+ .
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A
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E
http://en.wikipedia.org/wiki/Expansion_joint
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H M (2009)
http://www.telegraph.co.uk/news/picturegalleries/worldnews/4360255/Heatwave-in-
Melbourne-plays-havoc-with-the-Australian-Open.html
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http://www.hydroone.com/OurCommitment/Environment/Pages/Vegetation.aspx
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Source: Conceptual Physics (9th edition) by Paul Hewitt
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http://biology200.gsu.edu/houghton/2107%20%2713/lecture15.html
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Source: Conceptual Physics (9th edition) by Paul Hewitt
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C C A
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Polypropylene 145-180
Polyethylene 106-198Polystyrene 90-150Teflon 126-216
Polymersat room Temp.
Ceramics
Magnesia (MgO) 13.5Alumina (Al2O3) 7.6Soda-lime glass 9Silica (cryst. SiO2) 0.4
MetalsAluminum 23.6Steel 12Tungsten 4.5Gold 14.2
(10-6/K)Material
Selected values from Table 19.1, Callister 7e.
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.
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.
heat capacity(J/mol-C)
energy input (J/mol)
temperature change (K)dT
dQC =
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A
A
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http://www.mcdonalds.co.uk/ukhome/product_nutrition.dessertstreats.108.apple-pie.html
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https://www.brisbanehotairballooning.com.au/faqs/exam-help/140-sea-land-breezes.html
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https://www.brisbanehotairballooning.com.au/faqs/exam-help/140-sea-land-breezes.html
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incr
easing
cp
Selected values from Table 19.1, Callister 7e.
PolymersPolypropylenePolyethylenePolystyreneTeflon
cp(J/kg-K)
at room T
CeramicsMagnesia (MgO)Alumina (Al2O3)
Glass
MetalsAluminumSteelTungstenGold
1925185011701050
900486138128
material
940775
840
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.
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, .
,
.
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dxdTkq =
D: .:
temperature
gradient
thermal conductivity (J/m-K-s)
heat flux(J/m2-s)
T2 > T1T1
x1 x2heat flux
Fouriers Law
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Hot end Cold end
heat
Molecules at the hot end of a rod vibrate faster and faster as thetemperature increases. When these molecules collide with their lessenergetic neighbors, some kinetic energy is transferred to them. Throughsuch molecular collisions, energy travels down the rod.
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H , !
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C !
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http://www.swanshurst.org/documents/none/22199__2._heat_loss_and_insulation_v2.0.ppt
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http://en.wikipedia.org/wiki/File:AMD_heatsink_and_fan.jpg
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increasing
k
Polymers
Polypropylene 0.12Polyethylene 0.46-0.50Polystyrene 0.13Teflon 0.25
By vibration/rotation of chainmolecules
CeramicsMagnesia (MgO) 38Alumina (Al2O3) 39Soda-lime glass 1.7Silica (cryst. SiO2) 1.4
By vibration ofatoms
MetalsAluminum 247
Steel 52Tungsten 178Gold 315
By vibration of
atoms andmotion ofelectrons
k (W/m-K) Energy TransferMaterial
Selected values from Table 19.1,Callister 7e
.
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Space Shuttle Orbiter
Silica tiles (400-1260C):--large scale application --microstructure:
Fig. 19.2W, Callister 6e. (Fig. 19.2W adapted from L.J.Korb, C.A. Morant, R.M. Calland, and C.S. Thatcher, "TheShuttle Orbiter Thermal Protection System", CeramicBulletin
, No. 11, Nov. 1981, p. 1189.)
Fig. 19.3W, Callister 5e. (Fig. 19.3W courtesy theNational Aeronautics and Space Administration.)
Fig. 19.4W, Callister 5e. (Fig. 219.4W courtesyLockheed Aerospace CeramicsSystems, Sunnyvale, CA.)
reinf C-C(1650C)
Re-entry TDistribution
silica tiles(400-1260C)
nylon felt, silicon rubbercoating (400C)
~90% porosity!Si fibers
bonded to oneanother duringheat treatment.
100m
Chapter-opening photograph, Chapter 23, Callister 5e(courtesy of the National Aeronautics and SpaceAdministration.)
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C, J. (2005) M E: A
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