T/K | Average energy / eV particle−1 | Average energy / kJ mole−1 |
---|---|---|
300 | 0.026 | 2.5 |
1000 | ||
1 | ||
300 |
T/K | Average energy /eV particle−1 | Average energy / kJ mole−1 |
---|---|---|
300 | 0.026 | 2.5 |
1000 | kT/e = 0.086 | 6.023 × 1023 × kT = 8.31 |
11600 | 1 | 6.023 × 1023 × kT = 96.4 |
36100 | kT/e = 3.11 | 300 |
Gradual | Accelerating | Sudden | ||
---|---|---|---|---|
Service | Opportunity | Electrical resistance thermometer | Heat-curable glues | Onset of ferro-electric properties |
Bimetal switches | Enhanced performance of detergents in hotter water | Can leave cooking to simmer | ||
A | B | C | ||
Challenge | Crazed glaze on crockery | High-temperature limit on semiconductor performance | Some permanent magnet materials demagnetise at modest temperatures | |
Need to compensate timer in clocks and watches | Excessive corrosion of high-temperature components | Water pipes burst through freezing | ||
D | E | F | ||
Process | Opportunity | Density variation provides convective mixing in castings | Temperature control of workability of glass | Chemical reaction selection by use of critical temperature |
Metal tyres and bearing sleeves can be shrink-fitted to wheels/shafts | Sintering of powders to continuous solid (a route to near net shape forming) | Melting allows casting processes | ||
G | H | I | ||
Challenge | Continuous welded railway lines may buckle in extreme heat or crack in extreme cold | Over-ageing of precipitation-hardened alloys | Upset metallurgy in the heat-affected zones of welds | |
Continued diffusion of previously implanted dopants in subsequent processing of microcircuit chips | Cracks in porcelain due to crystal transition in quartz | |||
J | K | L |
Material | α/10−6 K−1* | Material | α/10−6K−1* |
---|---|---|---|
Invar | 0.1 | nickel | 14 |
fused silica | 0.5 | stainless steel | 16 |
porcelain | 2 | copper | 17 |
brick | 7 | tin | 18 |
alumina | 8 | brass | 21 |
soda glass | 9 | aluminium | 24 |
steel | 11 | lead | 30 |
concrete | 12 | nylon | 100 |
Temperature, T | Curing time | Reaction rate, r | T −1 /K−1 | ln r | |
---|---|---|---|---|---|
/ °C | / K | / min | / min−1 | ||
142 | 415 | 6 | 0.17 | 0.00241 | −1.8 |
127 | 400 | 10 | 0.10 | 0.00250 | −2.3 |
100 | 373 | 30 | 0.033 | 0.00268 | −3.4 |
Temperature, T | Curing time | Reaction rate, r | T–1 I K–1 | ln r | |
---|---|---|---|---|---|
°C | K | / min | / min−1 | ||
20 | 293 | 1950 | 0.0005 | 0.00341 | −7.6 |
−15 | 25 | 27000 | 0.000037 | 0.00388 | −10.2 |
Phenomenon | Phase changes |
---|---|
Water boils at 100 °C | ………………………… |
NdFeB loses magnetisation above 450 °C | ………………………… |
Gold melts at 1063 °C | ………………………… |
Silver spontaneously oxidises below 1530 °C | A solid + a gas → another solid |
YBCO is superconducting below −180 °C | One solid → another solid |
Phenomenon | Phase changes |
---|---|
Water boils at 100 °C | Liquid (water) → gas (steam) |
NdFeB loses magnetisation above 450 °C | One (magnetic) solid → another (non-magnetic) solid |
Gold melts at 1063 °C | Solid → liquid |
Silver spontaneously oxidises below 1530 °C | A solid + a gas → another solid |
YBCO is superconducting below −180 °C | One solid → another solid |
if T < Tc, then property=subcritical value (or function) if T > Tc, then property=supercritical value (or function).
if T < 0 °C, then the 'natural' state of pure H2O will be ice.
if T= 100 °C then pure H2O may exist as water or steam.
Property | Value |
---|---|
Density / 103 kg m−3 | 6.45 |
Melting temperature / °C | 1240–1310 |
Resistivity / μΩ m | 0.82 ('high' phase), |
0.76 ('low' phase) | |
Ultimate tensile strength / MPa | 754–960 |
Typical elongation to fracture / % | 15.5 |
Typical yield strength / MPa | 560 ('high' phase), |
100 ('low' phase) | |
Approximate elastic modulus / GPa | 75 ('high' phase), |
28 ('low' phase) | |
Approximate Poisson's ratio | 0.3 |
Gradual | Accelerating | Sudden | ||
---|---|---|---|---|
Service | Opportunity | Electrical resistance thermometer | Heat-curable glues | Onset of ferro-electric properties |
Bimetal switches | Enhanced performance of detergents in hotter water | Can leave cooking to simmer | ||
A | B | C | ||
Challenge | Crazed glaze on crockery | High-temperature limit on semiconductor performance | Some permanent magnet materials demagnetise at modest temperatures | |
Need to compensate timer in clocks and watches | Excessive corrosion of high-temperature components | Water pipes burst through freezing | ||
D | E | F | ||
Process | Opportunity | Density variation provides convective mixing in castings | Temperature control of workability of glass | Chemical reaction selection by use of critical temperature |
Metal tyres and bearing sleeves can be shrink-fitted to wheels/shafts | Sintering of powders to continuous solid (a route to near net shape forming) | Melting allows casting processes | ||
G | H | I | ||
Challenge | Continuous welded railway lines may buckle in extreme heat or crack in extreme cold | Over-ageing of precipitation-hardened alloys | Upset metallurgy in the heat-affected zones of welds | |
Continued diffusion of previously implanted dopants in subsequent processing of microcircuit chips | Cracks in porcelain due to crystal transition in quartz | |||
J | K | L |
Accuracy | Reliability | Ruggedness | Cheapness | |
---|---|---|---|---|
Bimetallic | ||||
Gas capsule | ||||
Shape memory | ||||
Microphone | ||||
Metal resistance | ||||
Thermistor resistance |
Accuracy | Reliability | Ruggedness | Cheapness | Score (higher=better) | |
---|---|---|---|---|---|
Bimetallic | 1 | 3 | 3 | 3 | 10 |
Gas capsule | 1 | 2 | 2 | 2 | 7 |
Shape memory | 3 | 3 | 3 | 2 | 11 |
Microphone | 3 | 1 | 1 | 1 | 6 |
Metal resistance | 3 | 2 | 2 | 3 | 10 |
Thermistor resistance | 3 | 2 | 2 | 3 | 10 |