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1answer
29 views

Calculating new temperature of an object when air temperature changes

I'm trying to calculate the new temperature of an object when the air temperature around it changes, given a period of time. Basically I get periodic readings from an air temperature sensor in a ...
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1answer
30 views

Spherical Shaped Electrical Leads for Thermal Conductivity Mitigation?

I am designing a thermionic converter and one of the biggest inefficiencies is the thermal conductivity and limited electrical conductivity of the leads. I'm trying to mitigate the loss of heat ...
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1answer
56 views

How to prove R value for insulation?

I ran some tests on different types of insulation. I heated water, and placed it into an insulated box. The temperature was recorded every minute, for the water, as well as the air. The insulation ...
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1answer
53 views

Heat flow in a hollow cylinder

Consider a hollow cylinder of different outer radius and inner radius and two different temperatures are maintained at the outer and inner surfaces such that inner temperature is higher. Because of ...
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1answer
586 views

Stress due to the mismatch of thermal expansion coefficients of two different attached materials

I'm simulating the thermo-electro-mechanical behavior of a copper wire which is surrounded by silicon dioxide. In other words, the wire segments is under mechanical and thermal loads and at the same ...
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1answer
367 views

Time constant of ice melt

I'm familiar with problems of "how much ice can you melt given some amount of energy", but I'm writing to get some clarification on the time constant of this event. This question might be somewhat ...
-2
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1answer
534 views

Why do phonons cause excellent heat conduction in diamonds?

Phonons are the quantum of lattice vibrations in crystals and are not to be confused with photons, the gauge bosons of the electromagnetic force. Apparently, they contribute to heat conduction, but I ...
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0answers
82 views

Is my method of calculating thermal conductivity of a metal wrong?

I am trying to determine the thermal conductivity of pure copper at various temperatures using the Weidemann-Franz Law but for some reason it is not matching up to textbook data. I used the Bloch ...
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0answers
63 views

In a non-degenerate plasma, why are e-e collision negligible compared to e-ion for thermal conduction?

I'm trying to make some order of magnitude estimates of heat transfer in stars - to better understand 1) why conduction is said to be negligible (for non-degenerate matter) and 2) when convection ...
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0answers
64 views

Thermal expansion of two bolts

I have this question asking me about the thermal expansions of two bolts, a steel one, and a brass one. I have the equation: $\ (\delta L/L)/T = \alpha $ I don't understand how I can use this ...
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0answers
65 views

Conduction– conservation of energy

So I know that conduction is transfer of thermal energy by direct contact via molecular collisions. For conduction, $Q/t$ is the rate of heat flow and is heat current ($I$). My textbook says that ...
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0answers
110 views

Thermal Conductivity Graph

This is our first time (as an engineer) seeing this type of graph that we can't interpret. This is a rough comparision of thermal conductivity from the Wiki page. ...
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0answers
26 views

Thermal Conduction through sphere

In general, a sphere with conductivity $\kappa$, heat capacity per unit volume $C$ and radius $R$ obeys the differential equation at time t: $$C\frac{\partial T}{\partial t} = \kappa \frac{\partial^2 ...
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27 views

Thermography time evolution

I have an imaging problem. I essentially have a metallic plate with a number of holes through it. I am looking at the number of holes with a thermal camera. While looking at the plate I have two ...
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0answers
101 views

Is the thermal time constant simply the heat capacity divided by thermal conductivity?

My professor gave me this temperature decay data to make an exponential fit and told me that the time constant tau should be heat capacity over thermal conductivity. I'm looking at the wikipedia page ...
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0answers
81 views

Calculate thermal conductance of thick walls of a cuboid, given material conductivity and cube size

Note 1: This is probably as much a maths question as physics. Note 2: I am not sure if my use of the the term conductance is correct. I want to make a kiln. The walls will be thick. I can come to ...
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0answers
50 views

Can we make any substance that will produce ions at low temprature

I am talking about thermal ionization, Is to possible to make any material or is there any element that can be ionized at let say 20 degree centigrade Temperature? I am a computer engineer and into ...