Questions tagged [thermal-conductivity]

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Modelling heat generation of a lithium sulfur battery [closed]

Hi I was wondering how to model the heat generation of a lithium sulfur battery during the charge and discharge. How would I find the Thermal model equation, Equation for heat balance for a ltihium ...
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12 views

Difference in collision cross-section obtained by measurement method

I have a simple question of Physical Chemistry, but I don't know the answer. We can find collision cross-section(σ) through experiments in three ways. first, diffusion flux experiment. diffusion ...
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110 views

Is there an exothermic reaction when washing hands with water and hand sanitiser?

I accidentally washed my hands with water (cold/lukewarm) and hand sanitiser alcohol (room temperature) instead of soap. I felt like my hands have gotten warmer when I applied it. Only using alcohol ...
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1answer
198 views

Electrical and Thermal conductivity of electrum alloys

I have tried to search for this to little effect - I am trying to find electrical and thermal conductivity values for Electrum (a gold and silver alloy). Most sites mention the values depend on the ...
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1answer
54 views

VO2 unexpected conduction [closed]

$\ce{VO2}$ is a weird metal which becomes a conductor at temperatures higher than $\pu{67 ^\circ C}$, but below $\pu{67 ^\circ C}$, it is an insulator! How is this possible anyway? This is against ...
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180 views

Electrical and thermal conductivity of graphite

I was reading about carbon family where it was mentioned that electrical conductivity of graphite increases with temperature while thermal conductivity decreases. However, I could not find a suitable ...
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1answer
44 views

How would a temperature profile in wall change if the rate of heat transfer increases

Given the system below, how would the temperature profile in the wall change if the heat transfer in Fluid II was very fast? If the heat transfer in Fluid II is very fast, then the T-profile for $\ce{...
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65 views

Derive expression for average heat flux in heat exchanger

The single-tube heat exchanger is used to increase the temperature of fluid I from $T_{b1}$ to $T_{b2}$. The heating oil (fluid II) used for this task enters at temperature $T_{02}$ and leaves at ...
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32 views

Simplifying temperature profile

I am given the temperature profile below and the two equations: $$Q = (2\pi R_0)LU_0(T_{1\infty}-T_{2\infty})\tag1\label1$$ $$\frac{1}{U_0R_0} = \frac{1}{h_1R_0} +\frac{\ln(R_\mathrm a/R_0)}{k}+ ...
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1answer
101 views

Derive expression for heat flow from oil bath to metal sphere

A spherical ball of iron is put into a hot bath of oil. The iron ball is initially at a low temperature and heat transfer from the oil to the iron will increase the temperature of the iron ball. Use ...
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1answer
138 views

Temperature profile at steady state [closed]

Consider a solid wall consisting of three layers where the layers are of equal thickness but made out of different materials: $\ce{Layer 1}$ is made out of copper (high thermal conductivity), $\ce{...
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2answers
324 views

Determine heat flux from temperature profile

The heating element and the insulator are of equal thickness L. Heat transfer in the air film adjacent to the heater is assumed negligible. I've noticed that I find these type of problem the ...
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2answers
292 views

Pre-Hydrogen Feature On the Output Of a Gas Chromatography Thermal Conductivity Detector

A candidate for "dark matter", predicted and now apparently detected to have both a higher thermal conductivity and higher diffusion rate than H2 is purported in this PowerPoint Presentation file. ...
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2answers
207 views

Heat transfer through layered wall

An electrical heater is placed between two layers of insulation. The three layers (the heater and the two layers of insulation) have the same thickness. The figure below shows different temperature ...
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1answer
93 views

Equation for overall heat transfer coefficient

The heat flow (in $[\pu{J/s}]$) through the wall of a tube of length $L$ and inner radius $R_0$ is $$Q = (2πR_0L)U(T_{1\infty} - T_{2\infty}),$$ where $T_{1\infty}$ is the bulk temperature in the ...
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Graphite: Thermal and electrical conductivity

I recently encounter this question: Compare, while providing an explanation, the thermal and electrical conductivity of graphite to that of diamond. Provided answer: Graphite conducts electricity(...
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1k views

Why would a ~1 cm thick layer of argon be a significantly poorer conductor of heat than air?

In yesterday's new Periodic Video, Argon (new) - Periodic Table of Videos, after about 07 min 00 sec, Sir Martyn Poliakoff says: The final, and I have to admit perhaps slightly boring application of ...