Covers the study of (mostly homogeneous) macroscopic systems from a heat/energy/entropy point of view. Maybe combine with [tag:statistical-mechanics].

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Expressing thermal efficiency for a closed Brayton cycle in terms of static enthalpies

I have a Brayton cycle made of a compressor (stage 2 to 3), a heat exchanger (stage 3 to 4) and a turbine (stage 4 to 5). The turbine and compressor are connected through a shaft. The cycle is closed ...
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21 views

What are some good books on foundations of Thermodynamics [duplicate]

I am not looking for some introductory texts, graduate text, etc. I am looking for something that addresses to foundational problems in thermodynamics and statistical mechanics.
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What are the limitations of velocity selective coherent population trapping?

I'm somewhat familiar with limitations of Doppler cooling, particularly with the one photon recoil limit, but what I was curious about was what is the next barrier to cooling approaching absolute ...
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27 views

Calculate the change in entropy of superheated water [closed]

1 mole of superheated water at 110 degrees Celsius and 1atm is evaporated to a vapour at the same temperature. Find the change in entropy given that i) In the pressure range from 1atm to 1.4atm the ...
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1answer
24 views

Calculating Effects of Added Insulation on Rate of Temperature Change

I have recently begun tracking the temperature data available from my Nest thermostat. Among other things, the hope is to use this data to measure the effectiveness of additional insulation and other ...
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40 views

How to understand better this point of view on entropy?

On the book "Applied Differential Geometry" by William Burke we see a discussion about thermodynamics in which the following is said: A thermodynamic system is a homogeneous assembly that includes ...
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10 views

What would be a suitable textbook of first semester physical chemistry? [duplicate]

I am going to take PChem I in my biochem dept next sem, which is a watered down version of the PChem course in Chem dept. It basically covers thermodynamics and a little bit of quantum stuff. The ...
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33 views

What is the relation of particle velocity, temperature, and reaction activation energy

So, this curiosity has arisen for a fun project I thought I'd tackle, where I'm attempting create a crude simulation of an internal combustion cylinder. I wanted to explore the particle level ...
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39 views

Definition of emissivity?

A have come across a definition of emissivity which is along the following lines: Emissivity is the power emitted per solid angle per frequency per surface area. This definition, however seems ...
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32 views

How to integrate to find the view factor of two parallel disks of different radii? [closed]

You have two parallel coaxial disks of different radii. I have tables that give me the value as $$F_{ij} = \tfrac{1}{2} [S - \sqrt{S^2 - 4(r_j/r_i)^2}]$$ where $$S = 1 + \frac{1 + R_j^2}{R_i^2}$$ ...
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52 views

if copper is heated, does it become negatively charged?

i'm reading "Electronics for inventors" and there's this part where it says that free electrons never escape material due to electrostatic attraction with positive ions, but if heated, electrons are ...
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28 views

What are the implications of phase transition on electromagnetic device? [closed]

for the analysis of ferromagnetic materials on which I confirmed existence of Phase transition using Monte Carlo simulation implemented on Mat lab. contribution to knowledge are required.
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35 views

What is an extremal horizon?

In the contest of holography and thermodynamics, what is an extremal horizon? I am going through a paper by Hartnoll, Santos - Disordered Horizons: Holography of randomly disordered fixed points. They ...
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33 views

Plotting isothermals and adiabats

first time poster in this site. I am trying to create a small program to make a graph of the Carnot cycle. For isothermals I am simply trying to look for points where P*V would give the same ...
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1answer
86 views

$AdS_5$ Schwarzschild Black hole Temperature

This question is an extension of my previous Phys.SE question, but now in $AdS$ spacetime. I am attempting to derive the Temperature of the Schwarzschild solution in this space, which is given by: ...
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50 views

About Gibbs energy [closed]

In the Gibbs energy equation change in entropy is multiplied to temperature. But since entropy itself is energy exchange÷temperature. Then isn't entropy*temperature is equal to energy exchange. And ...
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79 views

my question is about gibbs energy, entropy and all that [closed]

I learnt that Gibbs energy is a free energy to do work! Tell me, what is this free energy and what is the work done (I mean what kind of work). Please also provide me an example of Gibbs free energy, ...
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1answer
44 views

Reconciling the Temperature and Pressure Relationship in Gasses vs Fluids

I've been trying to wrap my mind around this for the last couple of days to no avail. I suspect that much of my confusion comes from the fact that I have not yet taken a class specifically focused on ...
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75 views

Is work only a change of kinetic or potential energy?

I find out on the internet that work is a transfer of energy essentially kinetic. What is the use of work if it does not consider all the types of energy applied , i mean sometimes an objects internal ...
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41 views

Did the universe have a temperature during inflation?

I've heard it said that inflation was not an equilibrium process. But I've also heard it said that during inflation, the temperature of the universe was much cooler than before or after. If the ...
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66 views

A question about ultimate computation capability

If we consider the physical limit of computational capability of a system with average energy $E$, then (1) According to Margolus and Levitin, a quantum system with average energy $E$ takes time at ...
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47 views

The Ideal Gas Equation in higher dimensions

Basically I wanted to know whether or not the ideal gas equation, $PV=NkT$ would hold in higher dimensions? If so, how would you go about proving this? I can't see any reason as to why it shouldn't ...
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31 views

Deriving Boyle's law from only the Gay-Lussac laws

My physics professor during a lecture presumably mathematically derived Boyle's law from the two Gay-Lussac laws for ideal gasses. What he said is also printed in his own textbook. He states that, ...
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solar energy on a specific location

How to find the amount of solar wattage in any specific place on earh in a monthly manner? by solar wattage I mean the energy recieved from the sun in a squared meters.
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34 views

Thermodynamics of Rubik's cube

I was wondering... Could it be possible to calculate the entropy change while rearranging a Rubik's cube from a given arbitrary arrangement? I tried with 3*3*3=27 microstates...but achieved a pretty ...
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1answer
74 views

Is there a difference between solid-to-fluid convection and fluid-to-fluid convection?

I found an online calculator relating to convective heat transfer, but the calculator's description says it's for heat transfer between a solid surface and a moving fluid. However, the definitions ...
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Carnot cycle in steam processes

Our professor told us that in steam processes, such as Clausis-Rankine process, Carnot's cycle is impossible to achieve. Can someone explain why?
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dry adiabatic lapse rate

Adiabatic lapse rate is defined as $$ \Gamma_a \equiv -\left(\frac{dT}{dz}\right)_{\rm parcel}=-\frac{R_{\rm a} T}{c_p \,p}\left(\frac{dp}{dz}\right)_{\rm parcel} = \frac{g}{c_p} $$ $R_a$ is gas ...
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30 views

ferromagnetic and Curie temperature. Energy question

Is energy absorb and release back when a ferromagnetic material heats and cools passing through the Curie temperature?
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1answer
47 views

Methods to solve a vapor pressure equilibrium question with water on the moon? [closed]

"Imagine a tall column of water on the Moon, maintained at a temperature of 50°C and left to the open vacuum at the top. Up to what depth will the water continue to boil? The Moon's radius is 0.273 ...
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61 views

If a system has an internal energy equal to 0, does this mean it doesn't exist?

Enthalpy is a measure of energy in a thermodynamic system: It includes the internal energy, which is the energy required to create > a system, and the amount of energy required to make room for it ...
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32 views

Have we found a resolution to the Loschmidt paradox? [duplicate]

Loschmidt's Paradox (also known as the Reversibility Paradox) claims that it is not possible to deduce an irreversible process from time-symmetric dynamics such as the classic dynamics. This puts the ...
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1answer
32 views

Pressurized Tank with compressed air

How does ambient temperature affects the pressure of the tank filled with compressed air?
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124 views

Let's consider a sphere of radius $R$ at $T_0=100$ C in a far field of water with temperature $T_\infty=30$ C [closed]

Let's consider a sphere of radius $R$ at $T_0=100$ C in a far field of water with temperature $T_\infty=30$ C. How to calculate the sphere's temperature in each "layer" at any time? I really don't ...
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39 views

Different ways to calculate the bulk modulus

I am trying to calculate the bulk modulus of unit cells of materials with trigonal or monoclinic structure using two different methods: -The first one is by fitting the changes of volume and energy ...
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32 views

What role does enthalpy play when I am boiling pasta? [closed]

It has been a long time and I apologize about such a basic question. I always thought that the energy of the water, including the heat used to boil it, is important to boiling pasta. That is why the ...
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1answer
48 views

Why are $S = -k_B\sum_i P_i \ln P_i$ and $S = k_B \ln\Omega$ equivalent?

This might be a silly question, but I don't see the equivalence relation between these two equations. Could somebody explain to me how to derive one from the other? Thanks in advance!
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1answer
74 views

Maximum work obtained by mixing 2 gases

2 boxes containing the same number of moles of 2 ideal identical gases with the same adiabatic index (this is given as gamma), at the same initial temperature Ti but with different volumes, V1 and V2 ...
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82 views

Why should I discard a carafe if it has ever been heated empty? (Can thermal shock permanently weaken materials without causing them to fail?) [closed]

Related to "What pressure or tension occurs in a glass jar when I pour boiling water inside?" I just got a new coffeemaker, and one of the warnings in the manual states that you should discard the ...
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1answer
45 views

Does a movement of a solid in a liquid generate heat by friction?

We know that if we rubbed two solids, it generates heat. Also the shuttles coming into the atmosphere generates heat. So, likewise does a movement of a solid in a liquid generate heat? Also, what will ...
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23 views

Radiation collapse to black hole

I want to find the temperature at which radiation in AdS will collapse to form a black hole. I have even found a reference that gives the answer but I cannot understand it: ...
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1answer
56 views

Concept question about entropy of surroundings

By Clausius's definition $$dS_{surr} = \frac{\delta q_{rev}}{T}$$ but does this mean $$dS_{surr} = \frac{\delta q}{T}$$ where $\delta q$ is the infinitesimal heat absorbed by the surrounding in any ...
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why stack width is larger than the thermal and viscous penetration depth in thermoacoustic refrigerator?

The thermal and viscous penetration depth is smaller than the spacing in the stack:this assumption leads to the simplification of Rott‟s functions, where the complex hyperbolic tangents can be set ...
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38 views

Extra 5/2 tau term in chemical potential of a monoatomic ideal gas? [closed]

The chemical potential of an ideal monoatomic gas should be: $\mu = \tau ln \frac {n}{n_Q}$ http://web.mit.edu/ndhillon/www/Teaching/Physics/bookse5.html I get this result if I derive it using the ...
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1answer
44 views

thermodynamic generalized force and thermodynamic potential

I have stumbled across these and have taken some interest. Are the meanings of generalized "force" and "potential" the analogous to the case of mechanics where the derivative of one with respect to a ...
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40 views

Self-powered heat exchanger w/energy profit? [closed]

It is possible, considering the laws of physics, to build a heat exchanger that runs on the power it gathers from the environment? A typical heat exchanger uses less power to harvest heat for a ...
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30 views

Do we know how much energy is released in internal conversion (fluorescence)?

In the Jablonski Diagram, when photons hit a surface and certain frequencies are absorbed, then internal conversion occurs to the excited portions of the surface and energy is released as heat (If I ...
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28 views

Cooling of a surface due to fluid passing over it

I am working on a project that requires me to measure the cooling effect of a liquid flowing through a surface. In order for me to effectively calculate the cooling effect, the solution of the below ...
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34 views

Carnot cycle and entropy

From what I understand, in the Carnot cycle summing qi/Ti for each step results in zero, thus indicating a new state function, entropy = qrev/T. But since dE = 0 = q+w, then q = -w, and looking at the ...
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Doesn't this LED created by MIT violate the second law of thermodynamics?

Here is the article I am referring to: http://www.wired.co.uk/news/archive/2012-03/09/230-percent-efficient-leds In their own words (or at least the article writer's), "it appears to draw in heat ...