Recent content by tony_engin

Using furnace and a rolling mill, how to strengthen these? (i)Commercially pure aluminium (ii) Fe-0.2%C (mild steel) (iii)Commercially pure Titanium (HCP metal; 2 methods can be used) How to strengthen these? For (i), is that just roll it and then normalise it? For(ii), forming...

Hi! How to relate the Young's Modulus with the coefficient of linear thermal expansion? It is known that they are inversely proportional to each other, but how to prove this?

Clausius2, SpaceTiger, Nylex, OlderDan, Really thank you for all your help! I think I get a clearer picture on this problem through the nice disscussion here. I will try to look at the problem later when I learn more about thermodynamics. Again, thank all of you!

um...heat is transferred from the gas to the surroudnings, so the entropy change by heat transfer of the gas should be -200/(273+40), and that of the surrounding is 200/273+25. And I don't mean that these two equals zero. I mean the entropy change of the gas alone equals zero since there is...

Um..as you have mentioned, there are two production of entropy geneartaoin..one from stirring the the gas and the other is the heat transfer. The former one probably would produce entropy and the latter one seems to pass entropy to the surrounding. So will the two effects just cancel out so...

I've moved this thread to the college homework zone.

Hi all! I'm a bit puzzled about this question. Is the entropy change of the ideal gas equals zero? And for the second part, is it equal to "Q/T" where Q=200kJ and T=40+273? I'm not sure about how to handle it...please help.

yes..attached is my "solution" to this problem.. please point out my faults..

Please kindly help...

Please kindly help

can anyone please help?

So, it should be "[(Asinx + Bcosx)x + C] exp(-2x)" or "x[Asinx + Bcosx + C] exp(-2x)"?

Hi all! Another problem I don't really know how to solve. I have the idea to prove that the entropy production would be negative in these cases, but I don't know how to do that...Could anyone please help?

Hi all! I'm a bit puzzled about this question. Is the entropy change of the ideal gas equals zero? And for the second part, is it equal to "Q/T" where Q=200kJ and T=40+273? I'm not sure about how to handle it...please help.

Hi all! For this question's part (a), I initially thought that I should first apply the first law for control volume for the system of the evaporator so that the rate of heat transfer from the evaporator to the air can be found. Then apply first law again on the air with using the specific heat...