Recent content by Mapes

I've used both Cr and Ti as an adhesion layer for Au to Si. The Ti was used in the context of an implantable medical device—Ti was perceived to be more biocompatible. One factor is that the adhesion layer inevitably diffuses somewhat into the Au, especially at higher temperatures, which can...

As always, thank you Chester! Edited to fix. And the reason I should have caught that is that the curves of the Gibbs free energy have an increasingly negative slope with increasing temperature. And when drawn correctly, they end up at T = 0 K as a straight flat line, because the entropy and...

And how! Material properties are second derivatives of thermodynamic potentials. For example, the thermal expansion coefficient is $$\alpha_V=\frac{1}{V}\left(\frac{\partial V}{\partial T}\right)=\frac{1}{V}\left(\frac{\partial^2 G}{\partial T\partial P}\right)$$ The stiffness is...

Fluids have zero shear modulus, so fluid flow can be driven by an arbitrarily small shear stress. In this way, the shear modulus (or lack thereof) does define fluids, and the flow of fluids is indeed "related" to the shear modulus. But the question is vague. The bulk compressibility also...

Experimentalists have also looked at the size of a drop as it falls (e.g., the pendant-drop approach, J Tille and J C Kelly 1963 Br. J. Appl. Phys. 14 717), the maximum bubble pressure method, electrostatic levitation of oscillating droplets, and characterization of oscillating droplets in...

Have you read Compton et al.'s "Graphene Oxide, Highly Reduced Graphene Oxide, and Graphene: Versatile Building Blocks for Carbon-Based Materials"?

Sure, you can split up any object and make free-body diagrams of the components. From the free-body diagrams, you can find (for example) the torque on a uniform part of the composite beam and thus the shear stress in the thin wall.

Regarding the perceived asymmetry between heating things up vs. cooling them down, note that we're surrounded by sources of low-entropy, non-thermal energy that are specifically intended to drive irreversible processes, which always produce heat. Some examples are batteries, electrical wall...

Have you been given an empirical equation such as the one in Table 6-1-2 here? In this case, by plugging in the numbers, the stress concentration factor would be 2.23, and the nominal stress would therefore be 16.12. But this is just an empirical fit, of course.

It might be more precise to say a very small difference in the amount of opposing force, or, better still, a nearly equal opposing force. Zero opposing force would maximize reversibility because it would maximize the gradient driving the reaction.

Please see the discussion of the correlation between stiffness, melting temperature, and thermal expansion here. You can investigate the correlation using Wolfram Alpha and verify that for the chemical elements, for example, the correlations exist but are not perfect.

Whenever energy transfer is driven by a gradient (e.g., a pressure difference causing a change in volume, a voltage difference causing electric charge transfer, or a temperature difference that heats something up), entropy is produced and reversibility is violated. In contrast, steep gradients...

A reversible process doesn't increase entropy and thus cannot exist in the real world (although we can come arbitrarily close). Every real process is irreversible. You can generally slow down a process as much as you wish to satisfy your criterion for "quasi-static". Another simple example to...

Your third equation (which would be more clearly written ##V\,dp=-p\,dV##) already assumes constant temperature, right? Otherwise, I don't know how you're getting it. Also, your first equation for Gibbs free energy is incorrect; you've mixed up ##T## and ##S##.

##F## being constant is only one prerequisite to be a minimum; you also need to show that the second derivative is less than zero.