Recent content by MisterX

This is an interesting question and I'd love to see someone knowledgeable chime in here. I wasn't able to find out, but I did find this table of target parameters they have for the Nb3Sn type II superconducting wire for HE-LHC. It's mentioned in this paper from about 2 years ago that "the...

That is interesting. I was not aware of these production limitations. I was aware of various demonstration projects from over a decade ago which were a few hundred meters in size. One is quoted as employing 155,000 meters of wire [1]. A this is still 2 orders of magnitude shorter than the...

or perhaps a different publicly funded effort - ITER is already obsolete due to advances in superconductor technology that has happened during its very slow schedule. Now high temperature superconducting (HTS) wire permits construction of a more cost effective tokomak with higher fields. One...

A number of satellites failed due to problems with the reaction wheel systems which help control attitude. It has been proposed that this may be due to solar radiation causing arcing in the bearings. A newly discovered branch of the fault tree explaining systemic reaction wheel failures and...

The premise of the question is potentially flawed. First we must ask, will oil (or other fossil fuels) run low? The answer seems to be no. There are more fossil fuels than we can exploit without serious, potentially fatal environmental damage.[1] We will have other problems before it happens, to...

Yes, in general angular momentum can depend on the location of the origin. This could be seen as well just by considering what happens to the angular momentum of a point mass when you change the origin. Consider a point mass moving at the origin, then angular momentum would be zero, right...

The spin projection in any direction won't be as much as the total spin as mentioned by Dr. Claude. There are quantum effects which make this a bit different than a classical object pointing somewhere. A spin pointing up along some axis when measured on some different axis will measure some...

I am not sure you know how to read the diagram correctly. The part left of the middle is actually a different direction or slice than the right half of the diagram. That is typical situation for energy band diagrams. Instead of just plotting how the energy bands go along one direction, it takes...

Couldn't you look at as the complement operator actually taking two arguments, the set to complement and the set that is the "universe"? The empty set would be unique that way. It just doesn't make sense to complement anything without defining (perhaps implicitly) what is the entire set. So you...

Hello, perhaps there is some confusion about these terms. Adiabatic means no heat is transferred to or from the subsystem and its surroundings. It does not say anything about the entropy change. The word for no entropy change is isentropic or reversible. A slowly carried out adiabatic expansion...

Welcome to PF. The canonical commutator ##[x, p] = i\hbar## can be derived with basic calculus (the product rule). We apply the operators x and p to a wave function f(x) in different orders and compare $$px\,f(x) = -i\hbar \frac{\partial}{\partial x} x f(x) = -i\hbar (1+...

Sure, for example there is a treatment with classical field theory and Lagrangian mechanics that describes light in terms of the principle of least action The Classical Lagrangian density is split up into two parts, one that corresponds to the interaction with currents and charges, and one that...

The fields outside are not zero for a finite capacitor, and the work is path independent. We say that there is a fringing effect at the boundary. Numerical techniques are used for realistic geometries for electrostatics and magnetostatics. For example this person has used the finite difference...

I am curious about production amounts and prices for an annual period, for a few thousand commodity or common chemicals. I noticed a couple chemical intelligence services but they seem out of the price range for an amateur researcher. What kinds of sources are available to look further?

One approach is to note that the number of real parameters is the same as the dimensions of the Lie algebra. We consider a group element ##R## and linear-ize to first order to produce an element ##R' =R+\epsilon K ## which must obey the group properties up to first order. $$\begin{align*}...