Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userFlux through a Mobius strip?
151
0
0.0
(
0
)
Added by
Leonardo Fernandez-Jambrina
Publication date
2021
fields
Physics
and research's language is
English
Authors
L. Fernandez-Jambrina
Ask ChatGPT about the research
No Arabic abstract
Integral theorems such as Stokes and Gauss are fundamental in many parts of Physics. For instance, Faradays law allows computing the induced electric current on a closed circuit in terms of the variation of the flux of a magnetic field across the surface spanned by the circuit. The key point for applying Stokes theorem is that this surface must be orientable. Many students wonder what happens to the flux through a surface when this is not orientable, as it happens with a Mobius strip. On an orientable surface one can compute the flux of a solenoidal field using Stokes theorem in terms of the circulation of the vector potential of the field along the oriented boundary of the surface. But this cannot be done if the surface is not orientable, though in principle this quantity could be measured on a laboratory. For instance, checking the induced electric current on a circuit along the boundary of a surface if the field is a variable magnetic field. We shall see that the answer to this puzzle is simple and the problem lies in the question rather than in the answer.
rate research
Read More
We report on experiments with Mobius strip microlasers which were fabricated with high optical quality by direct laser writing. A Mobius strip looks like a ring with a twist and exhibits the fascinating property that it has only one boundary and a one-sided nonorientable surface. Hence, in contrast to conventional ring or disk resonators, a Mobius strip cavity cannot sustain Whispering Gallery Modes (WGMs). Comparison between experiments and FDTD simulations evidenced that the resonances are indeed not of whispering gallery type, but localized along periodic geodesics. This finding is supported, on the one hand, by an extension of the effective index approximation to curved layers, and on the other hand, by an algorithm to systematically identify the periodic geodesics.
Here we report the synthesis, structure and detailed characterisation of three n-membered oxovanadium rings, Na$_n$[(V=O)$_n$Na$_n$(H$_2$O)$_n$($alpha$, $beta$, or $gamma$-CD)$_2$]$m$H$_2$O (n = 6, 7, or 8), prepared by the reactions of (V=O)SO$_4$$cdot$$x$H$_2$O with $alpha$, $beta$, or $gamma$-cyclodextrins (CDs) and NaOH in water. Their alternating heterometallic vanadium/sodium cyclic core structures were sandwiched between two CD moieties such that O-Na-O groups separated neighbouring vanadyl ions. Antiferromagnetic interactions between the $S$ = 1/2 vanadyl ions led to $S$ = 0 ground states for the even-membered rings, but to two quasi-degenerate $S$ = 1/2 states for the spin-frustrated heptanuclear cluster.
A closed linkage mechanism in three-dimensional space is an object comprising rigid bodies connected with hinges in a circular form like a rosary. Such linkages include Bricard6R and Bennett4R. To design such a closed linkage, it is necessary to solve a high-degree algebraic equation, which is generally difficult. In this lecture, the author proposes a new family of closed linkage mechanisms with an arbitrary number of hinges as an extension of a certain Bricard6R. They have singular properties, such as one-dimensional degree of freedom (1-DOF), and certain energies taking a constant value regardless of the state. These linkage mechanisms can be regarded as discrete Mobius strips and may be of interest in the context of pure mathematics as well. However, many of the properties described here have been confirmed only numerically, with no rigorous mathematical proof, and should be interpreted with caution.
Physics Education Research frequently investigates what students studying physics do on small time scales (e.g. single courses, observations within single courses), or post-education time scales (e.g., what jobs do physics majors get?) but there is little research into how students get from the beginning to the end of a physics degree. Our work attempts to visualize students paths through the physics major, and quantitatively describe the students who take physics courses, receive physics degrees, and change degree paths into and out of the physics program at Michigan State University.
The flux penetration near a semicircular indentation at the edge of a thin superconducting strip placed in a transverse magnetic field is investigated. The flux front distortion due to the indentation is calculated numerically by solving the Maxwell equations with a highly nonlinear $E(j)$ law. We find that the excess penetration, $Delta$, can be significantly ($sim$ 50%) larger than the indentation radius $r_0$, in contrast to a bulk supercondutor in the critical state where $Delta=r_0$. It is also shown that the flux creep tends to smoothen the flux front, i.e. reduce $Delta$. The results are in very good agreement with magneto-optical studies of flux penetration into an YBa$_2$Cu$_3$O$_x$ film having an edge defect.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
