Dressed elliptic string solutions on $$\mathbb {R}\times \hbox {S}^2$$

The European Physical Journal C - We discuss the possible existence of the fully-heavy tetraquarks. We calculate the ground-state energy of the $$bb {\bar{b}} {\bar{b}}$$ bound state, where b...     

A photoelastic fiber-optic strain gage

This paper reports on the development of a photoelastic fiber-optic strain gage sensitive to transverse strain. The sensing element is made from an epoxy resin which is stress frozen to passively achieve the quadrature condition. Light, emitted from an LED operating at 820 nm, is transmitted to and from the sensing element via multi-mode fibers and the signal is detected using a dual-channel operational photodiode/amplifier.This unique combination of optics and electronics produces a fiber-optic sensor having a high signal to noise ratio and a measurement system which is lead-in/out insensitive. Results show that strains on the order of 1 microstrain can be measured over an 800 microstrain range when a dummy gage is used for compensation.Paper was presented at the 1992 SEM Spring Conference on Experimental Mechanics held in Las Vegas, NV on June 8–11.