using piezoelectric patches the stress concentration around a hole on a plate under tension is reduced and controlled. to attain the reduction in stress two placements for piezoelectric patches is investigated. the first location is top/bottom of the hole with compression induced strain and the second is left/right of the hole with tension induced strains to control the stress flow. the result ...

because of production process and constrains conditions, circular graphene sheet may be opposed to structural defect and pin hole, respectively. some of the defects and pin hole on a circular graphene sheet can be considered as an eccentric hole on the sheet. hence, analyzing behavior of circular graphene sheet with an eccentric hole is important. free vibration of an eccentric annular graphene...

Human aqueous humour was found to contain a substance which contracted the rat stomach strip. The mean activity was significantly higher in specimens from open angle glaucoma cases than in specimens from patients with cataract. The pharmacological and chromatographic properties of the active material were studied in aqueous humour obtained from cadavers; activity seemed to be due to prostagland...

We study the gravitational collapse of a self-gravitating charged scalar-field. Starting with a regular spacetime, we follow the evolution through the formation of an apparent horizon, a Cauchy horizon and a final central singularity. We find a null, weak, mass-inflation singularity along the Cauchy horizon, which is a precursor of a strong, spacelike singularity along the r = 0 hypersurface. T...

In some respects the black hole plays the same role in gravitation that the atom played in the nascent quantum mechanics. This analogy suggests that black hole mass M might have a discrete spectrum. I review the physical arguments for the expectation that black hole horizon area eigenvalues are uniformly spaced, or equivalently, that the spacing between stationary black hole mass levels behaves...

OBJECTIVE To determine the effect of pilot hole tapping, together with other variables such as pilot hole diameter, in relation to inner screw diameter and preparation method, on the insertion torque and pullout resistance of the screws used for anterior fixation of the cervical spine. METHOD Twenty polyurethane test bodies and 30 thoracic vertebrae (T1-T5) were tested. Four holes were drille...

Let G be a finite undirected graph. A vertex dominates itself and all its neighbors in G. A vertex set D is an efficient dominating set (e.d. for short) of G if every vertex of G is dominated by exactly one vertex of D. The Efficient Domination (ED) problem, which asks for the existence of an e.d. in G, is known to be NP-complete even for very restricted graph classes such as P7-free chordal gr...