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...

abstract annular pancreas (ap) is a rare congenital malformation resulting from failure of pancreas ventral anlage rotation with the duodenum. this leads to a ring of pancreatic tissue that envelops the duodenum. clinical manifestations of ap most commonly develop in infancy or early childhood but can present at any age. the diagnosis of ap, usually suggested by an upper gi series or abdominal ...

The large-distance penetration capability of an annular-shaped charge under multipoint synchronous initiation was experimentally investigated. For different annular structures and settings, incident angle, collision type detonation waves, overpressure on the shaped charge’s liner at adjacent points were analyzed using wave propagation theory. Furthermore, a standoff distance 1–15 m from 20 mm t...

We introduce a multilevel spiral phase plate (SPP) limited by a pseudoring polygonal aperture (PRPA). Such an SPP has the advantages of easier fabrication and greater suppression of the sidelobes of the diffraction field over that generated with a polygonal aperture (PA). The Fraunhofer diffraction fields generated by an SPP with a PRPA or with a PA have the same topological charge features and...

Models of surface fractures due to volcanic loading of an elastic plate are commonly used to constrain the thickness of planetary lithospheres, but discrepancies exist in predictions of the style of initial failure and in the nature of subsequent fracture evolution. In this study, we perform an experiment to determine the mode of initial failure due to the incremental addition of a conical load...

Metamaterial cloaks control the propagation of waves to make an object invisible or insensible. To manipulate elastic waves in space, a metamaterial cloak is typically embedded in a base system that includes or surrounds a target object. The embedding is undesirable because it structurally weakens or permanently alters the base system. In this study, we propose a new add-on metamaterial elastic...