In Einstein’s theory of general relativity with a negative cosmological constant Λ, a vacuum spacetime is a solution to the equation Rab = Λgab and the lowest-energy solution is the anti-de Sitter spacetime. Moreover it was proved by Bocher-GibbonsHorowitz [BGH84] in 3+1 dimensions that the anti-de Sitter spacetime is the unique static, asymptotically anti-de Sitter vacuum. To give the precise ...

We numerically and experimentally demonstrated highly directional emission from photonic crystals (PCs). Our structures comprise branched waveguide channels with a periodic doubling scheme. An incident electromagnetic wave can be first split into multiple beams using PC waveguide structures. The beams were then emitted at the output waveguide ports of the PC with the same phase, which resulted ...

The paper presents a Galerkin approach for the solution of the nonlinear beam equations. Nonlinear beam analysis is required when analyzing helicopter blades or high-aspect-ratio wings. The present analysis improves on earlier solution techniques based on nonlinear finite element approach used in Refs. 1 and 2, and is the ideal choice for beam-like structures undergoing large motion. Furthermor...

Railway structures are one of the most important structures in transportation. So the lack of precise study of their dynamic behavior leads to irreparable damages. The significant factors contributing to the accurate analysis of the dynamic behavior of railways are the type of load and foundation used in it. In this study, an Euler-Bernoulli beam subjected to a moving load on a finite depth fou...

The ball-like structures were observed on the PF-1000 device at the shots with the deuterium or neon fi lling and deuterium puffi ng usually outside of the dense-pinched plasma column. The short description of the ball-like structures observed in shot #10080 and #10122 was presented in a paper [1]. In that paper, it was observed that the ball-like structures occurred at the imploding plasma she...

The electron-beam-induced current (EBIC) method is utilized in this work to visualize conductive channels formed graphene oxide as a result of resistive switching. Using metal–insulator–semiconductor (MIS) structures, an increase the electron beam induced by few orders magnitude compared with EBIC signal metal–insulator–metal (MIM) structures achieved. mechanism image formation related explaine...

Flexibility is a concept associated with variable needs of human beings.Today transformable structures are used to meet human changeable demands with different purposes and functions such as facades, roofs, sunshades, etc.A Flexible structure must be able to change physically and adapt to predetermined conditions.To provide flexibility and adaptability,transformable systems are required to poss...

Typical low-cost, low-weight microstrip base station antenna arrays with beam-scanning capabilities are taken into account. In downtowns of large cities like New York, Chicago, and in historical cities like Istanbul, where high buildings are separated by narrow but densely occupied streets, antenna arrays with approximately 20◦− 35◦ beam-widths are required to complete the cellular communicatio...

A new approach is developed for finite element modeling of muiti-layer laminated beams. Within the beam element, the laminate is decomposed as muttiple basic layers, such as base beam layers of metal like, soft-core layers of adhesives, and soft coating layers of polymers, and mass and stiffness matrices of these basic layers are assembled together to generate those matrices for the beam elemen...