We show here the existence of acoustic metamaterial, in which both the effective density and bulk modulus are simultaneously negative, in the true and strict sense of an effective medium. Our double-negative acoustic system is an acoustic analogue of Veselago's medium in electromagnetism, and shares many unique consequences, such as negative refractive index. The double negativity in acoustics ...

Einstein considered general covariance to characterize the novelty of his General Theory of Relativity (GTR), but Kretschmann thought it merely a formal feature that any theory could have. The claim that GTR is “already parametrized” suggests analyzing substantive general covariance as formal general covariance achieved without hiding preferred coordinates as scalar “clock fields,” much as Eins...

A six dimensional manifold of symmetric signature (3,3) is proposed as a space structure for building combined theory gravity and electromagnetism. Special metric tensor proposed, yielding the which combines properties Riemann, Weyl Finsler spaces. Geodesic line equations are constructed where coefficients can be divided into depending on (relating to gravitational interaction) vector field ele...

In this paper, we study the higher Yang-Mills theory in framework of gauge theory. It was shown that 2-form electromagnetism can be generalized to with group U(1) replaced by a crossed module Lie groups. To extend even structure, develop 3-form 2-crossed First, give an explicit construction non-degenerate symmetric G-invariant forms on algebras. Then, derive 3-Bianchi-Identities for 3-curvature...

this paper addresses the vehicle routing problem with delivery time cost. this problem aims to find a set of routes of minimal total costs including the travelling cost and delivery time cost, starting and ending at the depot, in such a way that each customer is visited by one vehicle given the capacity of the vehicle to satisfy a specific demand. in this research, a hybrid metaheuristic approa...

The dynamic nature of projects and the fact that they are carried out in changing environments, justify the need for their periodic monitoring and control. Collection of information about the performance of projects at control points costs money. The corrective actions that may need to be taken to bring the project in line with the plan also costs money. On the other hand, penalties are usually...