Plane wave propagation in infinite two-dimensional periodic lattices is investigated using Floquet-Bloch principles. Frequency bandgaps and spatial filtering phenomena are examined in four representative planar lattice topologies: hexagonal honeycomb, Kagomé lattice, triangular honeycomb, and the square honeycomb. These topologies exhibit dramatic differences in their long-wavelength deformatio...

In order to detect the presence of defects in the composite structure of helicopter rotor blades, combined neutronand X-ray radiography investigations were performed at the Budapest Research Reactor. The rotor blades were about 10 m (or 6,5 m) long, and therefore the images were taken in several segments, and a special program was developed to reconstruct the entire radiographic image from the ...

Tissue engineering requires a mechanically stable, biocompatible, and biodegradable scaffold that permits cell adherence and proliferation, allows preservation of cell-specific properties, and suitable for surgical implantations. In this study, honeycomb collagen sheet was used for three-dimensional (3D) cultures of human skin fibroblasts and characterized as an effective and suitable scaffold ...

Graphitic carbon nitride (g-C3N4) is a visible light photocatalyst, limited by low activity mainly caused by rapid recombination of charge carriers. In the present work, honeycomb-like g-C3N4 was synthesized via thermal condensation of urea with addition of water at 450 °C for 1 h. Prolonging the condensation time caused the morphology of g-C3N4 to change from a porous honeycomb structure to a ...

We show by a combination of computer simulation and experimental characterization guided self-assembly of coherent nano-precipitates into a mesocrystal having a honeycomb structure in bulk materials. The structure consists of different orientation variants of a product phase precipitated out of the parent phase by heterogeneous nucleation on a hexagonal dislocation network. The predicted honeyc...

The effect of the core cell shape on shock absorption characteristics of biomimetically inspired honeycomb structures has been numerically investigated. The finite element models of honeycomb test specimen composed of five core cells of identical mass have been constructed, and numerical simulations have been run on PAMCRASH. The dimensions of the sides of core cells as well as the angle betwee...

Photo catalytic TiO2 coatings with well defined honeycomb structure were successfully self-assembled on glass substrates by a simple “dip and burn sol-gel method”. The crux of this new method is that the starting material for the sol-gel coating (the water solution of ammonium titanium citrate) was “doped” with “tea-leaf extracts”. Tea-leaf extracts were completely dissolved in the water soluti...

We predict planar Sb/Bi honeycomb to harbor a two-dimensional (2D) topological crystalline insulator (TCI) phase based on first-principles computations. Although buckled Sb and Bi honeycombs support 2D topological insulator (TI) phases, their structure becomes planar under tensile strain. The planar Sb/Bi honeycomb structure restores the mirror symmetry, and is shown to exhibit non-zero mirror ...

Negative stiffness honeycomb materials are comprised of unit cells that exhibit negative stiffness or snap-through-like behavior. Under an external load of small magnitude, a negative stiffness honeycomb exhibits large effective elastic modulus, equivalent to those of other standard honeycomb topologies. When the external load reaches a predetermined threshold, the negative stiffness cells begi...