Abstract. Reflector antennas are characterized by very high gains (30 dB and higher) and narrow main beams. They are widely used in satellite and line-of-sight microwave communications as well as in radar. Reflector antennas operate on principles known long ago from the theory of geometrical optics. The first reflector system was made by Hertz back in 1888 (a cylindrical reflector fed by a dipo...

We study momentum and energy propagation in 1D tapered chains of spherical granules which interact according to a Hertz potential. In this work we apply the binary collision approximation, which is based on the assumption that transfer of energy along the chain occurs via a succession of two-particle collisions. Although the binary theory correctly captures the trends of increase or decrease of...

The author demonstrates a stable Lagrangian solid modeling method, tracking the interactions of solid mass particles, rather than using a meshed grid. This numerical method avoids the problem of tensile instability often seen with Smooth Particle Applied Mechanics by having the solid particles apply stresses expected with Hooke’s law, as opposed to using a smoothing function for neighboring sol...

Aim at the random problems of flying gangue movement in steeply dipping seam mining, based on the spherical flying gangue movement model, computational formula of collision restitution coefficient was established when flying gangue shocks bottom plate of working face according to the theory of Hertz classical elastic collision; Considering the influences of the randomness such as the density, r...

Weak microwave radiation (WMR) in our environment has raised health concerns in the public. Among those, communication frequencies are more than ever becoming widespread and their effects need thorough studies. A correct understanding of these effects in-vivo by in-vitro experiments shall preferentially use primary cells. In this study we compared non-modulated (CW) and modulated WMR exposure o...

Strongly nonlinear phononic crystals were assembled from a chain of Parylene-C coated steel spheres in a polytetrafluoroethylene holder. This system exhibits strongly nonlinear properties and extends the range of materials supporting sonic-vacuum-type behavior. The combination of a high density core and a soft (low elastic modulus) coating ensures a relatively low velocity of wave propagation. ...

Recent experimental research indicates that superelastic shape memory alloy nickel–titanium (NiTi) is superior to stainless steel against wear and could be applied in tribological engineering. It is believed that the super wear resistance of shape memory alloys is mainly due to the recovery of the superelastic deformation. Our recent wear study indicates that wear rate is very sensitive to the ...

Concurrent generation and mixing phenomenon of thermoacoustic (TA) and magnetoacoustic (MA) waves in water are predicted and observed. A theory unifying TA and MA is further put forward to analyze it. By scaling down the radio frequency in thermoacoustics to the low mega Hertz range and by incorporating appropriately a static magnetic field, TA and MA waves are simultaneously generated in the c...

Phase-shifting interferometry based on the integrating-bucket technique with sinusoidal phase modulation is studied theoretically and demonstrated experimentally to obtain phase maps from double-beam interferometers. The method uses four frames obtained by integration of the time-varying intensity in an interference pattern during the four quarters of the modulation period. An optimum sinusoida...

ABSTRACT: In the paper a transformational impact force reconstruction method is presented, which features a one-point strain measurement in a mechanical transducer. To determine the spectral transmittance of a section of the mechanical transducer necessary in the reconstruction process, strain waves propagating in the transducer are used: the incident, and the first reflected one, created by th...