Results 31 to 40 of about 84,329 (313)

VHF coherent radar signals from the E region ionosphere and the relationship to electron drift velocity and ion acoustic velocity [PDF]

, 2002
The Scandinavian Twin Auroral Radar Experiment (STARE) coherent radar system measures the Doppler shifts caused by ∼1 m plasma waves in the high-latitude E region ionosphere.
Nielsen, E., del Pozo, C., del Pozo, C. F., Del-Pozo, Carlos, Williams, P., Williams, P. J. S.   +5 more
core   +1 more source

Accounting for convective effects in zero-Mach-number thermoacoustic models [PDF]

, 2014
This paper presents a methodology to account for some mean-flow effects on thermo-acoustic instabilities when using the zero-Mach-number assumption. It is shown that when a computational domain is represented under the M=0 assumption, a nonzero-Mach ...
Nicoud, F., Motheau, Emmanuel, Nicoud, Franck, Selle, Laurent, Motheau, E., Selle, L.   +5 more
core   +1 more source

A Comparative Study of In Situ Methodologies for Assessment of RF EMF Exposure From a 5G FR2 Base Station

IEEE Access
In this work, in situ measurements of the radio frequency electromagnetic field exposure have been conducted for an indoor massive MIMO 5G base station operating at 26–28 GHz.
Samuel Goegebeur, Kenneth Deprez, Davide Colombi, Jens Eilers Bischoff, Carla Di Paola, Bram Stroobandt, Leen Verloock, Sam Aerts, Christer Tornevik, Wout Joseph   +9 more
doaj   +1 more source

Reflection of an acoustic line source by an impedance surface with uniform flow

, 2014
An exact analytic solution is derived for the 2D acoustic pressure field generated by a time-harmonic line mass source located above an impedance surface with uniform grazing flow. Closed-form asymptotic solutions in the far-field are also provided.
Gabard, Gwénaël, Brambley, E.J., Gabard, G., Brambley, E. J.   +3 more
core   +1 more source

Directional acoustic transmission based on metamaterials

AIP Advances, 2018
To explore the simple low-loss operation of directional acoustic transmission technology, the propagation of acoustic waves in resonant phononic crystals was studied, and a transmission model based on acoustic metamaterials was constructed.
Shuai Tang, Jianning Han, Tingdun Wen
doaj   +1 more source

Layer guided shear horizontally polarized acoustic plate modes

, 2002
The theoretical basis describing Love waves propagating on a finite thickness substrate covered by a finite thickness solid layer having a lower shear acoustic speed is considered.
Newton, Michael, G. McHale, F. Martin, Martin, Fabrice, Newton, MI, M. I. Newton, McHale, G, Martin, F, McHale, Glen   +8 more
core   +1 more source

Air‐Pressure–Actuated Vibroacoustic Metamaterial With Tunable Bandgap: Design, Modeling, and Characterization

Advanced Engineering Materials, EarlyView.
This article presents the design, modeling, and characterization of air‐pressure–actuated programmable vibroacoustic metamaterials (PVAMM). The study focuses on leveraging air pressure to dynamically tune resonance frequencies for effective noise attenuation.
William Kaal, Michael M. Becker, Sarah C. L. Fischer   +2 more
wiley   +1 more source

Holographic measurement of surface acoustic wave parameters in crystals [PDF]

Modern Electronic Materials, 2019
The theoretical basis of a specialized technique for applying digital holographic interferometry to measure the parameters of surface acoustic waves is presented, a measuring system for visualization and quantitative analysis of the parameters of ...
Michael E. Gusev, Yuri N. Zakharov
doaj   +3 more sources

Ion acoustic traveling waves [PDF]

Journal of Plasma Physics, 2014
AbstractModels for traveling waves in multi-fluid plasmas give essential insight into fully nonlinear wave structures in plasmas, not readily available from either numerical simulations or from weakly nonlinear wave theories. We illustrate these ideas using one of the simplest models of an electron–proton multi-fluid plasma for the case where there is ...
Webb, G. M., Burrows, R. H., Ao, X., Zank, G. P.   +3 more
openaire   +2 more sources

Karl Popper and the Mechanisms of Hydrogen Embrittlement

Advanced Engineering Materials, EarlyView.
Representation of the beginning of loss of ductility rather than embrittlement. Small concentrations of hydrogen in a diffusible form within iron are well‐established to harm the mechanical integrity of steels. There are theories that attempt to explain the pernicious role of hydrogen.
H. K. D. H. Bhadeshia
wiley   +1 more source