A sound reproduction system usually consists of several types of loudspeakers to cater to sophisticated applications. The directivity of a loudspeaker is a measure of its efficiency in sending sounds to a particular direction instead of all directions. Demand to control the directivity of a sound reproduction system is gaining momentumwith many new designs of directional loudspeakers, including...

The subject of enhancing microstrip patch antennas directivity, using either a frequency selective surface (FSS) or a double-negative (DNG) metamaterial slab, has been investigated by a number of researchers in recent years. The purpose of this paper is to show that we can also achieve the same goal by using a much simpler design for the superstrate, namely a dielectric slab, whose performance ...

The design of time-invariant beamformers is often posed as an optimization problem using practical design constraints. In many scenarios it is sufficient to assume that the microphones have an omnidirectional directivity pattern, a flat frequency response in the range of interest, and a 2D environment in which wavefronts propagate as a function of azimuth angle only. In this paper we consider a...

The directivity index is a parameter that is commonly used to characterize the performance of directional hearing aids, and is determined from the measured directional response. Since this response is different for a hearing aid worn on a person as compared to when it is in a free field, directivity index measurements of hearing aids are usually done under simulated real-ear conditions. Details...

Horn antennas can result in good impedance matching between the waveguide and free space due to the gradual increase in the aperture size. In this paper, a novel plasmonic sectoral horn nanoantenna based on using lens in the aperture is proposed. It is investigated that in addition to improvement of the directivity, the reflection coefficient is also reduced using the proper lens structure. The...

The northward migration of the Mendocino Triple Junction is associated with complex faulting within the Gorda plate and in the convergent zone between the Gorda and North American plates. This region has experienced substantial recent large earthquake activity, and quantification of these faulting processes i essential for understanding the evolution of the triple junction. Using an empirical G...

near-fault ground motions have caused very much damage in the vicinity of seismic sources during recent earthquakes. it is well known that under specific circumstances, intensive ground shakings near fault ruptures may be characterized by short-duration impulsive motions. this pulse-type motion is generally particular to the forward direction, where the fault rupture propagates towards the site...

Abstract On 6 February 2023, two large earthquakes with magnitude 7.8 and 7.6 rocked south-central Türkiye northwestern Syria. At the time of writing, death toll exceeded 50,000 in 7200 The epicenter first mainshock was located ?15 km east Anatolian fault (EAF), second earthquake (9 hr later) initiated ?90 to north on east–west-trending Sürgü fault. Aftershocks delineate lengths ?350 ?170 km, r...