Abstract Through its atmospheric teleconnections, El Niño–Southern Oscillation (ENSO) shifts and disrupts weather climate patterns far beyond the equatorial Pacific where it occurs often resulting in catastrophic consequences many countries of world. It is also largest source seasonal interannual predictability. Despite huge importance, ENSO forecasting still not performed operationally at longer leads than about 6 months ahead. At same time, there mounting scientific evidence that forecasts...

An example of a three dimensional flat paracontact metric manifold with respect to Levi-Civita connection is constructed. It shown that no such exists for odd dimensions greater than or equal five.

This paper presents a 6×6 AlN piezoelectric micromachined ultrasonic transducers (PMUT) array with competitive performance as an actuator and sensor compared other devices using the material. The novelty is that AlN-PMUT fabricated over pre-processed CMOS wafers allowing compactness, better signal processing higher fill factor (not limited by wafer bonding) than reported. squared PMUT achieves acoustic sensitivities of 130 Pa·mm·V <sup xmlns:mml="http://www.w3.org/1998/Math/MathML"...

This study presents a squared AlN piezoelectric micromachined ultrasonic transducer (PMUT). Using this PMUT greater level of output pressure and higher reception sensitivity has been achieved, compared with the state-of-the-art. Another outstanding characteristic for is that it can be monolithically integrated on CMOS substrate, being remarkably advantageous in relation to bonding method implemented until now.

Inclined cables are essential structural elements that used most prominently in cable-stayed bridges. When the bridge deck oscillates due to an external force, such as passing traffic, cable vibrations can arise not only plane of excitation, but also perpendicular plane. This undesirable phenomenon be modeled auto-parametric resonance between in-plane and out-of-plane modes vibration cable. In this paper, we consider a three-mode model, capturing second in-plane, first modes, use it study...

A novel AlN PMUT compatible with CMOS-MEMS process is presented. The design a squared membrane 4 different sections. operational frequency of the device in liquid 10 MHz range. Our FEM model shows that cross-slit increases displacement as well acoustic pressure outputs by factor 10. resulted sections are sealed passive Si <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sub> N xmlns:xlink="http://www.w3.org/1999/xlink">4</sub> layer allowing...

Novel Si-based nanosize mechanical resonator has been top-down fabricated. The shapeof the resonating body numerically derived and consists of seven star-polygons that forma fractal structure. actual is defined by focused ion-beam implantation on a SOIwafer where its 18 vertices are clamped to nanopillars. structure suspended over 10 mtrench width 12 m. Its thickness 0.040 m fabrication process andprescribes Young's modulus 76 GPa which significantly lower than value bulk material.The...

In this paper are investigated strictly self-similar fractals that composed of an infinite number regular star-polygons, also known as Sierpinski $n$-gons, $n$-flakes or polyflakes. Construction scheme for Sierpinsky $n$-gon and $n$-flake is presented where the dimensions $\infty$-gon $\infty$-flake computed to be 1 2, respectively. These put in a general context Iterated Function Systems applied visualisation geometric iterations initial polygons, well sets points lie on attractors IFS...

Two piezoelectric micromachined ultrasonic transducers (PMUTs) with a mode shape like free membrane and resonance frequency around 7 MHz in liquid environment are proposed this paper. Here we evaluate the influence of linear holes (two or four holes) movement consequently output pressure. FEM simulations show how increase velocity at least 1.4× factor relation clamped PMUT. Also, experimental verification fluorinert (FC-70) allows to demonstrate capability use them an surface pressure range...

The cables used in cable-stayed bridges are known to have low levels of damping and, as a result, their large amplitude vibrations represent problem for the structure. Therefore, augmenting natural is strategy decrease vibration response. Here we investigate how this precaution changes dynamics cable We use four-mode model an inclined specifically, that fixed at top, and vertically excited base order simulate excitation due deck motion. This simulates internal resonances between in-plane...

Long-lead climate predictions are increasingly in demand due to change. Through its well-known atmospheric teleconnections El Ni&amp;#241;o Southern Oscillation (ENSO) is a leading source of seasonal and interannual predictability, but currently operational ENSO forecasts limited about two seasons advance. At the same time scientific literature pointing feasibility one year even more advance increasing. The early anticipation could prepare vulnerable communities around world help mitigate...

Novel top down Si-based electrostatically driven clamped-clamped resonator was manufactured. The resonating body (12 μm] in length) is a fractal with hexagonal shape based on cell-triangle side of 3.354 [pm]. experimental measurements and simulations proved that the device can resonate at many different excitation frequencies allowing multiple operational responses. size, power needed for actuation are comparable ones single beam resonator.