PVDF Ultrasonic Sensors for In-Air Applications: A Review.

Polyvinylidene fluoride (PVDF), a material with ferroelectric characteristics, is still extremely topical for the manufacturing of transducers, and different examples, some of which have been actively commercialized since the 1980s, are reported in the literature. In this work, we present a review focused on the PVDF technology for the manufacturing of in-air ultrasonic transducers, which found application in medical robotics, sonar systems, and automation industry (e.g.

Ultrasonic Transducers Shaped in Archimedean and Fibonacci Spiral: A Comparison.

We developed and investigated a particular geometry of transducers, emulating the shape of bats' cochlea, to transmit and receive ultrasounds in the air. Their design involved the use of polyvinylidene fluoride (PVDF) as a piezoelectric material, thanks to its excellent conformability and flexibility. This material offers the primary requirements for sensing devices in applications such as sonar system or energy harvesting technology The piezo film was folded according to both the Archimedean and Fibonacci spirals, and their performances were investigated in the frequency range from 20 kHz up to more than 80 kHz.

Influence of the Fabrication Accuracy of Hot-Embossed PCL Scaffolds on Cell Growths.

Polycaprolactone (PCL) is a biocompatible and biodegradable polymer widely used for the realization of 3D scaffold for tissue engineering applications. The hot embossing technique (HE) allows the obtainment of PCL scaffolds with a regular array of micro pillars on their surface. The main drawback affecting this kind of micro fabrication process is that such structural superficial details can be damaged when detaching the replica from the mold.

Spiral-Shaped Biologically-Inspired Ultrasonic Sensor.

Up to now, low-frequency ultrasonic transducers have been manufactured using different materials and technologies and have been inspired by the biological world, mainly by the biosonar of dolphins and bats. Our research moves in this context, which is dedicated to investigating the feasibility of developing a piezopolymer sensor capable of covering the wide frequency range of a bat's biosonar. We propose an ultrasonic sensor manufactured using a sheet of polyvinylidene fluoride curved according to a logarithmic spiral geometry as it is present in biological models of the cochlea.

Recent developments on foaming mechanical and electronic techniques for the management of varicose veins.

: Varicose veins are a common disease, causing significant impairment of quality of life to afflicted individuals. Conventional surgery has represented the traditional treatment for years, with significant post-operative complications. By the end of the 20 century, novel approaches had been developed to induce biochemical sclerosis into the treated vein in order to exclude it from blood circulation.