arXiv subjects

Gianfranco Carotenuto

Publications and source records attributed to Gianfranco Carotenuto.

4 recordsLinked to original sources

arXiv2023

Particle-settling in iper-viscous liquids and its use for time measurement

Materials for time measurement represent a new class of functional materials, that can be used to fabricate a variety of devices useful for industrial applications, like for example the shelf-life indicators, solid-state chronometers, compact detonators, etc. Materials for time measurement require to have a continuously self-changing property that vary linearly during the time. The particle-settling phenomenon can be advantageously used to fabricate this type of materials. A theoretical model based on simple fluid-dynamics considerations for Newtonian fluids has been developed to obtain the temporal evolution of the electrical conductance for these materials, in order to verify its linear behaviour.

cond-mat.mtrl-sci↗

arXiv2019

A wearable breath sensor based on natural clinoptilolite

Low-power a.c. generators of square-wave or sinusoidal signals can be used in combination with impedimetric sensors to detect stimuli on the basis of the voltage drop taking place at the sensor electrodes. When a.c. generators with a power of only a few micro-Watts are used, this approach becomes extremely sensitive. A very low-power generator is the LCD back panel driving signal, which has a flipping polarity with a voltage of 3-5Vpp, depending on the generator model. This type of square-wave generator is contained in many low-cost handheld digital multimeters, and it is used as signal tracer to test, for example, low-frequency amplifiers. As an example, this method has been used to acquire a human breath rate pattern, by using a zeolite-based water sensor. If the generator I-V characteristics has been measured, the achieved breath pattern can be converted from a voltage drop vs. time graph to an impedance or current intensity vs. time graph.

physics.app-ph↗

arXiv2019

Kinetic investigation of water-cation interaction in clinoptilolite at room temperature

The kinetics of water adsorption by a natural zeolite (clinoptilolite) sample has been investigated by high-frequency AC current intensity measurements. According to the achieved kinetic results, cations should play a relevant role in the clinoptilolite hydration, in fact most of adsorbed water stay in the cationic sites. The water molecules associate with cation one-by-one. In particular, the forced adsorption of water molecules in a wet atmosphere is a quite slow process, while water desorption in air or dry atmosphere is a spontaneous and fast process. The observed increase of cation mobility could be adequately explained by assuming an arrangement of water molecules between the cation and the negatively charged oxygens contained in the cationic site. Such molecular arrangement could increase the strength of both dipole-cation and hydrogen bond interactions.

cond-mat.mtrl-sci↗

arXiv2014

Holographic patterning of graphene-oxide films by light-driven reduction

We report on the patterning and reduction of graphene-oxide films by holographic lithography. Light reduction can be used to engineer low-cost graphene-based devices by performing a local conversion of insulating oxide into the conductive graphene. In this work, computer generated holograms have been exploited to realize complex graphene patterns in a single shot, differently from serial laser writing or mask-based photolithographic processes. The technique has been further improved by achieving speckle noise reduction: submicron and diffraction-limited features have been obtained. In addition we have also demonstrated that the gray-scale lithography capability can be used to obtain different reduction levels in a single exposure.

cond-mat.mtrl-sci↗