arXiv subjects

Luca Bonanomi

Publications and source records attributed to Luca Bonanomi.

4 recordsLinked to original sources

arXiv2019

Plant cells-based biological matrix composites

The global increase in materials consumption calls for innovative materials, with tailored performance and multi-functionality, that are environmentally sustainable. Composites from renewable resources offer solutions to fulfil these demands but have so far been dominated by hybrid petrochemicals-based matrixes reinforced by natural fillers. Here, we present biological matrix composites with properties comparable to wood and commercial polymers. The biocomposites are obtained from cultured, undifferentiated plant cells, dehydrated and compressed under controlled conditions, forming a lamellar microstructure. Their stiffness and strength surpass that of commercial plastics of similar density, like polystyrene, and low-density polyethylene, while being entirely biodegradable. The properties can be further tuned varying the fabrication process. For example, filler particles can be integrated during fabrication, to vary the mechanical response or introduce new functionalities.

physics.app-ph↗

arXiv2017

Biomimetic temperature sensing layer for artificial skins

Artificial membranes that are sensitive to temperature are needed in robotics to augment interactions with humans and the environment and in bioengineering to improve prosthetic limbs. Existing flexible sensors achieved sensitivities of <100 mK and large responsivity albeit within narrow (<5 K) temperature ranges. Other flexible devices, working in wider temperature ranges, exhibit orders of magnitude poorer responses. However, much more versatile and temperature sensitive membranes are present in animals such as pit vipers, whose pit membranes have the highest sensitivity and responsivity in nature and are used to locate warm-blooded preys at distance. Here, we show that pectin films mimic the sensing mechanism of pit membranes and parallel their record performances. These films map temperature on surfaces with a sensitivity of at least 10 mK in a wide temperature range (45 K), have very high responsivity, and detect warm bodies at distance. The produced material can be integrated as a layer in artificial skins platforms and boost their temperature sensitivity to reach the best biological performance.

cond-mat.mtrl-sci↗

arXiv2014

Locally Resonant Granular Chain

We report the design and testing of a tunable and nonlinear mechanical metamaterial, called locally resonant granular chain. It consists of a one-dimensional array of hollow spherical particles in contact, containing local resonators. The resonant particles are made of an aluminium outer spherical shell and a steel inner mass connected by a polymeric plastic structure acting as a spring. We characterize the linear spectra of the individual particles and of one-dimensional arrays of particles using theory, numerical analysis, and experiments. A wide band gap is observed as well as tunability of the dispersive spectrum by changing the applied static load. Finally, we experimentally explore the nonlinear dynamics of the resonant particles. By using nonlinear acoustical techniques, we reveal a complex, nonclassical nonlinear dynamics.

cond-mat.mtrl-sci↗

arXiv2013

Experimental Realization of a Nonlinear Acoustic Lens with a Tunable Focus

We realize a nonlinear acoustic lens composed of a two-dimensional array of sphere chains interfaced with water. The chains are able to support solitary waves which, when interfaced with a linear medium, transmit compact pulses with minimal oscillations. When focused, the lens is able to produce compact pressure pulses of high amplitude, the "sound bullets". We demonstrate that the focal point can be controlled via pre-compression of the individual chains, as this changes the wave speed within them. The experimental results agree well both spatially and temporally with analytical predictions over a range of focus locations.

nlin.PS↗