Flavio Noca

Bio: Flavio Noca is an academic researcher from University of Applied Sciences Western Switzerland. The author has contributed to research in topics: Drone & Vorticity. The author has an hindex of 15, co-authored 32 publications receiving 1418 citations. Previous affiliations of Flavio Noca include California Institute of Technology & Jet Propulsion Laboratory.

Molecular Dynamics Simulation of Contact Angles of Water Droplets in Carbon Nanotubes

Abstract: We study the behavior of water droplets confined in a carbon nanotube by means of parallel molecular dynamics simulations We report radial density profiles, radial hydrogen bond distributions, and contact angles for tube radii ranging from 125 to 375 A and for droplets containing up to 4632 water molecules Our results indicate nonwetting behavior of the pristine CNT at room temperatures

Pattern-aligned carbon nanotube growth and tunable resonator apparatus

Abstract: A tunable nanomechanical oscillator device and system is provided. The nanomechanical oscillator device comprising at least one nanoresonator, such as a suspended nanotube, designed such that injecting charge density into the tube (e.g. by applying a capacitively-cuopled voltage bias) changes the resonant frequency of the nanotube, and where exposing the resonator to an RF bias induces oscillitory movement in the suspended portion of the nanotube, forming a nanoscale resonator, as well as a force sensor when operated in an inverse mode. A method of producing an oriented nanoscale resonator structure with integrated electrodes is also provided.

Bioinspired morphing wings for extended flight envelope and roll control of small drones

Abstract: Small-winged drones can face highly varied aerodynamic requirements, such as high manoeuvrability for flight among obstacles and high wind resistance for constant ground speed against strong headwinds that cannot all be optimally addressed by a single aerodynamic profile. Several bird species solve this problem by changing the shape of their wings to adapt to the different aerodynamic requirements. Here, we describe a novel morphing wing design composed of artificial feathers that can rapidly modify its geometry to fulfil different aerodynamic requirements. We show that a fully deployed configuration enhances manoeuvrability while a folded configuration offers low drag at high speeds and is beneficial in strong headwinds. We also show that asymmetric folding of the wings can be used for roll control of the drone. The aerodynamic performance of the morphing wing is characterized in simulations, in wind tunnel measurements and validated in outdoor flights with a small drone.

Chemistry of Carbon Nanotubes

Abstract: Department of Materials Science, University of Patras, 26504 Rio Patras, Greece, Theoretical and Physical Chemistry Institute, National Hellenic Research Foundation, 48 Vass. Constantinou Avenue, 116 35 Athens, Greece, Institut de Biologie Moleculaire et Cellulaire, UPR9021 CNRS, Immunologie et Chimie Therapeutiques, 67084 Strasbourg, France, and Dipartimento di Scienze Farmaceutiche, Universita di Trieste, Piazzale Europa 1, 34127 Trieste, Italy

Vortex-induced vibrations

Abstract: This review summarizes fundamental results and discoveries concerning vortex-induced vibration (VIV), that have been made over the last two decades, many of which are related to the push to explore very low mass and damping, and to new computational and experimental techniques that were hitherto not available. We bring together new concepts and phenomena generic to VIV systems, and pay special attention to the vortex dynamics and energy transfer that give rise to modes of vibration, the importance of mass and damping, the concept of a critical mass, the relationship between force and vorticity, and the concept of "effective elasticity," among other points. We present new vortex wake modes, generally in the framework of a map of vortex modes compiled from forced vibration studies, some of which cause free vibration. Some discussion focuses on topics of current debate, such as the decomposition of force, the relevance of the paradigm flow of an elastically mounted cylinder to more complex systems, and the relationship between forced and free vibration.

On the Water−Carbon Interaction for Use in Molecular Dynamics Simulations of Graphite and Carbon Nanotubes

Abstract: A systematic molecular dynamics study shows that the contact angle of a water droplet on graphite changes significantly as a function of the water−carbon interaction energy. Together with the observation that a linear relationship can be established between the contact angle and the water monomer binding energy on graphite, a new route to calibrate interaction potential parameters is presented. Through a variation of the droplet size in the range from 1000 to 17 500 water molecules, we determine the line tension to be positive and on the order of 2 × 10-10 J/m. To recover a macroscopic contact angle of 86°, a water monomer binding energy of −6.33 kJ mol-1 is required, which is obtained by applying a carbon−oxygen Lennard-Jones potential with the parameters eCO = 0.392 kJ mol-1 and σCO = 3.19 A. For this new water−carbon interaction potential, we present density profiles and hydrogen bond distributions for a water droplet on graphite.

Selective ion passage through functionalized graphene nanopores.

Abstract: We design functionalized nanopores in graphene monolayers and show by molecular dynamics simulations that they provide highly selective passage of hydrated ions. Only ions that can be partly stripped of their hydration shells can pass through these ultrasmall pores with diameters of ∼5 A. For example, a fluorine−nitrogen-terminated pore allows the passage of Li+, Na+, and K+ cations with the ratio 9:14:33, but it blocks the passage of anions. The hydrogen-terminated pore allows the passage of F−, Cl−, and Br− anions with the ratio 0:17:33, but it blocks the passage of cations. These nanopores could have potential applications in molecular separation, desalination, and energy storage systems.