Pablo Damián Ravazzoli

Universidad Nacional del Centro de la Provincia de Buenos Aires | UNICEN · Departamento de Ciencias Físicas y Ambientales

In this work we study the change on the wettability and solid properties of microcrystalline cellulose (Avicel PH101)after it was wet and dried, through drop penetration experiments in slightly compacted porous beds. We perform these experiments with water and a silicone oil, (Polidimethilsyloxane–PDMS) and we determine a dimensionless parameter th...

In this study, we present an experimental investigation of the flow structure changes in non-Newtonian fluids subjected to periodic variable fluxes inside rigid-walled tubes. We employ a liquid mixture composed of water and polyacrylamide to account for various rheological properties. We obtain the velocity fields for each experimental case using t...

We study the equilibrium solutions of a fluid bridge that connects a horizontal solid substrate with a fluid phase (typically, air) while surrounded by another immiscible liquid. The shape of each interface is considered as a single curve with axial symmetry and constant curvature. The interface between the bridge and the air phase is a spherical c...

We study the equilibrium solutions of a sessile drop on top of a horizontal substrate when it is partially covered by another inmiscible liquid, so that part of the drop is in contact with a third fluid (typically, air). The shapes of the interfaces are obtained by numerical integration of the differential equations resulting from the application o...

We study the retraction of liquid filaments resting on inclined solid substrates under partially wetting condition. This one causes each extreme of the filament to retract and form a region of mass accumulation (head) that subsequently develops a neck at its rear part. This neck then breaks up into a separate drop, while the rest of the filament re...

We study the equilibrium shape of a liquid drop resting on top of a liquid surface, i.e., a floating lens. We consider the surface tension forces in nonwetting situations (negative spreading factor), as well as the effects of gravity. We obtain analytical expressions for the drop shape when gravity can be neglected. Perhaps surprisingly, when inclu...

We study the equilibrium shape of a liquid drop resting on top of a liquid surface, i.e., a floating lens. We consider the surface tension forces in non--wetting situations (negative spreading factor), as well as the effects of gravity. We obtain analytical expressions for the drop shape when gravity can be neglected. Perhaps surprisingly, when inc...

We study the contact-angle hysteresis and morphology changes of a liquid drop sitting on a solid substrate inclined with respect to the horizontal at an angle α. This one is always smaller than the critical angle, α crit , above which the drop would start to slide down. The hysteresis cycle is performed for positive and negative α's (|α| < α crit),...

We report experiments, modeling, and numerical simulations of the self-assembly of particle patterns obtained from a nanometric metallic square grid. Initially, nickel filaments of rectangular cross section are patterned on a SiO 2 flat surface, and then they are melted by laser irradiation with ∼18-ns pulses. During this time, the liquefied metal...

We study the contact angle hysteresis and morphology changes of a liquid drop sitting on a solid substrate inclined with respect to the horizontal at an angle $\alpha$. This one is always smaller than the critical one, $\alpha_{crit}$, above which the drop would start to slide down. The hysteresis cycle is performed for positive and negative $\alph...

We report experiments, modeling and numerical simulations of the self--assembly of particle patterns obtained from a nanometric metallic square grid. Initially, nickel filaments of rectangular cross section are patterned on a SiO$_2$ flat surface, and then they are melted by laser irradiation with $\sim 20$ ns pulses. During this time, the liquefie...

A rectangular grid formed by liquid filaments on a partially wetting substrate evolves in a series of breakups leading to arrays of drops with different shapes distributed in a rather regular bidimensional pattern. Our study is focused on the configuration produced when two long parallel filaments of silicone oil, which are placed upon a glass subs...

A rectangular grid formed by liquid filaments on a partially wetting substrate evolves in a series of breakups leading to arrays of drops with different shapes distributed in a rather regular bidimensional pattern. Our study is focused on the configuration produced when two long parallel filaments of silicone oil, which are placed upon a glass subs...

We study the hydrodynamic mechanisms involved in the motion of the contact line formed at the end region of a liquid filament laying on a planar and horizontal substrate. Since the flow develops under partially wetting conditions, the tip of the filament recedes and forms a bulged region (head), that subsequently develops a neck region behind it. L...

We study the hydrodynamic mechanisms involved in the motion of the contact line formed at the end region of a liquid filament laying on a planar and horizontal substrate. Since the flow develops under partially wetting conditions, the tip of the filament recedes and forms a bulged region (head), that subsequently develops a neck region behind it. L...

In this paper we study the morphology of drops formed on partially wetting substrates, whose footprint is not circular. This type of drops is a consequence of the breakup processes occurring in thin films when anisotropic contact line motions take place. The anisotropy is basically due to hysteresis effects of the contact angle since some parts of...

Existen diversos programas para el mejoramiento de la enseñanza de las Ciencias Exactas y Naturales, que buscan además generar vocaciones por las disciplinas científicas en general y la Física en particular. Además, la implementación del programa Conectar Igualdad, que alcanzó 5 millones de netbooks entregadas a estudiantes de la escuela secundaria...

Póster presentado en la 92º Reunión de la AFA

Póster presentado en la 91 Reunión Anual de la AFA