Abhishek Kaushal
@hul.ariel.ac.il
Postdoctoral Fellow in Chemical Engineering
Ariel University
RESEARCH, TEACHING, or OTHER INTERESTS
Mechanical Engineering, Surfaces, Coatings and Films, Fluid Flow and Transfer Processes, Colloid and Surface Chemistry
Scopus Publications
Scholar Citations
Scholar h-index
Scholar i10-index
Scopus Publications
Abhishek Kaushal, Oleg Gendelman, Shraga Shoval, Kazuma Kuroiwa, Yuya Oaki, Syuji Fujii, and Edward Bormashenko
American Chemical Society (ACS)
We investigated the motion of spherical polystyrene/polypyrrole-coated polystyrene Janus particles placed at an air/saline interface and driven by a permanent magnetic field of ca. 0.5 T. For the sake of comparison, the motion of pure floating polystyrene particles was studied. Both kinds of the studied particles moved toward the magnet and stopped at the boundary of the near-surface well produced by the magnetic field. The Moses effect-driven motion of floating Janus particles was analyzed and investigated under different strengths of the magnetic field and salt concentrations. The study of the Janus particle displacement led to the development of a unified theoretical framework explaining the mechanism of the motion. This framework predicts that the motion of particles placed at an air-salt solution interface is not only dictated by magnetic energy but also intricately influenced by the interplay of factors, including the curvature of the interface caused by the static magnetic field, gravitational potential, and capillary forces. The orientation of the particles was observed. A qualitative explanation of the observed phenomena is suggested. The investigated process has potential for the self-assembly of particles placed at the liquid/air interface.
Abhishek Kaushal, Shraga Shoval, Bernard P. Binks, and Edward Bormashenko
American Chemical Society (ACS)
The impact of liquid marbles coated with a diversity of hydrophobic powders with various solid substrates, including hydrophobic, hydrophilic, and superhydrophobic ones, was investigated. The contact time of the bouncing marbles was studied. Universal scaling behavior of the contact time tc as a function of the Weber number (We) was established; the scaling law tc = tc(We) was independent of the kind of powder and the type of solid substrate. The total contact time consists of spreading time and retraction time. It is weakly dependent on We and this is true for all kinds of studied powders and substrates. This observation hints to the surface tension/inertia spring model governing the impact. By contrast, the spreading time ts scales as [Formula: see text], n = 0.28 - 0.30 ± 0.002. We relate the origin of this scaling law to the viscous dissipation occurring within the spreading marbles. The retraction time tr grows weakly with the Weber number. The scaling law was changed at threshold values of We ≅ 15-20. It is reasonable to explain this change with the breaking of the Leidenfrost regime of spreading under high values of We.
Abhishek Kaushal, Vishwajeet Mehandia, and Purbarun Dhar
Elsevier BV
Abhishek Kaushal, Vivek Jaiswal, Vishwajeet Mehandia, and Purbarun Dhar
Elsevier BV
Abhishek Kaushal, Vishwajeet Mehandia, and Purbarun Dhar
AIP Publishing
In this article, we report the morphing of the evaporation kinetics of paramagnetic saline sessile droplets in the presence of a magnetic field stimulus. We explore the evaporation kinetics both experimentally and theoretically and study the kinetics on hydrophilic and superhydrophobic substrates for various magnetic field strengths. We show that the evaporation rates of the paramagnetic droplets are augmented significantly and are observed to be a direct function of the magnetic field strength. Additionally, we note the modulation of the contact line transients due to the presence of the field. The influential role of solvated ions in modulating the flow behavior, and subsequently the evaporation, of droplets is present in the literature. Taking cue, we show using particle image velocimetry and infrared thermography that the magnetic field augments the thermo-solutal advection within the droplets. A mathematical analysis, based on the different internal advection mechanisms, has been proposed. We reveal that the magneto-thermal and magneto-solutal modes of internal ferrohydrodynamics are the dominant mechanisms behind the augmented evaporation dynamics. The experimentally obtained internal velocities are in excellent compliance with the model predictions. Furthermore, the enhanced evaporation rates are predicted accurately using a proposed model to scale the interfacial shear modified Stefan flow. The inferences drawn from these findings may hold several important implications in magnetic field-modulated microfluidic thermal and species transport systems.
Abhishek Kaushal, Vivek Jaiswal, Vishwajeet Mehandia, and Purbarun Dhar
Elsevier BV