arXiv subjects

L. Malik

Publications and source records attributed to L. Malik.

3 recordsLinked to original sources

arXiv2026

Ultrasound-controlled stream splitting in a microfluidic coflow

Precise control of multiphase microfluidic flows underpins applications ranging from chemical processing to biomedical diagnostics. We investigate the response of a liquid--liquid coflow in a rectangular microchannel to an externally applied standing acoustic field. Acoustic excitation destabilizes an otherwise stable interface, giving rise to a sequence of reversible interfacial regimes: waviness, splitting, relocation, and stream-droplet breakup. Remarkably, a distinct splitting regime emerges, where a continuous stream partially splits into droplets at tunable locations while retaining a thin residual stream. Unlike conventional droplet breakup, this regime avoids complete disruption of the main flow, enables droplet generation at high capillary numbers, and allows spatial control over droplet formation. Extending across a broad range of capillary numbers, we examine how variations in flow conditions and applied acoustic power influence these regimes. Combining experiments, numerical simulations, and theoretical scaling, we elucidate the mechanisms governing this droplet generation mode and the associated regime transitions. Systematic measurements show that droplet size and residual stream thickness are governed primarily by hydrodynamic parameters, whereas the acoustic field controls the onset and spatial location of the breakup. These results establish a simple avenue for stream splitting and drop generation on-demand in a microfluidic coflow, opening new possibilities for spatially programmable manipulation of multiphase flows.

physics.flu-dyn↗

arXiv2025

Living droplets with mesoscale swimmers

We study the activity of 'living' droplets, which confine tens of swimming meso-organisms in 3D using a superhydrophobic substrate. With few swimmers, the droplet oscillates at its inherent resonant frequency. We observe deviations from this classical regime as the level of confinement or crowding increases and develop scaling law models to successfully describe our results. We report a difference in swimming kinematics in crowded 3D environments compared to quasi-2D. Our work reveals mechanisms for bio-inspired droplet actuation with implications for mesoscale robotics, fluidics, and sensing.

cond-mat.soft↗

arXiv2010

Performance Comparison of SVM and ANN for Handwritten Devnagari Character Recognition

Classification methods based on learning from examples have been widely applied to character recognition from the 1990s and have brought forth significant improvements of recognition accuracies. This class of methods includes statistical methods, artificial neural networks, support vector machines (SVM), multiple classifier combination, etc. In this paper, we discuss the characteristics of the some classification methods that have been successfully applied to handwritten Devnagari character recognition and results of SVM and ANNs classification method, applied on Handwritten Devnagari characters. After preprocessing the character image, we extracted shadow features, chain code histogram features, view based features and longest run features. These features are then fed to Neural classifier and in support vector machine for classification. In neural classifier, we explored three ways of combining decisions of four MLP's designed for four different features.

cs.CV↗