Contribution of the ventral pouch in the production of mouse ultrasonic vocalizations.

Mouse ultrasonic vocalizations (USVs) are of communicative significance and can serve as one of the major tools for behavioral phenotyping in mouse models of neurological disorders with social communication deficits. Understanding and identifying the mechanisms and role of laryngeal structures in generating USVs is crucial to understanding neural control of its production, which is likely dysfunctional in communication disorders. Although mouse USV production is accepted to be a whistle-based phenomenon, the class of whistle is debatable.

Electro-osmosis Aided Thin-Film Evaporation from a Micropillar Wick Structure.

The heat-dissipating capacity of a surface having micropillar wick structures, which resembles the evaporator section of a vapor chamber, is mainly limited by the liquid flow rate through the porous structure (permeability) and the capillary pressure gradient. The efficacy of a regular vapor chamber is determined from two parameters, namely, the dry-out heat flux and temperature of the evaporator surface. These two parameters possess a counter relation to each other.

On-Chip Concentration and Patterning of Biological Cells Using Interplay of Electrical and Thermal Fields.

We demonstrate a method of concentrating and patterning of biological cells on a chip, exploiting the confluence of electric and thermal fields, without necessitating the use of any external heating or illuminating sources. The technique simply employs two parallel plate electrodes and an insulating layer over the bottom electrode, with a drilled insulating layer for inducing localized variations in the thermal field. A strong induced electric field, in the process, penetrates through the narrow hole and generates highly nonuniform heating, which in turn, results in gradients in electrical properties and induces mobile charges to impose directional fluid flow.

Strong rotating flow in stationary droplets in low power budget using wire electrode configuration.

We explore a simple strategy of generating strong rotating flow in a stationary surface-droplet, using an intricate interplay of local electrical and thermal fields. Wire electrodes are employed to generate on-spot heating without necessitating any elaborate micro-fabrication, which causes strong local gradients in electrical properties to induce mobile charges into the droplet. Applying a low voltage (∼10 V), strong rotational velocity of the order of mm/s can be achieved in the system, within the standard operating ranges of operating and geometrical parameters.

Joule heating-induced particle manipulation on a microfluidic chip.

We develop an electrokinetic technique that continuously manipulates colloidal particles to concentrate into patterned particulate groups in an energy efficient way, by exclusive harnessing of the intrinsic Joule heating effects. Our technique exploits the alternating current electrothermal flow phenomenon which is generated due to the interaction between non-uniform electric and thermal fields. Highly non-uniform electric field generates sharp temperature gradients by generating spatially-varying Joule heat that varies along the radial direction from a concentrated point hotspot.

Alternating current electrothermal modulated moving contact line dynamics of immiscible binary fluids over patterned surfaces.

In this paper, we report the results of our numerical study on incompressible flow of a binary system of two immiscible fluids in a parallel plate capillary using alternating current electrothermal kinetics as the actuation mechanism for flow. The surfaces of the capillary are wetted with two different alternating wettability patches. The dynamic motion of the interface of the two fluids is tracked using a phase-field order parameter-based approach.

Rapid mixing with high-throughput in a semi-active semi-passive micromixer.

In this paper, we investigate a novel alternating current electrothermal (ACET) micromixer driven by a high efficiency ACET micropump. The micromixer consists of thin film asymmetric pairs of electrodes on the microgrooved channel floor and array of electrode pairs fabricated on the top wall. By connecting electrodes with AC voltage, ACET forces are induced.

Laser Calorimetry Spectroscopy for ppm-level Dissolved Gas Detection and Analysis.

In this paper we report a newly developed technique - laser calorimetry spectroscopy (LCS), which is a combination of laser absorption spectroscopy and calorimetry - for the detection of gases dissolved in liquids. The technique involves determination of concentration of a dissolved gas by irradiating the liquid with light of a wavelength where the gas absorbs, and measuring the temperature change caused by the absorbance. Conventionally, detection of dissolved gases with sufficient sensitivity and specificity was done by first extracting the gases from the liquid and then analyzing the gases using techniques such as gas chromatography.