D. Banerjee
Texas A&M University,
United States
Keywords: TBD
Summary:
We are leveraging bio/micro/nano-technologies for augmenting bio-sensing, cooling, energy storage and safety systems (involving both experimental and computational studies). Using surface nano-coatings, (such as: silicon nano-fins and Carbon-Nanotube [CNT]) coupled with temperature nano-sensors (thin film thermocouples/ TFT and diode nano-sensors), deviant levels of cooling enhancement were achieved, especially for those with lower thermal conductivity. Nanofluids: Augmented energy storage was achieved on doping nanoparticles into fluids (nanofluids), especially for nanoparticles with lower specific heat capacity than the solvent. Specific heat capacity was enhanced by ~120% for nanofluids. Deviant density enhancement of ~10% was also achieved. This has applications in radiation mitigation (e.g., astronaut health protection), drug delivery, diagnostics and energy technologies, such as: oil and gas (hydraulic-fracturing). Microchannel experiments using nanofluids showed that the precipitated nanoparticles behaved as nanofins (enhanced surface area) that dominate heat transfer for micro/nanoscale flows – because of the “nano-Fin Effect” (nFE). These “accidental discoveries” in the Banerjee research group led to pioneering the term: “nFE” (i.e., due to dominance of interfacial thermal-impedances at the nano-scale, e.g., resistance, capacitance and diode effects) [US Patent 10220410]. Lab-on-Chip (LoC): Fluid phase transitions in nanoscale pores is a challenging problem that is significant for various applications, such as drug delivery, carbon dioxide storage (sequestration), and enhanced oil recovery. Experimental validation of numerical predictions were performed by leveraging lab-on-a-chip technology (LOC) that was integrated with high-resolution imaging (confocal microscopy) for investigating the phase behavior of hydrocarbons inside nanoscale capillaries (nanochannels). The results show that dewpoint pressure of hydrocarbons can deviate by 14% due to the “confinement effect” which is another manifestation of nFE. The results from our studies show that the fluid confinement has a significate effect on alteration of hydrocarbon phase behavior by increasing the bubble point temperature, especially for nanopores with diameters less than 10 nm. For the first time, we presented the direct observation and visualization of vapor–liquid phase transitions of hydrocarbons in a 2 nm slit pore using LOC technology which enabled the direct visual observation of many nanoscale phenomena. For the first time we experimentally measured and directly visualized the deviation of the vapor−liquid phase transition pressure in a 2 nm slit pore compared to the associated unconfined or bulk value (leading to hysteresis). DPN™ (Dip Pen Nanolithography™) leverages Scanning Probe Microscopy using microfluidics. Commercial microfluidic devices called “Inkwells™” were developed earlier. The next generation microfluidic devices are being developed for DPN (e.g., Fountain Pen Nanolithography, “centiwells”). The applications are in bio-nanotechnology, and nano-sensors for homeland security and explosives detection (“nano-nose”). By leveraging DPN techniques, we invented a gasless process for synthesis of nanoparticles (e.g., graphene, CNT, etc.) under ambient conditions with synthesis temperature less than 300 °C [US Patent 8470285].