Boron nitride enhanced electric insulation paper for extending transformer thermal life
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Xu, Yue (ORCID:0000000187870153)↗
Engineering topics
Bahadur, Vaibhav
Publications and source records attributed to Bahadur, Vaibhav.
Accumulation-Driven Surfactant-Free Synthesis of Architectured Immiscible Metallic Nanoalloys with Enhanced Catalysis
Accumulation-mediated chemical reactions are a ubiquitous phenomenon in nature. In this work, we explore microbubble-induced accumulation of precursor ions to achieve surfactant-free synthesis of immiscible metallic nanoalloys and simultaneously pattern the nanoalloys into targeted architectures for their enhanced catalytic applications. Additionally, our unified spatiotemporal synthesis and structuring (US3) strategy, whereby millisecond-scale accumulation of the ions takes place in a highly confined laser-mediated microbubble trap (MBT), drives ultrafast alloy synthesis in sync with the structuring process. As a case in point, we employ the US3 strategy for the in situ surfactant-free synthesis and patterning of traditionally immiscible rhodium-gold (RhAu) nanoalloys. Stochastic random walk simulations justify the millisecond-scale accumulation process, leading to a 3-order reduction in synthesis time. The catalytic activity and structure-property relationship were evaluated using the reduction of p-nitrophenol with NaBH4. Our in situ synthesis and structuring strategy can be translated for high-throughput production and screening of multimetallic systems with tailored catalytic, optoelectronic, and magnetic functions.
36 MATERIALS SCIENCE↗
Characterizing Microfluidic Operations Underlying an Electrowetting Heat Pipe on the International Space Station
Electrowetting heat pipes (EHPs) are a newly conceptualized class of heat pipes, wherein the adiabatic wick section is replaced by electrowetting-based pumping of the condensate (as droplets) to the evaporator. Specific advantages include the ability to transport high heat loads over long distances, low thermal resistance and power consumption, and the absence of moving mechanical parts. In this work, we describe characterization of key microfluidic operations (droplet motion and splitting) underlying the EHP on the International Space Station (ISS). The testing was performed under the Advanced Passive Thermal eXperiment (APTx) project, a project to test a suite of passive thermal control devices funded by the ISS Technology Demonstration Office at NASA JSC (Johnson Space Center). A rapid manufacturing method was used to fabricate the electrowetting device on a printed circuit board. Key device-related considerations were to ensure reliability and package the experimental hardware within a confined space. Onboard the ISS, experiments were conducted to study electrowetting-based droplet motion and droplet splitting, by imaging droplet manipulation operations via pre-programmed electrical actuation sequences. An applied electric field of 36 Volts per micron resulted in droplet speeds approaching 10 millimeters per second. Droplet splitting dynamics were observed and the time required to split droplets was quantified. Droplet motion data was analyzed to estimate the contact line friction coefficient. Overall, this demonstration is the first-ever electrowetting experiment in space. The obtained results are useful for future design of the EHP and other electrowetting-based systems for microgravity applications.
Electrowetting↗