Rising concerns about fuel costs, emissions, oil depletion, and energy security have propelled the search for alternative energy sources in transportation. Electric vehicles are a crucial development in this direction, and fuel cell technology is gaining traction for its versatility and potential benefits. Fuel cells have become increasingly attractive for automobile owing to their ease of use, quiet operation, superior efficiency, modular design, and reliance on clean hydrogen. However, challenges remain, including hydrogen storage, high costs, integration with power electronics, and cold-start capabilities, which continue to impede the widespread adoption of Fuel Cell Electric Vehicles (FCEVs). This study critically examines these key issues, explores various fuel cell technologies and drivetrain architectures, and provides a comparative analysis of different energy storage systems. Furthermore, the study delves into the classification and evaluation of energy management strategies (EMS) for FCEVs. The review ultimately aims to stimulate further research focused on reducing costs, extending fuel cell lifespan, enhancing hydrogen infrastructure, optimizing electronic interfaces, and refining EMS to pave the way for the future of FCEVs.

The suppression of secondary electron yield (SEY) which can possibly lead to multipactor is an important goal for several applications. Though some techniques have focused on geometric modifications to lower the SEY, the use of graphene coatings as thin as a few monolayers is a promising new development that deserves attention either as a standalone technique or in concert with geometric alterations. Here we report on Monte Carlo based numerical studies of SEY on graphene coated copper with comparisons to recent experimental data. Our predicted values are generally in good agreement with reported measurements. Suppression of the secondary electron yield by as much as 50 percent (over copper) with graphene coating is predicted at energies below 125 eV, and bodes well for multipactor suppression in radio frequency applications.

We provide a simple, but physical analysis for cell irreversibility and apoptosis in response to an ultrashort (nanosecond), high-intensity electric pulse. Our approach is based on an energy landscape model for determining the temporal evolution of the configurational probability function p(q). The primary focus is on obtaining qualitative predictions of a pulse width dependence to apoptotic cell irreversibility that has been observed experimentally. The analysis couples a distributed electrical model for current flow with the Smoluchowski equation to provide self-consistent, time-dependent transmembrane voltages. The model captures the essence of the experimentally observed pulse-width dependence, and provides a possible physical picture that depends only on the electrical trigger. A number of interesting features are predicted.

The time-dependent photoconductive current response of semi-insulating GaAs is probed based on one-dimensional simulations, with a focus on the lock-on phenomenon. Our results capture most of the experimental observations. It is shown that trap-to-band impact ionization fuels local field enhancements, and photon recycling also plays an important role in pushing the device towards lock-on above a 3.5 kV/cm threshold field. The results compare well with actual data in terms of the magnitudes, the rise times, and the oscillatory behavior seen at higher currents. Moving multiple domains are predicted, and the response shown depended on the location of the photoexcitation spot relative to the electrodes.

A distributed circuit approach is used to simulate the development of electric potentials across a cell membrane and the resulting poration dynamics for ∼700 ns duration voltage pulses. Besides electric field effects, temperature increases from a pulse train are included on an equal footing to probe heating effects. The results show (i) strong heating and power dissipation at the membrane in keeping with previous simpler models, (ii) an initial spike in the membrane temperature within 100 ns timescales, (iii) a monotonic increase in membrane temperature with successive pulses to about 8 K over twelve pulses within roughly 10 μs, and (iv) large temperature gradients in excess of 2 × 107 K/m at the polar membrane region indicative of a strong source for thermo-diffusive transport. Our results suggest that inherent heating during repeated pulse application may be used to tailor excitation sequences for maximal cellular transport, broaden the permeabilization beyond the polar regions for greater transmembrane conduction, and lower the electric field thresholds for greater efficiency in longer duration irreversible electroporation protocols. More generally, the present analysis represents an initial step toward a comprehensive analysis-based optimization for tumor treatment that could select waveforms for tissues, factor in heating effects (whether for synergistic action or to ascertain safe operating limits), and engineer temporal manipulation of wavetrains to synchronize with timescales of selective bio-processes of interest for desired transient responses.

Electric pulse driven membrane poration finds applications in the fields of biomedical engineering and drug/gene delivery. Shock waves are known to permeabilize cell membranes as well. Here we focus on and analyze the synergistic effects of both inputs in concert based on molecular dynamics simulations. Our results show that shockwaves could be used for pretreating cell membranes for electroporation. The dual strategy would either reduce the external voltage requirements (leading to more compact external circuitry) or help create larger pores. Furthermore, shockwaves could form pores at any desired membrane site location, and suitable combinations of nanojets and electric pulses would help control the aspect ratio and size as desired.