Ammonia is considered as one of the promising hydrogen carriers toward a sustainable world. Plasma assisted decomposition of NH 3 could provide cost-and energy-effective, lowtemperature, on-demand (partial) cracking of NH 3 into H 2 . Here, we presented a temperature-dependent plasma-chemical kinetic study to investigate the role of both electron-induced reactions and thermally induced reactions on the decomposition of NH 3 . We employed a plasma-chemical kinetic model (KAUSTKin), developed a plasmachemical reaction mechanism for the numerical analysis, and introduced a temperature-controlled dielectric barrier discharge reactor for the experimental investigation using 1 mol % NH 3 diluted in N 2 . As a result, we observed the plasma significantly lowered the cracking temperature and found that the plasma-chemical mechanism should be further improved to better predict the experiment. The commonly used rates for the key NH 3 pyrolysis reaction (NH 3 + M ↔ NH 2 + H + M) significantly overpredicted the recombination rate at temperatures below 600 K. Furthermore, the other identified shortcomings in the available data are (i) thermal hydrazine chemistry, (ii) electron-scattering cross-section data of N x H y , (iii) electron-impact dissociation of N 2 , and (iv) dissociative quenching of excited states of N 2 . We believe that the present study will spark fundamental interest to address these shortcomings and contribute to technical advancements in plasma assisted NH 3 cracking technology.

The effects of pressure on the characteristics of lifted flames in a coflow with propane fuel were investigated experimentally in a pressure chamber. Changing the pressure influenced the density, reaction kinetics, and flame propagation speed. The pressure range tested was P = 0.55.5 atm. As the fuel jet velocity increased, a nozzle-attached flame transitioned to a lifted flame before blowout occurred. Depending on pressure, the onset conditions of liftoff and blowout occurred in the laminar, transition, or turbulent regimes. When P < 1.6 atm, the flame was lifted and had a tribrachial edge structure in the laminar regime, and the liftoff height (HL) increased with increasing pressure. Both the liftoff and blowout velocities decreased with decreasing pressure, and they merged at 0.5 atm. A correlation was derived in terms of the Schmidt number (Sc) and the Reynolds number (Re): / / ()/() ∝ Re. The reattachment velocity in the laminar and transition regimes linearly decreased with pressure. The liftoff height had two local minimum points at a given Reynolds number in the transition regime, and then increased linearly in the turbulent regime.

Biological nanomachines, including proteins and nucleic acids whose function is activated by conformational changes, are involved in every biological process, in which their dynamic and responsive behaviors are controlled by supramolecular recognition. The development of artificial nanomachines that mimic the biological functions for potential application as therapeutics is emerging; however, it is still limited to the lower hierarchical level of the molecular components. In this work, we report a synthetic machinery nanostructure in which actuatable molecular components are integrated into a hierarchical nanomaterial in response to external stimuli to regulate biological functions. Two nanometers core-sized gold nanoparticles are covered with ligand layers as actuatable components, whose folding/unfolding motional response to the cellular environment enables the direct penetration of the nanoparticles across the cellular membrane to disrupt intracellular organelles. Furthermore, the pH-responsive conformational movements of the molecular components can induce the apoptosis of cancer cells. This strategy based on the mechanical motion of molecular components on a hierarchical nanocluster would be useful to design biomimetic nanotoxins.