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Molecular-, fluid- and field-dynamics simulation are becoming more mainstream tools for practicing process engineers; here, the academic community needs to pay close attention to "upskilling" demands from industry, where remote working/training emphasizes the need for sophisticated computational-engineering design tools with molecular focus. In this integrated-simulation 'vision', spanning the molecular- to plant-design scale, it is argued herewith that academic-industry cooperation is essential to achieve progress in professional multiscale computational-engineering training, from undergraduates to practicing engineering professionals.

A novel approach for constructing a machine-learned potential energy surface (MLP) from unlabeled training data is presented. Utilizing neural networks augmented with a pool-based active learning sampling method, a potential energy surface (PES) is developed for the accurate modeling of interfaces of hematite iron oxide and water, fitting the much more expensive density functional theory (DFT). Molecular dynamics simulations were performed using this DFT-based PES to characterize the structural and energetic properties of the system. By utilizing the developed machine learning potential (MLP), it was possible to simulate much larger systems for extended periods of time, which will be important for leveraging machine learning potentials as accurate and pragmatic simulation-led molecular design and prototyping tools whilst preserving the ab initio accuracy. [ABSTRACT FROM AUTHOR]

We study the effect of static electric fields of 0.1, 0.4, and 1.0 V/nm on the hydrogen bond structure and dynamics of TIP4P/2005 water at 1 bar and at temperatures between 300 and 200 K using molecular dynamics simulations. At all these temperatures, simulating liquid water with electric fields of 0.1 and 0.4 V/nm has no additional effect on its structural and dynamical changes, which otherwise already take place due to cooling. However, the introduction of 1.0 V/nm field enhances the slowing down of liquid water dynamics, crystallizes it to cubic ice at 240 and 220 K, and amorphizes it at 200 K. At 240 and 220 K, crystallization occurs within 5 and 50 ns, respectively. An electric field of 1 V/nm increases the relaxation times in addition to what cooling does. We note that when liquid water's metastability limit is reached, crystallization is averted and amorphization takes place. Both equilibrium (liquid–solid) and non-equilibrium (liquid–amorphous) transformations are observed at 1 V/nm. Moreover, with an increase in the electric field, H-bonds become stronger. However, the donor–acceptor asymmetry (the difference between the strengths of two donor/acceptor bonds) remains even when crystallization or amorphization takes place. At low temperatures, increasing electric fields on liquid water increases both its crystallization and amorphization tendencies. [ABSTRACT FROM AUTHOR]

Nanobubbles (NBs) are gaseous domains at the nanoscale that can exist in bulk liquid or on solid surfaces. They are noteworthy for their high potential for real-world applications and their long (meta)stability. "Platform-wide" applications abound in medicine, wastewater treatment, hetero-coagulation, boundary-slip control in microfluidics, and nanoscopic cleaning. Here, we compare and contrast the industrial NB-generation performance of various types of commercial NB generators in both water-flow and submerged-in-water settings—in essence, comparing electric-field NB-generation approaches versus mechanical ones—finding that the former embodiments are superior from a variety of perspectives. It was found that the electric-field approach for NB generation surpasses traditional mechanical approaches for clean-water NB generation, especially when considering the energy running cost. In particular, more passive electric-field approaches are very operationally attractive for NB generation, where water and gas flow can be handled at little to no cost to the end operator, and/or submersible NB generators can be deployed, allowing for the use of photovoltaic approaches (with backup batteries for night-time and "low-sun" scenarios and air-/CO2-pumping paraphernalia). [ABSTRACT FROM AUTHOR]

The evolution of CO2 nanobubbles generated by gas–hydrate dissociation is comprehensively studied in this research, employing a synergistic approach that combines laboratory experiments and molecular dynamics simulations. The results show that a higher concentration of nanobubbles can be observed in the early stages of hydrate dissociation, while smaller, thus‐generated, nanobubbles are less stable and prefer to amalgamate into larger bubbles through coalescence or Ostwald ripening. From the high Laplace pressure inside some nanobubbles as well as their higher local densities, they may transform into nanodroplets by densification fluctuations. Thus, the dynamic coexistence of nanobubbles and ‐droplets is confirmed from both experimental and simulation measurements. The number and size of the nanobubbles in the system affects the interaction between water molecules and their movements so that the water molecules diffuse faster upon this condition. The water–water interactions become more pronounced in the presence of nanobubbles and the hydrogen bond network is better preserved in the bulk. This study provides new insights into the microscale mechanisms of gas–hydrate dissociation and highlights the complex interactions between nanobubbles/ ‐droplets, and the aqueous environment after CO2–hydrate dissociation. [ABSTRACT FROM AUTHOR]