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Electric-field nanobubbles: A step change in nanobubble engineering, and its "coming of age"
Niall J. English, from Chemical Engineering at University College Dublin, discusses how electric-field nanobubbles have displaced their mechanically-generated counterparts in performance and sustainability. Limited solubility of gases in water, such as oxygen, is a fundamental challenge. In ecosystems and the environment, lack of dissolved oxygen (DO) is a major reason for fish kills and water bodies being blighted by algal blooms, in addition to lack of effectiveness of activated-sludge processes in water treatment or poorer-than-hoped results in irrigation. Nanobubbles (NBs) are tiny gas bubbles on the nanometre (nm) scale. They may be thermodynamically metastable for up to many months, or sometimes even longer, and have enhanced gas-transfer properties and substantial industrial potential. The concept of NBs versus traditional, coarser bubbles – with the latter subject to buoyancy phenomena, while NBs are relatively impervious to rising – in essence, "subverts" Stokes' Law of bubble rising – and have an excellent area-to-volume ratio. If NBs are generated well – indeed, the art of "nanobubble engineering", as it were – NBs lead to important and useful applications.

Electric fields are involved in numerous physiological processes, including directional embryonic development and wound healing following injury. To study these processes in vitro and/or to harness electric field stimulation as a biophysical environmental cue for organised tissue engineering strategies various electric field stimulation systems have been developed. These systems are overall similar in design and have been shown to influence morphology, orientation, migration and phenotype of several different cell types. This review discusses different electric field stimulation setups and their effect on cell response. ; This work has been supported by Science Foundation Ireland, Career Development Award (Grant Agreement Number: 15/CDA/3629) and Science Foundation Ireland / European Regional Development Fund (Grant Agreement Number: 13/RC/2073). This work has also received funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation programme, grant agreement No. 866126. The funding agencies were not involved in the design of the study; in the data collection, analysis and interpretation; and in the writing of the manuscript. ; peer-reviewed

The anatomy of the Perpendicular Magnetic Anisotropy (PMA) in magnetic multilayered thin film heterostructures and the possibility to efficiently manipulate it by external electric fields represent major issues for technological applications in magnetic data storage devices. Solving a standard quantum model based on a Stoner-Rashba Hamiltonian, we illustrate that the magnetic properties in ultrathin magnetic films arise from the competing components identified in the magnetic energy: the Rashba correction to the Stoner splitting, a pseudo-dipolar contribution to the anisotropy energy proportional to the electric field at the interface that would favor in-plane magnetization configuration and a uniaxial-like perpendicular anisotropy term. This last term is responsible on the perpendicular magnetization configuration in ultrathin films and depends on the square of the electric field at the surface of the film. Investigating the time evolution of the magnetic system, we described the macrospin magnetization dynamics in terms of a Rashba field induced magnetization precession. Despite its simplicity, the quantum approach underlines the basic issues related to the physical origin and the mechanisms of the perpendicular magnetization in ultrathin magnetic films and illustrates the capability of manipulation by external gating electric field, in experiments similarly to Nuclear Magnetic Resonance.

1. Introduction -- 2. Field Properties -- 3. Problem Definition -- 4. Linear Spaces in Field Computations -- 5. Projection Methods in Field Computations -- 6. Finite Element Method for Interior Problems -- 7. Finite Element Method for Exterior Problems -- 8. Integral Equation Method -- 9. Static Magnetic Problem -- 10. Eddy Current Problem -- Appendix A Derivation of the Helmholtz Theorem -- Appendix B Properties of the Magnetic Vector Potential, A -- Appendix C Integral Expressions for Scalar Potential from Green's Theorem.

This paper is devoted to the investigation of an evaporation duct in the context of its impact on microwave links communication stability. The work contains the numerical results for previously developed mathematical model based on using the dyadic Green's functions. The electric field intensity dependencies on the receiving antenna suspension height and height of evaporation duct have been obtained for two variants of antenna polarization: horizontal and vertical. These results make it possible to formulate recommendations on how to place the transceiver antennas of microwave links to ensure 24-hour radio communication stability. © Published under licence by IOP Publishing Ltd. ; The work was supported by Act 211 Government of the Russian Federation, contract № 02.A03.21.0006. ; The research was executed by the grant of the Ministry of education and science of the Russian Federation (project № 8.2538.2017/4.6). ; IEEE Antennas and Propagation Society (APS)