Transition metal selenides with high theoretical capacities possess attractive potential as anode materials of lithium ion batteries (LIBs). However, the low electrical conductivity and structural collapse caused by the large volume change upon cycling always result in poor rate capability and rapid capacity fading. In this work, binary metal selenides (ZnSe/CoSe) encapsulated in N-doped carbon polyhedra interconnected with carbon nanotubes (denoted as ZCS@NC/CNTs) are prepared through a simple solution method, involving subsequent in situ pyrolysis and selenization of the metal–organic framework (MOF) precursor at moderate temperature. Such a rational ZCS@NC/CNTs hierarchical structure provides a stable interconnected conductive network, with porous structure and shortened pathway for charge transport, synergistically enhancing the Li⁺ insertion capability. This designed ZCS@NC/CNTs exhibits high capacity, excellent rate capability and superior cycling stability. Specifically, the synthesised ZCS@NC/CNTs demonstrates a high capacity of 873 mA h g⁻¹ after 500 cycles at 0.5 A g⁻¹. More importantly, a high stable capacity of 768 mA h g⁻¹ can be retained after 1000 cycles even at a relatively high current density of 1 A g⁻¹.

Fatigue is a dominant failure mechanism of several engineering components. One technique for increasing the fatigue life is by inducing surface residual stress to inhibit crack initiation. In this review, a microstructural study under various bulk (such as severe plastic deformation) and surface mechanical treatments is detailed. The effect of individual microstructural feature, residual stress, and strain hardening on mechanical properties and fatigue crack mechanisms are discussed in detail with a focus on nickel-based superalloys. Attention is given to the gradient microstructure and interface boundary behavior for the mechanical performance. It is recommended that hybrid processes, such as shot peening (SP) followed by deep cold rolling (DCR), could enhance fatigue life. The technical and scientific understanding of microstructural features delineated here could be useful for developing materials for fatigue performance.

This paper presents a rectifier-less AC-DC energy harvesting circuit capable of harvesting energy from multiple low-voltage Piezoelectric Transducers (PETs). Synchronous electric charge extraction (SECE) technique, with bi-directional switches is adopted to achieve rectifier-less AC/DC direct conversion. The inductor is engaged only during the voltage peak of the PET output for a short period of time and therefore, a single inductor can be shared by multiple transducers. A split-capacitor charging topology is employed to harvest both positive and negative half-cycle energies, without the use of an input rectifier. In addition, a self-startup function is incorporated to kick-start the system from low input voltages. A prototype has been implemented with off-the-shelf components. Energy harvesting from three PET energy sources with different resonance frequencies is demonstrated. A peak overall power conversion efficiency of 79% is achieved with a system self-startup voltage of 650 mV.

The study investigates the role of the air–sea interface using numerical simulations of Hurricane Arthur (2014) in the Atlantic. More specifically, the present study aims to discern the role ocean surface waves and sea spray play in modulating the intensity and structure of a tropical cyclone (TC). To investigate the effects of ocean surface waves and sea spray, numerical simulations were carried out using a coupled atmosphere–wave model, whereby a sea spray microphysical model was incorporated within the coupled model. Furthermore, this study also explores how sea spray generation can be modelled using wave energy dissipation due to whitecaps; whitecaps are considered as the primary mode of spray droplets generation at hurricane intensity wind speeds. Three different numerical simulations including the sea- state-dependent momentum flux, the sea-spray-mediated heat flux, and a combination of the former two processes with the sea-spray-mediated momentum flux were conducted. The foregoing numerical simulations were evaluated against the National Data Buoy Center (NDBC) buoy and satellite altimeter measurements as well as a control simulation using an uncoupled atmosphere model. The results indicate that the model simulations were able to capture the storm track and intensity: the surface wave coupling results in a stronger TC. Moreover, it is also noted that when only spray-mediated heat fluxes are applied in conjunction with the sea-state-dependent momentum flux, they result in a slightly weaker TC, albeit stronger compared to the control simulation. However, when a spray-mediated momentum flux is applied together with spray heat fluxes, it results in a comparably stronger TC. The results presented here allude to the role surface friction plays in the intensification of a TC.