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Magneto-mechano-electric (MME) generators consisting of piezoelectric and magnetostrictive materials can convert the stray magnetic noise to useful electric energy for the wireless sensor networks utilizing the magnetoelectric coupling effect and magnetic interactions. In this paper, a scalable engineering approach was proposed to fabricate the laminate MME generator composed of a PZT/Fe–Ga/PZT sandwich structure. The Goss-oriented Fe81Ga19 thin sheet with a large magnetostriction of 244 ppm was produced by a simple and low-cost approach, and the commercial polycrystalline piezoelectric ceramic products (PZT-5H) were used as the PZT layers. The effect of grain orientation, device structure, magnetic field amplitude, and resonance frequency on the electrical output of the PZT/Fe–Ga/PZT MME generator was investigated. The electrical output of the MME generator containing the Goss-oriented Fe81Ga19 thin sheet reached an AC voltage of 4.58 V and the ME coefficient of 76.33 V/cm·Oe under a low excitation magnetic field of 26 Oe at a low resonance frequency of 26 Hz. The MME generator with a Goss-oriented Fe–Ga layer shows 4.7 times higher output voltage and ME coupling coefficient than that with the no-oriented polycrystalline Fe–Ga layer, but only 81% of the latter's resonance frequency. This is related to the significant increase in magnetostriction due to the texture transition after secondary recrystallization annealing at the temperature of 950 °C. This paper provides a very promising solution to meet the self-power supply needs of the Internet of Things utilizing low-value and low-frequency magnetic fields. [ABSTRACT FROM AUTHOR]

Preparing Fe–Ga sheets with excellent magnetostrictive coefficients by rolling and annealing methods can greatly promote the development of high-efficiency magnetostrictive devices. 0.3 mm thick Fe–Ga thin sheet was produced by the one-stage large-reduction cold rolling method without intermediate annealing. Trace V and Nb elements addition improves the rolling formability of the Fe–Ga sheet by precipitating a large number of (Nb,V)C particles. The evolution of precipitation, microstructure, texture, and magnetostrictive coefficients in the Fe–Ga sheet was investigated. The microstructure of primary recrystallization is composed of homogenous distribution of fine grains with an average grain size of about 22 μm. The composite inhibitors composed of MnS and (Nb,V)C precipitates with a particle size of 40∼80 nm suppress the matrix grains effectively. The primary recrystallization texture consists of a strong γ texture with a peak at {111}<112> and a relatively strong {114}<481> texture. The secondary recrystallization of Goss grain occurs at the annealing temperature of 900 °C and is completed at 1100 °C by the combined effects of the existing inhibitor and texture. The Fe–Ga thin sheets composed of several millimeter-sized grains of Goss texture accompanied by small grains oriented by {114}<481> were obtained after annealing at 1100 °C, and its measured magnetostriction value is about 238 ppm. The present work proposes a promising routine to produce high-performance Fe–Ga thin sheets. [ABSTRACT FROM AUTHOR]

Coupled three-phase flow and reactive transport processes are widely encountered in many scientific and engineering problems. In the present study, a pore-scale model based on the lattice Boltzmann method is developed to simulate coupled three-phase flow and reactive transport processes. The model is validated by contact angle test of droplets on a curved surface and confined reactive mass transport in a three-phase system. The pore-scale model validated is then employed to study the three-phase reactive transport in channels and porous media. The evolution of the three-phase distribution, the concentration field, and the contact line length are discussed in detail. For a two-channel structure, the result shows that as the viscosity ratio increases, the phase with higher viscosity is more difficult to be displaced. Moreover, as the surface tension force between two certain phases increases, the third phase tends to form a film between the two phases, thus suppressing the reactive transport between the two phases. Finally, pore-scale simulation results of three-phase flow in a two-dimensional porous medium show that as viscosity of the phase to be displaced increases, the recovery rate of the displaced phase decreases, and the displacing phase tends to follow the mechanism of viscous fingering. Finally, while the viscosity of the displaced phase can be reduced due to the existence of the species, the recovery rate does not necessarily increase and sometimes even reduces due to the combined bypass and lubrication effects. [ABSTRACT FROM AUTHOR]

Carbon capture, utilization, and storage have been an effective way to deal with global climate issues. Injecting CO2 into depleted oil reservoirs can reach the dual goal of carbon storage and enhanced oil recovery. To optimize the gas injection strategy, it is necessary to understand the underlying mechanisms of three-phase fluid flow of oil, water, and gas. In this study, a lattice Boltzmann color gradient model is used to investigate the pore-scale three-phase displacement process in porous media. Gas is injected into the porous domain initially occupied by water and oil. Typical microscopic behaviors, including coalescence and split-up, pinch-off, double and multiple displacement, as well as parallel flow, are identified and discussed. Effects of water content (ϕ), capillary number (Ca), wettability and viscosity ratio (M) on the flow pattern, and oil recovery rate are explored. The oil ganglia inhibit the development of gas fingers, causing stronger viscous fingering characteristics with increasing ϕ. The fingering pattern is located in the crossover zone for the Ca from 5 × 10−5 to 5 × 10−4. As ϕ increases, the oil recovery rate reduces. The oil ganglia tend to occupy small pores as oil wettability enhanced, making it more difficult to be drained out. The reduction of oil viscosity is beneficial to improve connectivity, thereby effectively enhancing the oil recovery. Finally, the CO2 storage rate is also evaluated. It is found that the storage rate is very sensitive to the initial oil–water distributions. In general, the storage rate increases as ϕ decreases, Ca increases, and oil wettability enhances. [ABSTRACT FROM AUTHOR]