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This research looks at the impact of dielectric fluids and fluid speeds on cell temperature control in innovative cylindrical lithium‐ion batteries during high‐rate discharges (C‐rate) using the multiscale multidomain battery model. The goal is to improve the battery thermal management system to increase battery performance, longevity, and safety. The present study includes reducing thermal strains, enhancing efficacy, and forestalling overheating risks across various applications in electrified systems. The assessment focuses on four dielectric fluids—ester, mineral, kerosene, and Novec 7200—flowing at 0.01 m/s to gauge their efficiency in managing cell temperatures. Results demonstrate the criticality of effective thermal management in maintaining optimal battery performance and longevity. Ester oil emerges as the most efficient coolant, maintaining cell temperatures at 305.84 K and showcasing a 44% reduction compared with scenarios without coolant. In contrast, kerosene oil, mineral oil, and Novec 7200 yield temperature reductions of 42.86%, 42.51%, and 43.11%, respectively. Furthermore, combining 1% v/v. MXene nanoparticles with ester oil enhance cooling capabilities, with remarkable cell temperature reductions of 50% at 0.01 m/s velocity. Subsequent increments in flow velocity lead to enhanced cooling effects: at 0.05 and 0.1 m/s, reductions reach 51.89% and 52.155%, escalating to 52.58% and 54% at 0.5 and 1.0 m/s, correspondingly. [ABSTRACT FROM AUTHOR]

The onset of convective instability in an internally heated dielectric fluid‐saturated porous layer under the influence of a uniform AC electric field for different types of boundary conditions is investigated. The flow in the porous medium is described by the Brinkman model with fluid viscosity different from effective viscosity. The lower adiabatic and the top with finite heat transfer coefficient to the external environment boundaries are considered to be either rigid or stress‐free. The presence of a uniform volumetric heat source alters the conduction profile of the temperature field from linear to quadratic in the vertical coordinate. A modal linear stability analysis of the basic motionless state is carried out and the general regime of linear instability is investigated by solving the stability eigenvalue problem numerically using the Galerkin method of weighted residual technique. The neutral stability condition as well as the critical value of the thermal Rayleigh number is computed for rigid–rigid, free–free, and rigid–free boundaries for various values of governing parameters. It is seen that the nature of boundaries affect the stability of the system only quantitatively, though not qualitatively. The rigid–rigid boundaries offer a more stabilizing effect against convection in comparison with rigid–free and free–free boundaries. The study found that the effect of increasing thermal electric Rayleigh number and the Darcy number is to hasten the onset of instability, while the opposite trend is perceived with an increase in the ratio of viscosities and Biot number. The outcomes of this investigation are found to be in good agreement with past studies under the limiting cases. [ABSTRACT FROM AUTHOR]

The role of a uniform AC electric field and a nonuniform volumetric heat source arising due to an external incident radiation on the onset of Marangoni convection in a horizontal layer of an incompressible dielectric fluid is investigated. The bottom rigid surface is fixed at a constant temperature while the top free surface at which the surface tension acts is considered to be nondeformable and a Robin boundary condition on the perturbation temperature is invoked. The nonuniform internal heating within the fluid layer alters the conduction temperature profile from linear to nonlinear in the vertical coordinate. The linear stability of the quiescent basic solution is studied with respect to normal mode disturbances. The resulting stability eigenvalue problem with variable coefficient is solved numerically using the Galerkin method. The impact of governing parameters on the instability of the system is discussed thoroughly. The forces causing instability reinforce together and are found to be tightly coupled. It is observed that the strength of nonuniform heat source and the electric Rayleigh number is to hasten, while an increase in the Biot number is to delay the onset of Marangoni electroconvection. Finally, the results obtained under the limiting cases are shown to be in good agreement with those published earlier. [ABSTRACT FROM AUTHOR]

The physico‐chemical and electrical insulating properties of certain palm oil products, including triglyceride oils, fatty acids, fatty esters, and glycerol were evaluated for use in oil‐immersed transformers. The studied triglyceride oils have excellent kinematic viscosity values: 30.25–40.49 mm2 s−1 at 40°C, 6.46–8.34 mm2 s−1 at 100°C; flash point: 278–320°C; moisture content: 16–175 mg kg−1 and dielectrical breakdown voltage: 29.1–40.9 kV. Fatty acids and fatty esters have relatively lower kinematic viscosity and flash point values than triglyceride oils. The type of hydrocarbon chain, hydrocarbon chain length and molecular size were shown to have substantial effects on the physico‐chemical and electrical properties of the studied oils. The drying process imposed on refined‐bleached‐deodorized palm olein (RBD POo) has reduced the moisture from 400 mg kg−1 to 100 mg kg−1 and improved the dielectrical strength from 31.1 kV to 76.8 kV. Blending of RBD POo with fatty acids or fatty esters has improved the kinematic viscosity of RBD POo and offers even higher flash and fire points than mineral oil. This study showed that palm oil and palm oil products have strong potential to serve as coolants and may be safer for use in oil‐filled transformers as compared to mineral oil. [ABSTRACT FROM AUTHOR]

An ultra‐wideband 1 × 4 antipodal Vivaldi antenna array with microfluidic beam steering is reported. The antipodal configuration is selected for its microstrip feed line, which is convenient for implementation of the phase‐shifting structure. Each antenna element uses a true‐time‐delay phase shifter consisting of nine microfluidic channels under its feed line in which deionized (DI) water, ɛr = 77 + j13 (tanδ = 0.17) at 3 GHz, is pumped to change the speed of the propagating wave. The array was fabricated using a 1.52 mm thick substrate with ɛr = 3.55 and tanδ = 0.0027. Each antenna element and phase shifter measures 55 mm × 140 mm. Measurements show that the array yields up to 90° of beam steering from 3 to 6.5 GHz and up to 40° of steering from 6.5 to 10 GHz. The array has a maximum realized gain of 13.1 dBi, and a half‐power beamwidth of less than 40° for all configurations. [ABSTRACT FROM AUTHOR]

We report an outbreak of irritant contact dermatitis in the aerospace industry from electrodischarge machining (EDM). 20 workers doing EDM developed irritant contact dermatitis from the dielectric fluid used in EDM. a form of precision metal machining that is widely used in mould making and precision engineering. Dielectric fluid contains hydrocarbons that are aromatic, paraffinic or naphthenic and are skin irritants. irritant contact dermatitis from dielectric fluid has not been reported previously. EDM will become more widespread and occupational dermatitis from dielectric fluid is likely to become more prevalent in the future. Our experience was that irritant contact dermatitis from dielectric fluid can be prevented by simple preventive measures such as personal hygiene and health education. [ABSTRACT FROM AUTHOR]