Polydopamine-assisted aramid nanofiber/exfoliated graphite hybrid films with high mechanical strength, thermal stability, Joule heating, and EMI shielding performance

Thermal and roto-hydrodynamics behaviors of Fe3O4-based ferrofluid under magnetohydrodynamic flow and Joule heating in a sliding fillet chamber

A linear, decoupled and unconditionally stable scheme for the thermally coupled incompressible magnetohydrodynamic flow including Joule heating and dissipative heating

Flash Joule heating for converting plastic waste to graphene: Effects of precursor compression on yield and quality

Interfacial polarization-dominated electromagnetic attenuation in biomass-origin porous carbon materials.

Developing flexible electronic materials that integrate high strength, electrical insulation, and reliable sensing remains challenging. This is because the void structures inherent in nanocomposite films significantly compromise their mechanical performance and functionality. This study systematically investigates the influence of calcium sulfate crystallite (CSC) dimensions and content on the void structure, mechanical properties, and functional characteristics of aramid nanofiber (ANF) composite films via the incorporation of CSCs into the ANF matrix. The underlying mechanisms governing these effects were thoroughly examined. CSCs with different dimensions were first synthesized via a hydrothermal method. Then, ANF/CSC composite films were fabricated through a sequential process of vacuum-assisted filtration followed by hot-pressing. The results indicate that the composite film incorporating medium-sized CSCs at 30 wt% exhibits the optimal reinforcement effect, achieving a tensile strength of 177.7 MPa, which represents a 289% improvement compared to the pristine ANF film. It was found that the CSCs form a three-dimensional network architecture within the ANF matrix, which effectively fills the voids and enhances the degree of orientation. Furthermore, a Janus-structured ANF/CSC-ANF/AgNW film was constructed, achieving the integration of electrical insulation on one side and conductivity on the other. The sample containing 30 wt% AgNWs exhibited rapid Joule heating, reaching 110 °C within 10 seconds under an applied voltage of 10 V. Moreover, it maintained stable electrical performance even after 750 bending cycles in sensing tests. This study provides a strategy to effectively enhance the mechanical and insulating properties of composite materials through a three-dimensional network of CSCs and ANFs and achieves integrated assembly of an insulating substrate and a conductive sensing layer by introducing a Janus structure. It offers greater possibilities for the application of high-performance flexible electronic devices in extreme environments.

This paper presents a comprehensive analysis of magnetohydrodynamic (MHD) flow, radiative heat transfer, and mass transport in nanofluids interacting with an incompressible, electrically conducting fluid. The study accounts for the combined effects of Joule heating, viscous dissipation, and a first-order chemical reaction over a porous plate embedded in a porous medium subjected to a prescribed heat flux. A numerical investigation is performed on the boundary-layer flow model involving three distinct nanoparticle types Cu , A l 2 O 3 and Ag . The governing equations for momentum, energy, and species concentration are formulated under the boundary-layer approximation. By employing similarity transformations, the coupled nonlinear partial differential equations with associated boundary conditions are reduced to a system of ordinary differential equations (ODEs) defined over a semi-infinite domain. This system is solved numerically using a hybrid scheme that integrates the Shooting technique with the fourth-order Adams–Moulton method. The accuracy of the results is confirmed through comparison with previously published data, demonstrating excellent agreement. The effects of key physical parameters on the velocity, temperature, and concentration fields are examined and illustrated through graphical and tabular analyses. Furthermore, thermophysical property correlations are provided. The findings indicate that an increase in nanoparticle volume fraction leads to elevated temperature profiles, thereby enhancing the Schmidt number. Thus, the results provide a clear understanding of fluid flow behaviour in applications such as nuclear reactor cooling systems, polymer extrusion processes, and electromagnetic magnetohydrodynamic generators.

Sustainable batteries necessitate high-performance hard carbon negative electrodes derived from abundant biomass. However, realizing their full potential is significantly limited by the inherent diversity of biomass feedstocks, the intricate control over carbonization and resulting microstructures, and the complex interplay between processing, structure, and electrochemical performance. Here, we introduce "intelligent carbonization", a strategy integrating programmable Joule heating (1000-2000 °C, 10-60 s) with machine learning to substantially accelerate the discovery and optimization of biomass-derived hard carbons. By mapping over 1000 synthetic pathways and decoding the multidimensional feature space, we reveal a performance-correlated factor that serves as a crucial predictor of capacity, complementing conventional graphitic descriptors (in-plane crystallite size/ interlayer spacing). By a minimal energy input (0.1 kWh g-1), our strategy converts biochar into advanced hard carbon delivering 369 mAh g-1 reversible capacity, high rate capability, and improved cycling stability (>5000 cycles at a specific current of 3 A g-1). This data-centric approach allows low-cost and intelligent manufacturing of diverse biomass resources into performance-unified hard carbon negative electrodes, thereby paving the way for practical and large-scale biomass valorization towards sustainable energy storage solutions.

Conventional conductive elastomeric composites, consisting of conductive fillers dispersed in elastomers, are widely used in soft electronics for strain sensing via resistance changes arising from filler separation during elongation. However, they often exhibit substantial performance degradation under large strains. Liquid metals (LMs) have recently attracted significant attention owing to their unique fusion of metallic conductivity and fluidic properties. Here, we develop sheath-core fibers featuring a magnetic LM (MLM) core, formed by embedding Fe particles into eutectic gallium-indium alloy (EGaIn) dispersed in thermoplastic polyurethane (TPU), and coaxially wet-spun with an insulating TPU sheath. Subsequently, these MLM/TPU fibers are woven into horizontally and vertically interlaced textiles. This wet-spinning process, coupled with post-freeze-pressure activation, fuses Fe-EGaIn droplets into percolating networks, yielding exceptional conductivity (3.9 × 104Sm-1), extreme stretchability (482% elongation), and strain-invariant resistance ( - 6% at 100% strain). Particularly at 7 wt% Fe, the MLM/TPU composite serves as a magnetically responsive, reconfigurable conductor that enables tunable Joule heating (reaching 75.8°C at 1.2V), infrared stealth, and magnetically driven remote switching, while promoting absorption-dominated electromagnetic interference (EMI) shielding (33.82dB with an absorptivity of 0.520). This study offers substantial promise for applications in wearable electronics, soft robotics, and EMI-shielding textiles.

Microfluidic electroporation for drug and gene delivery: Driving innovation from single-cell precision to high-throughput preclinical and therapeutic platforms.

The rapid progress in electronics has exacerbated electromagnetic pollution, escalating the demand for electromagnetic interference (EMI) shielding materials. Whereas the abandonment of conventional nonbiodegradable EMI materials further provoked environmental pollution. Consequently, there is a growing emphasis on the biodegradability of EMI materials, in addition to qualities such as strong absorption, lightweight, flexibility, and breathability. In this study, biodegradable ultrafine fibrous EMI shielding mats were developed from epoxy-modified corn protein zein (ZE) with single- or double-layer coatings of polypyrrole (PPy) and silver (Ag). The epoxy modification endowed the base ZE fibers with adequate mechanical properties and morphological stability in wet conditions, ensuring high air permeability. The PPy/ZE mats achieved an EMI shielding effectiveness (SE) of 26.69 dB within the 8.2 to 12.4 GHz frequency range, which was further boosted to 86.00 dB by the Ag/PPy/ZE mats. Even after 5000 bends, 86.5% and 79.3% of the SE values could be retained. The Ag/PPy/ZE mats demonstrated antibacterial properties and adjustable joule heating performance. Biodegradation was evident after 40 days of soil burial, characterized by near-linear weight loss and alterations in mechanical properties. This study positions the Ag/PPy/ZE mats as a promising option for short-term EMI shielding in electronic devices or biomedical applications, both in vitro and in vivo, thereby stimulating the advancement of biobased EMI shielding materials.

High-temperature capacitive energy storage demands dielectric polymers that integrate high thermal conductivity with excellent electrical insulation to mitigate thermal runaway induced by Joule heating. However, conventional strategies for improving thermal conductivity through increased aromatic conjugation frequently exacerbate conductive losses under elevated temperatures and high electric fields. To resolve this fundamental trade-off between thermal conductivity and electrical insulation, we introduce a conjugation-decoupling strategy. This approach incorporates aliphatic segments to disrupt the π–π conjugation networks, implemented through a machine learning-assisted co-design workflow. A transfer learning model is built to establish the structure–property relationship between glass transition temperature and thermal conductivity, and subsequently guides the synthesis of three semi-aromatic polyimides that concurrently achieve a high glass transition temperature, a wide bandgap, and high thermal conductivity. The resulting semi-alicyclic polyimide film demonstrated outstanding discharge energy density (5.26 J cm−3) and η = 90% performance at 200 °C, significantly outperforming commercial Kapton polyimide film. We report a strategy for high-temperature dielectric development using an interpretable machine learning model, demonstrating a concurrent enhancement of electrical insulation and thermal conductivity, properties typically constrained by a conventional trade-off.

ABSTRACT Engineered tissues are widely used to replicate and restore biological structures; however, their functionality critically depends on high cell survival. Cell viability is often compromised when tissues are handled or stored outside controlled environments due to temperature fluctuations and nutrient depletion. While incubators can mitigate these limitations, maintaining stable conditions during handling and transport remains challenging. To address this challenge, we introduce a hydrogel‐based tissue engineering scaffold with integrated thermoregulation and nutrient delivery. The scaffold is based on granular hydrogels whose interstitial spaces are functionalized with the conductive polymer poly(3,4‐ethylenedioxythiophene) polystyrene sulfonate (PEDOT:PSS), which imparts electronic conductivity, while Zn 2 + ions enhance ionic conductivity. These additives enable Joule heating, providing control over the substrate temperature. Continuous passive nutrient delivery is achieved by functionalizing the substrate with cell media–loaded polyelectrolyte microfragments. This hydrogel‐based platform sustains homeostatic conditions without the need for external incubators, improving cell viability and resilience, which is key, for example, for point‐of‐care testing and personalized medicine.

To enhance the thermal management capabilities of epoxy composite, inspired by Baumkuchen, a simple, scalable, and environmentally friendly process was proposed. The graphene strips, without any chemical modification, were integrated into assembled graphene paper, and the vertically aligned graphene strips/epoxy composite with the tree-ring structure was prepared by the rolling cutting method. The composite exhibited an extremely high through-plane thermal conductivity of 49.2 W/mK, which was 289 times higher than that of pure EP. Additionally, the composite also possesses a range of desirable properties, including good electromagnetic interference shielding, efficient Joule heating, and remarkable mechanical performance. These properties further expand the application of graphene-based thermal interface materials in the field of thermal management of electronic devices.

Abstract The offset between Earth's magnetic and rotational axes introduces a diurnal dependence in the high‐latitude EUV exposure of the northern hemisphere (NH) and southern hemisphere (SH). This variation raises the question: Does the Universal Time (UT) of geomagnetic storm onset impact its geospace consequences? To address this question, we used the Multiscale Atmosphere‐Geospace Environment (MAGE) model to simulate the 10 October 2024, geomagnetic storm—the year's second strongest (SYM‐H minimum of −346 nT). Since the storm occurred near equinox, we did not expect, but found, significant interhemispheric asymmetries in magnetosphere‐ionosphere‐thermosphere (M‐I‐T) coupling parameters such as the cross‐polar cap potential, hemispherically integrated field‐aligned current, and hemispheric power of electron precipitation. Controlled simulations show that interplanetary magnetic field (IMF) and solar wind have negligible effects on these asymmetries, whereas the EUV variation arising from the diurnal dipole tilt produces noticeable interhemispheric differences. Coincidentally, during this storm, IMF B z turned southward when the SH was tilted toward the Sun, and it maintained this orientation for 12 hr. A controlled simulation with storm onset shifted by 12 hr exhibits a substantial reduction in interhemispheric asymmetry. Differences in integrated Joule heating power and the SML/SMU indices also occurred with the shifted onset, underscoring the importance of UT in stormtime magnetosphere‐ionosphere coupling.

Enhancing the heat and mass transfer performance of working fluids remains a critical challenge to pursue sustainable and energy-efficient technologies. Although regular working fluids have superior thermo-physical properties to pure base fluids, they often face limitations that hinder their adoption in multifunctional applications. To overcome these challenges, this study develops a novel, comprehensive and physically consistent mathematical model for an unsteady, electrically conducting ternary hybrid nanofluid composed of graphene oxide (GO), cerium oxide (CeO[Formula: see text], and hexagonal boron nitride ([Formula: see text]-BN) suspended in an environmentally friendly ionic liquid (Ethyl-3-methylimidazolium tetrafluoroborate) [EMIM][BF 4 ]. The model integrates magnetic effects, radiation heat transfer, viscous dissipation, Joule heating, and coupled thermo-diffusion effects. A fractal–fractional derivative operator is employed to generalize the governing equations, while the local radial basis functions (RBF) scheme is used to solve them numerically. Computational and graphical results reveal that CeO 2 suppresses the fluid velocity due to increased inertial resistance, while the dispersion of [Formula: see text]-BN significantly enhanced the thermal profile, resulting in a higher Nusselt number. Furthermore, higher values of Dufour and Soret numbers enhance the coupled heat and mass transfer rates, indicating the model’s potential to design advanced heat exchangers and smart cooling devices. These findings provide valuable guidelines for designing compact heat exchangers and thermal energy storage systems for applications in renewable energy and microelectronics cooling.

This study undertakes a detailed examination of steady, two-dimensional boundary layer flow of a tangent hyperbolic nanofluid past a stretching sheet embedded within a porous medium, subjected to the action of a transverse magnetic field. The mathematical formulation accounts for the effects of velocity slip, viscous dissipation, Joule (Ohmic) heating, first-order homogeneous chemical reactions and wall heat transfer governed by Newtonian convective cooling. Furthermore, the thermodynamic irreversibilities resulting from fluid friction, heat transport and magnetic field effects are evaluated by entropy production and Bejan number analyses. While previous studies have examined Newtonian and conventional non-Newtonian nanofluid flows, the combined influence of electromagnetic forces, non-Newtonian rheology, slip mechanisms, reactive transport, convective thermal conditions and thermodynamic irreversibility for tangent hyperbolic nanofluids remains largely unexplored—a gap addressed in this work. The governing partial differential equations are reduced to a system of ordinary differential equations through similarity transformations and solved numerically using both the three-stage Lobatto IIIa collocation scheme ( bvp4c in MATLAB) and the shooting method with a classical fourth-order Runge–Kutta algorithm. The findings reveal that higher Eckert number ( Ec ) values lead to a substantial reduction in the Nusselt number by 18.3%–53% due to intensified viscous dissipation, but cause a moderate increase in the Sherwood number by 0.5%–1.5%. From the thermodynamic perspective, entropy generation increases with increasing Eckert number and Joule heating parameter and rises with higher chemical reaction parameter and Biot number as well. These patterns offer helpful recommendations for reducing losses and improving thermal efficiency in procedures including biofluid transport and polymer extrusion.

Abstract Current-carrying wear is a complex multi-physics coupled phenomenon in electrical contact systems, involving the interaction of mechanical friction, current conduction, and thermal effects, which critically affects the operational reliability of electrical devices. This study presents a systematic investigation of the wear behavior of a QCr0.5 chromium bronze/1080 steel friction pair under current-carrying conditions, integrating experimental measurements with numerical simulations. A multi-physics finite element model was developed within a coupled mechanical-thermal-electrical field framework, incorporating temperature-dependent material properties, definitions of thermal and electrical contact pairs, integration of friction heat and Joule heat, and calculations of friction force and wear rate. Orthogonally designed experiments under varying loads, current intensities, and sliding speeds were conducted to validate the model's predictive capability for multi-physics coupling. The results demonstrated a maximum error of 17.98% and an average error of 11.07% in wear rate prediction, indicating acceptable accuracy. A detailed analysis of worn surface morphology, combined with simulated wear depth and temperature distributions, systematically identifies the dominant wear mechanisms under different degrees of current influence. The findings reveal that under relatively weak influence of current, the dominant wear mechanisms remain mechanical, including abrasive and adhesive wear. However, under relatively strong influence of current, thermal effects such as Joule heat, friction heat, and potential arc melting lead to material softening, and a transition to electrical-mechanical coupled wear mechanisms. This study introduces a novel multi-physics coupling modeling and numerical simulation framework to investigate current-carrying wear behavior, providing a foundation for the optimization of electrical contact systems.

To quantitatively elucidate the effects of overload current on the ignition and burning hazards of polyethylene-insulated wires, 2.5 mm2 polyethylene-insulated copper wires used commercially were tested in an electrical fire fault simulation system. Experiments were conducted to study the evolution of overloads, ignition, and burning. The entire process, from insulation smoking and ignition to sustained burning and final extinction driven by wire fusing, was recorded using synchronized digital and high-speed imaging. Video-based measurements were used to extract the following: smoking emission duration, ignition time, burning duration, maximum flame height, and segmented flame width. The results show that stable ignition and sustained burning occur when the overload current is greater than or equal to 180 A. As the current increases, ignition occurs earlier, while the smoking stage becomes shorter but exhibits nonmonotonic fluctuations. The burning duration shows a staged response. It first increases, then decreases toward a relatively stable level. This reflects the competition between enhanced Joule heating and accelerated wire melting and fusing. Maximum flame height and segmented flame width vary nonmonotonically with current, and the segmented flame width peaks at 200 A. A multi-indicator fire hazard evaluation framework was established and an entropy-weight TOPSIS method was applied to integrate the quantification and ranking. The overall fire hazard is greatest at 200 A. These findings provide experimental insight into overload-induced ignition and combustion behavior and contribute to a quantitative understanding of fire hazard evolution in overloaded electrical wires.

High-entropy alloy nanoparticles (HEA-NPs) have garnered significant interest across diverse fields. However, thus far, research on their applications has predominantly focused on electrocatalysis. Expanding the applications of HEA-NPs beyond current fields is timely and desirable but remains a challenge. Here, we demonstrate the successful femtosecond laser synthesis of HEA-NPs on the laser-induced graphene (LIG) for realizing high-performance Joule heating applications. This prepared composites (HEAs/LIG) exhibits exceptional electrothermal conversion ability with efficiency up to ~285.4 °C cm2 W-1. Furthermore, the HEAs/LIG also shows high broadband infrared emissivity of ~0.98 across the wavelength range from 2.5 to 20 μm. Finally, we present the applications of HEAs/LIG as an efficient Joule heater, which consumes ~49.1% less energy compared to conventional electrical heaters in winter. This work expands the application of HEA-NPs into the Joule heating field, and underlining the importance of further development in efficient energy utilization technology.