The aim of this study is to evaluate the performance of commonly used RANS turbulence models in the context of heat generating liquids of moderately low Prandtl numbers of 0.1 and 0.2. This situation is of particular interest in the context of novel nuclear reactors using liquid metal fuels, such as the prototypical Dual Fluid Reactor described for example in ( Arnold et al., 2025 ; Sierchuła et al., 2019 ; Weissbach et al., 2020 ). This reactor uses a liquid metal coolant (Lead) and a liquid metal fuel (Uranium-Chromium eutectic) in two separate circuits. This concept can be considered as a mixture of a molten salt reactor and a lead cooled fast reactor. The liquid metal fuel and -coolant allow a fast neutron spectrum as well as high operating temperatures. The liquid fuel enables continuous online reprocessing and also offers the possibility to implement passive safety systems such as subcritical drain tanks. The current study investigates fundamental thermal-hydraulics of a triangular-lattice rod bundle arrangement with a pitch-to-diameter ratio of 1.4. The focus lies on the low Reynolds number regime of flows ( Re ≤ 5000), which is of particular interest in case of natural circulation. Since the streamwise- as well as the crossflow direction are widely used and in their nature quite different, both situations are analysed. The study is performed using the Nek5000 DNS code as well as the Ansys Fluent code, which was used for RANS simulations. The investigated Prandtl numbers of 0.1 and 0.2 were selected since they are the highest and lowest Prandtl numbers expected to occur in the liquid fuel of the dual fluid reactor studied in ( Arnold et al., 2025 ). The DNS results are compared with two RANS models, namely the 7-equation Reynolds stress model (RSM BSL) and the 2-equation k-omega-SST model. • DNS and RANS simulations of a rod bundle were performed at low- to intermediate Reynolds numbers for streamwise and crossflow conditions. • Prandtl numbers of 0.1 and 0.2 were used to investigate the effects of heat transfer in this sparsely studied range of Prandtl numbers. • k-omega-SST and RSM-BSL models were found to be in reasonable or even good agreement with the DNS data, however, further simulations are found to be necessary.

Numerical simulation on the flow and heat transfer of liquid lithium metal within triangular wire rod bundle channels

Enhanced liquid metal embrittlement and its tempering‑temperature dependence in the fatigue crack growth of T91 steel exposed to lead–bismuth environment

Liquid metal particles as versatile building blocks: fabrication, design principles, and multifunctional applications

Lubrication behavior and mechanisms of gallium-based liquid metal under simulated space proton irradiation

This study investigates the linear stability of natural convection of liquid metals in a vertically mounted annular enclosure subjected to an azimuthal static magnetic field. While previous studies have demonstrated the stabilizing influence of magnetic fields for specific fluid properties, the role of the Prandtl number (Pr) in the transition from an axisymmetric steady state to three-dimensional flow structures has not yet been fully clarified. To address this issue, a systematic linear stability analysis is conducted over a wide range of Prandtl numbers (Pr = 0.005–0.05), with the Rayleigh number (Ra) and the Hartmann number (Ha) as governing parameters. The results reveal that the critical Hartmann number (Hac), which defines the stability threshold, exhibits a strong negative correlation with Pr. To generalize this stability threshold, a unified correlation equation for Hac was formulated using the Churchill–Usagi method, successfully blending the distinct asymptotic scaling laws identified for the low- and high-Pr regimes. The proposed correlation demonstrates excellent agreement with the numerical data, confirmed by a parity plot yielding a coefficient of determination of 0.9592. These findings provide new insights into mode selection and instability mechanisms in low-Prandtl-number magnetohydrodynamic convection, with direct relevance to applications such as crystal growth and fusion reactor engineering.

Ultrasonically-actuated liquid metal gallium micromotors with patterned ultrasound transducers

Corrosion risks of mercury pollution and contamination: Economic, ecological, and safety perspectives.

Flexible fiber capacitive tactile sensors hold promise for wearable human-machine interaction, yet balancing sensitivity with robustness while preserving textile softness remains challenging. To mitigate this trade-off, a capacitive tactile fiber based on the dual-mechanism enhancement of gradient-porous compression and Maxwell-Wagner interfacial polarization was developed. A fiber with a radial gradient-porous architecture, comprising a liquid metal (LM)/thermoplastic polyurethane (TPU) conductive core and a titanium dioxide (TiO2)/TPU dielectric sheath, was fabricated via coaxial wet spinning through non-solvent induced phase separation. A sub-percolating carbon nanotube/graphene oxide (CNT/GO) network was subsequently introduced onto the fiber surface to amplify the effective permittivity via interfacial charge accumulation. A sensitivity of 18.32 kPa-1, a response time of 170 ms, a hysteresis error of 4.47%, and stable signal retention over 1000 cycles were achieved. An all-textile wireless tactile platform was constructed and progressively validated from transient mouse clicking to quasi-static sitting posture monitoring (99.6% recognition accuracy) and further to a 64-key textile keyboard, where signal crosstalk was effectively decoupled through a fabric topology design and a one-dimensional convolutional neural network algorithm, yielding a character recognition accuracy of 96.36% and enabling context-aware generative artificial intelligence communication via integration with a large language model. This work demonstrates the significant potential of fiber-based tactile sensors for complex, multi-scenario human-machine interactions and provides new insights into the development of next-generation intelligent textile interaction platforms.

Owing to the high surface tension, gallium-based liquid metals are difficult to stably deposit via direct writing while maintaining high pattern fidelity, posing a challenge for their patterning into high-precision flexible conductive circuits. In this work, a Ga-Al-Mg ternary liquid metal alloy (LMA) was prepared through trace alloying with magnesium and aluminum. With the introduction of 0.6 wt % Al and 0.4 wt % Mg into liquid gallium, the resulting LMA64 achieved a favorable balance among wettability, shear-thinning behavior, low-frequency viscoelasticity, and apparent yield stress, enabling stable direct writing of conductive traces with a minimum line width of approximately 200 μm. Compared with pure gallium, LMA64 reduced the contact angle from 148.5 to 115.5°, while increasing the normalized shear-thinning factor and apparent yield stress to 2.43 and 1.77 times those of pure Ga, respectively. Furthermore, the printed LMA64 circuits exhibited chemical reactivity toward aqueous solutions and, notably, underwent rapid reaction and circuit disconnection in acidic aqueous environments. Leveraging this property, we constructed a wearable patch-type alarm sensor for wound-fluid-triggered monitoring. The integrated sensor produced an alarm response within approximately 2 s upon contact of the circuit with an aqueous solution. In addition, a multilayer moisture-buffering structure helped suppress interference from sweat and ambient humidity during routine wear, rendering the device more suitable for monitoring scenarios involving large-volume body fluid leakage. The wearable patch also features simple fabrication, replaceable sensing components, and recyclability of gallium metal, demonstrating promising potential for postoperative wound monitoring, abnormal exudate warning, and low-cost disposable wearable alarm devices.

Generation IV prismatic high-temperature gas-cooled reactors (PHTGRs) require coupled thermal-hydraulic and neutronic analysis to characterize safety margins, yet explicit resolution of TRistructural ISOtropic (TRISO) particles in computational fluid dynamics (CFD) remains computationally prohibitive. Standard homogenization approaches are efficient, but they do not directly provide the intraparticle temperature information needed for accurate Doppler feedback evaluation. To address this, this study develops a multiscale coupling framework that combines Serpent Monte Carlo neutronics, OpenFOAM CFD, and a dedicated analytical heat conduction solver. In the proposed approach, the fuel compact is treated as homogeneous in the CFD solution, while TRISO coating layer and kernel temperature profiles are analytically reconstructed for each CFD fuel cell from the homogenized compact temperature field and supplied to the neutronics for cross-section evaluation. Compared with recently reported Serpent-OpenFOAM applications to research reactors, small modular reactors, molten salt reactors, liquid metal–cooled reactors, and light water reactors, the present work focuses on a PHTGR with TRISO fuel and distinguishes itself through full integration with Serpent’s unstructured mesh coupling interface and a per cell analytical reconstruction of TRISO temperatures within a block-scale Monte Carlo/CFD framework. The coupling approach is applied to a high-temperature engineering test reactor–based fuel block model, where the coupled simulation resolves intrablock power peaking, absorber proximity effects, and subpin radial power and temperature variations, predicting a maximum fuel rod temperature of 1249 K and a coolant outlet temperature of 950 K. The results show that the framework provides high-resolution thermal feedback information for PHTGR analysis without the prohibitive cost of explicit TRISO meshing and can serve as a high-fidelity reference tool for validation of lower-order system models.

Liquid metals (LMs) represent a novel category of functional materials characterized by low melting points, metallic conductivity, and distinctive fluidic behavior. In contrast to traditional metals, LMs exhibit a combination of mechanical flexibility alongside superior electrical conductivity and thermal properties, rendering them highly suitable for biomedical applications. Ga-based LMs, in particular, have attracted significant interest due to their favorable biocompatibility and chemical stability, effectively addressing the toxicity concerns associated with mercury. In the context of tumor diagnosis, their elevated X-ray attenuation coefficients and facile surface modification capabilities enable their use as contrast-enhancing agents in X-ray imaging, computed tomography, and photoacoustic imaging modalities. Therapeutically, Ga-based LMs have been investigated for their potential as antimicrobial agents, drug delivery vehicles, and multifunctional composites in cancer treatment. Taken together, the combination of deformability, electrical conductivity, and biocompatibility underscores the potential of LMs as promising candidates for next-generation theranostic platforms. This review provides an overview of the fundamental properties of LMs and discusses recent progress in their application for tumor diagnosis and therapy.

High-speed continuous fluids transport within enclosed pipelines is a core driving technology in biomedicine, chemical analysis, and soft robotics. However, conventional pumping technologies rely on bulky compressors that suffer from excessive power consumption (>3 × 107 W), high noise (>60 dB), and considerable weight (>2 kg). Although emerging liquid metal (LM)-based micropumps offer silent and portable alternatives, the inherent clogging of chambers by deformed LM restricts operation to the high frequency (>100 Hz) and low duty cycle (<50%) of the electrical signal, inevitably leading to flow rate decay (<5000 μL min-1). Herein, we introduce a magnetic LM-based electro-magnetic fluid pump (mEMFP) that synergizes electric and magnetic fields for efficient liquid transport. By integrating core-shell Fe@PDA@Ag magnetic particles into LM, we generate magnetically responsive LM droplets (MLM) that can be precisely anchored within the pump chamber, thereby eliminating clogging. This design enables the operating frequency to be reduced to 10 Hz and the duty cycle to be increased to 80%, extending the effective actuation duration. Under 12 V square wave signal (12 Vp-p, 6 V DC offset), mEMFP equipped with a single MLM droplet achieves a flow rate of 1.59 × 104 μL min-1, while four serially integrated MLMs deliver 2.20 × 104 μL min-1 with power consumption below 20 mW. What's more, the mEMFP is successfully demonstrated in versatile applications including multifunctional liquid transport, phase-change valving, and personalized thermal management, offering a feasible pathway toward high-performance microfluidic systems.

Thermal interfaces for wearable thermoelectric generators must efficiently transfer heat from the skin while remaining comfortable, yet conventional materials sacrifice breathability for higher thermal conductivity. Here, we develop a breathable thermal interface using electrohydrodynamic printing of liquid metal (LM)-boron nitride (BN)-thermoplastic polyurethane (TPU) composites. The resulting microscale lattice creates localized contact points with the skin, enabling air and moisture transport while maintaining continuous thermal pathways. The composite incorporates thermally conductive, electrically insulating fillers, yielding a through-plane thermal conductivity of 0.37 W·m-1·K-1. When integrated into wearable thermoelectric generators, the printed interface acts as both a compliant thermal interface and a patterned heatsink, supporting heat transfer while preserving skin compatibility. Guided by multiphysics modeling, the device generates a power density of 0.43 μW·cm-2 at thermal equilibrium from an initial temperature difference of 10 °C. The device can be disassembled to recover and reuse both composite constituents and thermoelectric elements without measurable performance loss. This work highlights an interface design approach that prioritizes breathability and skin compatibility in flexible thermoelectric devices, with further improvements in power output and mechanical robustness needed for practical deployment.

The commercialization of liquid lithium-ion batteries has revolutionized the consumer electronics industry. However, conventional lithium-ion batteries with graphite anodes and organic electrolytes are approaching their intrinsic performance limits and struggle to meet the growing demands for higher energy density, reliability, and safety in electric vehicles and large-scale energy storage. Solid-state batteries utilizing lithium or sodium metal anodes are considered promising next-generation energy storage solutions. Despite this potential, the formation of dendrites during charge-discharge cycling remains a critical challenge. Dendrite growth can initiate a destructive feedback loop of crack propagation and further dendrite intrusion, ultimately leading to battery failure and performance degradation. Previous studies have predominantly focused on single physical domains, such as electrochemical, stress, or thermal fields. However, such single-physics approach limits the understanding of dendrite evolution under realistic, coupled multiphysics conditions. This review first compares the morphological characteristics of dendrites in liquid and solid-state metal batteries. It then critically examines the key factors and predictive models of dendrite formation, initially from single-physics and subsequently from an integrated multiphysics perspective. Finally, strategies for mitigating dendrite growth via multiphysics field regulation are summarized. By establishing a comprehensive framework that integrates morphology evolution, multiphysics modeling, and suppression strategies, this work provides a foundational theoretical understanding for addressing dendrite formation in solid-state lithium and sodium metal batteries.

Appropriate color intervention can effectively regulate the autonomic arousal level of children with autism, improve their attention, and mitigate their anxiety. In consideration of the issues associated with traditional intervention methods, including cumbersome procedures and the inability to dynamically track the color-selection behavior of children with autism, this paper presents a fully flexible triboelectric sensor based on liquid metal. This sensor utilizes the current direct writing technology to construct a network-like liquid metal electrode layer, which can maintain excellent electrical conductivity under diverse mechanical deformations and temperature variations. Experiments demonstrated that this triboelectric sensor was capable of effectively detecting subtle variations in touch pressure and exhibited high sensitivity, durability, and structural stability in low-voltage monitoring scenarios. Ultimately, a color preference recognition system incorporating liquid metal flexible sensors was established to conduct color selection detection for children with autism under a light-touch operation without imposing a burden. When combined with machine learning, this system was capable of attaining stable and high-precision color selection recognition, with a recognition rate of 98.125%, offering a low-burden and highly effective technical approach for the individualized color preference assessment of children with autism.

Effective heat conduction has become the most urgent technological challenge in the electronics industry. Currently, alumina (Al2O3) is widely used as a thermal filler in thermal interface materials (TIMs). However, Al2O3-based TIMs generally exhibit relatively low thermal conductivity and high interfacial resistance, which can be attributed to both the low intrinsic thermal conductivity of Al2O3 and the significant Kapitza resistance between filler particles. To address this issue, this study introduces fine-sized aluminum nitride (AlN) fillers into spherical Al2O3 to enhance the thermal conduction network. Additionally, liquid metal can form a "liquid bridge" between filler particles and optimize the interfacial contact, effectively reducing the interfacial thermal resistance between the filler particles. The resulting TIM with a filler loading of 88.3 vol % exhibits an isotropic thermal conductivity of 14.06 W m-1 K-1 and thermal resistance as low as 0.24 K cm2 W-1 under a packaging pressure of 40 psi. Moreover, the composite retains excellent electrical insulation with a volume resistivity of 2.11 × 1013 Ω cm. Due to the wetting effect of the LM, the resulting composite demonstrates excellent plasticity properties, making it well-suited for heat transfer applications in complex or irregular packaging structures. The performance test shows that this TIM outperforms current advanced commercial counterparts, highlighting its significant potential for applications in irregular shape thermal management systems.

Mercury porosimetry is considered the standard method for the characterization of macroporous solids. However, health risks and environmental concerns make a replacement for mercury sought-after. Despite many advances in various techniques, so far, no alternative method is available. Here, we introduce a novel method using, instead of mercury, eGaInSn (Galinstan), a nonhazardous, eutectic gallium alloy, liquid at ambient temperatures, which is already widely used as a replacement for mercury (e.g., thermometers). We utilize a conventional porosimeter with only minor but necessary modifications in sample cell design and filling procedure. To evaluate its potential for pore characterization, we systematically studied the phase and wetting behavior of eGaInSn via intrusion/extrusion experiments in a series of well-defined meso- and macroporous silica (controlled pore glasses), alumina, and disordered carbon materials, including certified reference materials, exhibiting mode pore sizes from the narrow meso- (<20 nm) to the macropore range (1.7 μm). Our results suggest that the intrusion mechanism of eGaInSn represents, analogue to mercury, a confinement-induced shift of the vapor-liquid phase transition of a nonwetting fluid to pressures larger than the saturation vapor pressure. Comparing the pore size/volume distributions obtained by eGaInSn reveals excellent agreement with state-of-the-art mercury porosimetry. Furthermore, we systematically studied the effect of pretreatment conditions of the porous materials, e.g., degassing temperature, on the intrusion/extrusion behavior of eGaInSn and find that the degassing temperature has essentially no influence on the eGaInSn intrusion pressure and curve, but significantly affects the extrusion behavior. We demonstrate that, under certain, well-defined experimental conditions, the intrinsic eGaInSn intrusion-extrusion hysteresis loop is revealed, which contains important additional textural information. In conclusion, our work can be considered the first systematic study of the effect of confinement on the wetting and phase behavior of eGaInSn utilizing intrusion/extrusion measurements with a novel method offering potential to finally replace toxic mercury in the analysis of meso- and macroporous solids.

Elastic conductors are vital for flexible electronics, but the high filler concentrations conventionally required to achieve metallic conductivity severely degrade mechanical properties. Here, we report a poor solvent-induced interfacial self-assembly strategy to fabricate robust elastic conductors. This approach yields a resilient top polymer domain and a bottom liquid metal (LM) polymer interpenetrating conductive domain. Consequently, the conductors achieve exceptional conductivity (3.33×106siemens per meter), extreme stretchability (>1400% strain), and high toughness (>30 megapascals) at a low LM loading (~15% volume proportion). By regulating the self-assembly behavior of LM nanoparticles in elastomers, our method overcomes the traditional trade-off between electrical and mechanical performance. Demonstrating its practical utility, we constructed a wireless stretchable system for monitoring the temperature and motion of living organisms, highlighting its broad applicability in high-performance wearable and implantable electronics.

The intricate cortical folds of large primates physically restrict access to substantial portions of neural information via interface devices. Here, we develop a bioelectronic system, sFlex-Fold, with switchable flexibility, representing the neural interface capable of nondestructive three-dimensional (3D) access to both cortical gyri and sulci, providing large-area, nonpenetrative deep tissue coverage. sFlex-Fold is based on an artificial intelligence (AI)-designed liquid metal alloy (LM-alloy), leveraging the phase change of the tailor-made LM-alloy to create neural interfacing electronics with tunable mechanical response to temperatures ranging from 25° to 37°C. The LM-alloy can be patterned into arbitrary circuit layouts with an ~10-micrometer resolution. The flexibility switching happens at the LM melting point, fine-tuned to 36.2°C, upon in vivo tissue contact, causing a three-order-of-magnitude reduction in the effective modulus of the implanted device. As a result, sFlex-Fold has the unique advantages of both a rigid and flexible state and can be morphed into complex, folded, 3D shapes. This enables nondestructive in vivo implantation into deep cortical sulci while maintaining large coverage (>80 square centimeters) over curved brain surfaces with tissue-matching mechanical compliance. Such 3D structural and mechanical mimicking enables high-quality electrical interfacing as quantitatively assessed using rodent and porcine models.