Microscopic modeling of thermal coupling in composite refractory masonry ladle with different joint configurations

Bayesian-optimized deep neural network surrogate for orientation-driven anisotropic thermal conductivity prediction in hybrid polymer nanocomposites

ConspectusLanthanide-doped upconverting nanoparticles (UCNPs) convert near-infrared (NIR) light into visible emission through multiphoton absorption processes. This property has made them useful tools for sensing and single-particle studies in biological environments. Their characteristic narrow emission lines, resistance to photobleaching, and the thermal coupling between the excited states of trivalent erbium (Er3+) have positioned UCNPs as a practical platform for intracellular thermometry despite their moderate sensitivity. Their response can be measured with standard microscopes using inexpensive NIR excitation sources, enabling experiments that are not easily achieved with other types of nanoscale thermometers. However, using UCNPs inside living cells also reveals important limitations because the intracellular medium is chemically complex and may alter the emission properties that form the basis of the thermal readout. Variations in local pH, ion concentration, viscosity, or molecular crowding can shift energy levels or modify nonradiative relaxation pathways. As a result, establishing the reliability of UCNP thermometry inside cells requires dedicated studies on particle stability, surface chemistry, and the influence of the cytoplasmic environment. Understanding these effects is essential for determining whether ratiometric UCNP thermometry can serve as a quantitative intracellular tool rather than only a qualitative indicator of heating. UCNPs have also enabled new single-particle experiments through optical trapping. A tightly focused NIR beam can immobilize an individual nanoparticle while simultaneously exciting its upconversion emission, allowing continuous monitoring of spectral changes, rotational dynamics, and local mechanical properties. These studies provide access to information that is hidden in ensemble measurements, such as particle-particle radiative interactions or the coupling between particle rotation/movement and local viscosity. Yet optical trapping also brings its own challenges: the forces acting on sub-100 nm UCNPs are modest, and trapping stability is strongly affected by laser-induced heating. Increasing dopant concentration improves confinement but raises thermal load, leading to a trade-off that must be carefully balanced. Approaches based on plasmonic enhancement are not suitable due to their additional heating, motivating interest in alternative photonic structures such as dielectric metasurfaces that could strengthen confinement while keeping temperatures low. Together, intracellular thermometry and single-particle trapping illustrate both the strengths and the current limitations of UCNPs. Their optical properties make them accessible probes for measuring local temperature and mechanical responses, but their performance heavily depends on the surrounding environment. In this Account, we summarize our efforts to understand UCNP behavior under realistic biological and trapping conditions. We discuss the stability of the thermometric response inside cells, the confinement-heating balance in optical traps, and the opportunities offered by single-particle measurements for studying light-matter interactions at the nanoscale. These considerations outline a path toward more reliable sensing and manipulation strategies based on UCNPs.

BaFBr:Eu2+/3+ monodisperse nanocrystals were synthesized via solution-phase thermolysis of metal bromodifluoroacetates. Their luminescence response was characterized between 80 and 430 K. Nanocrystals exhibited square-plate shape with approximate dimensions 33 nm × 5 nm and polydispersities below 8% in both dimensions. The emission spectrum of BaFBr:Eu2+/3+ featured a broad band in the near UV arising from fd-f transitions of Eu2+ as well as a series of line-like bands from f-f transitions of Eu3+. No line emission from the 4f7 (6P7/2) level of Eu2+ was observed. The structure and dynamics of the excited states involved in Eu2+ violet emission were established from the temperature dependence of their time-resolved decays. The lifetime of the 4f65d1 excited-state manifold exhibited antithermal quenching between 80 and 430 K. This observation could not be rationalized invoking thermalization of the lowest level of the 4f65d1 manifold to the higher-lying 4f7 (6P7/2) level. A satisfactory explanation was achieved considering thermal coupling between the lowest level of the 4f65d1 manifold and a higher-lying 4f65d1 level. The latter featured a smaller radiative rate than the former (≈105vs. 106 s-1) and the gap between these two levels was estimated to be ≈500 cm-1. The 4f7 (6P7/2) level was located ≈100 cm-1 above the higher-lying 4f65d1 level and, unlike the case of BaFCl, did not need to be invoked at all to rationalize the temperature dependence of Eu2+ emission.

Thermal activation of reactants is a key initial step in catalysis, which can occur either by temperature-driven activation of surface adsorbates or by radiation-driven excitation above the surface. Here, two configurations of five-bilayer Ni/SiO2 thermal metasurfaces are engineered to provide superblackbody near-field emission within the CO2 asymmetric stretching band of 4.3 μm wavelength, with broadband and narrowband absorption, respectively. Thermal dipole simulations show that the broadly absorbing cylindrical array drives edge-guided resonances with a near-uniform rim field, whereas the narrowly emitting cuboid array with higher absorptivity shows corner field localization due to higher field interior confinement. Both metasurfaces have high near-field intensities in excess of blackbody radiation by up to ×2. Experimentally, the wideband metasurface achieves a higher CO production rate and >50% higher CO/CH4 selectivity. In situ-diffused reflectance Fourier transform spectroscopy indicates reduced buildup of carbonate intermediates and adsorbed CO on the wideband metasurface relative to the narrowband metasurface, indicating faster CO desorption and suppressed methanation. Density functional theory simulations support the observation by showing that gas CO2 bond stretching can eliminate the kinetic energy barrier to CO2 chemisorption and promote CO2 dissociation toward CO formation. Minimizing CO adsorbate stretching suppresses hydrogenation pathways that proceed through formate intermediate and subsequent methanation. Overall, the engineering of the metasurface thermal dipole-induced field coupling with confinement or radiative channels, modulated by emission spatial distribution, can independently activate reactant molecules above the surface while favoring the surface for desorption of products. This shows a physically driven approach to catalysis by decoupling the surface activation and desorption counteractions.

In this work, a 2D axisymmetric FEM model was produced to simulate OpenStar Technologies' Junior Core Magnet. The model was created in COMSOL Multiphysics, with electromagnetic and thermal coupling. This model was used to simulate the Core Magnet under full-field conditions, and was verified against the specifications of the Core Magnet. Producing the model involved creating lookup tables of homogenised electrical and thermal properties for each of the 14 solder impregnated coils, applying coordinate transformations to these lookup tables, and creating 2D axisymmetric equivalent geometry of the complex copper interface buses and plates between the coils. This paper provides insight into understanding the behaviour of NI coils and how they influence quench dynamics, current redistribution, and thermal response. The modelling approach demonstrates that computationally efficient simulations can be achieved through homogenisation and geometry simplification, offering a valuable tool for the design, optimisation, and safety assessment of large-scale superconducting magnets.

Threshold of thermoconvective flows in a liquid metal battery with thermal coupling with its environment

Exergy-informed collaborative control of refrigerant-based integrated thermal management systems for electric vehicles

AI-integrated multifunctional phase change e-skin: synergizing thermal management with multimodal sensing

To address the difficulty of detecting demagnetization severity in permanent magnet synchronous motors (PMSMs), this paper proposes a demagnetization severity detection method based on temperature signal and Convolutional Neural Network (CNN). First, the differences between local demagnetization and eccentricity fault in stator current harmonics are analyzed from an electromagnetic perspective, and fast Fourier transform (FFT) is used for frequency-domain analysis of the stator current to identify local demagnetization faults. On this basis, an electromagnetic–thermal coupling model is established by considering motor losses and heat dissipation boundary conditions to obtain the winding temperatures under different demagnetization severities and operating conditions. Furthermore, the temperature time series, together with speed and load torque, is constructed into a three-dimensional state space, and the proposed Conditionally Modulated Multi-Scale Convolutional Neural Network (CMSCNN) is introduced for feature learning to achieve demagnetization severity detection. Experimental results show that the proposed method achieves an average detection accuracy of 98.06% on the simulation test set and outperforms the baseline CNN model. On measured data collected from the faulty prototype, the average detection accuracy reaches 93.34%, verifying the effectiveness of the proposed method for demagnetization severity detection.

Fuel vapor can be ignited by lightning through various means, particularly through hot spot formation on fuel tank skins. The wing fuel tank cover and its surrounding outer plates together form part of the aerodynamic shape of an aircraft. The lightning protection design of the fuel system, including wing fuel tank, is of great significance for ensuring the aircraft safety. Based on the Joule heating and implosion effect, the damage response of a composite fuel tank cover subjected to lightning strikes is analyzed in this paper. The adopted method combines electrical–thermal coupling with explicit dynamics analysis. Firstly, a finite element model of the fuel tank cover is established using electrical–thermal coupling elements, and the lightning current impact simulation is carried out under given electrical boundary conditions and thermal boundary conditions. On one hand, the ablation criterion is determined by the Joule heating effect and the sublimation temperature of materials. The thermal damage of composite materials subjected to transient high currents is obtained through transient thermal analysis. On the other hand, special implosion elements are selected according to the temperature distribution obtained from the electrical–thermal coupling analysis. The original composite material model in the implosion region needs to be replaced with a new material model described by the high-explosive material model and the JWL equation of state. The von Mises stress distribution and pressure distribution on the structure after implosion are discussed in detail. The results show that concave pits are formed near the implosion zone. Unlike the thermal damage morphology defined by the ablation criterion, the implosion effect makes the damage distribution deviate from the initial fiber direction of each layer. The implosion dynamic method reveals the internal damage and pit and bulge phenomenon around the lightning attachment area to a certain extent.

The race toward performance increase and computing power has led to chips with heterogeneous and complex designs, integrating an ever-growing number of cores on the same monolithic chip or chiplet silicon die. Higher integration density, compounded with the slowdown of technology-driven power reduction, implies that power and thermal management become increasingly relevant. Unfortunately, existing research lacks a detailed analysis and modeling of thermal, power, and electrical coupling effects and how they have to be jointly considered to perform dynamic control of complex and heterogeneous Multi-Processor System on Chips (MPSoCs). To close the gap, in this work, we first provide a detailed thermal and power model targeting a modern High Performance Computing (HPC) MPSoC. We consider real-world coupling effects such as actuators’ non-idealities and the exponential relation between the dissipated power, the temperature state, and the voltage level in a single processing element. We analyze how these factors affect the control algorithm behavior and the type of challenges that they pose. Based on the analysis, we propose a thermal capping strategy inspired by Fuzzy control theory to replace the state-of-the-art PID controller, as well as a root-finding iterative method to optimally choose the shared voltage value among cores grouped in the same voltage domain. We evaluate the proposed controller with model-in-the-loop and hardware-in-the-loop co-simulations. We show an improvement over state-of-the-art methods of up to \(5\times\) the maximum exceeded temperature while providing an average of \(3.56\%\) faster application execution runtime across all the evaluation scenarios.

In this paper, we developed a opto-electro-thermal model using the 3D finite element method (FEM) in order to assess the temperature-dependent performance of perovskite solar cells (PSCs). The FEM-based model we developed is fully coupled, allowing us to model the optical absorption, charge transport, and heat generation processes all at once, which will provide a more precise evaluation of device performance. Four perovskite absorber materials (MASnI[Formula: see text], MAPbI[Formula: see text], CsPbI[Formula: see text], and CsSnI[Formula: see text]) were evaluated based on three heat generation mechanisms: Joule heating, non-radiative recombination, and thermalization. Based on the proposed model, the extent of temperature rise within the device and its impact on device performance-primarily open-circuit voltage ([Formula: see text]) and power conversion efficiency (PCE) are assessed. The simulation results show that the temperature-dependent performance of the PSC, varies according to the absorption layer material, as each type of absorber showed unique thermal behavior. In particular, CsSnI[Formula: see text] exhibited notable temperature-dependent performance under thermal coupling, with a [Formula: see text] reduction of only 2.38% and a PCE variation of 9.12%, showing a high photovoltaic response but higher temperature sensitivity under temperature variation compared to CsPbI[Formula: see text].

Reliable in situ temperature monitoring is essential for the safe operation of liquid-nitrogen-cooled superconducting cables, yet conventional electrical sensors are often difficult to scale to multi-point deployment in cryogenic, high-current environments. This work presents a fiber Bragg grating (FBG) sensing solution for in situ temperature monitoring of superconducting cables in liquid nitrogen. An FBG array packaged with a polyimide-coated fiber inside a 3 mm stainless-steel tube is deployed along the cable centerline to provide multi-point temperature measurements of the cable core. The system is validated under liquid-nitrogen immersion with a 2000 A current turn-on/turn-off test, with a 1 Hz update rate and a steady-state temperature fluctuation within ±0.1 °C. Experimental results show a continuous temperature decrease during liquid-nitrogen cooling, followed by a cryogenic plateau, during which a spatially consistent 0.6–0.7 °C current-induced temperature rise is observed across multiple sensing points in the present 2000 A turn-on/turn-off test, followed by recovery after current shutoff. Small-amplitude fluctuations during the plateau are attributed to packaging-dependent thermal coupling between the centerline-deployed sensor and the cable core. These results indicate that the proposed FBG-based approach enables reliable cryogenic thermometry for superconducting cables in liquid nitrogen and provides a practical tool for in situ operational condition assessment.

ABSTRACT Electrically Controlled Solid Propulsion (ECSP) is a revolutionary method of propulsion, which combines the solid propellant high energy density with real time controllability made possible by electrical current. ECSP is a sharp contrast to the traditional solid propellants whose thrust profiles were fixed, with on‐demand ignition, extinguishment, and fine modulation of the thrust. New developments have seen optimized electrochemical salt systems, nanostructured additives and advanced electrode materials, all of which have enhanced ignition reliability, control of burning rate and combustion efficiency. Additionally, multi‐stage decomposition studies and ion transport studies have further broadened the knowledge of the electro thermal coupling mechanisms. They find use in micro‐propulsion units to serve from satellite missions to rocket motors, where programmability increases the safety, flexibility in the missions, and operational requirements. Nonetheless, there are still some problems with ignition delays, long‐term stability, electrode degeneration, and scaling to increased application. The state‐of‐the‐art in ECSP, including technical innovations, outstanding shortcomings, and future direction to a practical implementation in aerospace and defense propulsion are critically examined in this review.

ABSTRACT This study investigates thermo fluid coupling mechanisms governing temperature distribution and thermal stress evolution in Solid Oxide Electrolyzer Cells (SOEC) under varying operating conditions. A multiphysics model integrating electrochemistry, gas flow and diffusion, heat transfer, and thermo mechanical response is developed to examine the effects of operating temperature, steam ratio, air flow rate, and flow configuration on electrolysis performance, internal temperature fields, and stress distributions. The numerical model is validated against the experimental data of Tu et al., showing a maximum polarization curve deviation of 9.84%. Results show that increasing operating temperature from 973 K to 1073 K raises current density by approximately 31.7%, while increasing peak temperature by about 11.5% and electrolyte tensile stress from 439.9 MPa to 518.6 MPa. Increasing the cathode side steam fraction from 60% to 90% improves current density by about 11.7%, with minor increases in peak temperature below 1% and stress near 1%. Increasing the anode side air flow rate from 10 sccm to 50 sccm reduces temperature spread and decreases maximum electrolyte tensile stress by approximately 7%. These results highlight the role of thermo fluid interactions in temperature gradient development and thermal stress evolution in SOECs.

Failure probability model for LPG spherical tanks under multi-pool fire coupling

This study proposes a novel sector-coupled energy system integrating an innovative small modular reactor (i-SMR), an open-air Brayton cycle (OABC), and a direct air capture (DAC) unit. The system leverages thermal and flow coupling, using regeneration heat and intake air for CO₂ capture. A dynamic adsorption model based on Golden’s string rule and thermodynamic analysis under off-design conditions quantified power loss, CO₂ purity, and capture over full cycles. Parametric optimization identified optimal performance at a mass flow of 332 kg/s and adsorption time of 7 h, minimizing capture cost while maintaining high CO₂ purity and near-saturation recovery. Under these conditions, net power loss was limited to 1.7–2.5 MWe relative to a DAC-free baseline, with total capture energy consumption below 1.4 GJ/tCO₂. These results provide the first theoretical demonstration of an i-SMR integrated OABC–DAC system, showing its potential to achieve efficient, low-penalty carbon capture through system-wide heat and flow synergies. • Small Modular Reactor based Direct Air Capture integration method proposed to reduce energy consumption. • Thermodynamic analysis is conducted to estimate energy penalty for Small Modular Reactor - Open Air Brayton Cycle – Direct Air Capture system. • Quasi-steady state modeling conducted for Direct Air Capture with integrated i-SMR.

Damage constitutive model and corrosion kinetics investigation of cement paste under thermal mechanical chemical coupling conditions

Nonuniform temperatures in lithium-ion battery modules, caused by manufacturing inconsistencies, vibrations, and unequal line resistances, lead to uneven current distribution and accelerated degradation of the battery. Existing thermal management methods face challenges in achieving real-time cell-level balancing due to limited intercell modeling, high computational cost, and lack of closed-loop control. This article proposes a model predictive temperature balancing control (MPTBC) strategy based on a scalable 2-D thermal network model (TNM) that captures intercell thermal coupling and enables real-time prediction with reduced computational cost. A physics-informed neural network (PINN) models the nonlinear internal resistance, with Bayesian optimization (BO) used to efficiently identify optimal parameters. The MPTBC is implemented on a four-module, high-power-density, single-input multioutput (SIMO) switched-capacitor (SC) converter. Experiments validate the TNM accuracy and demonstrate that MPTBC effectively minimizes cell-to-cell temperature differences.