Search Results (226)

Magnetic photonic crystal microspheres (MPCMs) have emerged as a versatile platform for intelligent sensing and display applications, owing to their integration of magnetic actuation with structural coloration. However, their practical implementation is limited by a fundamental structural constraint: most reported MPCMs adopt anisotropic architectures, resulting in angle-dependent optical responses that require continuous magnetic alignment to maintain uniform coloration. Herein, we propose a different structural paradigm based on non-close-packed, optically isotropic MPCMs. Driven by electrostatic repulsion in solutions, monodisperse Fe₃O₄@tannic acid (TA) core–shell nanoparticles spontaneously assemble into non-close-packed amorphous colloidal arrays, also known as photonic glasses, which are subsequently immobilized within stimuli-responsive polymer networks via emulsification-assisted thermal polymerization. By integrating poly(2-hydroxyethyl methacrylate-co-N-vinylpyrrolidone) (HEMA–NVP) or poly(N-isopropylacrylamide) (PNIPAM) as responsive matrices, the resulting MPCMs exhibit sensitive solvent- or thermo-dependent optical responses. Crucially, structural isotropy ensures angle-independent coloration, eliminating the need for continuous magnetic alignment during optical readout. As evidenced by the unchanged structural color and reflection peak under various magnetic field orientations, this design effectively decouples optical sensing from magnetic actuation. The intrinsic free volume of the non-close-packed architecture allows for isotropic lattice expansion and contraction, leading to broad spectral tunability. Collectively, this work establishes a promising design framework for magnetic photonic microsensors. Full article

This study investigates unsteady magnetohydrodynamic free convection flow past a rotating vertical plate embedded in a Darcy–Forchheimer porous medium. The formulation incorporates Hall current, thermal radiation, viscous dissipation, Joule heating, and an Arrhenius-type chemical reaction with activation energy to represent thermo-reactive transport in an electrically conducting fluid. The coupled nonlinear equations governing momentum, thermal energy, and species concentration are transformed into dimensionless form and solved numerically using the Crank–Nicolson scheme. Grid independence and validation tests confirm the accuracy and stability of the numerical procedure. The results show that electromagnetic forces, rotation, porous resistance, and thermo-reactive effects significantly influence wall shear stress, heat transfer, and mass transport. In particular, the interaction between magnetic field strength and Hall current alters near-wall transport behavior, highlighting the role of electromagnetic coupling in rotating porous systems. The study provides physical insight relevant to the design and analysis of transport processes in high-temperature energy systems, rotating reactors, and porous thermal management devices. Full article

Background/Objectives: Metabolic Dysfunction-Associated Steatotic Liver Disease (MASLD) is a global health crisis, but current diagnostics are limited. Liver biopsy is invasive, magnetic resonance imaging-proton density fat fraction (MRI-PDFF) is expensive, and quantitative ultrasound methods are low-accuracy, especially in patients with a high body mass index (BMI). This study introduces a novel thermo-acoustic (TA) method that generates ultrasound signals based on tissue electrical conductivity, where lean tissue (high in water and electrolytes) absorbs more radio-frequency (RF) energy than fatty tissue, providing a direct molecular contrast for fat. Methods: A prospective, cross-sectional feasibility study compared a new thermo-acoustic fat fraction (TAFF) score with the reference standard MRI-PDFF in 40 subjects with suspected fatty liver disease. Bland–Altman analysis, Deming regression, and Binary classification performance were tested. To establish system stability, a dedicated Repeatability and Reproducibility (R&R) study (N = 14) evaluated inter-operator and intra-operator consistency using an Intraclass Correlation Coefficient (ICC) derived from a two-way random-effects ANOVA model. Results: TAFF estimates demonstrated a substantial correlation (r = 0.89) with MRI-PDFF and an average absolute error of 3.04% fat fraction. Classification performance was high, with an Area Under the Receiver Operating Characteristic Curve (AUROC) of 0.92 at the 12% fat fraction threshold and 0.99 at the 20% fat fraction threshold. The R&R study confirmed robust stability (intraclass correlation = 0.89) and a negligible mean inter-operator difference of 0.36%. Estimation errors showed no statistically significant correlation with BMI or other body habitus measurements. Conclusions: These findings support thermoacoustics’ potential as an accurate, non-invasive, point-of-care solution that can serve as a new imaging biomarker. By providing predictive values closely aligned with MRI-PDFF across the full MASLD spectrum, TAFF can complement currently available ultrasound methods to address the cost and access constraints of MRI for the assessment, diagnosis, and monitoring of MASLD. Full article

Against the backdrop of the ever-expanding practical applications of magnetic nanofluids, the self-driven flow and heat transfer characteristics of water-based Fe₃O₄ magnetic nanofluids were experimentally investigated under a uniform magnetic field in the closed-loop pipeline system in this work. Specifically, Fe₃O₄ nanoparticles were synthesized using the co-precipitation method, and stable magnetic nanofluids with concentrations ranging from 0.025 wt% to 0.150 wt% were prepared using sodium citrate as a dispersant. In the presence of a magnetic field, a closed-loop system that integrates heating and cooling branches was established. Furthermore, the effects of magnetic field strength, temperature difference between the heating and cooling sections, magnetic nanofluid concentration, and pipeline length on the self-circulation flow velocity were discussed, leading to insights into the heat transfer characteristics of the magnetic nanofluid. The results showed that the circulation flow velocity increases with the increase in magnetic field strength, magnetic nanofluid concentration, and temperature difference, while it decreases with the increase in pipeline length. Correspondingly, the heat transfer coefficient between the pipeline wall and the fluid increased significantly with the increase in circulation flow velocity. The priority of factors on the thermomagnetic effect is ranked as magnetic field strength > pipeline length > temperature difference > magnetic nanofluid concentration. Full article

The present study investigated the magnetic hysteresis properties (coercivity and remanent magnetization) of the Zr₂RhTl Heusler alloy using effective field theory (EFT). The study found that the coercive field of Zr₂RhTl reaches a maximum at a specific critical temperature, T_ch, at which the hardness of magnetic materials increases with the coercive field. This behavior is called the “critical hardness temperature (T_ch)”. The hardness of the Zr₂RhTl Heusler alloy increases with temperature until T_ch, reaching a maximum at T_ch. In contrast, it exhibits soft magnetic behavior at T < T_ch and T > T_ch. We suggest that this maximum hardness behavior can enable a new class of thermo-hardness sensors (THSs) and actuators (THAs). Full article

The tendency to design compact systems results in limited space for particular components and heat transfer processes, which influences the removal of heat. Therefore, new methods for heat transfer intensification are being designed. Coupling passive and active methods of heat transfer intensification seems to be a promising approach toward removing high-heat-rate values from a system. The main purpose of the investigation presented was numerical analysis of the influence of nanoparticle materials on the heat transfer processes occurring during thermal convection in the Rayleigh–Benard system configuration under a strong magnetic field environment. The combination of the usage of nanoparticles and a strong magnetic field as one of the options will be justified for its suitability in heat transfer processes. Two types of nanofluids were analysed, namely water-silver and water-copper oxide, with a 0.25 [vol.%] particle concentration, in both cases. The numerical approach considered the nanofluid as the two-phase fluid and was realised in Comsol Multiphysics. Due to the magnetic field, new forces appeared in the system. These forces depend on the magnetic field orientations, and in one orientation, they caused the transfer of higher heat rates by copper oxide nanofluid by 15 [%], while the second one saw the attenuation of natural convection. Silver nanoparticles, because of their weaker magnetic character, intensified heat transfer by approximately 10 [%]. Therefore, copper oxide seems to be a better option for industrial applications. Full article

Over the past 50 years, scientific interest in electromagnetic field-biology interactions has flourished. Important experimental observations and mathematical hypotheses remain central to academic debate. Adey and Blackman found that specific electromagnetic frequencies affect calcium transport in cells. To explain this phenomenon, Liboff introduced ion cyclotron resonance-like (ICR-like) theory, proposing a specific mechanism for ion modulation. Preparata and Del Giudice introduced quantum electrodynamics (QED), offering controversial quantum-level explanations that complement classical models. Lucia and NASA contributed further with thermomagnetic resonance and experimental observations. Together, these hypotheses have partially clarified how weak electromagnetic fields interact with cells and suggest possible parallel endogenous mechanisms. The aim of this narrative review is to provide a clear and logical framework for understanding biological events, both those that arise naturally within biology and those that can be initiated externally through the application of electromagnetic fields. As electromagnetism constitutes one of the four fundamental forces, this interaction warrants rigorous scientific scrutiny. Full article

Magnetic soft manganese–zinc ferrite in a concentration scale ranging from 100 to 500 phr was incorporated into acrylonitrile-butadiene rubber. The work was focused on the investigation of manganese–zinc ferrite content on electromagnetic interference shielding effectiveness and mechanical properties of composites. The rubber-based products used in industrial practice should not only provide good utility and functional properties but should also exhibit good stability towards degradation factors, like oxygen and ozone. Therefore, the samples were exposed to the thermo-oxidative and ozone ageing conditions, and the influence of both factors on the composites’ properties was evaluated. The results demonstrated that the incorporation of ferrite into the rubber matrix resulted in the fabrication of composites with absorption-shielding performance. It was demonstrated that the higher the ferrite content, the lower the absorption-shielding ability. Electrical and thermal conductivity showed an increasing trend with increasing content of ferrite. On the other hand, the study of mechanical properties implied that ferrite acts as a non-reinforcing filler, leading to a decrease in tensile characteristics. Thermo-oxidative ageing tests revealed that ferrite, mainly in high amounts, could accelerate the degradation processes in composites. Though the absorption-shielding performance of composites after ageing corresponded to that of their equivalents before ageing, it can also be concluded that the higher the amount of ferrite in the rubber matrix, the lower the composites’ stability against ozone ageing. Full article

In this study, we present a convenient approach for the preparation of viscose, maghemite, goethite, and poly(methylhydro-dimethyl)siloxane hybrid materials possessing electromagnetic shielding properties, thermal stability, strong magnetization, and very good hydrophobicity. The chemical compositions, morphologies, thermal properties, magnetic measurements, wettability, and dielectric properties of the prepared composites and pristine precursors were thoroughly investigated by Fourier transform infrared spectroscopy (FTIR), scanning and transmission electron microscopy (SEM and TEM), thermal degradation (TG, DTG, and DTA), magnetic measurements (magnetization, thermomagnetic curves, relative magnetic permeability), and dielectric spectrometry. Moreover, the electromagnetic shielding properties of pristine viscose and the final composite were assessed. Full article

Organic Rankine Cycle (ORC) systems with complex configurations exhibit strong thermo-mechanical–electrical–magnetic coupling, making dynamic analysis computationally demanding. This study proposes a multi-time-scale modeling framework that partitions the system into second-, decisecond-, and hybrid-scale subsystems for separate computation, reducing simulation time while maintaining accuracy. Dynamic models are developed for heat exchangers, expanders, pumps, generators, and converters. The method is validated on a basic ORC system using operational data, achieving a mean absolute error of 2.12%, well within the ±5% tolerance. It is then applied to a series dual-loop ORC and a multi-heat-source ORC with series heat exchangers. Results indicate that the dual-loop configuration enhances disturbance rejection to both sink and heat-source fluctuations, while dual-heat-source system dynamics are predominantly governed by the second heat source. The framework enables efficient, accurate simulation of complex ORC architectures and provides a robust basis for advanced control strategy development. Full article

This paper discusses the magnetic properties of Fe-Nb-B-RE (RE = Tb, Tb/Y, Tb/Nd) melt-spun ribbons. Samples were obtained using a typical melt-spinning technique. The dominant amorphous state was confirmed by XRD and thermomagnetic measurements. It was shown that the alloying additions of the RE elements used introduce magnetic anisotropy into amorphous Fe-based structures. This fact was confirmed by magnetic hysteresis loops as well as Kerr microscopy observations. Moreover, increasing Tb content leads to the appearance of a “two-step” reverse magnetization curve. The mean field theory analysis revealed that Tb addition reduces the exchange interaction between the Fe-Fe magnetic moments. The applied thermal treatment caused partial crystallization and the formation of hard magnetic phases with ultra-high coercivity. Full article

Eight diffusion couples were fabricated to systematically investigate the composition-dependent interdiffusion behavior in hcp Dy-Y, Dy-Nd, Sm-Nd, and Sm-Tb binary alloys. The interdiffusion coefficients were determined at two representative temperatures using the Sauer–Freise method based on concentration–distance profiles measured by electron probe microanalysis (EPMA). These experimentally obtained diffusivities, together with available thermodynamic data, were subsequently employed to assess the atomic mobilities of each system by means of the CALTPP (CALculation of Thermo Physical Properties) program within the CALPHAD (CALculation of PHAse Diagrams) framework. The optimized mobility parameters provide a reliable description of the diffusion behavior in all investigated alloys. This reliability is confirmed by the close agreement between the calculated and experimentally measured interdiffusion coefficients, as well as by the strong consistency between the model-predicted and experimental concentration profiles. The present work thus establishes the first set of critically evaluated atomic mobility parameters for these hcp rare-earth binary systems. These results fill an important gap in the kinetic database of rare-earth alloys and lay a robust foundation for future multi-component CALPHAD-based simulations, thereby supporting the design and optimization of advanced rare-earth permanent magnets with improved coercivity and thermal stability. Full article

Coal spontaneous combustion in arid regions poses severe threats to both ecological security and resource sustainability. Focusing on the detection challenges in Fire Zone No. 1 of the Miaoergou Coalfield, Xinjiang, this study proposes an Integrated Geophysical Collaborative Detection Framework that combines high-precision magnetic surveys, spontaneous potential (SP) measurements, and transient electromagnetic (TEM) methods. This innovative framework effectively overcomes the limitations of traditional single-method detection approaches, enabling the precise delineation of fire zone boundaries and the accurate characterization of spatial dynamics of coal fires. The key findings of the study are as follows: (1) High-magnetic anomalies (with a maximum ΔT of 1886.3 nT) exhibit a strong correlation with magnetite-enriched burnt rocks and dense fracture networks (density > 15 fractures/m), with a correlation coefficient (R²) of 0.89; (2) Negative SP anomalies (with a minimum SP of −38.17 mV) can effectively reflect redox interfaces and water-saturated zones (moisture content > 18%), forming a “positive–negative–positive” annular spatial structure where the boundary gradient exceeds 3 mV/m; (3) TEM measurements identify high-resistivity anomalies (resistivity ρ = 260–320 Ω·m), which correspond to non-waterlogged goaf collapse areas. Spatial integration analysis of the three sets of geophysical data shows an anomaly overlap rate of over 85%, and this result is further validated by borehole data with an error margin of less than 10%. This study demonstrates that multi-parameter geophysical coupling can effectively characterize the thermo-hydro-chemical processes associated with coal fires, thereby providing critical technical support for the accurate identification of fire boundaries and the implementation of disaster mitigation measures in arid regions. Full article

Acrylonitrile–butadiene–styrene (ABS) has been widely used as an engineering thermoplastic, and the increasing post-consumer waste of ABS plastics calls for efficient and sustainable recycling technologies. The recent advances in ABS recycling technologies were investigated to enhance material recovery, purity, and environmental performance. Thermo-oxidative degradation compromises mechanical integrity during reprocessing, while minor reductions in molecular weight increase melt flow rates. Surface modification techniques such as boiling treatment, Fenton reaction, and microwave-assisted flotation facilitate the selective separation of ABS from mixed plastic waste by enhancing its hydrophilicity. Dissolution-based recycling using solvent and anti-solvent systems enables the recovery of high-purity ABS, though some additive losses may occur during subsequent molding. Magnetic levitation and triboelectrostatic separation provide innovative density and charge-based sorting mechanisms for multi-plastic mixtures. Thermochemical routes, including supercritical water gasification and pyrolysis, generate fuel-grade gases and oils from ABS blends. Mechanical recycling remains industrially viable when recycled ABS is blended with virgin resin, whereas plasma-assisted mechanochemistry has emerged as a promising technique to restore mechanical properties. These recycling technologies contribute to a circular plastic economy by improving efficiency, reducing environmental burden, and enabling the reuse of high-performance ABS materials. Full article

Thermo-mechanical fatigue remains one of the more difficult phenomena to analyze due to the interplay between temperature, mechanical properties, and microstructural features of the material. For austenitic stainless steel, thermo-mechanical fatigue plays a particularly critical role—temperature changes the affinity of $\gamma$ austenite to transform into ${\alpha }^{\prime }$ martensite under overcritical deformation. This paper presents the results of an in situ study of $\gamma \to {\alpha }^{\prime }$ deformation-induced transformation kinetics at elevated temperatures in AISI 347. Fatigue tests were conducted in the temperature range of 20 to 320 °C. A uniaxial magnetic balance was used to directly measure the change in ferromagnetic volume fraction of the fatigue specimens as the fatigue load was applied. From this data, an empirical mathematical model was found. This model describes the kinetics of $\gamma \to {\alpha }^{\prime }$ transformation as an exponential function of temperature, where the rate of phase transformation decreases with temperature, asymptotically approaching zero but never actually reaching it. Full article