Search Results (1,628)

In hybrid active–passive magnetic shielding systems, active compensation coils are used to suppress residual magnetic fields inside the shield. However, due to the intrinsic hysteresis of high-permeability materials, the compensation fields inevitably magnetize the passive layers. This process introduces new and unpredictable remanent magnetization, paradoxically worsening the remanence stability during active compensation. This study systematically investigates and quantifies how the number of passive shielding layers affects remanence instability. A combined approach of theoretical analysis, finite-element simulations, and experimental validation is employed. The results reveal a key counter-intuitive finding: although adding more shielding layers enhances the static attenuation of external fields, it markedly amplifies the remanence instability induced by active compensation. Specifically, multi-layer shields exhibit larger remanence changes under identical compensation-field excitations. This finding reveals a previously overlooked performance trade-off and provides new design insights for ultra-high-precision shielding systems. These findings provide essential guidance for optimizing the design and operation of next-generation ultra-high-precision magnetic shielding devices and their applications in frontier areas such as fundamental physics and biomedicine. Full article

This study aims to identify optimal parameters for the clinical implementation of magnetic fields in therapeutic contexts, with a particular focus on in vitro magneto-mechanical actuation in biological systems. This approach relies on the transduction of magnetic energy into mechanical stress at low frequencies (<<100 Hz). Accordingly, the investigation centers on evaluating the magnetic field gradients responsible for initiating the motion of intracellular magnetic nanoparticles and the resulting mechanical forces acting upon them. To achieve this, a novel, custom-built, and highly adaptable three-dimensional turntable system was designed, calibrated, and implemented. This apparatus allows the generation of magnetic fields with precisely tunable amplitude and frequency, enabling controlled activation of magneto-mechanical mechanisms. In vitro experiments using this device facilitated the exposure of cancer cells to well-characterized magnetic fields, thereby inducing mechanical stimulation in the presence of nanoparticles distributed within intracellular or extracellular environments. Quantitative measurements of magnetic field intensities were performed, providing estimations of the forces exerted by magnetic nanoparticles with diverse physical characteristics (phase, size, and shape) under varying magnetic field gradients. Full article

During the operation of the magnetic fluid sealing device, a large amount of heat is generated due to the viscous friction of the magnetic fluid, causing the shaft to deform and thus affecting the sealing effect. This paper explores the thermal expansion effect of the magnetohydrodynamic sealing device under the working conditions of an axle diameter of 1030 mm and a maximum rotational speed of 700 r/min. The temperature distribution law under the action of a magnetic field, the influence of thermal deformation caused by temperature on the sealing performance, and the influence of the selection of shaft and pole shoe materials on the magnetic fluid sealing device were studied. Research findings show that in magnetic fluid sealing, an increase in system temperature can enhance the sealing effect, but it will cause thermal expansion of the rotating shaft and change the gap. By adopting a combination of different materials for the rotating shaft and the pole shoe, the sealing performance can be optimized and improved. Full article

Organ fibrosis is a progressive and often irreversible pathological process characterized by excessive deposition of extracellular matrix, leading to tissue dysfunction and failure. Despite its significant impact on various organ systems, available antifibrotic therapies remain limited. This review focuses on novel therapeutic approaches to inhibit fibrosis and improve clinical outcomes. Current strategies include small molecule inhibitors, monoclonal antibodies targeting fibrosis mediators, gene therapies, and cell-based approaches, including mesenchymal stem cells and induced pluripotent stem cells. In addition, the development of innovative drug delivery systems and combination therapies involving pulsed magnetic fields (PMFs) opens new possibilities for increasing the precision and efficacy of treatment. In recent years, multiomic approaches have enabled a better understanding of fibrosis mechanisms, facilitating the personalization of therapy. The role of artificial intelligence in drug discovery has also increased, as exemplified by models that support the design of small-molecule inhibitors currently undergoing clinical evaluation. This review discusses key signaling pathways involved in fibrosis progression, such as TGF-β, p38 MAPK, and fibroblast activation, as well as novel therapeutic targets. Although clinical trial results indicate promising potential for new therapies, challenges remain in optimizing drug delivery, considering patient heterogeneity, and ensuring long-term safety. The future of fibrosis therapy relies on integrating precision medicine, combination therapies, and molecularly targeted strategies to inhibit or even reverse the fibrosis process. Further intensive interdisciplinary collaboration is required to successfully implement these innovative solutions in clinical practice. Full article

The possibility of determining the phase and current errors of an existing or newly designed current instrument transformer on the basis of special characteristics of the core material is examined. One of the characteristics represents the dependence between the magnetic field intensity on the core sheet surface, measured at the instant when induction is at its peak, and the mean peak induction in the cross section of the sheet. The other characteristic represents the dependence between the field intensity value measured at the instant when induction passes through zero and the peak induction value. The characteristics must be determined for the sinusoidal shape of the induction curve. The secondary winding of the current instrument transformer should be uniformly distributed along the core. One must know the following: the number of turns in the primary and secondary winding, respectively, the resistance of the secondary winding and the resistance at the secondary winding output when the primary current is being converted. Indicated relations provide a clear formula for designing effective current transformers. The main contribution of this paper is to present the method for estimating the parameters of current transformer a priori, relying on characteristics of the core material. However, this formula combined with elements of artificial intelligence—nature-inspired optimization algorithms—results in a convenient tool for optimal core geometry design. The paper presents an extension of the method to a smart design approach with application of the Birch-inspired Optimization Algorithm (BiOA). Full article

Microfluidics is considered a revolutionary interdisciplinary technology with substantial interest in various biomedical applications. Many non-Newtonian fluids often used in microfluidics systems are notably influenced by the external active fields, such as acoustic, electric, and magnetic fields, leading to changes in rheological behavior. In this study, a numerical investigation is carried out to explore the rheological behavior of non-Newtonian fluids in a T-shaped microfluidics channel integrated with complex micropillar structures under the influence of acoustic, electric, and magnetic fields. For this purpose, COMSOL Multiphysics with laminar flow, pressure acoustic, electric current, and magnetic field physics is used to examine rheological characteristics of non-Newtonian fluids. Three polymer solutions, such as 2000 ppm xanthan gum (XG), 1000 ppm polyethylene oxide (PEO), and 1500 ppm polyacrylamide (PAM), are used as a non-Newtonian fluids with the Carreau–Yasuda fluid model to characterize the shear-thinning behavior. Moreover, numerical simulations are carried out with different input parameters, such as Reynolds numbers (0.1, 1, 10, and 50), acoustic pressure (5 Mpa, 6.5 Mpa, and 8 Mpa), electric voltage (200 V, 250 V, and 300 V), and magnetic flux (0.5 T, 0.7 T, and 0.9 T). The findings reveal that the incorporation of active fields and micropillar structures noticeably impacts fluid rheology. The acoustic field induces higher shear-thinning behavior, decreasing dynamic viscosity from 0.51 Pa·s to 0.34 Pa·s. Similarly, the electric field induces higher shear rates, reducing dynamic viscosities from 0.63 Pa·s to 0.42 Pa·s, while the magnetic field drops the dynamic viscosity from 0.44 Pa·s to 0.29 Pa·s. Additionally, as the Reynolds number increases, the shear rate also rises in the case of electric and magnetic fields, leading to more chaotic flow, while the acoustic field advances more smooth flow patterns and uniform fluid motion within the microchannel. Moreover, a proposed experimental framework is designed to study non-Newtonian fluid mixing in a T-shaped microfluidics channel under external active fields. Initially, the microchannel was fabricated using a high-resolution SLA printer with clear photopolymer resin material. Post-processing involved analyzing particle distribution, mixing quality, fluid rheology, and particle aggregation. Overall, the findings emphasize the significance of considering the fluid rheology in designing and optimizing microfluidics systems under active fields, especially when dealing with complex fluids with non-Newtonian characteristics. Full article

High-nitrogen organic chemical wastewater is characterized by high chemical oxygen demand (COD_Cr), poor biodegradability, and toxic nitrogenous organics, posing significant challenges for conventional biological treatment. In this study, a dual-electrical treatment strategy integrating an electromagnetic Fenton (EM-Fenton) pretreatment unit with a three-dimensional biofilm electrode reactor (3D-BER) is proposed. The EM-Fenton system used iron–carbon fillers under electric and magnetic fields to generate hydroxyl radicals (·OH), enabling efficient oxidation of nitro-aromatic compounds and the conversion of organic nitrogen into NO₃⁻-N, while reducing Fe²⁺ input and iron sludge generation. Subsequently, the 3D-BER, filled with Fe₃O₄/Mn₃O₄-modified polyurethane spheres, facilitated autotrophic denitrification and phosphorus removal through enhanced extracellular electron transfer and trace hydrogen (H₂) release. Experimental results demonstrated that the EM-Fenton system achieved COD_Cr and NH₄⁺ removal rates of over 40% and 14%, respectively, under optimal HRT. The 3D-BER further improved removal efficiencies, with TN and TP reductions exceeding 80% and 81%, respectively, significantly outperforming the control groups. Microbial analysis revealed the enrichment of functional genera, such as Pararhodobacter and Thauera, and the upregulation of key denitrification pathways. This coupled system demonstrated high treatment efficiency, process synergy, and microbial selectivity, offering a promising approach for the advanced treatment of high-nitrogen industrial wastewater. Full article

An automatic optimization approach to the non-periodic (NP) folded-waveguide slow-wave structure (FW-SWS) is proposed for the high efficiency traveling wave tube (TWT). Considering the beam-wave synchronism condition, the data of the beam velocity distribution are analyzed and utilized for automatic optimization. For concise expression, a W-band concentric arc NP FW-SWS TWT is automatically optimized as an example, where the beam voltage is set as 6000 V, the beam current is 0.12 A, the magnet field is 0.5 T, and the input power is 0.4 W. Without any training data or previous given datasets, the output power (electronic efficiency) can be optimized to reach 238.7 W (33.1%) at 94 GHz by the automatic optimization approach code within 22.7 h. Full article

The stability of deep marine shale wellbores is influenced by both bedding anisotropy and drilling fluid intrusion. Existing models fail to adequately account for the coupled effects of intrusion depth and strength degradation. This study, targeting Longmaxi Formation shale, established a collapse pressure prediction model incorporating drilling fluid intrusion depth through direct shear tests and nuclear magnetic resonance (NMR) techniques. Experimental results indicate that shear strength reaches its minimum at β = 45°, decreasing by approximately 60% compared to β = 0° or 90°. Intrusion causes exponential decay in bedding plane strength, with the cohesion degradation coefficient λ_c = 0.158 mm⁻¹ significantly exceeding the internal friction angle degradation coefficient λ_φ = 0.089 mm⁻¹. Sensitivity analysis indicates that bedding angle and invasion depth rank third (±3%) and fourth (±1.5%), respectively, in influencing collapse pressure. Field validation confirmed excellent model prediction accuracy (R² = 0.956; RMSE = 0.55 MPa; MAPE = 1.05%), with all errors below 4%. This model accurately predicts the time-varying characteristics of collapse pressure, providing a theoretical basis for optimizing the design of drilling fluid density. Full article

The dynamic model and nonlinear forced vibration of a laminated beam with magnetostrictive layers, embedded on a nonlinear elastic Winkler–Pasternak foundation, in the presence of an electromagnetic actuator, mechanical impact, dry friction, a longitudinal magnetic field, and van der Waals force is investigated in the present work. The dynamic equations of this complex system are established based on von Karman theory and Hamilton’s principle. Then, by means of the Galerkin–Bubnov procedure, the partial differential equations are transformed into ordinary differential equations. The Optimal Auxiliary Functions Method (OAFM) is applied to solve the nonlinear differential equation. The results obtained are validated by comparisons with numerical results given by the Runge–Kutta procedure. Local stability in the neighborhood of the primary resonance is examined by means of the homotopy perturbation method, the Jacobian matrix, and the Routh–Hurwitz criteria. Global stability is studied by introducing the control law input function and using the approximate solution obtained by the OAFM in the construction of the Lyapunov function. La Salle’s invariance principle and Potryagin’s principle complete our study. The effects of some parameters are graphically presented. Our paper reveals the immense potential of the OAFM in the study of complex nonlinear dynamical systems. Full article

Optimizing the shut-in and flowback processes is crucial for improving oil recovery and mitigating formation damage in shale oil development. However, the mechanisms governing fracturing fluid migration and its impact on permeability, particularly across different lithologies, remain poorly understood. This study investigates the spontaneous imbibition behavior of fracturing fluid and the resulting permeability damage in two predominant lithotypes (dolomitic siltstone and argillaceous siltstone) from the Jimsar shale oil reservoir. By integrating low-field nuclear magnetic resonance (NMR) monitoring with core flooding experiments, we dynamically characterize fluid migration and quantitatively evaluate damage rates. The results reveal that lithology exerts a fundamental control on these processes. Dolomitic siltstone, with its higher brittle mineral content and well-connected pore network, facilitates deeper fracturing fluid invasion (30.47 mm) and more efficient oil displacement. In contrast, argillaceous siltstone, which is rich in clay minerals, exhibits stronger capillary trapping and suffers more severe permeability damage (~70%) compared to dolomitic siltstone (~46%), primarily due to the synergistic effects of water blocking and clay swelling. Furthermore, the impact of shut-in time on permeability damage follows a non-monotonic trend, reflecting a dynamic competition between imbibition-driven oil recovery and fluid-induced damage. Flowback analysis on core plugs reveals an economic critical point, beyond which further permeability recovery becomes marginal. This core-scale finding underscores the importance of the initial flowback stage for efficient cleanup and provides a scientific basis for optimizing flowback strategies in the Jimsar shale and similar unconventional reservoirs. These findings offer guidance for designing lithology-specific fracturing fluid systems, optimizing shut-in durations, and tailoring flowback strategies in the Jimsar shale and analogous unconventional reservoirs. Full article

Presented here is a 2-D analytical model for predicting the magnetic field distribution in a surface-mounted permanent magnet (SPM) rotor with multi-layered segmented permanent magnets (PMs). Each layer is treated independently, enabling the linear superposition of magnetic fields across all layers. The model employs subdomain modeling combined with the separation of variables, with the magnetic vector potential expressed as a Fourier series to derive the airgap magnetic field. The formulation is generalizable to five regions in each layer: outer airgap, optional outer inactive magnetic layer, active magnetic layer(s), optional inner inactive magnetic layer, and inner airgap. Validation against finite element analysis (FEA) shows a prediction difference of around 0.5% in airgap flux density. The model’s design utility is demonstrated through a genetic algorithm (GA) optimization, which maximizes static flux linkage and confirms performance improvements from the multi-layered configuration. Full article

This paper proposes an integrated sensor for voltage and current distribution network insulators, based on electric field coupling and TMR magnetic sensing, to address the issues of traditional voltage and current separation measurement, insulator safety after primary and secondary fusion, uncertainty in voltage measurement gain, and interference resistance in TMR current measurements. Through simulation and optimization, the design of the embedded voltage-sensing unit in the insulator is achieved, ensuring uniform electric field distribution, determining the transfer function, and minimizing partial discharge, thereby ensuring insulator safety and improving voltage measurement accuracy. Additionally, a self-integrating circuit design is used to widen the low-frequency dynamic range and increase the voltage division ratio. Moreover, an open-type two-stage magnetic ring current sensor based on TMR is proposed, with optimized magnetic ring dimensions to detect currents from low to medium ranges, addressing eccentricity errors and improving sensitivity, immunity to interference, and magnetic field uniformity. The experimental results show that this integrated sensor can effectively ensure measurement accuracy, stability, and dynamic range. Full article

Amidst the urgent demand for sustainable alternatives to petrochemical plastics, this work incorporated oregano essential oil Pickering emulsion (AOPE; stabilizer: acetylated chitin nanocrystals (a-ChNCs)) into the gelatin matrix. Through precisely engineered hydrogen-bonding networks at the a-ChNCs/gelatin interface, achieved through the systematic optimization of AOPE concentration, a high-performance bio-based gelatin composite film (designated as GOP_X%) was developed. Low-field nuclear magnetic resonance analysis confirmed that GOP_X% containing AOPE exhibited increased hydrogen bonding crosslink density. At an AOPE loading of 6% (GOP_6%), the composite film exhibited exceptional improvements compared with GOP_0%: elongation at break increased by 107%, toughness increased by 167.5%, water vapor permeability decreased by 73.6%, and oxygen permeability reduced by 85.3%. Additionally, antibacterial and antioxidant properties were markedly enhanced. The Pickering emulsion effectively mitigated the damage of ultraviolet radiation and thermal effects on the bioactive properties of oregano essential oil. Overall, the incorporation of AOPE imparted the gelatin composite film with exceptional mechanical properties, barrier properties, antioxidant activity, and antibacterial activity, extending the shelf life of grass carp fillets by 3 days during storage. This sustainable and eco-friendly active packaging film offers a promising strategy for designing active packaging materials. Full article

Water pumps consume roughly 20% of global electricity, yet 60–70% of pumps operate below optimal efficiency, leading to substantial energy waste. Improving pump efficiency is therefore critical. A major contributor to these losses is the low efficiency of the driving motor at reduced speeds and the lack of variable-speed capability—especially in single-phase pumps. This paper presents a fuzzy-logic–FOC (field oriented control) permanent magnet synchronous motor (PMSM) pump system that can run on either three-phase or single-phase power. The system maintains high efficiency across a wide speed range and saves energy not only through variable-speed operation but also via an intelligent control strategy termed “constant flow, variable pressure.” To assess performance, we conducted experiments comparing the proposed fuzzy-logic FOC controlled PMSM pump and a conventional AC asynchronous induction motor pump. The results show that the new system overcomes the inherent lack of speed regulation in traditional single-phase pumps and significantly improves efficiency across diverse operating conditions. Moreover, by implementing the “constant flow, variable pressure” strategy, the system achieves average energy savings estimated at 30–50% compared with a conventional AC asynchronous motor-driven pump. Full article