Search Results (3,600)

This study introduced a new low-temperature storage method that applies an additional lower strength static electric field (SEF) under the condition of a static magnetic field (SMF) to investigate the impact of magneto–electric coupling on the supercooling degree and quality of beef. The results showed that 7 mT-1 kV performs the best (−5.8 °C); the ability of SMF to maintain supercooling is less affected by SEF. Moreover, on the 15th day, magneto–electric coupling (7 mT-1 kV) outperformed SMF (7 mT) alone by reducing beef pH by 0.27, decreasing total viable counts (TVC) by 0.87 log CFU/g, maintaining TVB-N at only 12.5 mg/100 g, and limiting oxidative change, calpain activity, and shear force variation. Magnetic resonance imaging revealed that magneto–electric coupling treatment stabilized the T₂ relaxation time in meat samples, effectively inhibiting immobilized water migration and promoting more uniform moisture distribution, highlighting its application potential as a low temperature preservation method. Full article

This article describes systems generating high-frequency rotating magnetic fields for magnetic hyperthermia treatments. It covers two- and three-phase device systems powered by rectangular signals. A passive bandpass filter tuned to a specific frequency (100 kHz) is placed between the magnetic circuits and the DC power source powering the device. The paper compares the electrical parameters of both solutions, including the supply voltage, magnetic field strength amplitude H, and magnetizing current I_L as a function of the supply voltage (U_dc). At a fixed supply voltage U_dc, the magnetizing current I_L and the rotating magnetic field strength amplitude H are approximately twice as large for the three-phase system as for the two-phase system. The relationships between the magnetizing currents I_L and the magnetic field strength amplitude H as a function of the supply voltage U_dc are linear. Full article

When the outer sheath of submarine cables is damaged, the degradation of cross-linked polyethylene (XLPE) insulation by anions in seawater becomes a critical factor affecting cable service life. This study investigates 500 kV three-core XLPE insulation and systematically reveals the differential and synergistic degradation mechanisms of major seawater anions (Cl⁻, SO₄²⁻, HCO₃⁻). Accelerated aging tests at 90 °C were conducted using solution systems simulating both single-ion and composite environments, combined with electrical performance evaluation, Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). Results show that seawater causes significantly greater deterioration of resistivity, breakdown strength, and molecular structure than any single-ion solution. Mechanistic analysis demonstrates that Cl⁻ induces nucleophilic substitution, SO₄²⁻ promotes oxidative chain scission, and HCO₃⁻ facilitates hydrolysis via pH regulation, while their coexistence produces nonlinear synergistic effects through oxidative reactions, electrochemical coupling, and ion transport. This work provides the first systematic comparison of individual and combined anion effects on XLPE, offering new mechanistic insights and quantitative evidence for understanding multi-ion degradation, with implications for insulation material design, protective strategies, and service life prediction of submarine cables. Full article

The field emission current in a vacuum ($I_T=\alpha E^2/e^{\beta /E}$, where $\mathsf{\alpha }$ and $\beta$ are constants) depends on the electric field strength E. In other words, the differential resistance ${(d{I}_T/dV)}^{-1}$ in a vacuum does not follow Ohm’s law. Therefore, the relationship governing the capacitance and current between two electrodes in a vacuum is an intriguing research topic. In this study, we constructed an interface structure in which contact areas and non-contact vacuum areas coexisted by adhering two Si wafers and measuring the capacitance characteristics of this structure. A volatile capacitance appeared at the interface, with the contact areas contributing to positive capacitance and the vacuum areas contributing to negative capacitance. The tunneling current passing through the interface played an important role in the formation of the negative capacitance. Full article

The electronic transport behavior in ferromagnetic thin films critically dictates the functionality and efficiency of devices in spintronics and modern materials science. This work characterizes terahertz (THz) responses and nonlinear conductivities of Fe ultrathin films under high-field THz excitation. We demonstrated that different nonlinearities are present for two different thickness samples. For a 2 nm thick Fe film, as the peak THz electric field was increased to 369 kV/cm, the THz transmittance of Fe films generally decreased. However, for the 4 nm thick Fe film, the THz transmittance is almost field strength independent. This result is correlated with the conductivity variations induced by carrier transport processes. The real part of the complex conductivity for the 2 nm thick film increased significantly with the THz electric field, while the 4 nm thick film showed negligible dependence. In addition, we extracted the frequency-domain complex conductivity of the Fe thin films and used the Drude or Drude–Smith model to explain the distinct behaviors between the two thickness samples under intense THz fields, mainly associated with the surface morphology. This work aims to elucidate the transport properties of Fe films in the THz frequency range. Our findings lay a crucial foundation for the design and development of future high-performance THz spintronic functional devices. Full article

This study analytically investigates shear horizontal (SH) wave propagation in a layered structure consisting of a piezoflexoelectric (PFE) layer bonded to an elastic substrate, considering an imperfect interface. A frequency equation is derived by applying appropriate boundary and interfacial conditions, capturing the effects of flexoelectric coupling, interface imperfections, the layer thickness, and the material properties. The resulting dispersion relation reveals that both interface imperfections and the flexoelectric strength significantly alter the phase velocity of SH waves. Numerical simulations show that increasing flexoelectric coefficients or interface imperfections lead to notable changes in dispersion behavior. Comparative analyses under electrically open (EO)- and electrically short (ES)-circuited boundary conditions demonstrate their impacts on wave propagation. These findings offer new insights into the design and analysis of piezoflexoelectric devices with realistic interface conditions. Full article

The effects of Cu content on the microstructure, texture, precipitates, and magnetic and mechanical properties of 0.20 mm-thick non-oriented silicon steel (3.0% Si-0.8% Al-0.5% Mn) were systematically investigated using optical microscopy, X-ray diffraction, electron backscatter diffraction, and transmission electron microscopy. The strengthening mechanisms of Cu-bearing high-strength non-oriented silicon steel were further elucidated. Increasing Cu content inhibited grain growth and suppressed the development of the α*-fiber texture in annealed sheets, while promoting the formation of γ-fiber texture. As a result, the P_1.0/400 and B₅₀ values deteriorated. The P_1.0/400 and B₅₀ values of 1.47% Cu non-oriented silicon steel were 13.930 W/kg and 1.614 T, respectively. However, due to the solid solution strengthening effect of 0.5% Cu and partial precipitation strengthening, the R_p0.2 increased by 43 MPa. After aging treatment at 550 °C for 20 min, the P_1.0/400 values of the aged sheets slightly increased, while the B₅₀ values remained almost unchanged. In the aged sheets containing 1.0–1.5% Cu, clustered Cu-rich precipitates with average sizes of 2.71 nm and 13.28 nm were observed. The crystal structure of these precipitates transitioned from the metastable B2-Cu to the stable FCC-Cu. These precipitates enhanced the R_p0.2 of the non-oriented electrical steel to 241 MPa and 269 MPa through cutting and bypass mechanisms, respectively. A high-strength non-oriented silicon steel with balanced magnetic and mechanical properties was developed for driving motors of new energy vehicles by utilizing nanoscale Cu-rich precipitates formed through aging treatment. The optimized steel exhibits a yield strength of 708 MPa, a magnetic induction B₅₀ of 1.639 T, and high-frequency iron loss P_1.0/400 of 14.77 W/kg. Full article

Cement-based materials are reliable materials that guarantee high efficiency and high performance and are one of the important materials for the civil engineering industries. It is an era in which carbon neutrality and energy efficiency are emphasized, and electric energy production is currently being challenged even in cement paste. At this time, the most difficult part is the process of efficiently manufacturing a positive type of P-type cement paste. In this study, a P-type cement paste impregnated with an acidic solution to remove the OH⁻ ions was prepared, and the Seebeck coefficient was obtained to confirm its electrical production capacity. In the case of cement, specimens impregnated with acetic acid and impregnated with undiluted solution for 48 h showed the highest value at 1270 µV/K, and those impregnated with pure lemon juice showed the highest value at 1220 µV/K. It is estimated that the compressive strength of the cement paste impregnated with pure lemon juice is about 10–40% greater than that of the cement paste impregnated with acetic acid, so the condition for producing the optimal P-type cement paste is to impregnate the pure lemon juice in a solution diluted to 20% for 48 h. This study provides the possibility of manufacturing P-type cement paste with optimal performance and manufacturing electric production cement using the Peltier effect in the future. Full article

Several types of self-balancing vehicles have been successfully developed and commercialized in the past two decades, both as manned vehicles and as autonomous mobile robots. At the same time, due to their characteristic instability and underactuation, a large body of research has been devoted to their control. However, despite this practical and theoretical interest, the current publicly available literature does not cover their systematic design and development. In particular, overall processes that lead to a finished vehicle starting from a set of requirements and specifications have not been examined in the literature. Within this context, this paper contributes a comprehensive mechatronic, dynamics-based procedure for the design of this class of vehicles; to promote clarity of exposition, the procedure is systematically presented using Model-Based Systems Engineering tools and principles. In particular, the proposed design method is developed and formalized starting from an original description of the vehicle, which is treated as a complex system composed of several interconnected multi-domain components that exchange power and logical flows through suitable interfaces. A key focus of this work is the analysis of these exchanges, with the goal of defining a minimal set of quantities that should be necessarily considered to properly design the vehicle. As a salient result, the design process is organized in a logical sequence of steps, each having well-defined inputs and outputs. The procedure is also graphically outlined using standardized formalisms. The design method is shown to cover all the mechanical, electrical, actuation, measurement and control components of the system, and to allow the unified treatment of a large variety of different vehicle variants. The procedure is then applied to a specific case study, with the goal of developing the detailed design of a full-scale vehicle. The main strengths of the proposed approach are then widely highlighted and discussed. Full article

With the increasing penetration of renewable energy, the stochastic and intermittent nature of its generation increases operational uncertainty and vulnerability, posing significant challenges for grid stability. However, traditional algorithms typically identify critical nodes by focusing solely on the network topology or power flow, or by combining the two, which leads to the inaccurate and incomplete identification of essential nodes. To address this, we propose the Three-Dimensional Value-Based Gravity Model (3V-GM), which integrates structural and electrical–physical attributes across three layers. In the plane layer, we combine each node’s global topological position with its real-time supply–demand voltage state. In the line layer, we introduce an electrical coupling distance to quantify the strength of electromagnetic interactions between nodes. In the point layer, we apply eigenvector centrality to detect latent hub nodes whose influence is not immediately apparent. The performance of our proposed method was evaluated by examining the change in the load loss rate as nodes were sequentially removed. To assess the effectiveness of the 3V-GM approach, simulations were conducted on the IEEE 39 system, as well as six other benchmark networks. The simulations were performed using Python scripts, with operational parameters such as bus voltages, active and reactive power flows, and branch impedances obtained from standard test cases provided by MATPOWER v7.1. The results consistently show that removing the same number of nodes identified by 3V-GM leads to a greater load loss compared to the six baseline methods. This demonstrates the superior accuracy and stability of our approach. Additionally, an ablation experiment, which decomposed and recombined the three layers, further highlights the unique contribution of each component to the overall performance. Full article

Graphene, a two-dimensional carbon material with a hexagonal lattice structure, possesses remarkable properties. Exceptional electrical conductivity, mechanical strength, and high surface area that make it a powerful platform for biosensing applications. Its sp²-hybridised network facilitates efficient electron mobility and enables diverse surface functionalisation through bio-interfacing. This review highlights the core detection mechanisms in graphene-based biosensors. Optical sensing techniques, such as surface plasmon resonance (SPR) and surface-enhanced Raman scattering (SERS), benefit significantly from graphene’s strong light–matter interaction, which enhances signal sensitivity. Although graphene itself lacks intrinsic piezoelectricity, its integration with piezoelectric substrates can augment the performance of piezoelectric biosensors. In electrochemical sensing, graphene-based electrodes support rapid electron transfer, enabling fast response times across a range of techniques, including impedance spectroscopy, amperometry, and voltammetry. Graphene field-effect transistors (GFETs), which leverage graphene’s high carrier mobility, offer real-time, label-free, and highly sensitive detection of biomolecules. In addition, the review also explores multiplexed detection strategies vital for point-of-care diagnostics. Graphene’s nanoscale dimensions and tunable surface chemistry facilitate both array-based configurations and the simultaneous detection of multiple biomarkers. This adaptability makes graphene an ideal material for compact, scalable, and accurate biosensor platforms. Continued advancements in graphene biofunctionalisation, sensing modalities, and integrated multiplexing are driving the development of next-generation biosensors with superior sensitivity, selectivity, and diagnostic reliability. Full article

This study investigates the effect of seasonal conductor sag on electromagnetic field (EMF) exposure to near 400 kV double-bundle overhead transmission lines. The conductor sag study resulted in clearance values of 28.0 m for winter (−10 °C, sag ≈ 7.0 m) and 23.4 m for summer (+35 °C, sag ≈ 11.65 m). For both seasonal examples, the electric field strength and magnetic flux density were calculated at a pedestrian height of 1.5 m, and the image approach to account for ground effects. The winter setup resulted in maximum values of 1.35 kV/m (E) and 27.2 µT (B), while the summer configuration produced higher values of 1.96 kV/m and 38.5 µT, respectively. Autumn field measurements, representing intermediate seasonal circumstances, produced average values of 1.294 kV/m and 1.399 µT, with peaks of 8.39 kV/m and 6.85 µT for electric field and magnetic flux density, respectively. The electric field projections were nearly identical to measurements; however, the magnetic field predictions were significantly higher, most likely due to the model’s assumptions of balanced currents and ideal geometry. These findings suggest that seasonal conductor sag variation is a real and substantial factor in assessing EMF exposure, with the electric field being particularly sensitive to clearance changes. The findings emphasize the need to incorporate a large analysis into EMF compliance assessments, especially in cases where terrain relief between towers may further diminish clearance in mid-span regions. Full article

The influence of polar ice-covered environments on the corrosion-related static electric field (CRSE) of underwater vehicles is critical for understanding and applying the characteristics of underwater electric fields in polar regions. This study utilizes a combined methodology involving COMSOL Multiphysics 6.1 simulations and laboratory-simulated experiments to systematically investigate the distribution characteristics of underwater vehicle electric fields under ice-covered conditions. By comparing the electric field distributions in scenarios with and without ice coverage, this study clarifies the effect of ice presence on the behavior of underwater electric fields. The simulation results demonstrate that the existence of ice layers enhances both the electric potential and field strength, with the degree of influence depending on the ice layer conductivity, thickness, and proximity of the measurement points to the ice layer. The accumulation of error analysis and laboratory experiments corroborates the reliability of the simulation results, demonstrating that ice layers enhance electric field signals by modifying the conductive properties of the surrounding medium, whereas the overall spatial distribution characteristics remain largely consistent. These findings offer a theoretical and technical basis for the optimization of stealth strategies in polar underwater vehicles and contribute to the advancement of electric field detection technologies. Full article

The ocean harbors vast potential for oil and gas resources, positioning offshore drilling as a critical approach for future energy exploration. However, high-temperature and high-pressure offshore reservoirs present formidable challenges, as conventional water-based drilling fluids are prone to thermal degradation and rheological instability, leading to wellbore collapse and stuck-pipe incidents. Offshore oil-based drilling fluids (OBDFs), typically water-in-oil emulsions, offer advantages in wellbore stability, lubricity, and contamination resistance, yet their stability under extreme high-temperature conditions remains limited. This study reveals the enhancement of offshore OBDFs performance in harsh conditions by employing nano-SiO₂ to synergistically improve emulsion film stability and non-Newtonian rheological behavior while systematically elucidating the underlying mechanisms. Nano-SiO₂ forms a composite film with emulsifiers, reducing droplet size, enhancing mechanical strength, and increasing thermal stability. Optimal stability was observed at an oil-to-water ratio of 7:3 with 2.5% nano-SiO₂ dispersion and 4.0% emulsifier. Rheological analyses revealed that nano-silica enhances electrostatic repulsion, reduces plastic viscosity, establishes a network structure that increases yield stress, and promotes pronounced shear-thinning behavior. Macroscopic evaluations, including fluid loss, rheological performance, and electrical stability, further confirmed the improved high-temperature stability of offshore OBDFs with nano-SiO₂ at reduced emulsifier concentrations. These findings provide a theoretical basis for optimizing offshore OBDFs formulations and their field performance, offering breakthrough technological support for safe and efficient drilling in ultra-high-temperature offshore reservoirs. Full article

This study investigates the potential of corn stover, an abundant agricultural byproduct, as a sustainable additive in concrete masonry units (CMUs). Preliminary trials were conducted to determine the optimal fiber length (~3 mm and ~10 mm), fiber content (0%, 1%, 3%, and 5% by volume), and alkalinization method (soaking in 0.5 M NaOH, KOH, or synthetic concrete pore solution) for corn stover fibers (CSFs). The results indicated that short fibers treated with synthetic concrete pore solution yielded the best compressive strength and workability, and were thus selected for the main study. A novel mixture was developed by replacing 10% of cement with corn stover ash (CSA) and incorporating 1% alkaline-treated CSF by volume. The resulting blocks (termed “Corncrete”) were evaluated for mechanical and durability properties, including strength, water absorption, bulk and surface electrical resistivity, rapid chloride permeability (RCPT), and fire resistance. Compared to conventional CMUs, Corncrete exhibited an 11–13% reduction in 28- and 91-day compressive strength, though the difference was statistically insignificant. Physically, Corncrete had a 4.4% lower bulk density and a 7.9% higher total water absorption compared to the control. However, its water absorption rates at early stages were 32% and 48% lower, indicating better resistance to moisture uptake shortly after exposure. Durability tests revealed a 13.7% reduction in chloride ion permeability and a 33% increase in bulk and surface electrical resistivity after 90 days. Fire performance was comparable between the two mixtures, with both displaying ~10.5% mass loss and ~5% residual strength after high-temperature exposure. These findings demonstrate that Corncrete offers balanced mechanical performance and enhanced durability, making it a viable eco-friendly option for non-structural masonry applications. Full article