Search Results (759)

Urban roundabouts present significant design challenges for the integration of micro-mobility, yet comparative evidence regarding user behavior remains limited. As cities transition toward sustainable transport networks, understanding the operational needs of different micromobility modes is essential for urban planning. This study investigates the dynamic strategies of micromobility users through a controlled field experiment at a mini-roundabout in Gravina di Catania, Italy. Twenty experienced riders executed crossings using conventional bicycles and electric scooters. Utilizing drone recordings and open-source tracking, the analysis extracted speed, longitudinal acceleration, and path radius across 80 maneuvers. The findings reveal that behavior is highly dependent on vehicle type and geometric deflection. On highly deflected trajectories, e-scooters selected wider radii and achieved up to 15% higher speeds and accelerations than bicycles, whereas on gentler trajectories, they adopted more conservative, tighter lines with intense braking. Bicycles exhibited smaller, less systematic adjustments. These significant kinematic differences indicate that bicycles and e-scooters possess distinct performance envelopes. Treating them as a single legal or design class obscures stability disparities influencing conflict risk. Ultimately, this research provides empirical insights to guide urban planners in redesigning intersections, emphasizing that tailored infrastructure and targeted speed management are critical steps toward safer, truly sustainable urban mobility. Full article

This article presents the design and characterization process of a lightweight Vivaldi antenna for high-voltage ultra-wideband systems. The proposed antenna consists of two radiating arms with different exponential curves on their inner and outer edges fed with an insulated-coplanar-plates transmission line. Weight reduction is achieved by implementing the antenna with sheets composed of a polyester layer between two aluminum layers, with a polylactic acid insulator inserted between the arms. The reflection coefficient of the implemented antenna demonstrates an impedance bandwidth ranging from 0.61 GHz to 3.44 GHz. High-voltage operation of up to 12.4 kV is also experimentally demonstrated. In addition to satisfying the high-voltage and ultra-wideband operational requirements, the proposed antenna is shown to achieve, among antennas with comparable characteristics, the most effective combination of low minimum operating frequency and low weight. The transfer function between the voltage applied to the antenna, $V_s$, and the radiated electric field, $E_r$, is measured. Using this transfer function, the radiated electric field is calculated for an input voltage pulse with a rise time of 110 ps to confirm the antenna’s capability of producing radiated pulses with low distortion. The calculated radiated electric field pulse closely matches the results obtained with full-wave simulation. To assess the similarity between the radiated and applied pulses, the pulse width stretch ratio is calculated, yielding a variation of 3.86% for the direction of maximum gain and 9.36% for 30° in the H-plane of the antenna. This feature is desirable for EMC, EMI and sensing applications. The antenna is also characterized in the frequency domain, achieving a maximum gain of 10.09 dBi at 3.63 GHz and a 30° 3 dB beamwidth for ultra-wideband pulses. Full article

Background: Electrochemotherapy enhances the intracellular delivery of anticancer agents through electroporation but is traditionally limited to cytotoxic drugs associated with significant side effects. Vitamin C (ascorbic acid) exhibits selective anticancer activity when accumulated at high intracellular concentrations; however, its therapeutic application is restricted by poor membrane permeability and rapid systemic clearance. Methods: In this study, we investigated whether reversible electroporation, applied using a custom-designed variable plate electrode system designed to deliver a uniform electric field, could potentiate the antitumor efficacy of low-dose vitamin C. Numerical simulations were performed to optimize electrode spacing and stimulation voltage, suggesting homogeneous electric field coverage throughout the tumor volume. The proposed approach was evaluated in vitro using MDA-MB-231 and 4T1 breast cancer cell lines and in vivo in a 4T1 murine breast cancer model. Results: Low-dose vitamin C alone produced minimal cytotoxic effects, whereas its combination with electroporation significantly reduced cell viability and increased apoptotic and necrotic cell death in vitro. In vivo, vitamin C–assisted electrochemotherapy resulted in pronounced tumor growth suppression, with tumor volumes reduced to approximately 0.34-fold of baseline by day 15, accompanied by decreased proliferation and marked tissue disruption. Conclusions: These findings demonstrate that uniform-field reversible electroporation markedly enhances the intracellular delivery and antitumor activity of low-dose vitamin C, supporting this technology-driven strategy as a promising, low-toxicity alternative to conventional chemotherapeutic agents in electrochemotherapy for solid tumors. Full article

With the growing simultaneous demands for miniaturization and high performance, thermal issues such as hotspots severely degrade the high-speed signal transmission performance of low temperature co-fired ceramic (LTCC) substrate in system-in-package (SiP) modules. This paper proposes a high-speed transmission line design for LTCC substrates, using a G-S (Ground-Signal) structure to ensure reliable signal transmission quality. Based on this structure, finite element simulations are performed to investigate the electromagnetic signal transmission characteristics under both uniform and non-uniform thermal fields, confirming that signal transmission efficiency exhibits strong temperature dependence. The results indicate that when the temperature exceeds 50 °C, non-uniform temperature distributions exert a significantly stronger influence on electromagnetic performance, leading to aggravated signal reflections and reduced transmission efficiency. At 300 °C, the transmission efficiency under non-uniform temperature drops to 35.0%, which is a 61.8% decrease compared with the optimal scheme obtained under ideal electric field conditions. Under electromagnetic-thermal coupling, a comparative study of different schemes shows that the optimal design derived from a single electric field is not suitable for electromagnetic-thermal coupled working conditions. The optimized Scheme 2 increases transmission efficiency to about 75.3%, with smoother S-parameter curves and smaller fluctuations. These findings provide valuable references for subsequent reliability-oriented design and experimental verification. Full article

To accurately evaluate the electric and magnetic field distribution characteristics around transmission lines under different tower structures and operating conditions, this study systematically investigates the spatial electric and magnetic fields of transmission line towers based on Grid Information Model (GIM) file parsing and finite element simulation. First, key information, including tower geometric configuration, conductor suspension point locations, and voltage level, is extracted by parsing the GIM file. A unified transformation method from geographic coordinates to three-dimensional Cartesian coordinates is established, and a three-dimensional electric and magnetic field calculation model is constructed in the ANSYS Maxwell platform, incorporating a catenary conductor model and an equivalent representation of bundled conductors. Furthermore, the accuracy of the proposed calculation method is validated based on field measurement data. Second, under single-circuit operating conditions, the spatial electric and magnetic field distributions of the Goblet-shaped suspension tower and the Drum-type transmission tower are analyzed under different phase sequence arrangements and different conductor-to-ground heights, and the shielding effect of the tower structure on the local electric field is investigated. On this basis, an electric field fitting method based on a proportional polynomial model is proposed, enabling the prediction of electric field distribution under tower-present conditions using simulation results obtained without tower structures. Subsequently, the influence of different phase sequence combinations on the spatial electric field distribution is systematically examined. The fitting method is further extended to double-circuit transmission lines, and its accuracy and effectiveness in rapid electric field assessment are verified. Finally, from an engineering practice perspective, the effects of the presence of jumper conductors and variations in conductor turning angles on the spatial electric field distribution of double-circuit towers are analyzed, and an optimized estimation approach for electric fields under different turning angle conditions is proposed. The results demonstrate that tower structural configuration and conductor arrangement significantly affect the electric field distribution, and the proposed fitting method effectively reduces modeling complexity while maintaining computational accuracy. The findings of this study provide a theoretical basis and technical reference for electric and magnetic environment assessment and engineering design of transmission lines. Full article

Globally, the transport sector accounts for almost a quarter of CO₂ emissions from fuel combustion and generates large amounts of pollutants, placing significant pressure on the environment and human health. By 2050, the European Green Deal requires a 90% reduction in transport-related emissions, making sustainability necessary across all modes of transport. Based on the relevant literature, this study examines the role and potential of railways in decarbonising the EU transport sector. Railway is highly efficient, consuming just 1.9% of transport sector energy while handling 16.9% of freight and 5.1% of passenger transport in the EU, yet is responsible for only 0.4% of total emissions. According to studies, greenhouse gas emissions can be reduced by improving energy efficiency, using low-carbon or renewable energy, and expanding train electrification. The greatest potential for decarbonisation lies in a modal shift to rail. However, this requires significant infrastructure investment: raising line speeds to at least 160 km/h, expanding networks, building terminals, digitalisation, and alignment with TEN-T standards. Although the EU supports the modal shift with funding programmes, the transition is not progressing as expected—the share of road freight transport increased from 74% in 2013 to 78% in 2023. Stronger investment is needed in Member States’ national policies for the development and modernisation of railways. The authors developed a Path Evaluation Matrix (PEM), a quantitative decision framework integrating the fields of energy, transport, politics, and economics. The PEM results indicate that BEMU (battery electric multiple units) is optimal for 68% of secondary lines in south-eastern Europe. Full article

This study conducts an in-depth investigation into the left–right lifting height deviation in the main lifting and lining device of the SQS-300K tunnel and bridge clearance cleaning vehicle under specific working conditions. Through field measurements and theoretical analysis, the research highlights the typical characteristics of this issue in transition curves (with a maximum deviation of 50 mm) and its adverse effects on track geometry. A systematic hydraulic–electrical synergistic optimization scheme using independent cylinder control is proposed to address the problem. Field tests show that the maximum deviation is reduced to below 10 mm after optimization. The findings not only resolve the technical challenges encountered in the field application of the SQS-300K machine but also provide a theoretical foundation and practical technical support for the optimized design, precise control, and condition maintenance of lifting and lining devices in similar large-scale railway maintenance machinery. This contribution is significant for ensuring railway operational safety. Full article

With the increasing density of transmission lines, line crossings and spans have become more common, and the electromagnetic environment of transmission lines has attracted increasing attention. Investigating the electromagnetic field distribution in transmission line crossing regions is therefore of great significance for line layout and preliminary design. In this study, the parameters of transmission lines in crossing regions are first obtained by parsing the GIM (Grid Information Model) file. A three-dimensional electromagnetic field model of a double-circuit transmission line on the same tower is then established using the finite element method, and the accuracy of the proposed approach is validated by comparison with field measurement data. Based on the developed model, the electric and magnetic field distributions of both the double-circuit transmission line and the crossing region are calculated. Furthermore, the effects of different crossing angles, phase sequence combinations, and voltage levels on the electromagnetic field distribution are systematically investigated. By comparing the electromagnetic field characteristics under different phase sequence schemes, an optimized phase sequence configuration for double-circuit transmission lines and crossing regions is proposed. The results provide a theoretical basis and technical reference for electromagnetic environment assessment and design optimization of transmission lines in crossing regions. Full article

Using satellite observations and computed variables, we specified 5 Subauroral Polarization Stream (SAPS) and 28 Subauroral Ion Drift (SAID) events observed in the Northern Hemisphere by spacecraft F18 in 2013. These SAPS-SAID flows reached supersonic velocities (2400–5200 m/s), were driven by westward E × B ion drifts generated by their underlying strong poleward meridional SAPS-SAID electric (E) fields (90–190 mV/m) and northward geomagnetic B fields, and developed at high (≥68°) magnetic latitudes, in the dusk sector, sometimes on the dayside, and mostly within the downward region-2 current suggesting their previous development. Within the deepening main trough, the poleward SAPS/SAID E field increased directly with the reductions in plasma density and conductivity, suggesting positive feedback mechanisms in progress. Across the highly inclined magnetic field lines within the subauroral flow channel, the eastward/westward zonal E field E × B drifted ions equatorward/poleward and yielded large upward/downward ion drifts observed by F18. Earthward energy deposition into the SAPS and SAID channels indicates magnetospheric electromagnetic energy generations in their respective voltage generators. Conjugate observations depict the large outward SAID E field (|E_X ≈ 10 mV/m|) on 28 October 2013 and SAPS E field (|E_Z ≈ 10 mV/m|) on 14 October 2013 developed at L ≈ 10 R_E on a short timescale at dusk. Full article

We developed an arbitrary Lagrangian–Eulerian (ALE)-based multiphysics model for evaporation from a contact-line-pinned sessile drop of neat water subject to a vertically oriented sinusoidal alternating current (AC) electric field applied across parallel-plate electrodes. The framework fully couples electrostatics, incompressible flow, heat transfer with evaporative cooling, and transient vapour transport in air, and includes an instantaneous, voltage-controlled electrowetting contact-angle response under constant-contact-radius conditions. Validation against published data shows that the model captures both pinned-droplet evaporation and electrically induced deformation. Because Maxwell traction scales with the squared electric-field magnitude, droplet height and contact angle exhibit a robust 2:1 frequency-doubled response, producing two peak–trough events per voltage period. The resulting periodic deformation drives oscillatory interfacial shear and internal recirculation, yielding a synchronous double-peaked evaporative-flux waveform. Gas-side analysis quantifies a time-varying diffusion-layer thickness via a characteristic diffusion length; two thinning events per period coincide with flux maxima, indicating that AC enhancement is dominated by periodic compression of the vapour boundary layer and reduced gas-side mass-transfer resistance. Increasing voltage amplitude (0–60 kV) strongly accelerates volume loss, while frequency has a secondary effect: the cycle-averaged flux rises from 1 to 10 Hz but decreases slightly at 20 Hz due to phase lag and weaker boundary-layer modulation. Full article

To address the low efficiency of finite element modeling and the reliance on manual measurements in electric/magnetic field analysis of complex overhead transmission line structures, this paper develops an IronPython-based automated computational platform within ANSYS Maxwell for 3-D modeling and electric/magnetic field analysis. First, by parsing transmission line data from the Grid Information Model (GIM), a unified coordinate transformation method is proposed to convert geographical coordinates into three-dimensional (3-D) Cartesian coordinates for finite element analysis. Based on the extracted line parameters, conductor sag is calculated and catenary modeling is implemented. An equivalent radius method is also introduced to simplify multi-bundle conductor modeling, enabling fast parametric construction of complex 3-D transmission line models. Second, by combining the IronPython scripting language with the .NET Windows Forms control library, a visualized finite element modeling and computation platform is developed. Finally, a typical double-circuit transmission line on the same tower is taken as a case study to calculate the spatial distribution of electric/magnetic fields. The influence of solution domain size on electric/magnetic field computation results is investigated, and optimal solution domain parameters are determined. The finite element results generated by the developed platform are further validated through comparison with measured data. The results demonstrate good agreement between calculated and measured values, confirming the accuracy and engineering applicability of the developed platform for electric/magnetic environment analysis of overhead transmission lines. Full article

Lightning-induced breaking accidents of medium-voltage insulated conductors pose a serious threat to the safety of distribution networks, and the key cause lies in the establishment and sustained combustion of the power-frequency follow-current arc after lightning overvoltage breakdown. This paper systematically investigates the formation mechanism and critical conditions of power-frequency follow-current arcs using combined simulation and experimental approaches. Based on the streamer discharge theory, a lightning breakdown model was established and combined with the arc energy balance equation, revealing that the establishment of power-frequency follow-current arcs is essentially determined by the post-breakdown energy competition process. The simulation results show that the required anode electric field strength for lightning breakdown is not less than 3 kV/mm. When the power-frequency voltage reaches 10 kV, Joule heating of the arc continuously exceeds heat dissipation loss, enabling restrike after zero-crossing and sustaining stable burning. Experiments verified this voltage threshold and further revealed that the arc establishment rate exhibits nonlinear growth with increasing power-frequency voltage, exceeding 90% at power-frequency voltages ≥ 10 kV. The study also reveals that increased gap distance reduces the arc establishment rate, while the introduction of insulators can enhance it by approximately 20%. This study clarifies the energy criterion for power-frequency follow-current arc establishment and the influence patterns of key parameters, providing theoretical basis and engineering reference for lightning protection design and arc suppression in medium-voltage insulated lines. Full article

Metallic contaminants in powdered foods represent a serious safety concern. Therefore, effective detection is crucial for food safety. This study aimed to develop an electric-field-based detection system and quantitatively evaluate its performance. An alternating (+/−) electrode array (gap 1–2 mm) was designed, and resonance analysis identified 15 kHz with a 2 mm gap as the optimal operating condition. Using an IGBT-based high-voltage source, 1.35 kV was selected to ensure stable operation without partial discharge. A real-time algorithm based on a minimum current-change threshold was implemented, and detection responses to stainless steel (SUS), aluminum (Al), and copper (Cu) particles in three size classes (<0.5, 0.5–1.0, and 1.0–2.0 mm) were evaluated using hit/miss modeling and logistic regression to obtain probability-of-detection (POD) curves and limits of detection (LOD). The system achieved POD ≥ 0.9 for 1.0–2.0 mm particles; in the 0.5–1.0 mm range, observed POD values were 84%, 90%, and 68% for SUS, Al, and Cu, respectively. Safety was assessed by COMSOL-based localized heating simulation validated by infrared thermography and by ozone monitoring for real-time operation. Compared with conventional inspection approaches, the proposed system provides a compact, cost-effective architecture while reporting inspection-oriented reliability metrics (POD/LOD) for process-line deployment. Full article

Voltage status monitoring of transmission lines is critical for the safe operation of power systems. Traditional contact-based measurement methods pose safety risks and incur high costs. Therefore, this paper proposes a non-contact voltage Measurement method by inferring the actual voltage level of transmission lines. Firstly, the spatial electric field strength is constructed based on the simulated charge method. Then, the voltage of transmission lines is inverted according to the near-surface electric field strength. By incorporating Tikhonov regularization with multi-physical condition constraints and multi-start optimization strategies into traditional genetic algorithms, the instability issues in electric field inversion methods are resolved. The results indicate that under a 5% measurement noise, the voltage amplitude error is below 5%, and the phase error is less than 5°. The proposed improved genetic algorithm enhances the stability and reliability of the inversion process, providing an effective solution for voltage state monitoring of transmission lines. Full article

Insulators in wind-sand flows distort the electric field along their surfaces due to the wind-sand electric field, threatening the safe operation of transmission lines. This paper models the impact of wind and sand flow on electric field distribution along transmission line insulators by integrating an Eulerian two-fluid field with an electrostatic field, incorporating the electrification process of sand particles. The study investigates how different wind speeds, dust concentration, and sand particle sizes affect the electric field distribution on insulators. The results show that the electric field along the insulator’s surface decreases in steps, while the electric field forms a “U”-shape with high ends and a low center. In contrast to the clean environment, wind and sand flow generally increases the electric field. Under the influence of wind-sand flows, each 2 m/s wind speed rise reduces the electric field by about 2–3%. As sand concentration and particle size grow, the electric field decreases near the high-voltage end and increases near the grounded end. Higher concentrations or larger particles significantly boost the maximum electric field intensity, worsening distortion and increasing long-term insulation risks. Full article