Advancing Open Science

Accurate prediction of the zero-sequence impedance ($Z_0$) of three-legged zigzag grounding transformers is essential for ground-fault protection and power-quality performance, yet manufacturer analytical estimations often have limited accuracy. This paper investigates how accurately $Z_0$ can be predicted using 3D finite element method (FEM) models based on the stored magnetic energy approach and how modeling the metallic tank and nonlinear core B–H behavior affects $Z_0$ relative to analytical calculations and laboratory measurements. Two 3D FEM models are developed for a three-legged zigzag grounding transformer, incorporating the nonlinear core characteristic; impedance boundary conditions are used to efficiently account for tank-induced currents while reducing computational cost. The FEM results are compared with laboratory tests and with the analytical method used by manufacturers. The proposed models achieve errors below 4% with respect to the nominal $Z_0$ and outperform the analytical approach. The contributions are a validated 3D FEM methodology that resolves zero-sequence flux paths under fault conditions and a practical modeling tool that improves grounding transformer design and ground-fault protection settings in modern power systems.

Coordinated mitigation of greenhouse gases (GHGs) and air pollutants (APs) offers an effective strategy to address climate and air quality challenges, yet systematic evaluations in medium-sized industrial cities remain limited, despite their coal-dependent energy systems and emission-intensive manufacturing that disproportionately shape national emission trajectories. Thus, this study focuses on Weifang, a representative industrial city in Shandong Province, developing a high-resolution, multi-pollutant inventory and applying quantitative synergy indices to characterize emission patterns, sectoral contributions, and hotspot regions. In 2023, Weifang’s total emissions comprised 114.54 million metric tons (Mt) CO₂, 121.91 thousand metric tons (kt) CH₄, and 27.67 kt N₂O, alongside major APs including CO (662.99 kt), TSP (154.44 kt), and NOx (100.83 kt). Industrial sources and electricity-heat production contributed over 80% of CO₂ and SO₂, while agriculture dominated CH₄ (59.5%) and N₂O (40.5%). Mobile sources accounted for 66.6% of NOx, over 20% of VOCs, and 61.4% of CO. Spatially, suburban areas produced over 65% of total emissions due to heavy industry and agriculture, whereas the urban core exhibited higher intensities but lower total contributions. Bivariate and integrated synergy indices revealed stronger SO₂-NOx-CO₂ synergies in the urban core, while suburban emissions were more heterogeneous and spatially dispersed. Synergy analysis indicated strong SO₂-CO₂ co-variation from shared industrial sources but weak NOx-CO₂ correlations due to divergent origins. Hotspot mapping identified industrial parks, power plants, steel zones, and suburban agriculture as priority control areas. These findings demonstrate that source-specific measures are critical to maximizing co-benefits. The proposed methodological framework offers transferable insights for evaluating emission synergies in other industrial cities.

River regulation and embankment construction have fundamentally altered the hydrological relationships and sediment accumulation dynamics of floodplains worldwide. This study examines the accumulation conditions in the Upper Tisza (Hungary) floodplain, focusing on the different surface development conditions of oxbow lakes and fossil natural levees following human intervention. During the study, we integrated high resolution LIDAR terrain models with detailed sedimentological analyses (grain size composition, pH, EC, OC, CaCO₃). We used multivariate statistical methods (principal component and cluster analysis) to separate soil formation processes and sediment accumulation. Based on our results, we identified sharp sedimentological boundaries indicating artificial meander cutting (1852). We demonstrated that the cut meanders function as sediment traps, where the accumulation of fine grained sediments is significantly faster (>0.34 cm/year) than on the higher elevation natural levees (0.1 cm/year). Statistical analysis identified five distinct sedimentation environments, successfully separating recent soil levels from river sediments. These results provide an important basis for the complex management of floodplains, such as flood protection, water retention, and habitat management planning.

In this report, we describe the synthesis and full spectroscopic characterization of a previously unreported podophyllotoxin (PTOX) analogue bearing a second 3,4,5-trimethoxyphenyl (TMP) unit at the C-4 position through an ester linkage. This dual-TMP PTOX derivative is obtained from a brominated PTOX intermediate. In this precursor, the bromine atom is located on the TMP aromatic ring at the 2′-position. The new compound was fully characterized by proton (¹H), carbon-13 (¹³C), heteronuclear single-quantum coherence (HSQC), and distortionless enhancement by polarization transfer (DEPT) NMR spectroscopy. Ultraviolet–visible (UV-Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy, mass spectrometry and elemental analysis were also performed to confirm the structure and purity of the synthesized ester derivative.

Physical Education (PE) in primary education seems to be a privileged context for working on psychosocial factors, and the Sports Education Model (SEM) is of interest because of its potential in this regard. The purpose of this study was to conduct a systematic review to analyse the influence of the SEM on the psychosocial factors of primary school students. A systematic review based on the PRISMA guidelines was conducted using the Web of Science, Scopus, SportDiscus, ERIC and PsycInfo databases. The review analysed scientific literature examining the relationship between the SEM in Primary PE and psychosocial factors. The results found in the 20 articles included indicated that the SEM has a positive influence on psychosocial factors. The main conclusion is that this model may be of interest for the development or improvement of psychosocial factors in primary school students

Wood-based particleboards are a key component of sustainable building materials due to their renewable and low-carbon nature. However, their susceptibility to microbial contamination poses a significant challenge to indoor environmental quality and durability, limiting their alignment with the principles of a healthy and circular built environment. In this study, a sustainable antibacterial modification strategy was developed by employing natural montmorillonite (MMT) as a renewable mineral carrier to address the challenge. A synergistic antibacterial agent (Cu²⁺/ZnO@MMT-O) was engineered via ion exchange and co-precipitation, effectively immobilizing Cu²⁺ ions and ZnO nanoparticles within the MMT structure. This process preserved the layered structure of the carrier while simultaneously enhancing its specific surface area and mesoporosity. Antibacterial tests revealed that the Cu²⁺/ZnO@MMT-O exhibited markedly higher antibacterial activity against Escherichia coli and Staphylococcus aureus than single-component counterparts, indicating a pronounced synergistic effect. At an additive loading of 1.25%, the particleboards exhibited antibacterial rates exceeding 99% against both tested bacteria, while their mechanical properties (MOR 10.65 MPa, MOE 2304.40 MPa, and IB 0.29 MPa) and dimensional stability (24 h TS 16.31%) compliant with national standards. Overall, this work presents a practical and sustainable approach to enhancing the hygienic performance of renewable wood composites through the integration of mineral carriers with synergistic nanoscale antibacterial mechanisms, thereby contributing to healthier indoor environments and the development of green and healthy residential materials.

Mass M (kg) and peak intrusion L (mm) are jointly minimized for a CFRP-enabled battery pack enclosure under the GB 38031-2025 −40° side-pole extrusion condition. A 50-run explicit FE design of experiments is conducted and deterministically partitioned into 37/5/5/3 for initial training, two sequential enrichment batches, and an independent hold-out test. Bayesian additive regression trees are trained as the primary surrogates for M, L, and Stress, and stress acceptability is enforced through a probability-of-feasibility (PoF) gate anchored to a baseline-scaled cap, σ_lim = 1.2 σ_base = 410.4 MPa. NSGA-II performed on the feasible surrogate landscape yields a bimodal feasible non-dominated set. The two branches correspond to two discrete levels of a key thickness variable x₄: a low-mass regime (n = 106) with M = 100.61–104.81 kg and L = 5.430–5.516 mm at x₄ ≈ 5.60 mm, and a stiffer regime (n = 94) with M = 110.69–115.08 kg and L = 5.362–5.430 mm at x₄ ≈ 8.00 mm. PoF screening eliminates part of the intermediate region where feasibility confidence is insufficient. Independent FE reruns further indicate that the PoF gate reduces deterministic misclassification near the stress boundary (e.g., one near-threshold candidate exceeds σ_lim, whereas others satisfy the cap with margin). Overall, the proposed workflow offers a traceable lightweighting route under extreme-cold uncertainty within a constrained FE budget.

The continued growth of electric vehicle (EV) deployment has placed increasing emphasis on the development of charging infrastructure that is efficient, reliable, and compliant with safety requirements over a wide range of power levels. In EV charging systems, DC–DC converters work as a key interface for voltage adaptation, power regulation, and battery protection, making the choice of converter topology a crucial design consideration. This study provides a comparative and application-focused review of commonly employed isolated and non-isolated DC–DC converter topologies used in EV charging architectures. The comparison is carried out by examining voltage gain behavior, efficiency tendencies, switching and thermal stress, soft-switching capability, component utilization, control complexity, cost-related aspects, and practical deployment constraints. Fundamental operating principles and representative time-domain simulations are used to highlight relative performance trends of PWM-based and resonant isolated converters under typical charging conditions. Rather than introducing new converter structures or control methods, the objective of this work is to offer practical, design-oriented insights that support informed topology selection. Based on the comparative analysis, non-isolated converters are found to be well suited for low- to medium-power onboard charging applications, whereas isolated resonant converters are more appropriate for high-power and fast-charging systems when safety, scalability, efficiency trends, and system-level implementation factors are considered together.