Search Results (4,394)

The impact freezing of supercooled water droplets poses a significant threat to the safety of aircraft and power transmission equipment. In recent years, extensive research has been conducted using numerical methods to investigate this phenomenon. However, existing models often incorrectly predict premature freezing near the droplet–air contact line during the early stage of impact, thereby unreasonably suppressing the spreading process in these regions. To address this limitation, this study proposes a velocity-gate-based activation control strategy for the Darcy momentum source, enabling its dynamic adjustment during simulation. The methodology integrates the Volume of Fluid (VOF) model, the solidification model, and the dynamic contact angle (DCA) model with the proposed dynamic Darcy source, while accounting for the influence of supercooling on physical properties. The numerical simulations are performed using COMSOL Multiphysics 6.3 and validated against experimental spreading factor data. The results demonstrate that the proposed methodology effectively eliminates nonphysical freezing during the initial spreading stage, and the predicted spreading factors agree well with experiments, with a maximum relative deviation of up to 11.7% across all simulated cases. The proposed approach improves consistency with real-world behavior and enhances the reliability of existing numerical tools for aircraft icing prediction and anti-icing design. Full article

Mesoporous silica nanoparticles have been synthesized through sol–gel synthesis in basic conditions. Gemini surfactants having urea in the headgroups were used as pore-forming agents. The effect of the spacer length of the surfactant on the particle morphology was studied on the sub-micrometer and nanometer scales using nitrogen porosimetry, small-angle X-ray scattering (SAXS), ultra-small-angle neutron scattering, and scanning and transmission electron microscopy (SEM, TEM). Depending on the spacer, spherical and/or cylindrical nanoparticles formed in different proportions, as revealed by statistical analysis of SEM micrographs. All prepared materials showed the hexagonal pore structure characteristic of the MCM-41 molecular sieves, with the exception of the sample prepared using the gemini surfactant with the shortest spacer length. The influence of the spacer length on the lattice parameter of the pore network, as well as the average size of the ordered domains, has been assessed by SAXS and TEM. Detailed analysis of the TEM images revealed a spread of the lattice parameter in a range of 10–20%. The broadening of the diffraction peaks was shown to be due to the combination of the effects of the finite domain size and the variance of the lattice parameter across the crystalline domains. The structural differences between the silica gels synthesized with the different surfactants were related to the variation of the micelle morphologies, reported in previous light scattering and small-angle scattering experiments. No connection could be revealed between the micelle shape and size and the pore sizes, showing that surfactants with a broad range of spacer lengths can equally well be used for the preparation of MCM-41 materials. Full article

Human amniotic epithelial cell-derived exosomes (hAECs-Exos) are nanoscale extracellular vesicles with neuroprotective, regenerative, and anti-inflammatory properties, presenting a promising cell-free therapeutic approach for ischemic stroke. This study investigated the protective effects of hAECs-Exos against ischemic injury and explored the underlying molecular mechanisms. An optimized oxygen-glucose deprivation/reoxygenation (OGD/R) model was established in murine hippocampal HT22 neurons and BV2 microglial cells to simulate ischemic conditions. hAECs-Exos were successfully isolated and characterized via transmission electron microscopy, nanoparticle tracking analysis, and Western blotting. Confocal microscopy confirmed efficient exosome uptake by both cell types. Functional analyses revealed that hAECs-Exos significantly improved cell viability, suppressed pro-inflammatory cytokine release, alleviated oxidative stress, and modulated apoptosis-related proteins. RNA sequencing identified Forkhead box protein M1 (FoxM1) as a significantly upregulated transcription factor following hAECs-Exos treatment. Further experiments demonstrated that knockdown of FoxM1 in hAECs abolished the beneficial effects of exosomes on the viability of HT22 and BV2 cells and on the suppression of inflammation, oxidative stress, and apoptosis. These findings indicate that hAECs-Exos confer neuroprotection through FoxM1-dependent mechanisms. Together, our results highlight the therapeutic potential of hAECs-Exos as a safe, effective, and clinically translatable strategy for ischemic stroke treatment, warranting future validation in vivo and rescue experiments to fully elucidate FoxM1’s causal role. Full article

As one of the key vectors for the transmission of Dengue fever, Aedes albopictus is highly ecologically adaptable. The development of environmentally compatible biological defence and control technologies has therefore become an urgent need for vector biological control worldwide. This study constructed and used double-stranded RNA (dsRNA) expression vectors targeting the cyp314a1 and cyp315a1 genes of Ae. albopictus to transform Chlamydomonas reinhardtii and Chlorella vulgaris, achieving RNA interference (RNAi)-mediated gene silencing. The efficacy of the RNAi recombinant algal strain biocide against Ae. albopictus was evaluated by administering it to Ae. albopictus larvae. The results showed that the oral administration of the cyp314a1 and cyp315a1 RNAi recombinant C. reinhardtii/C. vulgaris strains was lethal to Ae. albopictus larvae and severely affected their pupation and emergence. The recombinant algal strains triggered a burst of ROS (Reactive Oxygen Species) in the mosquitoes’ bodies, resulting in significant increases in the activities of the superoxide dismutase (SOD), peroxiredoxin (POD) and catalase (CAT), as well as significant upregulation of the mRNA levels of the CME pathway genes in larvae. In the simulated field experiment, the number of Ae. albopictus was reduced from 1000 to 0 in 16 weeks by the RNAi recombinant Chlorella, which effectively controlled the population of mosquitoes. Meanwhile, the levels of nitrogen (N), phosphorus (P), nitrate, nitrite, ammonia and COD (Chemical Oxygen Demand) in the test water decreased significantly. High-throughput sequencing analyses of 18S rDNA and 16S rDNA showed that, with the release of RNAi recombinant Chlorella into the test water, the biotic community restructuring dominated by resource competition caused by algal bloom, as well as the proliferation of anaerobic bacteria and the decline of aerobic bacteria triggered by anaerobic conditions, are the main trends in the changes in the test water. This study is an important addition to the use of RNAi recombinant microalgae as a biocide. Full article

In this study, we investigate a shielded capacitive power transfer (S-CPT) system that employs cast iron road covers as transmission electrodes for both dynamic and static charging of electric vehicles. Coupling capacitance was evaluated from S-parameters using copper, aluminum, ductile cast iron, structural steel, and carbon steel electrodes, with additional comparisons of ductile iron surface conditions (casting, machining, electrocoating). In a four-plate S-CPT system operating at 13.56 MHz, capacitance decreased with electrode spacing, yet ductile cast iron reached ~70 pF at 2 mm, demonstrating a performance comparable to that of copper and aluminum despite having higher resistivity and permeability. Power transmission experiments using a Ø330 mm cast iron cover meeting road load standards achieved 58% efficiency at 100 W, maintained around 40% efficiency at power levels above 200 W, and retained 45% efficiency under 200 mm lateral displacement, confirming robust dynamic performance. Simulations showed that shield electrodes enhance grounding, stabilize potential, and reduce return-path impedance. Finite element analysis confirmed that the ductile cast iron electrodes can withstand a 25-ton design load. The proposed S-CPT concept integrates an existing cast iron infrastructure with thin aluminum receiving plates, enabling high efficiency, mechanical durability, EMI mitigation, and reduced installation costs, offering a cost-effective approach to urban wireless charging. Full article

As a pivotal component of the single-gear reducer, the casing of the miniature car reducer not only safeguards the internal transmission system but also interfaces seamlessly with the external structure. Currently, the structural design of domestic single-stage reducers primarily leans on experience and standardized specifications. To guarantee the reliable and stable operation of the casing, a high safety factor is often incorporated, which inevitably results in increased weight and necessitates secure bolting connections. This study presents an innovative scheme to design the flange with the box and realize the lightweight nature of the box by finite element analysis to reduce the manufacturing cost. Based on the working state of maximum torque and maximum speed, this study obtains the stress distribution of each bearing seat under different working conditions and carries out static and dynamic analysis combined with other coupling constraints. The analysis results show that the structure has high stiffness and strength, which is suitable for lightweight design, and that the first ten spontaneous vibration frequencies are far away from the excitation frequency of the inner and outer boundary, avoiding the resonance phenomenon. Moreover, this study proposes a new structure design method, which effectively improves the stiffness of the structure. Through the calculation of volume ratio before and after three optimizations, the optimal volume ratio of 30% is selected, unnecessary materials around the bearing seat are removed, and the layout of ribs is determined. After structural optimization, the weight of the shell is reduced by 10.2%, and both the static and dynamic characteristics meet the design requirements. Full article

Efficient simplification of 3D models is essential for mobile and other resource-constrained application scenarios. Industrial 3D assemblies, typically composed of numerous components and dense triangular meshes, often pose significant challenges in rendering and transmission due to their large scale and high complexity. The Quadric Error Metrics (QEM) algorithm offers a practical balance between simplification accuracy and computational efficiency. However, its application to large-scale industrial models remain limited by performance bottlenecks, especially when combined with curvature-based optimization techniques that improve fidelity at the cost of increased computation. Therefore, this paper presents a parallel implementation of the QEM algorithm and its curvature-optimized variant using the OpenMP framework. By identifying key bottlenecks in the serial workflow, this research parallelizes critical processes such as curvature estimation, error metric computation, and data structure manipulation. Experiments on large industrial assembly models at a simplification ratio of 0.3, 0.5, and 0.7 demonstrate that the proposed parallel algorithms achieve significant speedups, with a maximum observed speedup of 5.5×, while maintaining geometric quality and topological consistency. The proposed approach significantly improves model processing efficiency, particularly for medium- to large-scale industrial models, and provides a scalable and practical solution for real-time loading and interaction in engineering applications. Full article

Autosomal-dominant sleep-related hypermotor epilepsy (ADSHE) was the first distinct genetic epilepsy proven to be caused by mutation of the CHRNA4 gene, originally reported in 1994. In the past three decades, pathomechanisms of ADSHE associated with mutant nicotinic acetylcholine receptors (nAChRs) have been explored via various studies, including in vitro experiments and genetic rodent models. However, findings emphasize that functional abnormalities of ADSHE-mutant nAChRs alone cannot generate ictogenesis; rather, development of abnormalities in various other transmission systems induced by ADSHE-mutant nAChRs during the neurodevelopmental process before the ADSHE onset is involved in development of epileptogenesis/ictogenesis. Intra-thalamic GABAergic disinhibition induced by loss-of-function of S284L-mutant nAChRs (S286L-mutant nAChRs in rat ADSHE models) contributes to enhancing propagation of physiological ripple-burst high-frequency oscillation (HFO) and Erk signaling during sleep, leading to enhancement of the trafficking of pannexin1, connexin43, and P2X7 purinergic receptor to the astroglial plasma membrane. The combination of activation of physiological ripple-HFO and upregulation of astroglial hemichannels under the GABAergic disinhibition plays an important role in generation of epileptogenic fast-ripple-HFO during sleep. Therefore, loss-of-function of the S284L-mutation alone cannot drive ictogenesis but contributes to the development of epileptogenesis as an initial abnormality. Based on these recent findings using genetic rat ADSHE models, harboring the rat S286L-mutant Chrna4 corresponding to the human S284L-mutant CHRNA4, this report proposes hypothetical pathomechanisms of ADSHE. Full article

The rise of social media platforms has fundamentally reshaped the global information ecosystem, fostering the spread of disinformation. Beyond the circulation of false content, this article frames disinformation as an aesthetic crisis of public communication: an algorithmic reorganization of sensory experience that privileges performative virality over shared intelligibility, fragmenting public discourse and undermining democratic deliberation. Drawing on John Dewey’s philosophy of aesthetic experience and critical theory (Adorno, Benjamin, Fuchs, Han), we argue that journalism, understood as a form of public art rather than mere fact-transmission, can counteract this crisis by cultivating critical attention, narrative depth, and democratic engagement. We introduce the concept of aesthetic literacy as an extension of media literacy, equipping citizens to discern between seductive but superficial forms and genuinely transformative experiences. Empirical examples from Portugal (Expresso, Público, Mensagem de Lisboa) illustrate how multimodal journalism—through paced narratives, interactivity, and community dialogue—can reconstruct Deweyan “integrated experience” and resist algorithmic disinformation. We propose three axes of intervention: (1) public education oriented to aesthetic sensibility; (2) journalistic practices prioritizing ambiguity and depth; and (3) algorithmic transparency. Defending journalism as a public art of experience is thus crucial for democratic regeneration in the era of sensory capitalism, offering a framework to address the structural inequalities embedded in global information flows. Full article

To address the issues of small-target missed detection, false alarms from cloud/fog interference, and low computational efficiency in traditional wildfire detection for transmission line corridors, this paper proposes a YOLOv11_MDS detection model by integrating Multi-Scale Convolutional Attention (MSCA) and Distribution-Shifted Convolution (DSConv). The MSCA module is embedded in the backbone and neck to enhance multi-scale dynamic feature extraction of flame and smoke through collaborative depth strip convolution and channel attention. The DSConv with a quantized dynamic shift mechanism is introduced to significantly reduce computational complexity while maintaining detection accuracy. The improved model, as shown in experiments, achieves an mAP@0.5 of 88.21%, which is 2.93 percentage points higher than the original YOLOv11. It also demonstrates a 3.33% increase in recall and a frame rate of 242 FPS, with notable improvements in detecting small targets (pixel occupancy < 1%). Generalization tests demonstrate mAP improvements of 0.4% and 0.7% on benchmark datasets, effectively resolving false/missed detection in complex backgrounds. This study provides an engineering solution for real-time wildfire monitoring in transmission lines with balanced accuracy and efficiency. Full article

In coastal hot and humid regions, the steel pin of AC porcelain insulators often suffers from severe electrochemical corrosion due to surface contamination and moisture, leading to insulator string breakage. Contrary to the common belief that AC corrosion is negligible, this study reveals the significant role of the DC component in leakage currents and the synergy of this DC component with localized high current densities in accelerating corrosion, based on field investigations and experiments. Using a simulation model based on the Suwarno equivalent circuit, it is shown that non-linear contamination causes highly non-sinusoidal leakage currents, with total harmonic distortion up to 40% and a DC component of approximately 22%. To mitigate this, a conductive silicone rubber coating is proposed to block moisture and distribute leakage current evenly, keeping surface current density below the critical threshold of 100 A/m². Simulations indicate that a 2 mm thick coating with conductivity around 10⁻⁴ S/m effectively reduces current density to a safe level. Accelerated corrosion tests confirm that this conductive coating significantly suppresses pitting corrosion caused by high current densities, outperforming traditional insulating coatings. This study presents a practical and effective approach for protecting AC insulators in harsh environments, contributing to improved transmission line reliability in high-temperature and high-humidity regions. Full article

In this study, the use of spent coffee waste as a green precursor of polyphenolic compounds, which are subsequently employed as reducing agents for the synthesis of zero-valent iron nanoparticles (nZVI) aimed at the efficient removal of dyes from aqueous systems, has been investigated. The nanoparticles, generated in situ in the presence of controlled amounts of hydrogen peroxide, were applied in the removal of organic dyes—including methylene blue, methyl orange, and orange G—through a heterogeneous Fenton-like catalytic process. The synthesized nZVI were thoroughly characterized by nitrogen adsorption at 77 K, scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier-transform infrared spectroscopy (FT-IR), and powder X-ray diffraction (XRD). A statistical design of experiments and response surface methodology were employed to evaluate the effect of polyphenol, Fe(III), and H₂O₂ concentrations on dye removal efficiency. Results showed that under optimized conditions, a 100% removal efficiency could be achieved. This work highlights the potential of nZVI synthesized from agro-industrial waste through sustainable routes as an effective solution for water remediation, contributing to circular economy strategies and environmental protection. Full article

The equilibrium between electricity demand and consumption is vital to ensure the stability of the transmission and distribution systems grid (TS & DS) and to ensure the stable operation of the electrical system. The aim of this review study is to highlight the current legislative and technical situation and the possibilities for managing peak loads, decentralization, sharing, storage, and sale of electricity generated from renewable sources in Slovakia. The European Union′s (EU) goal of achieving carbon neutrality by 2050 and a minimum of 42.5% renewable energy consumption by 2030 brings with it obligations for individual member states. These are transposed into national strategies. The current share of renewable sources in Slovakia is approximately 24% and the EU target by 2030 is probably unrealistic. Water resources are practically exhausted; other possibilities for increasing the share of renewable energy sources (RES) are in photovoltaics, wind, and thermal sources. Due to long-term geographical and historical development, electricity production in Slovakia is based on large-scale solutions. The move towards decentralization requires legislative and technical support. The review article examines the possibilities of increasing the share of RES and energy sharing in Slovakia, and examines the legislative, economic, and social barriers to their wider application. At the same time as the share of renewable sources in electricity generation increases, the article examines and presents solutions capable of ensuring the stability of electricity networks across Europe. The study formulates diversified strategies at the distribution network level and the consumer and building levels, and identifies physical (various types of electricity storage, electromobility, electricity liquidators) and virtual (electricity sharing, energy communities, virtual batteries) solutions. In conclusion, it defines the necessary changes in the legislative, technical, social, and economic areas for the most optimal improvement of the situation in the area of increasing the share of RES, supporting the decentralization of the electric power industry, and sharing electricity in Slovakia, also based on experience and good examples from abroad. Full article

In this paper, a broadband photoconductive antenna (PCA) with enhanced full-band radiation power is proposed based on dual-frequency complementary technology. In the proposed PCA, dual-frequency metallic bar resonators are combined with the coplanar transmission line. Dual-frequency resonant cascades in the meta-atomic electrodes enable effective manipulation of the dissipated terahertz energy along the coplanar lines of PCAs and efficient scattering of terahertz energy into the far field, thereby enhancing far-field radiation power. To validate the proposed antenna, the prototype of the proposed PCA is manufactured and measured. Compared with the conventional PCA, experimental results indicate that our PCA increases the THz radiation power of the entire radiation frequency band (0.02–1.5 THz) by 4.5 times. In addition, our experiments demonstrate that the proposed PCA overcomes the narrowband resonant response characteristics of traditional methods, significantly improving energy utilization efficiency. This design offers a reproducible and universal approach to effectively harness this dissipated terahertz energy, opening a path to rapidly advancing the practicality of terahertz techniques. Full article

High-energy (710 MeV) Bi ion track morphology in polycrystalline silicon nitride was investigated during post-irradiation annealing. Using both in-situ and ex-situ transmission electron microscopy, we monitored the recovery of crystallinity within initially amorphous ion track regions. In-situ annealing involved heating samples from room temperature to 1000 °C in 50 °C increments, each held for 10 s. We observed a steady decrease in both the size and number of tracks, with only a small number of residual crystalline defects remaining at 1000 °C. Ex-situ annealing experiments were conducted at 400 °C, 700 °C, and 1000 °C for durations of 10, 20, and 30 min. Complete restoration of the crystalline lattice occurred after 30 min at 700 °C and 20 min at 1000 °C. Due to inherent differences in geometry, heat flow, and stress conditions between thin lamella and bulk specimens, in-situ and ex-situ results cannot be compared. Molecular dynamics simulations further revealed that track shrinkage begins in cells within picoseconds, supporting the notion that recrystallization can start on very short timescales. Overall, these findings demonstrate that thermal recrystallization of damage induced by swift heavy ion irradiation in polycrystalline Si₃N₄ is possible. This study provides a foundation for future research aimed at better understanding radiation damage recovery in this material. Full article