Search Results (42)

Germanium (Ge) incorporation profoundly modifies the structural and electronic characteristics of carbon fullerenes, giving rise to a diverse landscape of substitutional, exohedral, and endohedral Ge–fullerene architectures. Although experimental studies demonstrate that Ge can be introduced into fullerene matrices through nuclear recoil implantation and arc-discharge synthesis, only exohedral germylated derivatives have been structurally confirmed to date. Substitutional germanium-doped fullerene (Ge-C₆₀) species remain experimentally elusive, with available evidence relying largely on radiochemical signatures and indirect spectroscopic data. In contrast, computational investigations provide a detailed and coherent picture of germanium doping across fullerene sizes, showing that Ge induces significant cage distortion, breaks local symmetry, narrows the highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) gap, and enhances charge localization at the dopant site. These electronic perturbations strongly increase the affinity of Ge-doped fullerenes for external guest molecules, leading to enhanced adsorption energies and distinct optical and transport responses in exohedral complexes. Theoretical studies of endohedral systems further indicate that Ge atoms or small clusters could form stable encapsulated species with unique electronic properties. Collectively, current evidence positions germanium-doped fullerenes as electronically versatile nanostructures with potential applications in sensing, optoelectronics, catalysis, and nanomedicine, while highlighting the need for definitive experimental synthesis and structural validation of substitutional Ge-fullerene derivatives. Full article

The large-scale integration of renewable energy has reduced power system flexibility and exacerbated supply–demand imbalances. In industrial parks, the combined variability of high energy-consuming industrial loads and photovoltaic (PV) generation further complicates the energy management challenge. Aiming to enhance the operational flexibility of industrial parks and mitigate supply–demand imbalances, this paper proposes a multi-time-scale stochastic energy management strategy that accounts for the uncertainty associated with PV generation. First, a conditional generative adversarial network (CGAN) is employed to generate the representative PV generation scenarios, thereby enabling the modeling of PV generation uncertainty within the optimal dispatch model. Considering the coupling mechanisms and control characteristics of various regulation resources within the industrial park, a multi-time-scale dispatch model is developed. In the day-ahead dispatch phase, the operational costs are minimized by optimizing the production plans of industrial loads. In contrast, in the intraday phase, the more flexible measures, such as adjusting the tap positions of arc furnaces and controlling the charge/discharge of energy storage systems, are employed to smooth power fluctuations within the park. A case study validated the effectiveness of the proposed approach, demonstrating a 7.56% reduction in power fluctuations and a 4.34% decrease in daily operating costs. These results highlight the significance of leveraging industrial loads in park-level systems to enhance cost efficiency and renewable energy integration. Full article

Emerging contaminants such as per- and polyfluoroalkyl substances (PFASs) pose significant challenges for conventional wastewater treatment technologies. Non-thermal plasma (NTP) has gained attention as a promising advanced oxidation process capable of degrading persistent pollutants via hydrated electrons and reactive oxygen/nitrogen species under ambient conditions. This review summarizes recent progress in the application and scale-up of NTP for water treatment, with a focus on reactor configurations, degradation mechanisms, and energy efficiency. Key plasma reactor types—including dielectric barrier discharge, corona discharge, plasma jets, and gliding arc discharge—are evaluated for their suitability in large-scale applications. Pilot-scale studies addressing pharmaceuticals, dyes, and PFASs are reviewed to assess scalability, cost, and operational viability. Although NTP systems consistently achieve >80% contaminant removal, optimizing energy use and maintaining performance across complex water matrices remain critical challenges. Hybrid systems integrating NTP with ozonation, ultrafiltration, or cavitation show potential to improve treatment efficacy and reduce energy demands. Future research priorities include reactor design optimization, contaminant-specific plasma tuning, and technoeconomic analysis to support the translation of NTP technologies from lab-scale innovation to field-scale implementation. Full article

The large-scale utilization of hydrogen energy is currently hindered by challenges in low-cost production, storage, and transportation. This study focused on investigating the impact of the diaphragm cavity profile on the movement behavior and stress distribution of a dual-stage diaphragm compressor. Firstly, an experimental platform was established to test the gas mass flowrate and fluid pressures under various preset conditions. Secondly, a simulation path integrating the finite element method simulation, theoretical stress model, and movement model was developed and experimentally validated to analyze the diaphragm stress distribution and deformation characteristics. Finally, comparative optimization analyses were conducted on different types of diaphragm cavity profiles. The results indicated that the driving pressure differences at the top dead center position reached 85.58 kPa for the first-stage diaphragm and 75.49 kPa for the second-stage diaphragm. Under experimental conditions of 1.6 MPa suction pressure, 8 MPa second-stage discharge pressure, and 200 rpm rotational speed, the first-stage and second-stage diaphragms reached the maximum center deflections of 4.14 mm and 2.53 mm, respectively, at the bottom dead center position. Moreover, the cavity profile optimization analysis indicated that the double-arc profile (DAP) achieved better cavity volume and diaphragm stress characteristics. The first-stage diaphragm within the optimized DAP-type cavity exhibited 173.95 MPa maximum principal stress with a swept volume of 0.001129 m³, whereas the second-stage optimized configuration reached 172.57 MPa stress with a swept volume of 0.0003835 m³. This research offers valuable insights for enhancing the reliability and performance of diaphragm compressors. Full article

Thermal runaway in microwave hybrid heating of ceramics is an unwanted phenomenon which damages the sintered products. The aim of the present study is to establish to what extent the pressing forces of 100, 200 and 300 MPa used in the compaction process and the optimization of the microwave heating mechanism can reduce the occurrence of thermal runaway. Modeling and simulation of temperature distributions alongside defects created by the compaction process are performed in order to evaluate their influence on the stability of MHH. Based on CT scanning, defects with dimensions from 110 to 515 μm are studied in terms of local overheating and how the thermal runaway can lead to internal arc discharge. The results show that samples compacted at 100 MPa and exposed at 600 W injected power reach temperatures peaks around 1010 °C and are affected by major cracks and large melted areas. The samples compacted at 200 and 300 MPa present similar behavior, without arc discharge, but are also affected by cracks. Based on these findings, the MHH process can be applied to sintering processes but with a reduced injected power below 300 W for samples compacted with pressing forces higher than 300 MPa. Full article

Plastic waste (PW) presents a significant environmental challenge due to its persistent accumulation and harmful effects on ecosystems. According to the United Nations Environment Program (UNEP), global plastic production in 2024 is estimated to reach approximately 500 million tons. Without effective intervention, most of this plastic is expected to become waste, potentially resulting in billions of tons of accumulated PW by 2060. This study explores innovative approaches to convert PW into high-value carbon nanomaterials (CNMs) such as graphene, carbon nanotubes (CNTs), and other advanced carbon structures. Various methods including pyrolysis, arc discharge, catalytic degradation, and laser ablation have been investigated in transforming PW into CNMs. However, four primary methodologies are discussed herein: thermal decomposition, chemical vapor deposition (CVD), flash joule heating (FJH), and stepwise conversion. The scalability of the pathways discussed for industrial applications varies significantly. Thermal decomposition, particularly pyrolysis, is highly scalable due to its straightforward setup and cost-effective operation, making it suitable for large-scale waste processing plants. It also produces fuel byproducts that can be used as an alternative energy source, promoting the concept of energy recovery and circular economy. CVD, while producing high-quality carbon materials, is less scalable due to the high cost and required complex equipment, catalyst, high temperature, and pressure, which limits its use to specialized applications. FJH offers rapid synthesis of high-quality graphene using an economically viable technique that can also generate valuable products such as green hydrogen, carbon oligomers, and light hydrocarbons. However, it still requires optimization for industrial throughput. Stepwise conversion, involving multiple stages, can be challenging to scale due to higher operational complexity and cost, but it offers precise control over material properties for niche applications. This research demonstrates the growing potential of upcycling PW into valuable materials that align with global sustainability goals including industry, innovation, and infrastructure (Goal 9), sustainable cities and communities (Goal 11), and responsible consumption and production (Goal 12). The findings underscore the need for enhanced recycling infrastructure and policy frameworks to support the shift toward a circular economy and mitigate the global plastic crisis. Full article

Cu-W alloys are widely used in high-voltage circuit breaker contacts due to their high resistance to arc ablation, but few studies have analyzed the microstructure of Cu-W alloys under arc ablation. This study applied a phase-field model based on the phase-field model developed by Karma and co-workers to the evolution of dendrite growth in the solidification process of Cu-W alloy under arc ablation. The process of columnar dendrite evolution during solidification was simulated, and the effect of the supercooling degree and anisotropic strength on the morphology of the dendrites during solidification was analyzed. The results show that the solid–liquid interface becomes unstable with the release of latent heat, and competitive growth between dendrites occurs with a large amount of solute discharge. In addition, when the supercooling degree is 289 K, the interface is located at a lower height of only 15 μm, and the growth rate is slow. At high anisotropy, the side branches of the dendrites are more fully developed and tertiary dendritic arms appear, leading to a decrease in the alloy’s relative density and poorer ablation resistance. In contrast, the main dendrites are more developed under high supercooling, which improves the density and ablation resistance of the material. The results in this paper may provide a novel way to study the microstructure evolution and material property changes in Cu-W alloys under the high temperature of the arc for high-voltage circuit breaker contacts. Full article

An arc glow discharge device was used to prepare a helical carbon fiber skeleton with helical carbon fibers hooked to each other by spraying a hydrogen and ethanol mixture onto the iron wire substrate through the discharge area, using anhydrous ethanol as the carbon source. The samples were characterized by SEM, EDS, Raman and XPS. A growth mechanism of helical carbon fiber driven by C sp3 was proposed. The various growth modes of carbon fiber during the formation of carbon fiber skeleton were investigated. A ring appearance that indicated a change in the direction of carbon fiber growth was observed. And double helical carbon fiber was constructed from single helical carbon fiber in two ways. Super-large carbon fiber with a diameter of about 13 μm was observed, and it was speculated that this super-large carbon fiber is the backbone of the carbon fiber skeleton. The mechanical properties of the carbon fiber skeleton are isotropic. Full article

Carbon nanotubes, as carbon allotropes distinguished by their intricate structures and exceptional physicochemical properties, have demonstrated substantial progress in recent years across diverse domains, including energy production, chemical synthesis, and environmental preservation. They exhibit notable attributes such as high thermal stability, superior adsorption capacity, and a substantial specific surface area, rendering them superb catalyst supports. Particularly in electrochemical energy storage, CNTs are extensively employed in supercapacitor electrodes owing to their elevated electrical conductivity, mechanical robustness, and electrocatalytic prowess, which facilitate significant energy storage capabilities. Their intricate pore architecture and reactive sites make functionalized carbon nanotubes well suited for synthesizing composite materials with diverse components, which are ideal for sequestering carbon dioxide from both atmospheric and indoor environments. This review presents a comprehensive examination of carbon nanotube synthesis methodologies, encompassing chemical vapor deposition, arc discharge, and laser ablation, and evaluates their impacts on the structural and functional properties of carbon nanotubes. Furthermore, this article underscores the applications of carbon nanotubes in fields such as fuel cells, photocatalysis, ammonia synthesis, dry methane reforming, Fischer–Tropsch synthesis, and supercapacitors. Despite the considerable potential of carbon nanotubes, their manufacturing processes remain intricate and costly, impeding large-scale industrial production. This review concludes by addressing the challenges in fabricating carbon nanotube composites and outlining future development prospects. Full article

Plasma treatment of wood surfaces has shown significant effects, but different excitation methods used for different species of wood generally result in varied characteristics of wood surfaces. Secondly, plasma modification greatly enhances the absorption of liquids by wood, but the relationship between liquid absorption and surface wettability is rarely studied. Limited detailed investigation of the modification effects and mechanisms has hindered the large-scale applications of plasma treatment in the wood industry. In this study, two typical plasmas, radio frequency (RF) plasma and gliding arc discharge (GAD) plasma, were employed to treat three species of wood: poplar, black walnut, and sapele. By focusing on changes in the contact angle of the wood surface, an exponential equation fitting method is used to determine the measurement time for contact angles. The research identified that factors contributing to the decrease in contact angle after plasma modification include not only the increase in surface energy but also liquid absorption. SEM and XPS analyses demonstrate that plasma etching accelerated liquid absorption by modifying the surface topography, while the increase in surface energy was due to the addition of oxygen-containing groups. High-valence C=O and O-C=O groups serve as indicators of plasma-induced surface chemical reactions. RF modification primarily features surface etching, whereas GAD significantly increases the active surface groups. Thus, different plasmas, due to their distinct excitation modes, produce diverse modification effects on wood. Considering the various physical and chemical properties of plasma-modified wood surfaces, recommendations for adhesive use on plasma-modified wood are provided. Full article

Ship pollution emissions have attracted increasing attention in the maritime field due to the massive growth of maritime traffic activities. It is important to identify the ship emissions (SEs) magnitude and corresponding spatial and temporal distributions for the purposes of developing appropriate strategies to mitigate environment pollution. The aim of this study was to estimate ship pollution emissions with various typical merchant ship types under different sailing conditions. We estimated the emission variation with a ship traffic emission assessment model (STEAM2), and then the ship pollution emission distribution was further visualized using ArcGIS. We collected data from the automatic identification system (AIS) for ships in New York Harbor and further analyzed the spatiotemporal distribution of pollutant emissions from ships. The experimental results demonstrate that the ship pollutant emission volume in the New York Harbor area in 2022 was 3340 t, while the pollution in terms of CO, SO₂, C_XH_X, PM₁₀, NO_X, and PM_2.5 was 136, 1421, 66, 185, 1384, and 148 t, respectively. The overall SEs from container ships, passenger ships, and tankers account for a large amount of pollution discharge. The pollutant emissions of container ships are significantly greater than that of their counterparts. Moreover, the spatiotemporal distributions of ship pollutant discharge can vary significantly among different ship types and sailing conditions. Full article

With the shortage of fossil fuels and the increasingly serious problem of environmental pollution, low-carbon industrial production technology has become an effective way to reduce industrial carbon emissions. Electrified steel plants based on electronic arc furnaces (EAF) can reduce most carbon emissions compared with traditional steel production methods, but the production steps have fixed electricity consumption behavior, and impact loads are easily generated in the production process, which has an impact on the stability of the power system. EV has the characteristics of a mobile energy storage unit. When a large number of EVs are connected to the power grid, they can be regarded as distributed energy storage units with scheduling flexibility. Through the orderly scheduling of EVs, the spatial–temporal transfer of EV charging and discharging load can be realized. Therefore, the EV situated in the steel plant’s distribution network node has the capacity to be utilized by providing peak shaving and valley filling services for the steel production load. This study proposes an operation optimization scheduling method for EVs and steel plants. Taking the lowest overall operating cost as the objective, an optimal scheduling model considering EVs operation, steel plant, and distributed generator is established. Based on the IEEE-33 node distribution network model considering distributed generators, the proposed model is simulated and analyzed, and the effectiveness of the EV steel plant operation optimization scheduling strategy is investigated. Full article

Sulfur hexafluoride (SF₆) is a typical fluorine gas with excellent insulation and arc extinguishing properties that has been widely used in large-scale power equipment. The detection of SF₆ gas in high-power electrical equipment is a necessary measure to ensure the reliability and safety of power grid operation. A failure of SF₆ insulated electrical equipment, such as discharging or overheating conditions, can cause SF₆ gas decomposition, resulting in various decomposition products. The decomposed gases inside the equipment decrease the insulating properties and are toxic. The leakage of SF₆ can also decrease the insulating properties. Therefore, it is crucial to monitor the leakage of SF₆ decomposed gases from electrical equipment. Quantitative testing of decomposition products allows us to assess the insulation state of the equipment, identify internal faults, and maintain the equipment. This review comprehensively introduces the decomposition formation mechanism of SF₆ gas and the current detection technology of decomposition products from the aspects of principle and structure, materials, test effect, and practicability. Finally, the development trends of SF₆ and decomposition gas detection technology for the reliability and safety of power grid operation are prospected. Full article

Tri-metallofullerenes, specifically ${\mathrm{M}}_3@{\mathrm{C}}_{80}$ where M denotes rare-earth metal elements, are molecules that possess intriguing magnetic properties. Typically, only one metal element is involved in a given tri-metallofullerene molecule. However, mixed tri-metallofullerenes, denoted as M1_xM2_3-x@C₈₀ (x = 1 or 2, M1 and M2 denote different metal elements), have not been previously discovered. The investigation of such mixed tri-metallofullerenes is of interest due to the potential introduction of distinct properties resulting from the interaction between different metal atoms. This paper presents the preparation and theoretical analysis of mixed rare-earth tri-metallofullerenes, specifically Y_xDy_3−x@C₈₀ (x = 1 or 2). Through chemical oxidation of the arc-discharge produced soot, the formation of tri-metallofullerene cations, namely ${\mathrm{Y}}_2\mathrm{D}\mathrm{y}@{\mathrm{C}}_{80}^{+}$ and ${\mathrm{Y}\mathrm{D}\mathrm{y}}_2@{\mathrm{C}}_{80}^{+}$, has been observed. Density functional theory (DFT) calculations have revealed that the tri-metallofullerenes Y_xDy_3−x@C₈₀ (x = 1 or 2) exhibit a low oxidation potential, significantly lower than other fullerenes such as C₆₀ and C₇₀. This low oxidation potential can be attributed to the relatively high energy level of a singly occupied orbital. Additionally, the oxidized species demonstrate a large HOMO-LUMO gap similar to that of Y_xDy_3−xN@C₈₀, underscoring their high chemical stability. Theoretical investigations have uncovered the presence of a three-center two-electron metal–metal bond at the center of ${\mathrm{Y}}_2\mathrm{D}\mathrm{Y}@{\mathrm{C}}_{80}^{+}$ and ${\mathrm{Y}\mathrm{D}\mathrm{y}}_2@{\mathrm{C}}_{80}^{+}$. This unique multi-center bond assists in alleviating the electrostatic repulsion between the metal ions, thereby contributing to the overall stability of the cations. These mixed rare-earth tri-metallofullerenes hold promise as potential candidates for single-molecule magnets. Full article

Flood analyses when using a GIS-based integrated approach have been successfully applied around the world in large-sized watersheds. This study employed hydrological-hydraulic modeling to analyze flash floods by integrating HEC-HMS, HEC-RAS, and ArcGIS software for flood evaluation and control in a micro-watershed in the Samaru River, Nigeria. The watershed boundaries, its characteristics (soil and land use), the topographical survey, and the intensity duration frequency curve (IDF) of the study area were produced using data-driven techniques. The HEC-HMS model was used to derive the peak discharges for 2-, 5-, 10-, 25-, 50-, 100-, and 200-year return periods with the frequency storm method. Afterward, the water surface profiles for the respective return periods were estimated using the HEC-RAS hydrodynamic model. The simulated design flood for the 2-, 5-, 10-, 25-, 50-, 100-, and 200-year return periods at the reference location (the NUGA gate culvert) were 3.5, 6.8, 9.1, 12.1, 14.3, 16.6, and 19.0 m³/s, respectively, while those at the watershed outlet for the respective return periods were 7.5, 14.9, 20.3, 27.3, 32.6, 38.0, and 43.5 m³/s, respectively (with a water height of 0.9 m, 1.1 m, 1.3 m, 1.33 m, 1.38 m, 1.5 3m, and 1.8 m, respectively), at the NUGA gate culvert cross-section. The maximum water depths of about 0.9 m and 1.0 m were recorded in the right and left overbanks, which were similar to the simulated water depth for the 2- and 5-year return periods. Hence, for the smart control of floods passing through the river and major hydraulic structures, a minimum design height of 1.50 m is recommended. For the most economic trapezoidal channel section, a normal depth of 1.50 m, a bottom width of 1.73 m, a top width of 3.50 m, and a free board of 0.30 m is proposed to curb the overtopping of floods along the channel sub-sections. The findings of this study could help hydraulic engineers minimize flooding in streams and rivers overbanks in a micro-watershed. Full article