Search Results (319)

Public health suffers from noxious gas emitted by massive beached Sargassum algae. Net-barrages deployed in near-shore seas can contain Sargassum, provided they efficiently resist the additional hydrodynamic pressure induced by the catch. Nowadays, the design and installation of net-barrages are empiric. Structural breaks and anchor and mooring chain drifts can arise. We provide a mechanical model to evaluate stresses and loads on a structure made of fishing nets and buoy moorings. Hydrodynamic uncertainties occur through catches, fouling and sea current amplitudes appearing in lagoons or sheltered bays. This study presents a non-linear four-node finite-element model for continuous elastic membranes undergoing large displacements and small strains. The model relies on the Lagrangian linearly elastic membrane theory, employing the non-linear Green strain tensor and a non-updated hydrodynamic loading. We study forcings fixed a priori on a netting section of barrage that is 50 m long and 1 m high with double layer, e.g., two net-faces. We consider low and moderate current velocities, 0.05 and 0.35 m∙s⁻¹, while assuming specific vertical and horizontal catch pressures. A barrage installed in the reef lagoon at Le François on Martinique Island that is observable by satellite imagery could benefit of the computed net and mooring tensions. Full article

Non-insulated heat exchangers in gas-to-gas service lose substantial energy to the surroundings. This study evaluates Al₂O₃ and ZnO ceramic coatings (200 $\mathsf{\mu }$m) as passive thermal retention layers on the inner surface of the outer tube in a copper double-pipe heat exchanger, using 3D CFD simulations verified for internal consistency against Log Mean Heat Transfer Rate analytical solutions. Six cases were modelled: three coating conditions across parallel-flow and counter-flow configurations under laminar conditions ($R{e}_i\approx 525$, $R{e}_o\approx 192$) with air as the working fluid. The coating elevates the outer tube inner wall temperature $T_3$, increasing the convective driving force to the cold fluid while suppressing ambient dissipation. In parallel flow, Al₂O₃ increases the net inter-fluid heat transfer rate by 35.7% and reduces ambient losses by 81.4%; ZnO achieves 30.9% and 70.4%, respectively. In counter-flow, Al₂O₃ yields a 26.6% enhancement and 73.2% loss reduction. The coated parallel-flow configuration outperforms the uncoated counter-flow baseline. Thermal circuit analysis shows that Al₂O₃ superiority arises from its higher conductivity (40 vs. 19 W m⁻¹ K⁻¹), which sustains a higher equilibrium $T_3$ and a heat partition ratio of 11.84 versus 7.17 for ZnO. These results show that a single ceramic coating layer can recover a large fraction of the thermal energy lost through non-insulated walls, offering a low-cost, retrofit-compatible pathway to improve the energy efficiency of gas-to-gas heat exchangers in HVAC, building energy recovery, and industrial process heat applications. Full article

The global energy transition and the implementation of carbon capture, utilization, and storage (CCUS) strategies require energy-efficient and scalable CO₂ separation technologies. Mixed-matrix membranes (MMMs), combining polymer matrices with functional inorganic or hybrid nanofillers, have emerged as advanced separation platforms capable of surpassing the conventional permeability–selectivity trade-off observed in neat polymer membranes. This review critically evaluates recent developments in modern hybrid membranes for CO₂ separation from synthetic and industrial gas mixtures, including CO₂/N₂ (flue gas), CO₂/CH₄ (natural gas and biogas upgrading), and syngas systems. Particular emphasis is placed on MMMs incorporating covalent organic frameworks (COFs), metal–organic frameworks (MOFs), graphene oxide (GO), MXenes, transition metal dichalcogenides (TMDs), carbon nanotubes (CNTs), g-C₃N₄, layered double hydroxides (LDH), zeolites, metal oxides, and magnetic nanoparticles. Reported performance ranges include CO₂ permeability (P_CO2) typically between 100 and 800 Barrer, CO₂/N₂ selectivity up to 319, and CO₂/CH₄ selectivity up to 249, depending on filler chemistry, loading, and interfacial compatibility. The mechanisms governing gas transport—molecular sieving, selective adsorption, facilitated transport, and diffusion-pathway engineering—are systematically discussed. Key challenges addressed include filler dispersion, polymer–filler interfacial defects, physical aging, moisture sensitivity, oxidation (particularly in MXenes), and scalability toward industrial membrane modules. Future perspectives focus on sub-nanometer pore engineering, surface functionalization to enhance CO₂ affinity, controlled alignment of 2D nanosheets to promote directional transport, multifunctional core–shell and hollow structures, and the integration of computational modeling and machine learning for accelerated material design. Modern hybrid MMMs are identified as strategically important materials enabling high-efficiency CO₂ separation processes aligned with decarbonization and energy transition objectives. Full article

The low separation efficiency of alkali/surfactant/polymer (ASP)-flooding-produced water, attributed to its high emulsification, high viscosity, and surfactant enrichment, presents a significant treatment challenge. To evaluate the effects of flotation unit structure on internal flow field characteristics and the separation performance of oil and suspended solids in a dissolved air flotation–sedimentation tank, this study conducted CFD numerical simulations. The results demonstrate that with 40 gas injection ports, the flow field achieves optimal uniformity and stability: the oil removal rate reaches 68.1%, and the suspended solids removal rate reaches 56.6%. Compared to the single-ring and triple-ring configurations, the double-ring gas injection form exhibits better flow continuity, resulting in increased removal rates of 67.6% for oil and 56.7% for suspended solids. At a gas injection ring height of 10,500 mm, the oil layer in the flotation zone remains continuous and stable, while suspended solids settle into a distinct sediment layer at the bottom, enhancing both oil and suspended solids removal efficiencies. On this basis, the optimized structure of the flotation unit was determined. The removal rates of oil and suspended solids were enhanced by approximately 1.8% to 4.8% and 3.5% to 7.0%, respectively, compared to the existing conditions. Full article

A corrosion device was established to simulate the service environment of stainless steel heat exchanger tubes in a gas water heater. The pitting corrosion behaviors on the inner walls of 444, 445 and 316L stainless steel tubes were investigated in a tap water solution at 60 °C under different heating temperatures from 600 to 800 °C for 500 h by means of optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses. The increase in heating temperature significantly promotes the thickening of scale layers and the formation and growth of corrosion pits on the inner surfaces of the three stainless steel tubes. Under different heating temperature conditions, the maximum and average depths of corrosion pits decrease sequentially from 444 to 445 and then to 316L stainless steel. The scales have similar compositions for the three steel tubes, but the scale thickness is thinner on 316L stainless steel than on the other two steels. In addition, the double-loop electrochemical potentiokinetic reactivation (DL-EPR) test indicates that there is almost no sensitization for the outer walls of the three stainless steel tubes after being heated at 800 °C. 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

Electric vehicles (EVs) represent a key pathway toward reducing greenhouse gas emissions and fossil fuel dependence. Although significant advances have been achieved in energy storage technologies for EVs, a structured comparative assessment that jointly evaluates batteries, supercapacitors, and their hybridisation remains lacking. This review addresses that gap by systematically comparing lithium-ion, lead-acid, and nickel-based batteries with electrochemical double-layer capacitors (EDLCs), pseudocapacitors, and hybrid capacitors across ten performance and sustainability criteria. A literature-informed scoring framework, supplemented by sensitivity analysis under alternative weighting scenarios, is employed to rank the technologies. Particular attention is given to Hybrid Energy Storage Systems (HESS), which combine the high energy density of lithium-ion batteries with the high power density and long cycle life of supercapacitors. The review synthesises evidence that HESS can improve overall energy efficiency by up to 20% and extend battery lifetime by 30–50%, thereby reducing raw-material extraction, electronic waste, and lifecycle cost. Second-life pathways and circular-economy implications are discussed in depth. The findings demonstrate that neither batteries nor supercapacitors alone can satisfy the full spectrum of EV energy demands; instead, their integration within HESS offers the most balanced, sustainable, and economically viable solution. This work provides actionable insights for engineers, policymakers, and stakeholders engaged in next-generation sustainable mobility. Full article

The main aim of this study was to evaluate the applicability of a low-cost, double-wall gas metal arc welding (GMAW)-based wire arc additive manufacturing (WAAM) process for aluminum alloy AlMg5, with an emphasis on microstructural heterogeneity, layer-dependent defect formation, and their implications for mechanical performance and geometric characteristics. A Taguchi L9 (3³) design of experiments was employed to investigate the influence of welding current (40–60 A), shielding gas flow (10–20 L/min), and arc correction (0–40%) on wall geometry, material utilization, and overall process quality through multi-response optimization. The optimal parameter set (60 A, 15 L/min, 0% arc correction) resulted in a 54.9% improvement in the Grey Relational Grade compared to the lowest-performing configuration. Metallographic analysis revealed heterogeneous grain evolution governed by the multilayer thermal history, with porosity levels ranging from 3.20% to 3.49% and lack-of-fusion defects preferentially concentrated in interlayer and mid-height regions. The fabricated high-wall structure exhibited hardness values between 72 and 85 HV and an average ultimate tensile strength of 175 MPa. The observed mechanical scatter was consistent with localized microstructural heterogeneity and spatial defect distribution. The results demonstrate that geometric evaluation alone is insufficient as a quality metric for WAAM components and must be complemented by metallographic integrity assessment. Overall, the study highlights the importance of direct parameter optimization in double-wall WAAM structures to mitigate defect formation and enhance mechanical reliability under industrially accessible deposition conditions. Full article

The development of hybrid organic coatings for corrosion protection remains a key research priority. This study focuses on synthesising Layered Double Hydroxide (ZnGa-LDHs) intercalated with environmentally friendly disodium sebacate (SB) corrosion inhibitor, forming ZnGa-SB. To overcome the challenge of limited dispersibility in organic coatings, ZnGa-SB was combined with Graphene Nanoribbons (GNR), produced through the oxidative unzipping of multi-walled carbon nanotubes (MWCNT). The resulting composite, ZnGa-SB/GNR, was synthesised using an in situ hydrothermal method and incorporated into polyurethane (PU) enamel. The synergy between high-barrier GNRs and active ZnGa-SB creates a “labyrinth effect” that effectively inhibits the diffusion of corrosive species. Microstructural analysis, including XRD, FT-IR, Raman, TGA, FE-SEM, and EDS, confirmed the nanofiller structure. The nanofillers were embedded into acrylic resin (AC) for short-term anticorrosive testing in a 0.1 M NaCl solution and then into PU for long-term evaluation in a 3.5 wt% NaCl solution, using electrochemical impedance spectroscopy (EIS). The PU/ZnGa-SB/GNR coating exhibited a high impedance modulus of 5.90 × 10⁷ Ω cm² at |Z|_0.01 Hz, even after 2688 hours of immersion, indicating enhanced corrosion resistance. This coating demonstrated superior performance in cross-cut and pencil hardness tests and sustained less damage in salt spray analysis compared to other coatings. The synergistic effect offers a promising approach for developing next-generation hybrid anti-corrosive coatings. Full article

Vertical cavity surface emitting lasers (VCSELs) have shown great potential in high-speed communication, quantum information processing, and 3D sensing due to their excellent beam quality and low power consumption. However, generating high-purity and controllable circularly polarized light usually requires external optical components such as quarter-wave plates, which undoubtedly increases system complexity and volume, hindering chip-level integration. To address this issue, we propose a monolithic integration scheme that directly integrates a custom-designed double-layer asymmetric metasurface onto the upper distributed Bragg reflector of a chiral VCSEL. This metasurface consists of a rotated GaAs elliptical nanocolumn array and an anisotropic grating above it. By precisely controlling the relative orientation between the two, the in-plane symmetry of the structure is effectively broken, introducing a significant optical chirality response at a wavelength of 1550 nm. Numerical simulations show that this structure can achieve a near 100% high reflectivity for the left circularly polarized light (LCP), while suppressing the reflectivity of the right circularly polarized light (RCP) to approximately 33%, thereby obtaining an efficient in-cavity circular polarization selection function. Based on this, the proposed VCSEL can directly emit high-purity RCP without any external polarization control components. This compact circularly polarized laser source provides a key solution for achieving the next generation of highly integrated photonic chips and will have a profound impact on frontier fields such as spin optics, secure communication, and chip-level quantum light sources. Full article

Two-dimensional carbide crystals (MXenes) are emerging as a promising platform for the development of novel gas sensors, offering advantages in energy efficiency and tunable analyte selectivity. One of the most effective strategies to enhance and tailor their functional performance involves forming hetero-structured composites with metal oxides. In this work, we explore a chemiresistive effect in double-metal MXene of Ti_0.2V_1.8C and its composites with 2 mol. % SnO₂ and Co₃O₄ nanocrystalline oxides toward feasibility tests with alcohol and ammonia vapor probes. The materials were characterized by simultaneous thermal analysis, X-ray diffraction analysis, Raman spectroscopy, and scanning/transmission electron microscopy. Gas-sensing experiments were carried out on composite layers deposited on multi-electrode substrates to be exposed to the test gases, 200–2000 ppm concentrations, at an operating temperature of 370 °C. The developed sensor array demonstrated clear analyte discrimination. The distinct sensor responses enabled a selective identification of vapors through linear discriminant analysis, demonstrating the further potential of MXene-based materials for integrated electronic nose applications. Full article

This study experimentally evaluates the mechanical and microstructural performance of single- and double-layer intraply hybrid composite (IRC) laminates produced using the hand lay-up method, focusing on Glass–Aramid (GA), Aramid–Carbon (AC), and Carbon–Glass (CG) configurations. Tensile, flexural, compressive, and density tests were conducted in accordance with relevant ASTM standards to assess the influence of hybrid type and layer number under field-representative manufacturing conditions. Microstructural investigations were performed using optical microscopy and scanning electron microscopy (SEM) to identify fabrication-induced imperfections and their relationship to mechanical behavior. The results demonstrate that increasing the laminate configuration from single to double layer significantly enhances mechanical performance across all hybrid types. Double-layer AC laminates exhibited the highest tensile strength (330.4 MPa) and Young’s modulus (11.93 GPa), corresponding to improvements of approximately 85% and 59%, respectively, compared to single-layer counterparts. In flexural loading, the highest strength was observed in double-layer CG laminates (97.14 MPa), while compressive strength was maximized in double-layer AC laminates (34.01 MPa), indicating improved stability and resistance to compression-driven failure. Statistical analysis confirmed that layer number is the dominant parameter governing mechanical response, exceeding the influence of hybrid configuration alone. Microstructural observations revealed fiber misorientation, incomplete resin impregnation, and localized voids inherent to manual fabrication. However, these imperfections were consistently distributed across all specimens and did not obscure comparative mechanical trends. Coefficients of variation generally remained below 10%, indicating acceptable repeatability despite non-ideal manufacturing conditions. Full article

Flexible strain sensors capable of conformal integration with living organisms are essential for advanced wearable electronics, human–machine interaction, and plant health. However, many existing sensors require complex fabrication or rely on non-breathable elastomer substrates that interfere with the physiological microenvironment of skin or plant tissues. Here, we present a low-cost, breathable, and highly stretchable strain sensor constructed from biomedical materials, in which a double-layer medical elastic bandage serves as the porous substrate and an intermediate conductive medical elastic tape impregnated with carbon nanotubes (CNTs) ink acts as the sensing layer. Owing to the hierarchical textile porosity and the deformable CNTs percolation network, the sensor achieves a wide strain range of 100%, a gauge factor of up to 2.72, and excellent nonlinear second-order fitting (R² = 0.997). The bandage substrate provides superior air permeability, allowing long-term attachment without obstructing moisture and gas exchange, which is particularly important for maintaining skin comfort and preventing disturbances to plant epidermal physiology. Demonstrations in human joint-motion monitoring and real-time plant growth detection highlight the device’s versatility and biological compatibility. This work offers a simple, low-cost yet effective alternative to sophisticated strain sensors designed for human monitoring and plant growth monitoring, providing a scalable route toward multifunctional wearable sensing platforms. Full article

This research numerically investigates the cooling performance of Diamond-type triply periodic minimal surface (TPMS) networks as a gas turbine effusion cooling layer, augmented with various jet impingement configurations. The study analyzes the internal and external flow characteristics, pressure loss, and overall cooling effectiveness using conjugate heat transfer simulations. The Diamond design is compared to conventional film cooling and micro-hole models within a blowing ratio range of 0.5 to 2.0. The jet hole diameter and jet-to-plate distance are varied to identify an optimal double-wall cooling configuration. The results reveal that the Diamond hole mitigates the strong discharge of coolant, resulting in a more adherent cooling film, which provides excellent surface coverage. While jet impingement enhances internal heat transfer, its contribution to cooling effectiveness is minor compared to the benefit of film coverage. At an equivalent total pressure loss coefficient, the Diamond with impinging jets demonstrates 101% higher cooling effectiveness than the film hole. The thermal-mechanical analysis indicates that the Diamond model exhibits a more uniform distribution of thermal stress and displacement. The average stress is reduced by 44.7% compared to the film hole. This work confirms the TPMS-based effusion as an advanced cooling solution for next-generation gas turbines. Full article

In the global trend towards a sustainable circular economy, incineration technology is widely used for the treatment of municipal solid waste (MSW), as it effectively achieves waste harmlessness, reduction, and energy recovery. During the MSW incineration (MSWI) process, the furnace temperature (FT) is closely linked to pollutant emission concentrations. Therefore, precise control and stable monitoring of the FT are essential for minimizing pollution emissions. However, existing studies generally treat the optimization of FT setpoint value and tracking control as separate issues, lacking a unified optimization framework that can link environmental objectives with control parameters in an online, automatic, and closed-loop manner. To address these issues, a dual-layer optimization control method for FT setting and tracking, aimed at minimizing pollutant concentrations, is proposed. In the first layer, the optimization targets the lowest possible NOx and CO₂ emission concentrations, using a genetic algorithm (GA) to determine optimal FT setpoints. In the second layer, the optimization minimizes the Integral of Time-weighted Absolute Error (ITAE) as the performance index, optimizing the parameters of multi-loop PID controllers via an improved GA. Additionally, an innovative shared-memory judgment mechanism is proposed to transmit process data in real time. Based on residual dynamic correction of the optimization function, an effective double-loop closed control architecture is established. Experimental validation shows that, compared to traditional methods, the optimized control system exhibits faster setpoint value tracking, smaller steady-state errors, and stronger anti-interference capabilities, leading to a significant reduction in pollutant emissions. This study provides a new approach for intelligent optimization control in MSWI with substantial application prospects. Full article