Search Results (5,739)

The generation of aerosols with narrow droplet-size distributions remains a key challenge in liquid atomization technologies used in agricultural, chemical-processing, and environmental applications. This study presents an experimental investigation of spray characteristics produced by an inertial rotary atomizer equipped with an internal hydrodynamic flow-conditioning system. The experiments were conducted using a Box–Behnken experimental design and Response Surface Methodology (RSM). Fifteen experimental runs, including three center-point replicates, were performed to evaluate the combined effects of the operating parameters. Liquid flow rate, rotor rotational speed, and spraying height were selected as independent variables. The response variables included the characteristic droplet diameters (d₁₀, d₅₀ and d₉₀), the Span coefficient, and droplet deposition density (N). Quadratic regression models were fitted to the experimental data to explore the influence of the operating parameters on spray characteristics; however, statistical diagnostics indicated limited predictive capability, and the models were therefore used primarily for exploratory interpretation of response trends within the investigated design space. The experimental results indicated that rotor speed exhibited the strongest tendency to influence droplet-size characteristics within the investigated operating range, while increasing liquid flow rate was associated with larger droplet diameters, consistent with the expected effect of increased liquid-film thickness. Within the investigated atomizer configuration, relatively narrow droplet-size distributions were experimentally observed under selected operating conditions. These observations are consistent with the hypothesis that internal hydrodynamic flow conditioning may contribute to liquid-film destabilization and subsequent breakup. However, its independent contribution cannot be isolated from the present experiments because an otherwise identical baseline atomizer without the flow-conditioning element was not tested. Within the model-predicted favorable operating region (liquid flow rate of 1.0 × 10⁻⁶ m³·s⁻¹, rotor rotational speed of 4600–5100 min⁻¹, and spraying height of 30 cm), the fitted response-surface model predicted a volume median droplet diameter of approximately 64 μm. Separately, the minimum experimentally observed Span coefficient was approximately 0.58, indicating a relatively narrow deposited-droplet-size distribution within the investigated operating range. This model-predicted region was not independently verified by a dedicated confirmation experiment and therefore should not be interpreted as an experimentally validated optimum. The proposed physical interpretation considers hydrodynamic flow conditioning as a plausible additional mechanism contributing to spray uniformity, although its quantitative validation requires dedicated flow diagnostics and CFD analysis. The obtained results characterize the spray behavior of the developed atomizer within the investigated operating domain and provide an experimental basis for future comparative studies aimed at quantifying the independent contribution of the internal flow-conditioning system. These findings provide experimental evidence supporting further investigation of this concept and may contribute to the development of rotary atomizers for precision agricultural spraying and other engineering applications requiring controlled droplet-size distributions. Full article

To investigate how the position and thickness of ultrathin Al interfacial layers regulate the optoelectronic properties and temporal stability of AZO/Cu/AZO multilayer films, AZO/Cu/AZO (ACA), AZO/Al/Cu/AZO (AACA), and AZO/Al/Cu/Al/AZO (AACAA) multilayers were deposited on glass substrates by magnetron sputtering. For clarity, the stack notation is given from the film surface toward the substrate. AACA contains a 1 nm Al interfacial layer above Cu, whereas AACAA-1 and AACAA-2 contain Al layers on both sides of Cu with top/bottom thicknesses of 1/1 and 2/1 nm, respectively. The effects of Al layer insertion position and thickness on the microstructure, optoelectronic properties, and temporal stability were systematically investigated. The ACA and AACA films exhibited ZnO and Cu phases with preferred ZnO (002) and Cu (111) diffraction, respectively. The AACA film showed the best initial optoelectronic performance, with the average transmittance increasing from 75.9% to 85.7% and the sheet resistance decreasing from 18.5 to 6.7 Ω/sq, yielding a figure of merit (F_OM) of 3.2 × 10⁻² Ω⁻¹. After the additional Al layer was introduced beneath Cu, the Cu (111) signal became very weak and the sheet resistance increased markedly, indicating a substantial change in the structural and interfacial state of the ultrathin Cu layer. After two years of air exposure, pronounced Cu-O-rich particles were observed on the ACA surface, and the relative changes in average transmittance and sheet resistance reached 10.7% and 95.7%, respectively. In contrast, the corresponding changes for AACAA-2 were only 1.2% and 2.7%, demonstrating the best temporal stability. These results reveal a clear trade-off between initial optoelectronic performance and long-term stability and show that dual Al interfacial modification is an effective route for stabilizing AZO/Cu/AZO multilayer electrodes. Full article

As the primary carrier for oil and gas transportation, pipelines are critical for the entire industry. Pipelines are continuously subjected to corrosion and abrasion in the oil and gas delivery process, leading to gradual wall thickness reduction, shortened service life, and deteriorated operational safety. Ultrasonic testing has been widely adopted for monitoring pipeline wall thickness. Conventional ultrasonic transducers possess rigid configurations, which hinder large-area inspection and exhibit poor adaptability to complex curved components. In contrast, flexible ultrasonic sensors show prominent advantages, with their small size, light weight, and excellent conformal contact with curved surfaces. Flexible piezoelectric thin-film sensors have been used in a wide range of fields. As one of the most representative piezoelectric polymers, poly(vinylidene fluoride–trifluoroethylene) (P(VDF-TrFE)) combines favorable piezoelectric coefficients and intrinsic flexibility, making it popular. Some research groups have investigated the influences of modified filler particles, doping ratios, and fabrication process optimization on the performance of P(VDF-TrFE)-based piezoelectric composites, while others have concentrated on the practical applications of existing flexible piezoelectric sensors. This study emphasizes a rapid customized fabrication strategy for flexible sensors instead of single-specification standardized probes; hence, it does not share the same comparison benchmark as conventional fixed-dimension sensors. Systematic research on flexible piezoelectric thin-film sensors is presented, including piezoelectric material modification, substrate design, laminated structural design, fabrication workflows, establishment of the testing platform, and the development of matched circuit systems. The material preparation and manufacturing processes are optimized, and a scalable technical route for fabricating flexible piezoelectric sensors is proposed. Using this route, flexible piezoelectric thin-film sensors can be rapidly tailored for different application scenarios to satisfy diverse engineering demands. Multiple experiments were conducted on pipeline samples with varying wall thicknesses and curvatures. The results verify that the sensor reaches a measurement precision of 0.01 mm, meeting the demands of high-precision pipeline structural health monitoring. Full article

Poly(vinyl alcohol) (PVA)–bentonite composite coatings combine a hydrophilic polymer with a naturally abundant clay mineral, offering potential advantages for modifying the physicochemical and film-forming characteristics of polymer–clay coatings. However, the combined influence of PVA–bentonite composition and total solids content on drying behavior and film evolution remains insufficiently explored. This study investigates the particle size, X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), surface morphology, rheology, thixotropy, zeta potential, drying behavior, solvent transport, and film evolution of PVA–bentonite coatings prepared at total solids contents of 5 and 10 wt.% with different PVA to bentonite ratios. The drying profiles exhibited an initial relatively rapid solvent-removal stage followed by a slower stage associated with progressively restricted solvent transport during film consolidation. A lower total solids content (5 wt.%) generally accelerated drying but was associated with greater microcracking, whereas a higher total solids content (10 wt.%) produced more consolidated and comparatively uniform films with reduced solvent mobility. The combined physicochemical, rheological, drying, and morphological results demonstrate that both PVA–bentonite composition and total solids content substantially influence the structural organization and drying behavior of the coatings. Pure PVA formed a relatively uniform film but exhibited prolonged drying, while pure bentonite required the longest drying time (1083 min). Among the investigated formulations, the 50:50 PVA–bentonite coating demonstrated the shortest drying time, reaching equilibrium in approximately 480 min, while also exhibiting comparatively good film uniformity. During drying, its thickness decreased from approximately 1745 to 440 µm, corresponding to a reduction of about 1305 µm. Overall, under the investigated laboratory conditions, the 50:50 PVA–bentonite formulation provided the most favorable balance of drying behavior, film formation, and rheological characteristics among the compositions studied. These findings provide composition–structure–drying relationships that can guide further development of PVA–bentonite coating systems. At the same time, additional evaluation of mechanical, adhesion, barrier, durability, and economic performance is required to establish broader practical applicability. Full article

Dichromatic optical interferometry provides rich optical information for lubricant film-thickness measurement. However, experimental data are typically limited to a small number of discrete operating conditions, making it difficult to learn the nonlinear relationship among entrainment speed, dichromatic interference images, and lubricant film thickness. To address this limitation, a Dual-Wavelength Physics-Guided Graph Neural Network (DW-PG-GNN) is proposed for intermediate lubrication-state characterization from sparse experimental observations. Rather than directly regressing film thickness from interference images, the proposed framework learns the nonlinear relationship among entrainment speed, dichromatic interference images, and lubricant film thickness through a unified physics-guided learning framework. Specifically, graph representations capture the structural continuity and cross-wavelength coupling characteristics of dichromatic interference fringes, while a physics-guided residual learning strategy embeds analytical film-thickness priors from classical elastohydrodynamic lubrication (EHL) theory into an implicit neural representation for intermediate state prediction. A differentiable interference renderer further constrains the consistency between predicted film thickness and reconstructed dichromatic interference images, ensuring optical and physical consistency throughout the learning process. Validation based on sparse experimental datasets acquired from a ball-on-disc EHL rig demonstrates reliable average film-thickness prediction and interference-image reconstruction under the investigated operating conditions. The prediction errors remain within 2.2% for trained conditions and 8.67% for unseen entrainment-speed interpolation conditions. Full article

Flexible transparent conductive films with symmetric and asymmetric multilayered structures are studied using the ZnS–TiO₂–Ag material system, in order to capitalize on the divergent properties of the two dielectric layers for improved performance. The dielectric/metal/dielectric-structured films were deposited by magnetron sputtering sequentially, with high-purity targets. Multilayered films with various dielectric combinations and metallic layer thicknesses were prepared and analyzed. The surface morphology and phase structure were characterized by atomic force microscopy and scanning electronic microscopy. The optical properties were tested by spectrophotometry and analyzed by numerical simulation approach. The sheet resistance was measured via a four-point probe tester. Among the series of multilayers, asymmetric ZnS/Ag/TiO₂ film with 35 nm thickness of dielectric layers and 8.5 nm of metallic layer possesses the optimum comprehensive optoelectronic performance. The average light transmittance reaches 90.72% in the visible spectrum, and the sheet resistance is 7.69 Ω/sq. The good result is ascribed primarily to the combined advantages of superior percolation effect of bottom ZnS layer on ultrathin Ag layer, beneficial impingement effect of top layer deposition on the metallic layer, and excellent surface smoothness of the top dielectric layer. Full article

Infrared-selective stealth films, which concurrently offer high visible transmittance, suppressed infrared emission, and selective thermal dissipation, have emerged as compelling candidates for infrared protection and thermal-target stealth. However, traditional multilayer architectures are predominantly designed through empirical trial-and-error protocols, which inherently hinder the synergistic optimisation of multiband spectral performance and yield suboptimal parameter-tuning efficiency. To circumvent this bottleneck, we introduce a reinforcement learning (RL)-driven multi-objective optimisation framework that automates the design of composite thin-film configurations. The optimised multilayer film structure consists of TiO₂/ITO/Ag/ZnO/SiO₂, with layer thicknesses of 180, 656, 10, 33.75 and 50 nm, respectively. Spectral characterisation reveals a weighted average visible transmittance of 79.77% over the 0.38–0.78 μm range, alongside blackbody-weighted average emissivities of 33.93%, 72.93%, and 19.94% in the 3–5, 5–8, and 8–14 μm bands, respectively. Consequently, the spectral profile exhibits high visible transparency, deep suppression of emissivity within the atmospheric windows (3–5 and 8–14 μm), and markedly elevated emissivity in the non-atmospheric band (5–8 μm). Analysis of the electromagnetic field distribution and power-loss density along the thickness direction reveals that the energy transmission and dissipation behaviours across distinct bands are synergistically governed by multilayer interference, interfacial multiple reflections, and lossy interlayer coupling mechanisms. Furthermore, angle-resolved infrared-emissivity analysis calibrated against the normal-incidence FDTD spectrum confirms that the structure retains robust polarisation adaptability and pronounced spectral selectivity at incidence angles up to 80°. The above results demonstrate the effectiveness of the reinforcement learning-driven optimisation framework for the automated co-design of multiband spectral responses. Moreover, the uncovered multilayer interference and loss-coupling mechanisms furnish a solid physical foundation for further performance refinement and rational design of transparent stealth coatings. Full article

Integrated electrochemical sensors (IESs) offer rapid and efficient detection of environmental pollutants, but their broader practical implementation requires overcoming common challenges associated with reproducible fabrication and long-term stability. In this work, these challenges were addressed using a thick-film approach to fabricate IESs with graphite-glass, glassy carbon, and carbon black working electrodes (WEs) by screen printing followed by firing at 850 °C. The relationship between the structure of the carbon-based WEs and the electrochemical performance of the IESs was systematically investigated using cyclic voltammetry (CV) in combination with X-ray powder diffraction, transmission electron microscopy (TEM), and scanning TEM. The analyses revealed distinct morphologies and structural ordering of the carbon WEs, which directly affect their electron-transfer kinetics, adsorption behaviour, capacitive response, and electrochemically active surface area. The ordered structure of the graphite-glass WE was associated with lower capacitance and faster electron-transfer kinetics, as determined from the CV response of the IES. In contrast, the disordered structure of the carbon black WE was associated with higher capacitance and slower kinetics of the IES. The glassy carbon-based IES exhibited kinetics similar to those of the carbon black-based IES, but with the lowest capacitance, resulting in the greatest signal definition. Consequently, although all IESs exhibited wide operating potential windows (−1.6 V to +1.0 V vs Ag/AgCl) and fast heterogeneous electron-transfer kinetics towards the [Fe(CN)₆]^3−/4− redox probe (7.6 × 10⁻³–15.5 × 10⁻³ cm s⁻¹), the carbon materials differed in their electrochemical response and signal definition. Importantly, all IESs demonstrated excellent reproducibility (relative standard deviation < 2.4%), operational stability with less than 5% signal loss after 1000 CV cycles, and shelf-life stability exceeding 30 days. These findings demonstrate that tailoring the carbon structure of the screen-printed thick-film WEs enables reproducible fabrication of stable and reliable IESs while providing a versatile strategy for tuning their electrochemical performance towards application-specific requirements. Full article

To reveal how meniscus dynamics affect wet film uniformity during slot-die coating for perovskite solar cell manufacturing, a 2D numerical model employing the VOF method is established for perovskite precursor fluids. A photoresist is used as a qualitative substitute liquid for auxiliary experimental validation, and dry film thickness is measured to characterize the relative uniformity of wet coating. The results show that the capillary number governs the upstream meniscus shape. Inlet velocity, slot gap, and coating gap influence film thickness by altering the downstream meniscus climbing height. Optimal film thickness uniformity is achieved when the pre-coating liquid volume accounts for about 31% of the total coating volume; this empirical optimal ratio is only valid within the tested inlet flow rate range under the fixed experimental conditions adopted in this work, and further multi-parameter verification under diverse process windows will be carried out in follow-up research. Full article

Complex surfaces exhibit hierarchical morphological organizations that cannot be fully described by conventional roughness parameters alone. In this study, a fractal–statistical framework is proposed to elucidate the substrate-controlled morphological evolution of 2,6-diphenyl anthracene (DPA) thin films deposited on chemically modified dielectric substrates, including hexamethyldisilazane (HMDS), octyltrimethoxysilane (OTMS), octadecyltrichlorosilane (OTS), and bare silicon dioxide (SiO₂). A multidimensional morphological descriptor vector (M_DPA) is introduced by integrating ISO 25178 areal surface parameters (H_ISO), fractal dimension (D_f), texture direction parameters (T_d), power spectral density (PSD), and scale-sensitive fractal analysis (SSFA) descriptors to quantify amplitude-based, spatial-frequency, and scale-dependent morphological information. Atomic force microscopy (AFM) topographies of 5 nm and 50 nm thick films were analyzed using complementary approaches, including ISO 25178 areal surface parameters, texture direction analysis, peak statistics, morphological envelope fractal analysis, two-dimensional Fourier analysis, power spectral density (PSD), and scale-sensitive fractal analysis (SSFA). The results demonstrate that substrate chemistry governs not only the amplitude of surface roughness but also the lateral organization, spatial frequency distribution, and scale-dependent fractal complexity of DPA morphologies. The fractal dimension analysis revealed substrate-dependent variations in surface complexity, with values ranging from 2.11 to 2.45 for 5 nm films and from 2.19 to 2.52 for 50 nm films. PSD analysis identified distinct substrate-induced modifications in spectral organization, while SSFA revealed significant changes in smooth–rough crossover scales, maximum complexity scales, and fractal surface complexity during film growth. In particular, OTMS promoted the strongest hierarchical organization for thicker films, exhibiting the highest scale-sensitive fractal complexity, whereas OTS generated highly developed but less hierarchically correlated rough structures. The integrated fractal–spectral methodology establishes quantitative relationships between substrate functionalization and multiscale surface evolution, demonstrating that morphological complexity cannot be described solely by conventional height parameters. This framework provides a robust approach for characterizing hierarchical thin-film architectures and can be extended to other organic semiconductor systems where substrate-driven morphological control is critical. Full article

This study investigated the development of biopolymer films from bitter cassava starch (Manihot esculenta) and coconut mesocarp cellulose as a promising alternative for biodegradable packaging. The biopolymer film was prepared using the casting method, with glycerol as a plasticiser and Tween 80 as an emulsifier. Different formulations were developed by varying the cellulose concentration to 6%, 8% and 10% to determine how this influences their physical and optical properties. FTIR analysis confirmed the presence of characteristic –OH, C–H, C=O, C–O–C and OH groups in the structure of the cellulose and starch, demonstrating their purity and chemical structure. It was found that the variation in cellulose within the starch polymer matrix significantly influences the microstructural organisation of the material, yielding film thicknesses of between 0.49 and 0.56 mm, with a moisture content ranging from 6.46% to 8.01% and a water absorption percentage between 67.7% and 109.5%; highlighting that the cellulose concentration of 0.4 g (8%) yielded the best results. This research contributes to bridging the existing gap in the utilisation of agricultural waste from bitter cassava and coconut mesocarp, integrating them to form biodegradable composites with potential use in biodegradable packaging, thereby strengthening environmental sustainability through the circular economy. Full article

The static and dynamic magnetic responses of symmetric Fe/Al/Fe trilayers were investigated as a function of the thickness of the nonmagnetic spacer layer thickness, with t_Al ranging from 0 to 2 nm. Samples showed ferromagnetic coupling between Fe layers for all values of t_Al, despite presenting characteristics of low-quality thin films, including high roughness and low-saturation magnetic moments. However, it was demonstrated that inclusion of a thin nonmagnetic Al spacer is an effective method to reduce the effective apparent damping parameter (α_app) of the dominant acoustic mode of the multilayered system. Specifically, α_app was reduced from 0.030 to 0.013 when the Al spacer thickness exceeded the characteristic roughness of the layers (t_Al ≥ 1.4 nm). This reduction coincided with the appearance of distinct acoustic and optical resonance modes, indicating a transition from a direct exchange-coupled regime dominated by pinholes to a regime dominated by dipolar coupling. This suggests that decoupling the ferromagnetic layers is a viable strategy for developing low-damping Fe-based materials, even in systems with significant structural imperfections. Full article

Background/Objectives: The buccal mucosa offers a promising non-invasive route for systemic drug delivery, particularly for hydrophilic compounds like captopril (CAP), which exhibit low permeability and are subject to gastrointestinal instability and first-pass metabolism. This study aimed to develop and characterize captopril-loaded, chitosan-based mucoadhesive buccal films with different permeation enhancers and to evaluate their physicochemical properties, drug release, cytocompatibility, and in vitro transport across a TR146 buccal epithelial cell model. Methods: Films were prepared by the solvent-casting method using chitosan as the film-forming polymer. Different enhancers were investigated, including organic acid salts of chitosan (ascorbate, citrate, and lactate) and chemical permeation enhancers (sodium lauryl sulfate, polyethylene glycol 400, Span 20, and EDTA). Results: The resulting films exhibited acceptable thickness, moisture content, appropriate mechanical properties, and good mucoadhesive strength. In vitro dissolution studies demonstrated rapid CAP release, with >50% released within 15 min and near-complete release by 180 min across all formulations. Cytotoxicity assessment via a Neutral Red uptake assay in TR146 cells confirmed high cell viability (>81%) after 4 h of exposure, indicating good biocompatibility. In vitro permeation experiments revealed that films prepared with chitosan ascorbate and chitosan lactate enhanced CAP transport compared to other formulations, achieving the highest flux and apparent permeability coefficients. Conclusions: These findings demonstrate that chitosan ascorbate and lactate salts effectively improve the buccal permeability of captopril while maintaining good film properties and biocompatibility. This work highlights the potential of chitosan ascorbate- and lactate-based mucoadhesive films as an efficient platform for the buccal delivery of CAP. Full article

High-quality and high-efficiency machining of film cooling holes (FCHs) is critical for enhancing the performance of gas turbines and aero-engines. Nanosecond fiber lasers offer advantages such as high stability, good beam quality, and ease of integration. However, when machining FCHs, issues including low drilling efficiency and significant thermal effects severely limit their industrial applications. In this study, a dual-rotary trepanning system was developed based on a nanosecond fiber laser, a galvanometer, and a five-axis cradle machine. High-quality FCHs with a diameter of 0.6 mm were efficiently machined in a 3-mm-thick DD6 superalloy plate within only 6.5 s. Compared with the method using machine tool rotation alone, the average recast layer thickness on the inner wall was reduced by 62.1% to 6.7 μm, and the average surface roughness was reduced by 61.1% to 0.35 μm. These improvements are primarily attributed to the galvanometer speed being two orders of magnitude higher than that of the machine tool, which significantly reduces the laser pulse overlap rate and the thermal accumulation effect. Moreover, the kerf widened by the galvanometer rotation allows the ablation products to expand more fully and be expelled efficiently, thereby reducing impact, scratching, and debris adhesion on the inner wall and improving the drilling efficiency. Furthermore, 10 × 10 FCH arrays were machined on both vertical and inclined plates, demonstrating high consistency and stability, indicating the potential for industrial applications in the field of FCH machining. Full article

With the rapid development of recycling and secondary utilization of end-of-life battery materials, it is crucial to clarify the impact of full-lifecycle degradation on the thermal safety limits of lithium-ion batteries. This study focuses on a 16 Ah NCM613|graphite pouch battery. First, it analyzes the evolution of capacity decay, thickness expansion, and internal resistance during cycling at room temperature (25 °C) and high temperature (45 °C). Furthermore, an adiabatic accelerated calorimeter (ARC) is employed to investigate the influence of different states of health (SOH) levels (95% and 85%) on the battery’s thermal runaway characteristics. The findings indicate that, macroscopically, batteries in all states follow similar voltage–temperature failure pathways, with mass loss rates confined to a narrow range of approximately 16%, emphasizing the low catastrophic potential of mid-nickel chemistry. However, the microscopic kinetic mechanisms exhibit significant anisotropy: although thickness and internal resistance display no apparent abrupt increase during the late stage of room temperature aging, the capacity exhibits a highly nonlinear plunge behavior. The severe internal lithium plating side reaction triggered by this phenomenon causes the self-heating onset temperature to drop rapidly from 130.0 °C in the fresh state to 79.7 °C. Concurrently, the activation energy of the exothermic side reaction, fitted using a simplified Arrhenius equation, exhibits a non-monotonic variation with aging progress. In the early stages of aging at 95% SOH, due to high temperatures promoting more significant growth of the interfacial film or moderate film formation at room temperature enhancing interfacial thermal stability, the activation energies for both aged batteries increase, and the energy barrier at high temperatures is slightly higher than at room temperature; however, during the deep aging stage at 85% SOH, due to the degradation of active material components and the emergence of lithium plating characteristics, the energy barrier significantly decreases, with high-temperature-aged batteries exhibiting a greater reduction, highlighting the cumulative negative impact of prolonged high-temperature exposure on thermal safety. The research provides a core scientific basis for establishing a battery safety early warning and dynamic health management system covering the entire lifecycle. Full article