Search Results (160)

This study examined total phenolic release and mass transfer during sequential pyruvic acid (PA) pretreatment and sodium hydroxide (NaOH) extraction of bamboo leaves. A 4 × 4 design comprised PA concentrations of 7.0, 8.0, 9.0, and 10.0% and NaOH concentrations of 3.0, 4.0, 5.0, and 6.0%. Kinetic curves from 40 to 120 min showed rapid release followed by a gradual approach to equilibrium. Normalized conversion F(t) was used to evaluate release progression, and two consistent fitting windows were applied for parameter estimation. The LDF model described the 40, 60, and 80 min data and provided k_f, while the Crank spherical diffusion model described the 80, 100, and 120 min data and provided D_eff. These overlapping windows represent different portions of the same continuous extraction process rather than physically separate stages. Model comparison and predictive validation supported the framework. The characteristic time ratio τ_m/τ_d exceeded 2 under all tested conditions, indicating that external liquid film transfer contributed the greater relative resistance. The condition of 8.0% PA and 5.0% NaOH provided the most balanced performance, yielding 18.55 ± 0.26 mg GAE/g, equivalent to 94.4% of the maximum. These results provide a practical basis for rate control analysis and condition selection. Full article

For unshrouded turbine blades, the high-speed tip clearance leakage flow induced by the pressure gradient on the pressure and suction surface sides significantly increases the thermal load in the turbine blade tip regions. Film cooling technology is an effective measure for reducing the external heat transfer temperature at the blade tips. Novel cooling strategies for the turbine blade tip are introduced to reduce adiabatic wall temperature. Here, the spatial distribution of film cooling effectiveness and the associated flow physics of the rib-slot and trapezoidal-slot tip configurations are investigated numerically and experimentally under transonic conditions. Film cooling effectiveness on the tip is quantified using the pressure-sensitive paint technique. Density ratios of 1.5 and 2.0 are considered, with tip clearances set at 0.7% and 1.5% of the blade height and the cascade exit Mach number set at 1.05. Both the trapezoidal-slot and rib-slot tip cooling approaches are capable of establishing complete film coverage over the tip surface. The rib-slot configuration delivers markedly higher effectiveness values over the mid-chord and trailing-edge regions relative to the trapezoidal-slot design. Conversely, the trapezoidal-slot scheme improves tip aerodynamic performance compared with the rib-slot arrangement, with the benefit being most pronounced in the larger clearance setting. Full article

In the current work, pulsating airflow and an external heat source are proposed to improve the evaporation performance of falling films. A volume of fluid (VOF) multiphase flow model is established based on the commercial software ANSYS Fluent 2023 R1 (ANSYS, Inc., Canonsburg, PA, USA) to simulate the falling film evaporation process. Numerical simulations are conducted under combined working conditions with variable average inlet velocity (u₀), relative pulsating amplitude (A), and wall heat flux (q_w). The spatial and temporal distributions of physical fields are visualized via numerical contours and characteristic curves, and the heat and mass transfer enhancement mechanism is revealed from three aspects, namely, the promotion of driving potential difference by wall heat flux, the increase in heat and mass transfer gradients induced by pulsating airflow, and the synergistic effect of the above two factors. The results indicate that the evaporation ratio (Ψ) increases monotonically with the rise of u₀, with a maximum growth rate of 83.8%. By contrast, under the condition of fixed A₀ = 1 m/s while varying u₀, the evaporation ratio exhibits a convex variation with the relative amplitude A = A₀/u₀, and the global optimal value is achieved at A = 1/6, corresponding to u₀ = 6 m/s and A₀ = 1 m/s. Comparative analysis demonstrates that wall heat flux exerts a more significant influence on evaporation performance than pulsating airflow. Specifically, the evaporation ratio at q_w = 10,000 W/m² is 3~4 times higher than that under the adiabatic wall condition. The reliability of the numerical model is first confirmed by comparing the predictions with published experimental data for vertical falling film evaporation. Based on this validated model, the quantified parametric effects and optimal operating conditions provide practical design references for falling film evaporators in seawater desalination and related thermal separation applications. Full article

In our day-to-day lives, we are regularly exposed to a wide spectrum of dangerous gases. Their origins vary, ranging from industrial activities to objects found within our very homes. Naturally, there is an interest in developing cost-efficient and durable devices that can successfully track these gases within our environment. One such candidate is represented by chemoresistive gas sensors based on metal oxides. This is due to their simple architecture and the possibility of scaling down their size, making them valid contenders for future advancements in portable gas sensors. This review focuses on chemoresistive gas sensors that have been obtained through different Physical Vapor Deposition (PVD) methods, which are easily scalable for potential technological transfer towards commercialization or are already exploited at the industrial level, and how varying different deposition parameters impacts the structure of the active material, thus modifying the gas sensing properties of the device. In this review, we report results obtained for different metal oxides: WO₃, ZnO, CeO₂, TiO₂, NiO, and SnO₂. The main findings of these studies revealed that the sensor’s response was highly impacted by oxygen deficiencies within the deposited material, the specific surface area, and the thickness of the film. Moreover, this study also delves into different strategies of functionalization that result in improved gas sensing properties. Thus, we herein report how tailoring functional properties modifies the gas sensing performance of different metal oxides. Full article

Residual stress in brittle films on compliant substrates is routinely inferred from fragmentation experiments by combining an elastic stress-transfer model with a fracture strength criterion. This inversion is inherently coupled because the observed crack spacing depends jointly on the residual stress and the film fracture strength. Conventional closed-form estimators typically rely on a single feature, such as the cracking onset strain, and prescribe the fracture strength a priori, often at its bulk value. This practice discards most of the information encoded in the full crack-spacing evolution. It also obscures two sources of uncertainty: the intrinsic variability of thin-film fracture strength and the limited sensitivity of any single observable to individual parameters. Here, we recast the inversion as a Bayesian physics-informed neural network (B-PINN) in which the entire measured curve of the mean crack spacing versus applied strain is likely to occur. Stochastic gradient Langevin dynamics then sample the joint posterior of residual stress and fracture strength. A central finding is that crack-spacing data alone constrain only the difference between fracture strength and residual stress, confining the posterior to a one-dimensional manifold in parameter space and leaving each quantity individually unresolved. A single substrate curvature measurement, which, through the Stoney relation, depends on the residual stress but not on the fracture strength, provides the missing orthogonal constraint and collapses the posterior to a tight, well-resolved region. We further derive an identifiability condition under which buckle-wavelength observations serve as a third independent channel for recovering interface adhesion energy, and provide a synthetic proof-of-concept of this three-channel extension on DLC/Si and Mo/Si datasets; an experimental validation of the adhesion channel is identified as the natural next step but lies beyond the present scope. Requiring only standard fragmentation measurements and a single non-destructive curvature scan, the framework converts a point-estimate procedure into a posterior-quantified inverse method that makes explicit what can, and cannot, be learned from thin-film mechanics experiments. Full article

The long-term stability of biodegradable polymer coatings deposited by matrix-assisted pulsed laser evaporation (MAPLE) remains insufficiently understood, particularly under ultraviolet irradiation conditions where photochemical effects may accompany material transfer. In this work, thin films of poly(lactide-co-caprolactone)-block-poly(ethyleneglycol)-block-poly(lactide-co-caprolactone), also known as PLCL-PEG-PLCL, are deposited from chloroform solutions by UV-MAPLE using a nanosecond Nd:YAG laser operating at 266 nm over a wide laser fluence range (0.25–0.9 J/cm²). The effect of laser fluence on the morphological, structural, and chemical evolution of the coatings is investigated by atomic force microscopy (AFM), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FTIR), energy-dispersive X-ray spectroscopy (EDS), focused ion beam scanning electron microscopy (FIB-SEM), and X-ray diffraction (XRD). At low laser fluence, relatively homogeneous coatings are obtained while largely preserving the characteristic functional groups of the triblock copolymer. Increasing the laser fluence progressively induces surface restructuring phenomena, including droplets, wrinkles, and the appearance of highly symmetric faceted structures. These entities develop preferentially in samples deposited at elevated fluence and frequently appear only after prolonged aging under ambient conditions, revealing delayed recrystallization behaviour associated with metastable species generated during the deposition process. EDS analyses reveal localized chlorine enrichment within the faceted structures, while FIB-SEM investigations show porous internal morphologies. XRD confirms that the polymer matrix remains predominantly amorphous. The combined observations suggest that UV-MAPLE deposition from chloroform involves not only physical material transfer but also photochemical processes that promote decomposition, recombination, and delayed crystallization phenomena. A phenomenological model describing the successive stages of surface evolution, aging, and recrystallization is proposed. These results provide new insight into the long-term evolution of laser-deposited biodegradable polymer coatings and highlight the importance of solvent selection and processing conditions in determining their stability. Full article

To develop eco-friendly and highly efficient fruit and vegetable preservation materials, this study uses the multi-gradient micro–nano roughness structure and bioactive properties of orange peel as a biomimetic model, aiming to construct a functional film with a unique dual mechanism of physical barrier protection and active preservation. Using soft etching and secondary transfer methods, with polydimethylsiloxane as an intermediate template, and through a repeated freeze–thaw cross-linking process, a polyvinyl alcohol system containing orange peel essential oil was cast to successfully prepare a biomimetic film featuring the micro–nano hierarchical structures found on the surface of orange peel. The study indicates that the biomimetic film accurately replicates the cross-scale hierarchical structures of the natural orange peel surface. Structure–property relationship analysis revealed that the biomimetic film containing 15% orange peel essential oil exhibited the optimal comprehensive performance, characterized by significantly enhanced tensile strength and improved water vapor barrier properties, while demonstrating effective antioxidant and regulated antibacterial activities. Crucially, compared to conventional flat active films, the replicated multi-scale surface roughness provides clear functional advantages by physically optimizing interface properties and cooperating synergistically with the chemical vapor release of the essential oil. Blueberry preservation experiments confirmed that the biomimetic film successfully maintains fruit firmness, vitamin C, and anthocyanin content, while suppressing weight loss and decay rates. This study simulates the microenvironmental control mechanisms of orange peel, highlighting the scientific novelty of structural–chemical synergistic design for advanced functional packaging. Full article

With the expansion of modern protected agriculture, the amount of post-harvest tomato biomass has increased sharply. Conventional unmanaged disposal practices disrupt carbon flows and cause substantial environmental emissions. Tomato plant residues (TPRs), which are rich in lignocellulose and selected high-value secondary metabolites, have considerable potential as feedstocks for green industrial materials. However, their complex biophysical properties, high physiological moisture content, and recalcitrant cell-wall barriers hinder large-scale processing. This review systematically examines the mechanisms and process architectures for converting TPRs into macromolecular products. First, it analyzes cross-scale anatomical heterogeneity and dynamic rheological properties of TPRs, defining their physicochemical boundaries as industrial precursors. Second, it summarizes the development of physical field-coupled equipment, ranging from anti-tangling harvest-shredding to die-roller densification. Furthermore, it examines the core mechanisms of multi-field-coupled pretreatment technologies, including steam explosion, deep eutectic solvents (DES), and mechanochemistry, in deconstructing vascular skeletons and reducing multiphase mass-transfer resistance. Finally, this review discusses reconstruction pathways for TPR-derived components in advanced polymer materials, including biodegradable nanocellulose films, bio-based composites, aerogels, and lignin-based polyurethane networks. Overall, it links microscopic reaction kinetics with macroscopic equipment engineering, proposes a closed-loop material conversion system from in-field volume reduction to cascaded biorefinery, and provides an engineering framework for future multi-machine intelligent collaboration and continuous production across the industrial chain. Full article

This study investigated porous materials based on cellulose acetate (CA), poly(lactic acid) (PLA), and their multilayer combinations fabricated by solution blow spinning (SBS) for potential food packaging applications. Single-layer neat polymers and multilayer structures (CA/PLA, CA/PLA/CA, and PLA/CA/PLA) were produced through sequential deposition, enabling control of layer arrangement while preserving high porosity. Attenuated total reflectance Fourier-transformed infrared spectroscopy, differential scanning calorimetry, and thermogravimetric analysis showed negligible polymer interdiffusion or specific intermolecular interactions, indicating that layer integration occurs mainly through physical contact and void filling rather than molecular mixing. Scanning electron microscopy analysis revealed that cellulose acetate possesses a highly porous, interconnected structure, whereas poly(lactic acid) exhibits a predominantly fibrous morphology with clearly distinguishable layers in multilayer systems. Mechanical testing demonstrated that poly(lactic acid) mats had higher stiffness and tensile strength, while cellulose acetate films were more flexible and compliant. Multilayer systems showed complex tensile behavior characterized by interfacial failure and limited load transfer, indicating no synergistic mechanical reinforcement between layers. Water vapor permeability remained high and narrowly distributed for all configurations (890–920 g·m⁻²·day⁻¹), independent of layer sequence, reflecting the porous morphology. These values exceed those of conventional polymer packaging films, highlighting the suitability of the materials for breathable packaging. Overall, solution blow spinning enables scalable fabrication of biodegradable multilayer materials with tunable mechanical performance for sustainable food packaging applications requiring controlled moisture exchange. Full article

Methane source-rate inversion from remote-sensing plume imagery is essential for emissions monitoring, but its accuracy is often limited by uncertainty in ancillary wind information. This study examines how physical knowledge can be integrated into a deep-learning inversion model when the available wind input is imperfect. Using a controlled large-eddy-simulation (LES) benchmark designed for EnMAP/PRISMA-style imaging-spectrometer methane quantification, we compare six models that span image-only regression, flexible wind conditioning, simplified hard integrated-mass-enhancement (IME) coupling, and soft physics-guided learning under clean inputs, deterministic wind bias, stochastic Gaussian wind noise, and source-rate-stratified tests. Under clean benchmark conditions, flexible wind conditioning provides the best scalar accuracy, with FiLM reaching a mean absolute percentage error (MAPE) of 6.19% and a root mean squared error (RMSE) of 1323.36, followed closely by Concat (MAPE 6.37%, RMSE 1325.69). The simplified hard-coupling model is sensitive to wind perturbations: DIN-hard rises from MAPE 8.44% under clean inputs to 31.39% and 26.89% under deterministic wind-bias multipliers α = 0.7 and α = 1.3, respectively, and becomes unstable under stronger Gaussian wind noise in the tested protocol. By contrast, DIN-soft-v2 remains competitive under clean conditions (MAPE 6.39%, RMSE 1360.94), follows smoother degradation under biased or noisy wind, and improves plume spatial diagnostics relative to DIN-soft (center-of-mass shift 3.92 versus 4.07 pixels; plume alignment degree 2.60 versus 2.72 degrees). The calibrated IME-style physical baseline reaches a clean MAPE 24.45%, indicating that the learning-based models substantially outperform this benchmark physical proxy. Within this LES-based benchmark and the tested wind-perturbation protocols, the results suggest that IME-inspired physical knowledge is more robustly incorporated as a calibratable soft prior than as the simplified hard log-additive forward coupling considered here; however, transfer to real satellite scenes still requires validation. Full article

Colloidal quantum dots (CQDs) are ideal for room-temperature gas sensors due to their high surface area, abundant dangling bonds, and excellent film-forming properties. However, the underlying conduction mechanism remains unclear, lacking in-depth analysis of gas–solid charge transfer and carrier transport, which hinders the rational design of high-performance gas sensors. To address this, we fabricated a PbS colloidal quantum dot thin-film transistor (TFT) gas sensor that enables in situ analysis of carrier concentration and mobility via gate voltage modulation. We systematically measured the variations in conductivity, carrier concentration, and mobility with NO₂ concentration and established a normalized weight variation model. The results show that the conductivity increase upon NO₂ exposure is primarily due to the rise in carrier concentration induced by gas adsorption. At low concentrations (below 0.5 ppm), the response is dominated by mobility variation. This work provides a physically meaningful theoretical framework for understanding the conduction mechanism. Full article

Chloride-induced corrosion of steel reinforcements is one of the main factors restricting the durability of reinforced concrete structures. Chromium (Cr) alloying is an effective strategy to enhance the corrosion resistance of steel. However, the appropriate Cr content for different environments remains undetermined. In this study, steels with three different Cr contents of 0, 5, and 10 wt.% were prepared. Electrochemical methods and physical characterization techniques were used to investigate the effects of Cr content on the passive film and corrosion behavior of steels in a simulated concrete pore solution under chloride attack. The results show that Cr alloying increases the critical chloride concentration for steel depassivation, passive film resistance, and charge transfer resistance. Specifically, the critical chloride concentrations of 0Cr, 5Cr, and 10Cr are 0.63, 0.81, and 1.56 mol/L, respectively. In a simulated pore solution with 0.6 mol/L chloride, the charge transfer resistances of 0Cr, 5Cr, and 10Cr are 4.1, 5.8, and 63.4 × 10⁵ Ω·cm², respectively, corresponding to corrosion rates that are 1.39- and 15.31-times lower for 5Cr and 10Cr relative to 0Cr. Therefore, in concrete exposed to marine chloride attacks, the use of high Cr alloying is necessary. Although the cost increases and the weldability deteriorates, the improvement in corrosion resistance is far superior to that of medium Cr alloying. The excellent corrosion resistance of high-Cr steel stems from its passive film mainly composed of stable Cr₂O₃ with a lower oxygen vacancy defect density, while that of 5Cr is dominated by less stable Cr(OH)₃, which weakens the corrosion resistance of the passive film. Full article

Carbon nanotube (CNT) materials exhibit ultrahigh electrical and thermal conductivity. Upon electrical excitation, CNT-based transparent conductive films (TCFs) can emit far-infrared radiation (FIR) and provide certain physiotherapeutic efficacy, making them ideal candidates for thermotherapy applications. This work systematically tests and analyzes the fundamental physical properties and physiotherapeutic performance of CNT flexible thin-film heaters (TFHs) for potential use in health physiotherapy. Two types of TFHs with different electrode connection modes were fabricated via the prepared TCFs. Experimental characterizations were conducted on their response time, electrothermal performance, and heat transfer characteristics. The results showed that the temperature rise per unit input power for TFH1 was 16.71 °C/W, while that of TFH2 was 4.29 °C/W at the same voltage of 10 V. In addition, the variation trends of maximum temperature with power density were highly consistent for the two films. This demonstrates that TFHs fabricated using the same TCFs exhibit excellent and high electrothermal conversion efficiency as well as outstanding comprehensive electrothermal performance. In addition, smaller L/W ratio leads to lower resistance of TFHs, resulting in a stronger thermal effect under identical applied voltage. After the temperature stabilized, the surface temperature of the TFHs decreased by approximately 5 °C when attached to the human arm, confirming that the heat generated by the TFHs under electrical excitation could be effectively absorbed by the human body. The TFHs emitted rapid FIR upon electrification, and the peak wavelength ranged from 8 to 12 µm, which fell within the range of 6–14 µm that was easily absorbable by the human body. The heat can be rapidly absorbed by the skin and distributed throughout the body via blood circulation, yielding favorable physiotherapeutic efficacy. This study provides key physical parameters for the application of TFHs in wearable medical devices and physiotherapy equipment. Full article

Triboelectric nanogenerators (TENGs) offer a promising route for self-powered microscale energy harvesting, yet their design optimisation remains empirically challenging due to the complex interplay of material surface physics, device geometry and operating mode. In this work, we present an integrated framework that combines atomic force microscopy (AFM) characterisation, COMSOL Multiphysics 6.0 finite element simulation and physics-informed conditional variational autoencoder (cVAE) to predict and optimise TENG output performance. Four polymer dielectric materials, HDPE, LDPE, TPU, and PMMA, were characterised via Kelvin Probe Force microscopy (KPFM) for work function, surface potential and surface roughness. Surface charge density was calculated from measured KPFM potential using the parallel plate capacitor model and used as a boundary condition in COMSOL Multiphysics simulations for contact-separation and lateral sliding TENG mode for dielectric film thicknesses of 50 µm and 100 µm. The simulated open circuit voltage (Voc) and short circuit charge (Qsc) across gap distances up to 150 mm formed the training dataset for a cVAE model with eight physicochemical condition features. The trained model demonstrated strong reconstruction accuracy (R² ≥ 0.94) and enables generative prediction across unseen design spaces. Results reveal that the LDPE/TPU pair at 50 µm thickness consistently achieves the highest electric outputs in both modes, and the sliding mode yields 25–30% higher voltages than the contact separation mode across all material pairs. This study provides a transferable data-efficient methodology for accelerating TENG material and geometry optimisation. Full article

The widespread presence of stable and hazardous organic contaminants, such as synthetic dyes, in industrial effluents necessitates the development of resilient treatment strategies capable of achieving efficient degradation and decolorization of dye pollutants. Conventional treatment processes often fail to remove such recalcitrant compounds, prompting growing interest in integrated advanced systems. Photocatalytic membranes represent a promising solution due to the synergistic combination of physical separation and catalytic degradation. In this study, zinc oxide (ZnO) thin films were deposited by spin coating onto smectite–zeolite ceramic membranes (MS10/Z90), applying one (M1), two (M2), and three (M3) successive coating layers to control catalyst thickness. SEM analysis confirmed that increasing the number of layers resulted in a thicker and more homogeneous ZnO coating, while XRD revealed enhanced crystallinity and larger crystallite size. Water permeability decreased progressively from 623 L·h⁻¹·m⁻²·bar⁻¹ for the uncoated membrane to 506, 439, and 350 L·h⁻¹·m⁻²·bar⁻¹ for M1, M2, and M3, respectively. Photocatalytic performance was evaluated using Rhodamine B (RhB) (10 mg·L⁻¹) under UV irradiation (365 nm, 18 W) for 180 min, achieving degradation efficiencies of 83.0%, 94.6%, and 99.1% for M1, M2, and M3, respectively. The degradation kinetics followed a pseudo-first-order model, with rate constants increasing with catalyst layer thickness. Free radical scavenging assays confirmed that hydroxyl radicals (•OH) were the primary reactive species responsible for RhB degradation. These findings highlight the critical influence of ZnO layer thickness and mass transfer on photocatalytic performance, demonstrating the potential of ZnO-coated ceramic membranes for efficient pollutant degradation and in situ photocatalytic regeneration. Permeability measurements after photocatalytic treatment confirmed effective flux recovery, supporting the operational durability of the developed membranes. Full article