Search Results (199)

The edge-defined film-fed growth (EFG) method is the dominant industrial technique for producing large-area β-Ga₂O₃ single-crystal substrates, but thermal stress-induced dislocation generation remains a critical barrier. This work presents a coupled thermo-mechanical finite-element framework for thermal-stress management in EFG-grown β-Ga₂O₃. The central methodological contribution is a 500-sample gradient-boosting surrogate sensitivity analysis ($R^2=0.955$, mean absolute error (MAE) $=11.3$ MPa) that quantitatively decomposes thermal-stress variance into controllable process factors and irreducible material-property uncertainties. The physical foundation comprises two enabling elements: (i) the full 21-component monoclinic Voigt stiffness matrix with explicit crystal–model coordinate mapping, for which the orthotropic model is rigorously shown to be exact in 2D plane strain through an exact kinematic theorem showing that the 2D plane-strain results of prior orthotropic EFG analyses are unaffected by the coupling terms, while the monoclinic formulation provides the essential foundation for future 3D studies; and (ii) a dimensionless and numerical justification for omitting melt convection, which enables 100% solver convergence (500/500 Latin hypercube samples) with stress errors < 1.5 MPa. Afterheater temperature $T_{\mathrm{AH}}$ is the leading controllable parameter (35.9%), nearly tied with the elastic constant $C_{33}$ (35.5%), followed by the thermal-expansion component ${\alpha }_c$ (15.9%). Elevating $T_{\mathrm{AH}}$ from 1900 K to 1950 K reduces the peak von Mises stress by ∼29% (COMSOL Multiphysics 6.2-verified); the 2D plane-strain baseline anchors the surrogate analysis at ${\sigma }_{max}=223$ MPa, while the afterheater-free 3D configuration gives ${\sigma }_{max}=187$ MPa at the crystal periphery near the solid–liquid interface. The isotropic approximation underestimates peak stress by 39.6%, confirming that directional anisotropy is essential for quantitatively reliable thermal stress prediction in monoclinic oxide crystals. Full article

Potato starch extrudates, chemically modified by a K₂CO₃ catalyst and enriched with two types of edible oils (rapeseed or sunflower) at varying concentrations (3%, 6%, 9%), were used as film substrates. This study was carried out as a continuation of previous research on analogous extrudates in the form of dry powders and liquid solutions. The main objective was to determine surface properties of polysaccharide films as a function of oil type and concentration to monitor their wettability, biocompatibility, and functional characteristics (e.g., transparency, colour, thickness, flexibility, solubility). Advancing and receding contact angles for polar liquids (water and formamide) and non-polar diiodomethane were measured on the base and oil-modified extruded starch films. Based on these measurements, the surface free energy of the films was determined using the contact angle hysteresis (CAH) model. Optical profilometry confirmed the wettability results through surface morphology and roughness evaluation. Additionally, FTIR analysis of the films was compared to the FTIR spectra of extruded starch powders. Combining these methods provided an in-depth characterization of the films, thereby improving control over their stability and wettability, which is essential for applications in the pharmaceutical and food industries to extend product freshness and enhance resistance to oxidation and spoilage. Full article

The lubrication performance of high-speed transmission systems directly affects mechanical power consumption and operational reliability. During high-speed oil-stirring lubrication, strong gas–liquid interfacial shear, liquid-film deformation, droplet splashing, and oil-mist transport generate an unsteady multiphase turbulent flow field. Conventional continuum-based numerical methods often face difficulties in resolving interface breakup and transient turbulent dissipation under high-speed rotational excitation. To address this problem, this study develops a coupled Lattice Boltzmann–Large Eddy Simulation (LBM–LES) method for oil–air two-phase flow in a high-speed oil-stirring lubrication system. The D3Q27 discrete velocity model, cumulant collision operator, WALE subgrid-scale model, free-surface tracking, and local grid refinement are integrated to analyze free-surface deformation, oil-mist evolution, and power-loss characteristics. Taking a notched toothless oil-stirring disk as the reference configuration, the effects of oil immersion depth and disk topology on gas–liquid phase distribution, oil-mist coverage, power consumption, and vortex-induced energy dissipation are investigated. The results indicate that oil immersion depth has a nonlinear influence on lubrication performance and power loss. Among the investigated cases, an immersion depth of 20 mm provides a favorable balance between upper-region oil-mist coverage and lower-region oil-pool stability. At this depth, the notched disk exhibits directional oil delivery and relatively low power consumption, whereas the double-rhombus structure expands the oil-mist coverage but increases the average power consumption to approximately 175 W. These findings provide numerical support for balancing oil-mist coverage, mechanical power consumption, and disk topology design in high-speed transmission lubrication systems. Full article

The spreading and film formation of organic polymer solutions on liquid surfaces are key processes in coating, printing, and interfacial processing. However, the mechanisms by which aqueous polymers regulate spreading kinetics and film morphology are not yet fully understood. In this study, the free spreading of Poly(3-hexylthiophene-2,5-diyl) (P3HT)/chlorobenzene solution on poly(vinyl alcohol) (PVA) aqueous surface was employed as a model system to investigate how PVA concentration, molecular weight, degree of hydrolysis, and temperature collectively govern spreading behavior and film formation. Video recording was used to monitor the evolution of the spreading and front-edge morphology, while step-profilometry, UV–visible absorption spectroscopy, and atomic force microscopy were employed to characterize the resulting films in terms of thickness distribution, optical uniformity, and surface roughness. The results reveal that PVA can significantly regulate both the spreading kinetics of P3HT/chlorobenzene droplets and the final film morphology. PVA concentration exhibited a non-monotonic effect on spreading behavior, with intermediate concentrations favoring larger spreading areas and more continuous films. Increasing the PVA molecular weight altered the concentration-dependent spreading window and enhanced asymmetry at the spreading front, whereas reducing the degree of hydrolysis decreased interfacial tension and thereby increased the thermodynamic driving force for spreading, yet the actual spreading rate remained constrained by molecular diffusion, interfacial adsorption, and chain-segment rearrangement. Temperature and a saturated chlorobenzene vapor atmosphere further modulated the interplay among solvent evaporation, interfacial driving force, and viscous dissipation. Under optimized conditions, the resulting P3HT films displayed uniform thickness profiles, consistent optical absorption, and nanoscale surface roughness, and could be repeatedly transferred, assembled into well-defined multilayer structures, and printed onto flexible and curved substrates. These findings demonstrate that PVA aqueous subphase provides a tunable low-shear route for transferable P3HT thin-film fabrication and suggests its potential applicability to other polymer film-forming systems. Full article

The present study investigated the effect of liquid smoke (LS) on the physicochemical, structural, barrier, and functional properties of okra mucilage–corn starch (OMCS) films. Formulations containing varying concentrations of LS (0–3%) were prepared using the casting method. The incorporation of LS modified the rheological behavior of the film-forming dispersions, as evidenced by increased apparent viscosity and consistency index. In the films, water solubility increased from 43.6 to 53.2%, contact angle increased from 31.9° to 55.6°, and opacity increased from 4.73 to 8.83, while water vapor permeability decreased from 1.05 to 0.88 g·mm·m⁻²·h⁻¹·kPa⁻¹, indicating modifications in matrix organization and surface hydrophobicity. Tensile strength increased from 26.3 to 40.5 MPa at 3% LS, accompanied by a slight reduction in elongation, suggesting enhanced structural rigidity. Structural analyses revealed interactions between the LS phenolic compounds and the polysaccharide hydroxyl groups, resulting in a more cohesive polymeric network. LS was the main contributor to the film’s antioxidant activity owing to its elevated phenolic content and free radical scavenging capacity. The films also showed substantial degradation under soil burial conditions, with mass loss ranging from 61% to 96%. Overall, LS proved to be an effective functional additive, improving the structural and antioxidant performance of OMCS films and expanding their potential for active food packaging applications. Full article

A silk fibroin/cellulose inverse-opal photonic crystal composite with robust mechanical properties was fabricated by blending a silk fibroin solution with methylcellulose, utilizing a 3D poly(methyl methacrylate) (PMMA) photonic crystal array as a template, via sequential infiltration, curing, and etching processes. Leveraging the intrinsic water sensitivity of both silk fibroin and methylcellulose, the resulting composite exhibits exceptional moisture-sensing capabilities across gaseous, liquid, and solid phases. Specifically, for atmospheric humidity, the film delivers a distinct optical response to a relative humidity variation in merely 5%. In liquid systems, owing to the material’s excellent affinity for low-polarity organic solvents and the disruptive effect of highly polar solvents (e.g., water) on the photonic periodic structure, the structural color of the film can sensitively report trace water contents down to 0.025%. Furthermore, in solid matrices, the composite enables the precise detection of not only free water but also water of crystallization. Full article

To improve the efficiency of jet-based fire suppression for high-rise building façade fires, this study experimentally investigates the liquid film formation characteristics and fire suppression behavior of water jets impinging on insulated vertical surfaces. The effects of operating pressure (flow rate), nozzle-to-wall distance, and jet inclination angle on liquid film spreading morphology, wetted area, and effective water supply rate are systematically analyzed. The results show that increasing the flow rate significantly enlarges the wetted area, while reducing the effective water supply rate. As the nozzle-to-wall distance increases, the liquid film gradually develops a “top-wide and bottom-narrow” morphology. Although increasing the jet inclination angle decreases the wetted area, it enhances the continuity and stability of wall-adhering liquid film flow, thereby improving cooling efficiency near the flame root region. During the fire suppression experiments, low-flow-rate jets exhibit insufficient suppression stability, whereas high-flow-rate horizontal jets are capable of suppressing the flame to a residual burning state near the bottom of the façade. Further increasing the jet inclination angle enables complete flame extinguishment. This study reveals the relationship between jet parameters, liquid film behavior, and fire suppression performance, providing experimental evidence for the optimization of jet-based façade fire suppression strategies. Full article

Hydrogen-fueled internal combustion engines (H₂-ICEs) impose unique challenges on engine lubrication because water is an inevitable combustion product. This review summarizes the current understanding of water-induced degradation mechanisms in engine oils for H₂-ICEs, with emphasis on physicochemical property variation, additive depletion, tribofilm evolution, and tribological performance. Water present in dissolved, emulsified, or free states can significantly alter lubricant viscosity, destabilize additive systems, and accelerate oxidative aging. In particular, water promotes the depletion of zinc dialkyldithiophosphate (ZDDP) through tribofilm removal and competitive adsorption at rubbing interfaces, while also inducing additive hydrolysis that transforms long-chain phosphates into shorter-chain species with inferior film-forming capability. These processes inhibit tribofilm growth and reduce the mechanical integrity of protective films, thereby deteriorating anti-wear performance. Although substantial progress has been made in understanding the role of liquid water in lubrication, the tribochemical effects of high-temperature water vapor under realistic H₂-ICE operating conditions remain largely unexplored. Future research should therefore focus on water vapor-dominated lubrication environments representative of hydrogen combustion, aiming to elucidate the underlying tribochemical mechanisms and support the development of dedicated lubricants for durable and reliable H₂-ICE operation. Full article

Imidazole-based ionic liquids hold immense potential in the field of mineral flotation due to their tunable properties. In this study, three imidazole-based ionic liquids with varying carbon chain lengths (OMB, DMB, and HMB) were selected as collectors for quartz flotation to systematically investigate the microscopic mechanisms by which carbon chain length influences the agglomeration and flotation behavior of quartz. Flotation tests and online particle-bubble monitoring (PBM) results indicate that the elongation of the collector’s carbon chain significantly enhances its collecting ability and reduces the required reagent dosage. To achieve the complete recovery of quartz in a neutral system, a dosage of 35 mg/L is required for OMB, whereas HMB requires only 8 mg/L. As the carbon chain lengthens, the optimal pH range for highly efficient flotation shifts from alkaline to neutral-acidic. Interfacial measurements and mechanistic analyses (Zeta potential and FTIR spectroscopy) confirm that the imidazole ring of the collector physically adsorbs onto the quartz surface through the synergistic action of electrostatic forces and hydrogen bonding, thereby inducing the hydrophobic agglomeration of particles. Notably, in a strongly alkaline system (pH = 11), the long-chain HMB promotes the formation of oversized quartz agglomerates. This leads to a depletion of free reagents in the liquid phase and destabilizes the bubble liquid film, ultimately triggering a sharp decline in recovery. Density functional theory (DFT) calculations further corroborate the structure–activity relationship at the molecular level: the extension of the carbon chain increases the highest occupied molecular orbital (HOMO) energy and electron-donating ability. The adsorption energy of HMB on the quartz (001) surface reached −350.2 kJ/mol, exhibiting the strongest solid–liquid interfacial affinity. This study elucidates the competitive mechanism of carbon chain length in regulating electrostatic adsorption, hydrophobic agglomeration, and froth stability, providing a solid theoretical foundation for the molecular design of novel green flotation reagents for quartz. Full article

Localized surface plasmon resonance (LSPR) is an optical phenomenon that occurs when light interacts with free electrons on the surface of metallic thin films, producing intensified electromagnetic fields at specific sites, often called “hot spots”. LSPR-based sensing technologies respond to chemical and associated optical interfacial changes. Inherent advantages include enhanced sensitivity, compact size, low production cost, and strong potential for integration into portable, point-of-care diagnostic systems. This study focuses on a detailed investigation into the surface functionalization of localized surface plasmon resonance (LSPR)-based nanohole array (NHA) sensors for biomedical applications. Gold-coated NHA surfaces were functionalized using polyethylene glycol (PEG) self-assembled monolayers (SAMs), enabling specific attachment of biomolecular species. As a proof-of-concept, bovine serum albumin (BSA) and SARS-CoV-2 nanobody proteins were successfully immobilized on the PEGylated surfaces. Individual steps of surface modification including PEGylation, protein immobilization and nanobody immobilization were validated through a dual-method approach which combined measurement of LSPR optical spectral shifts and x-ray photoelectron spectroscopy (XPS) chemical analyses. Reproducibility was assessed across multiple sensors and repeated trials, confirming the repeatability of each functionalization and binding process. The sensor system, consisting of NHA-based plasmonic platform, microfluidics, and a portable optical spectrometer, exhibits the capability for reliable and sensitive, label-free detection of biomolecular targets, including viral antigens, in liquid-phase environments. Full article

Plasma polymerization offers a solvent-free route to functional polymer materials, but the structural integrity and accessibility of functional groups in plasma-derived networks remain insufficiently validated. Herein, N-vinylimidazole (NVI) was polymerized using atmospheric-pressure dielectric barrier discharge (DBD) plasma in a liquid-film configuration to generate a chemically heterogeneous poly(N-vinylimidazole)-like material that could be recovered and evaluated in aqueous solution. ATR–FTIR and ¹H NMR spectroscopy indicate substantial vinyl-group consumption with retention of imidazole functionality. Functional behavior was probed using chromium(III) (Cr³⁺) as a model metal ion. UV–Vis spectroscopy revealed systematic changes in the Cr³⁺ d–d transition region (~580–600 nm) with increasing polymer concentration, consistent with ligand-field perturbation arising from interactions with imidazole donor sites. A monotonic increase in absorbance with an increasing ligand-to-metal ratio was observed, followed by plateau behavior at higher ratios, indicating saturation of accessible coordination environments. These results demonstrate that plasma-polymerized material retains chemically accessible imidazole functionalities capable of coordinating transition-metal ions in solution, establishing atmospheric-pressure plasma polymerization as a viable route to functional imidazole-containing materials. Full article

In this study, 310S austenitic stainless-steel was welded using a laser with varying amounts of Nb to systematically investigate the effect of Nb on solidification cracking susceptibility, mechanical properties, and corrosion resistance of the weld. Under the present experimental conditions, the critical restraint width was higher for the 0.58 wt.% Nb and 1.45 wt.% Nb welds than for the Nb-free and 2.3 wt.% Nb welds, indicating that Nb addition affected the solidification cracking response of the weld. At low-to-moderate Nb contents, Nb can aggravate compositional segregation and increase the presence of low-melting-point liquid films, thereby increasing cracking susceptibility. At higher Nb contents, the reduced cracking susceptibility was accompanied by microstructural refinement and changes in the distribution of Nb-rich constituents during solidification. With increasing Nb content, the number of precipitated phases in the weld increases, mainly distributed at the austenite grain boundaries in granular, elongated, and chain-like forms. The introduction of Nb generally increases the microhardness and tensile strength of the welded joint, attributed to grain refinement strengthening and solid-solution strengthening. The reduction in area first increased and then decreased, suggesting that excessive Nb addition may reduce ductility because of the increased amount of grain-boundary precipitates and local strengthening heterogeneity. With increasing Nb content, the Ir/Ia ratio decreased from 67.6% to 52.2%, suggesting improved intergranular corrosion resistance. This improvement is likely related to the preferential reaction of Nb with carbon, which may suppress the formation of Cr-depleted zones at grain boundaries. Overall, Nb addition improved the corrosion resistance and increased the hardness and tensile strength of the weld; however, its effect on solidification cracking susceptibility was non-monotonic, indicating that careful control of Nb content is required to balance cracking susceptibility, mechanical properties, and corrosion resistance. Full article

Rising environmental concerns have intensified interest in waste valorisation and the development of sustainable, bio-based materials through green chemistry approaches. In this study, proteins extracted from waste lentil and chickpea seeds were used to develop protein-based films using a range of carboxylic acids as cross-linkers. The acids facilitated protein unfolding and promoted intermolecular interactions, allowing tunable control over mechanical strength, barrier performance, and water resistance. In addition to their structural role, the inherent bioactivity of selected carboxylic acids imparted added functionality to the resulting materials. Physical characterisation and FTIR secondary structure analysis revealed that the acid-type, plasticiser, and, in some cases, protein fraction composition influenced the final material performance. Liquid monocarboxylic acids produced cohesive and flexible films, with tensile strength ranging from ~1 to 23 MPa, with formic acid yielding the strongest films. Lactic acid and its blends improved flexibility and reduced permeability, achieving water vapour permeability (WVP) of 5.76 ± 0.7 × 10⁻¹² g m m⁻² s⁻¹ Pa⁻¹ and oxygen permeability (OP) of 5.8 ± 0.0 × 10⁻¹³ mL m m⁻² s⁻¹ Pa⁻¹ at low acid loadings. In contrast, solid di- and polycarboxylic acids tended to crystallise at higher concentrations. Citric acid was an exception, exhibiting behaviour distinct from the other solid acids and producing clear, crystal-free films with excellent flexibility, showing elongation at break (EAB) up to ~326%. Preliminary proof-of-concept application testing demonstrated the suitability of selected films for vegetable shelf-life extension for up to 17 days and for gradual lactic acid release, supporting their potential use as biodegradable cosmetic mask/patch platforms. Full article

This work focused on synthesizing MgSiO₃ (0%Mo@MgSi), 2.5%MoO3@MgSiO₃ (2.5%Mo@MgSi), 5%MoO₃@MgSiO₃ (5%Mo@MgSi), and 10%MoO₃@MgSiO₃ (10%Mo@MgSi) by a single-step process utilizing butylated hydroxytoluene (BYHT) as a novel capping agent. The X-ray diffraction analysis of the synthesized nanohybrids indicated amorphous nanohybrids, while the energy-dispersive X-ray spectroscopy results illustrated variations in the MoO₃ doping dosages. The 0%Mo@MgSi, 2.5%Mo@MgSi, 5%Mo@MgSi, and 10%Mo@MgSi nanohybrids exhibited average sizes of 17.6, 12.2, 11.7, and 9.9 nm, respectively, and surface areas of 43.53, 40.95, 42.17, and 44.98 m²·g⁻¹, respectively. The examination of 0%Mo@MgSi, 2.5%Mo@MgSi, 5%Mo@MgSi, and 10%Mo@MgSi nanohybrids toward the oxytetracycline (OTC) sorption resulted in q_t values of 72.89, 116.89, 98.39, and 78.46 mg·g⁻¹, respectively. The OTC sorption onto the 0%Mo@MgSi, 2.5%Mo@MgSi, 5%Mo@MgSi, and 10%Mo@MgSi aligned with the nonlinear pseudo-second order model, and both the intraparticle and liquid-film diffusion models co-influenced the OTC sorption onto the four nanohybrids. Increasing the temperature decreased OTC sorption on 2.5%Mo@MgSi, indicating exothermic sorption. The Langmuir isotherm model was more suitable than the Freundlich model for describing OTC adsorption on 2.5%Mo@MgSi. The Dubinin–Radushkevich energy (E_D ≤ 8.0 kJ·mol⁻¹) and the Gibbs free energy (ΔG° ≤ 20 kJ·mol⁻¹) supported each other’s outcomes about the OTC removal onto 2.5%Mo@MgSi being via physisorption. The ΔG° values increased proportionally with temperature, indicating that OTC sorption becomes more spontaneous as temperature decreases. Moreover, the 2.5%Mo@MgSi exhibited excellent stability in OTC elimination up to the third cycle. Full article

The rapid and precise detection of biomarkers and pathogens remains a critical challenge in clinical diagnostics. Traditional methodologies are frequently hindered by protracted workflows, complex sample preparation, and reliance on resource-intensive instrumentation. Acoustofluidics—the synergistic integration of acoustics and microfluidics—has emerged as a transformative solution for point-of-care testing (POCT). Bulk acoustic wave (BAW) and surface acoustic wave (SAW) technologies enable the contactless, label-free, and biocompatible manipulation of bioparticles across micro- and nanometer scales. This review critically examines recent advancements in BAW- and SAW-based acoustofluidic biosensors. We elucidate the fundamental principles governing distinct acoustic modes—including Quartz Crystal Microbalance (QCM), film bulk acoustic resonator (FBAR), and Solidly Mounted Resonator (SMR) for BAW and Rayleigh and Love waves for SAW—and evaluate their specific roles in liquid-phase sensing, particle sorting, and cellular focusing. Results show that integrating on-chip sample preparation accelerates diagnostic workflows, reducing assay times to under 10 min. Coupling acoustic manipulation with optical, mass-based, or electrochemical modalities effectively overcomes fundamental diffusion limits, achieving ultrasensitive, multimodal detection. We address translational challenges—acoustothermal heating, biofouling, and scalable integration. Following a discussion of clinical applications in oncology and infectious diseases, we map emerging trajectories, emphasizing AI-driven intelligent microfluidics, modular architectures, and flexible wearable platforms that will ultimately democratize continuous precision diagnostics. Full article