Search Results (1,116)

The development of bioactive hybrid coatings for biomedical implants requires materials exhibiting suitable thermal stability, bioactivity, and biocompatibility. In this study, hybrid organic–inorganic sol–gel coatings based on silica (SiO₂) and polyethylene glycol (PEG, 24 wt%) were functionalized with different concentrations of caffeic acid (CafA 5, 10, and 15 wt%) and deposited onto AISI 304 and AISI 316 stainless steel substrates by dip-coating without surface pre-treatment. The proposed approach enabled the formation of homogeneous hybrid coatings on untreated stainless steel substrates through a simple and scalable deposition process. A thermal analysis demonstrated the stability of the hybrid network and the effective integration of the organic and inorganic phases. Bioactivity was evaluated by in vitro immersion in simulated body fluid (SBF), while SEM observations revealed the formation of mineral deposits on the coating surface, and an EDX analysis confirmed the presence of calcium and phosphorus within the deposited layer. The formation of crystalline hydroxyapatite (HA) was subsequently confirmed by X-ray diffraction (XRD), confirming that all investigated formulations retained their ability to induce apatite formation after SBF immersion. In addition, in vitro biocompatibility assays confirmed that the developed materials exhibited concentration-dependent cytocompatibility, with the cellular response being influenced by the amount of incorporated CafA. Overall, the results demonstrate that the proposed hybrid materials combine thermal stability, bioactivity, and cytocompatibility, highlighting their potential as bioactive coatings for biomedical applications. Full article

To further enhance the application effectiveness and energy efficiency of dielectric barrier discharge plasma coupled with catalytic technology, this study investigates the synergistic effect between coated catalysts and dielectric barrier discharge. A two-dimensional fluid model was established, and numerical simulations were conducted using the finite element method to evaluate NO removal from automobile exhaust gases. Results show that, compared to dielectric barrier discharge alone, the degradation efficiency of low-concentration NO increases by 6%–29% when a coated catalyst is introduced. Three coated catalysts, including Mn/TiO₂/γ-Al₂O₃, Mn/γ-Al₂O₃ and TiO₂, are compared for 1% NO treatment, whose degradation efficiencies are 63.1%, 53.7% and 40.2%, respectively. As the NO concentration increased from 1% to 3%, the degradation efficiency of all three catalysts decreased. In terms of NO₂ by-product generation, the synergistic system with Mn/TiO₂/γ-Al₂O₃ produces the least NO₂. This coupling technology effectively removes low-concentration nitrogen oxides from vehicle exhaust, enriches plasma-catalysis theory, and supports global efforts in controlling motor vehicle emissions pollution. 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

Rapid corrosion and poor coating adhesion continue to limit the use of magnesium alloys as temporary orthopedic implants. The two-stage laser process was developed to separate the high-temperature melting of 45S5 bioactive glass (BG) from the low-melting-point AZ31 substrate. Femtosecond-laser grids with spacings of 100, 200, and 300 μm were first produced on AZ31 to provide anchoring sites. Then, the target 45S5 BG was suspended above the substrate, locally melted with CO₂ laser, and transported onto the textured surface by gas jet. The 200 μm grid texture for Mg substrate with lowest water contact angle could give the highest tape-test adhesion rating (4B). At the selected deposition conditions of 20 W and 20 L·min⁻¹, two coating cycles produced a continuous layer approximately 50.5 μm thick. Relative to bare Mg alloy, this double-layer coating increased polarization resistance from 1.20 × 103 to 1.39 × 10⁵ Ω·cm² and decreased corrosion current density from 8.70 × 10⁻⁴ to 5.33 × 10⁻⁶ A·cm⁻². It also limited alkalization and mass loss during 28 days in simulated body fluid. As such, the double-layer surface coating supported apatite formation and improved MC3T3-E1 proliferation and alkaline phosphatase activity. These findings indicated that suspended-target deposition was able to form adherent, bioactive glass coatings on magnesium while limiting direct thermal damage to the substrate. Full article

Centrifugal atomization is used to generate droplets or particles in processes ranging from crop protection and metallurgical powder production to rotary-bell coating, combustion, and spray-based product processing. However, comparison across studies is hindered by differences in atomizer geometry, characteristic scales, fluid properties, operating windows, diagnostic methods, and performance metrics. This article presents a structured critical review of centrifugal atomization mechanisms, investigation methods, and multidisciplinary applications. The literature is organized according to operational definitions, atomizer configuration, liquid-film evolution, primary and secondary breakup, experimental and numerical approaches, and application-level performance. Rather than assuming universal phase boundaries, the review synthesizes reported transition criteria for direct-drop, ligament, and film breakup and examines their dependence on geometry, liquid throughput, rotational speed, fluid rheology, surface tension, and surrounding-gas conditions. Across applications, the available evidence indicates that rotational speed and liquid throughput strongly affect film thickness and breakup intensity, but their influence on droplet or particle size remains conditional on the prevailing regime and device geometry. The review further compares the strengths, limitations, validation status, and transferability of commonly used experimental and computational methods. Remaining priorities include standardized definitions of characteristic scales, matched-condition comparisons, uncertainty reporting, benchmark datasets for multiphysics models, and testable criteria for scale-up and cross-application transfer. Full article

Hybrid structural materials (HSMs), such as nanoparticle-treated fabrics, have been shown to enhance acoustic and ballistic performance in multifunctional protective structures. They offer a promising means for low-frequency (<~1000 Hz) noise mitigation, which remains a critical challenge in aerospace and defense applications. The measurement and modeling of their sound transmission loss (TL) behavior using a coupled acoustic–poroelastic approach is explored in this study. A colloid-based soaking and drying process is used to impregnate nanoparticles into the fabric. Previous studies using SEM imaging have established that at low (<~20 wt.%) treatment levels, the nanoparticles agglomerate in the interstitial spaces between yarn crossover points, whereas at higher levels, they begin to coat the yarn bundle tops. TL was measured experimentally using normal-incidence impedance tube tests. Further, parameters such as static flow resistivity, porosity, flexural modulus, and density required to model the neat and treat samples as fluid-filled porous solids using the Biot–Allard model were obtained from experiments for a limited set of neat and treated cases. Static flow resistivity was measured using an air permeability tester as per ISO 9237, and a modified version of the Peirce’s cantilever beam test was used to obtain the flexural modulus for neat and treated samples. Porosity was estimated using digital image analytics. The poroelastic fabric model was implemented in finite element simulations, and the predicted TL was compared with experiments including those for uncalibrated treated cases. The model shows close alignment with measured TL at low frequencies (<~600 Hz) for all cases but deviates closer towards the theoretical mass law at higher frequencies, where flanking effects and the influence of the hierarchy of pores are expected to be dominant in experiments. Further studies are underway to incorporate such higher-order effects to improve predictions at higher frequencies. The development of this model provides a means to capture the influence of nanoparticle addition on the acoustic performance of Kevlar, enabling fast and efficient virtual design iterations. The approach helps optimize HSMs for noise mitigation in multifunctional applications for the aerospace, defense, and infrastructural sectors. Full article

Turbidite sandstones of the Chang 6 member and delta-front sandstones of the Chang 8 member in the Yuele Block, southwestern Yishan Slope, Ordos Basin, serve as the primary tight oil reservoirs. In this study, a total of 243 continuous core samples from multiple wells were collected for integrated analyses, including cast thin-section observation, scanning electron microscopy (SEM), X-ray diffraction (XRD) of clay minerals, routine core physical property measurements and mercury intrusion porosimetry (MIP), to systematically compare sedimentary–diagenetic disparities between semi-deep lacustrine turbidites (Chang 6) and delta-front sandstones (Chang 8). Measured data indicate that the two intervals have similar average porosities of 9.27% and 9.88%, while their respective geometric mean permeabilities differ markedly, with values of only 0.142 × 10⁻³ μm² for Chang 6 and 0.260 × 10⁻³ μm² for Chang 8. Micro-pore-throat size and connectivity dominate reservoir fluid flow capacity, and total porosity alone cannot objectively evaluate reservoir quality. Delta-front sandstones of the Chang 8 member are supplied by a proximal magmatic-rich provenance from the southwest, and widespread grain-coating chlorite forms during early diagenesis, effectively mitigating compaction damage and inhibiting quartz overgrowth, leading to well-preserved primary pores. As mixed-provenance deposits lacking protective chlorite rims, Chang 6 turbidites experience more intensive compaction, and abundant fibrous illite and carbonate cements precipitate in the subsequent diagenetic stage to fill and separate pore throats, forming an isolated micropore network. Quantitative comparison with baseline parameters of the Longdong region reveals that the Yuele Block is located closer to the southwestern sediment source, resulting in higher contents of magmatic lithics and chlorite in Chang 8 as well as elevated illite concentrations in Chang 6 relative to regional averages, which verifies that source-to-sink transport distance regulates reservoir quality by driving the differentiation of clay mineral assemblages. A complete quantitative coupling sequence of “provenance supply–authigenic clay mineral-pore evolution” is defined herein, and two distinct sedimentary–diagenetic evolutionary routes are classified: high-quality delta-front reservoirs protected by grain-coating chlorite, and low-quality turbidite reservoirs blocked by illite–carbonate cements. This research refines the diagenetic differentiation rules for continental tight sandstones with diverse sedimentary origins in the Ordos Basin and provides quantitative mineralogical criteria for identifying tight oil sweet spots in proximal provenance blocks. Full article

Frankincense, a natural resin obtained from Boswellia species, has been extensively utilized in traditional medicine and has attracted significant attention in biomedical applications owing to its vast therapeutic effects. While many studies and reviews have reported its pharmacological and biomedical applications, its potential in broader engineering domains and material science remains less explored. In biomedical engineering, frankincense-based compounds have been successfully incorporated into several matrices including hydrogels, nanomaterials, scaffolds, coatings for tissue engineering, food preservation and functional textiles. Frankincense has also exhibited significant potential as a functional component in engineering materials and environmental applications including its significant effects as a green corrosion inhibitor, drilling-fluid modifier and adsorbent materials. This review also highlights the economic aspects of frankincense utilization by evaluating and comparing its production, market value and scalability with other natural resin and gums. Additionally, environmental and sustainability factors associated with frankincense production, harvesting practices and resource availability have also been discussed. Overall, this review provides an overview of frankincense’s potential in diverse engineering applications and highlights the transition of frankincense from a traditional medicinal resin to a promising bio-based material for biomedical, material and environmental engineering applications. Full article

The large aspect ratio micro end mill is a critical tool for microstructure machining, and its performance directly determines processing quality and efficiency. Diamond coatings are commonly applied to cutting edges to enhance wear resistance and extend tool life. However, existing coating techniques often suffer from poor uniformity and inadequate consistency, limiting batch production and process stability. Aerosol jet printing (AJP) offers a cost-effective and highly controllable alternative for the efficient, large-scale deposition of diamond coatings on micro end mills, where precise control of line spacing is essential to achieving coating uniformity. In this study, a transient numerical model of droplet deposition in AJP is developed using computational fluid dynamics (CFD). The volume of fluid (VOF) method and the discrete phase model (DPM) are coupled to track liquid–gas interface deformation and diamond particle motion, enabling the dynamic evolution of droplet deposition to be captured. The effects of inter-droplet distance on deposition, spreading, coalescence, and line uniformity are systematically investigated. Droplet deposition mechanisms are analyzed under low-speed jetting conditions, while high-speed jetting simulations are conducted to reflect industrial processing scenarios. The results show that under low-speed jetting, droplets undergo spreading, contraction, and rebound, eventually forming a uniform cap-like structure. Under high-speed jetting, droplets exhibit a dispersed ring-shaped spreading pattern; although uniformity is slightly reduced, the spreading area and deposition efficiency are significantly increased. These findings provide a theoretical basis for optimizing AJP process parameters to achieve high-quality diamond coatings on micro end mills. Full article

Background/Objectives: Mpox (formerly monkeypox) is a re-emerging global health threat. While current vaccines are injectable, oral vaccination offers a painless alternative, though the harsh gastrointestinal (GI) environment challenges live viral vaccines. This study evaluated the stability of orthopoxviruses under simulated GI conditions to assess the physicochemical feasibility of oral mpox immunization. Methods: Attenuated and virulent strains of vaccinia, cowpox, and camelpox viruses were exposed to simulated gastric (pH 1.0–2.0 and 3.0–4.0 with pepsin) and intestinal (pH 7.0–7.5) conditions at 37 °C for 180 min. Viral titers were determined via cell culture assays. The physicochemical protective efficacy of enteric-coated capsules was evaluated using standard dissolution testing parameters. Results: All orthopoxviruses were rapidly inactivated under highly acidic fasting conditions (pH 1.0–2.0). However, they exhibited high stability at pH 3.0–4.0 and 7.0–7.5, retaining approximately 20–30% of their initial infectivity after 180 min. Enteric-coated capsules successfully maintained shell integrity in simulated gastric fluids for over 3 h and dissolved completely under intestinal conditions within ~130 min, aligning with small intestine transit times. Conclusions: Orthopoxviruses possess sufficient intestinal stability to support the physicochemical feasibility of oral immunization, provided they are protected from gastric acidity. Enteric-coated capsules represent a highly suitable delivery system for the intestinal release of live orthopoxvirus-based candidates, warranting further in vivo preclinical evaluation. Full article

Magnesium alloys are promising candidates for biomedical implants, but their rapid corrosion limits clinical use. Simulated body fluid (SBF) is commonly used to evaluate corrosion behaviour; however, Ca-P and carbonate deposits can mask the intrinsic performance of protective coatings. Tris(hydroxymethyl)aminomethane (Tris) has been proposed as an SBF modifier, although its effect on coated magnesium remains poorly understood. While Tris modifies the buffering characteristics of the solution, it also alters the stability of Mg(OH)₂ and the precipitation equilibria of corrosion products, resulting in more aggressive corrosion conditions than standard SBF. Here, the corrosion behaviour of AZ31 alloy, a plasma electrolytic oxidation (PEO) coating, and a sol-gel sealed PEO coating was investigated in SBF with and without Tris. Electrochemical impedance spectroscopy, immersion tests, pH monitoring, and post-immersion SEM/EDS analyses were used to evaluate coating performance under physiological and aggressive conditions. The results show that AZ31 and PEO coatings exhibit higher apparent corrosion resistance in SBF without Tris due to corrosion-product stabilization and Ca-P-rich deposits that partially block electrolyte access. In contrast, SBF with Tris accelerates degradation, causing uniform corrosion of AZ31 and premature PEO failure through electrolyte penetration and coating cracking. The PEO-AR/ZTP system maintains the highest electrochemical resistance and the best protective performance in both media. Full article

During ultra-deep well drilling, the bottomhole circulating temperature (BHCT) can easily exceed 150 °C, causing a series of problems such as drilling-fluid degradation, downhole instrument failure, and intensified well-control risks. Conventional surface-cooling methods experience sharply diminishing effectiveness under deep well conditions, while an insulated drill-pipe (IDP) offers good engineering feasibility as a passive cooling technique. However, existing studies lack a transient wellbore-formation coupled model validated by field data, and the influence patterns and interaction mechanisms of key parameters of the insulation coating under varying well depths remain unclear. Therefore, this study integrates a thermal-resistance representation into a transient wellbore-formation heat-transfer framework to characterize the insulation effect via an overall heat-transfer coefficient. Based on this framework, the cooling mechanism is systematically investigated from two perspectives: heat-absorption rate and cumulative blocked heat. Based on this model, the cooling mechanism is systematically investigated from two perspectives: heat-absorption rate and cumulative blocked heat. The results show that a 2000 m IDP section reduces BHCT from 161.81 °C (with a conventional drill-pipe, CDP) to 144.15 °C after 50 h of circulation. This yields an additional cooling of 17.66 °C and a cumulative blocked heat of 180.03 GJ. Parameter analysis further shows that lower thermal conductivity, longer coating length, and placement 200–400 m above the bottomhole enhance cooling, whereas coating thickness exhibits a marginal benefit threshold of 1 mm. More importantly, Sobol’ global sensitivity analysis reveals a distinct evolution of the dominant parameter controls with increasing well depth: at 6000 m measured depth (MD), coating length is the absolute governing factor; at 8000 m, coating position and length become equally important; at 10,000 m, the coupling between thermal conductivity and length emerges as critical; and at 12,000 m, thermal conductivity, thickness, position, and length jointly determine the cooling performance. This evolutionary pattern provides a depth-dependent priority framework for IDP parameter design, offering clear guidance for engineering application across varying well depths. Full article

Solar-Driven Photothermal Membrane Distillation (SPMD) integrates solar energy using photothermal coatings on the hydrophobic membranes, such as carbon black nanoparticles coated on PVDF membranes, to achieve localized heating at the liquid–vapor interface. This approach enhances energy efficiency by mitigating temperature polarization and reducing thermal energy demands compared to conventional membrane distillation (MD). However, the challenges of fouling and scaling, which can significantly impair membrane performance, continue to be a serious concern, similar to other MD configurations. This comprehensive review establishes a unified framework connecting core transmembrane mass and heat transfer mechanisms with the thermodynamic pathways of surface fouling and scaling. We critically evaluate various strategies for mitigating scaling and fouling, including the development of omniphobic membranes, the introduction of nano/micro bubbles, the addition of anti-scalants and surfactants, and the implementation of chemical and mechanical pretreatments. Subsequently, the impact of photothermal coatings, applied to the feed–membrane interface in SPMD to absorb solar radiation, on scaling and fouling resistance is also discussed. Finally, we provide a comprehensive review of advanced computational paradigms, for both coupled radiative-thermal and dynamic fouling models—contrasting deterministic, physics-based multi-phase Computational Fluid Dynamics (CFD) with empirical Response Surface Methodology (RSM) and predictive Artificial Intelligence (AI) data-driven models. Beyond this survey, we identify and directly address a critical, previously unquantified gap in the field of SPMD: the absence of an explicit thermodynamic link between transmembrane heat/mass transfer and the nucleation and adhesion processes that govern scaling and fouling, and we further highlight the practical barriers—photothermal coating durability, economic feasibility, and technology readiness—that currently separate laboratory-scale SPMD from field deployment. This holistic synthesis charts future engineering strategies for scalable, fouling-resistant, and optimized solar-driven desalination infrastructure. Full article

The oral cavity represents one of the most demanding operating environments for biomedical coatings, subjecting materials to constant masticatory shear and tribological stress, dynamic temperature fluctuations, salivary enzymatic activity, and continuous fluid turnover that collectively challenge coating adhesion, durability, and longevity. Thermosensitive hydrogels that undergo reversible sol–gel transitions near body temperature offer a uniquely versatile platform for in situ coating formation on complex oral surfaces, enabling minimally invasive application and conformal coverage of irregular anatomical structures—from periodontal pockets and root canal systems to extraction sockets and bone defects. This review examines the application of thermo-sensitive hydrogel coatings across six major oral disease categories: periodontitis, peri-implantitis, bone defects, endodontic diseases, extraction wounds, and oral cancer. We further discuss practical hurdles facing clinical translation, noting that sterilization often degrades these materials, mechanical properties may prove inadequate under masticatory loads, and long-term biosafety data remains limited. This review critically evaluates how these smart coatings can bridge the gap between laboratory innovation and clinical application, offering insights to guide the development of next-generation precision therapies for oral diseases. Full article

Implant-associated infections remain one of the leading causes of failure in orthopaedic and dental implants, necessitating the development of multifunctional surface coatings capable of simultaneously enhancing corrosion resistance, bioactivity, and antibacterial performance. The aim of this study was to investigate how picosecond laser surface treatment modifies the structural, physicochemical, mechanical, electrochemical, bioactive, and antibacterial properties of magnetron-sputtered TiO₂/CuO coatings on Ti6Al4V alloy. Structural characterisation revealed that laser treatment transformed the predominantly amorphous TiO₂ matrix into a more crystalline rutile-containing structure while preserving the CuO phase. The laser surface-treated (LST) surface exhibited increased surface hydroxylation, enhanced wettability, and a slightly higher release of Cu ions. In addition to modifying the surface chemistry, laser treatment improved the mechanical characteristics of the coating, contributing to its overall durability and suitability for biomedical implant environments. Electrochemical impedance spectroscopy demonstrated that both coatings significantly improved the corrosion resistance of Ti6Al4V in simulated body fluid, whereas the laser-treated coating showed superior long-term stability and passive layer evolution. Following immersion, both surfaces promoted the formation of Ca–P-rich hydroxyapatite deposits, indicating favourable bioactivity. Antibacterial testing against Staphylococcus aureus revealed reductions in bacterial viability of 67% and 74% for the AD and LST coatings, respectively. The enhanced antibacterial performance of the laser-treated surface was attributed to the combined effects of increased crystallinity, surface hydroxylation, hydrophilicity, and copper ion release. The novelty of this work lies in demonstrating that picosecond laser post-treatment can simultaneously tailor the crystallinity, surface chemistry, morphology, corrosion resistance, bioactivity, and antibacterial performance of magnetron-sputtered TiO₂/CuO coatings without compromising coating integrity, thereby providing a promising multifunctional surface modification strategy for biomedical implants. Full article