Search Results (1,324)

During the process of oil and gas drilling, due to the existence of pores or micro-cracks, drilling fluid is prone to invade the formation. Under the action of hydration expansion of clay in the formation and liquid pressure, wellbore instability occurs. In order to reduce the wellbore instability caused by drilling fluid intrusion into the formation, this study proposed a method of forming a dynamic hydrogen bond cross-linked network weak gel structure with modified nano-silica and P(AM-AAC). The plugging performance of the drilling fluid and the performance of inhibiting the hydration of shale were evaluated through various experimental methods. The results show that the gel composite system (GCS) effectively optimizes the plugging performance of drilling fluid. The 1% GCS can reduce the linear expansion rate of cuttings to 14.8% and increase the recovery rate of cuttings to 96.7%, and its hydration inhibition effect is better than that of KCl and polyamines. The dynamic cross-linked network structure can significantly increase the viscosity of drilling fluid. Meanwhile, by taking advantage of the liquid-phase viscosity effect and the physical blocking effect, the loss of drilling fluid can be significantly reduced. Mechanism studies conducted using zeta potential measurement, SEM analysis, contact angle measurement and capillary force assessment have shown that modified nano-silica stabilizes the wellbore by physically blocking the nano-pores of shale and changing the wettability of the shale surface from hydrophilic to hydrophobic when the contact angle exceeds 60°, thereby reducing capillary force and surface free energy. Meanwhile, the dynamic cross-linked network can reduce the seepage of free water into the formation, thereby significantly lowering the fluid loss of the drilling fluid. This research provides new insights into improving the stability of the wellbore in drilling fluids. Full article

Research on raw materials for Al₂O₃-SiC-C refractory castables used in blast furnace troughs is relatively well established. However, gaps remain in both laboratory and industrial trials concerning the performance of castables incorporating SiC-modified flake graphite and alternative carbon sources. This study investigated the sintering behavior, mechanical properties, and service performance of Al₂O₃-SiC-C castables utilizing varying contents of modified flake graphite, pitch, and carbon black as carbon sources. Samples were characterized using SEM, XRD, and EDS for phase composition and microstructural morphology analysis. Key findings revealed that the thermal expansion mismatch between the SiC coating and flake graphite in SiC-modified graphite generated a microcrack-toughening effect. This effect, combined with the synergistic reinforcement from both components, enhanced the mechanical properties. The SiC modification layer improved the wettability and oxidation resistance of the flake graphite. This modified graphite further contributed to enhanced erosion resistance through mechanisms of matrix pinning and crack deflection within the microstructure. However, the microcracks induced by thermal mismatch concurrently reduced erosion resistance, resulting in an overall limited net improvement in erosion resistance attributable to the modified graphite. Specimens containing 1 wt.% modified flake graphite exhibited the optimal overall performance. During industrial trials, this formulation unexpectedly demonstrated a water reduction mechanism requiring further investigation. Full article

Firstly, this paper reviews the fundamental theories of solid surface wettability and contact angle hysteresis. Subsequently, it further introduces four typical wettability-engineered surfaces with low hysteresis (superhydrophobic, superamphiphobic, super-slippery, and liquid-like smooth surfaces). Finally, it focuses on the latest research progress in the field of droplet manipulation on open planar surfaces with engineered wettability. To achieve droplet manipulation, the core driving forces primarily stem from natural forces guided by bioinspired gradient surfaces or the regulatory effects of external fields. In terms of bioinspired self-propelled droplet movement, this paper summarizes research inspired by natural organisms such as desert beetles, cacti, self-aligning floating seeds of emergent plants, or water-walking insects, which construct bioinspired special gradient surfaces to induce Laplace pressure differences or wettability gradients on both sides of droplets for droplet manipulation. Moreover, this paper further analyzes the mechanisms, advantages, and limitations of these self-propelled approaches, while summarizing the corresponding driving force sources and their theoretical formulas. For droplet manipulation under external fields, this paper elaborates on various external stimuli including electric fields, thermal fields, optical fields, acoustic fields, and magnetic fields. Among them, electric fields involve actuation mechanisms such as directly applied electrostatic forces and indirectly applied electrocapillary forces; thermal fields influence droplet motion through thermoresponsive wettability gradients and thermocapillary effects; optical fields cover multiple wavelengths including near-infrared, ultraviolet, and visible light; acoustic fields utilize horizontal and vertical acoustic radiation pressure or acoustic wave-induced acoustic streaming for droplet manipulation; the magnetic force acting on droplets may originate from their interior, surface, or external substrates. Based on these different transport principles, this paper comparatively analyzes the unique characteristics of droplet manipulation under the five external fields. Finally, this paper summarizes the current challenges and issues in the research of droplet manipulation on the open planar surfaces and provides an outlook on future development directions in this field. Full article

This study investigates the surface modification of Ti-6Al-4V alloy through the electrical discharge machining (EDM) process to improve its suitability for orthopedic and dental implant applications. The analysis focused on evaluating the morphological, wettability, roughness, hardness, and biocompatibility properties of the modified surfaces. Samples were subjected to different dielectric fluids and polarities during EDM. Subsequently, optical microscopy, roughness measurements, Vickers microhardness, contact angle tests, and in vitro cytotoxicity assays were performed. The results demonstrated that EDM processing led to the formation of distinct layers on the sample surfaces, with surface roughness increasing under negative polarity by up to ~304% in Ra and 305% in Rz. Additionally, wettability measurements indicated that the modified surfaces presented a lower water contact angle, which suggests enhanced hydrophilicity. Moreover, the modified samples showed a significant increase in Vickers microhardness, with the highest value reaching 1520 HV in the recast layer, indicating improvements in the mechanical properties. According to ISO 10993-5, all treated samples were classified as non-cytotoxic, presenting RGR values above 75%, similar to the untreated Ti-6Al-4V alloy. Therefore, it is concluded that surface modification through the EDM process has the potential to enhance the properties and safety of biomedical implants made with this alloy. Full article

The conservation and restoration of water-gilded wooden cultural heritage, such as polychrome sculptures, frames, panels, altarpieces, etc., requires the use of fillers that guarantee structural stability, physicochemical and mechanical compatibility with the original support, and the ability to adapt to dimensional movements induced by thermo-hygrometric variations. This study, conducted as part of the DorART Project, analyzed the behavior of nine formulations, both commercial and non-commercial, selected through a review of the state-of-the-art specialized literature, along with the use of participatory science, which focused on the practices and materials most commonly used by professionals in the field. The experimental design was based on three types of specimens: two with wooden supports, selected for evaluating their interaction with the original material and with the traditional water gilding technique, and a third type for analyzing the individual behavior of the tested materials. Analyses of adhesion, tensile strength, Shore C hardness, gloss, abrasion test results, wettability, pH changes, and chemical composition were performed using ATR-FTIR spectroscopy. The results showed significant differences depending on the type of curing used and the composition and aging behavior of the specimen. Some of the fillers demonstrated improved compatibility with water-based gilding, facilitating workability and providing structural strength. M3 and M9 demonstrated an optimal balance of workability and aging stability. The results of this study can help restorers select materials based on their specific needs, considering the requirements of mechanical adaptation to the substrate, compatibility, and durability. Full article

This study employed sodium laurate solution as the raw material to fabricate superhydrophobic coatings on cement-based substrates via a facile one-step spraying method. To optimize the processing parameters, the influence of solution concentration on substrate wettability was investigated, leading to the identification of the optimal concentration. Subsequently, superhydrophobic coatings were fabricated under these optimized conditions, and their wettability, mechanical durability, chemical corrosion resistance, and surface repairability were systematically characterized. The results revealed that the coating fabricated with a 0.3% sodium laurate solution exhibited an obvious regular, flaky, rough microstructure, achieving a water contact angle (WCA) of 154° ± 2° and a sliding angle (SA) of 2.9°. The coating demonstrated superhydrophobicity (WCA > 150° and SA < 10°), self-cleaning capability, mechanical durability, chemical corrosion resistance, and environmental stability; furthermore, the abraded surface can be restored to be superhydrophobic by simple and rapid repair. Full article

Sustainable deepwater drilling for oil and gas offers significant potential. In this work, we synthesized a nanoscale collapse-prevention agent by grafting didecyldimethylammonium chloride onto spherical nano-silica and characterized it using Fourier-transform infrared spectroscopy, thermogravimetric analysis, zeta-potential, and particle-size measurements, as well as SEM and TEM. Adding 1 wt% of this agent to a bentonite slurry only marginally alters its rheology and maintains acceptable low-temperature flow properties. Microporous-membrane tests show filtrate passing through 200 nm pores drops to 55 mL, demonstrating excellent plugging. Core-immersion studies reveal that shale cores retain integrity with minimal spalling after prolonged exposure. Rolling recovery assays increase shale-cutting recovery to 68%. Wettability tests indicate the water contact angle rises from 17.1° to 90.1°, and capillary rise height falls by roughly 50%, reversing suction to repulsion. Together, these findings support a synergistic plugging–adsorption–hydrophobization mechanism that significantly enhances wellbore stability without compromising low-temperature rheology. This work may guide the design of high-performance collapse-prevention additives for safe, efficient deepwater drilling. Full article

Goat milk has lower allergenicity and high commercial value but faces storage limitations, often leading to waste. Converting it into powder increases costs, making blending with non-dairy ingredients, such as rice flour, a viable alternative to reduce costs and potentially improve nutrition. In this this study, we developed five dairy compounds by replacing 10–49% of goat milk powder with rice flour. We evaluated their nutritional and physical properties compared to pure goat milk powder and rice flour. Analyses included water activity, total solids, protein, lipids, energy value, color, flowability, wettability, polyphenol content, mineral profile, and morphology. Higher rice flour content increased water activity and improved wettability but reduced flowability, classifying most compounds as reasonable to fair in flow, except for the 10% rice flour sample. All samples met Brazilian standards, which require ≥13 g/100 g of protein. The dairy compounds showed a yellow-greenish color, with significant color differences compared to goat milk powder, particularly at 49% rice flour. Goat milk powder had higher mineral contents (Ca, K, Mg, Na, P, Zn). Total polyphenol content was highest in the 10% rice flour compound, while individual polyphenols were undetectable. Overall, the formulation proved viable for cost reduction while maintaining nutritional quality. Full article

Prostate cancer is a serious, life-threatening condition among men, usually requiring long-term chemotherapy. Due to its high efficacy, bicalutamide, a non-steroidal anti-androgen, has widespread use. However, its poor water solubility, low oral bioavailability, and nonspecific systemic exposure limit its application. To overcome these obstacles, our study explored the potential of non-carboxylated and carboxylated mesoporous carbon nanoparticles (MCN) as advanced drug carriers for bicalutamide (MCN/B and MCN-COOH/B). The physicochemical properties and release behaviour were thoroughly characterized. Functionalization with carboxylic groups significantly improved wettability, dispersion stability, as well as loading efficiency due to enhanced hydrogen bonding and π–π stacking interactions. Moreover, all systems exhibited sustained and near-infrared (NIR) triggered drug release with reduced burst-effect, compared to the release of free bicalutamide. Higher particle size and stronger drug–carrier interactions determined a zero-order kinetics and notably slower release rate of MCN-COOH/B compared to non-functionalized MCN. Cytotoxicity assays on LNCaP prostate cancer cells demonstrated that both MCN/B and MCN-COOH/B possessed comparable antiproliferative activity as free bicalutamide, where MCN-COOH/B exhibited superior efficacy, especially under NIR exposure. These findings suggest that MCN-COOH nanoparticles could be considered as a prospective platform for controlled, NIR-accelerated delivery of bicalutamide in prostate cancer treatment. Full article

The sapwood and heartwood of European larch (Larix decidua Mill.) are both used in industrial applications, but they differ in structure and composition, which may lead to surface property differences. This study compared their surface characteristics (on radial and tangential sections) after sanding with aluminium oxide papers of four grit sizes (P60, P120, P180, P240). Surface roughness (Ra, Rz), wettability (contact angle with two reference liquids: water and diiodomethane, 3 and 30 s after droplet deposition), surface free energy, and colour parameters (L*, a*, b*) were analysed. Microscopic measurements were also performed to assess anatomical differences between sapwood and heartwood. The results showed no significant differences in roughness (Ra, Rz) between sapwood and heartwood. Measurement direction and sandpaper grit accounted for about 80% of variability in roughness parameters. Wettability was mainly influenced by wood area, with its effect ranging from 55% to 89% depending on measurement time. The sapwood was characterised by the lower wettability on the tangential section, while the heartwood was characterised by the lower wettability on the radial section. This was examined for the contact angle tests performed 3 s after the water droplet had been applied to the wood surface. Such dependencies were not observed after 30 s. Sapwood exhibited higher surface free energy (SFE) values than heartwood. The greatest colour change ΔE, at level 2.59, was noted for the heartwood on the radial section after sanding with P240 sandpaper. Full article

Due to the complex mineral composition, low clay content, and strong heterogeneity of the mixed sedimentary shale in the Xinjiang Salt Lake Basin, the wettability characteristics of the reservoir and their influencing factors are not yet clear, which restricts the evaluation of oil-bearing properties and the identification of sweet spots. This paper analyzed mixed sedimentary shale samples from the Lucaogou Formation of the Jimsar Sag and the Fengcheng Formation of the Mahu Sag. Methods such as petrographic thin sections, X-ray diffraction, organic matter content analysis, and argon ion polishing scanning electron microscopy were used to examine the lithological and mineralogical characteristics, geochemical characteristics, and pore space characteristics of the mixed sedimentary shale reservoir. Alternating imbibition and nuclear magnetic resonance were employed to quantitatively characterize the wettability of the reservoir and to discuss the effects of compositional factors, lamina types, and pore structure on wettability. Research findings indicate that the total porosity, measured by the alternate imbibition method, reached 72% of the core porosity volume, confirming the effectiveness of alternate imbibition in filling open pores. The Lucaogou Formation exhibits moderate to strong oil-wet wettability, with oil-wet pores predominating and well-developed storage spaces; the Fengcheng Formation has a wide range of wettability, with a higher proportion of mixed-wet pores, strong heterogeneity, and weaker oil-wet properties compared to the Lucaogou Formation. TOC content has a two-segment relationship with wettability, where oil-wet properties increase with TOC content at low TOC levels, while at high TOC levels, the influence of minerals such as carbonates dominates; carbonate content shows an “L” type response to wettability, enhancing oil-wet properties at low levels (<20%), but reducing it due to the continuous weakening effect of minerals when excessive. Lamina types in the Fengcheng Formation significantly affect wettability differentiation, with carbonate-shale laminae dominating oil pores, siliceous laminae contributing to water pores, and carbonate–feldspathic laminae forming mixed pores; the Lucaogou Formation lacks significant laminae, and wettability is controlled by the synergistic effects of minerals, organic matter, and pore structure. Increased porosity strengthens oil-wet properties, with micropores promoting oil adsorption through their high specific surface area, while macropores dominate in terms of storage capacity. Wettability is the result of the synergistic effects of multiple factors, including TOC, minerals, lamina types, and pore structure. Based on the characteristic that oil-wet pores account for up to 74% in shale reservoirs (mixed-wet 12%, water-wet 14%), a wettability-targeted regulation strategy is implemented during actual shale development. Surfactants are used to modify oil-wet pores, while the natural state of water-wet and mixed-wet pores is maintained to avoid interference and preserve spontaneous imbibition advantages. The soaking period is thus compressed from 30 days to 3–5 days, thereby enhancing matrix displacement efficiency. Full article

Silicon nitride (Si₃N₄) ceramic is widely used in the production of structural components. The surface wettability is closely related to the service life of materials. Laser surface texturing is considered an effective method for controlling surface wettability by processing specific patterns. This research focused on the laser surface texturing of a Si₃N₄ ceramic, employing rectangular patterns instead of the typical dimple designs, as these had promising applications in heat transfer and hydrodynamic lubrication. The effects of scanning speed and number of scans on the change of the morphologies and dimensions of the grooves were investigated. The results indicated that the higher scanning speed and fewer number of scans resulted in less damage to the textured surface. As the scanning speed increased, the width and depth of the grooves decreased significantly first, and then fluctuated. Conversely, increasing the number of scans led to an increase in the width and depth of the grooves, eventually stabilizing. The analysis of the elemental composition of different areas on the textured surface presented a notable increase in oxygen content at the grooves, while Si and N levels decreased. It was mainly caused by the chemical reaction between Si₃N₄ ceramic and oxygen during laser surface texturing in an air environment. This study also assessed the wettability of the textured surface, finding that the contact angle of the water droplet was significantly affected by the groove dimensions. After laser surface texturing, the contact angle increased from 35.51 ± 0.33° to 57.52 ± 1.83°. Improved wettability was associated with smaller groove volume, indicating better hydrophilicity at lower scanning speed and enhanced hydrophobicity with a fewer number of scans. Full article

Membrane distillation (MD) has attracted increasing attention as a thermally driven separation process for water purification, desalination, and wastewater treatment. Its primary advantages include high rejection of non-volatile solutes, compatibility with low-grade or waste heat sources, and operation at ambient pressure. Despite these benefits, large-scale implementation remains limited due to the lack of membrane materials capable of withstanding harsh operating conditions and maintaining their hydrophobic character. Polymeric membranes have traditionally been used in MD applications; however, their limited thermal and chemical stability compromises long-term performance and reliability. In contrast, ceramic membranes are emerging as a promising alternative, offering superior mechanical strength, chemical resistance, and thermal stability. Nevertheless, their broader adoption in MD is hindered by several challenges, including high thermal conductivity, surface wettability, high fabrication costs, and limited scalability. This review provides a critical assessment of current developments, key opportunities, and ongoing challenges associated with the use of ceramic membranes in MD. Particular emphasis is placed on advances in surface modification techniques and the emerging applications in advanced MD configurations. Full article

A superhydrophobic surface with hierarchical micro/nano-array structures was successfully fabricated on 6061 aluminum alloy through a combination of femtosecond laser etching and anodic oxidation. Femtosecond laser etching formed a regularly arranged microscale “pit-protrusion” array on the aluminum alloy surface. After modification with a fluorosilane ethanol solution, the surface exhibited superhydrophobicity with a contact angle of 154°. Subsequently, the anodic oxidation process formed an anodic oxide film dominated by an array of aluminum oxide (Al₂O₃) nanopores at the submicron scale. Scanning electron microscopy (SEM) and X-ray diffraction (XRD) analyses revealed that the nanopore structures uniformly and continuously covered the laser-ablated layer. This hierarchical structure significantly increased the surface water contact angle to 162°. Wettability analysis showed that the prepared composite coating formed an air layer accounting for 91% of the surface area. Compared with the sample only treated by femtosecond laser etching, the presence of the Al₂O₃ nanopore structure significantly enhanced the mechanical durability, superhydrophobic durability, and corrosion resistance of the superhydrophobic surface. The proposed multi-step fabrication strategy offers an innovative method for creating multifunctional, durable superhydrophobic coatings and has important implications for their large-scale industrial use. Full article

Water within coal reservoirs exerts dual effects on methane adsorption–desorption by competing for adsorption sites and reducing permeability. The bound water effect, caused by coal wettability, significantly constrains coalbed methane (CBM) production, rendering investigations into coal wettability crucial for efficient CBM development. Compared with other geological formations, coals are characterized by a highly developed microporous structure, making the CO₂ sequestration mechanism in coal seams closely linked to the microscale interactions among gas, water, and coal matrixes. However, the intrinsic mechanisms remain poorly understood. In this study, molecular dynamics simulations are employed to investigate the wettability behaviors of CO₂, CH₄, and water on different coal matrix surfaces under varying temperature and pressure conditions, for coal macromolecules representative of four coal ranks. The study reveals the evolution of water wettability in response to CO₂ and CH₄ injection, identifies wettability differences among coal ranks, and analyzes the microscopic mechanisms governing wettability. The results show the following: (1) The contact angle increases with gas pressure, and the variation in wettability is more pronounced in CO₂ environments than in CH₄. As pressure increases, the number of hydrogen bonds decreases, while the peak gas density of CH₄ and CO₂ increases, leading to larger contact angles. (2) Simulations under different temperatures for the four coal ranks indicate that temperature has minimal influence on low-rank Hegu coal, whereas for higher-rank coals, gas adsorption on the coal surface increases, resulting in reduced wettability. Interfacial tension analysis further suggests that higher temperatures reduce water surface tension, cause dispersion of water molecules, and consequently improve wettability. Understanding the wettability variations among different coal ranks under variable pressure–temperature conditions provides a fundamental model and theoretical basis for investigating deep coal seam gas–water interactions and CO₂ geological sequestration mechanisms. These findings have significant implications for the advancement of CO₂-ECBM technology. Full article