Search Results (5,550)

Stone heritage deteriorates through physical, chemical, and biological processes driven by water, climate, and microbial colonization. Multifunctional polymeric coatings combining hydrophobic and antimicrobial moieties have emerged as a promising conservation strategy, yet a substantial gap remains between laboratory innovation and real-world performance. This review critically examines advances from 2021 to 2026, covering wetting theory, antimicrobial mechanisms, and material architectures, including molecularly integrated systems, Sol–Gel hybrids, nanocomposites, and layered systems. Long-term studies on the Aurelian Walls in Rome and stone in Reims show that biocidal efficacy typically declines within one to two years despite the chemical persistence of the coatings. In parallel, hydrophobic performance often deteriorates over time due to UV exposure, particulate deposition, and surface chemical changes, leading to increased wettability and reduced protective efficiency. Substrate porosity governs durability and visual compatibility (ΔE* < 5 threshold), while treatments can reshape microbial communities, favoring stress-tolerant meristematic fungi. Regulatory pressure on fluorinated compounds drives the development of more sustainable alternatives. Emerging directions include stimuli-responsive systems, self-healing materials, slippery interfaces, and precision polymer architectures. However, future progress will depend on tailoring formulations to major lithotypes, improving compatibility with porous substrates, and validating performance through standardized accelerated aging and multi-year field trials. Bridging laboratory design with environmental exposure data and conservation practice will be essential for achieving durable and culturally acceptable protection strategies. Full article

The increasing global demand for oil and gas, together with the depletion of shallow reservoirs, has driven exploration toward deep and ultra-deep formations characterized by high-temperature and high-pressure (HTHP) conditions. In such environments, conventional drill pipes often experience thermal stress, corrosion, and mechanical degradation, which can reduce drilling efficiency and compromise operational reliability. Thermal insulated drilling pipes (TIDPs) have therefore emerged as an effective solution to minimize heat transfer between drilling fluids and the surrounding formation. This review summarizes recent advances in TIDP materials, structural design strategies, fabrication technologies, and critical performance. Relevant studies were collected from major scientific databases, including Web of Science and Google Scholar, with a focus on insulation materials, coating technologies, and thermal management approaches used in drilling systems. The analysis indicates that advanced insulation systems, including polymer-based coatings, silica aerogels, vacuum-insulated layers, and phase-change materials, can significantly enhance thermal management in drilling operations. These technologies can reduce heat loss by approximately 40–60% (i.e., 400–600 W·m⁻²) and maintain drilling-fluid temperature differentials of 10–18 °C under HTHP conditions. In addition, fabrication techniques such as plasma spraying, composite fabrication, and additive manufacturing enable the development of multifunctional insulation systems with improved thermal, mechanical, and corrosion-resistant properties. Hybrid TIDP systems integrating nanocomposites and advanced polymers show strong potential for improving drilling safety and efficiency. However, challenges related to durability, scalability, and cost remain, highlighting the need for further research on multilayer insulation architectures and sustainable materials. Full article

Polyaniline-cadmium sulfide-gold (PANI-CdS-Au) nanocomposites were synthesized with varying Au loadings (0.023, 0.046, 0.092 wt%) to enhance antibacterial performance. Structural (FTIR, XRD) and morphological (FESEM) analyses confirmed successful formation, with nearly homogeneous nanoparticle distribution (27–53 nm) and slight XRD peak shifts indicating interfacial interactions between PANI, CdS, and Au. UV–Vis spectra revealed gold surface plasmon resonance and polaronic transitions consistent with PANI emeraldine base. XRD results showed the expected wurtzite CdS and fcc Au phases. Agar well diffusion tests against Escherichia coli (Gram-negative) and Staphylococcus aureus (Gram-positive) demonstrated that the 0.092 wt% of Au composite produced the largest inhibition zones at 100 µg mL⁻¹ (E. coli: 36 mm; S. aureus: 24 mm), with the same trend at 25 µg mL⁻¹. The results indicate that PANI–CdS/Au nanocomposites are promising antibacterial materials; however, the presence of CdS necessitates additional cytotoxicity assays to confirm their suitability for medical applications. Full article

The incorporation of phase change materials in concrete is a practical strategy that holds great promise for enhancing the energy efficiency of buildings and reducing CO₂ emissions. However, the direct contact between phase change materials and cement interferes with the cement hydration reaction, leading to a significant reduction in the mechanical strength of cementitious composites. To encapsulate polyethylene glycol and prevent leakage, this study developed a shape-stabilized phase change aggregate via the cold-bonding method and the vacuum impregnation method. The nanoscale pore structure of the aggregate was regulated by adjusting the biochar content to enhance the phase-change material loading capacity. The phase change aggregate was characterized by indicators including crushing strength and water absorption. Meanwhile, its microstructure, the correlations between nano-sized hydration products, chemical compatibility, and phase change properties were analyzed. The fabricated phase change aggregate has a crushing strength of over 5 MPa, latent heat of 42.84 J/g, and phase change temperature of 29.17 °C while also exhibiting good mechanical properties and thermal energy storage performance. The compressive strength of phase change concrete can meet the strength requirements for structural building material. Moreover, phase change aggregate contributed to reduced CO₂ emissions during service, with favorable economic and low-carbon benefits over its service life, demonstrating good performance in both economic efficiency and CO₂ emission reduction. Full article

A novel graphene-based nanomaterial, trade registered Hastalex^®, has been synthesised and investigated for its application as a 3D scaffold in surgical implantation. Hastalex is developed through the covalent bonding of amine-group-functionalised graphene oxide to the base chemical, poly(carbonate-urea)urethane. The material is under development for medical application including tendon, heart valve, and pelvic implant for prolapse surgery. For successful clinical translation, long-term rheological and chemical stability must be demonstrated and until now no systematic multi-year evaluation has been reported for graphene-poly(carbonate-urea)urethane nanocomposites. The material was synthesised in accordance with the patented formulation and evaluated at 0, 6, 12, and 24 months post-synthesis. Physicochemical properties were assessed using attenuated total reflectance Fourier-transform infrared spectroscopy, scanning electron microscope, contact angle measurements, thermogravimetric analysis, and mechanical analysis with tensile tests. Flow behaviour of Hastalex was evaluated using a rheometer to determine viscosity, shear stress response and impact of temperature changes and ageing on these factors. Hastalex exhibited non-Newtonian, shear-thinning behaviour consistent across all timepoints. Viscosity was found to increase progressively with ageing, attributed not to chemical degradation, but likely due to gradual solvent evaporation and densification of the polymer matrix during storage under ambient conditions. Rheological measurements across increasing temperature regimes revealed a heat-sensitive decrease in viscosity, followed by a reversal of changes beyond ~80 °C—likely due to enhanced solvent evaporation and chain reorganisation. This comprehensive material characterisation supports Hastalex as a promising candidate for bioengineering applications. Full article

Background: Screw loosening remains a common mechanical complication in implant-supported restorations; however, the combined effect of sealing and superstructure materials on abutment screw stability warrants further investigation. Methods: This study evaluated the influence of access channel sealing material and superstructure material on abutment–implant screw stability after thermomechanical cyclic loading. Forty-eight Straumann analog–abutment assemblies restored with monolithic zirconia or resin nano-ceramic (Cerasmart) crowns were assigned to two sealing protocols: Polytetrafluoroethylene (PTFE) + composite or polyvinyl siloxane (PVS) putty (n = 12). After 750,000 off-axis cycles, reverse torque values (RTV) were analyzed using two-way analysis of variance (ANOVA) and Tukey’s HSD, with effect sizes calculated (α = 0.05). Results: A significant interaction between restorative material and sealing protocol was observed (p = 0.0170; η² = 0.116). Superstructure material showed no significant influence on RTV (p = 0.8368), whereas sealing protocol had a significant main effect (p = 0.0499). RTVs were highest for zirconia + PVS putty (36.33 ± 4.53 Ncm) and lowest for zirconia + PTFE (29.32 ± 6.30 Ncm), while the Cerasmart groups showed intermediate values. Post hoc analysis confirmed higher RTV for zirconia + PVS compared with zirconia + PTFE (p = 0.0138). Conclusions: Access channel sealing materials showed a material-dependent influence on abutment screw stability. Silicone-based sealing improved torque maintenance in zirconia, indicating that rigid restorative materials may be more sensitive to sealing material selection. In contrast, Cerasmart showed comparable RTV regardless of sealing protocol, suggesting that resilient restorative materials may reduce the influence of sealing on preload maintenance. Full article

Surface discharge-induced degradation poses a significant threat to the operational reliability of high-voltage insulation systems. This research investigates the dielectric endurance of polyester-based nanocomposites reinforced with seven distinct nano-additives: iron oxide (Fe₃O₄), copper oxide (CuO), titanium oxide (TiO₂), aluminum oxide (Al₂O₃), silicon dioxide (SiO₂), zinc borate (ZnB) and graphene oxide (GO). Specimens were fabricated at 0.5% and 0.75% weight concentrations and subjected to constant AC electrical stress of 4.5 kV at 50 Hz until failure using the first-plane tracking method. To accurately monitor the aging process, a sophisticated signal processing framework involving Hankel-matrix-enhanced Robust Principal Component Analysis (RPCA) was developed to extract high-frequency discharge features from captured leakage current signals. The degradation characteristics were quantified using various statistical metrics, including Kurtosis, RMS and Burst Discharge Index (BDI). Experimental findings demonstrate that the incorporation of nanoparticles significantly extends the time-to-failure compared to neat polyester, although the effectiveness is highly dependent on both additive type and concentration. At 0.5 wt.%, ZnB exhibited the superior performance in delaying carbonized track formation. However, at 0.75 wt.%, Al₂O₃ emerged as the most effective additive, achieving a maximum endurance time of 31.61 min. In contrast, certain additives like TiO₂ showed a performance decline at higher loadings, likely due to nanoparticle agglomeration. The Hankel-RPCA methodology successfully isolated discharge-specific signatures from background noise, establishing a strong correlation between signal features and material failure stages. This study confirms that the synergy between advanced nanomaterial modification and robust signal processing provides an effective diagnostic tool for monitoring insulation health, offering a vital pathway for the designing of high-performance dielectrics for real-world power system applications. Full article

Thermal management is critical for maintaining the safety and performance of lithium-ion batteries. Phase change materials (PCMs) have been widely studied as passive cooling media due to their high latent heat capacity, but major technical challenges remain due to their relatively low thermal conductivity and nanoparticle sedimentation in composite systems. In this work, a composite phase change material (PCM) consisting of paraffin wax, a microencapsulated phase change material (MicroPCM 28D), and nano carbon black is developed to enhance thermal stability and suppress particle sedimentation through increased viscosity of the PCM matrix. Five capsule geometries fabricated by fused filament fabrication (FFF) 3D printing are experimentally investigated under airflow velocities ranging from 0 to 10 m s⁻¹. Wind tunnel experiments with infrared thermography are used to evaluate the thermal response of the PCM capsules. The results show that airflow velocity and capsule geometry strongly influence heat dissipation behavior. Compared with conventional wax composites, the MicroPCM 28D composite capsules reduce peak temperature by approximately 2–4 °C under airflow velocities of 0–10 m/s. These findings provide insights into geometry-regulated convection and stable composite PCM design for lithium-ion battery thermal management systems. Full article

Carbon fiber reinforced polymer (CFRP) composites are widely used in many engineering applications such as aerospace, automotive, and defense industries due to their superior properties such as high specific strength, stiffness, and corrosion resistance. However, these materials require drilling, especially during assembly processes. Damage mechanisms arising during this process, such as delamination, high thrust force, and torque, negatively affect structural integrity and production quality. This study proposes a data-driven, multi-objective optimization approach to solve problems encountered during drilling in multi-walled carbon nanotube (MWCNT)-reinforced CFRP nanocomposites. The study considers the MWCNT reinforcement ratio, cutting speed, and feed rate as process parameters and examines their effects on thrust force, torque, and delamination factor. Second-degree polynomial regression-based prediction models were created using the experimental data obtained, and these models were included in the multi-objective optimization process. During the optimization phase, thrust force and torque values were simultaneously minimized, while the delamination factor was kept below the statistically determined constraint of F_d ≤ 1.054. Pareto-optimal solution sets were obtained using NSGA-II and MOPSO meta-heuristic algorithms in the solution process. The results indicate that suitable combinations of drilling parameters can be identified through Pareto-based optimization, allowing significant reductions in thrust force and torque while maintaining the delamination factor below the specified limit. The study presents a reliable optimization approach for the more efficient machining of CFRP nanocomposites. Full article

Supramolecular oleogel lubricants construct a three-dimensional network structure within base oils through gelator-mediated non-covalent interactions, such as hydrogen bonding, van der Waals forces, and π–π stacking. These materials demonstrate unique advantages in mitigating issues inherent to traditional lubricants, including leakage, volatility, creep, and poor heat dissipation. Focusing on structural design and performance regulation, this review systematically summarizes the current development of supramolecular oleogel lubricants in the fields of green lubrication, extreme operating conditions, and nanocomposite lubrication. Specifically, it outlines the structure-property relationships between gelators and base oils in green lubrication systems, and elucidates the applications in radiation-resistant, high-load-bearing, and intelligently responsive lubrication. Strategies for utilizing nanocomposite supramolecular oleogels to resolve nanomaterial dispersion challenges are discussed, and the latest advancements in engineering applications are illustrated. By summarizing the development of supramolecular oleogel materials, this work can provide theoretical references for the future design and preparation of these lubricants. Full article

Background: The aim of this in vitro study is to comparatively evaluate the effects of toothpaste formulations containing and not containing vitamin C on the surface roughness and microhardness of different composite resin materials. Methods: Four different toothpastes (Sensodyne, Colgate, Klorhex, Dentiste) and three composite resin materials (Arabesk—microhybrid, Charisma Smart—nanohybrid, Estelite Sigma Quick—supra-nano filled) were used in the study. Composite discs measuring 10 mm in diameter and 2 mm in thickness were prepared and subjected to brushing simulations equivalent to 1 month (150 s) and 3 months (450 s). Surface roughness was measured using a mechanical profilometer, and microhardness was evaluated with a Vickers hardness tester. Surface morphology was further examined in detail using scanning electron microscopy (SEM) and atomic force microscopy (AFM). For statistical analyses, one-way ANOVA, repeated measures ANOVA, Kruskal–Wallis test, and Friedman test were employed, with the significance level set at p < 0.05. Results: Brushing procedures resulted in statistically significant changes in the surface roughness (ΔRa) and microhardness of the composites across all toothpaste groups (p < 0.05). The increase in surface roughness varied depending on the composite type, with the highest increase observed in the ESQ composite. In the ESQ composite, higher ΔRa values were obtained, particularly in the Dentiste (≈1.70 µm) and Colgate (≈1.52 µm) groups. Microhardness results, however, differed depending on the composite and toothpaste type. While a general trend toward increased microhardness was observed, a significant decrease in microhardness was detected in the Colgate and Dentiste groups of the ESQ composite (p < 0.05). Conclusions: This study demonstrates that the addition of vitamin C to toothpaste formulations increases the surface roughness of restorative materials and results in significant changes in their microhardness properties. These findings highlight the importance of considering the type of toothpaste used by patients in clinical practice, particularly in terms of restorative material selection and the long-term preservation of surface integrity. Full article

Natural pumice can reduce the self-weight of concrete, but its high porosity, high water absorption, and weak interfacial bonding tend to limit the strength and durability of lightweight aggregate concrete. To address this issue, this study proposes a method for preparing and applying reinforced pumice lightweight aggregates, namely, using nano-SiO₂-modified fly ash to construct a nanocomposite material at the micro-interface for the reinforcement treatment of natural pumice aggregates, and reveals the mechanism by which this treatment enhances the performance of lightweight aggregate concrete. Through aggregate performance tests, compressive strength tests, XRD, SEM, and freeze–thaw cycle tests, the effects of the reinforced pumice aggregate on the performance of lightweight concrete were systematically investigated. The results show that after the reinforcement treatment, the water absorption of the pumice aggregate decreases by 17.6%, and the cylinder compressive strength increases by 34.3%. As the replacement ratio of reinforced pumice increases, both the early-age and later-age compressive strengths of the concrete continuously improve. When all the pumice aggregate is reinforced, the 3 d and 28 d compressive strengths increase by 35.1% and 33.44%, respectively. Meanwhile, the reinforced pumice effectively improves the interfacial bonding between the aggregate and the cement paste, reducing the width of the interfacial transition zone by 32%, enhancing the matrix compactness, and delaying crack propagation. The study demonstrates that the reinforced pumice aggregate possesses favorable characteristics, not only effectively improving the mechanical properties and freeze–thaw resistance of lightweight concrete but also providing a new technical pathway for the high-performance utilization of porous lightweight aggregates, offering a reference for the resource utilization of industrial solid waste and engineering applications in cold regions. Full article

Due to its strong near-infrared (NIR) absorption and high thermal conductivity, graphene is considered an excellent nanophotothermal filler that can effectively improve the photothermal conversion performance of composites. In particular, graphene–polymer nanocomposites, new types of photothermal conversion materials, have broad application prospects in photothermal therapy, photothermal driving, and micro-/nanomachinery. Recent research results have shown that when the filling concentration of graphene nanosheets (GNSs) in the matrix reaches the percolation threshold, interface effects such as interface tunneling and Maxwell–Wagner–Sillars (MWS) polarization, the key factors affecting the photothermal conversion performance of such composites, will occur. Furthermore, graphene exhibits unique optical conductivity due to its strong interaction with light. To reveal how interface effects influence the photothermal conversion performance of these nanocomposites, the optical conductivity of graphene at near-infrared frequencies was introduced to modify the effective medium theory. By combining this with a photothermal conversion model, the photothermal conversion behaviors of GNS–polymer composites are discussed, taking into account the interface effects and optical conductivity characteristics of GNSs. Full article

Agri-food waste valorization is critical for advancing sustainable packaging solutions. Citrus processing generates large amounts of peel residues that are often discarded, despite being rich in valuable biopolymers. This study presents a fully integrated, zero by-product valorization strategy for the fabrication and characterization of pectocellulosic nanocomposite films derived from orange peel (OP) biomass. Orange peel extract (OPE) was prepared and used for the biosynthesis of ZnO nanoparticles (NPs), while cellulose was obtained after the depectinization reinforced the pectin-rich supernatant used as the film-forming matrix (0–15% w/w). The optimized formulation containing 5% cellulose enhanced tensile strength by approximately 103% and reduced water vapor permeability by about 12.5% compared to the control, while maintaining structural homogeneity. Higher cellulose loading (≥10%) induced pore formation and compromised barrier and biological performance. Incorporation of ZnO NPs (1–5% w/w) into the optimized matrix further improved stiffness (YM = 163.9 MPa), improved UV-shielding capacity, antimicrobial activity (inhibition zones up to 16.0 mm), and antioxidant performance (98.2% ABTS inhibition). Biodegradation remained statistically unaffected by ZnO incorporation, with films retaining 29–35% degradation within 33 days. Overall, this work demonstrates the transformation of OP waste into multifunctional biodegradable active packaging materials, reinforcing circular bioeconomy principles. Full article

Contamination of water resources by organic pollutants is a major environmental issue. Utilizing photocatalytic materials for the degradation of these pollutants presents a viable strategy for environmental clean-up. This study introduces the synthesis of an organic/inorganic hybrid photocatalyst of β-cyclodextrin (β-CD)/reduced graphene oxide (rGO) and titanium oxide (TiO₂) nanoparticles. The nanocomposite was characterized by using FT-IR, XRD, SEM, and EDAX, and the photocatalytic activity was studied by measuring the photodegradation of methylene blue (MB) under simulated solar radiation. The synthesized nanocomposite showed excellent stability and performance, with up to 92% photodegradation of MB. To further enhance the photocatalytic activity, the synthesized nanocomposite underwent modification with Ag and Pt nanoparticles. Within 90 min, photodegradation rates of 100% and 97% for MB were attained with Pt and Ag nanoparticles that were loaded at 5 wt.%, respectively. The photocatalyst’s reusability was evaluated through multiple usage cycles. Additionally, the impact of functionalization on the band gap alteration of TiO₂ is reported. Full article