Search Results (1,972)

Increasing traffic volumes, heavier axle loads, and the growing frequency of premature pavement distress pose major challenges for modern road infrastructure. In many regions, asphalt pavements experience early rutting, cracking, and moisture-induced damage, underscoring the need for improved material performance and longer service life. Reinforcing fibres are increasingly used to enhance asphalt mixture properties, with aramid fibres recognised for their superior mechanical and thermal stability. This study evaluates the effect of FlexForce (FF) fibres on the mechanical and fracture behaviour of two dense-graded asphalt concretes, AC 16 surf and AC 16 bin, produced with different binders and fibre dosages (0.02% and 0.04% by mixture weight). Laboratory tests, including indirect tensile strength ratio (ITSR), indirect tensile stiffness modulus (IT-CY), crack propagation resistance, and dynamic modulus measurements, were performed to assess moisture susceptibility, stiffness, and viscoelastic behaviour. The results showed that fibre addition had little effect on compactability and stiffness under standard conditions but improved temperature stability and stiffness at elevated temperatures, particularly when used with polymer-modified binders. Moisture resistance decreased slightly, while fracture performance improved moderately at intermediate temperatures. Overall, low fibre dosages (~0.02%) provided the most balanced performance, indicating that the mechanical benefits of aramid reinforcement depend strongly on binder rheology, temperature, and interfacial compatibility. These findings contribute to optimising fibre dosage and binder selection for aramid-reinforced asphalt layers in practice. Full article

The present paper focuses on the effect of carbon nanotubes (CNTs) on the rheological behavior of polyethylene/polypropylene (PE/PP) blends to improve PE/PP mixtures for industrial applications. In our research, 40 wt% HDPE-60 wt% PP blends were produced by extrusion, and 0.59%, 1.18%, and 2.35% multiwalled carbon nanotubes (MWCNTs) were added. Oscillation rheometry was used to study the HDPE-PP-MWCNT nanocomposites and the unfilled polymers at temperatures of 210, 220, 230, 240, and 250 °C in the angular frequency range of 0.05–628.32 rad/s, with 5% deformation. It was demonstrated that in the presence of CNTs, both the complex viscosity and modulus values increase above the percolation threshold. Additionally, it was observed that the crossover modulus (Gx) for all mixtures decreases with increasing temperature. In addition, at 1.18% CNT content, a second crossover appears at all temperatures, and its value increases with temperature. Full article

The aim of the work was to obtain poly(butylene succinate)—a PBS biocomposite material with an addition of natural sodium montmorillonite (Na-MMT) modified with two selected terpenes: pinene (P) and limonene (L) or their mixture (PL)—and examine their physico-chemical, rheological, and antiviral properties. Na-MMT was effectively hydrophobized and intercalated (confirmed with FTIR, TGA, and XRD analysis results) with the terpenes via the solventless method. The materials were obtained via extrusion, and the films were formed using thermo-compression molding. The addition of the fillers slightly increased mechanical properties, but barrier properties towards oxygen and water vapor were significantly improved (OTR from 52 to 28 cm³/m²∙24 h and WVTR 21 to 11 g/m²∙24 h for PBS and composite, respectively) without alteration of polymer morphology (SEM, XRD, FTIR) or thermal and thermomechanical properties, despite high filler content (10 wt%) in the polymer matrix. Surface contact angle values of PBS/M, PBS/M-L, and PBS/M-PL exhibited antiviral properties and were tested using Φ6 bacteriophage. The composites can be used for materials in medical and food packaging applications. Full article

Expanded polystyrene (EPS), a lightweight thermoplastic polymer widely used in packaging and insulation, has become a growing environmental concern due to its non-biodegradable nature and escalating global consumption. Although EPS waste shows potential in construction applications, previous studies have primarily incorporated it into mortars, concrete, or soil–cement mixtures, often relying on the addition of cement to improve its mechanical performance. This approach compromises sustainability and has generally overlooked the role of microstructural interactions in the behavior of soil–EPS waste mixes without cement. This study differs from prior works by exploring the mechanical and microstructural properties of soil–EPS waste mixtures without cementitious binders under different compaction energies. Experimental tests were carried out for the technical characterization of soils, ground EPS waste, and mixtures of soil and different contents of EPS waste (0%, 20%, 30%, and 40% of the total apparent volume of the composite), using different compaction energies (Intermediate and Modified Proctor). The mixtures were subjected to Unconfined Compressive Strength (UCS), California Bearing Ratio (CBR), and direct shear strength tests, in addition to physical and microstructural characterization. The results indicated that both soil type and compaction energy influenced the engineering behavior of the mixtures. The clayey soil exhibited superior mechanical performance, while the sandy soil showed reductions in all mechanical properties. The UCS values of the clayey soil with the addition of EPS did not change significantly (297 kPa to 286 kPa at intermediate energy and 514 kPa to 505 kPa at modified energy), while for the sandy soil, there was a decrease in values (from 167 kPa to 46 kPa at intermediate energy and from 291 kPa to 104 kPa at modified energy). In the CBR tests, only the 20% and 30% addition of EPS to the clayey soil, using the Modified Proctor energy, showed an increase (from 18% to 20% for both percentages). This behavior was primarily attributed to adhesion mechanisms at the soil–EPS waste interface, with friction playing a secondary role, thereby suggesting that clayey soils may offer better mechanical response. The lower dry density of these mixtures compared to compacted natural soils presents a technical benefit for use as backfill in areas with low bearing capacity, where minimizing the load from the fill material is critical. Full article

Exhaled breath analysis is emerging as one of the most promising non-invasive strategies for the early detection of life-threatening diseases, especially lung cancer, where rapid and reliable diagnosis remains a major clinical challenge. In this study, we designed and optimized an electronic nose (e-nose) platform composed of quantum resistive vapor sensors (vQRSs) engineered by polymer-carbon nanotube nanocomposites via spray layer-by-layer assembly. Each sensor was tailored through specific polymer functionalization to tune selectivity and enhance sensitivity toward volatile organic compounds (VOCs) of medical relevance. The sensor array, combined with linear discriminant analysis (LDA), demonstrated the ability to accurately discriminate between cancer-related biomarkers in synthetic blends, even when present at trace concentrations within complex volatile backgrounds. Beyond artificial mixtures, the system successfully distinguished real exhaled breath samples collected under challenging conditions, including before and after smoking and alcohol consumption. These results not only validate the robustness and reproducibility of the vQRS-based array but also highlight its potential as a versatile diagnostic tool. Overall, this work underscores the relevance of nanocomposite chemo-resistive arrays for breathomics and paves the way for their integration into future portable e-nose devices dedicated to telemedicine, continuous monitoring, and early-stage disease diagnosis. Full article

The basis of the construction industry is building materials with high-quality indicators in terms of physical, mechanical, and thermophysical characteristics, however, there are a number of issues affecting the quality of manufactured products. The development of the construction industry provides new opportunities for designing efficient construction facilities. To obtain enhanced design capabilities, it is very important to relieve the load on the structure, and this can be achieved by reducing the mass of materials without losing strength. This study investigates the enhancement of foam concrete through the combined incorporation of mineral fibers recycled from basalt insulation waste and complex polymer modifiers. The aim was to improve the material’s mechanical performance, durability, and pore structure stability while promoting sustainable use of industrial by-products. The experimental program included tests on density, compressive strength, water absorption, and thermal conductivity for mixtures of different densities (400–1100 kg/m³). Results demonstrated that the inclusion of mineral fibers and polymer modifiers significantly enhanced structural uniformity and pore wall integrity. Compressive strength increased by up to 35%, water absorption decreased by 25%, and thermal conductivity was reduced by 18% compared with the control mixture. Full article

The high-temperature thermal stability of dexamethasone (DEX) was systematically investigated under nitrogen and air atmospheres using non-isothermal thermogravimetry at heating rates of 0.1–20 °C·min⁻¹. The thermal decomposition was found to initiate below the melting temperature, proceeding via a three-step pathway that generated a complex mixture of volatile and condensed by-products (~10% solid residuum at 550 °C). Kinetic modeling was realized using the single-curve multivariate kinetic analysis (sc-MKA), and was based on the autocatalytic framework with temperature-dependent parameters, combined with consequent reaction mechanisms. An excellent agreement of the theoretical model with the experimental data enabled reliable predictive extrapolations to pharmaceutical processing conditions. Whereas the onset of degradation was observed at ~180–190 °C, significant decomposition rates (>1% mass loss during first 5 min) were only reached above 220 °C, well above the processing windows of most pharmaceutical polymers. Consequently, dexamethasone can be considered thermally stable for hot-melt extrusion and fused deposition modeling, except in high-temperature-processing applications involving polymers such as, e.g., polylactic acid, polyvinyl alcohol, or thermoplastic polyurethanes. Importantly, the study highlights that reliable kinetic predictions require measurements across a broad heating-rate range and in both oxidizing and inert atmospheres, with special emphasis on low heating rates (≤0.2 °C·min⁻¹), which proved critical for capturing early-stage degradation. These findings provide a rigorous kinetic framework for ensuring safe incorporation of DEX into advanced pharmaceutical and medical device formulations. Full article

The fields of healthcare and pharmaceutical science are increasingly focused on developing innovative and effective treatments. This trend is driven by a growing consumer demand for natural, sustainable, and highly functional polymer-based products. This study focuses on two biomaterials: chitosan and royal jelly. Chitosan, a linear polysaccharide derived from chitin, is well-regarded for its hemostatic and antimicrobial properties, making it an excellent candidate for wound healing applications. Royal jelly, a nutrient-rich secretion from honeybees, represents a complex mixture of proteins, lipids, vitamins, and antioxidants, notably 10-hydroxy-2-decenoic acid (10-H2DA). It is known for its anti-inflammatory, antioxidant, and regenerative effects on the skin. While the individual benefits of chitosan and royal jelly are well-documented, there is a significant research gap concerning their synergistic application in various treatments such as topical formulations, wound healing, regenerative medicine, and delivery transport processes. Ultimately, this review concludes that the synergistic effects of chitosan and royal jelly could provide a material platform with a superior dual-action profile, integrating the structural and antimicrobial benefits of chitosan with the powerful regenerative and anti-inflammatory effects of royal jelly. This synergy strongly supports their utility in developing next-generation, high-performance natural bioproducts for wound healing, bone regeneration, agriculture, or aquaculture applications. Full article

The growing demand for sustainable solutions in the plastics industry has highlighted the need to reintroduce post-industrial polymer waste into high-performance applications. This study focuses on the mechanical recycling of automotive scraps containing variable proportions of polycarbonate (PC), acrylonitrile–butadiene–styrene (ABS), and a commercial PC/ABS blend. After determining the composition of two representative batches, a screening of seven commercial compatibilizers and impact modifiers was performed to improve impact strength. Among them, an ethylene–methyl acrylate–glycidyl methacrylate (E-MA-GMA) terpolymer was identified as the most effective additive. Its influence was further investigated through a mixture design approach, varying the composition of the three polymer phases and the additive content (0–10 wt.%). The resulting response surface model revealed a significant increase in impact resistance in PC-rich formulations with increasing E-MA-GMA content, while ABS and PC/ABS showed more complex trends. Rheological, mechanical, and thermal analyses supported the observed behavior, suggesting improved matrix compatibility and reduced degradation during processing. The proposed model enables the prediction of impact performance across a wide range of compositions, offering a practical tool for the optimization of recycled blends. These findings support the potential of targeted compatibilization strategies for closed-loop recycling in the automotive sector. Full article

Despite its remarkable moisturizing properties, the inherently high viscosity of high-molecular-weight hyaluronic acid (HA) restricts its practical application in skincare products, cosmetic formulations, and skin-contact medical devices. To overcome this limitation, we propose the incorporation of branched structures into HA to create a branched HA hybrid (bHH) by chemically coupling low-molecular-weight HA (200 kDa) with high-molecular-weight HA (700–2500 kDa). The introduction of branched structures into the HA backbone alters the viscosity of high-molecular-weight HA while preserving its moisturizing potential. Branching reduces the solution viscosity of linear HA, particularly at higher polymer concentrations. In this study, the moisturizing efficacies of branched and linear HAs were extensively evaluated. Branched HA demonstrated equivalent or superior moisturizing effectiveness compared with linear HA and even significantly enhanced the water-binding capacity over simple mixtures of linear HAs. These findings suggest that introducing branched structures can effectively reduce the solution viscosity of linear HA without compromising its moisturizing properties, thereby improving the usability and hydration performance of skincare products and skin-contact devices. Full article

In this study, a surface texture design technique for 3D-extruded prototype products was developed. The study determines some target functional properties of polymer-made items. Four series of experimental samples (acrylonitrile–butadiene–styrene (ABS), thermoplastic polyurethane (TPU), polylactide (PLA), and polyethylene terephthalate glycol (PETG)) were 3D-printed using the fused filament fabrication (FFF) approach. The morphology and hydrophilic/hydrophobic balance of the surfaces of the experimental samples were regulated directly by the 3D design and by gas-phase fluorination techniques. The observed distilled water and ethylene glycol edge wetting angles of the surfaces of the experimental samples were determined by a 3D filament stroke arrangement. It was shown that varying the 3D design promoted hydrophobization and provided anisotropic wetting (the distilled water edge angle of the same sample varies from 76 to 116 degrees). The textured surfaces simultaneously demonstrated hydrophilicity in one direction and hydrophobicity in the other. The changing of the fluorine-containing gas mixture surface treatment duration allowed us to alter the hydrophilic/hydrophobic balance of 3D-extruded prototypes. The fluorination kinetics of the experimental samples were studied empirically. The combination of macroscopic surface design (through FFF 3D printing) and microscopic surface modification (through gas-phase fluorination) permitted a significant reduction in the straining friction coefficient and increased the wettability of the complex-shaped 3D-printed products. Full article

Waste prevention is at the top of the EU Waste Framework directive hierarchy. With this in mind, this article considers the application of novel technologies in the Cultural Heritage Restoration and Conservation field through environmental and circular economy principles. While previous research has explored the use of wood waste for composite materials such as building insulation and concrete additives, the suitability of degraded historical wood waste for filament production and 3D printing has not yet been addressed. This article contributes to this topic by studying the PLA/wood composite, material composed of a polylactic acid (PLA) polymer matrix reinforced with wood particles, produced from degraded historical construction materials. The paper describes the process of producing filament from bio- and moisture-damaged pine beam and oak parquet, followed by the 3D printing of historical platband replica. Research methods include photogrammetry, filament machine construction, filament production and 3D printing. The machines settings used in the process: heater temperatures were set to 140 °C, 90 °C and 105 °C; servo speed was 33 s; spool tension was 12.5; winding speed was 24 RPM; and screw speed was 9.2 RPM. For material preparation, a mixture containing 25% pine and oak sawdust and PLA dust was processed to achieve particle sizes of 312 μm, 471 μm, and 432 μm, respectively. Filament production was carried out with diameters of 2.85 mm for the pine/PLA composite and 1.75 mm for the oak/PLA composite. Finally, replica samples were fabricated using 3D printing. The dual objective of this research was to develop the method of 3D printing from degraded historical materials and introduce it to restoration practice as a wood waste minimization technique. Perspectives for further study include the testing of 3D-printed construction materials in outdoor conditions, and pellet production to achieve a higher wood content, compared to the filament thread. The processes described are adaptable to a variety of materials and disciplines. Full article

Cyanobacterial blooms have been increasingly detected in estuaries and freshwater tidal rivers. To enhance detailed monitoring, an efficient approach to detecting algal blooms through remote sensing is needed to focus more detailed monitoring focused on cyanobacteria. In this study, we compared different remote sensing processing methods to determine an efficient approach to mapping chlorophyll-a. Using a subset of paired chlorophyll-a observations with Sentinel-2 imagery (2015–2022), with sites located in the Chesapeake Bay and Indian River selected along gradients of salinity, turbidity, and trophic status, we compared the combined performance of two different atmospheric processing methods (Acolite, Polymer) and a suite of empirical (band ratio, spectral shape indices) and machine learning algorithms for chlorophyll-a prediction. Acolite outperformed Polymer, resulting in 176 observation points, compared to 106 observation points from Polymer, and a greater range in chlorophyll-a values (0–74 μg/L from Acolite compared to 0–36 μg/L from Polymer), although Polymer showed more responsiveness at lower chlorophyll-a levels. Two algorithms performed best in predicting chlorophyll-a, as well as trophic state and HABs risk classes: the machine learning mixture density network (MDN) approach and the one band-ratio approach (Mishra). Full article

The rational design of advanced composite gels requires rigorous rheological analysis to decode their flow-deformation mechanisms, a prerequisite for optimizing performance in food and biomedical applications. However, systematic thermal analysis and rheological profiling of Salecan/Sanxan hydrogels remain unexplored, constituting a critical knowledge gap in this field. This study engineered Salecan/Sanxan hydrogels and systematically probed Salecan-dependent rheological and thermal properties. Through Power Law and Herschel–Bulkley model analyses, the hydrogels demonstrated composition-dependent rheological properties: yield stress (4.7–29.2 Pa), η₅₀ (342.6–3011.4 mPa·s), and Arrhenius equation fitting revealed tunable activation energy (14,688.3–30,997.1 J·mol⁻¹). Notably, when the gel was formulated with 3% Sanxan and 2% Salecan at a volume ratio of 1:2, its thermal-decomposition temperature rose by 9%, from 224.4 °C to 245.1 °C. Conversely, a 1:1 mixture of 2% Sanxan and 2% Salecan produced the lowest freezing point recorded (–18.3 °C), an 18% reduction compared with the control (–15.4 °C). These findings demonstrate the tunable rheological and thermal properties of Salecan/Sanxan hydrogels. By establishing that precise modulation of polymer mixing ratios can match the entire processing shear spectrum, this study not only fills a critical knowledge gap but also creates a versatile platform for designing tailor-made foods and biomedical matrices. Full article

Biosurfactants are amphipathic compounds produced by various microorganisms, including fungi and yeasts, with those produced by the latter being of particular interest as they are considered microorganisms of low or no sanitary risk. This article presents an analysis of the available information regarding the role these compounds play within the ecological habitat where yeasts inhabit, as well as their potential biotechnological applications in commercial areas. Some of the biological roles that biosurfactants play for their producing microorganisms are unknown and can be highly diverse, depending on the adaptive needs microorganisms have to survive the environmental conditions prevalent in their habitat. However, some of these roles that have been reported are related to nutrient availability, cellular communication, and competition, as well as surface colonization. The structures of biosurfactant molecules produced by yeasts are highly diverse, and so far, have been reported as sophorolipids, carbohydrate–protein–lipid complexes, carbohydrate–protein polymers, mixtures of lactones, and mannosylerythritol lipids. In addition to their properties as surfactants and/or emulsifiers, many of these molecules have also been reported to possess biological activities, including antimicrobial, antifungal, antitumoral, antioxidant, antiadhesive, antiviral, ultraviolet (UV)-protectant, anti-aging agent, moisturizing, and enzyme-activator/inhibitor properties. By understanding the functions that biosurfactants perform in nature, novel and efficient methods for their production can be proposed, as well as new applications in areas such as pharmaceuticals, food, and cosmetics. The latter is of particular interest due to the growing biosurfactant market and the processes that demand greater knowledge about their production, biological, and environmental interactions for their management and disposal. Full article