Search Results (7,314)

The growing demand for low-carbon cementitious materials has increased interest in natural zeolite as a supplementary cementitious material capable of reducing clinker consumption while modifying cement system performance. This study presents an integrated experimental evaluation of natural zeolite-modified cementitious materials by combining rheological behavior, hydration, compressive strength, density, scanning electron microscopy (SEM), and X-ray diffraction (XRD) within a single experimental framework. Natural zeolite was used as a partial replacement for cement at dosages of 5–12.5 wt.%. The results showed that zeolite significantly affected both fresh-state and hardened-state properties. Zeolite increased the rheological resistance of fresh mixtures, shifted the exothermic hydration peak from 12 h to 8–10 h, and reduced the maximum hydration temperature by approximately 8–12%. Among the investigated compositions, the mixture containing 7.5% zeolite exhibited the highest compressive strength (44.9 MPa at 28 days) together with increased hardened density, suggesting more efficient particle packing and matrix development than the reference mixture. SEM observations indicated a more uniform distribution of hydration products in mixtures containing moderate zeolite dosages, while XRD analysis confirmed changes in the crystalline phase assemblage associated with zeolite incorporation. The results demonstrate that moderate natural zeolite replacement, particularly at 7.5%, provides an effective balance between rheological behavior, hydration characteristics, mechanical performance, and microstructural development, highlighting its potential as a sustainable supplementary cementitious material for low-carbon cement-based composites. Full article

The growing demand for effective delivery of active ingredients in cosmetic formulations has stimulated the development of advanced carrier systems. This study evaluates the potential of the dicephalic di-N-oxide surfactant N,N-bis [3,3-(dimethylamino)-propyl]dodecylamide (C₁₂-(DAPANO)₂) as a stabilizer for aqueous dispersions of solid lipid nanoparticles (SLNs) and nanostructured lipid carriers (NLCs). Lipid nanoparticles were prepared using three classes of solid lipids—cetyl palmitate, glyceryl behenate, and stearic acid—through high-speed homogenization followed by ultrasonication. Their physicochemical properties were characterized using DLS, TEM, AFM, DSC, and TGA. All formulations exhibited particle sizes below 300 nm and a low polydispersity index (<0.30), indicating good uniformity. High absolute zeta potential values and stability studies confirmed excellent physical stability, with all dispersions remaining stable for at least 90 days at room temperature. Compared with bulk lipids, nanoparticles showed lower melting temperatures and reduced crystallinity. NLCs exhibited lower crystallization and melting temperatures than SLNs and displayed a more spherical morphology. Cytotoxicity assessment using J774.E macrophages revealed no adverse effects. These findings highlight the surfactant’s potential as a stabilizing agent for lipid-based cosmetic nanocarriers, supporting the development of stable systems with improved active ingredient loading and controlled release properties. Full article

Changes in wood moisture content significantly affect its dimensions, mechanical properties, and vibrational characteristics. Thermal treatment is one of the most convenient approaches for improving the moisture resistance of wood; however, the effects of treatment conditions on moisture content and vibrational characteristics after short-term cyclic moisture absorption have not been clearly investigated. In this study, dry thermal treatment at 160–220 °C for three different durations was applied to Japanese cedar specimens. Higher thermal treatment temperatures and longer treatment times decreased the equilibrium moisture content (EMC). The fundamental resonant frequency of the free–free flexural vibration (f₁) increased with increasing treatment temperature, whereas it decreased over a longer duration. All specimens were subjected to three cycles of moisture change tests from 60%RH to 98%RH at 40 °C to track the change in moisture content, f₁ and its loss tangent (tanδ). The specimens treated at higher temperatures maintained a lower moisture content and higher f₁. Under most treatment conditions, the moisture content at 98%RH increased from the first to the second cycle and remained constant in the third cycle. On the other hand, the resonant frequency at 98%RH remained unchanged from the first to the second cycle but increased in the third cycle. This indicates that the moisture surface became saturated in the second cycle, and moisture diffusion from the surface to the inside of the specimen increased with the number of cycles. Near-infrared absorption revealed that high-temperature treatment caused thermal decomposition of hemicellulose and an increase in apparent crystallinity due to a reduction in the amorphous region of cellulose. These changes enhance the hydrophobicity of the cell wall, contributing to moisture resistance and vibrational stability. Full article

Sodium alginate was extracted from beach-cast Sargassum spp. collected along the coast of Puerto Progreso, Yucatán, Mexico, using two established pretreatment routes based on formaldehyde and ethanol. This study evaluates how extraction methodology controls alginate recovery, molecular structure, hydrogel rheology, macroscopic integrity, swelling behavior, and preliminary inorganic contaminant profiles. The ethanol-based route provided the highest extraction yield, reaching 19.87 ± 0.79% w/w for AE-5, whereas the formaldehyde route reached a maximum of 15.60 ± 0.62% w/w for AF-12; statistical analysis confirmed significant differences among extraction conditions (ANOVA, p < 0.05). Despite its lower yield, the formaldehyde route produced alginate with higher intrinsic viscosity (2.13 dL/g) and viscosity-average molecular weight (1.00 × 105 g/mol) than the ethanol-derived sample (1.33 dL/g and 0.62 × 105 g/mol), indicating better preservation of polymer chain length. ¹H NMR analysis showed that AE-5 had higher guluronic acid content (F_G = 0.60), lower M/G ratio (0.67), and higher G-block fraction (F_GG = 0.54), favoring Ca²⁺-mediated junction zone formation. Consequently, AE-5-derived hydrogels exhibited the highest storage modulus at 1 Hz (G′ = 23,650 Pa), compared with AF-12-derived hydrogels (13,160 Pa) and the commercial reference (14,480 Pa). However, visual inspection and swelling analysis showed that the higher small-amplitude stiffness of AE-5 did not translate into superior macroscopic integrity; these hydrogels showed greater fragmentation during handling and higher long-term swelling. In contrast, AF-12-derived hydrogels showed lower stiffness but better apparent cohesion and a more restricted swelling profile, consistent with enhanced long-range network connectivity derived from higher molecular weight. FTIR confirmed preservation of the characteristic functional groups of sodium alginate, whereas XRD provided qualitative evidence of residual crystalline inorganic phases. Selected-metal analysis by MP-AES detected Cu in both extracted alginates, while As was detected but not quantified only in AF-12; Cd and Pb were not detected under the analytical conditions employed. Overall, the results establish a route-dependent structure-property relationship in which extraction conditions govern yield, chain preservation, block architecture, viscoelastic response, swelling behavior, and preliminary contaminant profile. These findings support beach-cast Sargassum as a promising source of research-grade sodium alginate, while emphasizing that further purification, expanded contaminant profiling, arsenic speciation, biological evaluation, and direct mechanical testing are required before any food, biomedical, pharmaceutical, or environmental application can be proposed. Full article

Quaternary β-Ti-xTa-xZr-xNb (TTZN) alloys (x = 10, 20, and 30 wt%) were surface-modified by plasma electrolytic oxidation (PEO) to improve their surface properties. This treatment promotes the incorporation of bioactive ions, such as Ca and P, and favors the formation of a porous anodic surface resulting from the oxidation of the precursor metals. This study investigated how the addition of alloying elements (Zr, Ta, and Nb) influences oxide formation, PEO-induced pore morphology, wettability, and coating hardness. The surfaces were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS), Vickers microhardness testing, and wettability analysis. XRD analysis revealed that the TTZN10 alloy exhibited crystalline TiO₂ phases in the form of anatase and rutile. In contrast, the TTZN20 and TTZN30 alloys exhibited only cubic ZrO₂ diffraction peaks, while no TiO₂ peaks were detected within the detection limits of the XRD technique. Micrographs showed micrometric pores on all alloy surfaces. The TTZN20 alloy exhibited the highest porosity (31.8%), which correlated with lower hydrophilicity (θ = 79°) and high surface free energy (67 mJ/m²). After PEO treatment, all surfaces exhibited high hardness values ranging from 491 to 561 HV. The highest hardness was observed for TTZN10, attributed to the mixed anatase/rutile TiO₂ phase composition. Full article

This study (Part B) examines the potential utilization of municipal solid waste (MSW) ash, produced in a semi-industrial incinerator in Israel, as a partial substitute for cement and natural sand in industrial concrete mixtures. The ash was produced at the temperature range 600–850 °C, and the ash was characterized using XRD and SEM to determine its mineralogical composition and morphology. The results indicate that ash composition is dominated by calcium-rich phases, with hatrurite (Ca₃SiO₅) representing approximately 51–66 wt.% of the identified crystalline phases, along with calcite, MgO, and silica phases. The ash consists of irregular, porous particles with a broad distribution. Concrete performance was evaluated in both fresh and hardened states. In terms of fresh concrete properties, it is observed that concrete containing ash showed improved workability, better workability retention, and better concrete density compared to concrete without ash. In terms of hardened concrete properties, the use of MSW ash as a partial sand replacement preserved the mechanical performance of the concrete, with compressive strength remaining within approximately 2% of the reference mixture. These findings suggest that semi-industrially produced MSW ash is more suitable as a fine aggregate replacement than as a supplementary cementitious material and represents a promising route for reducing landfill disposal and promoting circular economy practices in the construction industry. Full article

To improve the foamability and steam-chest molding performance of polypropylene (PP) bead foams, ethylene-propylene rubber (EPR) was introduced into PP via melt blending. The role of EPR in the complete bead-foaming-to-molding process was systematically investigated by correlating phase morphology, crystallization behavior, melt viscoelasticity, CO₂ dissolution and diffusion, cellular structure, inter-bead welding, and the mechanical properties of molded foam products. The incorporation of EPR refined the PP crystalline morphology, reduced the apparent crystallinity, and markedly enhanced the melt viscoelasticity, thereby broadening the foaming temperature window. The dispersed EPR phase functioned simultaneously as a CO₂ reservoir and a high-diffusivity pathway of CO₂, which promoted cell growth while suppressing excessive nucleation. The enhanced melt viscoelasticity and improved CO₂ affinity promoted bead expansion and optimized the cellular structure. At 150 °C, the expansion ratio increased from 18.7 for neat PP to 21.1 with 10 wt% EPR. EPR also regulated the cellular structure. At 150 °C, the cell diameter increased from 83 to 176 μm as the EPR content increased from 0 to 20 wt%. EPR markedly changed the double-melting behavior of PP bead foams. The low-temperature melting enthalpy increased from 28.5 J/g for neat PP to 37.8 J/g with 10 wt% EPR, which served as an effective interfacial binder, significantly promoting inter-bead welding. Consequently, the optimized PP/EPR foam containing 10 wt% EPR exhibited a tensile strength of 1.13 MPa and an elongation at break of 22.1%. More importantly, excellent molding quality was achieved at a reduced steam pressure of 2.2 bar, demonstrating the great potential of PP/EPR bead foams for the energy-efficient manufacturing of high-performance lightweight products. Full article

The increasing concentration of atmospheric CO₂ has intensified the urgent need for efficient and sustainable carbon capture technologies. Covalent organic frameworks (COFs) have emerged as a highly promising class of porous crystalline materials for CO₂ adsorption and separation owing to their structural tunability, high surface area, and precisely designable pore environments. This review summarizes recent advances in COF-based CO₂ capture systems, covering pristine COFs, functionalized frameworks, composite materials, and membrane-based architectures. In pristine COFs, CO₂ adsorption is mainly governed by micropore confinement and physisorption within well-defined channels, where surface area and pore size distribution play key roles. Functionalized COFs introduce additional active sites, including amine groups, heteroatoms, ionic functionalities, and alkali metal centers, which significantly enhance CO₂ affinity through stronger electrostatic and acid–base interactions, often leading to mixed physisorption–chemisorption behavior. Composite COFs and mixed-matrix membranes further improve performance through synergistic effects, interfacial engineering, and enhanced mass transport. Despite these advantages, challenges remain in achieving an optimal balance between capacity, selectivity, and regenerability under realistic conditions such as humidity, low CO₂ partial pressure, and multicomponent gas streams. Issues related to scalable synthesis, structural stability, and processability also limit practical applications. Overall, this review highlights key structure–property relationships and outlines future directions, including humid-stable COFs, direct air capture, computational design strategies, and advanced membrane technologies, for next-generation CO₂ capture materials. Full article

Dietary fibers are valuable food components with documented health benefits, yet their native compact and highly crystalline structures often result in low water hydration, poor adsorption capacity, and limited bioactivity. Chemical modification offers a promising strategy to overcome these functional limitations by disrupting the dense structure and exposing active groups. This study aimed to investigate the effects of acid modification on the physicochemical properties of soybean and citrus dietary fibers and to evaluate the performance of the modified fibers in probiotic-fermented soy protein gels. Compared with native fibers, modified fibers exhibited reduced particle size, rougher and more porous microstructures, and increased exposure of hydroxyl groups. Consequently, they showed significantly (p < 0.05) enhanced hydration capacity (increased by 92–541%), antioxidant activity (increased by 15–65%), cholesterol adsorption (increased by 16–75%), and α-amylase inhibition (increased by 26–62%). When incorporated into soy protein-based gels, the modified fibers, particularly those from soybean, lowered gel pH, increased water holding capacity, gel strength, apparent viscosity, and storage modulus, while reducing strain, indicating improved gel network integrity. These findings indicate that acid modification effectively unlocks the functional potential of dietary fibers, positioning the modified fibers, especially from soybean, as promising prebiotic ingredients for plant-based fermented gel products. Full article

Glycolysis of poly(ethylene terephthalate) (PET) offers a promising route for chemical recycling, yet conventional homogeneous catalysts often suffer from low selectivity, severe side reactions (especially diethylene glycol, DEG formation), and detrimental metal residues that compromise the quality of recycled products. To address these challenges, we herein develop dipotassium phenylphosphonate (PPOA-K) as an efficient homogeneous catalyst for PET glycolysis. Under optimized conditions (1 wt% catalyst, 197 °C, EG/PET mass ratio 3:1, 90 min, atmospheric pressure), PPOA-K achieves 100% PET depolymerization and a high BHET yield of 86.0%, and the reaction follows apparent first-order kinetics with an activation energy of 70.3 kJ·mol⁻¹. Beyond its high catalytic activity, PPOA-K effectively suppresses the acid-catalyzed etherification of ethylene glycol to DEG, a common side reaction that reduces monomer purity and degrades recycled polyester properties. Remarkably, the trace amount of PPOA-K remaining in the recovered BHET (17.3 ppm) is not detrimental; instead, it continues to inhibit DEG formation during repolymerization and acts as a thermal stabilizer, improving the melting point and thermal stability of recycled PET. The advantages of PPOA-K are further demonstrated in a partial (in situ) glycolysis–repolymerization process, where it reduces the DEG content in the final rPET to 1.78% (vs. 2.25% for conventional Zn(OAc)₂), yielding rPET with a higher melting point, higher crystallinity, and better color. This work demonstrates that dipotassium phenylphosphonate uniquely combines high catalytic activity, side reaction suppression, and beneficial residue effects, offering a new catalyst design strategy for high-quality PET recycling. Full article

Waterlogged archaeological wood represents a unique cultural heritage but is highly susceptible to physical and chemical degradation, which complicates conservation and restoration. This study aimed to prepare artificial archaeological Cunninghamia lanceolata wood using NaOH vacuum impregnation and systematically evaluate the effects of NaOH concentration and treatment cycles as two treatment variables on wood degradation. Untreated heartwood specimens were treated with 5%, 10%, 20%, and 30% NaOH solutions for 2, 4, and 6 cycles. The NaOH treatment first induced chemical and structural deterioration, including selective degradation of hemicelluloses, changes in cellulose crystallinity, and progressive damage to the wood cell-wall structure. XRD analysis revealed a significant reduction in cellulose crystallinity from 35.96% to 10.11%, while FTIR confirmed the degradation of hemicelluloses and the relative enrichment of lignin-related structures. SEM observations further showed severe cell-wall erosion, lumen deformation, and local collapse, indicating that alkali treatment effectively reproduced typical microstructural features of degraded waterlogged wood. These chemical and microstructural changes subsequently led to marked changes in physical and mechanical properties. Mass loss increased with NaOH concentration and cycle number, while basic density decreased and maximum water content increased, indicating enhanced deterioration and water-holding capacity. Treated specimens also exhibited increased swelling and shrinkage rates and a substantial reduction in longitudinal compressive strength, with the most pronounced deterioration occurring under higher NaOH concentrations and repeated cycles. The study demonstrates that NaOH treatment can reproducibly simulate the physical, chemical, and microstructural characteristics of waterlogged archaeological wood, providing a reliable experimental model for studying wood degradation mechanisms and supporting conservation strategies. Full article

Thermal regulation of electrode materials offers an effective strategy for optimizing electrochemical kinetics in phosphate-based energy-storage systems. In this work, cobalt phosphate (Co₃(PO₄)₂) (CoP) electrodes were directly synthesized on nickel foam through a hydrothermal route and subsequently annealed at different temperatures (300, 400, and 500 °C) to investigate the influence of thermal treatment on structural evolution and supercapacitive behavior. X-ray diffraction confirmed the formation of crystalline CoP, while FESEM analysis revealed a strong dependence of morphology on annealing temperature, with CoP-400 exhibiting a well-developed interconnected plate-like architecture favorable for ion transport. XPS and elemental mapping verified the successful incorporation and uniform distribution of Co, P, and O species. Electrochemical investigations demonstrated that annealing temperature critically governs charge-storage behavior, ion diffusion, and mass transport properties. Among all electrodes, CoP-400 exhibited the best electrochemical performance, delivering a high areal capacitance of 28.62 F/cm² at 20 mA/cm², together with the highest ionic diffusion coefficient, lowest equivalent series resistance (0.39 Ω), and dominant diffusion-controlled charge-storage contribution (89%). Furthermore, CoP-400 retained 84.44% capacitance after 12,000 cycles. An asymmetric supercapacitor assembled using CoP-400//AC achieved an areal capacitance of 302 mF/cm², an energy density (ED) of 0.094 mWh/cm², and excellent cycling stability. These findings highlight annealing-engineered CoP as a promising electrode material for high-performance asymmetric supercapacitors. Full article

Background: 5-(3′,4′-Dihydroxyphenyl)-γ-valerolactone (DHPV) is a postbiotic gut microbiota-derived flavanol metabolite with reported anti-inflammatory activity. Despite growing interest in its potential dermatological applications, its pharmaceutical properties and suitability for topical delivery have not been systematically investigated. This study aimed to perform the first comprehensive preformulation and formulation-oriented evaluation of DHPV and to develop stable topical ointment formulations suitable for further dermatological research. Methods: The physicochemical properties of DHPV were characterized using powder X-ray diffraction (PXRD), Fourier-transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), quantitative solubility assessment, and excipient compatibility studies. Based on the obtained preformulation data, two anhydrous ointment formulations containing DHPV were developed. The formulations were evaluated for homogeneity, rheological behavior, chemical stability under accelerated storage conditions, and in vitro drug release performance. Results: DHPV was identified as a crystalline compound with heterogeneous particle morphology and limited aqueous solubility. Quantitative solubility studies demonstrated the highest solubility in PEG 300 and glycol-based solvents. Compatibility testing revealed increased impurity formation in hydrophilic environments, whereas lipophilic excipients provided improved chemical stability. Both ointment formulations exhibited acceptable physical characteristics and maintained DHPV stability throughout accelerated storage. However, marked differences in release behavior were observed. The lipid–wax formulation showed significantly higher release rates, lower variability, and more reproducible release profiles than the petrolatum-based reference formulation, indicating more efficient diffusion of DHPV from the semisolid matrix. Conclusions: The physicochemical characteristics of DHPV strongly influence formulation design and performance. Anhydrous lipid-based systems provide a favorable environment for maintaining DHPV stability, while formulation composition significantly affects drug release. The developed lipid–wax formulation represents a promising platform for future skin permeation, pharmacodynamic, and efficacy studies. Full article

This study examines the nature of enzymatic degradation of polyethylene terephthalate (PET) films mediated by a novel recombinant LCC^ICCG PETase enzyme preparation based on P. verruculosum fungus. The investigation was conducted using amorphous PET samples and PET samples with varying degrees of crystallinity as substrates for PETase-catalyzed hydrolysis under different temperature and pH conditions. Mechanical testing revealed that enzymatic treatment reduced the yield stress by 20–25%, tensile strength by approximately twofold, and elongation at break by 5–10 times, while the deformation mechanism remained unchanged. Enzymatic degradation under acidic conditions was ineffective, whereas increasing the pH to 9–10 markedly accelerated PET degradation and the associated deterioration of mechanical properties. Thermal analysis (TGA, DSC) and microscopy (optical and scanning electron microscopy) demonstrated that degradation was localized at the polymer surface, leading to the formation of cavities, cracks, and submicron-sized pores rather than bulk material disintegration. An inverse correlation was observed between PET crystallinity and susceptibility to enzymatic degradation: samples with crystallinity below 13% could be almost completely degraded, whereas samples with crystallinity above 30% exhibited little or no measurable weight loss over the same period. Low-crystallinity PET underwent rapid degradation accompanied by a transient increase in crystallinity, while highly crystalline PET primarily accumulated surface defects that nevertheless caused a substantial loss of mechanical strength. Consequently, the experimental data obtained in this study provide useful information for understanding PET degradation and for future studies on enzymatic PET recycling. The systematization of feedstock characteristics and the elucidated patterns of enzymatic degradation will enable optimization of pretreatment, enzymatic hydrolysis, and monomer recovery process parameters, thereby facilitating the eventual production of secondary raw materials. Full article

Potato starch (Solanum spp.) undergoes structural and functional modifications during traditional Andean chuño production; however, the integrated effects of processing history, cultivar-associated characteristics, and field-based environmental conditions remain insufficiently characterised. This study investigated the effects of chuño processing on the compositional, pasting, morphological, molecular, and crystalline properties of starches isolated from three potato cultivars (Condor Imilla, Luk’i Turno, and Dutch Désirée). Native and chuño starches were characterised by amylose quantification, viscoamylography, scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and X-ray diffraction (XRD), together with severe thermal treatment to evaluate structural stability. Chuño processing was associated with a reduction in amylose content across all cultivars (6.9–23.4%) and an increase in gelatinisation onset temperature of approximately 21.5% (from ~65 °C to ~79 °C). Peak viscosity decreased substantially after processing (457.5–1110 BU to 194.5–442.5 BU), while breakdown values remained close to zero, indicating increased resistance to viscosity loss during heating. SEM analysis revealed changes in granule morphology and size distribution associated with chuño processing and subsequent thermal treatment, with more pronounced reductions in granule size observed in Condor Imilla and Luk’i Turno than in Dutch Désirée. FT-IR analysis demonstrated modifications in short-range molecular organisation without the appearance of new functional groups, indicating structural reorganisation rather than chemical transformation. XRD analysis confirmed that all starches retained the native B-type crystalline polymorph after chuño processing, although reductions in diffraction intensity and peak definition indicated decreased long-range structural order. Severe thermal treatment eliminated detectable crystalline order in all samples, producing predominantly amorphous diffraction profiles. Overall, chuño processing was associated with reduced swelling capacity, lower paste viscosity, enhanced thermal stability, and multiscale structural reorganisation while preserving the fundamental B-type polymorph. Given that the plant material originated from distinct agroecological environments and that traditional chuño production involved a variable number of processing cycles, the observed differences should be interpreted as integrated responses of starch systems to processing history and material characteristics rather than strictly genotype-driven effects. These findings highlight the potential of chuño as a naturally modified starch system with distinctive technological properties. Full article