Search Results (618)

Concrete is one of the most important and most widely used materials for construction activities around the world. However, it has inherent deficiencies, e.g., brittleness, low impact resistance, low tensile strength, low fire resistance, low durability, and lower resistance to crack formation. Fibers and waste materials of different types are added as partial replacement of cement and aggregates in concrete to improve performance properties and reduce environmental pollution. In the present study, a thorough review of the use of various types of fibers with high and low elastic moduli in concrete to improve mechanical performance and reduce environmental pollution issues has been conducted. This review paper also provides comprehensive information on the different types of waste materials, e.g., biodegradable and non-biodegradable, which are used in concrete. The use of waste materials in concrete reduces the amount of waste sent to landfill and, in addition, improves some mechanical properties of concrete. This review is aimed at evaluating and understanding the strengths and weaknesses of fiber-reinforced concrete by using SWOT (Strengths, Weaknesses, Opportunities, Threats) analysis. Moreover, this study also concluded that carbon fiber-reinforced concrete proves to be stronger and more durable but more expensive than other fibers. An ideal percentage of natural origin fibers used in concrete can greatly improve the mechanical performance. This study also discussed that waste from polymeric materials can be used in concrete as a partial replacement of cement and other components, e.g., coarse aggregates. It can be inferred that the optimum content of fibers that gives effective results is about 1%, and the reinforcement of concrete with different varieties of wastes as a replacement for fine aggregates should not be more than 2%. Parametric optimization of fiber content will be necessary for the best possible combination of performance properties. Full article

The rapid expansion of carbon-fiber-reinforced polymer (CFRP) applications in aerospace, automotive, and energy sectors has intensified concerns over end-of-life waste and the absence of efficient recycling solutions. Plasma-assisted solvolysis has emerged as a promising hybrid approach, combining oxidative chemical treatment with plasma activation to accelerate matrix degradation. In this study, CFRP cylinders (6.4 cm height, 5.5 cm internal, and 6.0 cm external diameter) were processed in a closed-loop plasma solvolysis system under varied operational parameters, including plasma power, plasma gas composition, and nitric acid concentration. The mechanical performance of the recovered carbon fibers was assessed through single-fiber tensile and microbond tests, evaluating both tensile and interfacial properties. In most cases, the recycled fibers retained—or even exceeded—the tensile strength of their virgin counterparts, reaching up to 1.49 times that of the virgin fibers. Young’s modulus, though more variable, ranged from 0.48 to 1.67 times the reference value depending on treatment conditions. Elongation at break generally increased, particularly in the 24K (24,000-filaments) fiber sets, suggesting improved surface ductility. Weibull statistical analysis indicated higher consistency in 3K (3000-filaments) fiber batches compared to 24K, whereas interfacial shear strength was moderately retained across conditions. Overall, balanced plasma and acid conditions enabled efficient fiber recovery with high strength and interfacial performance, validating plasma-assisted solvolysis as a viable route for recovering high-performance fibers suitable for structural reuse, in alignment with circular economy principles. Full article

A carbon-supported palladium-containing polysiloxane macrocatalyst (Pd-PDMS) was developed for pharmaceutical-grade cross-coupling reactions. The catalyst demonstrates exceptional year-long stability at room temperature while maintaining full catalytic activity. Pd-PDMS efficiently promotes three pharmaceutically relevant reactions: Suzuki coupling (80% yield), copper-free Sonogashira coupling (90% yield at 55 °C), and Heck coupling (80% yield at 90 °C). The copper-free Sonogashira protocol eliminates toxic copper cocatalysts, phosphine ligands, and organic bases while operating under mild conditions. Most significantly, palladium contamination in products reaches ultra-low levels of 22 ppb (Sonogashira, Suzuki) and 167 ppb (Heck), representing a 60–450-fold improvement over European Medicines Agency requirements (10 ppm). The catalyst exhibits excellent recyclability without activity loss over multiple cycles, with simple washing protocols between uses. Scanning electron microscopy and X-ray photoelectron spectroscopy confirmed uniform Pd-PDMS coating on carbon fibers, while density functional theory calculations revealed specific coordination interactions between the palladium complex and carbon support at 3.26 Å distance. This convergence of pharmaceutical-grade metal contamination control, exceptional stability, and multi-reaction versatility establishes a significant advancement for sustainable cross-coupling catalysis in pharmaceutical applications. Full article

Carbon fibers derived from carbonized and activated polyacrylonitrile (CFPAN) were sequentially brominated and subsequently functionalized with selected primary and secondary amines to engineer a directional electromagnetic (EM) response. Besides bromine incorporation, bromination introduced oxygen-containing surface groups (e.g., carboxyl, lactone), enabling nucleophilic substitution by amines. Surface characterization (SEM-EDS, FTIR ATR) confirmed successful amine grafting, while thermal analysis (TGA, TPD MS) revealed increased weight loss in the 150–450 °C range due to the decomposition of covalently bonded nitrogen- and oxygen-containing moieties, evidencing strong surface functionalization. Microwave characterization in the X-band (8.2–12.4 GHz) demonstrated that functionalization strongly influences the EM response of CFPAN fibers. The measured reflection coefficient varied from −1.0 to −2.5 dB for sulfonylethylenediamine (SuEn)-functionalized fibers and from −2.0 to −4.0 dB for ethylenediamine (En)-treated ones, depending on frequency and fiber orientation. The frequency-averaged absorption coefficient of pure CFPAN amounted to 32–41%, with absorption maxima and minima corresponding to orientations differing by 90°. SuEn modification decreased absorption to 21–35%, while En functionalization enhanced it to 32–51%. Pure CFPAN exhibited the lowest absorption anisotropy (factor 1.28), whereas piperazine- and En-modified samples showed the highest anisotropy (1.57 and 1.59, respectively). Across all compositions, the attenuation constant remained within 1.5–4.5 mm⁻¹. The observed anisotropic behavior is governed primarily by orientation-dependent variations in characteristic impedance and, to a lesser extent, by anisotropic attenuation constants. Such tunable anisotropy is particularly advantageous for EM shielding textiles, where fiber alignment can be tailored to enhance interaction with polarized fields. Among the tested amines, En-functionalized CFPAN exhibited the highest nitrogen content (up to 10.1 at%) and the most significant enhancement in microwave absorption, positioning it as a promising candidate for advanced orientation-sensitive shielding applications. Full article

This study explores the potential of a bio-based thermosetting adhesive system incorporating recycled fillers to enhance structural bonding applications while promoting sustainability. Diglycidylether of vanillyl alcohol (DGEVA) was selected as the resin matrix due to its favorable thermomechanical properties and low moisture absorption. To improve mechanical performance and support circular economy principles, recycled carbon fibers (RCFs) and mineral wool (MW) were integrated into the adhesive formulation in varying proportions (10, 30, and 50 phr). A cationic thermal initiator, ytterbium (III) trifluoromethanesulfonate (YTT), was used to permit polymerization. Comprehensive characterization was performed to assess the curing behavior, thermal stability, and mechanical performance of the adhesive. FTIR spectroscopy monitored the polymerization process, while DSC and dynamic DSC provided insights into reaction kinetics, including activation energy, and curing rates. The mechanical and thermomechanical properties were evaluated using dynamic mechanical thermal analysis (DMTA) and shear lap testing on bonded joints. Additionally, SEM imaging was employed to examine fillers’ morphology and joint interfaces. The results indicated that increasing filler content slowed polymerization and raised activation energy but still permitted high conversion rates. Both RCF- and MW-containing formulations exhibited improved stiffness and adhesion strength, particularly in CMC joints. These findings suggest that DGEVA-based adhesives reinforced with recycled fillers offer a viable and sustainable alternative for structural bonding, contributing to waste valorization and green material development in engineering applications. Full article

Fiber-based and fabric batteries signify a groundbreaking development in energy storage, allowing for the straightforward incorporation of power sources into wearable fabrics, intelligent apparel, and adaptable electronics. In this study, we introduce a novel strategy for one-step fabrication of a flexible lithium titanate oxide (Li₄Ti₅O₁₂, LTO) anode directly on a copper current collector via electrospinning, eliminating the need for high-temperature post-processing. Based on our previous work with electrospun nanofiber cathodes and carbon-based current collector, we prepared the LTO electrode using polyethylene oxide (PEO) as a binder and carbon additives to enhance mechanical integrity and conductivity. LTO fiber mats detached from the current collector were found to endure multiple instances of bending, twisting, and folding without any structural damage. LTO/Li cells incorporating electrospun fiber LTO electrodes with 72 wt% active material loading deliver a high capacity of 170 mAh g⁻¹ at 0.05 C. In addition, they demonstrate excellent cycling stability with a capacity loss of only 0.01% per cycle over 200 cycles and maintain a capacity of 160 mAh g⁻¹ at 0.1 C. The scalability of the heat-treatment-free method for fabricating flexible LTO anodes, together with the improved mechanical durability and electrochemical performance, offers a promising route toward the development of next-generation flexible and wearable energy storage devices. Full article

Hericium coralloides is a valuable medicinal and edible mushroom renowned for its unique bioactive compounds. This study focuses on the isolation of a wild strain (SH001) exhibiting promising cultivation potential and health promoting properties. A wild fungal strain from the Tibetan Plateau was isolated and identified as a novel H. coralloides based on its morphological and molecular characteristics. The optimal growth conditions were found to be 30 °C, pH 7.0, fructose as the preferred carbon source, and yeast extract as the optimal nitrogen source. Nutritional analysis revealed that the fruiting bodies were rich in protein (15.4 g/100 g dry weight), dietary fiber (34.7 g/100 g dry weight), and minerals, while being low in fat (3.5 g/100 g dry weight). The most abundant amino acids were glutamic acid, followed by aspartic acid. The polysaccharides exhibited significant antioxidant activity, with ABTS⁺ scavenging comparable to that of Vitamin C (Vc), achieving a clearance rate of 96.95% at concentrations between 0.25–5.00 mg/mL. At a concentration of 5 mg/mL, the DPPH and OH radical scavenging activities reached their peak (83.77% and 67.31%, respectively), along with the highest iron ion reducing capacity (FRAP value: 4.43 mmol/L. Polysaccharides also exhibited notable anticancer activity, inhibiting HepG2 liver cancer cells and MDA-MB-468 breast cancer cells, with IC₅₀ values of 3.896 mg/mL and 2.561 mg/mL, respectively. This study demonstrates that wild H. coralloides can be successfully cultivated in vitro. In conclusion, the fruiting bodies possess substantial nutritional value, and the polysaccharides extracted from them show promising antioxidant and anticancer activities, particularly against HepG2 liver cancer cells and MDA-MB-468 breast cancer cells. Full article

Industrial air pollution, particularly acidic gases such as hydrogen chloride (HCl), poses serious environmental and health hazards. Here, hopcalite catalysts were introduced into activated carbon fibers via the impregnation process to enhance HCl capture. The Cu/Mn molar ratio was fixed at 1:1 while the Cu precursor loading was varied with the weight of Cu (Cu 0.04–0.1). Structural and surface modifications were examined using scanning electron microscope, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, inductively coupled plasma mass spectrometer, and Brunauer–Emmett–Teller analyses. Progressive CuMnOx deposition increased Cu and Mn contents up to 4 at.% and 3.7 at.%, respectively, but decreased the specific surface area from 1565.1 to 1342.7 m²/g owing to pore blocking. Fixed-bed breakthrough tests (50 ppm HCl, 1000 mL/min) showed that moderate catalyst addition (Cu 0.04) yielded the highest total removal (83.6%) and adsorption capacity (12,354.6 mg/g), benefiting from combined physical and catalytic chemisorption. Higher loadings (Cu 0.06–0.1) further reduced microporosity and led to lower removal efficiencies. These results demonstrate that an optimal CuMnOx level effectively promotes chemical adsorption without compromising the intrinsic microporous network of ACFs. Full article

This study aimed to develop a high-performance Modified Activated Carbon Fiber (ACF) filter for the effective removal of Volatile Organic Compounds (VOCs) generated in workplaces and for application in indoor VOCmitigation devices. ACF was modified with CuMnOx catalysts and evaluated for the removal of formaldehyde, acetaldehyde, and benzene. The modified ACF filter was prepared by introducing CuMnOx via an impregnation method using Cu(NO₃)₂⋅3H₂O and Mn(NO₃)₂⋅6H₂O precursors, followed by a crucial high-concentration oxygen plasma surface treatment (50 sccm gas flow) to effectively incorporate oxygen functional groups, thereby enhancing catalyst dispersion and activity. Characterization of the fabricated ACF/CuMnOx composite revealed that the optimized sample, now designated ACF-P-0.1 (representing both CuMnOx catalyst impregnation and O₂ plasma treatment), exhibited uniformly dispersed CuMnOx particles (<500 nm) on the ACF surface. This stability retained a high specific surface area (1342.7 m²/g) and micropore ratio (92.23%). H₂-TPR analysis demonstrated low-temperature reduction peaks at 140 °C and 205.8 °C, indicating excellent redox properties that enable high catalytic VOC oxidation near room temperature. The oxygen plasma treatment was found to increase the interfacial reactivity between the catalyst and ACF, contributing to further enhancement of activity. Performance tests confirmed that the ACF-P-0.1 sample provided superior adsorption–oxidation synergy. Benzene removal achieved a peak efficiency of 97.5%, demonstrating optimal interaction with the microporous ACF structure. For formaldehyde, a removal efficiency of 96.6% was achieved within 30 min, significantly faster than that of Raw ACF, highlighting the material’s ability to adsorb VOCs and subsequently oxidize them with high efficiency. These findings suggest that the developed ACF/CuMnOx composite filters can serve as promising materials for VOCs removal in indoor environments such as printing, coating, and conductive film manufacturing processes. Full article

This study presents a strut-and-tie modeling (STM) framework for reinforced concrete (RC) deep beams strengthened with intraply hybrid composites (IRCs), integrating comprehensive experimental data from beams with three different span lengths (1.0 m, 1.5 m, and 2.0 m). Although the use of fiber-reinforced polymers (FRPs) for shear strengthening of RC members is well established, limited attention has been given to the development of STM formulations specifically adapted for hybrid composite systems. In this research, three distinct IRC configurations—Aramid–Carbon (AC), Glass–Aramid (GA), and Carbon–Glass (CG)—were applied as U-shaped jackets to RC beams without internal transverse reinforcement and tested under four-point bending. All experimental data were derived from the authors’ previous studies, ensuring methodological consistency and providing a robust empirical basis for model calibration. The proposed modified STM incorporates both the axial stiffness and effective strain capacity of IRCs into the tension tie formulation, while also accounting for the enhanced diagonal strut performance arising from composite confinement effects. Parametric evaluations were conducted to investigate the influence of the span-to-depth ratio (a/d), composite configuration, and failure mode on the internal force distribution and STM topology. Comparisons between the STM-predicted shear capacities and experimental results revealed excellent correlation, particularly for deep beams (a/d = 1.0), where IRCs substantially contributed to the shear transfer mechanism through active tensile engagement and confinement. To the best of the authors’ knowledge, this is the first study to formulate and validate a comprehensive STM specifically designed for RC deep beams strengthened with IRCs. The proposed approach provides a unified analytical framework for predicting shear strength and optimizing the design of composite-strengthened RC structures. Full article

On-site curing of metakaolin (MK)- and granulated blast furnace slag (GBFS)-based geopolymer mortars remains a major bottleneck compared to thermal treatment for early strength development, and electrical curing is proposed here as a highly scalable and energy-efficient alternative technology. Geopolymer mortars with 0–100% MK/GBFS binder ratios were activated using sodium silicate (SS) and sodium hydroxide (SH) solutions of the following molarities: 6, 8, 10, 12, and 14 M. Steel fiber (SF), carbon fiber (CF), waste erosion wire (EW), and carbon black (CB) microfiller were incorporated to enhance the electro-conductive efficiency of the geopolymer matrix. Specimens were subjected to electrical curing under 10 V and 20 V AC and were compared with benchmarking under ambient conditions of 23 °C and thermal conditions of 70 °C. The findings established that the incorporation of fibers substantially boosted the level of conductivity and mechanical performance, with 28-day compressive strengths of up to 88.30 MPa (0.50% EW, 20 V) and flexural strengths of up to 22.24 MPa (0.50% CF, 7 days), exceeding the results of conventional curing in various instances. Microstructural studies based on well-bonded geopolymer gels with fibers indicated uniform geopolymerization through electrical curing without deleterious fiber–matrix interactions. A multi-criteria decision support approach (the HD method) based on 273 parameters established 0.50% CF, 0.75% SF, 0.75% EW, and 1.00% CB as the group-wise optima and chose 0.75% EW as the single-best performing combination. The findings confirm that electrical curing is a low-carbon, cost-effective, and field-adjustable curing technology with the potential to achieve target strength ratings, in line with the European Green Deal’s climate-neutral building material goals. Full article

To address grassland ecosystem degradation caused by mining disturbance and its severe threats to regional ecological security in alpine mining areas, this study systematically evaluated the synergistic effects of different application ratios of Effective Microorganisms inoculant and organic fertilizers on artificial grassland ecosystem functions in the Muli alpine mining region of the Qinghai-Tibet Plateau, based on field experiments conducted from 2022 to 2024. The results demonstrated significant improvements in production performance. The Y2E2 treatment (0.60 t·hm⁻² Effective Microorganisms inoculant + 20 t·hm⁻² organic fertilizer) exhibited optimal effects, with aboveground biomass increasing by 75.97% and 68.88% in 2023 and 2024, respectively, compared to the control (p < 0.05), while belowground biomass simultaneously increased by 36.05% and 35.53% (p < 0.05), showing a sustained upward trend. Nutritional quality was markedly enhanced, with the Y2E2 treatment consistently achieving the best performance across both years. Crude protein and ether extract contents increased by 46.18%~46.52% and 62.42%~63.25%, respectively (p < 0.05), while soluble sugar content rose significantly by 19.49%~20.56% (p < 0.05). Concurrently, crude ash and fiber fractions were significantly reduced. Soil physicochemical properties improved substantially, with the Y2E2 treatment in 2024 reducing soil pH and bulk density by 11.10% and 37.20%, respectively (p < 0.05), while increasing soil organic carbon, available nitrogen, and available potassium by 92.94%, 49.25%, and 96.08% (p < 0.05). Soil biological activity was significantly enhanced, as evidenced by increases of 78.33%, 55.69%, 55.87%, and 183.67% in β-glucosidase, dehydrogenase, urease, and acid phosphatase activities, respectively (p < 0.05), alongside rises of 117.64% and 94.78% in microbial biomass carbon and phosphorus (p < 0.05). Mechanistic analysis via structural equation modeling revealed strong positive direct effects of the Effective Microorganisms inoculant–organic fertilizer combination on forage yield (β = 0.27, p < 0.001) and nutritional quality (β = 0.73, p < 0.001). Principal component analysis (cumulative variance explained: 88.90%) further confirmed Y2E2 treatment superior performance in soil improvement, microbial function enhancement, and grassland productivity. In conclusion, the optimal remediation strategy for alpine mining grasslands was identified as the combined application of 0.60 t·hm⁻² Effective Microorganisms inoculant and 20 t·hm⁻² organic fertilizer. This approach drives ecosystem function restoration through a multidimensional synergistic mechanism involving soil physicochemical amelioration–microbial activity stimulation–nutrient supply optimization, providing both theoretical foundations and practical solutions for ecological restoration of degraded grasslands in similar regions. Full article

The rational design of multifunctional electrocatalysts requires synergistic integration of conductive scaffolds with redox-active components. Here, a hierarchical core–shell NiCo₂S₄ grown/anchored on Co₉S₈-loaded carbon nanofibers (NCS/CS/CNFs) was synthesized via an electrospinning and hydrothermal approach and systematically characterized. FESEM/TEM confirmed a core-shell nanofiber structure with a NiCo₂S₄ shell thickness of ~30–70 nm, increasing the fiber diameter to ~290 ± 30 nm, while BET analysis revealed a surface area of 24.84 m² g⁻¹ and pore volume of 0.042 cm³ g⁻¹, surpassing CS/CNFs (6.12 m² g⁻¹) and NCS (4.85 m² g⁻¹). XRD confirmed crystalline NiCo₂S₄ and Co₉S₈ phases, while XPS identified mixed Ni²⁺/Ni³⁺ and Co²⁺/Co³⁺ states with strong Ni-S/Co-S bonding, indicating enhanced electron delocalization. Electrochemical measurements in 1 M KOH demonstrated outstanding OER activity, with NCS/CS/CNFs requiring only 324 mV overpotential at 10 mA cm⁻², a Tafel slope of 125.7 mV dec⁻¹, and low charge-transfer resistance (0.33 Ω cm²). They also achieved a high areal capacitance of 1412.5 μF cm⁻² and maintained a stable current density for >5 h. For methanol oxidation, the composite delivered 150 mA cm⁻² at 0.1 M methanol, ~1.6 times that of CS and 1.3 times that of NCS, while maintaining stability for 18,000 s. This bifunctional activity underscores the synergy between conductive CNFs and hierarchical sulfides, offering a scalable route to durable electrocatalysts for water splitting and direct methanol fuel cells. Full article

The objective of this study was to investigate the adsorption of 11 azoles (tebuconazole, ketoconazole, econazole, miconazole, fluconazole, clotrimazole, climbazole, flutriafol, epoxiconazole, tiabendazole, and imazalil) on natural and waste-derived sorbents such as ceramsite, perlite, pumice, sawdust, coconut fibers, heavy oil fly ash (HOFA), activated carbon, and silica gel. The results of adsorption efficiency for most sorbents varied depending on the azole compounds and their concentration. The highest adsorption for all tested compounds was obtained for activated carbon and heavy oil fly ash, reaching about 100% in both tested concentrations (0.2 mg L⁻¹ and 0.02 mg L⁻¹). The HOFA material was characterized in terms of elemental analysis (CHNS), confirming the elemental contents of 52% C, 0.65% H, 0.4% N, and 2.3% S. The specific surface area of HOFA was 11.2 m² g⁻¹, and scanning electron microscopy (SEM) results showed the spherical yet porous nature of the particles. Furthermore, the calculated adsorption isotherms demonstrated that for most tested azoles, the Dubinin–Radushkevich (D-R) isotherm best fits the data, with R² = 0.93 or more, which is characteristic of porous carbon materials. The results highlight the significant potential of the tested HOFA sorbent for effectively removing azoles, as the tests performed showed that it was possible to remove these compounds with a concentration of up to 0.2 mg L⁻¹ within an hour. This is particularly important because HOFA is an easily accessible waste material. Furthermore, the adsorption of azoles will not increase the cost of HOFA disposal when using the standard procedures currently applied to this waste. Full article

JP-10 (exo-tetrahydrodicyclopentadiene) is a high-energy-density hydrocarbon broadly used in advanced aerospace propulsion as a regenerative cooling fluid; in this study, we aimed to clarify how fuel pressure affects its thermal degradation (oxidative and pyrolytic) in near-isothermal flowing reactor. Experiments were performed under oxidative conditions (wall temperature 623.15 K, p = 0.708–6.816 MPa) and pyrolytic conditions (wall temperature 793.15 K, p = 2.706–7.165 MPa); carbon deposits were quantified by LECO analysis, oxidation activity was assessed by temperature-programmed oxidation (TPO), and morphology was performed by FESEM and EDS. Results show that oxidative coking is minimal (5.37–14.95 μg·cm²) and largely insensitive to pressure in the liquid phase (1.882–6.816 MPa), whereas at 0.708 MPa (gas/phase-change conditions), deposition increases, implicating phase and local heat-transfer effects. Under oxidative conditions, deposits are predominantly amorphous carbon with a disordered structure, formed at relatively low temperatures, with only a few fiber-like metal sulfides identified by EDS. In contrast, under pyrolysis conditions, the deposits are predominantly carbon nanotubes, exhibiting well-defined tubular morphology formed at elevated temperatures via metal-catalyzed growth. The pyrolysis coking yield is substantially higher (66.88–221.89 μg·cm⁻²) and increases with pressure. The findings imply that the pressure influences the coking of JP-10 via phase state under oxidative conditions and residence time under pyrolytic conditions, while basic morphologies of coke deposits remain similar; operationally, maintaining the working pressure higher than the saturated vapor pressure can mitigate oxidation coking associated with phase transitions, and minimizing residence time can mitigate pyrolytic coking. Full article