Search Results (12,200)

This paper examines the use of sheep wool and recycled aggregates (recycled concrete aggregate, reclaimed asphalt aggregate, recycled brick aggregate) in mortars. Nine cement mortars were prepared: a reference mortar with natural aggregate and no fibers, and eight mortars with 30% recycled aggregate, either fiber-free or micro-reinforced with 0.1% by mass of sheep wool fibers. The study investigates the effects of these components on the workability, mechanical properties, and microstructure of mortars. Micro-reinforcing mortars with sheep wool fibers or partially replacing natural aggregate with recycled aggregates reduces workability by up to 32%. Mortars with recycled concrete and recycled brick aggregates showed increased compressive and flexural strength compared to the reference mortar. The combined formulation (recycled brick with sheep wool micro-reinforcement) achieved the highest compressive strength, increasing by 24.3% while maintaining excellent flexural performance. Three-point bending tests with displacement control revealed improved post-crack behavior and greater ductility in fiber micro-reinforced specimens compared to those without fibers. The results support the use of sheep wool fibers in mortars, demonstrate the satisfactory performance of recycled aggregates, and indicate promising potential for formulations combining sheep wool fiber and recycled aggregate as sustainable and waste-reducing alternatives in mortars. Full article

With the acceleration of industrialization, the problems of water resource pollution and shortage caused by oil spills and industrial wastewater discharge have become increasingly severe, posing a major threat to ecological sustainable development. Therefore, efficient oil–water separation technology has become a key breakthrough to alleviate this crisis. In this study, Janus membranes with asymmetric wettability were prepared by layer-by-layer electrospinning. The influence of the thickness ratio between the hydrophobic layer and the hydrophilic layer on the mechanical properties, separation flux, and oil–water mixture efficiency of the Janus membranes was examined, and an optimized membrane configuration was determined: the optimal thickness ratio between hydrophobic and hydrophilic layers was 4:6. Under these conditions, the fracture stress of the fiber membranes reached 99% MPa, the fracture strain was 55.63 ± 4.77%, the separation flux values were 1888.22 and 1042.66 L m⁻² h⁻¹ for the oil–water mixture and water-in-oil emulsion, respectively, with the separation efficiencies all exceeding 99%. After 50 cycles of separation for two different oil-in-water emulsions, the separation flux and separation efficiency of the optimal sample remained relatively stable, demonstrating strong practicability. In general, the Janus fiber membranes met the expected requirements, laying a good foundation for future applications in oil–water separation, floating oil collection in water, and other fields. Full article

This study evaluated the physicochemical, antioxidant, and sensory properties of marshmallows enriched with tomato pomace (Lycopersicon esculentum), a by-product rich in fiber and bioactive compounds. Formulations with 0–6% pomace (Control, P1–P3) were analyzed during 20 days of storage. Tomato pomace addition increased crude fiber (from 0.00% to 0.42%) and protein (from 4.62% to 7.05%), while lipid and ash contents remained low (<0.15% and <0.90%, respectively). Carbohydrates ranged around 57–64 g/100 g, resulting in energy values near 270 kcal/100 g. Antioxidant activity (DPPH) increased from 34% in the control to 44% in enriched samples, confirming the contribution of polyphenols and carotenoids. Sensory evaluation (n = 20, 10-point scale) showed good overall acceptability, with enriched samples maintaining color and texture during storage. The results demonstrate that tomato pomace enhances the nutritional and antioxidant profile of marshmallows without negatively affecting sensory quality, supporting its use as a functional ingredient in confectionery formulations. Full article

Mango peels have great potential for upcycling in the food industry. This study addressed important knowledge gaps regarding mango peel drying, namely, the effect of drying on mango peels’ bound phenolics, and the impact of prior freezing on the composition of hot air-dried mango peels. Hence, the effect of freeze drying (FD) (0.10 mbar; −63 °C (condenser temperature); 25 °C (shelf temperature); 96 h), hot air drying (HAD) (65 °C; 48 h), and HAD preceded by freezing (FZ + HAD) (−20 °C; 30 days) on mango peels’ composition, antioxidant capacity, and technological properties was evaluated. Drying did not affect fiber content; however, it caused slight modifications in carbohydrate composition of fiber. Regarding antioxidant compounds, FD, HAD, and FZ + HAD reduced vitamin C by 9%, 53%, and 71%, respectively. FD preserved all free phenolics, while HAD and FZ + HAD decreased most of them, with reductions ranging from 20 to 42% and 17 to 71%, respectively. However, FD, HAD, and FZ + HAD reduced 9, 2, and 6 of the 10 bound phenolics identified, respectively, and decreased their antioxidant capacity. Finally, all identified carotenoids were reduced by FZ + HAD, whereas FD and HAD decreased only violaxanthin. Regarding technological properties, FD showed the highest and lowest oil and water absorption capacities. In conclusion, these findings demonstrated that prior freezing exacerbated the loss of antioxidants during HAD. Full article

This study presents the development and mechanical characterization of a full-scale helmet manufactured from a polyester matrix composite reinforced with woven jute fabric using vacuum infusion. Laminates with two and four reinforcement layers were produced and assembled using four joining configurations: seamless, stitched, bonded, and hybrid (bonded + stitched). Tensile tests were performed according to ASTM D3039, while frontal and lateral compression tests followed ABNT NBR 7471, aiming to evaluate the influence of laminate thickness and joining strategy on mechanical performance. In tension, the seamless configuration reached maximum loads of 0.80 kN (two layers) and 1.60 kN (four layers), while the hybrid configuration achieved 0.79 kN and 1.43 kN, respectively. Stitched and bonded joints showed lower strength. Under compression, increasing the laminate thickness from two to four layers reduced frontal elongation from 15.09 mm to 9.97 mm and lateral elongation from 13.73 mm to 7.24 mm, corresponding to stiffness gains of 50.3% and 87.3%, respectively. Statistical analysis (ANOVA/Tukey, α = 0.05) confirmed significant effects of thickness and joint configuration. Although vacuum infusion is a well-established process, the novelty of this work lies in its application to a full-scale natural-fiber helmet, combined with a systematic evaluation of joining strategies and a direct correlation between standardized tensile behavior and structural compression performance. The four-layer hybrid laminate exhibited the best balance between strength, stiffness, and deformation capacity. Full article

Predicting the transverse tensile properties of unidirectional CFRP plies is often based on micromechanical representative volume elements (RVEs) with circular fiber cross-sections, whereas microscopic observations show pronounced ellipticity and size variability in actual fibers. A two-dimensional plane-strain micromechanical framework with elliptical fiber cross-sections is developed as a virtual testing tool to quantify how fiber volume fraction, cross-sectional aspect ratio and statistical fluctuations in the semi-minor axis influence the transverse tensile response. Random RVEs are generated by a hard-core random sequential adsorption procedure under periodic boundary conditions and a minimum edge-to-edge gap constraint, and the fiber arrangements are validated against complete spatial randomness using nearest-neighbor statistics, Ripley’s K function and the radial distribution function. The matrix is described by a damage–plasticity model and fiber–matrix interfaces are represented by cohesive elements, so that high equivalent-stress bands in matrix ligaments and the associated crack paths can be resolved explicitly. Parametric analyses show that increasing fiber volume fraction raises the transverse elastic modulus and peak stress by thinning matrix ligaments and promoting longer, more continuous high-stress bands, while the cross-sectional aspect ratio redistributes high stress among ligaments and adjusts the balance between peak strength and the degree of failure localization. The observed size variability is represented by modeling the semi-minor axis as a normal random variable; a larger variance mainly leads to a reduction in transverse peak stress through stronger stress localization near very thin ligaments, whereas the elastic slope and the strain at peak stress remain almost unchanged. The proposed framework thus provides a statistically validated and computationally efficient micromechanical basis for microstructure-sensitive assessment of the transverse behavior of UD-CFRP plies with non-circular fiber cross-sections. Full article

This study investigates the reuse of mechanically recycled polyester–glass thermoset scraps (PS) as fillers in LDPE and HDPE matrices at 10–50 wt.% loading. Composites were produced through mechanical size reduction, single-screw extrusion, and compression molding without compatibilizers, and their mechanical and microstructural properties were systematically evaluated. LDPE composites exhibited a notable stiffness increase, with tensile modulus rising from 318.8 MPa (neat) to 1245.6 MPA (+291%) and tensile strength improving from 9.50 to 11.45 MPa (+20.5%). Flexural performance showed even stronger reinforcement: flexural modulus increased from 0.40 to 3.00 GPa (+650%) and flexural strength from 14.5 to 35.6 MPa (+145%). HDPE composites displayed similar behavior, with flexural modulus increasing from 1.2 to 3.1 GPa (+158%) and strength from 34.1 to 45.5 MPa (+33%). Surface-treated fillers provided additional stiffness gains (+36% in sPL4; +33% in sPH3). Impact strength decreased with loading (LDPE: −51%, HDPE: −61%), though surface treatment partially mitigated this (+14–19% in LDPE; +13% in HDPE). Density increased proportionally (PL: 0.95 → 1.20 g/cm³, PH: 0.99 → 1.23 g/cm³), while moisture uptake remained low (≤0.25%). Optical and SEM analyses indicated increasingly interconnected fiber networks at high loadings, driving stiffness and fracture behavior. Overall, PS-filled polyolefins offer a scalable route for converting thermoset waste into functional semi-structural materials. Full article

Lignocellulosic bio-based materials, such as wood, biocomposites, and natural fibers, exhibit desirable structural properties. This comprehensive review emphasizes the foundational and latest advancements in bioinspired improvement strategies, such as direct mineralization, biomineralization, lignocellulosic nanomaterials, protein-based treatments, and metal-chelating processes. Significant focus was placed on biomimetics, emulating natural protective mechanisms, with discussions on relevant topics including hierarchical mineral deposition, free-radical formation and quenching, and selective metal ion binding, and relating them to lignocellulosic bio-based material property improvements, particularly against fire and fungi. This review evaluates the effectiveness of different bioinspired processes: mineralized and biomineralized composites improve thermal stability, nanocellulose and lignin nanoparticles provide physical, thermal, and chemical barriers, proteins offer biochemical inhibition and mineral templating, and chelators interfere with fungal oxidative pathways while simultaneously improving fire retardancy through selective binding with metal ions. Synergistic approaches integrating various mechanisms could potentially lead to long-lasting and multifunctional protection. This review also highlights the research gaps, challenges, and potential for future applications. Full article

Utilizing forestry and agricultural byproducts like wood and hemp residues advance sustainable additive manufacturing (AM), while reducing material costs. This study investigated the development and characterization of wood–sodium silicate composites incorporating hemp hurd and hemp fibers for AM applications. Formulations varied by wood fiber type (unsifted, 40 mesh, and pellet), sodium silicate concentration (50–60 wt%), and hemp hurd content (0–15 wt%). Properties evaluated include particle size and bulk density of the constituent materials, rheological behavior, extrusion performance, composite bulk density, and flexural and compressive strengths. Rheology and extrusion were largely influenced by the liquid content. Mixtures with low liquid content (50 wt% sodium silicate) had high motor power and low viscosity. As liquid content increased, motor power decreased, while viscosity increased up to 55 wt% and then decreased at 60 wt%. Mechanical properties correlated with particle size, where finer particles enhanced strength. A cost analysis was conducted using raw material prices to determine the economic feasibility of each formulation. Finally, the formulations were evaluated based on strength-to-cost ratios, extrudability and processability. The formulation with pellet wood fibers, 55 wt% sodium silicate, and 10 wt% hemp hurd achieved a high ratio of 73.0 MPa/$ while maintaining low motor power. This formulation offered additional benefits which are discussed qualitatively. Full article

Polyester fibers are extensively used in textiles, packaging, and industrial applications due to their durability and excellent mechanical properties. However, high-crystallinity polyester fibers represent a major challenge in plastic waste management due to their resistance to biodegradation. This study evaluated the biodegradation potential of environmental Bacillus isolates, obtained from mold-contaminated black bean plastic bags, toward polyethylene terephthalate (PET) and industrial-grade polyester fibers under mesophilic conditions. Among thirteen isolates, five (Bacillus altitudinis N5, Bacillus subtilis N6, and others) exhibited measurable degradation within 30 days, with mass losses up to 5–6% and corresponding rate constants of 0.04–0.05 day⁻¹. A combination of complementary characterization techniques, including mass loss analysis, scanning electron microscopy (SEM), gel permeation chromatography (GPC), and gas chromatography/mass spectrometry (GC/MS), together with Fourier-transform infrared spectroscopy (FTIR), thermogravimetric/differential scanning calorimetry (TGA/DSC), and water contact angle (WCA) analysis, was employed to evaluate the biodegradation behavior of polyester fibers. Cross-analysis of mass loss, surface morphology, molecular weight reduction, and degradation products suggests a surface erosion-dominated degradation process, accompanied by ester-bond hydrolysis and preferential degradation of amorphous regions. FTIR, TGA/DSC, and WCA analyses further reflected chemical, thermal, and surface property changes induced by biodegradation rather than directly defining the degradation mechanism. The findings highlight the capacity of mesophilic Bacillus species to partially depolymerize polyester fibers under mild environmental conditions, providing strain resources and mechanistic insight for developing low-energy bioprocesses for polyester fiber waste management. Full article

The growing demand for gluten-free bakery products requires the development of formulations that overcome their typical technological and nutritional limitations. Using fruit by-products as natural fiber sources, in combination with xanthan gum (XG), supports a sustainable ingredient strategy that improves gluten-free product quality. This study investigated the effect of apple pomace (AP) (5% and 10%) and XG (1%) on the technological properties, texture profile, nutritional composition, and sensory acceptance of gluten-free muffins. Six formulations were prepared by partially replacing maize flour with AP and/or adding XG. AP (5–10%) reduced muffin height and volume compared with the control, whereas 1% XG increased muffin height by 11.16% and raised volume and specific volume by 38.46% and 36.11%, respectively. XG significantly decreased hardness compared with the control, while the effect of AP on texture was concentration-dependent: 5% AP reduced hardness, whereas 10% AP did not further improve softness. Combined use of AP and XG resulted in complementary effects, improving structural properties while increasing dietary fiber content. The muffins supplemented with AP were acceptable, and their overall acceptability did not differ significantly among the tested formulations. Overall, the results demonstrate that incorporating AP together with XG enhances both the technological and nutritional quality of gluten-free muffins, supporting the valorization of fruit-processing by-products in functional bakery applications. Full article

Numerical simulation of the electrical conductivity of carbon fiber-reinforced asphalt concrete is essential for understanding its electrical behavior, yet research in this area remains limited. This study prepared six groups of Marshall specimens with carbon fiber (CF) contents of 0.1 wt%, 0.2 wt%, 0.3 wt%, 0.4 wt%, 0.5 wt%, and 0.6 wt%. The resistivity and asphalt concrete (AC) impedance spectra were measured to analyze the effect of fiber content on electrical performance. Nyquist diagrams were fitted to establish an equivalent circuit model, and a representative volume element (RVE) finite element model was developed. The Generalized Effective Medium (GEM) equation was employed to fit the resistivity data. The results show that the resistivity exhibits a two-stage characteristic—an abrupt decrease followed by stabilization, with an optimal CF content range of 0.2–0.4 wt%. Among the equivalent circuit parameters, the contact resistance (R₁) and tunneling resistance (R₂) significantly decreased, the growth of interface capacitance (C₁) slowed, the constant phase element Z_Q increased, and the non-monotonic change of volume resistance (R₃) reflected the heterogeneity of the internal void distribution of the material. The finite element numerical solution for resistivity, derived from the GEM equation, aligns well with experimental values, validating the proposed simulation approach. Full article

With the continuous increase in well depth and the gradual depletion of formation energy, the pump-setting depths in rod-pumped wells have increased significantly, leading to higher suspension loads at the pumping unit. The application of glass fiber-reinforced plastic (FRP) sucker rods can effectively reduce suspension loads due to their low density and high tensile strength. However, the mechanical performance of FRP rods is highly sensitive to temperature, which poses challenges for their application in deep and high-temperature wells. In FRP–steel hybrid sucker-rod string design, the influence of temperature—particularly on FRP rods—must therefore be carefully considered to prevent failures such as rod parting or coupling separation. This study systematically investigates the effects of temperature on the mechanical properties of FRP sucker rods, including elastic modulus, flexural shear strength, and tensile strength. Based on the operating characteristics of sucker-rod pumping systems and established design criteria, a temperature-aware design methodology for FRP–steel hybrid rod strings is developed and implemented in dedicated design software. The proposed approach enables rational determination of the FRP–steel partition depth under thermal constraints while satisfying mechanical safety requirements. A field case study is conducted to validate the design results, demonstrating that the software provides reliable and practical guidance for hybrid rod-string design in deep wells. Full article

As global interest in sustainable nutrition grows, algae have emerged as a promising functional food resource. This review analyzes the nutritional value of edible algae, with a particular focus on protein-rich microalgae, and synthesizes current clinical evidence regarding their health benefits. Algae have been demonstrated to provide a broad spectrum of physiologically active nutrients, encompassing a range of vitamins and minerals as well as polyunsaturated fatty acids, antioxidant molecules and various bioactive compounds including dietary fiber. These nutrients have been linked to improved cardiovascular and metabolic health, enhanced immune function, and anti-inflammatory effects. A particular emphasis is placed on algal proteins as a novel alternative to traditional dietary proteins. Genera such as Spirulina and Chlorella offer high-quality, complete proteins with amino acid profiles and digestibility scores comparable to those of animal and soy proteins, thereby supporting muscle maintenance and overall nutritional status. Recent clinical studies have demonstrated that the ingestion of microalgae can stimulate muscle protein synthesis and improve lipid profiles, blood pressure, and inflammation markers, indicating functional benefits beyond basic nutrition. Algal proteins also contain bioactive peptides with antioxidative properties that may contribute to positive outcomes. This review synthesizes current studies, which demonstrate that algae represent a potent, sustainable protein source capable of enhancing dietary quality and promoting health. The integration of algae-based products into plant-forward diets has the potential to contribute to global nutritional security and long-term public health. However, the available clinical evidence remains heterogeneous and is largely based on small, short-term intervention studies, with substantial variability in algae species, processing methods and dosages. Consequently, while the evidence suggests the possibility of functional effects, the strength of the evidence and its generalizability across populations remains limited. Full article

Almond skin is an abundant by-product of almond processing and is recognized for its rich content of dietary fiber, polyphenols, and unsaturated fatty acids along with potential health benefits. This study aimed to evaluate the nutritional composition, prebiotic potential, and microbiota modulation properties of dehydrated almond skin, including its use in 3D-printed functional biscuits. Nutritional analysis revealed high dietary fiber (62.6%) and substantial antioxidant capacity linked to polyphenols. Almond skin supplementation with a concentration ranging from 2.5% to 5.0% significantly enhanced the viability of various probiotic strains during storage, extending their shelf life. Two biscuit formulations, with and without almond skin, were produced and subjected to simulated gastrointestinal digestion (INFOGEST protocol) followed by in vitro fermentation using a minimal gut microbiota model (Bifidobacterium longum, Lactobacillus rhamnosus, Bacteroides caccae, Escherichia coli, Segatella copri, and Clostridioides difficile). Results demonstrated that biscuit enriched with almond skin selectively promoted the growth of beneficial bacteria such as B. longum and L. rhamnosus (from 6.9 to 8.5 log cfu/mL and from 7.8 to 9.0 log cfu/mL, respectively) while suppressing pathogens including C. difficile and E. coli. Moreover, enriched biscuits retained higher polyphenol content and exhibited a favorable macronutrient profile. These findings support the valorization of almond skin as a sustainable functional ingredient offering prebiotic effects and probiotic viability protection, with promising applications in personalized nutrition and gut health management. Further in vivo studies and clinical trials are necessary to confirm these effects and optimize formulations for commercial use. Full article