Search Results (755)

This work presents a comparative study of micro- and nano-scale fillers in liquid composite molding processes, focusing on how particle size and morphology affect resin rheology, flow behavior, and filler filtration within fiber preforms. Glass microspheres and organo-modified montmorillonite were dispersed in epoxy resin and injected through glass-mat preforms at different fiber volume fractions (ranging from 0.27 to 0.47). Our study integrates rheological characterization, in situ flow-front tracking, unsaturated permeability analysis, thermogravimetric quantification of retained particles, and microstructural observations by SEM. Despite their smaller loading, nanoclay suspensions showed a markedly higher viscosity increase than microsphere systems, yet their permeability remained nearly unchanged. In contrast, microsphere-filled resins exhibited strong filtration at the flow inlet, density-driven settling near the lower tool face, and significant permeability loss. The results demonstrate that nano-fillers, although more viscous, maintain homogeneous distribution and flow continuity, whereas micro-fillers promote cake formation and local compaction. This controlled side-by-side comparison clarifies how filler size and shape govern filtration mechanisms in liquid composite molding (LCM), providing design guidelines for processing filled resin systems without compromising part quality. Full article

This paper presents the numerical modeling and experimental testing of steel-reinforced columns composed of three types of concrete: reinforced cement concrete (RCC), geopolymer concrete (GPC), and geopolymer concrete incorporating quarry rock dust (GPCD). GPC columns were produced using fly ash (FA) and furnace slag (SG) in equal proportions (50% each), with the addition of 0.75% steel fibers by volume. In GPCD columns, 20% of SG was replaced with quarry rock dust (QRD). A total of twenty columns (200 mm × 200 mm × 1000 mm), designed for a compressive strength of 40 MPa (fc’), were tested under static loading. The experimental data were validated using finite element (FE) modeling in ABAQUS, where the Concrete Damaged Plasticity (CDP) model was adopted to describe concrete behavior. Calibration of the FE model for the control specimen was carried out by adjusting viscosity parameters, dilation angles, shape factors, plastic potential eccentricity, stress ratios, and mesh sizes. The calibrated control model was then employed for comparative analysis and validation against experimental results. For concentrically loaded columns, the predicted axial load and axial and lateral deflection responses closely matched the experimental observations. However, for eccentrically loaded columns, the FE model over-predicted the load-carrying capacity as well as axial and lateral deflections. The experimental findings indicate that both GPC and GPCD columns exhibited lower load-carrying capacities compared to RCC columns; however, the inclusion of steel fibers enhanced their performance. Overall, the proposed FE model demonstrated a good agreement with experimental observations, providing a reliable framework for predicting the structural behavior of geopolymer-based columns. Full article

Semiconductor miniaturization demands stricter material uniformity. Core-shell nanofibers, promising for semiconductor packaging and flexible circuits, face application limits due to traditional coaxial electrospinning’s electric field instability—causing poor fiber diameter uniformity and challenges with high-viscosity and low-conductivity solutions. To address this, airflow-assisted coaxial electrospinning leveraged airflow-electric field synergy to enhance fiber stretching. COMSOL Multiphysics 6.4 simulated the influence of different inner diameters of the air flow nozzles on the air flow field, while the response surface method optimized parameters. At 10 kPa air pressure, 16.71 kV voltage, and a gas nozzle inner diameter of 3.42 mm, nanofibers showed regular morphology with a diameter coefficient of variation as low as 9.2%. This study enables stable preparation of highly uniform core-shell nanofibers, providing key process support for their large-scale semiconductor application and advancing flexible electronics and photodetection. Full article

Compound sugars (Cs) and creatine (Cr) have the potential to enhance exercise endurance; however, the mechanisms underlying their effects and the stability of their formulations still require further investigation. This study investigated the effects of Cs and Cr supplementation on exercise performance in C57BL/6 mice, as well as the processing properties of Cs and Cr powder. The exhaustion time, serum fatigue indices, creatine contents, the morphology of muscle tissue in mice were determined. The results demonstrated that combined supplementation of sugar and creatine (Cs-Cr, Cs 6.2 mg/g + Cr 1.0 mg/g) could significantly increase exhaustion time and forelimb grip strength and reduce the levels of lactate and blood urea nitrogen by 22.3% and 25.86%, respectively. In addition, Cs-Cr supplementation increased muscle mass and muscle fiber density in exercise-trained mice and thus alleviated muscle damage caused by exercise. However, Cs-Cr powder exhibits poor stability during processing. Xanthan gum and locust bean gum (m/m = 6:4) has been demonstrated to increase the stability and viscosity of Cs-Cr beverages. Moreover, the addition of 1.5% CaSiO₃ also reduced the caking of the powder and increased the stability of the product. This study provides a theoretical basis for the application of Cs-Cr in a functional solid beverage. Full article

As probiotic microorganisms must remain viable at a certain level throughout the shelf life of fermented foods, various plant-based prebiotics are added to fermented dairy products. Pea (Pisum sativum L.) is a remarkable food source due to its prebiotic properties, high phenolic content and antioxidant capacity. In this study, fermented milks containing different proportions of pea fiber powder (0%, 0.5%, 1%, 1.5% and 2%) were produced using Limosilactobacillus reuteri ACC27, which has probiotic potential, and Streptococcus thermophilus 212S. The addition of pea fiber powder promoted the growth of Limosilactobacillus reuteri ACC27, increasing viable cell counts by approximately 1 log CFU/g compared to the control during storage. In addition, the fermentation time was shortened by approximately 30 min in samples containing pea fiber. Malic (84.07–175.58 mg/kg), lactic (11,670.45–13,791.66 mg/kg), acetic (145.12–240.53 mg/kg) and benzoic acids (17.07–20.34 mg/kg) were detected in all samples. Furthermore, pea fiber supplementation improved physicochemical properties by reducing syneresis and modifying water release behavior, while also increasing viscosity. The addition of pea fiber also enhanced total phenolic content and antioxidant capacity of the samples. The results of the principal component analysis revealed that the addition of pea fiber powder was associated with potentially improved functional attributes and enhanced probiotic viability under the studied conditions. Full article

Water-soluble pectin (WSP) is a soluble dietary fiber with a high esterification degree and certain viscosity and emulsifying properties. It has diverse bioactivities—including antioxidant, anticancer, and anti-inflammatory properties. This study aimed to investigate the in vitro antioxidant mechanisms of water-soluble pectin, and the in vivo effects of intestinal antioxidant capacity and gut microbiota composition in hybrid grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀). In an experiment involving feeding fish with WSP added to the diet, the addition of 600 mg/kg WSP promoted the activities of CAT, SOD, and GSH-Px in the grouper intestinal tract, thereby enhancing the antioxidant properties. At the phylum level, the relative abundance of Actinomycetes and Armatimonadetes decreased significantly. At the genus level, the relative abundance of Vibrio and Subdoligranulum increased significantly. In addition, antioxidant genes, inflammatory factor genes, immune genes, apoptosis genes, and genes of specific transmembrane proteins may participate in the regulation and improvement of the hybrid grouper intestinal tract. (CAT, MnSOD, and GPX), (TNF-α, IL-β, IL-6, and TGF-β), (MHC2, TLR3, KEAP1, and IKK-α), (C3, C8, C9, and P53), and (Claudin-3a, Occludin, ZO-1, and ZO-3) may regulate the intestinal function of hybrid grouper. Therefore, adding an appropriate volume of WSP to the diet is beneficial for the intestinal health of hybrid groupers. Full article

This study investigates the reutilization of polylactic acid (PLA) waste generated by 3D printing through its transformation into electrospun membranes with tunable morphological, surface, thermal, and filtration properties. Polymer solutions containing 5–10 wt % recycled PLA were prepared in a dichloromethane/dimethylformamide system and characterized in terms of viscosity and electrical conductivity. Increasing PLA concentration raised solution viscosity (41.87–339.83 mPa·s) and reduced conductivity (7.63–1.63 µS·cm⁻¹), promoting the formation of bead-free fibers with larger diameters (0.221–1.213 µm) and enhanced hydrophobicity (contact angles 112.34–124.38°). FTIR confirmed preservation of the polymer chemical structure after recycling and electrospinning, while DSC revealed reduced crystallinity in the fibrous membranes. Exploratory correlation analysis indicated consistent associations between solution properties, fiber morphology, and wettability. Increasing the number of electrospun layers (1–3) generated denser networks with reduced pore size and improved particle retention. Filtration tests conducted under controlled airflow conditions (85 L min⁻¹, 1 cm s⁻¹ frontal velocity, 50 cm² effective area) showed removal efficiencies above 90% for PM2.5 and PM5, while PM1 capture improved with increasing membrane thickness. Quality factor analysis highlighted the trade-off between filtration efficiency and pressure drop, identifying intermediate multilayer configurations as providing a favorable balance. These findings demonstrate that electrospinning offers an effective strategy for converting recycled PLA into structurally tunable membranes with adjustable filtration performance, supporting sustainable valorization of additive manufacturing waste. Full article

Delamination in laminated composites originates from premature matrix cracking within the interlaminar region, ultimately leading to ply separation under indirect loading. Among the techniques proposed to mitigate this failure mode, through-thickness stitching has emerged as a localized reinforcement strategy capable of enhancing interlaminar performance without modifying the in-plane laminate architecture. However, previous studies report that stitching can either improve or degrade the mechanical properties of the composite, with stitch density identified as a critical variable. This work aims to keep the tensile strength of a stitched composite at levels comparable to its unstitched counterpart. The reinforcement was applied using an eight-strand polyethylene thread (0.28 mm in diameter) embedded in a low-viscosity epoxy infusion system (MAX 1618 A/B) combined with a 90° biaxial fiberglass woven fabric. The tensile behavior of laminates was examined for three longitudinal stitching configurations consisting of 2, 3, and 5 continuous stitch lines. Results show that increasing stitch count produces a progressive reduction in tensile strength, attributed to stress concentration around stitch sites and microstructural effects such as resin-rich zones and fiber waviness. Full article

Polyethylene terephthalate (PET) plays a pivotal role in the chemical fiber industry, constituting over 50% of fiber consumption. However, the reduction of the recycled fiber-derived viscosity of the PET significantly impacts its spinning performance and restricts its closed-loop recycling to high-value regenerated fibers. To address these limitations, this study explored the viscosity improvement of black and white waste fiber-derived polyester particles through a two-step process involving micro-glycolysis and self-polycondensation. Initially, a continuous micro-glycolysis of fiber-derived PET was carried out in a twin-screw extruder with ethylene glycol (EG), which effectively cleaves the ester bonds in the PET chains, generating oligomers with reactive hydroxyl end groups. Subsequently, these oligomers were repolymerized without purification, and a higher molecular weight regenerated PET with enhanced intrinsic viscosity was obtained with antimony ethylene glycolate (Sb-EG) as a catalyst. The results revealed that the intrinsic viscosity decreased exponentially with increasing EG dosage during glycolysis, reaching approximately 50% of the initial value at 0.2–2 phr EG dosages. Optimal viscosity enhancement was achieved at a polycondensation time of 1–3 h, resulting in improved thermal stability and reduced crystallization temperatures. Importantly, regenerated PET samples with EG dosages of ≤2 phr demonstrated intrinsic viscosities of about 0.70 dL/g, meeting the standard for spin-grade polyester fiber, which is used to produce regenerated polyester fibers. This recycling process is low cost, environmentally friendly, and easy to scale-up, contributing significantly to the development of industrial recycling of waste polyester fabrics. Full article

(1) Background: Starch-based breads can closely mimic wheat bread in texture and appearance; however, their nutritional value must be improved while maintaining their inherent bread-like characteristics. The objective of this study was to incorporate whole-grain pearl millet flour (PMF) into a starch-based bread formulation to enhance its dietary fiber and protein content. (2) Methods: The PMF was obtained using a combination of laboratory rollers and hammer mills, as well as appropriate sieves to obtain a particle size ≤ 250 µm. The incorporation of PMF affected the properties of the base flour (BF), dough, and gluten-free bread (GFB). (3) Results: In the BF, setback viscosity was significantly reduced from 6379 to 1354 mPa·s. Similarly, in the freshly kneaded dough, both the elastic and viscous moduli decreased, from 168.3 to 17.8 kPa and from 36.3 to 4.3 kPa, respectively. During fermentation, dough-specific volume increased from 0.76 to 1.73 cm³/g. In the GFB, the moisture content decreased from 47.9 to 42.2%, bread specific volume varied from 2.13 to 2.68 cm³/g, and crumb hardness increased from 12.8 to 25.3 N. PMF incorporation segmented bread consumers into two preference-based clusters, characterized by lower (1) and higher (2) PMF levels. (4) Conclusions: Incorporating 30% PMF increased the fiber and protein contents of the starch-based bread by 4.9% and 2.2%, respectively, without compromising specific volume (2.56 g/cm³) or overall acceptance, which remained comparable to that of a commercial gluten-free bread (7.30 and 6.32 for clusters (1) and (2), respectively). Full article

Delamination is a major failure Mode in laminated composites, typically triggered by premature interlaminar matrix cracking and leading to severe structural degradation. To address this, various through-thickness reinforcement strategies have been explored, including three-dimensional woven architecture. Although these designs significantly improve delamination resistance, their industrial adoption stays limited due to reproducibility challenges and the high cost and operational complexity of advanced manufacturing systems needed for controlled through-thickness reinforcement. This study investigates an alternative interlaminar reinforcement method, through-thickness stitching, aimed at enhancing Mode-I delamination resistance of a commercial fiberglass laminate without changing its native architecture. Composites were manufactured using a low-viscosity epoxy infusion system (MAX 1618 A/B) and a [0/90] biaxial fiberglass fabric. An eight-filament polyethylene thread (Ø = 0.12 mm) was introduced in predefined stitch architectures consisting of three longitudinal patterns having two, three, and five continuous stitch lines, referred to as AV, BV and CV samples, respectively. Results show that stitching highly increases Mode-I interlaminar fracture toughness G_IC by 0.3808, 0.4152 and 0.5192 kJ/m² for AV, BV and CV respectively, compared to 0.0265 kJ/m² for the unstitched composite O, highlighting the strong influence of stitch orientation and spacing on interlaminar performance. But scanning electron microscopy revealed added failure mechanisms in stitched specimens, including localized fiber misalignment of up to 33° and resin-rich regions approximately 0.6 mm in length, suggesting that while stitching enhances delamination resistance, it may also influence other mechanical properties. Full article

This study investigates how natural fillers of different origins and morphologies influence the structural, thermal, rheological, and mechanical properties of thermoplastic elastomers (TPEs). Two series of materials were prepared: one based on a biobased matrix, poly(butylene 2,5-furandicarboxylate)-block-poly(tetramethylene oxide) (PBF-PTMO), and one based on a petroleum-derived matrix, poly(butylene terephthalate)-block-poly(tetramethylene oxide) (PBT-PTMO). Both series incorporated a range of natural modifiers, i.e., lignocellulosic fibers and ground fractions of Arundo donax L., cyanobacterial biomass (Spirulina platensis), and silica-rich mineral dust originating from volcanic stone quarries. The materials were obtained via melt blending, while the reference matrices (neat block copolymers) were synthesized through melt polycondensation. The chemical structure and limiting viscosity number (LVN) of the neat matrices were confirmed, while differential scanning calorimetry (DSC) provided insight into their morphology and phase composition. Scanning electron microscopy (SEM) was employed to evaluate the morphology and distribution of the modifiers within the polymer matrices. To assess how the fillers influenced processing windows and performance, thermogravimetric analysis (TGA), oscillatory rheological measurements, and tensile testing were performed. The results provide insight into structure–property relationships governing natural filler–TPE interactions and support the development of more sustainable elastomeric composites with tailored performance. Full article

Epoxy resins with excellent overall performance, are widely used in aerospace, automotive, and related fields, frequently in combination with reinforcing fibers to fabricate composites. To enable controllable epoxy processing for prepreg fabrication and composite forming, a rheological model and a curing kinetics model were developed and experimentally validated for an epoxy resin. Rotational rheometry was conducted to quantify the viscosity evolution with temperature and time, enabling construction of a corresponding rheological model. Comparison between model predictions and experimental measurements exhibited a high level of consistency across a wide temperature range. Furthermore, differential scanning calorimetry (DSC) was employed to measure heat-flow curves at different heating rates. The degree of curing was calculated from the heat-flow data, and an autocatalytic curing kinetics model was established based on a reaction kinetics formulation. And the accuracy of the model was verified by isothermal experiments. The developed rheological model provides a theoretical basis and practical guidance for resin processing and prepreg fabrication, whereas the curing kinetics model supports the design and control of curing and forming schedules for epoxy-matrix composites. Full article

Fine-denier silicone emulsions play an important role in the polyacrylonitrile (PAN) precursor treatment process by reducing surface tension and preventing fiber fusion during thermal stabilization and carbonization. These emulsions are typically prepared by dispersing polydimethylsiloxane (PDMS) polymers with various functional groups into water through different emulsification methods. In this study, two types of silicone emulsions—one prepared using a mechanical disperser and the other using a high-shear colloid mill—were manufactured on a pilot scale and systematically compared. Thermal aging was conducted at 50 °C and 70 °C for approximately one month, and changes in particle size, dispersion stability, and physicochemical properties were evaluated. The colloid-mill emulsification method produced smaller and more uniform silicone particles and exhibited superior thermal and dispersion stability relative to the mechanically dispersed emulsion. NMR relaxation, Turbiscan multiple light scattering, and viscosity measurements confirmed that the colloid-mill emulsion maintained a stable microstructure with minimal aggregation even under elevated-temperature storage. These results demonstrate that high-shear emulsification is an effective approach for producing fine-denier silicone emulsions with enhanced stability, making the colloid-mill method a more reliable and practical route for preparing silicone-based oiling agents used during PAN precursor processing in carbon fiber manufacturing. Full article

Biodegradable electrospun nanofibrous scaffolds (BENS) have emerged as a highly advanced class of wound dressings owing to their close structural and morphological resemblance to the native extracellular matrix and their tunable physicochemical and mechanical characteristics. However, the successful translation of electrospun wound-healing platforms from laboratory concepts to clinically viable products necessitates a quantitative understanding of how formulation and processing variables dictate scaffold architecture, mechanical performance, and antibacterial functionality. In this study, hydrophobic poly(ε-caprolactone) (PCL) and hydrophilic poly(ethylene glycol) (PEG35000) were blended at different weight ratios and fabricated into electrospun nanofibrous scaffolds, with amoxicillin trihydrate (AMX) incorporated as a model antibacterial agent. Blank and drug-loaded systems were systematically characterized with respect to solution rheology, fiber morphology, thermal behavior, crystallinity, mechanical performance, surface wettability, and antibacterial activity. Quantitative correlation analyses and statistical comparisons revealed that solution viscosity is a strong predictor of mechanical response, while PEG fraction governs baseline stiffness and crystallinity in a non-linear manner. AMX loading acted as a secondary structural modifier, producing statistically significant increases in stiffness and wettability, accompanied by reduced crystallinity and concentration-dependent antibacterial efficacy. Among the investigated formulations, a PCL: PEG ratio of 3:1 provided the most balanced mechanophysical profile for effective drug incorporation. These findings establish validated structure–property–function relationships that support the rational design of electrospun antibacterial wound dressings. Full article