Search Results (5,912)

Extrusion-based bioprinting faces significant challenges in achieving the shape fidelity and internal porosity necessary for cell viability, often hindered by subjective assessment methods. This study investigated the relationship between rheological properties and print quality using a natural polymer biomaterial ink composed of 12% gelatin, 5% alginate, and 1% carboxymethylcellulose. We conducted a comparative analysis between traditional pneumatic systems and screw-driven volumetric extrusion, utilizing a suite of quantitative metrics: Spreading Ratio (SR), Printability Index (P_r), Uniformity Ratio (UF), Collapse Angle (θ), and evaluated porosity. Our results demonstrate that the screw-driven system’s positive displacement mechanism provides superior control over filament morphology by enabling precise volumetric modulation. While the pneumatic system exhibited a high SR of 1.82 and the lowest porosity at 59.92%, the screw-driven system allowed for “under-extrusion” to compensate for viscoelastic die swell. Reducing the flow rate to 50% in the screw system lowered the SR to 1.09, nearly matching the nozzle diameter, and increased porosity to 76.46%. Furthermore, the screw-driven system achieved an ideal P_r of 1.0, whereas the pneumatic system produced distorted, rounded pores with a P_r of 1.57. The findings indicate that screw-driven extruders can decouple line complex rheology from the printing process, allowing for finer spatial resolution and better pore interconnectivity. Full article

Fibre properties significantly influence paper quality. This study investigates fibre property development along an industrial pulp production line, analysing morphological distributions and rheological behaviour to enhance refining performance indicators. Understanding these developments is critical for optimising resource efficiency and increasing industrial sustainability. Softwood thermomechanical pulp (TMP), from high-consistency (HC) and low-consistency (LC) refining, and bleached hardwood kraft pulp (BHKP) were examined. Fibre morphological properties were characterised using an optical fibre analyser, while suspension rheology was assessed using a pulp viscometer, supported by computational fluid dynamics (CFD) and discrete element method (DEM) simulations. Results demonstrate that fibre property distributions provide deeper insights into refining effects compared to average values alone. Systematic trends showed that HC-refined TMP from the first and second refining stage required significantly greater torque to break the fibrous network and fluidise the pulp compared to pulp that was also LC refined. This indicates that alterations in fibre properties, especially shortened fibre length resulting from different refining processes, govern fibre interactions in the three-dimensional network of the pulp suspensions and, therefore, their flow behaviour. In conclusion, combining morphological distribution analysis with specialised rheological measurements offers a robust tool for better understanding and monitoring mill-scale refining processes, enabling improved process optimisation in pulping and papermaking. Full article

Polycaprolactone (PCL) is widely utilized in bone tissue engineering due to its excellent biocompatibility and processability; however, its inherent bioinertness and hydrophobicity significantly restrict its clinical osteogenic efficacy. To overcome these limitations, we incorporated sol–gel synthesized silicate-based bioactive glass (BG) into a PCL matrix and fabricated a series of composite scaffolds with varying BG contents via direct ink writing (DIW) 3D printing. Rheological characterization confirmed that all ink formulations exhibited shear-thinning behavior, with viscosity increasing monotonically with BG content. DSC analysis revealed that BG incorporation progressively reduced the crystallinity of PCL from 51.47% to 36.23%. We systematically evaluated the physicochemical properties, mechanical resilience, and in vitro degradation behavior of these scaffolds. The results indicated that BG incorporation significantly improved the surface hydrophilicity, with the contact angle decreasing from 104.8 ± 2.81° to 69.8 ± 2.91°. Furthermore, as the BG content increased, the porosity and mechanical strength exhibited an initial increase followed by a subsequent decrease, yet all values remained within the range of human cancellous bone. Notably, cellular assays revealed that the introduction of 58SBG enhanced cell–matrix interactions; the PCL/BG scaffolds promoted superior cell attachment and more extensive morphological spreading compared to pure PCL. Among all groups, the PCL/30BG composite scaffold demonstrated the most optimal balance of mechanical integrity and biological response. Consequently, the PCL/30BG scaffold developed in this study exhibits immense potential as a bone graft substitute, providing a promising approach for clinical bone defect repair strategies. Full article

This review comprehensively examines the incorporation of nanoparticles (NPs) into biopolymers for 3D printing in biomedical applications, integrating material design, processing strategies, and translational considerations within a unified framework. Different types of NPs are analyzed regarding their effects on mechanical reinforcement, rheological modulation, and structural organization of biopolymeric matrices. The discussion covers principal additive manufacturing technologies, including extrusion-based systems such as fused deposition modeling (FDM) and direct ink writing (DIW), vat photopolymerization, powder-bed fusion (SLS), and emerging in situ nanoparticle formation approaches, emphasizing how nanoparticle loading and surface functionalization govern yield stress, shear-thinning behavior, viscoelastic recovery, and dimensional fidelity while mitigating agglomeration and optimizing interfacial interactions. Comparative evaluation of compressive modulus, strength, toughness, crystallinity, and porosity establishes structure–property–processing relationships directly linked to printability and functional performance. Biomedical applications are addressed in tissue engineering, biosensing, controlled and targeted drug delivery, and bioimaging, highlighting the balance between bioactivity and manufacturability. Finally, critical challenges—including compatibility, reproducibility, biological safety, long-term stability, regulatory adaptation, and environmental impact—are discussed, alongside future perspectives focused on green nanomaterials, AI-driven predictive formulation design, and digital twins for real-time monitoring and quality control in nano-enabled additive manufacturing. Full article

Cement-based grouts used in anchorage engineering often suffer from insufficient flowability, bleeding, and inadequate early-age strength, which may impair grout filling quality and interfacial bonding. This study investigated the synergistic use of fly ash (FA) and metakaolin (MK) to optimize the fresh properties, strength development, microstructure, and early-age anchorage performance of cement-based grouts. Rheological behavior, bleeding rate, and compressive strength were evaluated for grouts with different FA and MK contents, and the overall performance was ranked using the entropy-weighted TOPSIS method. X-ray diffraction and scanning electron microscopy were further employed to clarify the underlying microstructural evolution, and laboratory pull-out tests were conducted to verify the early-age anchorage effectiveness of the selected optimal mixtures. The results showed that the optimal performance was achieved at 15–20% FA and 3–6% MK. Within this range, grout viscosity decreased from 0.24 to 0.16 Pa·s, bleeding rate decreased from 13% to 2%, and compressive strength increased markedly at both 7 and 28 days. The optimized grout also increased the peak interfacial shear stress from 0.440 to 0.978 MPa. These improvements were associated with accelerated hydration, reduced CH and residual clinker phases, and a denser hydration-product network. The pull-out specimens failed predominantly along the grout–rock/soil interface, and the improved anchorage response was attributed to a denser hydration-product network that reduced pores and interfacial defects and promoted more efficient shear-stress transfer. Full article

Eucommia ulmoides gum (EUG), a sustainable plant-derived natural polymer, was functionalized via three distinct routes, including vulcanization, epoxidation, and hydroxylation to yield vulcanized (VEUG), epoxidized (EEUG), and hydroxylated EUG (HEUG), respectively. We systematically characterized the effects of modification route and degree on the chemical structure, crystallization behavior, thermal stability, hydrophilicity, and mechanical properties of functionalized EUG and further evaluated the high/low-temperature performance, microstructure, and mechanical properties of the corresponding modified asphalt binders (VEMA, EEMA, HEMA) as a function of modifier type and loading. For VEUG, C-S cross-linking networks formed during vulcanization suppress EUG crystallization, enabling a rigid-plastic to elastic transition, while high-temperature cleavage of C-S bonds reduces its initial thermal stability. For EEUG, epoxidation breaks C=C double bonds and introduces epoxy groups to strengthen intermolecular interactions; subsequent ring-opening grafting of hydroxyl groups onto EEUG yields HEUG, which forms additional cross-links via dynamic hydrogen bonds. Increasing modification degree for both EEUG and HEUG reduces their number- and weight-average molecular weights with narrower distribution, diminishes crystallinity, enhances thermal stability and hydrophilicity, and drives a rigid-plastic to elastic transition, characterized by decreased strength (0.65 MPa < σ_HEUG < σ_EEUG < 10.18 MPa) and markedly improved ductility (143.6% < ε_EEUG < 262.0%, 679.9% < ε_HEUG < 1360.3%). In asphalt binders, VEUG’s cross-linked network endows VEMA with refined more abundant bee-like microstructures, drastically boosting high- and low-temperature performance: relative to pristine EUG-modified asphalt (EUGMA), VEMA’s DMT modulus decreases by 94%, and adhesion increases by 87%. EEMA forms covalent bonds with polar asphalt components via epoxy groups, while HEMA constructs a hydrogen-bonded cross-linked network; both effectively inhibit asphaltene aggregation. With increasing modifier loading, EEMA and HEMA exhibit increased modulus, reduced adhesion, and gradually improved high- and low-temperature performance, except for the non-significant high-temperature enhancement of HEMA at higher loadings. Full article

The development of alternative fat systems for confectionery glazes requires precise control of melting behavior, solid fat content, and rheological performance. In this study, binary fat systems based on fully hydrogenated rapeseed oil (FHRSO) and refined sea buckthorn oil (RSBO) were developed and modified by chemical interesterification for application in non-tempered confectionery glazes. Interesterified blends with FHRSO/RSBO ratios of 10/90, 20/80, and 30/70 were characterized in terms of fatty acid composition, trans fatty acid isomers, melting behavior, solid fat content (SFC), and rheological properties. The investigated systems were distinguished by a high content of palmitoleic acid (C16:1) derived from RSBO, while increasing FHRSO content led to higher saturated fatty acid levels, higher melting temperatures, and increased SFC values. Among the tested formulations, the FHRSO/RSBO 20/80 blend exhibited the most balanced functional profile, showing moderate melting characteristics, an SFC value of approximately 15% at 30 °C, and favorable Casson viscosity for glaze processing. A confectionery glaze prepared with this fat system showed good flow behavior during application, rapid setting at ambient temperature, and stable surface appearance during 30 days of storage. The results demonstrate that chemically interesterified FHRSO/RSBO systems, particularly the 20/80 formulation, represent a promising alternative lipid base for non-tempered confectionery glazes. Full article

Corneal defects are a major cause of vision loss and require rapid, biocompatible, and effective sealing methods to restore ocular integrity and prevent infection. Current clinical adhesives, such as cyanoacrylate and fibrin glue, are limited by problems such as poor biocompatibility and inadequate stability. This study presents the design and evaluation of a fast-curable polymer bioadhesive hydrogel, a corneal glue formulated for efficient sealing of corneal defects. Hydrogels were synthesized from natural and synthetic polymers, including polyvinyl alcohol (PVA), sodium alginate (SA), and carboxymethyl cellulose (CMC), optimized for rapid gelation (~45 s), robust adhesion (~15 kPa), and mechanical strength (tensile strength ~0.35 MPa and storage modulus G′ indicating strong elastic behavior). Physicochemical and rheological properties, including swelling behavior and optical transparency (>90% transmittance across 400–700 nm), were characterized, including gelation time, swelling behavior, and mechanical strength. In vitro biocompatibility was assessed using human corneal epithelial cells to evaluate cytotoxicity and cell adhesion. Ex vivo studies on human cadaveric corneas with full-thickness defects measured adhesive strength and sealing efficacy through burst pressure (~38 mmHg) and leakage tests, with comparisons to commercial fibrin and cyanoacrylate adhesives. The optimized corneal glue exhibited fast curing, robust adhesion, high water retention with minimal swelling, favorable viscoelastic properties, and excellent cytocompatibility effectively sealing corneal defects in ex vivo models. These results highlight its potential as a promising fast-curable bioadhesive for corneal wound repair and ocular surface restoration. Full article

The Zircaloy-4 alloy is a key structural material for nuclear reactor cores. However, its behavior under warm deformation conditions and during phase transformations requires in-depth investigation to improve technologies for producing ultrafine-grained (UFG) structures using severe plastic deformation methods. This work presents a comprehensive study of the rheological properties, phase stability, and microstructural evolution of the alloy in the temperature range from 20 to 950 °C at strain rates of 0.5 and 15 s⁻¹. The experimental part included plastometric testing, dilatometric analysis, and microstructural characterization. It was established that the optimal window for plastic deformation corresponds to warm deformation at 650 °C. Dilatometric analysis confirmed that heating to 650 °C ensures the preservation of a stable initial α-phase structure, since the formation of secondary phases and the α→β transformation are initiated at higher temperatures, namely 694 °C (onset) and 847 °C (completion). At 650 °C, the deformation resistance decreases by approximately 70% compared to cold processing, while the strain-rate sensitivity of the flow stress is minimized. EBSD analysis showed that deformation under these conditions leads to intensive grain fragmentation via mechanisms of dynamic recovery and the initial stages of continuous dynamic recrystallization. The decisive role of the kinetic factor was demonstrated: reducing the strain rate to 0.5 s⁻¹ promotes the formation of a finer and more homogeneous grain structure. In contrast, high strain-rate deformation (15 s⁻¹) results in coarser grains and increased non-relaxed intragranular residual stresses. The obtained results provide a physical basis for optimizing thermomechanical processing regimes and can be used to produce UFG structures in zirconium alloys without the risk of phase degradation. Full article

The aim of this study was to evaluate the effects of oil type, fat level, storage time, and storage temperature on the microbiological, physicochemical, sensory, microstructural, and oxidative stability properties of vegan mayonnaise. For this purpose, a 70% oil formulation was used as the full-fat reference system, whereas a 50% oil formulation was evaluated as a lower-fat experimental system. These formulations were prepared using palm, soybean, cottonseed, and canola oils and stored at 25 °C for 120 days, 37 °C for 60 days, and 55 °C for 30 days. The quality attributes of the samples were systematically monitored under these storage conditions. The results showed that canola- and soybean oil-based formulations exhibited superior emulsion stability and sensory acceptability in both systems. In contrast, palm oil-based samples, particularly the 50% oil formulations, showed pronounced phase separation and markedly lower emulsion stability, indicating limited structural compatibility under lower-fat conditions. Overall, the findings demonstrated that oil type and fat level strongly influenced the quality characteristics of vegan mayonnaise, while storage time and temperature were important in determining the evolution and preservation of these properties under the tested conditions. These results provide useful guidance for the development of stable and acceptable plant-based mayonnaise products. Full article

Driven by global carbon reduction targets, supersulfated cement has emerged as a promising low-carbon cementitious material. This study investigates the influence of a polycarboxylate superplasticizer (PCE) on the rheological behavior and early interfacial evolution of phosphogypsum-based supersulfated cement (PSSC). Rheological measurements, pore solution ion analysis, hydration heat analysis, X-ray diffraction (XRD), and scanning electron microscopy coupled with energy-dispersive spectroscopy (SEM–EDS) are employed to correlate early hydration processes with structural development. The results indicate that the incorporation of PCE significantly reduces the initial yield stress and moderates the structural build-up rate. At a PCE dosage of 0.3 wt.%, the initial static yield stress decreases from 1313 Pa to approximately 125 Pa, while the structural build-up index I_s,s reaches 10.19, indicating improved particle dispersion while maintaining progressive structural reconstruction during hydration. Phosphogypsum (PG) functions not only as a sulfate source but also as an active interfacial substrate that promotes the preferential nucleation of AFt on its surface. In the absence of PCE, continuous Ca–P-enriched layers form on PG particles, accompanied by localized AFt accumulation. After the incorporation of PCE, the primary crystalline phases remain unchanged; however, gypsum dissolution and AFt formation are delayed. Meanwhile, Ca–P enrichment shifts from continuous coverage to a more dispersed distribution, promoting the spatially separated growth of AFt crystals rather than dense localized aggregation. Overall, PCE influences the evolution of the structure and properties of the system by regulating early interfacial reactions and the spatial organization of hydration products. Full article

Warm-mix asphalt (WMA) technology and basalt fiber modification have been increasingly applied in road engineering. However, conventional basalt fibers often disperse unevenly and tend to agglomerate. In this study, basalt fiber powder (BFP) was incorporated into a Sasobit-based WMA system and systematically compared with matrix asphalt, Sasobit-modified WMA, conventional basalt fiber-modified WMA, and styrene butadiene styrene (SBS)-modified asphalt. Multiscale characterization—including dynamic shear rheometry (DSR), bending beam rheometry (BBR), scanning electron microscopy (SEM), and nanoindentation—was conducted to elucidate rheological behavior and interfacial micromechanical responses. The corresponding Asphalt Concrete-13 (AC-13) mixtures were further evaluated through rutting tests, low-temperature bending tests, and moisture susceptibility tests. Results demonstrate that micronized BFP achieves more homogeneous dispersion within the asphalt matrix and may promote a more effective reinforcing morphology, significantly enhancing high-temperature deformation resistance while partially mitigating the low-temperature stiffness increase induced by Sasobit. Compared with conventional basalt fiber systems, BFP shows better stress relaxation capacity and interfacial mechanical response under the tested conditions. At the mixture level, the BFP–Sasobit system showed the best overall performance, with the dynamic stability increasing by 242.2% relative to the base asphalt mixture and the residual Marshall stability reaching 92.3%, while the low-temperature flexural strain increased by 33.3%. Overall, the findings suggest that morphology-controlled micronization provides a morphology-guided enhancement strategy for Sasobit-based warm-mix asphalt by promoting coordinated improvements across the rheological, micromechanical, and mixture scales. Full article

To address high-temperature stability demands and promote resource utilization, this study investigates coal–oil co-processing residue (COCR) as an asphalt modifier. Penetration, softening point, ductility, rheological, and aging/storage evaluations were conducted on asphalt with varying COCR contents. Modification mechanisms were analyzed using FTIR, GPC, and SARA fractionation. The results revealed that COCR significantly enhanced high-temperature performance while slightly reducing low-temperature performance, showing good storage stability. At a 10% COCR content, the rutting factors of 70# and 90# asphalt increased by 44.8% and 46.2%, respectively, at 52 °C. Increased asphaltene content indicated that COCR reinforced the colloidal structure, thus improving the deformation resistance. At a 15% COCR content in mixture, the dynamic stability of asphalt mixtures increased by approximately 53.5% and 59.7% for 70# and 90# base asphalt, respectively. Considering overall performance balance, 10% COCR in 90# base asphalt would be recommended for regions with hot summers and warm winters. Full article

Excessive sodium intake is a major dietary concern, leading to recommended reductions in several food categories, including cheese. This study aimed to evaluate how cheese composition and texture influence sodium release and perceived saltiness during consumption. Semi-hard cheeses (SHCs) with varying compositions were analyzed for chemical composition, rheological properties, and sensory attributes using quantitative descriptive analysis, temporal sodium release and saltiness intensity. Most compositional factors affected the sensory characteristics of SHCs and the dynamic perception of saltiness. In particular, salt level influenced not only the perceived intensity of saltiness but also bitterness, acidity, overall aromatic intensity, and numerous textural characteristics. The fat content also influenced texture perception and masked taste attributes. Moreover, both sodium release and saltiness perception decreased with increasing fat content. These findings highlight the importance of compositional and textural factors in modulating salt perception and provide useful insights for developing reduced-salt cheeses with acceptable sensory qualities. Full article

A sustainable polymer-based filtration control system was developed for high-temperature, high-density water-based drilling fluids. The system’s rheological stability, filtration performance, and filter cake properties were evaluated under varying conditions of temperature, salinity, and density. The drilling fluid density ranged from 1.80 to 2.20 g/cm³, the temperature from 25 to 150 °C, and the NaCl mass fraction w(NaCl) = 5–20%. The results indicated that increasing fluid density resulted in a progressive increase in apparent and plastic viscosities (from 42.6/28.4 mPa·s to 65.1/47.9 mPa·s), while the yield point remained relatively stable (14.2–17.2 Pa), suggesting that high solid loading enhanced viscous dissipation without inducing structural stiffening. Filtration loss increased moderately with temperature (6.8–12.3 mL at 25–150 °C) and salinity (6.8–10.7 mL at w(NaCl) = 5–20%), whereas it decreased significantly with increasing density (13.1–9.4 mL at 1.80–2.20 g/cm³), indicating a density-dominated filtration regime. At 120 °C, w(NaCl) = 12%, and 2.00 g/cm³, the developed system achieved a low filtration loss of 8.4 mL, outperforming three representative conventional filtration-control systems, including starch-based, sulfonated asphalt-based, and polymer-based technologies. Filter cake analysis revealed that increasing density facilitated the packing of multi-scale solids, reducing filter cake thickness from 1.62 mm to 0.98 mm and permeability from 1.34 × 10⁻¹⁵–4.05 × 10⁻¹⁶ m², while significantly improving resistance to erosion and compression. These findings demonstrate that the combination of interfacial stabilization and filter cake densification offers a robust and controllable filtration solution for high-temperature, high-density drilling environments, presenting a promising approach for drilling fluid systems in challenging conditions. Full article