Search Results (1,015)

Unconventional low-permeability reservoirs present significant production challenges due to the poor imbibition and displacement efficiency of conventional polymer fracturing fluids. The injection of nanoparticle (NP) compounds into polymer fracturing fluid base systems, such as linear gels or slickwater, has garnered significant research interest due to their superior performance. However, previous studies have primarily focused on evaluating the fluid’s properties, while its imbibition and oil displacement mechanisms within reservoirs remain unclear. Herein, the imbibition mechanism of nanoparticle composite polymer fracturing fluid was systematically investigated from macro and micro perspectives using low-field nuclear magnetic resonance (LF-NMR), atomic force microscopy (AFM), interfacial rheology, and other technical means. The results showed that the imbibition recovery using polymer fracturing fluid was 10.91% higher than that achieved with conventional slickwater. Small and medium pores were identified as the primary contributors to oil drainage. Nanoparticles can be adsorbed on the rock wall in the deep reservoir to realize wettability reversal from oil-wet to water-wet, reducing crude oil adhesion. Furthermore, a strong interaction between the adsorbed NPs and cleanup agents at the oil–water interface was observed, which reduces interfacial tension to 0.95 mN·m⁻¹, mitigates the Jamin effect, and enhances interfacial film deformability. NPs increase the interfacial dilatational modulus from 6.0 to 14.4 mN·m⁻¹, accelerating fluid exchange and oil stripping. This work provides a consolidated mechanistic framework linking NP-induced interfacial modifications to enhanced pore-scale drainage, offering a scientific basis for designing next-generation fracturing fluids. We conclude that NP-compound systems hold strong potential for low-permeability reservoir development, and future efforts must focus on optimizing NP parameters for specific reservoir conditions and overcoming scalability challenges for field deployment. Full article

Wellbore instability in shale formations represents a worldwide challenge in drilling engineering. The development of high-performance shale stabilizers is crucial for enhancing wellbore stability. A core–shell structured shale stabilizer, designated AAD-CaCO₃, was synthesized via inverse emulsion polymerization using acrylamide (AM), 2-acrylamido-2-methylpropanesulfonic acid (AMPS), and dimethyl diallyl ammonium chloride (DMDAAC) as monomers. Nano-CaCO₃ was generated in situ by reacting calcium chloride and sodium carbonate. Sodium bisulfite and ammonium persulfate were used as initiators. The product was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and thermogravimetric analysis (TGA). Its effects on the rheological properties and filtration performance of a bentonite-based mud were evaluated. The stabilizer’s efficacy in inhibiting shale hydration swelling and dispersion was evaluated through linear swelling tests and shale rolling dispersion experiments, while its plugging performance was examined via a filtration loss test with a nanoporous membrane and spontaneous imbibition tests. The results indicated that AAD-CaCO₃ possesses a core–shell structure with the nano-CaCO₃ encapsulated by the polymer. It moderately improved the rheology of the bentonite-based mud and significantly reduced both the low-temperature and low-pressure (LTLP) filtration loss and the high-temperature and high-pressure (HTHP) filtration loss. AAD-CaCO₃ could be adsorbed onto shale surfaces through electrostatic attraction, resulting in substantially reduced clay hydration swelling and an increased shale cutting recovery rate. Effective plugging of micro-nanopores in shale was achieved, demonstrating a dual mechanism of chemical inhibition and physical plugging. Full article

Cemented paste backfill (CPB) is widely used in mining operations to enhance underground stope stability, production, and safety. Accurately predicting paste flow behaviours in backfill reticulation circuits is crucial for efficient delivery control and asset longevity. However, the predictions remain challenging due to complex rheology and flow-induced particle heterogeneities of CPB. This study develops a computational fluid dynamics (CFD)-based analysis framework to investigate flow dynamics of the CPB and the wear conditions of the pipes, considering slip layer and shear-induced particle migration. Experimental loop tests are conducted to measure pressure drops of CPB at different velocities, providing data for validating the developed CFD model. Simulation results are in good agreement with the measured pressure drops and wear rates of the internal pipeline wall. Furthermore, comparisons with existing models indicate that the developed model provides more accurate predictions. Microscopical analyses reveal that shear-induced particle migration leads to the formation of a distinct plug flow region, with particles accumulating near the unyielded boundary. Meanwhile, a low particle concentration near the pipe wall reduces local viscosity and pressure drop. Parametric studies reveal that increased flow velocity and reduced pipe diameter significantly elevate both pressure drop and wear rate, while higher solid concentrations induce nonlinear rheological effects. Full article

Polylactic acid (PLA) is a promising biodegradable polymer whose widespread application is hindered by inherent brittleness. Polyethylene glycol (PEG) is a common plasticizer, but the effects of intermediate molecular weights, such as 4000 g/mol, on the coupled thermal, mechanical, and rheological properties of PLA remain insufficiently understood. This study presents a comprehensive analysis of PLA plasticized with 0–20 wt% PEG 4000, employing differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and rheology. DSC confirmed excellent miscibility and a significant glass transition temperature (T_g) depression exceeding 19 °C for the highest concentration. A complex, non-monotonic evolution of crystallinity was observed, associated with the formation of different crystalline forms (α′ and α). Critically, DMA revealed that the material’s thermo-mechanical response is dominated by its thermal history: while the plasticizing effect is masked in highly crystalline, as-cast films, it is unequivocally demonstrated in quenched amorphous samples. The core finding emerges from a targeted rheological investigation. An anomalous increase in melt viscosity and elasticity at intermediate PEG concentrations (5–15 wt%), observed at 180 °C, was systematically shown to vanish at 190 °C and in amorphous samples. This proves that the anomaly stems from residual crystalline domains (α′ precursors) persisting near the melting point, not from a transient molecular network. These results establish that PEG 4000 is a highly effective PLA plasticizer whose impact is profoundly mediated by processing-induced crystallinity. This work provides essential guidelines for tailoring PLA properties by controlling thermal history to optimize flexibility and processability for advanced applications, specifically in melt-processing for flexible packaging. Full article

Rosacea is a chronic inflammatory skin disorder characterized by oxidative stress, innate immune dysregulation, vascular instability, and microbiome-related triggers. Glycyrrhiza glabra (Gg, licorice) root contains phenolics and triterpenoids with antioxidant, anti-inflammatory, antimicrobial, and anti-angiogenic properties that may benefit rosacea-prone skin. Xanthan-gum hydrogels containing 2% methanolic Gg extract (S1, S2) were prepared and characterized. Rheology, in vitro release, and in vitro permeation were evaluated, with the aim of assessing their suitability as topical formulations for rosacea-prone skin. Antioxidant activity was assessed using DPPH, ABTS, and FRAP assays. Antimicrobial effects were tested against S. pyogenes, S. aureus, and C. acnes. Safety and bioactivity were examined through HaCaT keratinocyte assays (MTT, Neutral Red, LDH), the HET-CAM irritation test, and the CAM angiogenesis assay. Immunocytochemistry was performed on rosacea-related inflammatory markers. Both hydrogels showed suitable rheology, sustained release, and preserved strong antioxidant activity. Moderate antimicrobial effects were observed, particularly against S. pyogenes and C. acnes. HaCaT cell viability remained above 84% for the S2 formulation at the highest concentration (200 µg/mL), indicating improved cytocompatibility compared with formulation S1. The hydrogels were non-irritant in the HET-CAM model and reduced neovascularization in the CAM assay, with a more sustained effect observed for formulation S2. Immunohistochemistry supported potential modulation of inflammatory pathways relevant to rosacea, evidencing suppressed VEGF expression and preserved CD44-mediated integrity, particularly in the Labrasol-based formulation (S2), while Caspase-3 staining indicated a controlled apoptotic profile. Overall, Gg hydrogels are safe, biocompatible, non-irritant, and exhibit antioxidant, antimicrobial, and anti-angiogenic activities, supporting their potential as biocompatible topical formulations with antioxidant and pathway-modulating properties relevant to the biological features associated with rosacea, while underscoring the importance of formulation design. Full article

Coronary artery disease (CAD) remains the leading cause of cardiovascular mortality worldwide. Accurate and non-invasive quantification of coronary hemodynamics, namely in the right coronary artery (RCA), is essential for clinical decision-making but remains challenging due to the complex interaction among vessel geometry, pulsatile flow, and blood rheology. This study presents and validates a transparent computational framework for non-invasive fractional flow reserve (FFR) estimation using patient-specific RCA geometries reconstructed from coronary computed tomography angiography (CCTA) using SimVascular 27-03-2023. The proposed workflow integrates realistic boundary conditions through a Womersley velocity profile and a three-element Windkessel outlet model, coupled with a viscoelastic blood rheology formulation (sPTT) implemented via user-defined functions (UDFs). This work integrates all clinically relevant conditions of invasive FFR assessment into a single patient-specific computational framework, while delivering results within a time frame compatible with clinical practice, representing a meaningful methodological advance. The methodology was applied to seven patient-specific cases, and the resulting non-invasive FFR values were compared with both invasive wire-based measurements and commercial HeartFlow^® outputs (Mountain View, CA, USA). Under hyperemic conditions, the computed FFR values showed strong agreement with invasive references, with a mean relative error of 8.4% ± 6.3%, showing diagnostic consistency similar to that of HeartFlow^® (8.3% ± 8.1%) for the selected dataset. These findings demonstrate the ability of the proposed CFD-based pipeline to accurately replicate physiological coronary behavior under hyperemia. This novel workflow provides a fully on-site, open-source, reproducible, and cost-effective framework. Ultimately, this study advances the clinical applicability of non-invasive CFD tools for the functional assessment of CAD, particularly in the RCA. Full article

The increasing demand for food is the driving force behind the search for novel, more selective, and less hazardous agrochemicals. Natural products are gaining prominence recently due to the promise of being green agrochemicals, but many natural products are poorly soluble in water, which reduces their applicability. In this work, we successfully formulated a water-insoluble Saussurea lappa root extract into a stable aqueous suspension using xanthan gum. The colloidal suspension was characterized by rheology, dynamic light scattering, and zeta potential. The results demonstrated that the suspension is a stable, sprayable, shear-thinning viscoelastic system (weak gel). A series of S. lappa solutions with xanthan gum were prepared and tested against five plant species, observing the inhibitory effect on the shoots and roots. The results were also compared with the commercial herbicide Dual. The S. lappa extract presented results comparable to or even greater than Dual for Lactuca sativa, Cucumis sativus, Brachiaria decumbens, and Bidens pilosa. However, it showed low inhibitory activity for Sorghum bicolor, highlighting its potential for selective weed control. This work illustrates xanthan gum as an effective vehicle for formulating insoluble natural products and demonstrates that S. lappa extract is a promising candidate for developing novel herbicides. Full article

This study systematically examines the fluidity, setting time, mechanical properties, and microstructural evolution of metakaolin-based geopolymer grouting materials with a relatively high water-to-solid (W/S) ratio window. A four-factor, three-level orthogonal experimental design was employed to identify the dominant factors and main effect trends of W/S ratio, alkali dosage, water glass modulus (Ms, molar ratio of SiO₂ to Na₂O in alkali solution), and steel slag content on the material’s performance. The results indicated that the W/S ratio predominantly governed fluidity, while the alkali content was the primary controlling factor for setting time and early-age strength. An intermediate range of water glass modulus with a value of 1.6 provided balanced performance. The incorporation of steel slag with a range of 10–20% showed an age-dependent contribution: it not only tended to improve the rheology of the paste but also the later-age strength. XRD, FTIR, and SEM/EDS results suggested that the hardened binders were dominated by amorphous products, where alumimosilicate gel (N-A-S-H) and Ca-containing gel (C-S-H/C-A-S-H) may coexist depending on calcium availability and activator chemistry. The proposed parameter ranges are valid within the studied design space and provide guidance for the mix design of high-W/S geopolymer grout. Full article

Circulation is one of the most prevalent and severe complications during the drilling and completion of deep and ultra-deep wells, especially in fractured and karstic formations. In regions such as the Sichuan Basin, bottom-hole temperatures exceeding 200 °C, limited formation strength, and frequent lithological alternations significantly reduce the effectiveness of conventional granular materials under high-temperature and long open-hole conditions. Bridging-type plugging systems based on particle gradation or principles often exhibit low success rates due to fiber softening, rubber aging, and erosion-induced deterioration of the sealing structure. In this study, a high-temperature-resistant bridging composite system was developed to meet the extreme conditions in deep and ultra-deep wells. By incorporating temperature-resistant bridging particles and flexible reinforcing components, the slurry establishes a synergistic “bridging–filling–densification” sealing mechanism. Meanwhile, the combined use of retarders, fluid-loss reducers, and rheology modifiers ensures stable pumpability and adequate curing densification at 200 °C. Overall, the results provide new insights and experimental evidence for the design of high-temperature cement-based plugging materials, offering a promising approach for improving loss-control effectiveness and wellbore strengthening in complex intervals. Full article

With the increasing requirements for “Green Mine” construction, Cemented Tailings Backfill (CTB) has emerged as the preferred strategy for solid waste management and ground pressure control in underground metal mines. However, full tailings, characterized by wide particle size distribution and high fine-grained content, exhibit complex physicochemical properties that lead to significant non-linear behavior in slurry rheology and strength evolution, posing challenges for accurate prediction using traditional empirical formulas. Addressing the issues of significant strength fluctuations and difficulties in mix proportion optimization in a specific lead–zinc mine, this study systematically conducted physicochemical characterizations, slurry sedimentation and transport performance evaluations, and mechanical strength tests. Through multi-factor coupling experiments, the synergistic effects of cement type, cement-to-tailings (c/t) ratio, slurry concentration, and curing age on backfill performance were elucidated. Quantitative results indicate that solids mass concentration is the critical factor determining transportability. Concentrations exceeding 68% effectively mitigate segregation and stratification during the filling process while maintaining optimal fluidity. Regarding mechanical properties, the c/t ratio and concentration show a significant positive correlation with Uniaxial Compressive Strength (UCS). For instance, with a 74% concentration and 1:4 c/t ratio, the 3-day strength increased by 1.4 times compared to the 68% concentration, with this increment expanding to 2.0 times by 28 days. Furthermore, a comparative analysis of four cement types revealed that 42.5# cement offers superior techno-economic indicators in terms of reducing binder consumption and enhancing early-age strength. This research not only establishes an optimized mix proportion scheme tailored to the operational requirements of the lead–zinc mine but also provides a quantitative scientific basis and theoretical framework for the material design and safe production of CTB systems incorporating high fine-grained full tailings. Full article

Puerarin is a naturally occurring isoflavone with reported anticancer activity, yet its topical translation is constrained by limited stability and suboptimal dermal delivery. A Puerarin-loaded proniosomal gel was developed as a potential dermal delivery platform, and we performed an initial assessment of its antimelanoma activity and safety. The gel was produced by coacervation–phase separation using Span 60, Tween 80, phosphatidylcholine, and cholesterol. Physicochemical characterization included pH, entrapment efficiency, rheology, FTIR, DSC, and vesicle properties (DLS, PDI, ζ-potential). In silico geometry optimization and docking were carried out for melanoma-associated targets (MITF and DNMT3B). Biological effects were investigated in vitro on A375 melanoma cells using MTT, morphological analysis, and nuclear/mitochondrial staining, while irritation potential was evaluated in ovo by HET-CAM. The optimized formulation exhibited a skin-compatible pH and an entrapment efficiency of 62 ± 0.26%. DLS indicated a multimodal population, with a major number-weighted vesicle population in the 100–200 nm range, and a ζ-potential of −34.9 ± 0.14 mV. FTIR and DSC supported component incorporation without evidence of chemical incompatibility. The gel showed non-Newtonian, pseudoplastic, thixotropic flow, which is advantageous for topical use. Docking predicted meaningful affinities of Puerarin toward MITF and DNMT3B. The formulation reduced A375 viability in a dose-dependent manner (to 44.66% at 200 µg/mL) and, at higher concentrations, produced nuclear condensation and disruption of the mitochondrial network. HET-CAM classified the gel as non-irritant. The Puerarin-loaded proniosomal gel represents a promising topical platform with preliminary in vitro antimelanoma cytotoxic potential, warranting additional studies to validate skin delivery, efficacy, and safety. Full article

This study reports the effect of pH (2, 7, 10) and heat treatment (80 °C for 30 min) on the oil–water (o/w) interfacial behavior of hemp seed protein isolate (HPI) aqueous dispersions. The physicochemical, interfacial adsorption, rheology, and emulsifying properties of protein dispersions were evaluated. HPI dispersions at pH 10 exhibited the highest water solubility (60%), the greatest net charge (−27 mV), and the lowest hydrophobicity (~5 a.u.), promoting o/w interfacial pressure (π) and interfacial viscoelasticity. Strong interfacial viscoelastic protein layers (E^* = 25 mN/m) were also observed under acidic conditions (pH 2), where proteins exhibited high solubility (40%), a high positive net charge (21 mV), and increased hydrophobicity (46 a.u.). HPI dispersions in their neutral state (pH 7) were not able to form stable o/w emulsions due to their poor physicochemical properties such as low solubility (18%), low surface charge (−18 mV), and hydrophobicity (~5 a.u.). Heat treatment significantly increased the charge and hydrophobicity of both neutral and alkaline proteins (~30 mV and ~10 a.u., respectively), increasing their particle size distribution and ultimately reducing their interfacial protein layer elasticity (E^* = 20 and 13 nM/m, respectively). While particles at acidic conditions showed high thermal resistance, heat treatment improved the emulsifying stability in alkaline conditions while further reducing it in the neutral state. Overall, HPI dispersions demonstrated the ability to form stable emulsions at both alkaline and acid pHs, with those formed at pH 2 exhibiting a lower droplet size and superior stability. Full article

Potato starch offers the unique potential of mineral enrichment through the presence of phosphorylated amylopectin chains. This property was utilised in a straightforward dual modification of native potato starch by combining mineral enrichment with dry heat treatments (DHT). DHT itself (110–130 °C, 3–6% moisture, 2 h) affords potato starches with lower viscosity and gelatinisation temperatures and higher contents of digestible starch. Prior ion exchange with Na⁺, K⁺, Mg²⁺, and Ca²⁺ enhanced the versatility of dry heat treatments. This study demonstrates the fine-tuning of functional properties (rheology) of these novel, dual-modified starches. Of special interest are magnesium and calcium due to their nutritional value and their valency, allowing ionic cross-linking. The present study contributes to the understanding of starch–ion interactions in DHT, clearly highlighting the role of specific ion effects, as per the Hofmeister series (K⁺ > Na⁺ and Ca²⁺ > Mg²⁺), in addition to the reversible ionic cross-linking effect of divalent cations. This knowledge is of use for potential substitution of chemically modified starches in food products, serving relevant trends and needs of today’s food industry for clean-label starches. Full article

Conjugate heat transfer in non-Newtonian fluids is a fundamental phenomenon in thermal management systems. This study investigates the combined effects of magnetic field topology, heat absorption/generation, the thermal conductivity ratio, enclosure inclination, and power-law rheology using the lattice Boltzmann method. The parametric analysis shows that increasing the heat generation coefficient from −5 to +5 reduces the average Nusselt number by up to 97% for the pseudo-plastic fluids and up to 29% for the Newtonian fluids, while entropy generation increases by 44–86% depending on the thermal conductivity ratio. Increasing the inclination angle from 0° to 90° weakens convection and reduces heat transfer by nearly 77%. Magnetic field strengthening (Ha = 0–45) decreases the Nusselt number by 20–55% depending on the barrier temperature. Among all tested conditions, the highest thermal performance (maximum heat transfer and minimum entropy generation) occurs when using a pseudo-plastic fluid (n = 0.75), exhibiting high wall conductivity (TCR = 50) and heat absorption (HAPC = −5), a cold obstacle (${\mathsf{\theta }}_{\mathrm{b}}=0$), and zero inclination (λ = 0°), as well as in the absence of the magnetic field effects. These quantitative insights highlight the controllability of the conjugate heat transfer and irreversibility in the power-law fluids under coupled magnetothermal conditions. Full article

This study investigated the effects of pH (3, 5, 7, 9, 11) on the structure–activity relationship and stability mechanism of Pickering emulsions stabilized by the gorgon euryale starch–quinoa protein complex. Analyses were performed using reverse compression test, rheology, thermal stability assessment, atomic force microscopy (AFM), and low-field nuclear magnetic resonance (LF-NMR) measurements. Reverse compression test showed that the emulsion at pH 3 exhibited the highest hardness and consistency, but the weakest cohesiveness. Rheological measurements revealed that all emulsions displayed shear-thinning behavior, the emulsion at pH 3 had the highest shear stress and apparent viscosity, while that at pH 11 showed the lowest viscosity due to the destruction of macromolecular structures. Thermal stability assessment indicated that the emulsion at pH 3 did not undergo significant stratification even at 60 °C, whereas the stability of emulsions decreased between pH 5–9. Microscopic analyses (optical microscopy, AFM, and LF-NMR) further confirmed that the emulsion at pH 3 had fine, uniform droplets, strong water-binding capacity, and an interfacial film with a “dense protrusion” structure. This study provides a basis for the environmental adaptability design of functional emulsions and contributes to the high-value utilization of gorgon euryale and quinoa resources. Full article