non-Newtonian Behavior Research Articles

Impact of choline choride and sugar natural deep eutectic solvents on structure and functionality of treebean (Parkia timoriana) seed protein

This study explores the impact of natural deep eutectic solvents (NADES) on the structure and functionality of treebean (Parkia timoriana) seed protein, a novel approach to enhancing protein stability and functionality for sustainable bioprocessing. The research aims to evaluate the dynamic interactions between protein and choline chloride-sugar-based NADES, focusing on their effects on thermal properties, emulsification behaviour, and rheological characteristics. NADES were formulated using different sugars, and protein-NADES dispersions were analysed for their physicochemical and functional properties. Key findings include improved thermal stability, with sorbitol-based NADES showing the highest onset temperature (124.2 °C) and peak degradation temperature (330 °C), indicative of enhanced resistance to high-temperature processing. The sorbitol-NADES-protein dispersion also exhibited superior emulsification activity (50.42%) and stability (42.55%) compared to other formulations. Rheological analysis demonstrated non-Newtonian shear-thinning behaviour, with sorbitol-NADES providing the highest zero-shear viscosity (14.32 mPa s) and relaxation time (3.17 s). These results highlight the ability of NADES to stabilize protein structures while maintaining functionality under processing conditions. The novelty of the study lies in demonstrating the potential of NADES to sustainably enhance the structural and functional attributes of plant proteins, paving the way for innovative applications in food and bioprocessing industries. By employing green solvents, this study presents a sustainable solution for high-temperature food processing, addressing environmental concerns associated with conventional solvents.

Analytical simulation of mixed convective Williamson nanofluid flow above a stretched Riga plate considering viscous dissipation effects

This work examines, accounting for viscous dissipation, an analytical simulation of mixed convection heat transfers in a Williamson blood base nanofluid flow on a stretched Riga plate (RP). The Lorentz force, which influences fluid dynamics, is produced by the alternating magnetic fields that comprise the RP. The flow characteristics are further complicated by the blood base Williamson nanofluid’s (WN) non-Newtonian behavior. The governing partial differential equations (PDEs) for momentum and energy are transformed into a set of nonlinear ordinary differential equations (NODEs) by similarity transformations. We solve these equations analytically using the homotopy analysis method (HAM). We investigate in detail how the temperature and velocity profiles (VPs) are affected by significant parameters as the Williamson parameter (WP), viscous dissipation, volume friction of nanoparticles, modified Hartmann number (MHN), heat generation parameter and Biot number (BN). The findings show that the thermal conductivity (TC) of nanoparticles is increased, improving the efficiency of heat transfer. Moreover, a Lorentz force generated by the RP considerably alters the temperature and flow fields. With regard to the design and optimization of thermal systems utilizing complex boundary conditions (BCs) and non-Newtonian nanofluids, this work offers significant new insights.

Optimizing bioconvective heat transfer with MHD Eyring–Powell nanofluids containing motile microorganisms with viscosity variability and porous media in ciliated microchannels

Purpose This paper aims to optimize bioconvective heat transfer for magnetohydrodynamics Eyring–Powell nanofluids containing motile microorganisms with variable viscosity and porous media in ciliated microchannels. Design/methodology/approach The flow problem is first modeled in the two-dimensional frame and then simplified under low Reynolds number and long wavelength approximations. The numerical method is used to examine the impact of thermal radiation, temperature-dependent viscosity, mixed convection, magnetic fields, Ohmic heating and porous media for velocity, temperature, concentration and motile microorganisms. Graphical results are presented to observe the impact of physical parameters on pressure rise, pressure gradient and streamlines. Findings It is observed that the temperature of nanofluid decreases with higher values of the viscosity parameter. It is absolutely in accordance with the physical expectation as the radiation parameter increases, the heat transfer rate at the boundary decreases. Nanoparticle concentration increases by increasing the values of bioconvection Rayleigh number. The density of motile microorganisms decreases when bioconvection Peclet number is increased. The velocity of the nanofluid decreases with higher value of Darcy number. With increase in the value of bioconvection parameter, the flow of nanofluid is increased. Originality/value The bioconvective peristaltic movement of magnetohydrodynamic nanofluid in ciliated media is proposed. The non-Newtonian behavior of the fluid is described by using an Eyring–Powell fluid model.

A computational investigation using the nonNewtonian Sisko model and finite element analysis to determine blood flow characteristics in trapezoidal stenosed arteries

Arterial stenosis, a narrowing of the artery, significantly impacts blood flow dynamics and heat transfer. Although this phenomenon has been studied broadly, there is very less study about the complex interactions between nonNewtonian blood behavior, complicated artery geometry and temperature fluctuations. Using the Sisko model to represent the nonNewtonian blood nature in a trapezoidally stenotic artery, this study looks to clarify impact of arterial stenosis on blood flow dynamics. This study specifically looks into the temperature, pressure and velocity profiles in these circumstances. A Sisko structural equation-based mathematical model is created to represent blood flow via a trapezoidally stenosed artery. The governing equations which include momentum, energy conservation and continuity are numerically solved with the proper boundary conditions. Under various parametric values, the study shows complex fluctuations in the temperature, pressure and velocity profiles within the stenosed artery. These profiles are greatly impacted by the nonNewtonian conduct of blood, especially in the stenosis zone. It is discovered that the degree of stenosis is important in determining heat transmission, shear stress and flow resistance. Important new information about the hemodynamics and thermal behavior of blood in stenosed arteries is provided by this study. The results increase our understanding of vascular disorders and have the potential to guide the creation of innovative diagnostic and medical techniques.

ANALYSIS OF RHEOLOGICAL PROPERTIES IN PE FIBER-REINFORCED FLY ASH GEOPOLYMER FOR ADDITIVE MANUFACTURING

The leading edge of construction advancements is represented by 3D printing which creates durable and elaborate structures and minimizes resource wastage. As a viable substitute for regular cement materials highlights the ecological benefits and strong mechanical traits of fly ash geopolymers. This study investigates how the addition of polyethylene (PE) fibers alters these properties and how varying concentrations influence the flow behavior and capability of producing the composite material. The analysis of non-Newtonian behavior in these fiber-reinforced geopolymers is conducted using the Herschel-Bulkley model. By precisely measuring critical rheological factors such as viscosity and flow behavior researchers can evaluate how they influence 3D printing processes. This research reveals that adding PE fibers boosts the material’s strength and improves resistance against cracking while also elevating the viscosity and yield stress that can hinder its passage through the printer’s nozzle. An optimal blend of fiber content emerges from controlled tests that align increased durability with controllable extrusion flow and structure reliability. The results offer deep practical applications that reveal methods for producing geopolymers that can maintain strength while meeting the exacting requirements of 3D printing methods. Research deepens the grasp of how adding fibers alters the properties of geopolymers and enriches the overall dialogue on green building materials. It opens doors for subsequent analysis of complex fiber systems and creative additive practices to boost the effectiveness and resilience of construction materials in practical use.

Development of a Microfluidic Viscometer for Non-Newtonian Blood Analog Fluid Analysis.

The incidence of stroke is on the rise globally. This affects one in every four individuals each year, underscoring the urgent need for early warning and prevention systems. The existing research highlights the significance of monitoring blood viscosity in stroke risk evaluations. However, the current methods lack the precision to measure viscosity under low shear rate conditions (<100 s⁻¹), which are observed during pulsatility flow. This study addresses this gap by introducing a novel microfluidic platform designed to measure blood viscosity with high precision under pulsatility flow conditions. The systolic blood viscosity (SBV) and diastolic blood viscosity (DBV) can be differentiated and evaluated by using this system. The non-Newtonian behavior of blood is captured across specific shear rate conditions. The platform employs a meticulously designed microarray to simulate the variations in blood viscosity during pulsation within blood vessels.The results demonstrate an impressive accuracy of 95% and excellent reproducibility when compared to traditional viscometers and rheometers and are within the human blood viscosity range of 1-10 cP. This monitoring system holds promise as a valuable addition to stroke risk evaluation methods, with the potential to enhance prediction accuracy.

Investigation of Rheological and Flow Properties of Buckwheat Dough with and Without Xanthan and Guar Gums for Optimized 3D Food Printing Across Temperature Variations.

Buckwheat (Fagopyrum esculentum) is a gluten-free crop valued for its protein, fiber, and essential minerals. This study investigates the rheological properties of buckwheat (BW) dough, both with and without the addition of gums (no gum, guar (GG), xanthan (XG)), at varying barrel temperatures (25, 55, and 85 °C) of the rheometer and at different water content levels (45, 50, and 55% w/w) to optimize dough formulations for 3D food printing. Using high shear stress capillary tests, the consistency coefficient (K) and flow behavior index (n) were measured. The results indicated that GG significantly increases the apparent viscosity of buckwheat dough across shear rates ranging from 200 to 2000 s-1, under all temperature and water content conditions. XG also enhanced viscosity but to a lesser extent at moderate temperatures (55 °C, 85 °C). All BW dough formulations exhibited a non-Newtonian shear-thinning behavior, crucial for 3D printing applications. In addition, computational fluid dynamics (CFD) simulations were conducted to analyze the extrusion process of BW dough formulations (50% W, 50% W + XG, and 50% W + GG), focusing on shear rate, viscosity, and pressure distribution. The simulations demonstrated that shear rates increased as the dough moved through the nozzle, while viscosity decreased, facilitating extrusion. However, gum-added formulations required higher pressures for extrusion, indicating an increased difficulty in dough flow. The study highlights the complex interactions between temperature, water content, and additive type on the rheological properties of buckwheat dough, while also incorporating CFD simulations to analyze the extrusion process. These insights provide a foundation for developing nutrient-dense, gluten-free 3D-printed foods tailored to specific dietary needs.

Design of Trabecular Bone Mimicking Voronoi Lattice-Based Scaffolds and CFD Modelling of Non-Newtonian Power Law Blood Flow Behaviour

Design of Trabecular Bone Mimicking Voronoi Lattice-Based Scaffolds and CFD Modelling of Non-Newtonian Power Law Blood Flow Behaviour

Study on thermal elastohydrodynamic lubrication of face gear pairs with low sliding ratio

The relative sliding interaction between tooth surfaces has a significant effect on the lubrication efficiency. In this study, the non-Newtonian characteristic is taken into consideration when examining the point contact thermal elastohydrodynamic lubrication (TEHL) behavior of a low sliding ratio (LSR) face gear pair. By using the instantaneous rotation axes method, tooth contact analysis (TCA) was carried out. Meanwhile, a combination of the Hertz contact model and finite element analysis (FEA) was adopted in order to conduct load tooth contact analysis (LTCA). Subsequently, a TEHL model for the face gear pair was established, incorporating the non-Newtonian behavior of the lubricant. Multi-grid (M-G) and Gauss-Seidel (G-S) methods were employed to improve the computational efficiency as well as convergence accuracy for relatively dense grids. The lubrication behaviors of LSR face gears and traditional face gears under full film lubrication conditions were compared. Additionally, the lubrication characteristics of face gears with the machined three-dimensional morphology were also clarified. The model and computations were validated through comparison with literature data. The findings reveal that improving contact performance can be achieved by designing gear pairs with low sliding ratios.

Direct simulations of bedrock core and cuttings transport phenomena in reverse circulation drilling

Polar drilling is essential for obtaining ice and bedrock samples, providing critical insights into climate and geological history. The reverse circulation drilling method, utilizing a dual-wall drill pipe, presents a stable and efficient strategy. Nonetheless, the intricate dynamics involving drilling fluids, rock cuttings and cores necessitate sophisticated modeling to elucidate the underlying mechanism and optimize drilling efficiency. To address this, we developed a multiphase flow model that accounts for non-Newtonian fluid behavior, turbulence, particle dynamics, and fluid–structure interactions, enabling a thorough assessment of various operational parameters. The model's temporal–spatial sensitivity was evaluated, and its accuracy was confirmed by comparison with three different sets of experimental data. A detailed parametric investigation was then conducted to systematically assess the effects of various parameters, including the non-Newtonian behavior and inlet velocity of the drilling fluid, the rate of penetration, and the dimensions of the cuttings and core. The simulation results indicate that the non-Newtonian behavior of the drilling fluid has an non-negligible effect on the transport efficiency of both cuttings and core. An increase in the fluid inlet velocity leads to faster transport, albeit at the cost of higher pump pressure. The rate of penetration has a minor influence on the core transportation but largely affects the cutting transportation. More interestingly, larger cuttings demonstrate enhanced transport efficiency, attributed to a more uniform velocity distribution. Furthermore, the core diameter plays a pivotal role in transport efficiency by significantly altering the fluid dynamics, whereas the core length has a negligible effect. These results may have direct applications for optimizing polar drilling operations, potentially leading to enhanced drilling efficiency, reduced drilling costs, and informing future drilling technology advancements.

Walters B’ hybrid nanofluid flow with Marangoni convection

The proposed investigation is based on the applications of Walters B' viscoelastic model for the magnetohydrodynamic (MHD) free convection of hybridised fluid flow over a vertically expanding surface embedding in porous substances. The traditional base fluid water is comprised of Al2O3 and Cu nanoparticles for the preparation of hybrid nanofluid and the system is analyzed under the influence of Marangoni surface constraints. Further, the influence of radiating heat, Joule and Darcy dissipation along with non-uniform heat source energies the transport phenomena. These assumptions are particularly relevant in advanced cooling systems, energy-efficient devices, material processing, etc. For the memory effects in polymer-based fluid, the Walters B' viscoelastic model is applied to examine the non-Newtonian behavior of the hybrid nanofluid. The porous medium enhances the permeability of the fluid while the magnetic field regulates fluid motion and is useful in magnetic drug targeting and geothermal energy extraction. The standard conservation equations are transmuted into an ordinary set of equations implementing similarity functions and then a numerical approach is implemented for the solution. In particular case exact solution for the momentum profile is obtained and compared with earlier investigation. The impact of distinct factors affecting the heat transfer rate is presented graphically and described briefly. The findings demonstrate that incorporating composite nanoparticles greatly improves thermal performance, with Marangoni convection and dissipation playing key roles in the heat transfer process. Moreover, the heat transport rate enhances for the inclusion of the thermal radiation.

Response surface optimisation on Non-Uniform shapes ternary hybrid nanofluid flow in stenosis artery with motile gyrotactic microorganisms

This work used ternary hybrid nanofluids containing motile gyrotactic microorganisms and irregularly shaped platelet, cylindrical, and spherical nanoparticles to evaluate heat transport in a stenosis artery with volume fractions of Cobalt φ1=0.01, Silver φ2=0.01, and Gold φ3=0.01. The proper self-similarity variables are used to convert the fluid transport equations into ordinary differential equations., which the BVP4C then solves in MATLAB. We analyse the effects of various parameters, including curvature, magnetic intensity, thermal radiation, and non-Newtonian behaviour, regarding Nusselt numbers, temperature profiles, skin friction, and velocity distribution. The study reveals that higher curvature enhances convective heat transfer despite initial resistance due to flow constriction, while magnetic fields stabilise flow patterns and improve heat transfer via nanoparticle alignment. Thermal radiation amplifies heat transfer by reducing boundary layer thickness and enhancing energy absorption. The non-linear relationship between magnetic intensity, thermal radiation, and the Eckert number that our results reveal emphasizes the need for more vital magnetic fields to sustain stability and effective heat transfer as thermal radiation rises. This work offers valuable information for improving nanofluid, automotive, and biomedical engineering heat transfer mechanisms. It can improve heat therapy, targeted medication administration, and diagnostic imaging in biomedicine. It provides advancements in gasoline additives, lubricants, and engine cooling systems for the automotive industry. It can improve solar energy systems, microfluidics, and heat transfer systems in nanofluid engineering.

Characterization of Mucilage from Opuntia cochenillifera Cladodes: Rheological Behavior, Cytotoxicity, and Antioxidant Potential

This study explores the extraction of mucilage from cladodes of O. cochenillifera, an underutilized species of the Opuntia genus, in water at room temperature and under continuous stirring, avoiding harsh solvents and high temperatures to preserve its physicochemical and biological properties. Biological safety evaluation of the mucilage revealed cell viability exceeding 70% at various concentrations (0.05 – 5000µg/mL) through 3-[4,5-dimethylthiazol-2-yl]-2,5 diphenyl-tetrazolium (MTT) and sulforhodamine B (SRB) assays. However, the analyses of antioxidant potential revealed insufficient protective effects against oxidative stress across all tested concentrations, indicating the need for a more complex study to understand the sample's antioxidant capacity fully. Additionally, a non-Newtonian fluid behavior was observed during rheological studies and was characterized by shear thinning. Significant variations in viscosity were noted in response to temperature, pH, and concentration, highlighting the mucilage's sensitivity to environmental and compositional conditions. This work not only expands the understanding of the biological viability and physical properties of O. cochenillifera mucilage but also highlights its potential application as a multifunctional, sustainable, and safe biopolymer for the food, cosmetic, and biomedical industries. These results establish a robust scientific foundation for future investigations into the development of natural and biocompatible additives, significantly contributing to the advancement of sustainable and environmentally friendly alternatives across multiple industrial sectors.

Mobilization of poly- and perfluoroalkyl substances (PFAS) from heterogeneous soils: Desorption by ethanol/xanthan gum mixture

Remediating soils contaminated by per- and polyfluoroalkyl substances (PFAS) is a challenging task due to the unique properties of these compounds, such as variable solubility and resistance to degradation. In-situ soil flushing with solvents has been considered as a remediation technique for PFAS-contaminated soils. The use of non-Newtonian fluids, displaying variable viscosity depending on the applied shear rate, can offer certain advantages in improving the efficiency of the process, particularly in heterogeneous porous media. In this work, the efficacy of ethanol/xanthan mixture (XE) in the recovery of a mixture of perfluorooctane sulfonate (PFOS), perfluorooctanoic acid (PFOA), perfluorohexane sulfonate (PFHxS), and perfluorobutane sulfonate (PFBS) from soil has been tested at lab-scale. XE’s non-Newtonian behavior was examined through rheological measurements, confirming that ethanol did not affect xanthan gum’s (XG) shear-thinning behavior. The recovery of PFAS in batch-desorption exceeded 95 % in ethanol, and 99 % in XE, except for PFBS which reached 94 %. 1D-column experiments revealed overshoots in PFAS breakthrough curves during ethanol and XE injection, due to over-solubilization. XE, (XG 0.05 % w/w) could recover 99 % PFOA, 98 % PFBS, 97 % PFHxS, and 92 % PFOS. Numerical modeling successfully reproduces breakthrough curves for PFOA, PFHxS, and PFBS with the convection-dispersion-sorption equation and Langmuir sorption isotherm.

Formation of Ferrogabbro Through Fe-Ti Oxide Accumulation Under Moderate Oxidation Conditions: Insights from the Dashanshu Intrusion in the Emeishan Large Igneous Province, SW China

The mechanism of iron enrichment in ferrogabbro remains a controversial subject. This study provides valuable insights derived from the Dashanshu intrusion, located in the Emeishan Large Igneous Province in southwestern China, which features ferrogabbro with a notably high iron content (total Fe2O3 reaching up to 21.6 wt.%). The ferrogabbro samples exhibit distinctive petrographic features, including the early crystallization of plagioclase prior to pyroxenes, amphibole replacing pyroxenes, and magnetite–ilmenite intergrowth filling the interstices between plagioclase and pyroxenes. A quantitative mineral analysis based on micro-X-ray fluorescence element mapping reveals a positive correlation between Fe-Ti oxides and bulk-rock iron contents, suggesting that the formation of ferrogabbro is primarily attributed to the accumulation of Fe-Ti oxides. Petrographic characteristics combined with oxygen fugacity determinations indicate that the primitive magma had a low content of water and was moderately oxidized (ΔFMQ − 0.13 to ΔFMQ + 1.35). These conditions suppress the early crystallization of Fe-Ti oxides, thereby allowing for an enrichment of iron in the residual magma. Following the crystallization of plagioclase and pyroxenes, increased water content—evidenced by amphibole replacing pyroxenes—triggers extensive crystallization of Fe-Ti oxides. Due to their late-stage crystallization, these oxides do not settle within the magma, which possesses a high crystallinity (&gt;50%) and consequently exhibits non-Newtonian fluid behavior. This results in the localized accumulation of Fe-Ti oxides and the formation of a ferrogabbro layer. However, the late-stage crystallization of Fe-Ti oxides also impedes the sinking and flow-sorting processes that are essential for the development of economically valuable Fe-Ti oxide layers. This may account for the lack of an economically valuable Fe-Ti oxide layer within the Dashanshu intrusion.

Microfluidic Study of Application of Nanosuspension with Aluminum Oxide Nanofibers to Enhance Oil Recovery Factor During Reservoir Flooding

The paper presents the results of a comparative microfluidic study of the oil displacement process from a microfluidic chip simulating rock. Suspensions of spherical nanoparticles of silicon oxide (22 nm) and aluminum oxide (11 nm), as well as aluminum oxide nanofibers (8.7 nm in diameter and with an aspect ratio of 58), were used as displacing liquids. The nanofibers represent a unique new-generation crystalline material with a high aspect ratio. This work presents the first consideration of the use of aluminum oxide nanofibers as an additive for enhanced oil recovery. The comparative analysis has demonstrated that the addition of nanofibers can markedly enhance the oil recovery factor relative to the addition of spherical nanoparticles, other things being equal. Thus, in particular, it was demonstrated that the addition of nanofibers into the system allows for the greatest enhancement of the oil recovery factor, reaching a value of 25%, whereas the addition of spherical nanoparticles results in a maximum increment of approximately 10%. This is due to the fact that nanofiber additives have a tenfold stronger effect on the viscosity of nanosuspensions compared to similar additives of spherical particles. Nanosuspensions of aluminum oxide nanofibers exhibit non-Newtonian behavior at low concentrations. This opens the possibility of their extensive use in enhanced oil recovery.

Antimicrobial and degradable all-cellulose composite for functional and sustainable food packaging

The investigation of environmentally friendly and sustainable replacement materials is consistently prompted by the mounting environmental concern over plastics derived from petrochemicals. Compared with fossil oil derived chemicals and materials, cellulose is more readily available, less expensive, and biodegradable. Herein, all-cellulose composite films with excellent biodegradability and antimicrobial activities were prepared for sustainable food package. The all-cellulose films were prepared by a simple solution cast method of amino cellulose and carboxymethyl cellulose mixture. Rheological studies suggest typical non-Newtonian and shear thinning behavior of the all-cellulose solution associated with strong intermolecular electrostatic interactions. Such composite results in package films with amorphous structure, and uniform, dense and smooth morphology. Properties explorations indicated that the all-cellulose composites films exhibited better mechanical properties, water vapor and oxygen barrier properties than conventional synthetic plastic packages. Besides, the all-cellulose films showed excellent antimicrobial activity, and biodegradability. When applied as shrimp package, the all-cellulose composite films effectively extended shelf-life of shrimp by inhibition of microbial and oxidative deterioration of shrimp meat. This study provides a feasible approach to syntheze biodegradable and antimicrobial functional food package from cellulose in replacing of traditional synthetic plastic films.

The impact of blood viscosity modeling on computational fluid dynamic simulations of pediatric patients with Fontan circulation.

For univentricular heart patients, the Fontan circulation presents a unique pathophysiology due to chronic non-pulsatile low-shear-rate pulmonary blood flow, where non-Newtonian effects are likely substantial. This study evaluates the influence of non-Newtonian behavior of blood on fluid dynamics and energetic efficiency in pediatric patient-specific models of the Fontan circulation. We used immersed boundary-lattice Boltzmann method simulations to compare Newtonian and non-Newtonian viscosity models. The study included models from twenty patients exhibiting a low cardiac output state (cardiac index of 2 L/min/m2). We quantified metrics of energy loss (indexed power loss and viscous dissipation), non-Newtonian importance factors, and hepatic flow distribution. We observed significant differences in flow structure between Newtonian and non-Newtonian models. Specifically, the non-Newtonian simulations demonstrated significantly higher local and average viscosity, corresponding to a higher non-Newtonian importance factor and larger energy loss. Hepatic flow distribution was also significantly different in a subset of patients. These findings suggest that non-Newtonian behavior contributes to flow structure and energetic inefficiency in the low cardiac output state of the Fontan circulation.

Interaction of gum acacia and natural deep eutectic solvents: Effect on conductivity, thermal stability, compression, and stress relaxation properties

The present study discussed the structure-function relationships of gum acacia and natural deep eutectic solvents (NADES) through interactive effects on physical, chemical, and rheological properties. Lactic acid, malic acid, glucose, and fructose-based NADES were prepared using the heating and stirring method. These NADES were mixed with 5 and 7% gum acacia to obtain dispersion. The NADES-gum acacia dispersion was analysed using FTIR, DSC, compression extrusion test and rheometer to measure the change in physical, thermal, and rheological characteristics. The gum acacia dispersion with lactic acid, and malic acid NADES showed low pH with high conductivity and density. The dispersion with sugar NADES showed higher thermal stability than dispersion with acid NADES. FTIR showed that there was a strong interaction between gum acacia and NADES. The dispersion having sugar NADES showed higher peak force and energy than acid NADES. The dispersion showed non-Newtonian and pseudo-plastic behaviour and experimental data well fitted with Carreau-Yasuda model. The gum acacia with sugar NADES dispersions exhibited high zero share viscosity and relaxation time. Therefore, the present study manifested a tailoring approach for gum acacia dispersion according to the purpose to use.

FSI modeling and simulation of blood viscosity impacts on cavitation in mechanical heart valves

Heart valve replacements are critical for patients with valve malfunctions, and the tri-leaflet mechanical heart valve (tMHV) is one of the most durable options available. The tMHV is used to replace malfunctioning heart valves, restoring normal blood flow with exceptional durability, often lasting up to 20 years without needing replacement. This durability makes tMHVs particularly suitable for patients under 60. However, mechanical issues like cavitation can undermine the valve's functionality, posing risks to both its longevity and the overall efficacy of cardiovascular treatments. While previous studies have investigated some aspects of cavitation in these valves, the combined effects of blood viscosity and fluid-structure interaction (FSI) on cavitation dynamics remain insufficiently explored.This work models and numerically simulate the influence of blood viscosity on cavitation within tMHVs, using FSI principles. A detailed geometric model of the tMHV was developed, incorporating experimental data and non-Newtonian fluid behaviour to accurately replicate blood flow. Simulations were conducted in ANSYS Fluent R1® using a transient solver to capture the dynamic FSI, with the Carreau-Yasuda model representing blood's shear-dependent viscosity. Cavitation was observed at pressures as low as 4.5 Pa—well below the 15-20 Pa range typically reported—indicating a higher vulnerability than previously recognized. The simulations further showed significant vapour bubble formation, with the maximum vapour volume fraction reaching 0.953. High-speed leakage flows, peaking at 11 m/s during valve closure, were also noted, considerably exceeding velocities observed in earlier studies.These findings demonstrate that cavitation occurs when blood pressure drops below vapour pressure, causing vapour bubbles to form. These bubbles generate shock waves that can damage the valve surfaces and surrounding tissue. Insights from this study will aid in the design of next-generation tMHVs with optimised flow dynamics, potentially reducing cavitation risks and enhancing patient outcomes by minimising valve-associated complications.