non-Newtonian Systems Research Articles

Effects of Newtonian Heating on MHD Jeffrey Hybrid Nanofluid Flow via Porous Medium

In recent years, hybrid nanoparticles have gained significant attention for their ability to enhance thermal conductivity in various fluid systems, making them effective heat transport catalysts. Despite advancements in thermal fluid technology, a gap remains in understanding how hybrid nanoparticles interact within non-Newtonian Jeffrey fluid systems, particularly under complex boundary conditions like Newtonian heating. The present study aims to shed light on the effect of hybrid nanoparticles (alumina and copper) incorporated into a Jeffrey fluid model on flow and heat transport, considering them as heat transport catalyst and subject to Newtonian heating to optimize thermal efficiency. An exponentially accelerated plate is used to induce the fluid flow, taking into account the effects of porosity, MHD, and thermal radiation. The examined fluid exhibits an unsteady one-dimensional flow, formulated by deriving partial differential equations, which are subsequently transformed into ordinary differential equations using suitable non-dimensional variables and the Laplace transformation. This research distinguishes itself by presenting a novel mathematical model for MHD Jeffrey hybrid nanofluid, accounting for porosity and Newtonian heating effects. The inverse of Laplace is used to generate the exact solutions for velocity and temperature profiles, which is not explored in existing literature. Graphical representations are generated using Mathcad, depicting the velocity and temperature distributions. A comparison with prior study from the literature demonstrates strong agreement between our findings and theirs. The findings indicate that the velocity and temperature profiles of the hybrid nanofluid are higher with Newtonian heating than without it. Additionally, an increase in the Grashof number, radiation, acceleration, and porosity parameters also leads to an enhanced velocity profile.

Sour taste perception in fluids: The impact of sweet tastant, fluid viscosity, and individual salivary properties

Binary taste perception is widely studied in aqueous solutions but less investigated in non-Newtonian fluid systems. In this study, the effect of sweet tastants on the dynamic sour taste perception in thickened fluids and its underpinning oral processing factors were investigated. Subjects were tested for taste thresholds and salivary biochemical properties. By using hydroxypropyl methylcellulose (HPMC) as a thickening agent, subjects conducted sour taste evaluation, with and without maltose and/or HPMC, using descriptive sensory analyses. A simulated fluid shear elicited by fixed-frequency mastication was applied on thickened fluid sample oral processing during time-intensity sour taste evaluation. Results showed that adding maltose to fluid samples enhanced sour taste perception, and increasing fluid viscosity generally suppressed perceived maximum sour taste. Moreover, subjects with lower sour taste sensitivity and higher salivary buffering capacity reported overall lower sour taste intensity in most samples, validating the hypothesis that salivary properties importantly affect sour taste perception.

Investigating the magnetohydrodynamics non-Newtonian fluid movement on a tensile plate affected by variable thickness with dufour and soret effects: Akbari Ganji and finite element methods

Significant progress in the investigation of non-Newtonian Williamson and Casson boundary layer flow has led us to explore the extension of non-Newtonian Williamson and Casson hydromagnetic boundary layer flow in an electrically conductive fluid subjected to a strong magnetic field and a uniform thermal field. This study is divided into two interconnected parts. The first part converts the nonlinear system governing the Partial Differential Equations into a simpler, nonlinear, ordinary differential equation. It is then analyzed using the Akbari Ganji method (AGM). The output data from the first part, solved using AGM, is compared and evaluated with the output data from the second part, solved with the assistance of finite element (FEM) methods. This research validates previous works with current methodologies. Subsequently, changes in temperature and concentration parameters, influenced by variations in magnetic parameters, are obtained and analyzed through three-dimensional charts. Upon reviewing the results, it is observed that the distribution of concentration and temperature is dependent on the distribution of the magnetic parameter, with an increase in concentration and temperature being influenced by the rise in the magnetic parameter. Other parameters are also examined, each of which is elaborated upon below. The effects of Bi1, Sr, and Sc parameters on temperature are investigated, and design points for achieving optimal and effective design are presented in the graph. Some applications of magnetohydrodynamics and non-Newtonian fluids include improving fluid pumping technologies. Using magnetohydrodynamics in non-Newtonian fluid pumping systems can help improve efficiency and reduce energy costs. Additionally, enhancing the efficiency of heat transfer systems using magnetohydrodynamics can help improve efficiency and reduce energy losses in these systems.

Magnetohydrodynamic influence on fractional nanofluid convection in infinite vertical porous media with constant heat flux

This study investigates the complex dynamics governing free convection flow in nanofluids under Magnetohydrodynamics (MHD) within a porous medium along an infinite vertical surface. We specifically focus on scenarios involving constant and uniform heat flux as well as heat sources. The governing equations, incorporating the Boussinesq approximation, continuity, and momentum equations, are formulated and solved using Caputo-Fabrizio derivatives and Laplace transforms. This comprehensive approach integrates the Boussinesq approximation and Caputo-Fabrizio fractional derivatives, while the use of Laplace transforms enables precise analytical solutions. Additionally, our investigation highlights the significant impact of nanometer-sized copper particles on fluid properties, transforming the behavior from Newtonian (water-like) to non-Newtonian. This transformation profoundly affects thermal conductivity and velocity behavior within the system. Overall, this research establishes a robust foundation for future studies and provides a framework for exploring non-Newtonian nanofluid systems in the context of MHD-driven free convection flow.

Modeling and analysis of particle behavior in fluidized bed bioreactors during non-Newtonian sewage treatment

The stability of biofilms attached to support particles plays a crucial role in fluidized bed bioreactors (FBBRs) when treating non-Newtonian sewage. Biofilm instability is governed by particle-particle (P-P) and particle-wall (P-W) collisions. This paper presents a numerical study of particle behavior in a FBBR using a combined approach of computational fluid dynamics (CFD) and discrete element method (DEM) tailored for non-Newtonian flow systems. Following validation, the CFD-DEM model is utilized to quantify the FBBR performance regarding bed expansion, void fraction distribution, and P-P/W interactions. The impacts of three variables are examined, including sewage superficial velocity and two rheological properties, i.e., sewage temperature and solid concentration. The results reveal that increasing sewage superficial velocity and sewage solid concentration or decreasing sewage temperature, leads to a transition in particle flow from symmetrical to asymmetrical in the radial direction, along with a circulating flow at the lower part of the bed. The relationships between the variables and the bed expansion, uniformity, and P-P/W interactions are also established, identifying optimum conditions to enhance bed uniformity and reduce P-P/W interactions. Overall, the findings demonstrate the value of the CFD-DEM model for understanding, designing, and optimizing FBBRs.

RHEOLOGICAL FEATURES OF LIQUID IN MICROCRACKED CHANNELS WITH THE “MICROCRACK-LIQUID” EFFECT DISPLAYED

Based on experimental and theoretical studies in plane-radial and plane-parallel microcracks, a previously unknown pattern called “microcrack-liquid” effect was established for the first time, that when viscous liquids move in a microcrack at h<hcr, anomalous properties appear, and when anomalous liquids move, rheological parameters increase, at h>hcr these effects disappear. It was revealed that the reason for the manifestation of anomalous properties of Newtonian liquids and the enhancement of the rheological properties of non-Newtonian systems when they move in microcapillary cracks is the new microcrack effect of the “microcrack-liquid” system. The established critical values of crack opening for the studied viscous oils are 160 μm at a temperature of 303 K. Keywords: microcrack opening, non-Newtonian fluids, ultimate shear stress, structural viscosity, microcrack-liquid effect.

Emollients with natural emulsifier Olivem 1000 as topical formulations for urea or sodium hyaluronate

Xerosis is one of the common dermatological problems. Preparations recommended for daily care of the dry skin are emollients. Emollient preparations demonstrate a moisturizing effect, they soften and smoothen the skin, keep water in the epidermis, supplement lipids of skin upper layers and protect from external harmful agents. The purpose of this study was to develop and characterize emollients containing natural emulsifier Olivem 1000 as topical delivery systems for urea or sodium hialuronate. Physicochemical and mechanical properties of designed formulations were evaluated. Moreover, ex vivo adhesion study on the hairless mice skin as a model of adhesive layer was carried out and in vivo preliminary assessment of transepidermal water loss (TEWL) was performed. Prepared emollient formulations were characterized by smooth consistency, they were easily spreadable on the skin surface and showed no phase separation. Formulations containing xanthan gum as a thickening agent were characterized by higher viscosity, hardness, cohesiveness and adhesiveness values. Prepared emollients showed thixotropic properties and they were classified as non-Newtonian shear thinning systems. All prepared emollients demonstrated bioadhesive properties. The analysis of TEWL showed that the greatest decrease in the TEWL value was noted in the case of emollient containing sodium hyaluronate which was applied to the person with the skin described as “the skin in a very poor condition”. The results of the conducted research indicate that developed emollients containing natural emulsifier Olivem 1000 seem to be a promising form of care preparations for topical use in case of chronic dryness of the skin.

Prediction and Output Estimation of Pattern Moving in Non-Newtonian Mechanical Systems Based on Probability Density Evolution

Prediction and Output Estimation of Pattern Moving in Non-Newtonian Mechanical Systems Based on Probability Density Evolution

Computation of non-Newtonian quadratic convection in electro-magneto-hydrodynamic (EMHD) duct flow with temperature-dependent viscosity

Motivated by novel developments in smart non-Newtonian thermal duct systems, a theoretical study has been presented in this article for electro-magneto-hydrodynamic (EMHD) buoyancy-driven flow of a fourth-grade viscoelastic fluid in a vertical duct with quadratic convection. The viscosity of the fourth-grade fluid model is assumed to be temperature-dependent, and the Reynolds exponential model is deployed. Viscous heating and Joule dissipation effects are included. The duct comprises a pair of parallel electrically insulated vertical flat plates located a finite distance apart. Via suitable scaling transformations, a nonlinear boundary value problem is derived for the momentum and heat transport. A homotopy perturbation method (HPM) solution is obtained coded in Mathematica symbolic software. There is a considerable enhancement in wall skin friction with an increment in fourth-grade fluid parameter, Brinkman number, electrical field parameter, thermal buoyancy parameter, and quadratic thermal convection parameter. However, skin friction is strongly reduced with a rise in variable viscosity parameter, Hartmann (magnetic) number, and electromagnetic heat generation to conduction ratio. Nusselt number magnitudes are elevated with increase in variable viscosity parameter, thermal buoyancy parameter, and quadratic thermal convection parameter, whereas they are significantly suppressed with increment in fourth-grade fluid parameter, Brinkman number, and Hartmann magnetic number.

Structural Causes of the Non-Newtonian Behavior of Fluid Systems

This review considers the well-known results of rheological studies, first of all, the viscosity and flow curves of various dispersed and polymer systems. The existing explanations of the causes of non-Newtonian flow are presented. Various rheological models are described, in which a change in viscosity is associated with a change in the structure of a substance. The new structural rheological model proposed by us is a generalization of the Casson and Cross rheological models. Its scope includes various structured systems: suspensions, emulsions, polymer solutions and melts, micellar solutions, and liquid crystals. Our attention was focused on the features of the stationary shear flow of non-Newtonian systems.

Composition development and in vitro evaluation of O/W emulsions based on natural emulsifier Olivem 1000 as tea tree oil carriers

The frequent occurrence of bacterial skin infections makes it necessary to search new solutions. Due to the limited effectiveness of traditional antibacterial agents, novel treatment alternatives are investigated. The use of plant origin compounds seems to be beneficial, because they are usually well tolerated and do not cause as many side effects as synthetic substances. Tea tree oil (TTO) is noted for well-established antimicrobial activity, so it can be used in the treatment of various skin diseases. It is effective against Gram-negative as well as Gram-positive bacteria. The aim of this work was to develop the composition and preparation technology of emulsion with TTO using natural emulsifier Olivem 1000 - combination of cetearyl olivate and sorbitan olivate. The designed formulations were evaluated by testing pH, stability and droplets size of the dispersed phase in the prepared emulsions. The type of emulsions was determined by selective phase staining method. In addition, rheological, mechanical, ex vivo bioadhesive properties of the prepared emulsions were studied and their antibacterial activity against selected strains was estimated. Obtained formulations were non-Newtonian systems, showing a shear-thinning behaviour and thixotropic properties, with proper textural features and beneficial bioadhesive properties. It was also demonstrated that formulations with lower viscosity showed higher antimicrobial efficacy against tested microorganisms and larger zones of inhibition were observed in case of Escherichia coli strains. The results of the study showed that the prepared emulsions appear to be a suitable form of topical administration of TTO.

Research of rheological characteristics of mayonnaise with different varieties of honey added

Determination of food products rheological properties is becoming more and more important for assessing raw materials and finished products quality, as well as for predicting a semi-finished product behavior during processing. The influence of honey variety, rotor speed and homogenization time on mayonnaise rheological properties were studied in this work. The following honey varieties were used: acacia, linden, forest, spring. Refined sunflower oil was used to make mayonnaise. The mechanical process of mayonnaise homogenization was carried out at a rotor speed of 10,000 rpm and 12,000 rpm, for 2 and 4 minutes at room temperature. Mayonnaise with 75% oil phase was prepared according to a traditional recipe without preservatives added. Rheological properties measurements were carried out on a rotary viscometer with concentric cylinders at a temperature of 25 °C. The following parameters were calculated according to the experimental data: apparent viscosity, consistency index and flow index. The research results showed that the type of honey influenced the rheological properties of mayonnaise. They changed as the homogenization process duration and the rotor speed increased. The tested samples of mayonnaise with honey added belong to non-Newtonian systems, a pseudoplastic type of liquid.

Исследование реологических свойств майонеза с нетрадиционным сырьем

Rheological measurements are used in the food industry to determine physical characteristics of raw materials, as well as semi-finished and finished products. We aimed to study the effects of ingredients and homogenization parameters on the rheological properties of mayonnaise prepared with pumpkin and rice oils, as well as various honeys.
 Mayonnaise samples were prepared with non-traditional ingredients, namely cold-pressed pumpkin seed oil, refined rice oil, and four varieties of honey (acacia, linden, forest, and spring). The samples were made in the traditional way on an Ultra Turrax T25 IKA homogenizer (3500–24 000 rpm). The rheological properties of honey and mayonnaise were determined on a Brookfield rotational viscometer.
 Forest honey had the highest viscosity, while linden honey had the lowest viscosity, compared to the other honeys. The sample of mayonnaise with forest honey had the highest effective viscosity (3.427 Pa·s) and consistency (101.26 Pa·sn). The use of whey powder provided mayonnaise with the most optimal rheological parameters. Of all carbohydrates, inulin HD had the best effect on the consistency of mayonnaise, with effective viscosity of 2.801 ± 0.001 Pa·s and a flow index of 0.2630 ± 0.0020. Disaccharides provided mayonnaise with higher viscosity and consistency than monosaccharides. Mayonnaise with fresh egg yolk had higher viscosity (2.656 ± 0.002 Pa·s) and consistency (65.640 ± 0.004 Pa·s) than the samples with other egg products. The rheological characteristics of mayonnaise were also determined by the homogenization time and rotor speed. Increasing the time from 2 to 4 min at 10 000 rpm raised the emulsion’s viscosity and consistency from 6.253 to 8.736 Pa·s and from 77.42 to 134.24 Pa·sn, respectively, as well as reduced the flow index from 0.2628 to 0.1995. The rotor speed of 10 000–12 000 rpm was optimal for mayonnaise with pumpkin and rice oils and honey.
 The studied samples of mayonnaise with pumpkin and rice oils, as well as honey, belong to non-Newtonian systems and pseudoplastic fluids. The empirical flow curves can be adequately described by the Herschel-Bulkley model. Our results can significantly increase the efficiency of mayonnaise production, improve its quality, and reduce production costs.

Insights into the dynamics of non-Newtonian droplet formation in a T-junction microchannel

The non-Newtonian shear-thinning droplet formation mechanism in a T-junction microchannel is experimentally investigated using the aqueous solutions of xanthan gum as the dispersed phase and mineral oil as the continuous phase. Influences of both phase flow rates and polymer concentration on flow regime transition are explored. It is observed that the initial vertical expansion stage is present only for the Newtonian and lower shear-thinning systems. The droplet evolution rate shows the influence of continuous phase flow rate and shear-thinning properties on the dynamics of necking stages, viz., squeezing, transition, pinch-off, and filament thinning. Analysis of Ohnesorge number (Oh) reveals that inertial force dominates in the squeezing stage, whereas viscous and interfacial force control in the filament thinning stage. Longer and stable filament generation is detected as a discerning feature for non-Newtonian systems that appears more prominent with increasing dispersed phase shear-thinning properties. The results also indicate an inverse relation of droplet length with the continuous phase flow rate and xanthan gum concentration, while the droplet formation frequency and its polydispersity vary directly with those parameters.

Formulation and optimization of novel dexibuprofen- Aloe vera deformable emulgels for enhanced anti-inflammatory activity

Dexibuprofen (DIBU) has been used to treat inflammation and pain caused by a range of illnesses, including arthritis. Its efficacy, however, is substantially hampered by gastric and CNS effects on its oral administration. Hence, present study is working on development of a unique topical emulgel formulation that maximises its anti-inflammatory efficacy in order to avoid its oral dosing. To begin, DIBU formulation was optimised and incorporated into Aloe vera gel base to develop Dexibuprofen Aloe vera emulgel (DAE). Following that, the anti-inflammatory activity was investigated in Wister rats as an experimental animal. Light liquid paraffin (LLP), Span 20, and Tween 20 were used to produce DIBU emulsions. Using a statistical optimization technique, central composite design, the emulsion formulation was optimised for desirable globule size and zeta potential. The physico-chemical characterization studies showed that DAEs are transparent with good homogeneity and spreadability without phase separation. Rheological studies revealed that, DAEs are non-newtonian systems with shear thinning behaviour (viscosity 98768 ± 78 to 109574 ± 54 cP). They also demonstrated remarkable bio-adhesive strength (6.4 ± 1.2 to 6.8 ± 2.2 kg/cm2) without any signs of skin irritation. Drug diffusion follows zero order kinetics with non-fickain diffusion mechanism. The pharmacodynamic testing found that the optimised DAE2 reduced paw volume by 96.5 ± 3.4% and 94.18 ± 2.8% in carrageenan and egg albumin produced edoema techniques, respectively. The findings revealed that newly created DAEs can be used as prospective topical delivery systems for DIBU to augment its anti-inflammatory impact in lieu of oral tablets for the treatment of rheumatic illnesses such as arthritis.

The Influence of Tea Tree Oil on Antifungal Activity and Pharmaceutical Characteristics of Pluronic® F-127 Gel Formulations with Ketoconazole

Fungal skin infections are currently a major clinical problem due to their increased occurrence and drug resistance. The treatment of fungal skin infections is based on monotherapy or polytherapy using the synergy of the therapeutic substances. Tea tree oil (TTO) may be a valuable addition to the traditional antifungal drugs due to its antifungal and anti-inflammatory activity. Ketoconazole (KTZ) is an imidazole antifungal agent commonly used as a treatment for dermatological fungal infections. The use of hydrogels and organogel-based formulations has been increasing for the past few years, due to the easy method of preparation and long-term stability of the product. Therefore, the purpose of this study was to design and characterize different types of Pluronic® F-127 gel formulations containing KTZ and TTO as local delivery systems that can be applied in cases of skin fungal infections. The influence of TTO addition on the textural, rheological, and bioadhesive properties of the designed formulations was examined. Moreover, the in vitro release of KTZ, its permeation through artificial skin, and antifungal activity by the agar diffusion method were performed. It was found that obtained gel formulations were non-Newtonian systems, showing a shear-thinning behaviour and thixotropic properties with adequate textural features such as hardness, compressibility, and adhesiveness. Furthermore, the designed preparations with TTO were characterized by beneficial bioadhesive properties. The presence of TTO improved the penetration and retention of KTZ through the artificial skin membrane and this effect was particularly visible in hydrogel formulation. The developed gels containing TTO can be considered as favourable formulations in terms of drug release and antifungal activity.

Vibroextrusion flow of concrete mixtures in a right four-corner pyramidal channel

The purpose of the research was to obtain calculation formulas for describing the flow of concrete mixtures and determining their viscosity directly in the process of vibroextrusion in regular quadrangular pyramidal channels.
 In solving the flow problems, it was taken into account that concrete mixtures are non-Newtonian systems in the conditions of a vibration field, and hydrodynamic theories were used to calculate the processes and rheological characteristics.
 Since the calculation formulas for describing the flow of fluids in a regular quadrangular pyramidal channel are absent and the channel has a square cross section, an analytical dependence was used to characterize the process, which describes the flow of a Newtonian fluid in a rectangular channel of constant cross section. The authors proposed for use simplified formulas for determining the maximum flow rate and flow rate of a Newtonian fluid in a channel of rectangular cross-section.
 The degree of decrease in the flow velocity and the flow rates of a Newtonian fluid in a channel of rectangular cross-section in comparison with the flow between flat parallel plates are analyzed.
 To describe the flow of concrete mixtures in regular quadrangular pyramidal channels, the proposed coefficients for reducing the speed and flow rate, as well as the existing formulas for the flow between flat symmetric stationary walls, which converge, were used.
 The possibility of using the obtained formula for the flow rate in a regular quadrangular pyramidal channel for calculating the viscosity of a concrete mixture during vibration extrusion is shown. To simplify the experimental procedure, a new formula for calculating the viscosity based on the expiration time for a certain amount of concrete mixture has been proposed.
 The formulas obtained are convenient for further mathematical processing and have no restrictions in their application. The proposed method for determining the viscosity expands the possibilities of studying the rheological properties of concrete mixtures in the vibroextrusion of fiber-reinforced concrete mixtures.

Long-time instability and transient behavior of pressure-driven flow of a power-law fluid in a plane channel overlying a porous layer

The present study is undertaken to analyze the hydrodynamic stability of pressure-driven flow of non-Newtonian fluid-porous systems, where the fluid exhibits the power-law rheology. Such combined fluid-porous flow systems are widely prevalent in diverse geophysical and industrial applications. In the beginning, modal analysis has been performed for comprehending the long-time flow transition characteristics. The plots of the eigenfunctions corresponding to the critical eigenmodes demonstrate the intricate interplay between the non-Newtonian viscosity (quantified by the flow behavior index n) and the porous layer (quantified by depth ratio). It is observed that for a shear-thinning fluid, the flow transition is less sensitive to a variation in depth ratio than that for a shear-thickening fluid. In addition, by exploring the transient energy growth and pseudospectrum in the framework of non-modal stability analysis, the responses to initial conditions and external excitations have been investigated in detail.

Prediction of bed voidage in multi-phase fluidized bed using Air/Newtonian and non-Newtonian liquid systems

Prediction of bed voidage in multi-phase fluidized bed using Air/Newtonian and non-Newtonian liquid systems

Viscoelastic liquid bridge breakup and liquid transfer between two surfaces

We studied experimentally the breakup of liquid bridges made of aqueous solutions of Poly(acrylic acid) between two separating solid surfaces with freely moving contact lines. For polymer concentrations higher than a certain threshold (~30 ppm), the contact line on the surface with the highest receding contact angle fully retracts before the liquid bridge capillary breakup takes place at its neck. This means that all the liquid remains attached to the opposing surface when the surfaces are separated. This behavior occurs regardless of the range of liquid volume and stretching speed studied. Such behavior is very different from that observed for Newtonian liquids or non-Newtonian systems where contact lines are intentionally pinned. It is shown that this behavior stems from the competition between thinning of bridge neck (delayed by extensional thickening) and receding of contact line (enhanced by shear thinning) on the surface with lower receding contact angle. If the two surfaces exhibit the same wetting properties, the upper contact line fully retracts before the capillary breakup due to the asymmetry caused by gravity, and, therefore, all the liquid remains on the lower surface.