Dynamic Viscosity Research Articles

Impact of tiger nut milk as a substitute for cow milk on the rheological, physiochemical, and organoleptic properties of functional ice cream

AbstractTiger nuts are an excellent food choice due to their rich mineral, fiber, and antioxidant content. Tiger nut milk was replaced by 25, 50, 75, and 100% of cow’s milk in the ice cream mixture. The impact of substituting cow milk with tiger nut milk on the physicochemical, rheological, and organoleptic properties of ice cream was examined. Adding tiger nut milk in a combination resulted ice cream mixes with more fiber and antioxidants and a lower protein and ash levels compared to the control (100% cow milk). Ice cream with tiger nut milk was higher in Fe and Zn than that of control. Dynamic viscosity values of ice cream mixes with tiger nut milk were decreased with increasing values of the applied shear rate compared to the control. All functional ice cream formulations with tiger nut milk showed higher specific gravity and melting rate with lower overrun percentages than the control. Regarding taste and flavor, structure, texture, and melting in the mouth, there is no appreciable difference between the T25, T50, and control treatments. Therefore, cow’s milk can be replaced with tiger nut milk up to 50% in the ice cream industry to raise the nutritional value and functional properties.

REDUCING THE VISCOSITY OF THE OIL MIXTURE BY A ROTARY PULSE APPARATUS IN UKHTA — YAROSLAVL OIL PIPELINE

Physical methods of exposure can be used to improve the rheological characteristics of viscous, resinous oils, the transportation of which through main pipelines requires additional operating costs. The authors of this article evaluated the effectiveness of the method for improving oil rheology due to multifactorial effects (shear loads, high–amplitude pressure pulses, developed turbulence) on a sample of a mixture of oils of the Ukhta - Yaroslavl oil pipeline in a rotary pulse apparatus (RIA). The specific power consumption for processing an oil sample was 2.84 kWh/m3. The initial rheological and physico-chemical parameters of the studied oil are described, according to which it is characterized as heavy, viscous, highly resinous oil. The analysis of the flow curves showed that, by the nature of the flow, the sample of a mixture of oils from the Ukhta — Yaroslavl main oil pipeline belongs to Newtonian liquids. The evaluation of the effectiveness of the multifactorial effect on the oil sample implemented in RIA was carried out using dimensionless coefficients showing the ratio of dynamic viscosity, the specific power required to maintain the flow of oil in a rotary viscometer before and after physical exposure to oil, as well as the ratio of the change in the energy of thixotropy of oil to the energy spent on the processing process. The samples were processed in an RIA-based installation, in which pressure pulsations, developed turbulence, and large shear loads are generated in the liquid flow. When comparing the viscosity values of untreated and treated mixed oil in a rotary pulse apparatus, the dynamic viscosity measured at 20 °C decreased by 8 %. The component composition of the oil after processing in RIA has practically not changed. Measuring the viscosity of oil before processing and immediately after processing in RIA shows a decrease in viscosity by more than two times, since the temperature of the oil flow increases after passing through RIA by more than 10 °C. The increase in oil temperature during processing is due to large shear stresses during its flow in slit channels and in the gap between the rotor and stator due to the large amplitude of pressure pulsations and flow velocity.The relaxation time of the rheological parameters of the treated oil was seven days.

A Review on Nanofluids: Preparation, Stability Mechanisms, and Applications of Ethylene Glycol – Water Based Nanofluids Dispersed with Multi Walled Carbon Nanotubes

The current study examines the thermal conductivity and dynamic viscosity of ethylene glycol– water solutions comprising oxidized multiwalled carbon nanotubes. Nanofluids, the fluid suspensions of nanomaterials, have shown many interesting properties, and the distinctive features offer unprecedented potential for many applications. This paper summarizes the recent progress on the study of nanofluids, such as the preparation methods, the evaluation methods for the stability of nanofluids, and the ways to enhance the stability for nanofluids, the stability mechanisms of nanofluids, and presents the broad range of current and future applications in various fields including energy and mechanical and biomedical fields. At last, the paper identifies the opportunities for future research.

Development of Chitosan-Coated Electrospun Poly(3-hydroxybutyrate) Biohybrid Materials for Growth and Long-Term Storage of Bacillus subtilis

Numerous bacterial species can both suppress plant pathogens and promote plant growth. By combining these bacteria with stabilizing substances, we can develop biological products with an extended shelf life, contributing to sustainable agriculture. Bacillus subtilis is one such bacterial species, possessing traits that enhance plant growth and offer effective protection, making it suitable for various applications. In this study, we successfully incorporated B. subtilis into hybrid materials composed of poly(3-hydroxybutyrate) (PHB) fibers coated with chitosan film. The polymer carrier not only supports the normal growth of the bioagent but also preserves its viability during long-term storage. For that reason, the impact of chitosan molecular weight on the dynamic viscosity of the solutions used for film formation, as well as the resulting film’s morphology, mechanical properties, and quantity of incorporated B. subtilis, along with their growth dynamics was investigated. SEM was used to examine the morphology of B. subtilis, electrospun PHB, and PHB mats coated with chitosan/B. subtilis. The results from mechanical tests demonstrate that chitosan film formation enhanced the tensile strength of the tested materials. Microbiological tests confirmed that the bacteria incorporated into the hybrid materials grow normally. The conducted viability tests demonstrate that the bacteria incorporated within the electrospun materials remained viable both after incorporation and following 90 days of storage. Moreover, the prepared biohybrid materials effectively inhibited the growth of the plant pathogenic strain Alternaria. Thus, the study provides more efficient and sustainable agricultural solutions by reducing reliance on synthetic materials and enhancing environmental compatibility through the development of advanced biomaterials capable of delivering active biocontrol agents.

Experimental investigation of dynamic viscosity of water-based nanofluids containing tungsten oxide–multi-walled carbon nanotubes–zirconium oxide nanoparticles at mono and hybrid conditions

Experimental investigation of dynamic viscosity of water-based nanofluids containing tungsten oxide–multi-walled carbon nanotubes–zirconium oxide nanoparticles at mono and hybrid conditions

Turbulent convection in emulsions: the Rayleigh–Bénard configuration

This study explores heat and turbulent modulation in three-dimensional multiphase Rayleigh–Bénard convection using direct numerical simulations. Two immiscible fluids with identical reference density undergo systematic variations in dispersed-phase volume fractions, $0.0 \leq \varPhi \leq 0.5$ , and ratios of dynamic viscosity, $\lambda _{\mu }$ , and thermal diffusivity, $\lambda _{\alpha }$ , within the range $[0.1\unicode{x2013}10]$ . The Rayleigh, Prandtl, Weber and Froude numbers are held constant at $10^8$ , $4$ , $6000$ and $1$ , respectively. Initially, when both fluids share the same properties, a 10 % Nusselt number increase is observed at the highest volume fractions. In this case, despite a reduction in turbulent kinetic energy, droplets enhance energy transfer to smaller scales, smaller than those of single-phase flow, promoting local mixing. By varying viscosity ratios, while maintaining a constant Rayleigh number based on the average mixture properties, the global heat transfer rises by approximately 25 % at $\varPhi =0.2$ and $\lambda _{\mu }=10$ . This is attributed to increased small-scale mixing and turbulence in the less viscous carrier phase. In addition, a dispersed phase with higher thermal diffusivity results in a 50 % reduction in the Nusselt number compared with the single-phase counterpart, owing to faster heat conduction and reduced droplet presence near walls. The study also addresses droplet-size distributions, confirming two distinct ranges dominated by coalescence and breakup with different scaling laws.

Impact of statistical poly(propylene co-ethylene) on the thermo-mechanical properties of high-density polyethylene

A series of high-density polyethylene and a statistical copolymer of poly(propylene-co-ethylene) blends in a wide range, namely (0, 10, 20, 30, 40, 50, 60,70, 80, 90, 100) abbreviated as HDPE/VM were systematically investigated by using a rheometer, differential scanning calorimetry (DSC) measurements, polarized optical microscopy (POM) and tensile tests. Rheometer results show that adding VM decreases dynamic viscosity, storage, and loss modulus. Han plot shows that HDPE and VM are compatible and miscible in the range from 20 to 60 VM % in the molten state. DSC results show little nucleation effect of VM on HDPE (HDPE’s melt crystallization temperature shifts 2 °C higher). Moreover, a linear composition dependence of ∆cp ∆Hc, ∆Hm shows that PE and VM are most probably compatible in the molten state in composition range from 20 to 60%. However, upon crystallization, the VM and PE domains occur distinctively. The results of the tensile tests demonstrated a decrease in elastic modulus, yield stress, and ultimate tensile strength as VM content increased. At low VM content (less than 20%), high elongation at break was detected for the blends, and very fine spherulites of HDPE were found across the sample by POM.

Transfer learning for accurate description of atomic transport in Al-Cu melts.

Machine learning interatomic potentials (MLIPs) provide an optimal balance between accuracy and computational efficiency and allow studying problems that are hardly solvable by traditional methods. For metallic alloys, MLIPs are typically developed based on density functional theory with generalized gradient approximation (GGA) for the exchange-correlation functional. However, recent studies have shown that this standard protocol can be inaccurate for calculating the transport properties or phase diagrams of some metallic alloys. Thus, optimization of the choice of exchange-correlation functional and specific calculation parameters is needed. In this study, we address this issue for Al-Cu alloys, in which standard Perdew-Burke-Ernzerhof (PBE)-based MLIPs cannot accurately calculate the viscosity and melting temperatures at Cu-rich compositions. We have built MLIPs based on different exchange-correlation functionals, including meta-GGA, using a transfer learning strategy, which allows us to reduce the amount of training data by an order of magnitude compared to a standard approach. We show that r2SCAN- and PBEsol-based MLIPs provide much better accuracy in describing thermodynamic and transport properties of Al-Cu alloys. In particular, r2SCAN-based deep machine learning potential allows us to quantitatively reproduce the concentration dependence of dynamic viscosity. Our findings contribute to the development of MLIPs that provide quantum chemical accuracy, which is one of the most challenging problems in modern computational materials science.

Self-sustained chaotic movement of electrothermal responsive liquid crystal elastomer pendulum

Self-sustained movement has the ability to absorb energy from the external environment to maintain its own movement. In the present work, a self-sustained chaotic simple pendulum system featuring an electrothermal responsive liquid crystal elastomers fiber and a mass ball is proposed and examined. The power-on state is achieved in the system through the infusion of liquid metal into this fiber. Which enables the fiber to shrink, feeding energy into the system to compensate for the energy dissipation resulting from damping, thus allowing the system to maintain its self-sustained movement. On the basis of the existing dynamic liquid crystal elastomer model, the dynamic governing equations are established, and the movement behavior of the system under electrothermal stimulation is theoretically explored. Numerical findings suggest that the simple pendulum system presents three different movement patterns, namely stationary pattern, self-sustained oscillatory pattern, and self-sustained chaotic pattern. Moreover, five system parameters of elastic coefficient, viscosity coefficient, gravitational acceleration, shrinkage coefficient and electrothermal strength are examined. The present work can contribute to a better understanding of self-sustained chaotic systems driven by electrothermal responsive materials and offer guidance for further exploration of applications such as chaos machine, and mind-brain chaos analysis.

Analysis of shear creep damage model of slope rock mass under the influence of coupled damage effects (DBSM)

Abstract This article reveals the evolution law of shear creep damage of carbonaceous shale (weak interlayer of slope) under dynamic load from a mechanical perspective by combining indoor experiments and theoretical research. Firstly, a coupled damage variable D BSM was established for the initial damage D 0 and dynamic disturbance shear creep damage D BS of rock mass based on the theory of damage mechanics. Secondly, according to the fractional calculus operator theory and considering the influence of coupled damage variable D BSM on the viscosity coefficient of rock mass in the viscoelasticity and viscoplasticity creep stages, a shear creep damage model of rock mass was established. At the same time, combined with the shear creep test data under the influence of dynamic loads, the damage evolution law of shear creep in carbonaceous shale (weak interlayer of slope) was revealed, and the accuracy of the established shear creep damage model was verified. Finally, the damage evolution law of carbonaceous shale was quantitatively analyzed. Results show that: The shear creep damage model established in this article has unique advantages. The greater the initial damage, the more likely shear creep failure is to occur under the influence of dynamic disturbance and shear creep loads. Dynamic disturbance accelerates the damage of weak interlayers of slope. The cumulative coupling damage of carbonaceous shale (D ma ≤0.18) under dynamic disturbance and multi-stage shear creep loads exhibits an S-like evolution pattern. The shear creep damage mechanism of carbonaceous shale is characterized by obvious initial damage effect, dynamic disturbance damage effect, and stress response characteristics.

Effect of soft magnetic particles content on multi-physics field of magnetorheological composite gel clutch with complex flow channel excited by Halbach array arrangement

In this paper we investigate the influence of soft magnetic particle mass fraction on the multi-physics field of proposed magnetorheological (MR) gel clutch. A novel MR gel clutch with complex cup-shaped gap is described, whose performance is based on the relative placement between Halbach array arrangement and MR gel. Smart MR gel with 40 wt%, 50 wt%, 60 wt%, 70 wt% and 80 wt% of soft magnetic particles used as the transfer medium and Halbach array is adopted as magnetic excitation system. Its magnetic/mechanical analysis is carried out based on Bingham-plastics model using COMSOL Multiphysics software, which takes into account the variation of dynamic viscosity with magnetic flux density. The distribution of the magnetic flux density, shear yield stress, post-yield viscosity, shear stress and torque in the four flow channels during the transition from engagement state to disengagement state are obtained and analyzed in detail. Multi-physics field characteristics of proposed MR gel clutch with five kinds of MR gels are studied and compared in order to give some useful suggestions in the design phase. Finally, the dynamic torque of the MR clutch with different MR gel is experimentally evaluated.

Experimental determination of the coefficient of viscosity of the dry snow

Snow compaction is a natural process in the evolution of any snow cover, and this obviously changes the physical and mechanical properties of a snow thickness. The quantitative estimate of this process is a coefficient of the snow viscosity, which is linearly related to the rate of the snow cover deformation The technique for preparation and testing of samples with the fine-grain snow under condition of uniaxial compression at negative temperatures is described. It was determined that values of the snow viscosity coefficient fall within the range from 0.10 to 0.30 g/cm³ for three temperature intervals. The viscosity coefficient of the fine-grain snow varies from 10⁸ до 10¹⁰ Па. The data obtained made possible to find the limits of variability of this coefficient for winter conditions on the Russian plain. A dependence of the viscosity coefficient on the snow density and temperature is proposed, and it describes the series of the above shown experimental data. It is shown that influence of changes in the viscosity coefficient of fine-grain snow on the snow properties depending on its density are comparable in scale to the influence of the temperature. The result may be useful for modeling the evolution of snow cover.

Application of the significant structure theory for the viscosity modeling of ionic fluids

The present work introduces the application of a modified significant structure theory (SST) in order to obtain improved representations of the dynamic viscosity of several representative last-generation ionic fluids: pure ionic liquids (ILs) and deep eutectic solvents (DESs). The activated-state variables present in the resulting SST-based model were related to well-known thermodynamic potentials (residual internal energy, liquid and solid molar volumes) which in turn were estimated from two simple cubic equations of state of the van der Waals type: Soave-Redlich-Kwong or Peng-Robinson. The modifications introduced to the SST approach were successfully verified during the correlation and prediction of experimental dynamic viscosities of 3 families of imidazolium-based ILs ([CXmim][BF4], [CXmim][PF6] and [CXmim][Tf2N]), one pyridinium-based IL ([b3mpy][BF4]), one pyrrolidinium-based IL ([P14][Tf2N]), one ammonium-based IL ([N1114][Tf2N]) and four ILs having nonfluorinated anions ([dmim][MeSO4], [bmim][EtSO4], [bmim][Ac] and [b3mpy][dca]) over a temperature range varying from 273.15 to 438.15 K and at pressures from 1 to 3,000 bar We also considered three archetypal choline chloride-based DESs for model validation: Reline, Ethaline and Glyceline within a temperature range varying from 293.15 to 373.15 K and at pressures from 1 to 1,000 bar

Study on the Flow Characteristics of Non-Newtonian Drilling Fluid Through Vibrating Screen Meshes

Summary Composite screens are a critical component of drilling fluid shale shakers, and their performance directly affects the recovery efficiency of drilling fluid. This study focuses on the composite screens of shale shakers and simulates the flow of non-Newtonian drilling fluids through different structures of composite screens to investigate the impact of drilling fluid rheological parameters and screen compositions on screening performance. The research results indicate that the flow velocity of the drilling fluid is the highest while passing through the lower screen, and the turbulent kinetic energy (TKE) is at its maximum in the lower screen area, where energy dissipation is also the greatest. An increase in the rheological parameters of the four-parameter model drilling fluid generally increases the difficulty of passing through the screen, with the flow behavior index and viscosity coefficient having a particularly significant impact on the pressure drop coefficient. Compared with the plain composite screen, the herringbone composite screen and plain patterned composite screen have lower pressure drop coefficients, with the herringbone composite screen demonstrating the best screening performance. These findings provide theoretical references for flow analysis and structural optimization of shale shaker screens in drilling fluid applications.

Molecular model and its evolution during secondary regeneration of asphalt based on molecular dynamics

With the use of recycled asphalt pavement, numerous recycled pavements will suffer from damages which needs to be regenerated for the second time (i.e. secondary regeneration). The mechanism and impact of secondary regeneration may diverge from those observed during primary regeneration. To study the aging and regeneration mechanism of secondary regenerated asphalt, the molecule models of regenerant and asphalts under different aging states were established through the molecular dynamics (MD). The double-layer diffusion models were constructed to examine the fusion behavior of new and aged asphalts. Based on this, the dynamic viscosity, rotational viscosity, bulk modulus, and shear modulus of secondary regenerated asphalt were predicted. The findings indicate that the established molecular models have a strong correlation with real asphalt molecules. During secondary regeneration, the deepening of asphalt aging reduces the fusion velocity and efficiency between aged and new asphalts. The introduction of regenerant can enhance the diffusion velocity between the aged and new asphalts, yet it does not necessarily improve their fusion degree. During the process of secondary regeneration, the shear modulus of secondary aged asphalt can be effectively restored by adding regenerant, but the recovery of dynamic viscosity, rotational viscosity and bulk modulus presents poor trends when compared to the primary regeneration.

Experimental study on natural convection heat transfer performance of microencapsulated phase change material slurry in a square cavity

Microencapsulated phase change slurry (MicroEPCMS), consisting of microencapsulated phase change material (MicroEPCM) and base liquid, represents a novel latent heat functional fluid that can absorb a large amount of heat within its phase change temperature range. It has found widespread use as a functional liquid cooling medium for heat dissipation in batteries, electronic devices, and other devices. In this work, MicroEPCMS with different MicroEPCM concentration were prepared. The physical properties of MicroEPCMS including density, thermal conductivity, and dynamic viscosity were tested within different temperature ranges. The results showed that the MicroEPCMS exhibits a superior thermal energy storage capacity compared to water. In the phase change range of MicroEPCM, the MicroEPCMS has a higher thermal conductivity compared to water. In addition, the natural convection heat transfer characteristics of MicroEPCMS in a square cavity were investigated under varying heating power. The results indicated that MicroEPCMS can enhance natural convection heat transfer by absorbing heat with a minimal temperature rise during the phase change process compared to water. Moreover, higher heating power enables natural convection enhancement of MicroEPCMS in a square cavity. These results underscore the significant potential of MicroEPCMS as a functional liquid cooling medium for applications in thermal energy storage and thermal management.

Comparative study on the performance of fresh concrete comprising manufactured sand vs. river sand during full-scale long-distance pumping

The shift from river sand (RS) to manufactured sand (MS) as a fine aggregate in concrete is driven by environmental sustainability concerns. However, negative impacts of MS on concrete workability have raised doubts about its suitability for long-distance pumping in construction projects. This study evaluates the performance of MS concrete compared to RS concrete of the same strength grade during long-distance pumping. A full-scale coiled pipeline with measured length of 348 m was built, twelve batches of C30 and C60 concrete were prepared, and pumping tests were conducted at discharge rates of 2.5–18.9 liter per second (L/s). The workability and rheological parameters were assessed before and after pumping. The measured and predicted pumping pressure were analyzed and calculated based on rheological parameters and lubricating layer (LL) parameters. Results indicate that MS increased the yield stress and decreased the LL thickness index of C30 concrete, while it decreased the viscosity coefficient of C60 concrete. Post-pumping, the change in yield stress was similar for both MS and RS concrete, but MS reduced the plastic viscosity change in C60 concrete. MS did not significantly affect the pumping pressure loss, but influenced the pumping pressure prediction deviation by influencing the thixotropy. The classic pumping pressure prediction model developed by Kapan obviously overestimated the pumping pressure during long-distance pumping, and the deviation was more prominent in high-strength concrete pumping. MS increased the thixotropy of C30 concrete and reduced the prediction deviation of pumping pressure, but had the opposite effect on C60 concrete.

Flow of ferrofluid within a channel driven by a rotating magnetic field: Implications of surface magnetic stresses and magnetic body couples

This research presents a discussion of the flow of a ferrofluid in a square cross-sectional area channel driven by a rotating magnetic field. The objective was to evaluate the coupled effect of surface magnetic stresses and diffusion of the internal angular momentum as potential mechanisms for generating flow. In many analyses of flow induced by time-dependent magnetic fields, the effect of the diffusion of the internal angular momentum has been dismissed, based on the negligible value of the spin viscosity coefficient estimated from order-of-magnitude analyses. In light of these considerations, we conducted a review of the existing analyses and put forward a new approach of the order-of-magnitude analysis of the spin viscosity coefficient. The paper presents a detailed description of the solution procedure for the flow field, with and without the inclusion of the diffusion of the internal angular momentum. To justify the assumptions involved in the analytical solution of the flow, we expanded a previous scale analysis to define Reynolds and Strouhal numbers in the linear and internal angular momentum balance equations. It was proven that the maximum surface velocity predicted at the ferrofluid–air boundary closely aligns with the reported experimental data for moderate amplitudes of the magnetic field.

Numerical fluid structure simulation analysis of temperature-dependent dynamic viscosity with a simplified deep drilling model

ABSTRACT This paper simulates the temperature-dependent dynamic viscosity of the cutting fluid’s flow, thus analysing the approximated real behaviour in a simplified model. In order to take the heat transfer between the workpiece and the cutting fluid into account, the Finite Element Method (FEM) was bidirectionally coupled. A mathematical formula for determining the dynamic viscosity of the cutting fluid as a function of temperature was used for the temperature evolution. Simulations were performed using the standard k-ω-SST, k-ω-SST-SAS, and k-ω-SST-DES turbulence models for comparison. The results show that the influence of dynamic viscosity and temperature plays an important role and should therefore not be neglected in process simulations. For example, increasing the temperature from T = 25 °C to T = 150 °C reduced viscosity by 95%. The modelling approach presented here is suitable for future analysis simulations and can be applied not only to different drill geometries but also to numerous machining processes where dynamic viscosity plays an important role.

Numerical Investigation on Photovoltaic Thermal Panel Using Various Nanofluids Concentrations

Increasing the efficiency of solar panels is crucial for effective use of renewables. The present numerical study deals with improving the performance of a PVT system with nanofluid using CFD FLUENT software. ZnO-water and SiO2-water nanofluids are investigated and correlation are established between the PVT efficiency and various nanofluid volumetric concentrations ranging from 1% to 10%. Validation of the present results is verified by comparison with experimental data. Comprehensive research is conducted to evaluate the correlation between the thermophysical properties of nanofluids such as density, thermal conductivity, specific heat capacity and dynamic viscosity. The results demonstrate that the overall efficiency of the ZnO-water nanofluid and -water nanofluid increases by 0.44% and 0.24%, respectively, as the volumetric concentration of the nanofluid rises from 1% to 10%. The ZnO-water nanofluid reveals enhanced thermal and electrical efficiency compared to the -water nanofluid due to its superior thermal conductivity and enhanced heat transfer capabilities along the absorber tube. The ZnO-water nanofluid exhibits a greater heat transfer coefficient, thereby facilitating the cooling mechanism of the PV panel and reducing the PV cell temperature, hence enhancing power generation.