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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. [ABSTRACT FROM AUTHOR]

Paracetamol (PC), the active ingredient in Efferalgan, is an effervescent tablet medicine used in the treatment of mild-to-moderate pain. Chitosan (CH) is a biopolymer having immense structural possibilities for chemical and mechanical modifications to generate novel properties, functions and applications, especially in the pharmaceutical area. The dynamic viscosities, η, have been measured, and investigated for the mixture of CH in acidic water and paracetamol aqueous solutions over the entire range of the temperature 20–65°C, and concentrations of 1–10 g/l. The main objective of our research described here was to determine the viscometric properties of biopolymer solutions of CH in PC, as a function of the volume fraction fCH in the CH and PC mixture and temperatures. We identified three main concentration regimes, corresponding to a dilute regime, a critical regime and the semi-dilute regime. Our results showed that the CH/PC is a promising mixture for use in pharmaceutical and antibacterial applications. The chitosan shows antimicrobial activity against various microorganisms, including bacteria. [ABSTRACT FROM AUTHOR]

Objective: The interaction of the eutectic plasticizer—aqua complex "glycerin–water" with sawdust of larch wood of two fractional compositions was studied: a fine fraction (wood flour) and a coarse fraction (sawdust) with a particle size of 1−3 mm. Methods: The methods of optical microscopy were used to study the surface properties of samples, to measure the dynamic viscosity of spent solutions on a Brookfield viscometer; to measure the VGS retention index, a modified Jaime water retention technique was used. The obtained data are compared with the results of previous studies, in which it was shown that arabinogalactan (AG) performs the functions of a eutectic plasticizer in the structure of larch wood and is in the form of an aqua complex «AG–water». Results and Discussion: It was found that the amount of the attached aqua-complex—"glycerin−water" to the samples of larch sawdust corresponds to the amount of AG previously extracted from sawdust. The process of replacing the aqua-complex "AG−water" with the aqua-complex "glycerin–water" is analyzed on the diagram of relaxation states "two polymers–solvent." The experimental results are interpreted on the basis of previously obtained data on the effect of water and glycerin on the relaxation state of polymer components of wood. Conclusions: The fundamental difference between the two eutectic plasticizers is demonstrated: if, when drying larch wood, the destruction of the aqua-complex "AG−water" leads to the transfer of polymer components of wood from a highly elastic to a glassy state, then when using the aqua-complex "glycerin−water" (VGS), water is removed during drying, and the remaining glycerin ensures the preservation of polymer components of wood in a highly elastic state. The possible technological aspects of the revealed patterns are considered. [ABSTRACT FROM AUTHOR]

This document explores the impact of wind on the shape of shoaling and overturning waves using a two-phase DNS model, focusing on the wind Reynolds number (Re ∗) and its effects on wave shape. The simulations reveal that wind influences wave faces' steepness and geometrical parameters of overturning waves, with pressure and viscous stresses playing a role at the air-water interface. The findings suggest that wind significantly affects wave shape and overturning dynamics, potentially impacting coastal engineering and morphological evolution. The research compiled in this document provides valuable insights into fluid mechanics, surf zone dynamics, wind wave growth, and numerical modeling of wind effects on breaking waves, published in reputable journals. [Extracted from the article]

The article explores the linear stability analysis of a liquid film over a moving substrate, emphasizing the impact of varying film thickness and liquid properties on instability mechanisms. The study reveals that stabilizing mechanisms are influenced by the balance of forces, with surface tension effects diminishing as Kapitza numbers decrease. Results show that as the Kapitza number decreases, the maximum growth rate increases, with different liquids exhibiting varying growth rates and phase speeds of unstable perturbations. The study also delves into absolute and convective instabilities, providing insights into the stability of liquid films in industrial processes and potential applications in optimal control strategies. [Extracted from the article]

The article explores the use of harmonic resolvent analysis to study compressible cavity flows, emphasizing cross-frequency interactions. By applying this framework to linearized Navier-Stokes equations, the study uncovers the dominance of nonlinear cross-frequency interactions in perturbation amplification at different Mach numbers. The research validates the approach through low-Mach-number flow past an airfoil and extends its application to compressible cavity flows at Mach numbers of 0.6 and 0.8. The document also includes a collection of research articles on fluid mechanics, stability analysis, and flow control, offering valuable insights into fluid dynamics and control mechanisms. [Extracted from the article]

The article delves into the phenomenon of delayed gravitational collapse in colloidal suspensions, specifically focusing on the resistance of colloidal gels to gravity. Through theoretical modeling, the study examines the delay time, which determines the shelf life of gel-based products, and sedimentation behavior. Factors such as initial volume fraction and particle interactions play a crucial role in understanding the collapse behavior of colloidal gels under gravitational forces. The research sheds light on the time evolution of sedimenting gels, density profiles, colloidal flux, and volume fractions, revealing distinct regimes of delay, linear settling, and exponential compaction. The study underscores the significance of dilatational viscosity and local density variations in comprehending the dynamics of colloidal gels under gravity, suggesting potential modifications to the model for better alignment with experimental findings and advocating for further research to incorporate erosion mechanisms and higher dimensions for a more holistic understanding of colloidal gel behavior. [Extracted from the article]

Introduction: Planetary-face gears combine the advantages of both planetary and face gears, offering potential value for wind power applications. During the gear meshing process, a large amount of heat is generated, and tooth wear also occurs, which affects transmission performance. Methods: Analyzing multiple factors such as lubrication performance and thermal effects of meshing pairs plays a crucial role in improving the overall lifespan of transmission systems. This study developed a nonlinear dynamic model of a wind power planetary-face gear system, considering factors like random wind load, tooth surface friction, temperature rise, tooth side clearance, and elastic lubrication. Nonlinear methods such as bifurcation diagram, maximum Lyapunov exponent diagram, and time-frequency diagram were used to analyze the effects of wind turbine radius, average wind load, temperature rise, and lubricant viscosity on the dynamic response of the gear transmission system under random wind loads. Results: The results show that selecting an appropriate wind turbine radius for different wind loads is essential to enhance system stability. Higher lubricant viscosity can suppress chaotic phenomena in gear systems. For a well lubricated gear system, tooth surface temperature rise is a key factor affecting the dynamic characteristics of the system. Discussion: This article aims to provide valuable insights into improving the operational stability of the wind turbine planetary gear system. [ABSTRACT FROM AUTHOR]

A project for the development of oil and gas fields, which provides for several systems, including a system for collecting, preparing, and transporting natural and associated petroleum gas through field gas pipelines, is discussed. The main results of the scientific approach to the influence of gas-dynamic forces on the characteristics of a field gas pipeline are presented. The influence of the physical, chemical, thermodynamic, and technological parameters of natural or associated petroleum gas during its movement on the properties of the gas and the characteristics of the field gas pipeline is also considered. [ABSTRACT FROM AUTHOR]

Simple Summary: A significant problem is the increasing incidence of tick-borne diseases. Ticks can be found in green areas, such as parks and clearings where trees, bushes, or tall grass grow. Humans and animals can become infected with various diseases through ticks, e.g., Lyme disease, tick-borne encephalitis, babesiosis, and anaplasmosis. An important aspect of preventing tick-borne diseases is the use of repellents to limit contact between ticks and humans and animals. Our research team has developed preparations based on natural raw materials with the addition of essential oils that act as a repellent against ticks. In addition to their pleasant scent, our preparations are environmentally friendly because they consist of natural ingredients. Background: Ticks (Acari: Ixodida) pose a serious medical and veterinary threat as vectors of tick-borne pathogens. The wide variety of tick repellents available on the market primarily consist of synthetic preparations that may disrupt the ecological balance and accumulate in the environment, leading to harmful effects on humans and animals. The aim of the study was to develop an ecological preparation based on natural raw materials (biopolymers) with the addition of a mixture of essential oils that act as tick repellents. Methods: The preparations were acquired through the emulsification method, specifically the oil-in-water emulsion technique. The assessment encompassed an analysis of their physicochemical properties, including centrifugal and thermal stability, dynamic viscosity, wetting angle, and conductivity. Additionally, their biodegradation and ecotoxicity profiles were evaluated, as well as their impact on tick behavior. Results: The preparations exhibited stability, rapid biodegradation, and absence of ecotoxicity. Additionally, they had repellent properties against the two tested species of ticks (Ixodes ricinus and Dermacentor reticulatus). Conclusions: Emulsion formulations comprising natural ingredients have significant research potential for combating ticks, thus mitigating the risk of tick-borne diseases in both human and animal populations. [ABSTRACT FROM AUTHOR]

In the present paper, we report data on the influence of choice of dispersion medium-precipitating agent pair on sol–gel process for lead zirconate-titanate ceramic precursor manufacturing. Acetic acid and 2-methoxyethanol were studied as dispersion media, whereas ethylene glycol and water as respective precipitating agents. Changes in optical, rheological properties and particle size distributions during the sol–gel transition were studied at different concentrations of precipitating agents. It was shown that the nature and relative concentration of dispersion medium and precipitating agent provide wide-range control of lead zirconate-titanate sol and gel properties as well as the rate of sol–gel process, mechanism of formation and structure of the gels. [ABSTRACT FROM AUTHOR]

The current study systematically explores the potential of nanofluids (NFs) as dielectric media in EDM to enhance the surface integrity of Inconel 825. To achieve this objective, applying nanofluids involves ensuring uniform dispersion of nanoparticles, specifically emphasising efficient heat dissipation, thereby aligning EDM processes. This investigation focuses on utilising MWCNTs NFs, graphene NFs, and hybrid NFs (maintaining a 1:1 ratio of nanoparticles) with a hydrocarbon-based EDM oil as the base fluid. This study marks a pioneering attempt to implement these NFs in the EDM process for Inconel 825. Comprehensive characterizations of NFs have been conducted before their application in the EDM process. These have included assessments of hydrodynamic diameter, zeta potential, dynamic viscosity, thermal conductivity, and breakdown voltage. A comparative analysis has been performed between the outcomes of NFs-based EDM and conventional EDM (using EDM oil). The results show that using graphene NFs, followed by MWCNTs NFs and hybrid NFs, improves thermal conductivity and stability during the EDM process. This results in an enhanced material removal rate and better surface roughness. In-depth examinations of surface irregularities, surface microcracks, recast layer thickness, and grain orientation are carried out using scanning electron microscopy and electron backscattered diffraction. Moreover, residual stress and microhardness are systematically determined to gain further insights into surface integrity. The results indicate that the comparatively higher dispersion of graphene within base dielectric fluid provided better surface integrity for ED-machined parts. [Display omitted] • The current study systematically explores the potential of NFs as dielectric media in EDM to enhance IN825 surface integrity. • This work focuses on utilising MWCNTs NFs, graphene NFs, and hybrid NFs with a hydrocarbon-based EDM oil as the base fluid. • Comprehensive characterisations of NFs have been conducted, encompassing hydrodynamic diameter, zeta potential, etc. • In-depth examinations of surface microcracks, recast layer thickness, and grain orientation are carried out through.·Moreover, residual stress and microhardness are systematically determined to gain further insights into surface integrity. [ABSTRACT FROM AUTHOR]

According to review of the literature, the influence of nanoparticle diameter with irregular shapes on viscosity requires further research since there is no relation between particle size and nanofluid stability. In this study, SiO2/EG–water-based nanofluid samples were prepared, and their viscosities were experimentally determined. SiO2 nanoparticles had sizes of 7, 15, and 40 nm, and the base fluid was a 50% ethylene glycol and 50% water mixture. Nanofluid samples were prepared using a two-step technique. Viscosity change was measured every 10 °C from 20 to 60 °C. The maximum viscosity values were observed for 7, 15, and 40 nm particles over an entire concentration range. Considering all measurements, the highest viscosity increase was 60.51% for 3% SiO2 (7 nm) at 60 °C, and the lowest viscosity change was 7.72% for 1% SiO2 (40 nm) at 40 °C. The most stable sample of the current study was 1% SiO2 (15 nm), and its Zeta potential was − 35.6 mV. Finally, a new empirical equation that included temperature, particle diameter, and concentration terms is suggested to predict dynamic viscosity, with Radj2 = 0.98. It was also compared with previous correlations. [ABSTRACT FROM AUTHOR]

Copyright of Lubrication Engineering (0254-0150) is the property of Editorial Office of LUBRICATION ENGINEERING and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Automobile Technology & Material is the property of Automobile Technology & Material Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The document presents research articles on numerical simulations of Rayleigh-Taylor instability, focusing on mixing layer width and flow statistics. The simulations are validated against experimental data, showing good agreement and successful validation of the numerical model. The studies also explore the impact of turbulence on reaction rates in complex mixtures, providing insights into the behavior of mixing processes in turbulent flows. The articles cover various aspects of fluid mechanics, plasma reactions, turbulence, and mixing phenomena, offering valuable insights into these complex physical phenomena from diverse perspectives. [Extracted from the article]

The article "Cavitation dynamics in creeping flow" delves into the study of cavitation in water between a spherical surface and a flat substrate, using Newton ring positions and high-speed cameras to track bubble evolution. The research reveals a scaling law for creeping flow cavitation bubbles, where bubble area and lifetime are inversely related, distinguishing them from inertial dynamics. The implications of cavitation in various applications, such as joint cracking sounds and lubricant wear, are also discussed. The document contains a collection of research articles covering molecular mechanisms, bubble dynamics near solid surfaces, and damage in soft materials caused by cavitation-induced forces, offering a comprehensive exploration of cavitation phenomena. [Extracted from the article]

Highlights Ultra‐high molecular weight polyethylene (UHMWPE) is commonly used with many layers to realize protection and this can greatly benefit from advancements in fabric mechanical properties. This research introduces an innovative approach to crafting a composite felt, leveraging UHMWPE fabric, carbon nanotubes (CNTs), shear thickening fluid (STF), and polyvinyl alcohol (PVA) binder through a spray technique. The method results in a fabric with exceptional tensile strength and anti‐impact characteristics. Observations during the fabrication process reveal profound surface morphology alterations, showcasing an intricate layering of PVA binder, CNTs, and STF that seamlessly encapsulates each component of the STF/CNTs/UHMWPE system. The tensile strength and anti‐impact properties including punch residual velocity and energy absorbed are 564.0 ± 12.4 MPa, 1.537 ± 0.032 m/s and 22.952 ± 1.158 J in 12 ms, increased by 143.3%, 24.3% and 193.3%, respectively, compared to neat UHMWPE. This substantial performance uplift is attributed to multiple factors: the reinforcing friction between fibers/yarns fostered by the PVA binder and the full or partial embedding of CNTs, the additional reinforcing strength imparted by the CNTs matrix, and the dynamic viscosity enhancement of STF under impact forces. Anti‐impact felt was prepared by spraying PVA, CNTs, and STF onto UHMWPE. The tensile strength of anti‐impact felt was improved by 143.3%. The energy absorbed and impact depth was raised by 193.3%. The enhanced friction between fibers is caused by PVA and CNTs. The strength of CNTs and increased viscosity of STF under impact are notable. [ABSTRACT FROM AUTHOR]

For successful 3D printing based on stereolithography technologies, one of the most important factors influencing the success of printing is the dynamic viscosity of the prepared suspension. For the purposes of viscosity prediction at different volume fillings, two ZrO 2 powders with different yttrium content (CY3Z-RS and CY8Z-RS) with volume filling 0–40 % in two different dispersing mediums at two temperatures were investigated in this paper. The dependence of relative viscosity on volumetric filling was fitted by existing models and a new semi-empirical model based on experimental data was proposed and successfully plotted. Fitted data for all zirconia photosensitive suspensions showed a high correlation to the proposed model (R 2 from 97.02 % to 99.61 %). The model in addition to the possibilities of mathematical generalization of his prescription, introduces a fitting parameter C , which is thought to be thermodynamically influenceable and predictable. Furthermore, another key characteristic that is often neglected in rheological characterization, the stability of prepared ceramic suspensions, was verified either by rheological measurements but also by employing prospective technology based on analytical centrifuge. It was confirmed that all prepared suspensions were highly stable, and all instability indexes reached values less than 0.05. [ABSTRACT FROM AUTHOR]

Liposomal preparations play an important role as formulations for transdermal drug delivery; however, the electrical conductivity of these systems is sparingly evaluated. The aim of the study was to outline the range of the values of electrical conductivity values that may be recorded in the future pharmaceutical systems in the context of their viscosity. The electrical conductivity, measured by a conductivity probe of k = 1.0 cm−1, and the dynamic viscosity of liposomal and non-liposomal systems with naproxen sodium, embedded into a methylcellulose hydrophilic gel (0.25%), were compared with data from preparations without naproxen sodium in a range reflecting the naproxen sodium concentrations 0.1·10−2–9.5·10−2 mol/L. The specific conductivity covered a 1.5 μS·cm−1–5616.0 μS·cm−1 range, whereas the viscosity ranged from 0.9 to 9.4 mPa·s. The naproxen sodium highly influenced the electrical conductivity, whereas the dynamic viscosity was a moderate factor. The observed phenomena may be ascribed to the high mobility of sodium ions recruited from naproxen sodium and the relatively low concentrations of applied methylcellulose. The assembly of lecithin in liposomes may have lowered the specific conductivity of the systems with naproxen sodium. These measurements will be further developed for implementation as simple assays of the concentrations of active pharmaceutical ingredient in release experiments of preparations proposed for dermatological applications. [ABSTRACT FROM AUTHOR]

This work introduces and analyzes the mixed virtual element method on polygonal meshes for the numerical discretization of poro-elastodynamics models. For spatial discretization, we employ the mixed virtual element method on polygonal meshes, coupled with Newmark- β integration schemes for time discretization. We present a stability analysis for both the continuous and semi-discrete problems and derive error estimates for the energy norm in the semi-discrete case. Numerical experiments are conducted to verify the theoretical analysis, and the results on Voronoi meshes demonstrate that the algorithm effectively handles various dynamic viscosities. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The internal kink mode is one of the crucial factors affecting the stability of magnetically confined fusion devices. This paper explores the key features influencing the growth rate of internal kink modes using machine learning techniques such as Random Forest, Extreme Gradient Boosting (XGboost), Permutation, and SHapley Additive exPlanations (SHAP). We conduct an in-depth analysis of the significant physical mechanisms by which these key features impact the growth rate of internal kink modes. Numerical simulation data were used to train high-precision machine learning models, namely Random Forest and XGBoost, which achieved coefficients of determination values of 95.07% and 94.57%, respectively, demonstrating their capability to accurately predict the growth rate of internal kink modes. Based on these models, key feature analysis was systematically performed with Permutation and SHAP methods. The results indicate that resistance, pressure at the magnetic axis, viscosity, and plasma rotation are the primary features influencing the growth rate of internal kink modes. Specifically, resistance affects the evolution of internal kink modes by altering current distribution and magnetic field structure; pressure at the magnetic axis impacts the driving force of internal kink modes through the pressure gradient directly related to plasma stability; viscosity modifies the dynamic behavior of internal kink modes by regulating plasma flow; and plasma rotation introduces additional shear forces, affecting the stability and growth rate of internal kink modes. This paper describes the mechanisms by which these four key features influence the growth rate of internal kink modes, providing essential theoretical insights into the behavior of internal kink modes in magnetically confined fusion devices. [ABSTRACT FROM AUTHOR]

The article in the Journal of Fluid Mechanics delves into the analysis of laminar separation bubbles (LSBs) on a NACA0012 airfoil at low Reynolds numbers using advanced decomposition methods. The study identifies three dominant flow modes, including low-frequency modes governing the LSB and high-frequency oscillating modes with Kelvin-Helmholtz waves. The dynamics of the LSB are influenced by the energy content of these flow modes, leading to instability and bursting near stall conditions. The research also explores the implications of a bursting criterion based on global eigenmodes, providing valuable insights into the behavior and instability mechanisms of LSBs on airfoils. [Extracted from the article]

The text explores the relationship between drag coefficient and Reynolds number in cylinders, noting that surface roughness can contribute to additional scatter in the data. It highlights the impact of aspect ratio and Reynolds number on wake characteristics, showing transitions from steady flow to chaotic turbulence as Reynolds number increases. The study emphasizes the importance of considering cylinder geometry and surface roughness in understanding wake dynamics and drag coefficients. Additionally, the document provides a comprehensive list of research articles on fluid mechanics, focusing on vortex dynamics, wake-wall interactions, and forces acting on cylinders in various flow conditions. [Extracted from the article]

Engine oils are the lifeblood of any internal combustion engine, playing a crucial role in lubricating, cooling, and protecting its moving parts. They come in various formulations and viscosities, tailored to meet the specific needs of different engines. From enhancing performance to ensuring longevity, understanding engine oil types, properties, and functions is essential for maintaining a healthy and efficient engine. Given the high-strength properties of graphene-based nanoparticles, this study compares and analyzes the thermophysical performance of the commonly used SAE20W40 oil in automobile engines with Reduced Graphene Oxide (RGO) and Carboxyl Graphene (CG) mono and hybrid nanoparticles of 0.001% and 0.005%, respectively. This study aims to enhance the thermophysical properties of the SAE 20W40 oil and improve engine performance and the oil's life span. [ABSTRACT FROM AUTHOR]

This study investigated the effect of magnetic particle size and volume fraction on the shear yield stress and dynamic viscosity of magnetorheological fluids. Magnetorheological fluids with varying volume fractions of micro‐ and nanoscale magnetic particles were prepared. A plate‐on‐plate shear test bench was constructed to evaluate the fluids under a constant shear rate, with the applied current ranging from 0 A to 1.2 A. Results indicated that the shear yield stress initially increased and then decreased as the volume fraction of magnetic nanoparticles increased, reaching a maximum of 47 kPa at a volume fraction of 7 %. However, the excessive addition of magnetic particles or large‐diameter particles led to settling and reduced stability of the fluids. The findings suggest that optimizing the size and volume fraction of magnetic particles is crucial for maximizing the shear yield stress of magnetorheological fluids. [ABSTRACT FROM AUTHOR]

Magnetorheological elastomers (MREs) are in demand in the field of high-tech microindustries and nanoindustries such as biomedical applications and soft robotics due to their exquisite magneto-sensitive response. Among various MRE applications, programmable actuators are emerging as promising soft robots because of their combined advantages of excellent flexibility and precise controllability in a magnetic system. Here, we present the development of magnetically programmable soft magnetic microarray actuators through field-induced injection molding using MREs, which consist of styrene-ethylene/butylene styrene (SEBS) elastomer and carbonyl iron powder (CIP). The ratio of the CIP/SEBS matrix was designed to maximize the CIP fraction based on a critical solids loading. Further, as part of the design of the magnetization distribution in micropillar arrays, the magnetorheological response of the molten composites was analyzed using the static and dynamic viscosity results for both the on and off magnetic states, which reflected the particle dipole interaction and subsequent particle alignment during the field-induced injection molding process. To develop a high-aspect-ratio soft magnetic microarray, X-ray lithography was applied to prepare the sacrificial molds with a height-to-width ratio of 10. The alignment of the CIP was designed to achieve a parallel magnetic direction along the micropillar columns, and consequently, the micropillar arrays successfully achieved the uniform and large bending actuation of up to approximately 81° with an applied magnetic field. This study suggests that the injection molding process offers a promising manufacturing approach to build a programmable soft magnetic microarray actuator. [ABSTRACT FROM AUTHOR]

Recently, the development of composite materials from agricultural and forestry waste has become an attractive area of research. The use of bio-waste is beneficial for economic and environmental reasons, adapting it to cost effectiveness and environmental sustainability. In the presented study, the possibility of using hazelnut shell (HS) and hydrotalcite (HT) mineral filler was investigated. The effects of fillers in the amount of 10 wt.% on selected properties of polyurethane composites, such as rheological properties (dynamic viscosity, processing times), mechanical properties (compressive strength, flexural strength, hardness), insulating properties (thermal conductivity), and flame-retardant properties (e.g., ignition time, limiting oxygen index, peak heat release), were investigated. Polyurethane foams containing fillers have been shown to have better performance properties compared to unmodified polyurethane foams. For example, the addition of 10 wt% of hydrotalcite filler leads to PU composite foams with improved compression strength (improvement by ~20%), higher flexural strength (increase of ~38%), and comparable thermal conductivity (0.03055 W m–1 K–1 at 20 °C). Moreover, the incorporation of organic fillers has a positive effect on the fire resistance of PU materials. For example, the results from the cone calorimeter test showed that the incorporation of 10 wt% of hydrotalcite filler significantly reduced the peak of the heat release rate (pHRR) by ca. 30% compared with that of unmodified PU foam, and increased the value of the limiting oxygen index from 19.8% to 21.7%. [ABSTRACT FROM AUTHOR]

Sweetened condensed milk (SCM) is a product widely used by both consumers and other food production branches. However, it contains a lot of sucrose. This study aimed to examine the effects provided by sugar substitutes—trehalose, isomaltulose, and polydextrose—upon the SCM sensory profile and valuable quality indicators, such as water activity (Aw), viscosity, acidity, crystal size, and Maillard reaction potential (browning index, color change, loss of free AA). The study was performed by making model systems of SCM (MSCM) using the method of reconstitution of powdered ingredients. All the presented carbohydrate compositions in MSCM provided Aw value typical of intermediate-moisture food, which contributes to the long-term shelf life of the product. However, only 2 MSCM showed stability of Aw within a 14-d storage period: a composition of isomaltulose and trehalose (each at 22.55%), and a composition of trehalose (28.19%), sucrose (5.64%), polydextrose (5.64%), and isomaltulose (5.64%). Trehalose and polydextrose in MSCM with monocarbohydrate added fraction demonstrated their high structure-forming ability, expressed in high values of dynamic viscosity (>30 Pa·s). The MSCM containing a predominant amount of trehalose in the carbohydrate compositions (≥50%) showed lower average crystal size (<16 μm) compared with MSCM with di- and tetra-carbohydrate added fractions with predominant amounts of isomaltulose or polydextrose. Isomaltulose and polydextrose added to MSCM led to pronounced browning, whereas trehalose and sucrose reduced this effect in MSCM with di- and tetra-carbohydrate added fractions. Polydextrose added at 22.55% to carbohydrate fraction of MSCM caused bitterness, whereas the addition at 5.64% did not affect the taste. Based on the results of all the research conducted, the optimal carbohydrate compositions to produce SCM with fewer calories, lower sucrose content, and stable, adequate values of processing and sensory properties were trehalose (22.55%) with isomaltulose (22.55%), and trehalose (28.19%) with sucrose (5.64%), polydextrose (5.64%), and isomaltulose (5.64%). The list of standard abbreviations for JDS is available at adsa.org/jds-abbreviations-24. Nonstandard abbreviations are available in the Notes. [ABSTRACT FROM AUTHOR]

The interactions of naturally occurring polymers and medicaments, sodium carboxymethyl cellulose (Na-CMC) and Paracetamol (PCM), have attracted the interest of researchers in a variety of biomedical and pharmaceutical applications areas, such as drug delivery, cosmetics and tissue engineering. In our research described here, the effects of temperature and concentration of Na-CMC/PCM/water (W) mixed solutions were studied at various temperatures ranging from 20 °C to 45 °C. We highlighted that different regions can be distinguished in the aqueous Na-CMC/PCM/W complexes, depending on the composition and electrostatic interactions of the solutions, which are associated with significantly different phase behaviors. [ABSTRACT FROM AUTHOR]

In the present study, an effort was made to determine the effects of a porous matrix with different viscosities on the dynamic and static behaviors of rough short journal bearings taking into account the action of a squeezing film under varying loads without journal rotation. The micropolar fluid was regarded as a lubricant that contained microstructure additives in both the porous region and the film region. By applying Darcy's law for micropolar fluids through a porous matrix and stochastic theory related to uneven surfaces, a standardized Reynolds-type equation was extrapolated. Two scenarios with a stable and an alternating applied load were analyzed. The impacts of variations in viscosity, the porous medium, and roughness on a short journal bearing were examined. We inspected the dynamic and static behaviors of the journal bearing. We found that the velocity of the journal center with a micropolar fluid decreased when there was a cyclic load, and the impact of variations in the viscosity and porous matrix diminished the load capacity and pressure in the squeeze film and increased the velocity of the journal center. [ABSTRACT FROM AUTHOR]

The purpose of the work is to build the rational system for regulating technological parameters of the single-screw extruder using the frequency-regulated electric drive with limited use of sensors. This goal is achieved by the way of solving the following problems: development the method for controlling the technological parameters of the extruder with a controllable electric drive; development of a structural diagram of a model for estimating the speed of rotation a rotor of the engine without the use of velocity-type transducers; development of a functional diagram of the vector frequency-regulated electric drive with an observer that is built on the basis of a voltage equation corresponding to the main magnetic flux; development of a simulation model of the system of adjustable electric drive of the extruder and carrying out simulations with using the Matlab software package in the environment of Simulink. The most significant results of the researches are: the proposed algorithm for controlling the technological parameters (dynamic viscosity and pressure) by the way of calculating of the electrical power parameters of the adjustable electric drive of the extruder without the use velocity-type transducers; the functional diagram of the vector frequency-regulated electric drive of the single-screw extruder with the observer that was built on the basis of balance of the reactive capacity provides the necessary values of the technological parameters of the extruder. Changes in dynamic viscosity and pressure in the material, provides flexible adjustment without the use of speed sensors and rational use of electricity.

We present a falling-sphere viscometer with a magnetized sphere and fluxgate magnetometers continuously measuring the magnetic field produced at the sensor positions by the falling sphere. With a fluid volume of 15 ml and within a few seconds, we directly measure dynamic viscosities in a range between 200 and 3000 cP with a precision of 3%. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The study examines the dimensionless height of vortex centers in evaporating droplets on non-wetting substrates, finding that it remains constant for both axisymmetric toroidal vortex flow and non-axisymmetric single vortex flow at different contact angles. The research reveals a transition from axisymmetric to non-axisymmetric flow patterns with increasing substrate temperature, droplet volume, and contact angle, attributed to flow instability due to small perturbations. The critical Rayleigh number for this transition is influenced by the contact angle, and the heat transfer efficiency inside the droplets improves with the shift to non-axisymmetric flow patterns. The study offers valuable insights into the energy minimization aspect of flow transitions in droplets. [Extracted from the article]

The article delves into the behavior of dense granular suspensions in large drops, examining the interplay between gravitational and viscous forces. It reveals that the spreading of these suspensions follows a power-law pattern typical of gravity-driven dynamics, with a lower effective suspension viscosity compared to the bulk value. As the drop height nears the particle size, the power law breaks down as particles solidify while the contact line continues to advance. The study also investigates how particle size and volume fraction influence spreading behavior, illustrating the shift from fluid-like to discrete particle behavior. Various scientific experiments and studies by researchers like Richardson, Zaki, and Roché contribute to understanding phenomena such as sedimentation, fluid thinning, and droplet spreading, shedding light on wetting, rheology, and particle-laden droplets in airflow. These investigations offer valuable insights into the intricate behaviors of fluids and particles under different circumstances. [Extracted from the article]

Zinc oxide, due to its unique physicochemical properties, including dual piezoelectric and semiconductive ones, demonstrates a high application potential in various fields, with a particular focus on nanotechnology. Among ZnO nanoforms, nanorods are gaining particular interest. Due to their ability to efficiently transport charge carriers and photoelectric properties, they demonstrate significant potential in energy storage and conversion, as well as photovoltaics. They can be prepared via various methods; however, most of them require large energy inputs, long reaction times, or high-cost equipment. Hence, new methods of ZnO nanorod fabrication are currently being sought out. In this paper, an ultrasound-supported synthesis of ZnO nanorods with zinc acetate as a zinc precursor has been described. The fabrication of nanorods included the treatment of the precursor solution with ultrasounds, wherein various sonication times were employed to verify the impact of the sonication process on the effectiveness of ZnO nanorod synthesis and the sizes of the obtained nanostructures. The morphology of the obtained ZnO nanorods was imaged via a scanning electron microscope (SEM) analysis, while the particle size distribution within the precursor suspensions was determined by means of dynamic light scattering (DLS). Additionally, the dynamic viscosity of precursor suspensions was also verified. It was demonstrated that ultrasounds positively affect ZnO nanorod synthesis, yielding longer nanostructures through even reactant distribution. Longer nanorods were obtained as a result of short sonication (1–3 min), wherein prolonged treatment with ultrasounds (4–5 min) resulted in obtaining shorter nanorods. Importantly, the application of ultrasounds increased particle homogeneity within the precursor suspension by disintegrating particle agglomerates. Moreover, it was demonstrated that ultrasonic treatment reduces the dynamic viscosity of precursor suspension, facilitating faster particle diffusion and promoting a more uniform growth of longer ZnO nanorods. Hence, it can be concluded that ultrasounds constitute a promising solution in obtaining homogeneous ZnO nanorods, which is in line with the principles of green chemistry. [ABSTRACT FROM AUTHOR]

The article "Spreading of a viscous drop after impact onto a spherical target" in the Journal of Fluid Mechanics explores the dynamics of liquid droplets colliding with solid spherical particles. It investigates both non-axisymmetric and axisymmetric impacts, analyzing parameters such as drop shape, residual film thickness, and spreading angle. The study introduces a new method for measuring liquid viscosity during drop impacts, with potential applications in industrial processes. The research sheds light on optimizing processes involving drop collisions and offers valuable insights for various industries. [Extracted from the article]

The article "Enhanced bubble growth near an advancing solidification front" delves into the initial growth of gas bubbles near advancing ice fronts, highlighting the role of diffusion and gas concentration gradients in this process. Through experimental and numerical investigations, the study uncovers the rapid growth of bubbles due to gas accumulation at the front, emphasizing the intricate balance between freezing rates and mass transfer. The research also examines the impact of fluid flow on bubble growth, offering insights into the complex dynamics near moving interfaces with implications for materials science and environmental research. [Extracted from the article]

China's coal seam permeability is low, and the original coal seam gas extraction is difficult. CO2 displacement of coal seam CH4 technology is an effective gas extraction technology. CO2 is injected into the coal seam under pressure, and competitive adsorption occurs with CH4 in the pores. The gas composition is nonuniformly distributed, and its viscosity μ is the dynamic parameter. As the gas is compressible, the pressure drops, and migration distance does not satisfy a linear relationship. Therefore, the gas transport does not conform to Darcy's law. The mass transfer process and a multicomponent gas competitive adsorption were investigated theoretically and experimentally. The adsorption characteristics and gas compressibility determine the distribution of the gas components in pores and change the gas dynamic viscosity in different regions. The change in the gas dynamic viscosity in the channel is the direct reason for the nonlinear pressure gradient and gas flow curve. The permeability and gas component affect the degree of nonlinear deviation of the gas flow and pressure gradient curve. This affects the nonlinear deviation degree of the curve by changing the gas dynamic viscosity in the pore channel during displacement. The reasonable displacement pressure is the critical pressure (PO) through experimental and theoretical analysis. [ABSTRACT FROM AUTHOR]

The production evaluation of high-temperature and high-pressure gas condensate remains unsatisfactory in terms of precision due to the inadequate knowledge of viscosity variation and dynamic relative permeability. Here, we first conduct phase behavior experiments to clarify the mechanisms of viscosity variation followed by core flooding experiments to reveal the dynamic relative permeability. The viscosity variation responses in different regimes to pressure and temperature increases. Besides, the carbon number of the gas condensate exhibits three influencing scenarios on viscosity variation at different pressure and temperature conditions. Moreover, the variation of relative permeability is limited within 5% as temperature decreases together with pressure decreases, but the decline rate of pressure is expected to be higher than that of temperatures. We then theoretically model the production of the gas condensate reservoir by integrating the viscosity variation and dynamic relative permeability mechanisms obtained from the experiments. Modeling results well fit the field data. We adopt the model to analyze and elucidate the effects of temperature, pressure and fracture size on water flooding recovery of ultra-deep gas condensate reservoirs. We figure out that at high temperature, the gas condensate recovery can be enhanced by a rapid pressure decline which can further accelerate the oil thinning and gas condensate production. A high gas condensate production is obtained in the early stage at high pressure, but the oil with high viscosity consumes vast amounts of reservoir energy, leading to a rapid pressure drop in the early development stage. This work pioneers in revealing the interactive mechanisms of viscosity variation and dynamic permeability of ultra-deep reservoir during water flooding development, and brings insights into more adequate gas condensate recovery evaluation. [ABSTRACT FROM AUTHOR]

Due to relatively high terrain and negligible active tectonics, the southern Africa region boasts over 30 independent estimates of dynamic topography. These published estimates display a wide variance due to both the variety of methods used in computation and a lack of constraints on the regional mantle structure. Here we show that a focus on regional mantle structure is important to generate models of lithospheric and mantle dynamics. Global average mantle properties are not representative of a particular region, and it is necessary to generate viscosity profiles specific to a region of interest. We develop a Bayesian inversion using dynamic geoid kernels, existing seismic tomography models, and Slepian functions to invert for a localized radial viscosity profile that best explains the geoid in southern Africa. With an understanding of viscosity uncertainty, we constrain dynamic topography in southern Africa to lie between 1,000 and 2,000 m. Additionally, we model vertical displacements from 112 Global Navigation Satellite System stations across our region to examine the long‐term, long wavelength pattern of present‐day vertical motion, suggesting that a mean of 1.5 mm/yr (1σ $\sigma $: 0.8–2.0 mm/yr) of vertical motion may be related to ongoing dynamic topography. Our study demonstrates the utility of dynamic geoid kernels in local nonlinear inversions of non‐unique geophysical data. Furthermore, we present evidence that the mantle beneath southern Africa is generating significant dynamic support for and vertical displacement of the lithosphere in this region. Plain Language Summary: The high topography of southern African is a result of the interaction between the lithosphere and the mantle beneath the region, a process referred to as dynamic topography. The viscosity of Earth's mantle is a primary driver of the buoyancy forces that generate this dynamic topography. There is significant disagreement regarding the amplitude and pattern of dynamic topography in this region, partially owing to the lack of constraints on inputs to geodynamic models, especially viscosity. We use the geoid to constrain mantle viscosity within our study region by combining existing statistical techniques in a novel manner. We generate models of mantle viscosity, dynamic topography, and present‐day vertical displacement for our study region. Our preferred model results in 1,000–2,000 m of dynamic topography, suggesting that the whole of southern Africa is dynamically supported. We also find evidence for around 1.5 mm/yr (1σ $\sigma $: 0.8–2.0 mm/yr) of present‐day vertical displacement within the southern part of the region, suggesting that dynamic topography is currently increasing. We argue that the viscosity within any given region of the mantle differs significantly from the whole‐mantle average, and care must be taken to use a viscosity model that corresponds to the region of interest when creating geodynamic models. Key Points: We generate Bayesian estimates of localized radial mantle viscosity and dynamic topography in southern AfricaWe model present‐day vertical displacement of southern African using Global Navigation Satellite System station timeseries and Slepian localization techniquesThere is evidence for significant dynamic support (>1,000 m) and present‐day vertical motion (1s: 0.8–2.0 mm/yr) due to mantle dynamics [ABSTRACT FROM AUTHOR]

This work uses an alumina wheel to investigate the eco-benign grinding for better surface integrity of Inconel 625 (IN 625). To achieve this, applying nanofluids (NFs) with the minimum quantity lubrication (MQL) principle has been adopted, aiming at eco-benign grinding practices. In this work, MoS 2 NFs, MWCNTs NFs and hybrid NFs (prepared by mixing MoS 2 and MWCNTs in a 1:1 ratio) prepared using deionized water as the base fluid have been used. An in-house developed MQL setup is used to aim the NFs inside the grinding zone. The first attempt has been made to grind IN 625 in these environments. The characterisation of NFs in terms of nanofluid stability, dynamic viscosity, thermal conductivity and surface wettability have been performed before their utilization in grinding operations. A comparison has been made between the results obtained from NFs grinding and those from dry and soluble oil-based MQL grinding. It has been found that hybrid NFs provide excellent lubrication and cooling effects, reducing grinding forces and improving surface quality. Moreover, scanning electron microscopy, energy-dispersive spectroscopy and X-ray photon spectroscopy are applied to investigate the ground surfaces under different grinding conditions. Also, residual stress (with the help of X-ray diffraction and electron backscattered diffraction) and microhardness have been determined to gain further insights into the grinding behaviour. The wheel and chip morphology analyses have been performed to support the findings. The findings from this investigation lead to the conclusion that applying nano-MQL improves grinding effectiveness and promotes cleaner grinding outcomes. Hybrid NFs prove especially effective, as the physical synergistic effect enhances and safeguards the surface integrity of the produced ground components. [Display omitted] • This work endorses the grindability improvement of Inconel 625 using nano-MQL. • Thermos-physical and tribological characteristics of developed nanofluids have been investigated. • Ground surfaces have been investigated using SEM, EDS, EBSD, XRD and microhardness techniques. • Findings have been corroborated with the wheel and chip morphology investigations. • Nano-MQL has shown promising results in grindability improvement of Inconel 625. [ABSTRACT FROM AUTHOR]

The importance of chitosan (CH) has grown significantly over the last two decades due to its renewable and biodegradable source, and also because of the recent increase in the our knowledge of its functionality in technological and biomedical applications. The present article reviews the biopolymer CH and its derivatives, as versatile biomaterials for potential drug delivery systems, as well as tissue engineering applications, analgesia and treatment of arthritis. CH and its derivatives, as natural antimicrobial agents, can be applied in biomedical, biotechnological, and pharmaceutical applications. Its antimicrobial activity depends on many factors such as its molecular size, source, associated components, concentration, and type of microorganism. In our research described here we prepared and characterized the dynamic viscosity and the rheological properties of a biopolymer material based on CH in solution in acidic water. The dynamic viscosity and shear stress were measured under the influence of an increasing CH concentration of 1–10 g/l and an increasing temperature of 288.15–318.15 K. [ABSTRACT FROM AUTHOR]

Sodium carboxymethylcellulose Na-CMC is derived from cellulose fibers. Knowledge of the behavior of Na-CMC as a charged polysaccharide in solution is important, because most of its biomedical industrial applications utilize its solutions. The main objective of our research described here was to determine the rheological and viscometric properties of polysaccharide solutions of Na-CMC in water (W), as a function of the cutting speed and the polymer concentration. The evolution of reduced dynamic viscosities and the effect of the Gibbs energy of Na-CMC in W were characterized as a function of the temperature (15 °C to 45 °C), and concentration (1 to 10) g/l. We identified three main concentration regimes, corresponding to a dilute regime, a critical regime, and the semi-dilute regime. The thermodynamic parameters of the viscosity also supported the obtained results. Our results show that Na-CMC/W is a promising solvent mixture for use in pharmaceutical and antibacterial applications. [ABSTRACT FROM AUTHOR]

In order to improve the ductility and crack resistance of asphalt at low temperatures, St-Ba random copolymer was prepared by free radical polymerization with butyl acrylate (BA) as soft monomer and styrene (ST) as hard monomer. The copolymer was used as the modifier to modify asphalt, and the modification process was optimized. The ductility and bending beam rheology (BBR) properties of modified asphalt at different temperatures were studied. The results showed that: 1) the low temperature ductility of the modified asphalt was greatly improved, and the ductility of the modified asphalt at 10 °C increased from 16 cm to 136 cm at 2% copolymer content. 2) The BBR results showed that the cracking resistance of modified asphalt at low temperatures was improved. The creep rate of the modified asphalt with 6% copolymer content was increased by 12.1%, and the creep stiffness was decreased by 23.5%. 3) The optimum preparation scheme of copolymer modified asphalt is as follows: ST to BA ratio 2:8, copolymer content 6%, shear temperature 130 °C, shear time 5 min and shear rate 3000 r/min. 4) ST-BA random copolymer has little influence on the high temperature properties of modified asphalt (penetration degree, dynamic viscosity at 60 °C). [ABSTRACT FROM AUTHOR]

Accurate determination of physio‐chemical properties of polyethylene glycol as a green non‐toxic solvent is vital for any chemical and energy process involving polyethylene glycol. Machine learning algorithms are known as robust methods for prediction purposes. This study put forward least squares support vector machine scheme optimized with either particle swarm optimization, genetic algorithm and coupled simulated annealing optimization methods to precisely carry out the prediction task of polyethylene glycol viscosity in terms of its influencing parameters of pressure, temperature and polyethylene glycol molecular weight using a dataset containing experimental pertinent values. An outlier detection algorithm is made use of to confirm the data reliability for model development. In addition, sensitivity study is done to ascertain the relative impacts of each input factor on polyethylene glycol viscosity. The results showed that least squares support vector machine optimized with coupled simulated annealing is the most accurate model for the PEG viscosity prediction task with coefficient of determination of 0.997, average absolute relative error percent of 0.653 and mean square error of 8.005 for all datapoints. In addition, it was found that unlike temperature, we observe an indirect correlation of pressure and polyethylene glycol molecular weight with the pertinent viscosity data. The robustness of the developed least squares support vector machine optimized with coupled simulated annealing is further approved as it outperforms a renowned correlation that is often used for general viscosity prediction. [ABSTRACT FROM AUTHOR]