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The time-evolution of dynamics as well as microstructure and mechanical response of phosphate-based geopolymers was probed using x-ray photon correlation spectroscopy and rheological tests. The analyzed relaxation processes in the freshly prepared geopolymer mixes evidenced a q-independent mode of the autocorrelation function, ascribed to density fluctuations of the already established molecular network, undergoing reconfiguration without significant mass transport. Upon curing, the detected motions are localized and depict a system evolving toward structural arrest dominated by slower hyperdiffusive dynamics, characterized by a compressed exponential regime, pointing to a structural relaxation process subjected to internal stresses, in a context of marked dynamical and structural heterogeneity. The system ages through a "densification" process producing declining small angle scattered intensity, as two finely intermixed gel-like reaction products, namely, one hydrated aluminophosphate and one hydrated silica, form a percolated network possessing surface fractal scaling of progressively shorter average correlation length. In this scenario, the nominal Al/P molar ratio of the mix, being an index of network-forming ability, is positively correlated with the dynamic viscosity and the overall kinetics, whereas the contrary occurs for the fraction of water. [ABSTRACT FROM AUTHOR]

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]

The naturally occurring polymers, chitosan (CH) and poly(N-vinyl-pyrrolidone (PVP), have attracted the interest of researchers in a variety of biomedical and pharmaceutical applications areas, such as drug delivery, cosmetics, and tissue engineering. However, PVP and CH have certain limitations for use in controlled aqueous CH/PVP mixed solutions. In this study aqueous solutions of PVP and CH with the same concentration of 10 g/l and pH 6 were mixed under atmospheric conditions. The effects of temperature and molar volume fraction, X1, of CH on the decreased dynamic viscosity of the CH/PVP mixed solutions were studied at various temperatures ranging from 15 °C to 80 °C. We highlighted that different regions can be distinguished in the aqueous CH/PVP complexes, depending on the composition and electrostatic interactions of the solutions, which are associated with significantly different phase behaviors. [ABSTRACT FROM AUTHOR]

The features of mixed convection heat transfer of a couple stress Williamson nanofluid flowing across a rotating perpendicular cone are examined in this research work. The non-Newtonian nature of the Williamson fluid and the impact of couple stresses, dynamic viscosity and viscous dissipation are considered. In order to improve heat conductivity, two different nanoparticles, one is silver and other titanium dioxide, are added in the base blood. Similarity transformations are used to convert the governing partial differential equations into a collection of nonlinear ordinary differential equations, which are then solved semi-numerically using homotopy analysis method. The effect of important parameters for temperature, velocity field, skin friction and Nusselt number is carefully investigated with the help of graphs and table. The obtained results show that the couple stress and Williamson parameters have a considerable impact on the behaviour of the boundary layer and its thermal properties. This information can be used to optimize heat transfer in complex fluid engineering applications. [ABSTRACT FROM AUTHOR]

In the present communication, we have reported the experimental measurements on the ($\rho $ρ) speed of sound (u) and dynamic viscosity (η) for furfural (FA), butyl acetate (BA), isobutyl acetate (IBA) and tert-butyl acetate (TBA) and their binary mixtures taking furfural as common component at T = (298.15, 303.15, 308.15) K over the entire composition range. The experimental data for density, speed of sound and dynamic viscosity were further utilised to compute excess molar volume (V_m^E), excess molar isentropic compression (K_(S,m)^E), excess speed of sound (u^E), dynamic viscosity deviation (Δη), excess Gibb’s free energy of activation for viscous flow (ΔG^(*E)) and partial molar volume (${\bar V_{m,i}}$Vˉm,i). Furthermore, these calculated properties have been correlated using a Redlich–Kister type polynomial equation through the method of least squares to estimate the binary coefficients. [ABSTRACT FROM AUTHOR]

The Republic of Kazakhstan has significant heavy oil and natural bitumen reserves. Some of these reserves contain highly viscous oil of more than 1000 mPa·s at shallow depths. The main recovery techniques are thermal methods, which use steam or hot water injections. One of the variants used to improve the thermal methods is the addition of a liquid or gaseous solvent. In this study, hexane was used as an additive solvent. The purpose of this study is to determine the effect of hexane on dead heavy oil in the Sarybulak field in the context of dynamic viscosity reduction. Mixtures of heavy oil and hexane in various proportions were prepared and studied. In addition, the dependence of the dynamic viscosity of heavy oil on the hexane content was evaluated. [ABSTRACT FROM AUTHOR]

This study focuses on the numerical observation of the convective motion of chemically active magnetohydrodynamic (MHD) fluid through a vertically oriented permeable medium, incorporating variations in mass and heat transfer. The fluid type is assumed to be incompressible, chemically strongly ionized and viscous with some mass infusibility. The model associated with this problem is solved by a highly stable Implicit Finite Difference Method (IFDM). The method is used for small and large deflection of the physical parameters, which results in a noticeable fluid flow behavior. Numerical configuration is graphically depicted to scrutinize the fluid behavior. The momentum, energy, concentration diffusion, skin friction, Nusselt number and Sherwood number are investigated for numerous factors such as magnetic field, permeability and chemical reaction rate. The current study unveils significant findings, demonstrating that a heightened rate of chemical reaction in the presence of magnetic effects, coupled with specific porosity, diminishes ionization energy, resulting in a concurrent decrease in the concentration and momentum profiles of the fluid flow. The rise in the viscous diffusion rate is attributed to escalating values of the Schmidt number, causing an augmentation in dynamic viscosity and consequently resulting in an overall reduction in the momentum of the fluid flow. [ABSTRACT FROM AUTHOR]

AbstractThis study investigates the rheological and compression behavior of cement-solidified dredged slurry with varying rice straw fiber contents (0–12%). Laboratory tests, including flow tests, viscosity measurements, and compression tests, were conducted to evaluate the influence of straw fibers on material properties. Results show that the slump flow value increased by 8.4% when fiber content increased from 0% to 0.5%, reaching a peak at 3% fiber content. Beyond 5% fiber content, slump flow decreased due to fiber entanglement and water absorption. The dynamic viscosity initially decreased as straw fibers released glucose, retarding cement hydration, but increased as fiber content surpassed 1%, due to increased water absorption and the formation of a fiber network. Yield shear stress also increased with fiber content, peaking at 5% fiber content, and was higher in fiber-reinforced slurries compared to non-fiber mixtures. Compression tests revealed that the compressibility of the solidified slurry increased with higher fiber content at early curing stages (28 days) but decreased with longer curing times (90–180 days). Compression yield stress increased initially with fiber content up to 1% but declined beyond this threshold due to fiber-induced porosity and disrupted cement bonding. [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]

The study presents experimental data of the viscosity and specific heat capacity of the near eutectic gallium–indium–tin alloy. Viscosity data cover the temperature range from the alloy's melting point of 283.85 K (10.70 °C) to about 370.47 K (97.32 °C). Two independent teams using a capillarity viscosimeter and an oscillating cup viscosimeter obtained almost identical values. Below 373 K (100 °C) the data follow the Arrhenius correlation. Specific heat capacity data result from differential scanning calorimetry measurements and reach from 236 K (− 37 °C) to 340 K (67 °C). The Neumann–Kopp rule gives neither the solid nor the liquid state a satisfactory representation of the data. Approximation functions represent these two regions separately in an excellent manner. The study discusses several issues related to the thermophysical properties, namely melting and crystallisation, and a possible liquid-to-liquid crossover. [ABSTRACT FROM AUTHOR]

ABSTRACT Full‐ceramic bearings possess numerous exceptional attributes, such as enhanced rigidity and superior resistance to wear. Nevertheless, full‐ceramic bearings consistently encounter elevated temperatures for extended periods of high‐speed operation, which easily affect the processing performance of the equipment. Lubrication viscosity has a significant effect on bearing heat generation, so it is meaningful to approach the effect of lubrication viscosity with respect to the dynamics of full‐ceramic bearings. Full‐ceramic angular contact ball bearings are treated as research objects to analyse their optimal working condition in this article. A coupled fluid–solid simulation model is constructed for analysis of the fluid and solid in the bearing cavity. First, at the conditions of different lubricant viscosity, the oil volume distribution, temperature field distribution in the bearing cavity is analysed. Then, the vibration characteristics of the inner ring is examined by constructing a dynamic model of the inner ring. Meanwhile, temperature and vibration variation of full‐ceramic bearings are verified through experiments under different rotational speeds. The results show that the lubricant volume distribution inside the bearing cavity is nonuniformly distributed, which the lubricant is mainly located in the outer ring groove position. Moreover, elevating the lubricant viscosity within a certain range promotes the enhancement of bearing lubrication properties. The maximum error of the bearing temperature between the simulation results and the experiment is 7.592%. Ultimately, the simulation analysis is validated through experiments, and it provides a theoretical foundation for selecting optimal parameters for the oil–air lubrication of full‐ceramic bearing. [ABSTRACT FROM AUTHOR]

Multifunctional nanosurfaces receive growing attention due to their versatile properties. Capillary force lithography (CFL) has emerged as a simple and economical method for fabricating these surfaces. In recent works, the authors proposed to leverage the evolution strategies (ES) to modify nanosurface characteristics with CFL to achieve specific functionalities such as frictional, optical, and bactericidal properties. For artificial intelligence (AI)-driven inverse design, earlier research integrates basic multiphysics principles such as dynamic viscosity, air diffusivity, surface tension, and electric potential with backward deep learning (DL) on the framework of ES. As a successful alternative to reinforcement learning, ES performed well for the AI-driven inverse design. However, the computational limitations of ES pose a critical technical challenge to achieving fast and efficient design. This paper addresses the challenges by proposing a parallel-computing-based ES (named parallel ES). The parallel ES demonstrated the desired speed and scalability, accelerating the AI-driven inverse design of multifunctional nanopatterned surfaces. Detailed parallel ES algorithms and cost models are presented, showing its potential as a promising tool for advancing AI-driven nanomanufacturing. [ABSTRACT FROM AUTHOR]

This article compares the rheological and tribological properties of three ionic liquids: Tributyl(methyl)phosphonium dimethyl phosphate 97%—MFCD, 1-Butyl-3-methylimidazolium hexafluorophosphate 97%—BMIMPF6, and 1-Butyl-3-methylimidazolium tetrafluoroborate 98%—BMIMBF4. Their density and kinematic viscosity at 20 °C and 40 °C were investigated, and tribological tests were carried out at the same temperatures with ball-on-disc contact. The test materials were made of 100Cr6 steel. A scanning electron microscope was used to image the wear tracks, while an EDS analyzer was employed to determine the chemical composition at the points of wear on the samples. A confocal microscope was used to analyze the geometric structure of the samples before and after the tribological tests. The results of the tests indicated that an increase in temperature reduced the dynamic viscosity of all the ionic liquids tested. At the same time, an increase in the MFCD and BMIMBF4 ionic liquid density and a decrease in the density of the BMIMPF6 ionic liquid were observed. The BMIMPF6 ionic liquid used for this study provided the lowest value of linear wear at both temperatures, ambient and 40 °C. However, for the BMIMBF4 ionic liquid, significant wear was observed for the tested discs and balls, with corrosive pitting on their surfaces. [ABSTRACT FROM AUTHOR]

Densities, dynamic viscosities, and refractive indices for four binary mixtures formed by dibutyl ether with ethyl caprylate, ethyl caprate, ethyl laurate or ethyl myristate over the whole composition range were measured at T=(293.15–323.15 K) and atmospheric pressure. The excess molar volume (VmE), viscosity deviation (Δη), and refractive index deviation (ΔnD) for the four systems are calculated and then correlated to the Redlich–Kister polynomial. The VmE and Δη values are all negative over the entire range of mole fractions. The absolute values of VmE for the mixtures increase with increasing temperature and the absolute values of Δη decrease with increasing temperature. The ΔnD values with the volume fraction for the four binary systems are all positive over the entire composition range. The experimental results can provide reliable data for the compatibility of biodiesels and their blended fuels. [ABSTRACT FROM AUTHOR]

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Horizontal well hydraulic fracturing technology has been widely used in the efficient development of shale gas to address the challenges posed by these reservoirs' low permeability and porosity. Despite the availability of numerous models for evaluating shale gas productivity post-fracturing, the effect of gas dynamic viscosity has been neglected. This study establishes a multiple-media and multiple-permeability coupled flow model based on the Barnett Shale and introduces Lee's correlation for gas viscosity. The model's feasibility and accuracy were verified by comparing the simulation results with the Barnett Shale data. The effects of reservoir damage, stimulation intensity, and fracture spacing on shale gas productivity are discussed. The results demonstrated that shale gas productivity decreased by more than 50% with intensified reservoir damage. Increasing stimulation intensity in the reservoir volume enhanced shale gas productivity. When the stimulation coefficient for the reservoir was increased from 0 to 2.5, the productivity increased by over 25%. A larger fracture spacing resulted in a smaller increase in shale gas productivity. Conversely, excessively narrow spacings significantly hindered productivity, resulting in an approximate 25% decrease. This study provides a theoretical reference for the productivity evaluation of horizontal wells in shale gas reservoirs. [ABSTRACT FROM AUTHOR]

This study aims to address the limited understanding of wash oil degradation in benzene units by analysing changes in the composition and properties of fresh and operating oils from different manufacturers. The findings will provide insights into the degradation pathways and stability of these oils. Gas chromatography/mass spectrometry was used to analyse the provided samples, and the dynamic viscosity of the oils was determined using a Brookfield LV DV2T rotational viscometer. During operation, the "heavy" oil (HO) becomes less volatile, while the "light" oil (LO) becomes slightly more volatile. The viscosity of the HO increases 1.25 times during operation. The LO is characterised by a higher total concentration of alkyl derivatives (48 wt.% compared to 44 wt.% for the HO). LO is enriched with naphthalene and indene, while HO loses 1- and 2-methylnaphthalenes and shows an increase in the concentrations of dibenzofuran, fluorene, anthracene, and phenanthrene. The oxidation products of LO include oxidised alkyl groups, while HO shows oxidised non-substituted hydrocarbons. The practical value of such studies lies in guiding the selection of fresh oil under current operating conditions. LO is more resistant to degradation as an absorbent than heavier wash oil. [ABSTRACT FROM AUTHOR]

Considering the harsh service environment of asphalt pavements in cold regions, there is an urgent need to develop high-viscosity, and high-elasticity modified asphalt. This study focuses on the composite modification effects of SBS (Styrene-Butadiene-Styrene) and TPS (TAFPACK-Super) modifiers. A multivariate regression analysis model was established to evaluate the effects of different external additive proportions on the properties of high-viscosity and high-elasticity modified asphalt, including softening point, penetration, ductility, and dynamic viscosity. The results indicate that the constructed quadratic nonlinear regression models exhibit excellent goodness of fit (0.929, 0.994, 0.882, and 0.939), verifying their reliability. The model further elucidates the influence patterns of different materials on asphalt properties: SBS has the greatest impact on the softening point and dynamic viscosity, TPS significantly enhances ductility, while aromatic oil primarily affects penetration. By considering performance and cost, an optimized formulation for TPS-SBS composite-modified asphalt was determined: 9% SBS, 1% TPS, and 3% aromatic oil. Validation tests demonstrate that the modified asphalt prepared with the optimal formulation meets all performance criteria, with a dynamic viscosity of 55.32 × 104 Pa·s at 60 °C. Additionally, this composite-modified asphalt exhibits excellent aging resistance, construction workability, and high-temperature stability, providing scientific support and reference for the development of durable asphalt pavements in cold regions. [ABSTRACT FROM AUTHOR]

Objectives. A quick cold start of emergency and auxiliary power units based on diesel engines should be possible at any time without problems and in the shortest possible time. The condition of the engine oil is one of the most important factors influencing the smooth start-up of power plants. During diesel engine operation, engine oil accumulates soot in its composition, negatively affecting its rheological properties. The aim of this research is to develop a mathematical model to describe changes in the dynamic viscosity of motor oils as a function of temperature. This model will account for the concentration of soot and its morphology, based on the results of experimental studies.Methods. Standardly used motor oils for diesel engines M-14D2SE and M-5z/14D2SE were used as oil samples in the preparation of model mixtures. The dispersed phase of the suspensions comprised carbon black of the N110, N220, N330, and N220 grades, characterized by a dusty (nongranular) texture. The rheological properties of the samples were determined using a TA Instruments DHR-2 rotational rheometer. The experimental data was subjected to mathematical statistical processing, in order to obtain approximating dependencies.Results. The paper presents an analysis of the various approaches to the description of the rheology of suspensions and the results of experimental studies of the viscosity-temperature characteristics (VTCs) of model samples of oils containing soot. The extant models of the dependence of the dynamic viscosity of suspensions on temperature, volume concentration of the dispersed phase, particle size and shape are demonstrated to be inadequate for the description of the VTCs of motor oils containing soot. A model of the rheological properties of soot-oil suspensions is proposed in the form of a mathematical dependence of their dynamic viscosity on temperature, mass concentration of soot, material density and size of soot particles, characteristics of the shape and structure of primary aggregates and the ratio of the sizes of aggregates and molecules of the dispersion medium.Conclusions. It was demonstrated that a comprehensive description of the VTCs of engine oils containing soot necessitates the consideration of the structural characteristics of the primary aggregates of soot particles. A mathematical model of the VTCs of oils was developed. This model is based on the dependence of the dynamic viscosity of oils on temperature, mass concentration of soot, density of the particle material, degree of non-sphericity of aggregates, the ratio of the particle sizes of the dispersed phase (either aggregates orsingle particles of non-aggregated soot) and oil molecules, and on the structure ofsoot, characterized by adsorption of dibutyl phthalate.

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]

Background. In complex tribological systems (CTS) of pulse loading, the reliability of friction units and the ability to predict their operating time before failure come to the forefront. Due to the ease of maintenance, the possibility of using in aggressive environments and contaminated conditions, high resistance to radial and vibration loads, themass use of plain bearings in such systems is justified. In this regard, timely diagnostics and prediction of operating time before failure of a plain bearing becomes an urgent problem. The purpose of the work is to mathematically model a plain bearing and calculate the lubrication boundary in the contact area. Materials and methods. The Reynolds equation for lubricant flow in a thin layer of a plain bearing is solved and the boundaries of the contact area are determined. Results. It is shown that on the curves of the dependence of the contact pressure on the coordinate in the contact area, a characteristic maximum appears, the position of which is asymmetrical relative to the boundaries of the lubricant. The coordinates of the lubricant boundary for the sliding bearing of the lifting mechanism of an artillery gun are found. Conclusions. The obtained results will allow us to find the mass flow rate of lubricant during servicing plain bearings, calculate the magnitude of sliding friction forces, and select the type of lubricant that increases the service life of the bearing.

Introduction. Development of broad-spectrum antibacterial medicines for treatment of bacterial and fungal infections of animal skin is an urgent task of pharmaceutical industry, medicine and agricultural industry. The most promising dosage form for the treatment of superficial infectious diseases is gel. The most important advantages are the absence of side effects associated with ingestion, as well as the formation of a protective film that prevents re-infection of the animal.Aim. To develop the composition of topical form in the form of gel on the basis of active pharmaceutical substance with a wide spectrum of antimicrobial action for therapy of infectious diseases of animal skin.Materials and methods. The object of the study was an original substance – thiadiazole derivative, obtained by the organic synthesis department of the Department of Organic Chemistry of the Federal State Budgetary Educational Institution of Higher Professional Education SPHFU of the Ministry of Health of Russia. Gel formers (sodium alginate and carbomer), propylene glycol, surfactants (surfactants), etc. were used in the work. The obtained thiadiazole gels were studied in terms of pH, appearance, thermostability, colloidal stability, film formation, in addition, the rheological properties of the gels were determined.Results and discussion. It was found that gels in which sodium alginate and carbomer acted simultaneously as gel formers had thixotropic properties providing the best stability of the structure. The gels in which glycerin was added formed an elastic film preventing damage and drying of the animal skin.Conclusion. As a result of this study, a topical formulation in the form of a gel containing a new thiadiazole derivative was developed for the treatment of infectious diseases of animal skin.

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.

The article delves into the dynamics of imbibition in a flattened triangular channel, focusing on the flow of liquid films in the corners. Two scenarios are considered: constant flow rate and constant pressure at the inlet, with a model that accurately predicts the evolution of the bulk meniscus and triple point positions. Experimental data validation confirms the model's accuracy, emphasizing the significance of corner films in understanding capillary flows in irregular channel geometries. The document also explores various studies on capillary imbibition, fluid dynamics, and capillary rise in different geometries, contributing to a deeper understanding of fluid behavior in diverse environments. [Extracted from the article]

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]

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]

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]

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 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]

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]

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]

In recent years, global climate change has caused worldwide trends in science and industry toward a focus on the development of modern technologies with reduced environmental impact, including reduced CO2 emissions into the atmosphere. The technology for producing asphalt mixtures (AM) at lower temperatures (WMA—warm asphalt mix) using zeolite materials for the bitumen foaming process fits perfectly into these trends. Therefore, towards the development of this technology, the research presented in this paper presents the modification process of zeolite NaP1 from fly ash with silanes of different chemical structures (TEOS, MPTS, TESPT) and their application in the foaming process of bitumen modified with polymers (PMB 45/80-55). The scope of the work includes two main novelty elements: (1) the use of zeolite–silane composites in bitumen foaming and (2) polymer-modified bitumen foaming. Chemical characterisation carried out by EDS-XRF, FTIR, and XPS analysis clearly demonstrated the success of the zeolite matrix modification process, which directly resulted in textural changes. Simultaneously, mineralogical analysis carried out by XRD showed the complete retention of the initial phase composition of zeolite matrix. Further studies have shown that the application of zeolite–oxide composites results in less PMB 45/80-55 stiffening without imposing negative effects on its softening point and dynamic viscosity. [ABSTRACT FROM AUTHOR]

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. [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]

In this study, butter and the corresponding buttermilk samples were produced with cream fermented by aromatic (A) or probiotic (P) cultures with or without complementary bioprotective culture (BC). The samples were characterised for their composition and colour parameters. Texture and rheological properties were evaluated at 10 and 20 °C. Microbiological (lactobacilli, lactococci, and yeast and mould counts) and sensory (aroma, taste, texture, and global evaluation) analyses were also performed. All butter sample characteristics were in accordance with the Portuguese standard. Regarding colour, the sample obtained with cream fermented by probiotics plus bioprotective culture (PBC) presented higher L* and b* values, indicating a slightly higher yellow chroma. However, colour differences (ΔEab*) in the butter samples were, in most cases, not detectable by a common observer. Butter samples P and PBC presented a significantly higher viscous modulus and consequently higher dynamic viscosity values (ca. log 6.5 Pa.s at 10 °C and log 5 Pa.s at 20 °C). Butter samples presented a pseudoplastic behaviour, and rheological parameters showed a high dependence on temperature. The counts of lactobacilli and lactococci in the butter samples were of the order of log 7–8 CFU/g, while yeast and mould counts were lower than log 2 CFU/g until the 30th day of storage, after which they showed a sharp increase to ca. log 5 CFU/g between the 30th and the 60th days of storage. Regarding sensory attributes of butter, sample P received the highest overall liking, followed by samples ABC and PBC. Sample A was the least appreciated. Buttermilk samples presented significant differences regarding their composition, viscosity, and colour parameters. In all cases, lactobacilli and lactococci counts exceeded log 7 CFU/mL after 30 days of storage, but yeast and mould counts were of the order of log 5–6 CFU/mL at the 15th day of storage. Samples P and PBC presented yeast and mould counts ca. 1–2 log cycles lower than samples A and ABC, indicating the potential of probiotic and bioprotective cultures to extend the shelf life of the product. Regarding the sensory attributes of buttermilk, samples P and PBC received the highest overall liking, followed by sample ABC. Sample A received the lowest scores, as had occurred with the butter samples. However, in all cases, the scores obtained by the buttermilk samples were lower compared to the ones of the corresponding butter. It can be concluded that both probiotic butter and buttermilk present high levels of lactobacilli and lactococci and can maintain their probiotic potential throughout the storage period. [ABSTRACT FROM AUTHOR]

This article is devoted to the scope of application and the possibility of expanding the use of vortex chamber pumps in various industries. Vortex chamber pumps are well-known as effective devices for pumping liquids and gases with the ability to pump solid particles, which makes them relevant in such areas as oil and gas, the chemical industry, water supply, industrial processing, and energy. Modeling of 3D airflow in vortex chamber pumps using numerical simulation methods in the open OpenFOAM package was carried out to gain a better understanding of their working process. In the calculation, the SST DDES turbulence model. The possibility of using this model appeared only in OpenFOAM version 3.0, with the implementation of an adjustment for the streamline curvature that equals 3. The results of the numerical analysis were compared with experimental data, which confirmed the model's adequacy. The obtained results show that calculated and experimental vacuum, created in the chamber of a pump in its operating mode with a closed outlet, values have excellent coincidence. This indicates the high accuracy of the selected model. The study also proves the prospects for using vortex chamber pumps in new industries and the possibilities for their further enhancement. [ABSTRACT FROM AUTHOR]

Using the existing two-dimensional experimental data and Open-source Fields Operation and Manipulation (OpenFOAM) software, this study performs a comprehensive comparative analysis of three types of landslide-generated tsunamis (subaerial, partially submerged, and submarine). The primary objective was to assess whether numerical simulations can accurately reproduce the experimental results of each type and to compare the predictive equations of the tsunami amplitudes derived from experimental and simulated data. The mesh size and dynamic viscosity parameters were initially optimized for a specific partially submerged landslide tsunami scenario and then applied across a broader range of experimental scenarios. Most of the simulated wave amplitudes remained within the 50% error margin, although significant discrepancies were observed between landslide types. When focusing on the crest amplitude of the first wave, the simulations of subaerial landslides least deviated from the experimental data, with a mean absolute percentage error of approximately 20%, versus approximately 40% for the partially submerged and submarine landslides. The predictive equations derived from the simulations closely matched those from the experimental data, confirming that OpenFOAM can effectively capture complex landslide–tsunami dynamics. Nonetheless, variations in the coefficients related to slope angles highlight the need for further calibration to enhance the simulation fidelity. [ABSTRACT FROM AUTHOR]