Homogeneous Parameters Research Articles

An accurate symplectic analysis for plane problems of functionally graded magneto-electro-elastic materials

Functionally graded (FG) magneto-electro-elastic (FGMEE) strictures are extensively utilized in various engineering applications, and the study of mechanical, electric, and magnetic behaviors is of paramount importance. This article presents an accurate and rational symplectic approach for two-dimensional problems of FGMEE media, with all material parameters varying longitudinally in an identical exponential form. Within the symplectic framework, the Hamiltonian-based canonical equation is derived directly and rigorously from the equilibrium equations and constitutive relations. Combined with the method of separation of variables and eigenfunction analysis, the analytical solutions of generalized displacements and generalized stresses are obtained by superimposing the symplectic eigenfunctions. Numerical examples are provided to verify the effectiveness and applicability of the proposed symplectic approach. Furthermore, a thorough analysis of the inhomogeneous parameter is carried out to enhance the design optimization of smart MEE structures.

Green fabricated bimetallic zinc ferrite nanoparticles mitigate oxidative stress-induced pathogenesis.

Current study evaluates the beneficial role of bio-functionalized zinc ferrite nanoparticles fabricated from an aqueous extract of Decalepis hamiltonii leaves (DHLE.ZnFe2O4 NPs) on sodium nitrite (NaNO2) and Diclofenac (DFC) induced oxidative stress in RBCs and Sprague Dawley male rat models. DHLE.ZnFe2O4 NPs were characterized using PXRD, FTIR, SEM-EDAX, HR-TEM and VSM. The data suggests that, DHLE.ZnFe2O4 NPs were crystalline, ellipsoidal in shape with an average size of 10.95 nm and super paramagnetic in nature. DHLE.ZnFe2O4 NPs exhibited anti-oxidant properties by scavenging DPPH, H2O2 and reducing ferric to ferrous ions. Furthermore, DHLE.ZnFe2O4 NPs normalized key parameters of oxidative stress such as LPO, PCC, TT and anti-oxidant enzymes (SOD &CAT). Similar to the previous in-vitro results, DHLE.ZnFe2O4 NPs restored all the said stress parameters in homogenates of the liver, kidney, pancreas and heart. In addition, DHLE.ZnFe2O4 NPs repaired Diclofenac induced tissue damage in the liver, kidney, pancreas and heart by regulating all biochemical parameters. Most importantly, DHLE.ZnFe2O4 NPs exhibited anti-inflammatory, anti-diabetic, anti-thrombotic activities and were non-toxic to RBCs. In conclusion, DHLE.ZnFe2O4 NPs through its anti-oxidant potential ameliorate oxidative stress induced pathogenesis such as, inflammation, tissue damage, diabetes and thrombosis.

Exploring bioconvective heat transfer dynamics on curved surfaces: Insights into non‐Newtonian behavior and multifaceted influencing factors

AbstractThis research article investigates the bioconvective flow of a second‐grade fluid along a curved surface, considering non‐Newtonian behavior and diverse influencing factors such as heat generation, chemical reactions, slip, Lorentz force, and viscous dissipation. By employing MATLAB's bvp4c tool and the similarity transformations, the nondimensional partial differential equations are solved. We discover that the stable and unstable solutions differ significantly from one another, which has significant consequences for industries including microfluidic devices and curved surface manufacturing. The study also examines the effects of homogenous and heterogenous reaction parameters on reactant concentrations, revealing that higher values reduce concentration, particularly for the second solution. Designing effective heat exchangers and chemical reactors requires consideration of the sensitivity of skin friction coefficient and Nusselt number to curvature, slip, and heat generation, as demonstrated by this work. The findings may guide future experimental study and yield important insights for optimization of bioconvective systems.

Investigation of the Effect of the Homogenization Regime on Energy Costs and Shelf Life of Yogurt with Dogberry Puree

Introduction. Homogenization is one of the most significant factors ensuring the successful implementation of the technology for manufacturing various dairy products. During this process, there are changed the properties and structure of proteins. In particular, there is decreased the size of casein micelles, which break down into submicells. After that, the accumulation of submicells on the surface of fat particles is likely. The increase in the homogenization pressure amplifies the mechanical effect on the particles, therefore, the average size of fat globules decreases.Aim of the Study. The study is aimed at reducing energy costs for manufacturing dairy products while ensuring the maximum preservation of the quality of dairy products.Materials and Methods. There has been studied the influence of homogenization pressure on the process technical parameters such as the power used for the homogenizer drive and for the dynamics of changes in the product properties during storage. The analytical dependences describing the main parameters of homogenization are considered.Results. Compliance with the recommended homogenization parameters and other para­meters, in particular heat treatment, can significantly increase the product shelf life without significant changes in the initial quality indicators. If the process conditions allow crushing the initial fat particles to a size of about 1.0 micrometer and distributing them evenly throughout the volume, it makes possible to get a significant improvement in the taste and consistency of the resulting products. There has been studied influence of homogenization parameters on the shelf life of yogurt manufactured according to the proposed formula with using southern fruits, in particular, with dogberries.Discussion and Conclusion. Taking into account the results of experimental studies, we have concluded that the energy costs are significantly affected by the homogenization pressure (absolute value) and the ratio of pressure values at various stages of homogenization. The product manufactured according to the proposed formula with crushed dogberries preserves good taste, microbiological properties, and physical and chemical specified parameters for 14–15 days. It follows that the shelf life of yogurt manufactured according to the proposed formula should not exceed more than fourteen days at a temperature of no more than +6 °C.

Dispersive and attenuation behavior of Love wave in a non-local highly heterogeneous media with imperfect contact condition

Abstract The primary aim of this study is to explore the impact of different physical parameters on the propagation of Love waves in non-local media. This study considers heterogeneous orthotropic viscoelastic properties within a layer and the variation of sandy medium properties with exponential depth, representing the half-space. Furthermore, the interface between the layer and the half-space is considered mechanically imperfect and perfect. The solutions of mechanical displacement of the layer and half-space are derived separately by solving the second-order hyperbolic type differential equation with the help of a variable-separable technique. A closed form of the dispersion relation is obtained using appropriate boundary conditions involving the medium's non-local elasticity and inhomogeneity parameters. Verification of the dispersion relation is shown by deriving some particular cases and comparing them with the classical dispersion relation of Love wave. The effects of physical parameters (like viscoelasticity, inhomogeneity, interfacial imperfection, sandy, non-locality, and \textcolor{blue}{thickness of the layer}) on the phase and attenuation phenomena of Love wave are investigated through numerical calculations and graphical representation. Furthermore, it is observed that the particle displacement in the layer decreases with depth, while in the half-space, the amplitude decreases oscillatory with depth, and the displacement gradually converges towards zero. A comparative graphical analysis of these parameters on the phase and attenuation characteristics of Love wave through the stratified Earth's structure with imperfect and perfect interfaces has been accomplished.

Тhermal history and fluid regime during the formation of Eldjurta massif of biotite granites (Greater Caucasus): reconstructions based on isotope (δ<sup>18</sup>О, δD) and geochemical data

Based on the geochemical and isotopic (δ18О, δD) data the thermal and fluid conditions during the formation of the Eldjurta granite massif were reconstructed. Analysis of rocks collected from the core of the Tyrnyauz Superdeep Well (TSW) within the depth range of 1427–3923 m revealed their homogeneous isotopic parameters: the δ18О values of bulk samples, quartz, feldspars, and biotite in 12 samples of biotite granites are 8.50 ± 0.33, 9.55 ± 0.22, 8.40 ± 0.33 and 5.45 ± 0.40‰, respectively. The δD values in the biotite vary from −103.3 to −95.6‰. The closure temperatures of the oxygen isotope system of quartz are 440–980°C. The rock cooling history was reconstructed using a new approach based on the analysis of single quartz grains. This approach can be used for detailed reconstructions of thermal history during formation of intrusive bodies. The definite samples were used to demonstrate that Dodson’s equation is valid for description of the δ18О values of quartz in a granite system. The data obtained suggest that the studied part of the massif was formed in at least two almost simultaneous stages. The lower part of the massif was crystallized first, and the second injection of granite melt arrived immediately after the first portion has been crystallized, but had no yet had time to cool significantly. The Тс values in the lower part of the massif indicate the reopening of the oxygen isotope system of quartz, with subsequent long-term isotope re-equilibration between minerals. This leads to decrease of the observed Тс values and the calculated cooling rates, which is related to increasing volume of the intrusive body and cooling within already heated rocks. Estimates of the isotopic parameters of the water component indicate the absence of exotic water fluid (meteoric or buried waters) during cooling of the massif. The variations of the δ18О values in the minerals of the Eldjurta biotite granites can be described only in terms of a simple retrograde exchange at the cooling stage

An Empirical Sample of Spectra of M-type Stars with Homogeneous Atmospheric-parameter Labels

The discrepancies between theoretical and observed spectra, and the systematic differences between various spectroscopic parameter estimates, complicate the determination of atmospheric parameters of M-type stars. In this work, we present an empirical sample of 5105 M-type star spectra with homogeneous atmospheric parameter labels through stellar-label transfer and sample cleaning. We addressed systematic discrepancies in spectroscopic parameter estimates by adopting recent results for Gaia EDR3 stars as a reference standard. Then, we used a density-based spatial clustering of applications with noise to remove unreliable samples in each subgrid of parameters. To confirm the reliability of the stellar labels, a five-layer neural network was utilized, randomly partitioning the samples into training and testing sets. The standard deviations between the predicted and actual values in the testing set are 14 K for T eff, 0.06 dex for logg, and 0.05 dex for [M/H], respectively. In addition, we conducted an internal cross validation to enhance validation and obtained precisions of 11 K, 0.05 dex, and 0.05 dex for T eff, logg, and [M/H], respectively. A grid of 1365 high-signal-to-noise ratio (S/N) spectra and their labels, selected from the empirical sample, was utilized in the stellar parameter pipeline for M-type stars of the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST), producing an almost seamless Kiel distribution diagram for LAMOST DR10 and DR11 data. The atmospheric parameters for M-type stars from LAMOST DR11 show improved precision compared to the data from DR9, with improvements (for spectra with S/N higher than 10) from 118 to 67 K in T eff, 0.2 to 0.07 dex in logg, and 0.29 to 0.14 dex in [M/H].

Assessment of landscape impact on snow chemical composition in terms of mineral geochemical exploration

In areas with cold climate seasonal snowpack is an attractive sampling material for geochemical exploration of deep mineral accumulations. However, previous studies on assessment of exploration efficiency of snow cover have paid little attention to snow composition variability conditioned by local landscape structure.The layered sampling of snow sections was performed in different landscape settings of the local area. The research area is characterized by the absence of ore mineralization zones and low anthropogenic load. The physical-chemical parameters and concentration of wide range of elements were identified in snowmelt. Multi-component data was integrated by means of factor principal component analysis. Besides, additive and differential geochemical indexes were used. The classification snow models were developed using hierarchical cluster analysis. The variance of chemical elements distribution and factor models of geochemical pattern were compared before and after reduction of background fluctuation. In terms of variation coefficient values of chemical elements the area has background parameters of chemical inhomogeneity. In total variance a lateral component prevails over a vertical one. The highest concentrations of chemical elements were found in snow section of forest landscape. It is necessary to take into account the fact of geochemical background fluctuation when interpreting the data of metal assay snow survey.After the reduction of lateral geochemical background fluctuation, the factor model has better classified the chemical elements in terms of their connection with soluble and insoluble occurrence forms. The values of differential index of liquid and solid phases have a similar satisfactory vertical variability in different landscapes. The analysis of chemical elements concentration reveals snow horizons that were or are affected by thaw and percolating water. The snow bottom layer, which is sampled at geochemical exploration, is not strong influenced by elution.

Torsion and Extension of Functionally Graded Mooney–Rivlin Cylinders

We analytically study finite torsional and extensional deformations of rubberlike material circular cylinders with the two material moduli in the Mooney–Rivlin relation assumed to be continuous functions of the undeformed radius. It is shown that under null resultant axial load on the end faces the cylinder length increases upon twisting. Furthermore, when the two moduli are affine functions of the radius the inhomogeneity parameters can be found to have the maximum shear stress occur at a pre-determined interior point. Whereas the radial stress is finite at the center of a cross-section of a homogeneous material cylinder, it may have large values for an inhomogeneous material cylinder. The closed-form solutions provided herein for the two moduli having affine, power-law and exponential functions of the radius should benefit numerical analysts verify their algorithms and engineers design soft material robots for improving their performance under torsional loads.

Impact of Titanium Cranial Implants on the Electric Field and SAR Distribution Induced by Mobile Phones Within the User’s Head

The purpose of this study was to determine the impact of a titanium cranial implant on the electric field distribution and the amount of energy absorbed from a cell phone within the human head. Three-dimensional lifelike models of the head of the mobile phone user, a titanium cranial implant, and a smartphone model was built. The head model consisted of sixteen homogeneous, isotropic domains, with permittivity and conductivity parameters taken from the literature. Numerical calculations were performed at the mobile communication frequency of 2600 MHz for a head model with and without a titanium cranial implant, in order to determine a field perturbation introduced by the implant. Our results show that in the presence of a titanium cranial implant, the electric field amplitude and SAR (Specific Absorption Rate) are increased within the layers close to the outer surface of the model (skin, fat tissue, and muscle). On the other hand, a cranial implant leads to a lower penetration depth, decreasing the electric field amplitude and SAR inside the skull, cerebrospinal fluid, and brain.

Computational role of homogeneous–heterogeneous chemical reactions and a mixed convective ternary hybrid nanofluid in a vertical porous microchannel

Abstract This article mainly scrutinizes the heat transfer and flow characteristics of a mixed convection ternary hybrid nanofluid in a porous microchannel considering the catalytic chemical reaction and nonuniform heat absorption/generation. Using appropriate similarity transformations, the modeled equations are converted into reduced ones and then solved via the Runge–Kutta–Fehlberg 4th/5th order method. To strengthen this analysis, the convection mechanism has been deployed. The effect of pertinent physical parameters on the fluid motion and thermal field is displayed, including some important engineering variables like the Nusselt number, Sherwood number, and drag force. The novel outcomes display that the flow reduces with porous permeability and nanoparticle volume fraction. The temperature of the nanofluid improves with nonuniform heat absorption/generation. The concentration decreases in the presence of both homogeneous and heterogeneous reaction intensities. The heat transfer rate enhances for the Eckert number, and a similar influence on the mass transfer rate is noticed for homogeneous reaction parameters. Further, the drag force declines for the Grashof number. The outcomes show that, in all cases, the ternary hybrid nanofluid shows a greater impact than the nanofluid. The attained findings represent applications in the era of cooling and heating systems, thermal engineering, and energy production.

On most informative regions for binary classification of schizophrenia based on resting state fMRI data done by selection of functionally homogeneous regions method

In this work we solve the problem of automatic binary classification of subjects with a diagnosis of schizophrenia and control groups on a data set obtained on a Siemens 3T tomograph. The data set included 36 subjects undergoing treatment at Psychiatric Hospital no. 1 Named after N.A. Alexeev of the Department of Health of Moscow (GBUZ PKB No. 1 DZM) and 36 subjects from the control group. Machine learning methods were used to solve this problem. As a result, an accuracy of 76% was achieved, which corresponds to the results obtained in other scientific studies. The highest accuracy was obtained for the local homogeneity parameter (regional homogeneity – ReHo), already known in the literature. At the same time, the set of features developed by the authors based on the method for identifying functionally homogeneous regions (FHR) gave a classification accuracy of 74%. But at the same time, the set of FHR features provides higher classification accuracy when using a small number of brain regions. For example, already in 8 regions, the FHR set provided an almost maximum classification accuracy of 72.5% (versus 65% for the ReHo set), which suggests that it is the selected 8 regions that give the highest level of separation.

Propagation and non-reciprocity in time-modulated diffusion through the lens of high-order homogenization

The homogenization procedure developed here is conducted on a laminate with periodic space–time modulation on the fine scale: at the leading order, this modulation creates convection in the low-wavelength regime if both parameters are modulated. However, if only one parameter is modulated, which is more realistic, this convective term disappears and one recovers a standard diffusion equation with effective homogeneous parameters; this does not describe the non-reciprocity and the propagation of the field observed from exact dispersion diagrams. This inconsistency is corrected here by considering second-order homogenization that results in a non-reciprocal propagation term that is proved to be non-zero for any laminate and verified via numerical simulation. The same methodology is also applied to the case when the density is modulated in the heat equation, leading, therefore, to a corrective advective term that cancels out non-reciprocity at the leading order but not at the second order.

Formulation and Antibacterial Activity Test of Ethanol Extract Gel of Laruna Root (Chromolaena odorata L.) Against Staphylococcus aureus and Propionibacterium acnes

Background: The formulation of gel preparations from laruna root extract (Chromolaena odorata L.) has been carried out using Na-CMC base accompanied by physical stability tests of the gel preparations. Objectives: to determine the physical stability of the laruna root extract gel preparation and its good concentration against Staphylococcus aureus and Propionibacterium acnes bacteria. Research method: The physical stability of the gel preparation was determined based on observations of changes in color, odor, shape, pH, uniformity, spreadability, and viscosity before and after storage for 6 cycles at temperatures of 4o C and 40oC. The pH test was carried out using a pH meter and viscosity measurements were carried out using a Brokfield viscometer. Results: The results of the study showed that the laruna root extract gel preparation was declared stable in the homogeneity indicator Results: The results showed that the gel preparation of laruna root extract could be said to be stable on homogeneity parameters where there were no solid particles in the preparation. Stable in good spreading power diameter, i.e. formulas 0, I, II, and III have a diameter of no more than 5-7 cm. For the results of measuring the viscosity of the gel preparation of laruna root extract, it is said to be stable because it is not more than 2000-4000 mPaS. For pH measurement, it is said to be stable because it has a pH in accordance with the quality requirements of skin preparations, which is 4.5-8.0. Conclusion: In the antibacterial activity test, a good clear zone result was obtained at a concentration of 0.3%.

SWEET-Cat: A view on the planetary mass-radius relation

Aims. SWEET-Cat (Stars With ExoplanETs Catalog) was originally introduced in 2013, and since then, the number of confirmed exoplanets has increased significantly. A crucial step for a comprehensive understanding of these new worlds is the precise and homogeneous characterization of their host stars. Methods. We used a large number of high-resolution spectra to continue the addition of new stellar parameters for planet-hosting stars in SWEET-Cat following the new detection of exoplanets listed both in the Extrasolar Planets Encyclopedia and in the NASA exoplanet archive. We obtained high-resolution spectra for a significant number of these planet-hosting stars, either observed by our team or collected through public archives. For FGK stars, the spectroscopic stellar parameters were derived for the spectra following the same homogeneous process using ARES+MOOG as for the previous SWEET-Cat releases. The stellar properties were combined with the planet properties to study possible correlations that could shed more light on the star-planet connection studies. Results. We have increased the number of stars with homogeneous parameters by 232 (~25% – from 959 to 1191). We focus on the exoplanets that have had both mass and radius determined to review the mass-radius relation, and we find results consistent with the ones previously reported in the literature. For the massive planets, we also revisit the radius anomaly, confirming a metallicity correlation for the radius anomaly already hinted at in previous results.

Multivariate additive subordination with applications in finance

We introduce a tractable multivariate pure jump process in which the trading time is described by an additive subordinator. The multivariate process retains the additivity property, and therefore is time inhomogeneous, i.e., its increments are independent but non stationary. We provide the theoretical framework of our process, perform a sensitivity analysis with respect to the time inhomogeneity parameters, and design a Monte Carlo scheme to simulate the trajectories of the process. We then employ the model in the context of option pricing in the FX market. We take advantage of the specific features of currency triangles to extract the joint dynamics of FX log-rates. Extensive tests based on observed market data show that our model outperforms well established pure jump benchmarks.

ANALYSIS OF SH-WAVES IN ANISOTROPIC FIBER-REINFORCED MEDIUM OVER LINEARLY VARYING INHOMOGENEOUS SUBSTRATE UNDER NON-LOCAL ELASTICITY

An analytical technique employing the variable separable method has been used in an attempt to precisely grasp and assess the impact of the property non-local elasticity upon the wave transmission response of an anisotropic fiber-reinforced material embedded over a semi-infinite, inhomogeneous medium that changes linearly. As depth increases, the stiffness and density of a semi-infinite substrate are believed to alter linearly. Availing the Whittaker function, a relation about dispersion has been acquired to analyze the response of SH waves. The visual representation depicts a significant influence of non-local elasticity on the propagation of SH-wave modes. Special cases have been found assessing the concurrency of the model with the original form equation of Love wave. The effects of non-locality, fiber-reinforcement parameters, and inhomogeneity parameters carry implications in designing and gradation of material characteristics some important parameters on the wave characteristics of the studied model.

Corrective and new research frontier of dual-phase -lag non-fourier heat conduction in functionally graded cylindrical materials with bi-directional property variations

This study presents a novel and corrective analysis of Dual-Phase-Lag (DPL) non-fourier heat conduction in functionally graded cylindrical materials with bi-directional property variations. For general purposes, the 2-D DPL model was employed and solved in a polar coordinate system for an FGM cylinder whose material properties vary exponentially in the axial and radial directions. The proposed model's analytical and numerical solutions were obtained through the SOV method and implicit FDM with a non-uniform grid. Moreover, the effect of the inhomogeneity parameter in the Fourier, Cattaneo–Vernotte (C–V), and DPL models has been analyzed. The results indicate that the DPL model achieves temperature stability in less time when contrasted with the C–V model. In addition, the reduced inhomogeneity parameters result in quicker attainment of a steady temperature and the induction of higher temperatures. The thermal wave propagation in the DPL model is consistently greater than that in the C–V model. In addition, an increase in time lag for heat flux enhances thermal wave properties (amplitude, wavelength, propagation speed etc.); conversely, an increase in time lag for temperature gradient counteracts wave properties and augments heat release. Nevertheless, the present outcomes offer a straightforward multivariate analytical and numerical solution for a finite cylinder's non-Fourier heat conduction equation under diverse boundary conditions.

Nonsequential double ionization of Ar in two-color inhomogeneous laser fields

With the classical ensemble method, we investigate the correlated electron dynamics in nonsequential double ionization (NSDI) of Ar in parallel two-color inhomogeneous laser fields with different inhomogeneity parameter ϵ. Numerical results show that at low laser intensities, the probability of NSDI is higher for two-color laser fields with a higher inhomogeneity parameter ϵ. At high laser intensities, however, the probability of NSDI decreases as ϵ increases. It is also shown that under low laser intensities, the two-color inhomogeneous laser fields drives the NSDI predominantly dominated by the RII channel, and the ratio of the RII channel increases as ϵ increases. More interestingly, an arc-like structure is found in the correlated electron momentum distributions for the two-color inhomogeneous laser fields. The underlying dynamics are revealed by tracing back to classical trajectories.

Effect of chemical reactions and melting heat on the dynamics of maxwell nanofluid flow

AbstractThis study investigates the electrically conducting Maxwell fluid flow over a stretching sheet with the effects of homogeneous‐heterogeneous chemical reactions, thermal radiation, and melting heat. The nanomaterial characteristics are analyzed considering Brownian motion and thermophoresis (Buongiorno's model). Irreversibility analysis is conducted to assess entropy generation. The governing equations of the problem are transformed into dimensionless equations through appropriate similarity transformations. The graphical and tabular numerical solutions are attained through NDSolve via Mathematica. The study examines how various parameters affect the velocity, concentration, temperature, and entropy generation within the flow. This study provides insights into isothermal chemical processes which contribute to the optimization of industrial and engineering applications. It is seen that heterogeneous diffusion parameter increases molecular disorder and rate of irreversible processes, whereas homogeneous diffusion parameter shows opposite trend.