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Rice husk is an agricultural waste generated during rice milling and very rich in biosilica. Extraction, and modification of biosilica from rice husk were performed, and the isopropyl myristate oil-based emulsions stabilized by the modified biosilica nanoparticles were also studied. The native biosilica was modified by N-[3-(trimethoxysilyl)propyl] ethylenediamine. Characterization by energy-dispersive x-ray spectroscope showed that native biosilica contains oxygen (25.3%), silica (66.2%), and sodium (8.5%), and modified biosilica compositions are oxygen (31.6%), silica (39.4%), carbon (25.5%), and sodium (1.2%). X-ray diffraction analysis revealed that crystallite sizes of native biosilica and modified biosilica are 2.05 nm and 2.03 nm, respectively. The change in surface morphology as revealed by scanning electron microscopy confirmed that modification occurred. The emulsions stabilized by the modified biosilica nanoparticles were stable, while the emulsion stabilized by the native biosilica was not stable. The influence of pH on the stability and physical appearance of the emulsions was not significant. However, the water–oil ratio has significant influence on the stability of the emulsions and the optimal oil:water ratio was 80:20. The utilization of rice husk ash for the production of biosilica nanoparticles would reduce environmental pollution and health challenges associated with fly ash. The results from this study showed that modified biosilica nanoparticles is a good emulsifier and promising material in cosmetics and pharmaceutical applications. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new tritrophic food chain model. We address the conditions for the coexistence of two different zooplankton species and one phytoplankton species. The results of the numerical and analytical studies of the model show that the most relevant parameters influencing the plankton ecosystem, to maintain a stable coexistence equilibrium, are the: carrying capacity and the constant intrinsic growth rate of the phytoplankton population, and the conversion rate with a mortality rate of carnivorous zooplankton. We prove the existence and direction of Hopf bifurcation in non delay system. To account for the time delay in the conversion of herbivorous consumption to carnivorous zooplankton, we incorporate a discrete delay into the consume response function. Furthermore, we establish some adequate conditions to prove the occurrence of Hopf bifurcation induced by delay in the delayed model. We also plot two-parameter bifurcation diagrams. The numerical results support the analytical findings. [ABSTRACT FROM AUTHOR]

This work investigates the global dynamics of the bottom hole assembly with non-uniformly distributed cutters on drill-bit which improves stability of steady drilling. In this work, the drill string with a bottom hole assembly is considered as a lumped parameter model in the axial and torsional directions to accommodate axial and torsional vibrations, respectively. The regenerative effect due to the variation in the depth of cut is considered the only source of instability in the system. The engagement of individual cutters with the cut surface is modeled by formulating separate cut surface profile between two simultaneous cutters which is essential in capturing the true global dynamics of the system. Linear stability analysis through eigenvalue analysis reveals the system's improved stability compared to the system equipped with uniformly distributed cutters. An optimal distribution of cutters on the drill-bit for different number of cutters leading to the most stable steady drilling is obtained. This optimal distribution has been found to be robust with respect to changes in the rock strength as well as drill-rig parameters. A detailed nonlinear numerical analysis of the system with the optimal distribution reveals the existence of subcritical and supercritical Hopf bifurcation at different lobes of stability boundaries. Further analysis unveils various complex phenomenon, such as the co-existence of the steady solutions with the chaotic solution, partial bit-bounce, complete bit-bounce, and stick–slip vibrations. [ABSTRACT FROM AUTHOR]

This paper is concerned with the problem of an ellipsoid of revolution rolling on a horizontal plane under the assumption that there is no slipping at the point of contact and no spinning about the vertical. A reduction of the equations of motion to a fixed level set of first integrals is performed. Permanent rotations corresponding to the rolling of an ellipsoid in a circle or in a straight line are found. A linear stability analysis of permanent rotations is carried out. A complete classification of possible trajectories of the reduced system is performed using a bifurcation analysis. A classification of the trajectories of the center of mass of the ellipsoid depending on parameter values and initial conditions is performed. [ABSTRACT FROM AUTHOR]

In recent years, notable progress in computational density functional theory (DFT) has facilitated the collection of extensive datasets in the field of materials science. Machine learning is a crucial technique for effectively processing and analyzing these large datasets and accelerating the creation of new compounds. In this work, we employ the Extreme Gradient Boosting (XGBoost) classification algorithm to predict the crystal structure of 381 halides and oxide perovskites using 78 features. We achieved a classification accuracy of 76.62% for these materials. Subsequently, we utilized the Random Forest and XGBoost algorithms to investigate a dataset comprising 761 perovskite materials from the material project database to predict the band gap energy (best accuracy = 84.78%, mean absolute error(MAE) = 0.410 eV, root mean square error (RMSE) = 0.594 eV) and formation energy (best accuracy = 94.81%, MAE = 0.083 eV/atom, RMSE = 0.157 eV/atom), all of these prediction results based on the chemical formulas. Notably, the feature importance analysis shows the significant influence of the number of d electrons in the d orbit of the B atom on both band gap (Eg) and formation energy (EF) properties. Finally, we applied our prediction model to identify stable perovskite solar cells, achieving an accuracy of 85.18%. These findings provide valuable guidelines for the discovery of stable perovskite solar cells and help researchers tailor the composition of perovskite materials to optimize their light-harvesting capabilities, leading to higher-power conversion efficiencies. [ABSTRACT FROM AUTHOR]

This paper presents an inverse problem of identifying two ionic parameters of a nonlocal reaction-diffusion system in cardiac electrophysiology modelling. We used a nonlocal FitzHugh-Nagumo monodomain model which describes the electrical activity in cardiac tissue with the diffusion rate assumed to depend on the total electrical potential in the heart. We established at first, the global Carleman estimate adapted to nonlocal diffusion to obtain our main result which is the uniqueness and the Lipschitz stability estimate for two ionic parameters (k , γ) . [ABSTRACT FROM AUTHOR]

In this article, a new numerical algorithm for solving a 1-dimensional (1D) and 2-dimensional (2D) time-fractional diffusion equation is proposed. The Sinc-Galerkin scheme is considered for spatial discretization, and a higher-order finite difference formula is considered for temporal discretization. The convergence behavior of the methods is analyzed, and the error bounds are provided. The main objective of this paper is to propose the error bounds for 2D problems by using the Sinc-Galerkin method. The proposed method in terms of convergence is studied by using the characteristics of the Sinc function in detail with optimal rates of exponential convergence for 2D problems. Some numerical experiments validate the theoretical results and present the efficiency of the proposed schemes. [ABSTRACT FROM AUTHOR]

Purpose: Astaxanthin (AX), commonly used for dermal applications, exhibits anti-inflammatory and antioxidant activities; however, it has poor water solubility. In this study, we investigated the physicochemical properties of AX-containing particulates formulated using the amphiphilic graft copolymer Soluplus (polyvinyl caprolactam-polyvinyl acetate-polyethylene glycol graft copolymer: Sol) and polyethylene glycol-2000 (PEG 2000); in addition, the stability and skin applications of AX particulates were investigated. Methods: AX, Sol, and PEG were mixed by weight to prepare AX particles using the hydration method. The prepared particles were subjected to stability evaluations including particle size distribution, zeta potential estimation, and fluorescence spectroscopy as well as physical evaluations including 1H-1H NOESY NMR spectral measurement, powder X-ray diffraction, and differential scanning calorimetry. Functional evaluations included singlet oxygen scavenging, skin permeation test, and fluorescence microscopy. Results: Relatively stable particles of Sol/AX and Sol/PEG 2000/AX, approximately 100 nm and 125 nm in size, respectively, were formed at a mixed weight ratio (9/1) of 0.1 M Ascorbic Acid solution (0.1 M ASC) and a mixed weight ratio (8/1/1) of 0.1 M ASC, respectively, at 25 °C after storage for 14 days under light-shielded condition. Stability evaluations revealed a decrease in fluorescence intensity and color fading for Sol/AX = 9/1 and Sol/PEG 2000/AX = 8/1/1 (dispersion medium: distilled water); however, no change in fluorescence intensity of AX was observed immediately after preparation in Sol/AX = 9/1 and Sol/PEG 2000/AX = 8/1/1 (dispersion medium: 0.1 M ASC). The fluorescence intensity of AX did not fluctuate significantly immediately after adjustment, and the particles remained stable, showing a bright orange color with time. NMR spectra of Sol/AX = 9/1 and Sol/PEG 2000/AX (dispersion medium: 0.1 M ASC) showed the interactions between the CH3 group e from Sol (1.8 ~ 2.0 ppm) and the CH groups H-15,11 from AX (6.7 ~ 6.8 ppm), 8',12' (6.4 ~ 6.5 ppm), H-10,14 (6.4 ~ 6.5 ppm), and 7,7' (6.2 ~ 6.3 ppm), indicating the disappearance of cross peaks. Furthermore, new cross peaks were identified for the CH3 group e of Sol (1.8 ~ 2.0 ppm), the 7-membered ring z of Sol (1.5 ~ 1.8 ppm), the 5-membered ring S of ASC (3.5 ~ 3.6 ppm), the CH group T (3.8 ~ 3.9 ppm), and the CH group U (4.7 ppm). Fluorescence microscopy observations of microparticles formulated with Sol/PEG 2000/AX showed a slight improvement in skin penetration. Conclusion: New AX particulates were formed using Sol/PEG 2000/AX = 8/1/1, suggesting that Sol/PEG 2000/AX maintained the stability and improved the skin penetration of AX. [ABSTRACT FROM AUTHOR]

Most of the countries in the world are affected by the coronavirus epidemic that put people in danger, with many infected cases and deaths. The crowding factor plays a significant role in the transmission of coronavirus disease. On the other hand, the vaccines of the covid-19 played a decisive role in the control of coronavirus infection. In this paper, a fractional order epidemic model (SIVR) of coronavirus disease is proposed by considering the effects of crowding and vaccination because the transmission of this infection is highly influenced by these two factors. The nonlinear incidence rate with the inclusion of these effects is a better approach to understand and analyse the dynamics of the model. The positivity and boundedness of the fractional order model is ensured by applying some standard results of Mittag Leffler function and Laplace transformation. The equilibrium points are described analytically. The existence and uniqueness of the non-integer order model is also confirmed by using results of the fixed-point theory. Stability analysis is carried out for the system at both the steady states by using Jacobian matrix theory, Routh–Hurwitz criterion and Volterra-type Lyapunov functions. Basic reproductive number is calculated by using next generation matrix. It is verified that disease-free equilibrium is locally asymptotically stable if R 0 < 1 and endemic equilibrium is locally asymptotically stable if R 0 > 1 . Moreover, the disease-free equilibrium is globally asymptotically stable if R 0 < 1 and endemic equilibrium is globally asymptotically stable if R 0 > 1 . The non-standard finite difference (NSFD) scheme is developed to approximate the solutions of the system. The simulated graphs are presented to show the key features of the NSFD approach. It is proved that non-standard finite difference approach preserves the positivity and boundedness properties of model. The simulated graphs show that the implementation of control strategies reduced the infected population and increase the recovered population. The impact of fractional order parameter α is described by the graphical templates. The future trends of the virus transmission are predicted under some control measures. The current work will be a value addition in the literature. The article is closed by some useful concluding remarks. [ABSTRACT FROM AUTHOR]

Solid-state contact ion-selective electrodes (SC-ISEs) are an efficacious means of monitoring heavy metal contamination. Instability of the electrode potential is a key factor limiting their development, with biofouling in real water samples posing a significant challenge to maintaining stability. Therefore, addressing biofouling is crucial for optimizing solid-state ion-selective electrodes. In this work, high stability and antibiofouling capability in a solid-state contact lead ion-selective electrode (SC-Pb2+-ISE) based on polyaniline (PANI) was achieved through cathodic polarization. Specifically, PANI played a dual role in the ion-selective membrane (ISM) as an ion-to-electron transducer and antifouling agent. Given the excellent electrochemical performance of PANI, the prepared electrode (GC/PANI-Pb2+-ISM) demonstrated a remarkable antibiofouling efficiency of 98.2% under a cathodic polarization of -0.2 V. Furthermore, a standard deviation of standard potential (Eθ) as low as ± 0.5 mV was realized successfully. The excellent chrono-potentiometric stability of 17.0 ± 2.9 μV/s was also demonstrated. The electrode maintained a Nernstian response slope of 30.7 ± 0.2 (R2 = 0.998) after applying a cathode potential (-0.2 V) for 30 min. The developed GC/PANI-Pb2+-ISM electrode is suitable for practical applications in real environmental water sample monitoring. [ABSTRACT FROM AUTHOR]

Iron(III) complexes based on N,N´-bis(salicylidene)ethylenediamine (salene) scaffolds have demonstrated promising anticancer features like induction of ferroptosis, an iron dependent cell death. Since poor cellular uptake limits their therapeutical potential, this study aimed to enhance the lipophilic character of chlorido[N,N′-bis(salicylidene)-1,2-bis(3-methoxyphenyl)ethylenediamine]iron(III) complexes by introducing lipophilicity improving ligands such as fluorine (X1), chlorine (X2) and bromine (X3) in 5-position in the salicylidene moieties. After detailed characterization the binding to nucleophiles, logP values and cellular uptake were determined. The complexes were further evaluated regarding their biological activity on MDA-MB 231 mammary carcinoma, the non-tumorous SV-80 fibroblast, HS-5 stroma and MCF-10A mammary gland cell lines. Stability of the complexes in aqueous and biological environments was proven by the lack of interactions with amino acids and glutathione. Cellular uptake was positively correlated with the logP values, indicating that higher lipophilicity enhanced cellular uptake. The complexes induced strong antiproliferative and antimetabolic effects on MDA-MB 231 cells, but were inactive on all non-malignant cells tested. Generation of mitochondrial reactive oxygen species, increase of lipid peroxidation and induction of both ferroptosis and necroptosis were identified as mechanisms of action. In conclusion, halogenation of chlorido[N,N′-bis(salicylidene)-1,2-bis(3-methoxyphenyl)ethylenediamine]iron(III) complexes raises their lipophilic character resulting in improved cellular uptake. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have garnered significant interest in recent years due to their high energy conversion efficiency, unique properties, low cost, and simplified fabrication process. However, the reactivity of these devices to external factors such as moisture, water, and UV light presents significant challenges for their commercial viability, potentially compromising their long-term stability and functionality. To overcome these limitations, researchers have focused on two primary strategies: surface passivation and additive engineering. Recent research developments have shown that surface passivation and additive engineering using conducting polymers (CPs), metal-organic framework materials (MOFs), and inorganic additives have significantly improved the operability of perovskite solar cells (PSCs). CPs form resilient interactions with perovskite grains, enhancing film stability through cross-link bonds. MOFs possess a unique network of functional holes that interact with multiple perovskite layers, maintaining morphology and improving interlayer charge transport. Inorganic additives suppress defects at grain boundaries, promoting the formation and growth of perovskite absorbers while providing mechanical protection. These advancements contribute to overcoming the reactivity limitations of PSCs and bring us closer to the commercialization of this technology. The review focuses on the advancements in similar materials, their passivation principles, and the resulting effects on PSC performance. Key aspects covered include the device structure, targeted defects, passivation processes, and synthesis outcomes. By providing a comprehensive overview, the review aims to assist in the selection and synthesis of novel materials. [ABSTRACT FROM AUTHOR]

Due to their several attractive properties, BDF-type multistep methods are usually the method-of-choice for solving stiff initial value problems (IVPs) of ordinary differential equations (ODEs) and differential-algebraic equations (DAEs). Recently, a class of BDF-type methods based on linear barycentric rational interpolants (LBRIs), referred to as RBDF methods, was introduced for solving ODEs. In the present paper, we are going to introduce a new family of LBRIs-based BDF-type formulas for the numerical solution of ODEs and DAEs with desirable stability properties and smaller error constants than those of the RBDF methods. Numerical experiments of the proposed methods on some well-known IVPs for ODEs and DAEs with index ≤ 3 illustrate the efficiency and capability of the methods in solving such problems. [ABSTRACT FROM AUTHOR]

In this manuscript, we aim to study the semi-analytical and the numerical solution of a semilinear time-fractional diffusion equation where the time-fractional term includes the combination of tempered fractional derivative and k-Caputo fractional derivative with a parameter . The application of the new integral transform, namely Elzaki transform of the tempered k-Caputo fractional derivative is shown here and thereafter the semi-analytical solution is obtained by using the Elzaki decomposition method. The model problem is linearized using Newton's quasilinearization method, and then the quasilinearized problem is discretized by the difference scheme namely tempered - method. Stability and convergence analysis of the proposed scheme have been discussed in the -norm using the energy method. In support of the theoretical results, numerical example has been incorporated. [ABSTRACT FROM AUTHOR]

We explored two types of anticipatory synergy adjustments (ASA) during accurate four-finger total force production task. The first type is a change in the index of force-stabilizing synergy during a steady state when a person is expecting a signal to produce a quick force change, which is seen even when the signal does not come (steady-state ASA). The other type is the drop in in the synergy index prior to a planned force change starting at a known time (transient ASA). The subjects performed a task of steady force production at 10% of maximal voluntary contraction (MVC) followed by a ramp to 20% MVC over 1 s, 3 s, and as a step function (0 s). In another task, in 50% of the trials during the steady-state phase, an unexpected signal could come requiring a quick force pulse to 20% MVC (0-surprise). Inter-trial variance in the finger force space was used to quantify the index of force-stabilizing synergy within the uncontrolled manifold hypothesis. We observed significantly lower synergy index values during the steady state in the 0-ramp trials compared to the 1-ramp and 3-ramp trials. There was also larger transient ASA during the 0-ramp trials. In the 0-surprise condition, the synergy index was significantly higher compared to the 0-ramp condition whereas the transient ASA was significantly larger. The finding of transient ASA scaling is of importance for clinical studies, which commonly involve populations with slower actions, which can by itself be associated with smaller ASAs. The participants varied the sharing pattern of total force across the fingers more in the task with "surprises". This was coupled to more attention to precision of performance, i.e., inter-trial deviations from the target as reflected in smaller variance affecting total force, possibly reflecting higher concentration on the task, which the participants perceived as more challenging compared to a similar task without surprise targets. [ABSTRACT FROM AUTHOR]

The goal of this study was to undertake a detailed investigation of the agroecological state of the wheat and sugar beet ecosystems on a local scale. From 2001 to 2016, a set of the most critical agroecological indicators of wheat and sugar beet farming systems in the Torbat-e Heydarieh region, northeast of Iran, were studied. Potential yield calculations using both FAO and modified FAO methodologies revealed that potential yield was nearly consistent for both ecosystems over the research period in the region. The extent of the yield gap for both habitats decreased. The study of the regional yield factor revealed that improving the management system resulted in higher actual yield and thus a smaller yield gap in both ecosystems. In both ecosystems, there was a reduction in yield stability. The rate of ​nitrogen uptake efficiency, nitrogen utilization efficiency, and nitrogen use efficiency (NUE) all decreased during the studied years in the region. According to the findings, the primary cause of the increase in nitrogen consumption, growing intensification, and decreasing stability in the analyzed systems appears to be a deficiency of NUE and its downward trend. As a result, planning and altering management methods focusing on enhancing NUE may be proposed as the first step toward boosting sustainability in the Torbat-e Heydarieh wheat and sugar beet agroecosystems. [ABSTRACT FROM AUTHOR]

This article compared two high-order numerical schemes for convection-diffusion delay differential equation via two fractional operators with singular kernels. The objective is to present two effective schemes that give (3 - α) and second order of accuracy in the time direction when α ∈ (0 , 1) using Caputo and Modified Atangana-Baleanu Caputo derivatives, respectively. We also implemented a trigonometric spline technique in the space direction, giving second order of accuracy. Moreover, meticulous analysis shows these numerical schemes to be unconditionally stable and convergent. The efficiency and reliability of these schemes are illustrated by numerical experiments. The tabulated results obtained from test examples have also shown the comparison of these operators. [ABSTRACT FROM AUTHOR]

The extensive and widespread incorporation of wind farms into transmission networks produces many challenges. One of the necessities is to improve power transmission capability to transport large levels of wind energy over long distances. The development of series compensators is a proven method of increasing the power transmission capacity of existing transmission lines and it is of great importance for the grid integration of large wind farms. At the same time, series compensation lines create sub-synchronous resonance (SSR) problems in turbo generators. As a result, electrical unsteadiness may occur in the sub-synchronous frequency components and there is the possibility of failure in the turbo generator tube of the shaft. This paper proposes a novel approach for analyzing SSR in wind farms connected with voltage source inverter (VSI) based photovoltaic cells. The Genetic Window Optimization (GWO) algorithm is used to analyze the multiple electrical parameters that cause SSR. These parameters are the series compensation range, power generation and wind velocity. Steady-state stability is carried out through eigenvalues and participation factors under the various operating conditions of wind farms. The dynamic stability analysis is also achieved through simulations of electromagnetic transients using PSCAD/EMTDC software for the first IEEE bench mark system. Simulation results of wind farms are interfaced with a prototype of real-time photovoltaic cell. A hardware model of solar cells is also presented. The high-level accuracy of GWO results is compared with existing techniques such as Particle Swarm Optimization (PSO) and FIREFLY algorithms. [ABSTRACT FROM AUTHOR]

In this paper, we study Chaplain–Lolas model in three dimensional bounded domain, which describes the invasion and diffusion process of solid tumors during the vascular growth stage. Although the model has received extensive attention since it was proposed, the existence of solutions in three-dimensional space is still missing, and only a global small solution is established by Pang and Wang (Math Models Methods Appl Sci 28(11):2211–2235, 2018) with sufficiently small proliferation coefficient. As for long time behavior, there are only corresponding stability result of constant steady-state for the case without ECM remodelling (Hillen et al. in Math Models Methods Appl Sci 25(1):165–198, 2013; Tao and Winkler in SIAM J Math Anal 47:4229–4250, 2016). If the remodeling effect of ECM is considered, the relevant research is still blank. In this paper, we first pay our attention to the study of existence of global strong solution and long time behavior. We prove that when the ratio of cell proliferation coefficient to chemotactic intensity μ χ 2 is large, there exists a unique global strong solution around the equilibrium state (1, 1, 0), and the global strong solution converges exponentially to the constant equilibrium point. In fact, such a largeness restriction on μ χ 2 is actually necessary to some extent, since that the constant equilibrium point (1, 1, 0) is actually linearly unstable when such a condition is not satisfied. Subsequently, we turn our attention to the study of dynamic behavior of solutions. We introduce a time periodic external force to this system, and prove that the solution will gradually show the same periodic behavior under the action of periodic external force, and become a time periodic solution. At last, we analysis the stability and instability of equilibrium points, and discuss the influence of spatial diffusion, chemotaxis and haptotaxis effect on the stability of solutions. In particular, we find that only chemotaxis can change the stability of the solution and make the originally stable equilibrium (1, 1, 0) unstable, while the haptotactic term has no effect on the stability. [ABSTRACT FROM AUTHOR]

This proposed work investigates the performance of dc voltage of a three-phase Active Front-End (AFE) Sinusoidal Pulse Width Modulated (SPWM) rectifier during load switching. To obtain desired performances, a transfer function is derived in synchronous reference frame (dq), from which the gain of the PI controllers are estimated and observed the performance accordingly. In this research, the load current is feed-forwarded with d-axis current by a suitable choice of gain factor, which results a fractional feedback d-axis current control and improves the transient behaviour simultaneously. This will unalter the other performance parameters of the system such as, UPF operation, less Total Harmonic Distortion (THD) of input current, dc voltage boost etc. All the simulation results exhibits satisfactory performance and validated with a prototype developed using STM32F303RE microcontroller accordingly. [ABSTRACT FROM AUTHOR]

This paper focuses on the stability and decay rates of solutions to the three dimensional anisotropic magnetohydrodynamic equations with horizontal velocity dissipation and magnetic damping phenomenon. By fully exploiting the structure of the system, the energy methods and the method of bootstrapping argument, we prove the global stability of solutions to this system with initial data small in H 3 (R 3) . Furthermore, we make use of the integral representation approach to obtain the optimal decay rates of these global solutions and their derivatives. This result along with its proof offers an effective approach to the large-time behavior on partially dissipated systems and reveals the stabilizing phenomenon exhibited by electrically conducting fluids. [ABSTRACT FROM AUTHOR]

This study presents the interfacial behaviour of benzoylated cellulose of different wettability from melon and moringa pods waste using Pickering emulsions systems. The benzoylated cellulose was prepared in an aqueous alkaline medium using benzoyl chloride as a modifying agent and characterized by X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). The X-ray diffraction showed that crystallinity of cellulose from moringa and melon are 67.47 and 70.20%, respectively. The functionalized derivatives are thermally stable than the native counterpart. The SEM revealed that isolated cellulose suffered surface degradation upon functionalization as a result of the repeated collision between reactants. The wetting properties of the cellulose can be controlled by using different quantities of modifying agents, and the emulsions stability depend on the wettability of the emulsifiers. The higher stability recorded for the emulsions stabilized by benzoylated cellulose from moringa pod waste revealed that cellulose wettability depends on the sources. [ABSTRACT FROM AUTHOR]

In this study, we compared the repeatability and reproducibility of radiomic features obtained from positron emission tomography (PET) images according to the reconstruction algorithm used—advanced reconstruction algorithms, such as HYPER iterative (IT), HYPER deep learning reconstruction (DLR), and HYPER deep progressive reconstruction (DPR), or traditional Ordered Subset Expectation Maximization (OSEM)—to understand the potential variations and implications of using advanced reconstruction techniques in PET-based radiomics. We used a heterogeneous phantom with acrylic spherical beads (4- or 8-mm diameter) filled with 18F. PET images were acquired and reconstructed using OSEM, IT, DLR, and DPR. Original and wavelet radiomic features were calculated using SlicerRadiomics. Radiomic feature repeatability was assessed using the Coefficient of Variance (COV) and intraclass correlation coefficient (ICC), and inter-acquisition time reproducibility was assessed using the concordance correlation coefficient (CCC). For the 4- and 8-mm diameter beads phantom, the proportion of radiomic features with a COV < 10% was equivocal or higher for the advanced reconstruction algorithm than for OSEM. ICC indicated that advanced methods generally outperformed OSEM in repeatability, except for the original features of the 8-mm beads phantom. In the inter-acquisition time reproducibility analysis, the combinations of 3 and 5 min exhibited the highest reproducibility in both phantoms, with IT and DPR showing the highest proportion of radiomic features with CCC > 0.8. Advanced reconstruction methods provided enhanced stability of radiomic features compared with OSEM, suggesting their potential for optimal image reconstruction in PET-based radiomics, offering potential benefits in clinical diagnostics and prognostics. [ABSTRACT FROM AUTHOR]

In this article, the convective flow in a vertical layer subjected to a consistent magnetic field with nonzero gravity condition is investigated. One side of the vertical walls is heated, while the opposite side is cooling. The magnetic field strength, field orientation angle, magnetization effect, and thermal deviation of vertical walls play important roles as controlling parameters on the flow stabilization. The goal of this investigation is to analyze the flow characteristics and find out the significant distinction between water and kerosene based magnetic fluids under the variation of thermal and magnetic effects. The numerical results are obtained by the pseudo-spectral Chebyshev expansion method. The properties of all instability modes caused by three major mechanisms, namely; thermomagnetic, thermogravitational and magneto-gravitational are analyzed. In the normal magnetic field, the wave speed responds faster, and it is recognized by a relatively small wave number in water based fluid than that in kerosene based fluid. In oblique magnetic field, the waves propagate faster in both kerosene and water based fluids with the field inclination angle increases, but they still propagate slower in kerosene based fluid comparatively in water based fluid. According to the linear or non-linear magnetization law, both upward and downward propagating waves in kerosene based fluid propagate slower, and they are recognized by greater wave numbers than that in water based fluid. It is found that the basic flow in water based fluid is much more stable than in kerosene based fluid. [ABSTRACT FROM AUTHOR]

The aim of this paper is to establish the stability of pullback random attractors of non-autonomous fractional stochastic p-Laplacian equations driven by nonlinear colored noise. In order to overcome the difficulties caused by lack of compact Sobolev embedding on unbounded domains and weak dissipative structure of the equation, we first prove the existence, uniqueness and backward compactness of a special kind of pullback random attractor using the method of spectral decomposition in bounded domains and the uniform tail-estimates of solutions outside bounded domains over the infinite time interval. The measurability of this class of attractors is established by proving that the two classes of defined attractors are equal with respect to two different universes. Finally, the stability of the attractors is investigated by assuming that the time-dependent external forcing term converges to the time-independent external force as the time parameter tends to negative infinity. [ABSTRACT FROM AUTHOR]

The aim of this paper is to investigate the stability of a stationary solution of free boundary problems of the incompressible Navier–Stokes equations in a three-dimensional bounded domain with surface tension. More precisely, this article proves that if the initial angular momentum is sufficiently small and if the initial configuration is sufficiently close to equilibrium, then there exists a global classical solution that converges exponentially fast to a uniform rigid rotation of the liquid as t → ∞ with respect to a certain axis. The proof of the unique existence of a stationary solution is also given. [ABSTRACT FROM AUTHOR]

The impact of methanol concentration on direct methanol fuel cell (DMFC) of 45 cm2 zones of activity was experimentally studied with serpentine channel field design. The performance of the DMFC was analyzed and the optimum methanol concentration was determined with a polarization curve. A recently suggested Coefficient Diagram derived from PI Controller (CD-PIC) was used to run the model-based DMFC in a closed loop with the manipulated variable as methanol concentration. The CD-PIC design is simple and efficient compared to the Bode Diagram-based controller design. It is also used to test the performance and robustness of the system apart from the stability. A recently suggested PI Controller that relies on a Coefficient Schematic is employed in DMFC operation. The progress of the proposed CD-PIC is evaluated under load abandonment circumstances and set point monitoring. Set point tracking and load rejection tests are carried out with step changes at different operating points. The controller execution is evaluated in ways of controller progress measuring (CPM) indices. The suggested performance metrics for the proposed CD-PIC indicate that it yields better performance for servo problems and regulatory problems which support the supremacy of CD-PIC. The robustness of the CD-PIC is also analyzed. From the CPM indices, it is concluded that the recently created CD-PIC for DMFC is found as highly robust. [ABSTRACT FROM AUTHOR]

As an extension of Fuzzy C-Means (FCM), Evidence C-Means (ECM) is proposed in the framework of Dempster–Shafer theory (DST) and has been applied to many fields. However, the objective function of ECM involves only the distortion between the object and the prototype, which relies heavily on the initial prototype. Therefore, ECM may encounter the problem of local optimization. To solve this problem, this paper introduces ECM with Particle Swarm Optimization (PSO) initialization to determine the initial clustering centroids, and proposes Particle Swarm Optimization-based Evidential C-Means (PSO-ECM), which reduces the influence of bad initial prototypes and improves the local optimality problem of ECM. PSO-ECM is compared with three other clustering algorithms in four experiments and with ECM on a noise-containing dataset. According to the experimental results, PSO-ECM performs well in terms of different clustering validity metrics compared with existing clustering algorithms, has high stability of clustering, and can effectively and stably cluster noise-containing datasets and accurately identify outlier points. [ABSTRACT FROM AUTHOR]

The cross-border Krijtland region in Belgium and the Netherlands encloses hundreds of historical underground limestone quarries. The municipality of Riemst, Belgium, is used as a case study because of the high density of underground quarries found there, and which are prone to frequent collapses related to the historical underground exploitation. As not all underground quarries have been mapped, a mobile laser scanner has been employed to aid the mapping surveys. This paper investigates how this method and its data can be used in the field of geoheritage and safety studies of underground quarries. The mobile laser scanner is an effective tool in mapping the vast underground networks, as well as georeferencing and mapping underground voids that are inaccessible for normal surveyors using a total station. The large amount of data, obtained by various surveys provides a high level of detail in which different structures and features can be identified. The results demonstrate the presence of different typologies of entrances, gallery morphologies and outlines in various underground quarries. It also appears to be a valuable tool in visualizing and identifying geological and stability features, such as karst, pillar instability and collapse areas. It can be concluded that in the field of safety management and geoheritage studies a mobile laser scanner proves to be an efficient method for mapping, documenting the underground landscape and describing different structural elements of underground quarries. [ABSTRACT FROM AUTHOR]

We establish a convergence theorem for Crandall–Lions viscosity solutions to path-dependent Hamilton–Jacobi–Bellman PDEs. Our proof is based on a novel convergence theorem for dynamic sublinear expectations and the stochastic representation of viscosity solutions as value functions. [ABSTRACT FROM AUTHOR]

We study several discretizations of a second order gradient-like system with damping. We first consider an explicit scheme with a linear damping in finite dimension. We prove that every solution converges if the nonlinearity satisfies a global Lojasiewicz inequality. Convergence rates are also established. In the case of a strong nonlinear damping, we prove convergence of every solution for a fully implicit scheme in the one-dimensional case, even if the nonlinearity does not satisfy a Lojasiewicz inequality. The optimality of the damping is also established. Numerical simulations illustrate the theoretical results. [ABSTRACT FROM AUTHOR]

Mathematical modeling is considered as a method for studying the dynamics of grassland soil and plant systems in arid zones of Russia. The evolutionary development of grassland phytocenoses was modeled using the principles of nonequilibrium thermodynamics based on continuous and discrete mathematical formalisms. Examples are given, and problems of sustainable development of such systems under conditions of anthropogenic load and climate change are discussed. This study demonstrates new methodological capabilities of mathematical models of different types: in the form of systems of ordinary differential equations and discrete Markov chains. Prediction of degradation processes occurring in grasslands using these models has been studied in a comparative aspect. Differential models with constant and variable coefficients showed different results due to the nonlinearity of succession dynamics. The model with constant coefficients was refined by introducing time-dependent coefficients. The stability of the functioning of grassland ecosystems is discussed from the point of view of the formal parametric stability of solutions for a system of ordinary differential equations. Discrete modeling using the Markov chain technique showed that the degradation of soil and plant systems when the animal load is exceeded is described by a heterogeneous Markov process. Homogeneous Markov chains give adequate forecasts on one observation time interval. Prediction of the final states in the homogeneous approximation revealed that the observed nonlinearity in the dynamics of phytocenoses was caused by changes in the rate of development, ultimately leading to heterogeneity of the Markov chain. The issues of modeling nonlinear processes in the ecology of grassland soil and plant systems in the context of heterogeneous Markov processes are discussed. [ABSTRACT FROM AUTHOR]

This paper addresses the challenge of data-driven control of nonlinear systems, focusing on the limitations and capabilities of model reference Gaussian process regression (MR-GPR) and its evolved counterpart, model reference neural networks (MR-NN). MR-GPR, based on Gaussian processes renowned for their adaptability to diverse data structures, encounters scalability issues especially when handling large datasets. To address these limitations, this paper introduces MR-NN, an extension of MR-GPR, leveraging neural networks (NN) to manage large datasets and capture complex nonlinear dynamics effectively. We present a comprehensive evaluation of both methods through a classical control problem of the inverted pendulum, a system well-recognized for its nonlinear behavior. Numerical experiments are conducted to compare the methods in terms of control performance, computational efficiency, and reliability. [ABSTRACT FROM AUTHOR]

High order upwind summation-by-parts finite difference operators have recently been developed. When combined with the simultaneous approximation term method to impose boundary conditions, the method converges faster than using traditional summation-by-parts operators. We prove the convergence rate by the normal mode analysis for such methods for a class of hyperbolic partial differential equations. Our analysis shows that the penalty parameter for imposing boundary conditions affects the convergence rate for stable methods. In addition, to solve problems with discontinuous data, we extend the method to also have the weighted essentially nonoscillatory property. The overall method is stable, achieves high order accuracy for smooth problems, and is capable of solving problems with discontinuities. [ABSTRACT FROM AUTHOR]

Parental care is a behavioral strategy observed in many living organisms, where parents devote time and resources to ensuring their offspring's survival, growth, and well-being. Such care can be in various forms and involve different levels of investment, depending on the species and its ecological context. This study examines how parental care among prey contributes to the coexistence of prey and predator in an ecosystem. For this, we proposed a three-dimensional prey-predator system with the following factors–(i) stage structure and parental care in prey population, (ii) linear functional response for the interaction between immature prey and predators, whereas Holling type II functional response for the case of mature prey. We examined the conditions for the existence of equilibrium points, and their local and global stability for our proposed model. We observed the switching of stability of equilibria via transcritical bifurcation concerning the maturation rate and attack rate on adult prey. We examined all three possible existence scenarios for the maturation rate, e.g., extinction of both populations, prey-only existence, and coexistence of both prey and predator. We also investigated the appearance and disappearance of the limit cycle via Hopf-bifurcation concerning the predation rate and saturation constant of adult prey. We observed that parental care has a stabilizing effect on the system dynamics. Numerical simulations and graphical representations have been done to verify our theoretical findings. Sensitivity analysis is conducted to illustrate the importance of parental care in a stage-structure model. With the introduction of parental care parameter in prey species, we observe a more realistic dynamics of stage structured model. [ABSTRACT FROM AUTHOR]

The isolation vibration design for a self-synchronous vibrating system is challenging because the realization of the system's function depends on itself vibrating. We propose a method to solve the problem of vibrating isolation of the vibrating system, which is the realization of the self-balance function of the system from the perspective of self-synchronization. In the current study, a vibrating system with five rigid frames (RFs) driven by four vibrators is proposed to study its synchronization, stability, and self-balance characteristics. Utilizing the average method and Routh–Hurwitz stability criterion, the theoretical conditions of synchronization, stability, and self-balance of the system are obtained, respectively. Based on these three conditions, the stability and self-balance characteristics of the system in the different resonant regions are qualitatively analyzed in numeric, and the reasonable parameters matching principle of the system in realizing the synchronous stable operation with the function of self-balance is defined. A series of numerical simulations and experiments are further given to examine the correctness of the theoretical derivation and the rationality and practicability of the design of the mechanical system. The present work can be applied to the design of a new kind of vibrating machine, in which the working rigid frames can work with their circular motion trajectory, and the isolated rigid frame can remain stationary with around zero amplitude. [ABSTRACT FROM AUTHOR]

Soil conditioning is essential for addressing the stratum applicability problem of earth pressure balance (EPB) shields. Under high water pressures, EPB shields spew water and soil when excavating coarse-grained strata. Typically, foam combined with polymers and slurry is used to solve spewing. However, in current techniques, slurry, foam, and the other agents are mixed with soil separately, their synergistic effect is seldom realized. In this study, an anionic surfactant was used to foam in bentonite slurry to form bubble–slurry to maximize the synergy between bubbles and slurry. The slump, volume stability, and permeability test of bubble–slurry-conditioned sand was conducted to examine the conditioning effect, and the stratum applicability of bubble–slurry was determined from the perspective of permeability. It was found that the conditioning effect of bubble–slurry in coarse gravel soil was excellent and could expand the applicability of EPB shields. The main stabilization mechanism of bubble–slurry is that bentonite particles provide a space barrier for bubbles. And three seepage modes of bubble–slurry-conditioned sand were innovatively defined, and the occurrence conditions of the three seepage modes were analyzed according to the permeability coefficient of sand, initial dynamic shear force of bubble–slurry, and hydraulic gradient. [ABSTRACT FROM AUTHOR]

Lattice Kalman filter (LKF) is a nonlinear Kalman filter that utilizes a deterministic sampling method with the advantages of optional sampling points and a flexible balance between computational burden and estimation accuracy. However, the fixed angle of sampling points in LKF can limit the optimality of the selected points. To this end, this paper proposes a novel maximum correntropy square-root rotating lattice Kalman filter (MCSRLKF) to improve the performance of LKF by adjusting the angle of sampling points. In MCSRLKF, a rotation matrix is first constructed to enhance the estimation accuracy of LKF and the optimal rotation angle of sampling points is selected to generate rotating lattice Kalman filter (RLKF). Then, the square-root RLKF (SRLKF) is proposed to enhance the stability and estimation accuracy of RLKF. Due to the utilization of the minimum mean square error criterion in SRLKF, there is a potential for significant performance degradation in non-Gaussian noises. Thus, to enhance the robustness against non-Gaussian noises, the maximum correntropy criterion is applied to SRLKF, generating MCSRLKF. Moreover, the Cramér-Rao lower bound (CRLB) serves as an indicator for assessing the performance of MCSRLKF. Finally, simulations on the nonlinear function model and reentry vehicle tracking model are used to demonstrate that MCSRLKF exhibits excellent filtering accuracy and robustness when dealing with non-Gaussian noises. [ABSTRACT FROM AUTHOR]

The dynamic nature of multilingual families and their language policies has been touched upon by numerous studies. Adding to the field, the present study assesses the stability of family language policy in a standardised and quantitative manner. To this end, a linguistically heterogenous sample consisting of 488 multilingual families raising young children in Belgium's Flemish Community was surveyed twice, eighteen months apart. Based on the collected longitudinal survey data, the present study offers statistically verifiable evidence for the (partially) dynamic character of family language policy. Firstly, parental beliefs in a multilingual advantage were strengthened and a change was found in language-specific beliefs regarding children's language acquisition. Secondly, the families' practices demonstrate a shift towards the Dutch institutional language, particularly in parental language use when communicating with each other and with their child, and in the child's overall exposure. The observed shift in practices and beliefs underscores not only parents' continuous assessment of their children's linguistic needs and development, but also the societal environment influencing this assessment and adjustment. However, while significant changes in language beliefs and practices were uncovered, the more conscious and explicit component of language management proved stable across time, corroborating the independent character of the three family language policy components. [ABSTRACT FROM AUTHOR]

The main object of the present paper is the study of thermoelastic laminated beam with structural damping, where the heat conduction is given by the classical Fourier's law and acting on both the rotation angle and the transverse displacements. We establish an exponential stability result for the considered problem in case of equal wave speeds. In the opposite case, we show the lack of exponential stability. Furthermore, a polynomial stability result is established. [ABSTRACT FROM AUTHOR]

Maize is an important staple crop in Ethiopia, but there is a limited number of pro-vitamin A (PVA) and quality protein maize (QPM) varieties under commercial production compared with normal maize varieties in the country. Therefore, developing nutritionally enriched maize varieties is helpful to mitigate malnutrition problems among communities whose diets are more dominated with maize. This study was carried out to determine genotype by environment (G × E) interaction and grain yield stability of introduced and locally developed PVA and QPM hybrids and identify promising hybrids for further evaluation to promote release. Forty-four hybrids, including 20 PVA and 18 QPM hybrids with six checks (One PVA, two QPM, three normal maize) were evaluated using a row-column design (22-rows and six columns) with three replications at six locations in Ethiopia in 2022. The effects of genotype, environment and G × E interaction were highly significant for grain yield. Based on additive main effects and multiplicative interaction (AMMI), genotype plus genotype by environment (GGE) biplot analysis and yield stability index (YSI), the most stable PVA and QPM hybrids were identified, but none of them had high or comparable grain yield potential compared with normal checks. Among top ten hybrids, entry 15 (3XM2100055) was the highest yielding QPM hybrid which had comparable yield performance with the best normal maize checks (BH549 and BH546) and out yielded to QPM (BQPY545 and BHQP548) and PVA (BHA5211) checks, and this hybrid was well adapted to ArsiNegele, Bako and Jima environments. The GGE analysis delineated the six testing environments into three mega environments. Ambo and ArsiNegele were the most discriminating and representative environments therefore, these environments are the most suitable to select genetically well adapted PVA and QPM hybrids. [ABSTRACT FROM AUTHOR]

In this paper, we propose an error analysis of fully decoupled time-discrete scheme for the Cahn–Hilliard-MHD (CHMHD) diffuse interface model. Firstly, we use the "zero-energy-contribution" technique to reconstruct the system by introducing three scalar auxiliary variables (SAV). Secondly, we construct first-order semi-discrete SAV scheme for this new system by using pressure-correction method, and we also demonstrate its unconditional stability in energy. Then, we give a detailed implementation procedure to show that the proposed scheme is linear and fully decoupled, and only a series of elliptic equations with constant coefficients need to be solved at each time step. Moreover, we establish the optimal convergence rate by rigorous error analysis. Finally, we present numerical experiments to validate the accuracy, stability and efficiency of the proposed scheme. [ABSTRACT FROM AUTHOR]

In this article, we first convert a second order singularly perturbed boundary value problem (SPBVP) into a pair of initial value problems, which are solved later using exponential time differencing (ETD) Runge–Kutta methods. The stability analysis of the proposed scheme is addressed. Some linear and non-linear problems have been solved to study the applicability of the proposed method. [ABSTRACT FROM AUTHOR]

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In the present article, the Hyers–Ulam stability of the following inequality is analyzed: 0.1 { d (f (ı + ȷ) , (f (ı) + f (ȷ))) ≤ d (ρ 1 ((f (ı + ȷ) + f (ı − ȷ) , 2 f (ı))) d (f (ı + ȷ) , (f (ı) + f (ȷ))) ≤ + d (ρ 2 (2 f (ı + ȷ 2) , (f (ı) + f (ȷ)))) in the setting of digital metric space, where ρ 1 and ρ 2 are fixed nonzero complex numbers with 1 > 2 | ρ 1 | + | ρ 2 | by using fixed point and direct approach. [ABSTRACT FROM AUTHOR]

The way the topological structure transforms from a decoupled to a coupled state in multiplex networks has been extensively studied through both analytical and numerical approaches, often utilizing models of artificial networks. These studies typically assume uniform interconnections between layers to simplify the analytical treatment of structural properties in multiplex networks. However, this assumption is not applicable for real networks, where the heterogeneity of link weights is an intrinsic characteristic. Therefore, in this paper, link weights are calculated considering the node's reputation and the impact of the inter-layer link weights are assessed on the overall network's structural characteristics. These characteristics include synchronization time, stability of synchronization, and the second-smallest eigenvalue of the Laplacian matrix (algebraic connectivity). Our findings reveal that the perturbation in link weights (intra-layer) causes a transition in the algebraic connectivity whereas variation in inter-layer link weights has a significant impact on the synchronization stability and synchronization time in the multiplex networks. This analysis is different from the predictions made under the assumption of equal inter-layer link weights. [ABSTRACT FROM AUTHOR]

Bispecific antibodies (bsAbs) hold promises for enhanced therapeutic potential surpassing that of their parental monoclonal antibodies. However, bsAbs pose great challenges in their manufacturing, and one of the common reasons is their susceptibility to aggregation. Building on previous studies demonstrating the functionality and potential manufacturability of Fab-scFv format bsAb, this investigation delved into the impact of environmental factors—such as pH, buffer types, ionic strength, protein concentrations, and temperatures—on its stability and the reversal of its self-associated aggregates. Mildly acidic, low-salt conditions were found optimal, ensuring bsAb stability for 30 days even at elevated temperature of 40 °C. Furthermore, these conditions facilitated the reversal of its self-associated aggregates to monomers during the initial 7-day incubation period. Our findings underscore the robustness and resilience of Fab-scFv format bsAb, further confirming its potential manufacturability despite its current absence as commercial products. [ABSTRACT FROM AUTHOR]

A nonlinear parabolic equation with transformation of the spatial variable and periodic conditions on the circle is considered. Using the method of separation of variables, we obtain properties of eigenfunctions and eigenvalues of the corresponding linearized problem. Using the method of central manifolds, we prove the existence and stability of spatially inhomogeneous stationary solutions. Based on the Galerkin method, we analyze approximate solutions of the original problem. [ABSTRACT FROM AUTHOR]

We consider the problem of stability of nonzero integral manifolds of a nonlinear finitedimensional system of ordinary differential equations whose right-hand side is a periodic vector-valued function of the independent variable containing a parameter. We assume that the system has a trivial integral manifold for all values of the parameter and the corresponding linear subsystem does not possess the property of exponential dichotomy. The aim of this work is to find sufficient conditions for stability, instability, and asymptotic stability of a local nonzero integral manifold. For this purpose, we use the method of Lyapunov functions modified to the problem considered and singularities of the right-hand sides of the system. [ABSTRACT FROM AUTHOR]

In this work, we study a nonlocal erosion equation, which simulates the process of nanorelief formation. For a periodic boundary-value problem for the functional differential equation with partial derivatives, we examine local bifurcations in the cases where homogeneous equilibrium states change their stability. We prove that in the problem considered, subcritical bifurcations occur. [ABSTRACT FROM AUTHOR]