Values Of Parameters Research Articles

Projecting COVID-19 intensive care admissions for policy advice, the Netherlands, February 2020 to January 2021.

BackgroundModel projections of coronavirus disease 2019 (COVID-19) incidence help policymakers about decisions to implement or lift control measures. During the pandemic, policymakers in the Netherlands were informed on a weekly basis with short-term projections of COVID-19 intensive care unit (ICU) admissions.AimWe aimed at developing a model on ICU admissions and updating a procedure for informing policymakers.MethodThe projections were produced using an age-structured transmission model. A consistent, incremental update procedure integrating all new surveillance and hospital data was conducted weekly. First, up-to-date estimates for most parameter values were obtained through re-analysis of all data sources. Then, estimates were made for changes in the age-specific contact rates in response to policy changes. Finally, a piecewise constant transmission rate was estimated by fitting the model to reported daily ICU admissions, with a changepoint analysis guided by Akaike's Information Criterion.ResultsThe model and update procedure allowed us to make weekly projections. Most 3-week prediction intervals were accurate in covering the later observed numbers of ICU admissions. When projections were too high in March and August 2020 or too low in November 2020, the estimated effectiveness of the policy changes was adequately adapted in the changepoint analysis based on the natural accumulation of incoming data.ConclusionThe model incorporates basic epidemiological principles and most model parameters were estimated per data source. Therefore, it had potential to be adapted to a more complex epidemiological situation with the rise of new variants and the start of vaccination.

Optimization of surface roughness in milling of EN 24 steel with WC-Coated inserts using response surface methodology: analysis using surface integrity microstructural characterizations

Introduction: Among alloys of medium-carbon and high-strength steel, EN 24 steel is characterised by its nickel-chromium-molybdenum composition. EN 24 steel is highly suitable for application in heavy-duty projects due to its notable resilience to damage, especially when exposed to low temperatures. With the objective of minimising surface irregularities, this research endeavours to enhance the milling process of EN 24 steel by employing coated tungsten carbide (WC) tool inserts.Methods: Feed rate, cutting speed, depth of cut, and cutting fluid are all crucial process factors in the experimental investigation. Four distinct levels are applied to each factor. The research utilises the Design of Experiments (DOE)-based Central Composite Design of Response Surface Methodology. To predict output parameters, mathematical models are developed utilising analysis of variance (ANOVA) for optimisation purposes.Results and discussions: Through the utilisation of multi-objective optimisation, the optimal combination for tungsten carbide inserts was determined, which provided surface irregularities of 0.301 µm. Cutting speed (CS) of 149.507 m/min, feed rate (FR) of 340.27 mm/min, depth of cut (DOC) of 0.599 mm, and cutting fluid (CF) of 12.50 L/min are the optimal parameters. The surface morphologies of the machined workpiece at particular parameter values can be discerned through scanning electron microscope (SEM) analysis, yielding significant insights. The optimal parameters that have been identified provide practical recommendations for improving the milling method of EN 24 steel when tungsten carbide inserts are utilised. Understanding the milling process in its entirety is facilitated by SEM analysis of surface morphologies and microstructures under particular cutting conditions. The morphology and surface irregularities of the machined workpiece are evaluated using profilometry, which provides additional insight into surface integrity. The discourse investigates the potential applications and implications of the results, as well as suggests directions for further study concerning the enhancement of milling processes for similar steel alloys.

Monte Carlo Investigation of Dielectric Characteristics in Silicene–Germanene Nanosystem with Junction Connection

In this study, Monte Carlo investigation delves into the dielectric features of silicene–germanene nanosystem with junction connection. We emphasized the profound influence of physical parameters, coupling between Si–Si and Ge–Ge atoms and temperature, on these dielectric features. Our results highlight the pivotal role of the coupling parameter between Ge atoms in influencing blocking temperatures, underlining the significance of high values for spin and coupling parameters for achieving a high blocking temperature and delaying transitions. Furthermore, our analysis of electric hysteresis loops demonstrates their sensitivity to parameter variations, which can offer valuable insights for nanoelectronics and materials science applications.

Constitutive Modeling of Mouse Arteries Suggests Changes in Directional Coupling and Extracellular Matrix Remodeling That Depend on Artery Type, Age, Sex, and Elastin Amounts.

Arterial stiffening occurs during natural aging, is associated with an increased risk of adverse cardiovascular events, and can follow different timelines in males and females. One mechanism of arterial stiffening includes remodeling of the extracellular matrix (ECM), which alters the wall material properties. We used elastin haploinsufficient (Eln+/-) and wildtype (Eln+/+) mice to investigate how material properties of two different arteries (ascending aorta and carotid artery) change with age, sex, and ECM composition. We used a constitutive model by Dong and Sun that is based on the Holzapfel-Gasser-Ogden (HGO) type, but does not require a discrete number of fibrous ECM families and allows varied deformation coupling. We find that the amount of deformation coupling for the best fit model depends on the artery type. We also find that remodeling to maintain homeostatic (i.e., young, wildtype) values of biomechanical parameters with age, sex, and ECM composition depends on the artery type, with ascending aorta being more adaptable than carotid artery. Fitted material constants indicate sex-dependent remodeling that may be important for determining the time course of arterial stiffening in males and females. We correlated fitted material constants with ECM composition measured by biochemical (ascending aorta) or histological (carotid artery) methods. We show significant correlations between ECM composition and material parameters for the mean values for each group, with biochemical measurements correlating more strongly than histological measurements. Understanding how arterial stiffening depends on age, sex, ECM composition, and artery type may help design effective, personalized clinical treatment strategies.

Numerical simulation for radiative hybrid nanofluid (TiO2+Fe3O4∕H2O) flow due to a non-uniform stretching sheet with variable permeability

Variable permeability plays a crucial role in various manufacturing and technical applications such as fixed-bed catalytic reactors, heat exchangers, and dying, among others. The primary focus of this paper is to investigate the impacts of variable permeability on hybrid nanofluid (HNF) flow due to nonlinear sheet stretching with thermal heat flux. The HNF is made up of a mixer of [Formula: see text] and [Formula: see text] nanoparticles and water serving as the base fluid. Using efficient similarity transformations, the flow-governing equations are converted into a set of ordinary differential equations, and the resulting system is computationally solved by using the MATLAB program (bvp4c). The impact of various physical variables on the fluid velocity and heat transfer characteristics is analyzed via graphs. It is found that as the permeability parameter rises, the velocity of the HNF diminishes while the temperature amplifies. The drag force coefficient declines with an intensification of the volume fraction of the [Formula: see text] nanoparticles. The HNF [Formula: see text] exhibits 0.45–0.75% increase in heat transfer rate when compared to a nanofluid [Formula: see text] for different values of heat source parameter. The current investigation is compared to the existing literature, revealing a good level of agreement.

Water disinfection using hydrogen peroxide with fixed bed hematite catalyst - kinetic and activity studies.

A lab-scale reactor with a fixed-bed hematite catalyst for the effective decomposition of H2O2 and bacteria inactivation was designed. The bactericidal effect is the largest at a low initial bacterial count of 2·103CFU/L, which is typical for natural surface waters. When using a 5mM H2O2 solution and a residence time of 104min, the reduction in the number of E. coli bacteria is about 3.5-log. At a higher initial bacterial count of 1-2·104CFU/L, a 5mM H2O2 solution reduces the bacteria number by about 4-log. The H2O2 decomposition follows the log-linear kinetics of a first-order reaction while the bacterial inactivation does not. The kinetics of bacterial inactivation was described using the Weibull model in the modified form: log10(N0/N) =b · tn. The values of the non-linearity parameter n were found to be lower than 1, indicating that bacterial inactivation slows down over time. With increasing initial H2O2 concentration, the rate parameter b increases while the non-linearity parameter n decreases. With increasing temperature, both parameters increase. The stability of the catalyst has been proved by XRD, FTIR, SEM, and ICP-OES. The concentration of iron leaching into water during disinfection is much lower than the limit declared by WHO for iron in drinking water. The results show that technical-grade hematite is a promising Fenton-like catalyst for water disinfection. The fixed-bed reactor can be the basis of the mobile installations for water purification in emergencies.

Cost-effectiveness analysis of minimally invasive surgical treatments for benign prostatic hyperplasia: implications for Japan’s public healthcare system

Aims Benign prostatic hyperplasia (BPH) represents a significant public health issue in Japan. This study evaluated the lifetime cost-effectiveness of water vapor energy therapy (WAVE) versus prostatic urethral lift (PUL) for men with moderate-to-severe BPH from a public healthcare payer’s perspective in Japan. Materials and methods A decision analytic model compared WAVE to PUL among males in Japan. Clinical effectiveness and adverse event (AE) inputs were obtained from a systematic literature review. Resource utilization and cost inputs were derived from the Medical Data Vision database and medical service fee national data in Japan. Experts reviewed and validated model input parameters. One-way and probabilistic sensitivity analyses were conducted to determine how changes in the values of uncertain parameters affect the model results. Results Throughout patients’ lifetimes, WAVE was associated with higher quality-adjusted life years (0.920 vs. 0.911 year 1; 15.564 vs. 15.388 lifetime) and lower total costs (¥734,134 vs. ¥888,110 year 1; ¥961,595 vs. ¥1,429,458 lifetime) compared to PUL, indicating that WAVE is a more effective and less costly (i.e. dominant) treatment strategy across all time horizons. Lifetime cost-savings for the Japanese healthcare system per patient treated with WAVE instead of PUL were ¥467,863. The 32.7% cost difference between WAVE and PUL was predominantly driven by lower WAVE surgical retreatment rates (4.9% vs. 19.2% for WAVE vs PUL, respectively, at 5 years) and AE rates (hematuria 11.8% vs. 25.7%, dysuria 16.9% vs. 34.3%, pelvic pain 2.9% vs. 17.9%, and urinary incontinence 0.4% vs. 1.3% for WAVE vs PUL, respectively, at 3 months). Model findings were robust to changes in parameter input values. Limitations The model represents a simplification of complex factors involved in resource allocation decision-making. Conclusions Driven by lower retreatment and AE rates, WAVE was a cost-effective and cost-saving treatment for moderate-to-severe BPH in Japan compared to PUL, providing better outcomes at lower costs to the healthcare system.

Efficiency of the non-maximally entangled quantum Otto engine

We generalized the maximally entangled Hamiltonian of the isotropic Heisenberg XX model with two spin-1/2 particles to the case of non-maximal entanglement parametrized by the degree of non-maximality 0 < n < 1. The thermal concurrence as the function of the degree of non-maximality in the entanglement at different values of the exchange parameter is calculated. We analyzed the efficiency of the quantum Otto engine for different scenarios of exchange parameter regimes and the degree of maximal entanglement between the spin states. We showed that it is possible to run the quantum Otto engine using non-maximally entangled states and achieve higher efficiencies by controlling the exchange parameter value with respect to a critical value J c and this feature also depends on the degree of non-maximal entanglement n ≠ 1. This result may be useful for harnessing the non-maximal entanglement in quantum heat engine for optimizing the operation of quantum devices interacting with heat bath or environment.

CPV System Optical Performance Evaluation by Means of Direct Experimental Measurement Procedure

The optics is the component that most affects the concentrating photovoltaic (CPV) system performance, depending above all on the concentration factor and optical efficiency. Hence, a basic aspect is the concentrated solar flux measure on the receiving area, the evaluation of which is principally realized by indirect measurement methods. First, a literature review on indirect and direct methods used for the evaluation of concentrated solar flux and optical parameters is presented in this paper. The experimental measurement procedure, which is able to evaluate the optical parameters and concentrated solar flux in CPV systems, is also presented. The main steps of this procedure are represented by experimental system setup, sensor selection for concentrated solar flux estimation, identification of all the factors affecting optical performances, and development of an experimental campaign and output analysis. In particular, the optical characterization results of a CPV system are obtained by means of in-depth experimental analysis using Triple-Junction (TJ) solar cells with areas of 5.5 × 5.5 mm2 and 10 × 10 mm2. Three different setups have been analyzed related to primary and secondary optics composition. The main aim of this paper is the determination of a direct measuring technique, rarely adopted in literature in comparison to the established techniques, that is able to evaluate experimentally the optical parameter values and that can be standardized for other CPV systems. In particular, equations that link the optical concentration factor (C) and efficiency (ηopt) with focal distance (h) represent the fundamental results. They can be used for similar point-focus configurations presenting the same TJ cell size and ranges of C, ηopt and h. Finally, the experimental results of the direct method are compared with those of an indirect method adopting the same CPV system and operational conditions.

Adaptability of Buckwheat in vitro

The research goal was to study the morphogenesis of common buckwheat plantlets obtained using different stressors in vitro. The research object was common buckwheat variety Izumrud – single-node cuttings (1.0-1.5 cm in length; two-three lowest internodes) of the plantlets that were obtained by subculturing on a hormone-free MS medium and of the lines that showed tolerance to CuSO4 Å~ 5H2O (161 and 184 mg/l) at the Laboratory of Agricultural Biotechnology. Selective media were prepared based on the Murashige and Skoog medium supplemented with a zinc salt (ZnSO4 Å~ 7H2O) at concentrations of 808, 909, 1010, 1111, 1212, and 1313 mg/l. To evaluate the morphological characteristics of the studied genotypes, their parameter values were calculated relative to the control and expressed as percentage. The genotypes were compared in the following groups depending on the exposure to a certain stressor: group 1 – the genotypes obtained without exposure to copper, group 2 – the genotypes obtained on the media containing the copper salt at a concentration of 161 mg/l, and group 3 – the genotypes obtained on the media containing the copper salt at a concentration of 184 mg/l. Plants from different groups demonstrated dissimilar growth rates under the toxic conditions caused by the studied concentrations of zinc. The morphological parameter values of the copper-tolerant plants (groups 2 and 3) were significantly higher than those of the plantlets obtained without exposure to copper. The plantlets tolerant to CuSO4 Å~ 5H2O (161 and 184 mg/l) showed a heightened resistance to the selective factor (Zn) as evidenced by their high regeneration and survival rates (95.7-100%).

Screening and evaluation of bacterial endophytes of cowpea [Vigna unguiculata (L.) Walp.] for plant growth promotion and biocontrol potential

Cowpea [Vigna unguiculata (L.) Walp], is a popular leguminous vegetable crop grown in the wetland fallows of Kerala, India. Web blight caused by Rhizoctonia solani has turned out to be a problem in cowpeas, leading to substantial yield loss. We isolated 22 endophytic bacteria from fodder cowpea var. Aiswarya and 16 from bush cowpea var. Bhagyalakshmi, and evaluated their plant growth promotion ability and potential for web blight pathogen suppression. Initially, the isolates were screened in vitro for their plant growth promotional traits and antagonism against R. solani. The potential isolates were identified as Bacillus subtilis, B. amyloliquefaciens and B. velezensis through 16S rDNA cataloguing. Plant growth-promoting traits like the production of IAA (Indole acetic acid), ammonia, phosphorus, and siderophore by the promising isolates were also investigated. B. amyloliquefaciens CBSE5 recorded the highest IAA (3.54 microgram/mL) and siderophore production. B. velezensis CBRE5 showed the highest ammonia (177.29 micro moles/mL) production and phosphate solubilization. In the in vivo assay, seed biopriming along with foliar application on 20 and 40 days after sowing, of a consortium of B. amyloliquefaciens CBSE5 and B. velezensis CBRE5 recorded maximum values for all growth parameters viz. shoot length, root length, shoot fresh weight, root fresh weight, shoot dry weight, root dry weight, pod yield and number of pods per plant. The present study reports for the first time the use of endophytic Bacillus spp. isolated from cowpeas as plant growth-promoting bacteria, with biocontrol potential against the web blight pathogen R. solani.

Control Charts for Exponentially Distributed Characteristics: SD, ED, ESD with Taguchi’s Loss Function

ABSTRACT This paper addresses the challenge of quality characteristics that follow an exponential distribution, which can significantly impact decision-making in various fields. Existing approaches rely on approximations to convert exponential distributions to normal distributions, upon which control charts are constructed. However, such conversions introduce errors that can lead to incorrect outcomes, particularly for highly sensitive characteristics. To address this limitation, we propose the development of control charts specifically designed for exponential characteristics, without relying on approximations. Our objective is to introduce four different schemes for constructing these control charts: a statistical scheme, an economic scheme, an economic-statistical scheme combined with Taguchi’s loss function, and an economic-statistical scheme without the application of a loss function. To determine optimal design parameter values for each scheme, we employ the artificial bee colony algorithm. Additionally, we conduct a sensitivity analysis to investigate the impact of design parameters on each proposed design. To illustrate the practical implementation of these control charts, we provide a numerical example that demonstrates their effectiveness. By addressing the limitations of existing approaches and offering novel control chart designs, this paper contributes to enhancing decision-making accuracy and reliability in scenarios involving exponentially distributed quality characteristics.

Dynamical study and diverse soliton collisions for the Kraenkel–Manna–Merle system in ferrites

We investigate the rational solitons of the Kraenkel–Manna–Merle (KMM) system in ferrites via symbolic computation with the ansatz functions technique and logarithmic transformation. The KMM system describes the propagations of the ferromagnetic particles in ferrite materials. Multiwave solitons are reported by using the three-wave technique. Homocentric breathers (HBs) approach is also applied to build new forms of exact solutions. We construct M-shaped solitons and their dynamics are shown via the appropriate values of parameters. Two types of interactions for rational soliton with kink wave are investigated. Additionally, kink cross-rational solitons (KCRSs) and periodic cross-rational solitons (PCRSs) are examined via suitable transformation.

The sensitivity demonstration and propagation of hyper-geometric soliton waves in plasma physics of Kairat-II equation

This study investigates the Kairat-II equation, describing optical pulse behavior in optical fibers and plasma. To uncover new solitary wave profiles, the study employs an extended direct algebraic method. This kind of solution has never been reached in research prior to this study. This innovative approach efficiently encompasses a comprehensive set of thirty-seven solitonic wave profiles, spanning various soliton families. The investigation unveils novel solitonic wave patterns, including plane solutions, hyper-geometric solutions, mixed hyperbolic solutions, periodic and mixed periodic solutions, mixed trigonometric solutions, trigonometric solutions, shock solutions, mixed shock singular solutions, mixed singular solutions, complex solitary shock solutions, singular solutions, and shock wave solutions. To demonstrate the pulse propagation characteristics, the research presents 2-D, 3-D, and contour graphics based on parameter values, aiding in a better understanding of the phenomenon.

Applicability of electromyography (EMG) as a prospective technique for textural evaluation of different types of biscuits

Bakery industry is an important segment of the food industry, worldwide, and texture is an important determinant in the consumer acceptability of baked products especially biscuits. In this study, six different textured biscuits namely, whole wheat flour biscuit, chocolate biscuit, cumin biscuit, cardamom biscuit, pistachio biscuit and cashew biscuit, procured from local bakery, were analyzed for their proximate composition and color characteristics. The biscuits were having significantly (p ≤ 0.05) different values for proximate composition and color parameters. This study primarily aimed at investigating the application of electromyography (EMG) as a prospective technique for texture evaluation of these different types of biscuits. EMG is an upcoming technique for in vivo food texture evaluation which gives real-time information about the dynamic textural changes occurring during mastication of a food product. The EMG study was conducted on ten human subjects who were served six samples of biscuits in duplicate. To eliminate subject factor variance, two-way ANOVA was applied on the relative values of EMG variables. Two recordings of same subject in an EMG session for a biscuit sample showed significant (p ≤ 0.05) degree of similarity indicating that human mastication behavior is reproducible. Initially, twenty-eight EMG parameters were obtained which were reduced to five representative parameters using cluster analysis. Principal component analysis further classified these five masticatory parameters into two independent principal components (PC1 and PC2) for explaining the data variance. Cumulative proportions for PC1 and PC2 were 37.6% and 70.8%, respectively. The results showed that mastication time obtained from electromyographic analysis can evaluate sensory fracturability, hardness and chewiness. While middle interburst duration can effectively evaluate sensory cohesiveness and instrumental flexural strength. The study concluded that EMG can serve as a comprehensive texture evaluation tool in the bakery industry.

Optimization and comprehensive evaluation of liquid cooling tank for single-phase immersion cooling data center

Single-phase immersion cooling has emerged as a highly promising solution for addressing energy challenges and the substantial heat dissipation demands in data centers (DCs). The liquid cooling tank is a curial component in such system where numerous servers are immersed and the coolant are evenly flowed to each server. However, its performance and the comprehensive evaluation for the tank have not received much attention. In this study, by using the validated numerical model, the different tank structures, with or without consideration of baffle and porous panel, were firstly discussed. Then, four key parameters of tank, including inlet flowrate (Parameter A), the ratio of separation chamber height to server height (Parameter B), the ratio of pressure chamber height to server height (Parameter C), and the porosity of the porous panel (Parameter D) were explored in detail. Finally, the tank performance is evaluated and optimized by the orthogonal analysis and the entropy weight method (EWM). Results showed that, flow uniformity within the tank can be enhanced by incorporating a porous panel, and it was advisable to minimize the gaps between servers, despite the potential increase in pressure loss. Parameter A significantly impacted both the maximum temperature and pressure loss. Parameters B and C demonstrated effects on coolant weight and pressure loss, while Parameter D influenced pressure loss. By using orthogonal analysis and the EWM, maximum temperature carried the highest weight (0.362), followed by temperature difference (0.245), coolant weight (0.216), and pressure loss (0.177). The recommended values for Parameters A-D were 4 m3/h, 1.35 %, 4.05 %, and 11.33 %, respectively, which could be also considered as universality, since the comprehensive evaluation index only changed by 8 % when the server number increased from 10 to 40.

Investigation of soliton solutions to the Peyrard-Bishop-Deoxyribo-Nucleic-Acid dynamic model with beta-derivative

This study purposes to extract some fractional analytical solutions of the Peyrard-Bishop-Deoxyribo-Nucleic-Acid ([Formula: see text]-PBDNA) dynamic model with the beta-derivative by the unified Riccati equation expansion method (UREEM). Furthermore, we examine the role of various parameters of the fractional model on the soliton dynamic. The research focuses on computational biophysics and materials science, examining the impact of various parameters on the fractional model. This paper contributes to understanding soliton solutions and the [Formula: see text]-PBDNA dynamic model, demonstrating the applicability of the UREEM method to various fractional models. Some soliton solutions of the model are successfully generated by applying the UREEM. Implementing the UREEM, we take a fractional wave transformation to convert the model into a nonlinear ordinary differential equation. So, a linear equation system is generated. After the system is solved, the soliton solutions are gained for the appropriate solution sets. Finally, 3D, 2D and contour graphs of diverse solutions are depicted at suitable values of parameters. In addition, this paper presents 3D, 2D and contour graphs of various solutions with suitable parameter values. The results are beneficial for interpreting the model in future work and confirm that UREEM is effectively applicable to diverse fractional models, coupled with a comprehensive graphical analysis of how different parameters influence these solutions.

Cost-effectiveness of sodium zirconium cyclosilicate for advanced chronic kidney patients in Singapore.

Hyperkalaemia (HK) is prevalent among patients with chronic kidney disease (CKD) and chronic heart failure, especially if they are treated with renin-angiotensin-aldosterone system inhibitors (RAASi). This study evaluated the cost-effectiveness of a newly developed anti-HK therapy, sodium zirconium cyclosilicate (SZC), to the current standard of care for treating HK in advanced CKD patients from the Singapore health system perspective. We adapted a global microsimulation model to simulate individual patients' potassium level trajectories with baseline potassium ≥5.5 mmol/L, CKD progression, changes in treatment, and other fatal and non-fatal events. Effectiveness data was derived from ZS-004 and ZS-005 trials. Model parameters were localised using CKD patients' administrative and medical records at the Singapore General Hospital Department of Renal Medicine. We estimated the lifetime cost and quality-adjusted life years (QALYs) of each HK treatment, and the incremental cost-effectiveness ratio of SZC. SZC demonstrated cost-effectiveness with an incremental cost-effectiveness ratsio of SGD 45 068 per QALY over a lifetime horizon, below the willingness-to-pay threshold of SGD 90 000 per QALY. Notably, SZC proved most cost-effective for patients with less severe CKD who were concurrently using RAASi. Sensitivity analyses confirmed the robustness of the findings, accounting for alternative parameter values and statistical uncertainty. This study establishes the cost-effectiveness of SZC as a treatment for HK, highlighting its potential to mitigate the risk of hyperkalaemia and optimise RAASi therapy. These findings emphasise the value of integrating SZC into the Singapore health system for improved patient outcomes and resource allocation.

Effects of MHD and thermal radiation on non-Newtonian fluid with Cattaneo–Christov heat over a stretching flow surface

In this study, we are investigating the flow of an incompressible Williamson fluid using a Cattaneo–Christov heat flux model, with consideration for a magnetic Reynolds number that is not high. This fluid flows over a linearly stretched 2-D surface and is affected by a magnetic field, thermal radiation-diffusion, and heat generation. To model the Williamson flow, we apply a boundary layer approximation and develop the ordinary differential equations. The system of differential equations is transformed into a system of ordinary differential equations using a suitable transformation. We utilize the Iterative Runge–Kutta fourth-order scheme to numerically solve the boundary conditions associated with the nonlinear, dimensionless ordinary differential equations. Graphical representations of the results are employed to analyze the impact of physical properties on velocity, temperature, and concentration, with the numerical results presented in tabular form. Upon comparing our findings with previously published results, we have found them to be in good agreement. The velocity decreases as the Williamson fluid factor gradually increases. Williamson fluids are recognized for their shear thinning behavior, wherein viscosity decreases as the shear rate increases. However, higher parameter values can lead to increased fluid viscosity, potentially reducing the degree of shear thinning. This phenomenon results in a more uniform viscosity profile across varying shear rates, contributing to a reduced velocity distribution within the fluid.

An Improved Sparrow Search Algorithm for the Optimization of Variational Modal Decomposition Parameters

Variational modal decomposition (VMD) is frequently employed for both signal decomposition and extracting features; however, the decomposition outcome is influenced by the quantity of intrinsic modal functions (IMFs) and the specific parameter values of penalty factors. To tackle this issue, we propose an algorithm based on the Halton sequence and the Laplace crossover operator for the sparrow search algorithm–VMD (HLSSA-VMD) to fine-tune the parameters of VMD. First, the population initialization by the Halton sequence yields higher-quality initial solutions, which effectively addresses the issue of the algorithm’s sluggish convergence due to overlapping and the lack of diversity of the initial solutions. Second, the introduction of the Laplace crossover operator (LX) to perturb the position of the best individual in each iteration helps to prevent the algorithm from becoming ensnared in a local optimum and improves the convergence speed of the algorithm. Finally, from the simulation of 17 benchmark test functions, we found that the HLSSA exhibited superior convergence accuracy and accelerated convergence pace, as well as better robustness than the particle swarm optimization (PSO) algorithm, the whale optimization algorithm (WOA), the multiverse optimization (MVO) algorithm, and the traditional sparrow search algorithm (SSA). In addition, we verified the effectiveness of the HLSSA-VMD algorithm on two simulated signals and compared it with PSO-VMD, WOA-VMD, MVO-VMD, and SSA-VMD. The experimental findings indicate that the HLSSA-VMD obtains better parameters, confirming the superiority of the algorithm.