The laminar movement in an expanding and contracting permeable pipe or surface has recently attracted the attention of many scholars owing to its application in engineering and biological processes. The objective of the current study is to examine the influence of chemical processes on magnetized nanofluid flow over extending or shrinking permeable pipes with a heat reservoir. The flow equations are renovated into first ODEs by introducing the new variable and then numerically solved by RK4 with a shooting procedure. The effect of emerging factors on the flow features is observed using graphs and elaborated in detail. From the analysis, the temperature is raised when the heat source is increased in both cases of wall expansion or contraction but declines in the case of heat sinks. In the case of a heat source, the temperature rises as the Hartmann and Prandtl numbers are enhanced, but in the case of a heat sink, the temperature falls. In the presence of heat sinks and injections, when the thermophoresis factor is increased, the concentration of nanoparticles is increased in both wall expansion and contractions. In both situations of wall extension or contraction, along with injection, the concentration of nanoparticles is a decreasing function of $Nb$, while the concentration of nanoparticles is an increasing function in the case of a heat source. Additionally, for the confirmation of the RK4 code, the total average square residue error and average square residue error are also presented. For the stability analysis, the current work is compared with published work, and excellent agreement is established. The novelty of the present study is to investigate the effect of chemical reaction on magnetized nanofluid flow over extending and shrinking porous pipes with heat generation and absorption.

In developing nations, the human immunodeficiency virus (HIV) infection, which can lead to acquired immunodeficiency syndrome (AIDS), has become a serious infectious disease. It destroys millions of people and costs incredible amounts of money to treat and control epidemics. In this research, we implemented a Legendre wavelet collocation scheme for the model of HIV infection and compared the new findings to previous findings in the literature. The findings demonstrate the precision and practicality of the suggested approach for approximating the solutions of HIV model. Additionally, establish an autonomous non-linear model for the transmission dynamics of healthy CD4⁺ T-cells, infected CD4⁺ T-cells and free particles HIV with a cure rate. Through increased human immunity, the cure rate contributes to a reduction in infected cells and viruses. Using the Routh-Hurwitz criterion, we determine the basic reproductive number and assess the stability of the disease-free equilibrium and unique endemic equilibrium of the model. Furthermore, numerical simulations of the novel model are presented using the suggested approach to demonstrate the efficiency of the key findings.

Thin film flow (TFF) problems received a lot of attention in recent times. Some frequent applications of TFF include polymer and metal extraction, elastic sheet drawing, food striating, heat exchanges, and device fluidization. Further improvement and enhancement of TFF need to be examined due to its practical applications. In the current analysis, viscoelastic nanofluid thin film flow through the vertical expanding sheet in the presence of a magnetic field with entropy function has been examined. The governing equations are transformed to first-order ODEs through similarity transformation and then solved numerically by using RK4 along with the shooting technique and ND Solve method. The impact of embedded parameters is discussed using graphs and tables. Physical quantities of interest are also discussed in detail. For the numerical solution, the error estimation and the residue error are calculated for the stability and confirmation of the mathematical model.

This study deals with the numerical solution of the human immunodeficiency virus (HIV) infection model, which is a significant problem for global public health. Acquired immunodeficiency syndrome (AIDS) is a communicable disease, and HIV is the causative agent for AIDS, which damages the ability of the body to fight against disease and easily usual innocuous infections attack the body. On entering the body, HIV infects a large amount of CD4+ T-cells and disturbs the supply rate of these cells from the thymus. Herein, we consider the model with variable source terms in which the production of these cells is a monotonically decreasing function of viral load. Based on the reproduction number, we describe the stability of free equilibrium. The continuous Galerkin–Petrov method, in particular the cGP(2)-method, is implemented to determine the numerical solutions of the model. The influence of different parameters on the population dynamics of healthy/infected CD4+ T-cells and free HIV particles are examined, and the results are presented graphically. On the other hand, the model is solved using the fourth-order Runge–Kutta method, and briefly, the RK4-method, and the results of the proposed schemes are compared with those obtained from other classical schemes such as the Bessel collocation method (BCM), Laplace Adomian decomposition method (LADM), perturbation iteration algorithm (PIA), modified variational iteration method (MVIM), differential transform method (DTM), and exponential Galerkin method (EGM), numerically. Furthermore, absolute errors relative to the RK4 method are computed to describe the accuracy of the proposed scheme. It is presented that the cGP(2)-method gains accurate results at larger time step sizes in comparison with the results of the aforementioned methods. The numerical and graphical comparison reveals that the proposed scheme yields more accurate results relative to other traditional schemes from the literature.

Non-Newtonian activity has been found in the manufacturing of coated sheets, foods, fibre optics, drilling muds, and plastics polymers. The Jeffery solvent is one of these fluid models that has really piqued the curiosity of scientists. With such a modelling approach, relaxation and delayed responses are possible. The investigation of boundary layer motions across a stretched cylinder has lots of applications in filament activities, crystallization and sheet fabrication, photonic circuits, recrystallization, and other industries. The convective heat transfer motion of a Jeffery non-Newtonian liquid influenced by a stretchy material with thermal performance is investigated in this paper. Applying transformation variables, the Physical quantities are converted to physical quantitates of the first order. The Runge–Kutta fourth order algorithm, in conjunction with the shooting strategy, is used to provide numerical results for motion and concentration profiles. The impacts of numerous factors on speed and concentration domains, such as the Hartman number, Schmidt number, and chemical reaction parameter, are depicted in graphs. The influence of Deborah numbers and Hartmann numbers on velocities components is the same. As the magnitude of the Hartmann number raised, boundary-layer thickness decreases. The concentration fields shrink as Sc increases and fall for the destructive reaction factor. The surface mass transfer decreases as Hartmann’s number is increased. The heat-transfer rate statistics data are very thoroughly recorded and analysed. The novelty of the present work is to investigate the Jeffery fluid in the presence of a magnetic field along with a chemical reaction over a nonlinear stretching sheet, which has not been investigated yet, so for limiting cases the present work is compared with the published work and good agreement is found.