Volume 20, Issue 1

In this article, a new method for processing trajectory parameter tests of flying targets with the geometric center of the screen as the response time of the detector is proposed. The superiority of this method over the conventional method for uniform thickness treatment is shown through the error and data analysis of the yaw angle, pitch angle, and flying speed. The relative distance between the test track and the real track shows the accuracy of the new method. The obvious statistical rules can be found for the errors of test parameters, which is conducive to the test research of random and violent vibrations of the target surface.

In this study, we propose an improved measurement method based on light-curtain sensor, and it can obtain the hitting coordinates of supersonic projectile in a larger dispersion area. First, we analyze the speed properties of the shock wave in an effective detection area (also called light curtain in our field), and then find their change rules related to several key factors, including flight speed of the projectile, its attitude, shape, and the temperature in the testing environment. Next we improve a measurement system using wide-angle light-curtain sensor combined with calibration device of the shock speed; especially, this device with three parallel laser beams can effectively measure the shock speed in the light curtain. According to the related structural relation, we derive several computational formulas combined with the shock speed to obtain the hitting position of the measured projectile. Through live ammunition experiments, the results show that the proposed method is feasible and reliable for the supersonic projectile. Besides high accuracy, it also has many advantages, such as fewer sensors, lower requirement for installation, and larger detection area, by comparison with previous measurement systems.

This research article examines the correctness of two new analytical methods for solving the internal solitary waves of shallow seas. To get the computational solutions to the positive (2 + 1)-dimensional Gardner–Kadomtsev–Petviashvili model, the extended simplest equation and modified Kudryashov methods are used. Numerous new traveling wave solutions in various forms are developed in order to assess the starting conditions required for the variational iteration technique, one of the most accurate semi-analytical methods. The semi-analytical solutions are used to demonstrate the precision of the solutions obtained and the analytical methods employed. The dynamical behavior of internal solitary waves in shallow waters is shown using many three-dimensional drawings. The performance of the used schemes demonstrates their efficacy and power, as well as their capacity to handle a large number of nonlinear evolution equations.

Using publicly available video of a diffusion cloud chamber with a very small radioactive source, I measure the spatial distribution of where tracks start and consider possible implications. This is directly relevant to the quantum measurement problem and its possible resolution, and it appears never to have been done before. The raw data are relatively uncontrolled, leading to caveats that should guide future, more tailored experiments. Aspects of the results may suggest a modification to Born’s rule at very small wave function, with possibly profound implications for the detection of extremely rare events such as proton decay, but other explanations are not ruled out. Speculatively, I introduce two candidate small-wavefunction Born rule modifications: a hard cutoff and an offset model with a stronger underlying physical rationale. Track distributions from decays in cloud chambers represent a previously unappreciated way to probe the foundations of quantum mechanics and a novel case of wave functions with macroscopic signatures.

Nuclear energy is a clean and popular form of energy, but leakage and loss of nuclear material pose a threat to public safety. Radiation detection in public spaces is a key part of nuclear security. Common security cameras equipped with complementary metal oxide semiconductor (CMOS) sensors can help with radiation detection. Previous work with these cameras, however, required slow, complex frame-by-frame processing. Building on the previous work, we propose a nuclear radiation detection method using convolution neural networks (CNNs). This method detects nuclear radiation in changing images with much less computational complexity. Using actual video images captured in the presence of a common Tc-99m radioactive source, we construct training and testing sets. After training the CNN and processing our test set, the experimental results show the high performance and effectiveness of our method.

17-4 PH stainless steel alloy has been widely used in the field of defence industry such as weapon equipment, aerospace, nuclear energy, and so on because of its high strength, high toughness, high temperature resistance, and corrosion resistance. In order to meet the flexible manufacturing requirements of multi-variety small batch complex structure products with lower cost and higher efficiency, selective laser-melted 17-4PH stainless steel alloy has become the focus of research in the field of rapid alloy manufacturing in recent years. In this article, the density characteristics and the distribution characteristics of holes and spheroidization phenomena of 17-4 PH pre-alloyed powder subjected to multidimensional temperature conduction under selective laser melting are studied, and the mechanism of defect generation under temperature conduction is proposed. Finally, the optimal selection of the combination of different process parameters was carried out by orthogonal test, and it was found that the comprehensive mechanical behaviour of the 17-4 PH stainless steel alloy after being formed exceeded the ASTM A564 standard (the yield strength is 1,132 MPa, the tensile strength is 1,323 MPa, and the elongation is 16.6%).

In this article, reconstructed displacement from the self-mixing signal is compared with the displacement obtained by the ceramic shear mode design piezoelectric accelerometer. Piezoelectric accelerometers are widely accepted due to the low output noise and wide frequency range, but nevertheless it is not contact-free. Self-mixing interferometric signals due to the vibrating target on which an accelerometer is attached are acquired by an external silicon type photodetector. The laser light hits directly the accelerometer as a target which is driven by the sum of two different sinusoidal frequencies of 150 and 300 Hz with different voltage levels.

The ceramic microchannel manufactured by stereolithography (SLA) can be used in many engineering cases. SLA is an accurate 3D printing technology, while the small geometry error is inevitable. The involved flow is always non-Newtonian fluids. Therefore, it is necessary to analyze Bingham fluids flow in the ceramic microchannel with geometry errors. To conduct the numerical simulations, a modified lattice Boltzmann (LB) model is presented. Then, the good consistency between the theoretical and numerical solutions demonstrates the effectiveness of the improved method. The required cases are analyzed by using the proposed method. Both the streamlines and outlet velocity distribution show that the geometry error increases the outlet velocity. The Bingham parameters are important factors in the flow of the microchannel.

Extreme environmental changes caused by the cavitation bubble collapse, such as high pressure, high temperature and the microjet, will cause pyrolysis reaction at the gas and liquid interface inside the bubble. Self-excited pulsed cavitation jet has an instantaneous strong pulse pressure, which leads to local hot spots surrounding the cavitation bubbles. The generation of strong oxidizing free radicals promotes easy ozone conversion into oxygen. Numerical simulations were conducted for ozone decomposition by cavitation jet. Three groups of different collision angles were applied to compare and analyze the ozone degradation reaction. Results showed that the collision angle has a certain influence on the chemical reaction intensity, the degradation of ozone, and oxygen production. At the collision angle of 180°, the chemical reaction was the most violent, with ozone degradation and oxygen production at the highest level, followed by 120° and lowest at 90°.

Modeling of the electrostatic potential for fully depleted (FD) silicon-on-insulator (SOI) metal-oxide-semiconductor field effect transistor (MOSFET) is presented in this article. The modeling is based on the analytical solution of two-dimensional Poisson’s equation obtained by using the homotopy perturbation method (HPM). The HPM with suitable boundary conditions results in the so-called HPM solution in general and closed-form, independent of the surface potential. The HPM solution has been applied in modeling the output characteristics of the FDSOI MOSFET, which show good agreement compared with the numerical results.

Aiming at the problem of poor construction accuracy of the cellular three-dimensional (3D) mechanical microenvironment, this article studies the cellular 3D mechanical microenvironment based on machine vision. The gelatin methacrylate microgel column was prepared by NIH/3T3 mouse fibroblast and precursor solution of gelatin methacrylate microgel. The gelatin methacrylate microgel array with magnetic end was adopted. The external magnetic field was used to load microgel array and build 3D mechanics microenvironment model. The deformed pictures of hydrogel under magnetic field were obtained by fluorescence microscope. The scanning electron microscope was used to characterize the pore structure of gelatin methacrylate hydrogel. The pictures obtained by machine vision method were used to calculate the deformed parameters of sample. The machine vision method adopted the discrete cosine transform for autofocus, and then used the image analysis and processing technology to identify and estimate the cell motion parameters. After getting the cell motion parameters, Comsol multiphysics (COMSOL) multiphysics multifield coupling finite element analysis software was adopted. The correlative numerical simulation method and gel deformed simulation method were used to obtain the mechanical changes of cells in the 3D mechanical microenvironment. Experimental results show that the modulus of gelatin methacrylate microgel is changed significantly during the tensile loading. The tensile strain and the cell spreading area are nonlinearly related. The increase in stiffness of the hydrogel substrate helps to promote cell proliferation to a certain extent.

In this research paper, the authors aim to establish a novel algorithm in the finite difference method (FDM). The novel idea is proposed in the mesh generation process, the process to generate random grids. The FDM over a randomly generated grid enables fast convergence and improves the accuracy of the solution for a given problem; it also enhances the quality of precision by minimizing the error. The FDM involves uniform grids, which are commonly used in solving the partial differential equation (PDE) and the fractional partial differential equation. However, it requires a higher number of iterations to reach convergence. In addition, there is still no definite principle for the discretization of the model to generate the mesh. The newly proposed method, which is the SM method, employed randomly generated grids for mesh generation. This method is compared with the uniform grid method to check the validity and potential in minimizing the computational time and error. The comparative study is conducted for the first time by generating meshes of different cell sizes, i.e. , 10 × 10 , 20 × 20 , 30 × 30 , 40 × 40 10\times 10,\hspace{.25em}20\times 20,\hspace{.25em}30\times 30,\hspace{.25em}40\times 40 using MATLAB and ANSYS programs. The two-dimensional PDEs are solved over uniform and random grids. A significant reduction in the computational time is also noticed. Thus, this method is recommended to be used in solving the PDEs.

Mansouri and Sexl (MS) presented a general framework for coordinate transformations between inertial frames, presupposing a preferred reference frame the space-time of which is isotropic. The relative velocity between inertial frames in the standard synchronization is shown to be determined by the first row of the transformation matrix based on the MS framework. Utilizing this fact, we investigate the relativistic velocity addition. To effectively deal with it, we employ a diagram of velocity that consists of nodes and arrows. Nodes, which are connected to each other by arrows with relative velocities, represent inertial frames. The velocity composition law of special relativity has been known to be inconsistent with the reciprocity principle of velocity, through the investigation of a simple case where the inertial frames of interest are connected via a single node. When they are connected through more than one node, many inconsistencies including the violation of the reciprocity principle are found, as the successive coordinate transformation is not reduced to a Lorentz transformation. These inconsistencies can be cured by introducing a reference node such that the velocity composition is made in conjunction with it. The reference node corresponds to the preferred frame. The relativistic velocity composition law has no inconsistencies under the uniqueness of the isotropic frame.

The electroosmotic flow of non-Newtonian fluid–Eyring fluid in microparallel pipes under high zeta potential driven by the combination of pressure and electric force is studied. Without using the Debye–Hückel (DH) linear approximation, the numerical solutions of the fluid potential distribution and velocity distribution obtained using the finite difference method are compared with the analytical approximate solutions obtained using the DH linear approximation. The results show that the numerical method in this article is effectively reliable. In addition, the influence of various physical parameters on the electroosmotic flow is discussed in detail, and it is obtained that the velocity distribution of the Eyring fluid increases with the increase in the electric potential under the high zeta potential.

New solitary wave solutions of the Calogero–Degasperis–Fokas (CDF) equation via two modified methods called improved simple equation and modified F-expansion schemes are investigated. Numerous types of results are obtained in the form of hyperbolic functions, trigonometric functions and elliptic functions. Moreover, some of the derived solutions are illustrated as two-dimensional, three-dimensional and contour graphical images that were plotted with the assistance of computational software Mathematica, which gave useful knowledge to study the physical phenomena of the CDF model. The investigated solutions have fruitful advantages in mathematical physics.

This article reports a quick-setting agent named AS-G1. In the current offshore oil exploitation, there are usually wastes mixed with the drilling fluid, completion fluid, cement slurry, etc. To protect the marine environment, offshore construction workers need to weakly solidify these wastes so that they can be transported to land for disposal. The accelerating agent can reduce the fluidity of offshore cementing wastes and achieve the effect of solidifying wastes. Compare the time for the three cement slurries to lose fluidity with the addition of accelerating agents. Evaluate the setting time of cement slurry under the action of the accelerating agent after adding two drilling fluids. The solidification effect of this kind of accelerating agent on cementing waste is verified. It can be applied to waste treatment in oil fields.

Ion beam-induced luminescence (IBIL) is a versatile technique used to elucidate the chemical bond’s nature and analyze the defects study and impurities present in the material. In this study, IBIL spectra of phosphorus-irradiated sapphire has been analyzed under 2 MeV proton beam as a function of ion dose ranging from 1 × 10 14 to 10 × 10 14  ions/cm 2 at room temperature in the wavelength range of 200–1,000 nm. The IBIL spectrum shows three kinds of luminescence features. The bands centered at 419 nm as F center and 330 nm as F + center are associated with oxygen vacancies. The third kind of luminescence feature located at 704 nm is related to chromium impurities present in the crystal. The luminescence spectrum of the phosphorus-irradiated sapphire has been correlated with the spectrum obtained from pristine sapphire. The finding indicates that the intensity of defects due to phosphorus irradiation is reduced. As the proton ion fluence increases, the F and F + center luminescence intensity eventually varies; it turns out that in phosphorus-irradiated sapphire, single crystal defects were reduced and the optical quality was improved.

A physical model can be used to judge cementing quality to help drilling engineering. This article reports a physical model based on the XGboost algorithm to solve the cementing quality prediction problem of oil and gas wells. Through the physical model, the nonlinear, time-varying, and uncertain influencing factors, the high latitude of the data set, the lack of data, data imbalance and other characteristics are comprehensively analyzed. Finally, through numerical example verification, the physical model we reported can effectively predict the key factors affecting quality, improve process quality and reduce unit cost.

Stress concentrations typically exist around the perimeter of an opening and on attached structures, thereby resulting in a potential risk of crack initiation. Experimental and numerical methods on stress concentration distribution analysis can be applied in this study. This study reveals the differences in stress concentration distributions around various types of slots. Typical slots have been selected to discuss the influence on stress concentration distribution when the connections of flat bar and connection plate are considered. This concept is novel given the experiments conducted and finite element method (FEM) results found under complex loads. The FEM is used to compare calculated results with experimental data, and continuous plotting of numerical results can verify the outcomes. The results show the stress concentration distribution around the selected slot edge, where peak stress appears around the openings of different types of slots.

For narrow tubes, red blood cells concentrate in the core region, leaving an annular zone called cell-free layer. This has an impact on both the tube hematocrit level (Fåhraeus effect) and the apparent blood viscosity (Fåhraeus–Lindqvist effect). Blood flow, mass transfer across the microvessel membrane, and diffusion in the tissue affect the solute concentration profiles. The Krogh tissue cylinder concept, limiting mass transfer to a cylinder around each microvessel, and the marginal zone concept (introduced by Haynes to analyze blood flow dynamics in narrow tubes) are both used to develop a model for solute transfer from blood in microvessels to the surrounding tissues, based on fundamentals. The analysis accounts for advection and diffusion in each zone of the microvessel, solute transport in the microvessel membranes, and diffusion and reaction in the tissues. The present investigation provides an analytical solution. The approach can be extended to treat other kinetic models, while accounting for Fåhraeus and Fåhraeus–Lindqvist effects in blood microvessels. The model is validated against published results for glucose transport from blood to tissue.

The finite-size effect plays a key role in one-dimensional Bose–Einstein condensation (BEC) of photons since such condensation cannot occur in the thermodynamic limit due to the linear dispersion relation of photons. However, since a divergence difficulty arises, the previous theoretical analysis of the finite-size effect often only gives the leading-order contribution. In this article, by using an analytical continuation method to overcome the divergence difficulty, we give an analytical treatment for the finite-size effect in BEC. We show that the deviation between experiment and theory becomes much smaller by taking into account the next-to-leading correction.

Hot air drying is widely adopted to extend the shelf life of Pleurotus eryngii , which is an edible fungus with high nutritional value and large market demand. Understanding moisture transfer during hot air drying is essential for both quality improvement and energy-efficient dryer design. In this study, we investigated the drying kinetics of P. eryngii slices with different thicknesses (4, 8, and 12 mm) under different hot air temperature levels (40, 50, 60, 70, and 80°C) and a constant air velocity (2 m/s). It is found that the drying rate increases with the increase of the hot air temperature or the decrease of the thickness of P. eryngii slices. Only a falling rate period was observed during the hot air drying. We used eight mathematical models to describe the drying kinetics of P. eryngii slices and found that the logarithmic model fits the experimental data best. The fitted effective moisture diffusivity of P. eryngii slices is in the range of 3.34 × 10 − 9 3.34\times {10}^{-9} to 2.25 × 10 − 9  m 2 / s 2.25\times {10}^{-9}{\text{ m}}^{2}/\text{s} , and the fitted drying activation energy is 19.30 kJ/mol, agreeing with the results in the literature. Additionally, we noticed that the color of dried P. eryngii slices becomes darker with the increase of hot air temperature due to the Maillard browning reaction. This study helps to understand the drying kinetics of P. eryngii slices during the hot air drying and guides the drying process optimization.

Currently, there are more perfect theoretical basis and operation methods for the research of the Cu 2 ZnSnS 4 (CZTS) solar cell characteristics, but the experimental process is tedious. In this article, to measure the characteristics of the CZTS solar cells more accurately and quickly, the computer-aided measurement method was used. During testing the characteristics of solar cells, the results were collected and analyzed by using LabCoder and Origin software. By designing experiments and using software to record data and complete solar cell characterization tests in one step, the number of artificial changes in resistance during testing is reduced. In the experiments, the data can be obtained in real time by using experimental results of computer-aided measurement technology, which can significantly improve the experimental efficiency. Through computer real-time monitoring, the maximum output power of as-prepared solar cells is P m  = 1.62 W, and the calculated filling factor remains at 86%. It means that computer-aided measurement technology is suitable for the experiment of CZTS solar cell characteristics.

In this work, we study the quantum chromodynamics phase diagram at finite temperature and non-zero chemical potential in the framework of the SU(2) flavor of the Polyakov–Nambu – Jona–Lasinio model (PNJL). Applying multiple reflection expansion to cubic and spherical finite volumes of different sizes and boundary conditions, the chiral phase transition and deconfinement of strongly interacting matter are analyzed. We give special attention to find and locate the critical endpoint and locating the critical endpoint, if it exists, as a function of the volume size and its shape, and its dependence of chemical potential and temperature.

In this article, we focus on investigating the new coupled Konno–Oono equation that arises in the magnetic field. An effective technology called the Exp-function method (EFM) is utilized to find abundant analytical solutions. By this method, four families (28 sets) of the exact solutions, such as bright solitary, dark solitary, bright–dark solitary, double-bright solitary, double-dark solitary and kinky bright–dark solitary wave solutions, are constructed. The performances of the real, imaginary and absolute parts of the solutions are presented in the form of 3D contours. The results show that the EFM is a promising method to construct abundant analytical solutions for the partial differential equations arising in physics.

In this work, a Gaussian laser beam is propagated through a thermally turbulent region before passing through a point diffraction interferometer to produce a circular interferogram. This was done to ascertain how turbulent windstreams of various wind speeds and temperatures affect a laser beam when directed at different angles to the beam axis. The interferometric results portray a clear dependence on the angle of application. That is, deviations away from 90° result in increased wavefront fluctuations. The refractive index structure constant, Rytov variance, and Fried’s parameter were computed to quantify each turbulent model. The attributed strength regimes of these atmospheric parameters were in varying degrees of agreement with the interferometric data. These contradictions and resulting conclusions were discussed in full.

The investigation of thermal transport in the nanofluid over a curved Riga surface is significant and extensively used in many industries as well as in engineering. Therefore, the study is conducted to analyze the thermal transport rate in H 2 O composed of nanomaterial, namely, carbon nanotubes (CNTs). To improve the thermal conductance, a thermal conductivity correlation based on the length and radius of CNTs is plugged in the energy equation. After that, the flow model was reduced into a self-similar form via feasible transformations and tackled numerically. From the plotted results, it is experienced that the nanofluid velocity drops against a more curved surface. The momentum boundary layer intensifies against larger curvature. An enhanced temperature is experienced in the nanofluid due to varying the parameters. Further, thermal conductivity of the nanofluids rises due to the high volume fraction factor, which plays a significant role in thermal transport. Moreover, the local thermal performance rises linearly against M .

Kadomtsev–Petviashvili equation is used for describing the long water wave and small amplitude surface wave with weak nonlinearity, weak dispersion, and weak perturbation in fluid mechanics. Based on the modified symbolic computation approach, the multiple rogue wave solutions of a generalized (3+1)-dimensional variable-coefficient Kadomtsev–Petviashvili equation are investigated. When the variable coefficient selects different functions, the dynamic properties of the derived solutions are displayed and analyzed by different three-dimensional graphics and contour graphics.

Optical waveguides play a vital role in the manufacture of various optical devices due to their unique performances and high-degree integration. We report on the preparation and characterization of the planar waveguides in the Dy 3+ /Tm 3+ -codoped GeS 2 –Ga 2 S 3 –PbI 2 chalcohalide glass. The waveguide was formed by the 400 keV H + -ion implantation with a dose of 8 × 10 16 ions/cm 2 . Its thermal stability was studied by annealing at 260°C for 1 h. The changes in the nuclear energy loss with the implantation depth were simulated by the stopping and range of ions in matter (SRIM 2013). The dark-mode characteristics of the waveguide were measured by the prism coupling method. The refractive index distribution of the optical waveguide was reconstructed by the reflectivity calculation method. The modal profile of the waveguide structure was calculated by the finite-difference beam propagation method (FD-BPM). The thermally stable proton-implanted Dy 3+ /Tm 3+ -codoped GeS 2 –Ga 2 S 3 –PbI 2 chalcohalide glass waveguide is expected to be applied in mid-infrared integrated optical devices.

Based on the positive quadratic function method, the rich nonautonomous solutions of a generalized (2+1)-dimensional variable-coefficient breaking soliton equation with different wave structures are given. In this case, due to the influence of nonlinearity and dispersion, the characteristics, amplitude and velocity of nonautonomous wave will change with time. The breather wave and the interaction among lump wave, solitary wave and periodic wave solutions are studied. For different choices of arbitrary functions in these solutions, the corresponding dynamic properties are demonstrated.

The aim of this study is to investigate the numerical analysis of an innovative model containing, bioconvection phenomena with a gyrotactic motile microorganism of magnetohydrodynamics Williamson nanofluids flow along with heat and mass transfer past a stretched surface. The effect of thickness variation and thermal conductivity feature is employed in the model. Bioconvection in nanofluid helps in bioscience such as in blood flow, drug delivery, micro-enzyme, biosensors, nanomedicine, for content detection, etc . For simulation procedure, the mathematical partial differential equations are converted into dimensionless systems owing to dimensionless variations such as magnetic field, power index velocity, Williamson parameter, wall thickness parameter, thermal conductivity variation, Prandtl number, thermal radiation, Brownian motion, Lewis number, Peclet number, and different concentration parameter, etc . For numerical simulation, New Iterative Technique (NIM) numerical algorithm is adopted and employed for the linear regression planned for the proposed model. For comparison purposes, the homotopy technique is employed on the flow model. Close agreement is seen between both methods revealing the accuracy and consistency of NIM numerical technique. Many features of no-scale constraints are evaluated through graphical data for a key profile of the flow model. Results show that microorganism concentration is heavy due to the magnetic effect and Hall current.

The Pareto model corresponds to the power law widely used in physics, biology, and many other fields. In this article, a new generalized Pareto model with a heavy right tail is introduced and studied. It exhibits an upside-down bathtub-shaped failure rate (FR) function. The moments, quantiles, FR function, and mean remaining life function are examined. Then, its parameters are estimated by maximum likelihood, least squared error, and Anderson–Darling (a weighted least squared error) approaches. A simulation study is conducted to verify the efficiency and consistency of the discussed estimators. Analysis of Floyd River flood discharges in James, Iowa, USA, from 1935 to 1973 shows that the proposed model can be quite useful in real applications, especially for extreme value data.

Three effective methods, namely, the simplified extended tanh-function method (SETFM), variational method (VM) and He’s frequency formulation method (HFFM) are employed to investigate the Fokas system that arises in the monomode optical fibers. Fifteen sets of the soliton solutions such as the bright soliton, dark soliton, bright-dark soliton, double-dark soliton, double-bright soliton, triple-bright soliton, kinky periodic soliton and perfect periodic soliton solutions are developed. The dynamic performances of the different soliton solutions are plotted via the 3-D contours and 2-D curves to interpret the physical behaviors by assigning reasonable parameters. From the results obtained from this study, it is found that three proposed methods are promising ways to seek various soliton solutions of the PDEs in optical physics.

The main goal of this inspection is to explore the heat and mass transport phenomena of a three-dimensional magnetohydrodynamic (MHD) flow of ternary hybrid nanoliquid through a porous media toward a stretching surface. Nowadays, the low thermal conductivity is the key problem for scientist and researchers in the transmission of heat processes. Therefore, in order to improve the thermal conductivity of different base liquids, the scientist and researchers are mixing numerous types of solid particles in the base fluids. That is why the authors have mixed three different types of nanoparticles such as graphene oxide, silver, and copper in a kerosene oil base liquid. The influences of Hall current and ion-slip are also considered. Furthermore, the flow behavior is analyzed under the appliance of Darcy–Forchheimer, activation energy, and chemical reaction. By using the concept of boundary layer theory, the flow equations are modeled in the form of higher order nonlinear partial differential equations (PDEs) along with convective boundary conditions. Suitable similarity transformations are used for the transformation of higher order PDEs into the higher order nonlinear ordinary differential equations (ODEs). Analytical scheme known as the homotopic scheme is utilized for the simulation of the current problem. The impacts of discrete flow parameters on the velocities, temperature, and concentration profiles of the ternary hybrid nanoliquid are inspected. The skin friction coefficients, Nusselt number, and Sherwood number of the ternary hybrid nanofluid are investigated against various flow parameters. The outcomes of the current analysis showed that primary velocity of the ternary hybrid nanoliquid is augmented via Hall current and ion-slip number, while the reverse trend is observed via porosity parameter, Darcy–Forchheimer parameter, and magnetic field parameter. On the other hand, the higher values of Hall current and magnetic parameter enhanced the secondary velocity of the ternary hybrid nanoliquid, while the secondary velocity was reduced due to the increasing ion-slip number and rotation parameter. It is found that the heat transfer rate of the ternary hybrid nanofluid is 46% greater than the silver nanofluid.

In this article, we model the current and voltage across the weak link between two superconductors. This gives us a nonhomogeneous, nonlinear parametric-driven sine-Gordon equation with phase shifts. This model equation cannot be solved directly but can be approximated. For the approximations, we use two methods, and analytic perturbation method and the numerical approximation method known as the Runge–Kutta method. For the analytic method, we construct a perturbation expansion method with multiple-scale expansion. We discuss the parametric-driven in the sine-Gordon equation with phase shifts for the 0– π –0 junction. Further, we also describe the breathing modes for various order of perturbation. At the end, we compare the solutions obtained via perturbation and numerical methods of parametric-driven sine-Gordon equation with phase shifts. Finally, we concluded that the modes of the breathing decay to a constant in both cases. Also we found a good agreement between both approximate methods.

In this article, the magnetofluid unsteady electroosmotic flow (EOF) of Jeffrey fluid with high zeta potential is studied by using the Chebyshev spectral method and the finite difference method. By comparing the potential distribution and velocity distribution obtained by the Chebyshev spectral method and finite difference method, it is concluded that the Chebyshev spectral method has higher precision and less computation. Then the numerical solution obtained by the Chebyshev spectral method is used to analyze the flow characteristics of Jeffrey fluid at high zeta potential. The results show that the velocity of Jeffrey fluid increases with the increase of the wall zeta potential and electric field intensity. The oscillation amplitude of velocity distribution increases with the increase of relaxation time, but decreases with the increase of retardation time. With the increase of Hartmann number, the velocity first increases and then decreases. The positive pressure gradient promotes the flow of fluid, and the reverse pressure gradient impedes the flow of fluid.

This work studies the influence of plasma-activated water (PAW) on the decontamination of beef and its influence on the color, pH, the thiobarbituric acid reactive substance values (TBARS), and total volatile basic nitrogen (TVBN) values of meat. PAW was generated using non-thermal atmospheric pressure plasma jet (NTAPPJ). He + 0.2% N 2 and He + 0.2% O 2 were used as worker gas to generate PAW. The PAW produced by the He + O 2 plasma system exhibited a higher potential for decontamination of beef than that produced by the He + N 2 plasma system. The lightness value ( L *) of treated beef does not exhibit a noticeable difference with the control one. TBARS values of all treated beef were lower than the rancidity threshold but significantly greater than that of control samples. The TVBN value of control beef samples reached the decay threshold after 18 days of stockpiling, but treated beef remained good. This work reveals that PAW can potentially inhibit the growth of microorganisms in beef.

Shield pumps which transport a variety of complex media are widely used in chemical industry, mineral industry, and other fields. However, the hard particles in the media erode the flow passage in the shield pump, seriously affecting the service life of the pump. Therefore, it is important to study the erosion process in the flow passage to extend the service life of the pump. This erosion process in the shield pump can be investigated by experiments, but it is difficult for the current experimental method to copy the real industrial service environment of impellers. For example, the environment temperature and speed range are found difficult to be reached by the current experimental method. Comparatively, the simulation by finite element method can overcome the above deficiency. In this article, the ANASYS software is used to simulate the erosion process in shield pump flow passage due to hard particles. Specifically, the structural static analysis module is used to build the model of thermal barrier coating components and hard particle components. Then the variation law of stress, strain, and material deformation of the flow passage components under concentrated force is obtained. Second, the extended finite element method is used to study the crack propagation caused by the erosion process. A linear elastic–linear softening constitutive model is established to simulate the stress variation during the crack propagation and material removal under the continuous erosion from hard particles. The proposed law regarding stress variation and crack propagation in the erosion process in this study contributes to theoretical support for damage detection and service life extension of shield pumps.

In this article, we investigate the mechanics of breathing performed by a ventilator with different kernels by an effective integral transform. We mainly obtain the solutions of the fractional respiratory mechanics model. Our goal is to give the underlying model flexibly by making use of the advantages of the non-integer order operators. The big advantage of fractional derivatives is that we can formulate models describing much better the systems with memory effects. Fractional operators with different memories are related to different types of relaxation process of the non-local dynamical systems. Additionally, since we consider the utilisation of different kinds of fractional derivatives, most often having benefit in the implementation, the similarities and differences can be obviously seen between these derivatives.

The wind turbine system is the core equipment of wind power generation. Scientific formulation of an extended warranty (EW) scheme to optimize the cost-effectiveness ratio per unit time for a wind turbine system is one of the key concerns both for users and manufacturers. Based on the failure dependence analysis of the multi-component system, the EW cost model and availability model of the multi-component system are established. Based on the EW cost model and availability model, the cost-effectiveness ratio model per unit time is constructed. Through the case study, the optimal EW scheme of the wind turbine system is obtained via genetic algorithm, so as to minimize the cost-effectiveness ratio per unit time. The results of fitting prediction analysis and flexible decision analysis show that the model can excellently predict the minimum warranty cost and maximum availability of failure dependence wind turbine systems and can supply different EW schemes for users and manufacturers to choose from under a specific cost–effectiveness ratio. Through sensitivity analysis, reasonable suggestions for optimizing the EW scheme of the wind turbine system are proposed.

In this work, a (2+1)-dimensional generalized Hirota–Satsuma–Ito equation realized to represent the propagation of unidirectional shallow water waves is investigated. We first study the breather wave solutions based on the three-wave method and the bilinear form. Second, the double-periodic soliton solutions are obtained via an undetermined coefficient method, which have not been seen in other literature. We present some illustrative figures to discuss the dynamic properties of the derived waves.

First-principle calculations are used to study the electronic structures, electronic and optical properties of pure, phosphorus-doped, aluminum-doped, and phosphorus and aluminum co-doped graphene. The gap between the conduction band and valence band of intrinsic graphene is zero. However, when graphene is doped with P, Ga, and P–Ga, the gap in energy will be opened and to a different extent. In the three different doping results, the gap values between the conduction and valence bands of P, Ga, and P–Ga graphene are 0.11, 0.35, and 0.39 eV, respectively. When graphene is doped with P–Ga, more electrons (1.40 e) will be gained by carbon atoms compared to P-doped graphene (0.61 e), while fewer electrons (1.49 e) will be transferred to carbon atoms compared to Ga-doped graphene (1.75 e). After doping with P, Ga, and P–Ga, the overall intensity of the graphene absorption peak is weakened and more pronounced relative to the low-frequency peaks. This result can fully demonstrate that the band gap of the doped graphene system can be better tuned by adding phosphorus and gallium atoms.

The development of nanofluid technology has become a key research area in physics, mathematics, engineering, and materials science. Nowadays, in many industrial applications, nanofluids are widely used to enhance thermophysical properties such as thermal diffusivity, thermal conductivity, and convective heat transfer. Scientists and engineers have established interests in the direction of flow problems developed via disk-shaped bodies. There are various logics to discuss flow phenomenon due to rotating bodies, but its applications include in thermal power engineering system, gas turbine rotors, air cleaning machines, aerodynamics, etc. Nowadays manufacturing industries have inaugurated to select liquid based on heat transfer properties. Therefore, this article focuses on studying the laminar incompressible nanofluid between two parallel disks. Mathematical formulations of the law of conservation of mass, momentum, and heat transfer are investigated numerically. By using suitable similarities, the flow equations are converted into nonlinear ordinary differential equations. The resulting equations were solved numerically via MATLAB software. The effects of physical parameters of interest, such as Reynolds number, magnetic factor, Brownian parameter, and thermophoresis parameter on normal velocity, streamwise velocity, temperature, and concentration profiles are computed and presented using the graphs. The results revealed that the energy profile significantly rises, and the profile moves closer to the upper disk by enhancing the Brownian motion and thermophoresis parameter. The dynamics behind this is that by increasing the Brownian motion, the boundary layer wideness increases which increases the temperature. Moreover, streamwise velocity increases for large values of Reynolds number. Besides, the thermophoresis profile increases for large values of the thermophoresis factor. It could be observed that shear stress at nonporous/porous disk is adjusted by selecting a suitable value of injection velocity at the porous disk. Also, normal velocity decreases by increasing the parameter M .

With the rapid development of modern high technology and continuous improvement of production technology, stringent requirements have been imposed on modern barrel weapons in terms of precision, range, power, and mobility. This needs a substantial improvement and optimization of the detection equipment used to test the performance of barrel weapons. In the present work, an optimization method based on a light screen with a reflection for effectively and economically detecting bullets from barreled weapons within a large detection area is proposed. First, the detection principle of this system is described in detail. Next, the mathematical model of system detection performance is established. Then, the system is simulated, and the simulation results show the ability to realize the effective detection of a small projectile with a diameter of 5.8 mm through an area of 10 m × 10 m. The detection performance at different coordinates of the detection area is symmetrically distributed about the diagonal. Besides, the detection performance is improved with an increase in the bullet diameter and the laser power, respectively. Finally, an equal-scale reduction system with a detection area of 4 m × 4 m is constructed to perform a live ammunition shooting experiment. The distribution and variation of detection performance obtained experimentally are consistent with the simulation. Consequently, the proposed optimization method can meet the requirements concerning high detection performance, large detection area, and low cost.

In controlling the angle error of laser profilometer contact measurement, the control model used in the past is subject to more external interference, which affects the measurement of other parameters, resulting in poor error control effect. Therefore, the angle error control model of laser profilometer contact measurement is designed by determining the initial zero position of the profilometer measuring sensor, compensating the non-linear error, designing the interference signal processing circuit, and avoiding the error measurement influenced by external factors. From the main error sources such as the perpendicularity, standard error, sensor error and other errors of the coordinate axis of the profilometer, the accuracy is distributed. According to the equal action principle, the measurement uncertainty of the profilometer is calculated, and the measurement is obtained. According to the interference signal processing circuit and measurement index, the serial communication control circuit is designed, and the angle error control model of laser profilometer contact measurement is constructed. The experimental results show that the designed laser profilometer contact measurement angle error control model has high precision and does not affect other parameters in the control process, which shows that the control model has good effect in practical application.

In this article, the side-entry agitator commonly used in the wet desulfurization absorption tower of a 300 MW thermal power unit was taken as the research object, and the gas–liquid two-phase flow field in the stirring tank was numerically simulated by using the two-fluid model based on Euler–Euler method. The vertical and horizontal velocity field distribution and gas phase distribution in the stirring tank were studied. The results showed that the side-entry agitator formed a “fountain” circulating flow in the stirring tank. The high-speed region of the liquid flow was mainly concentrated near the mixing blade and the bottom banded region. The range of large changes in the fluid velocity was mainly concentrated from the bottom of the mixing tank to 2–3 m from the bottom. The distribution of the oxidizing air was concentrated in the middle of the stirring tank. The mixing effect of two phases in the stirred tank was good, and the oxidizing air was fully diffused. The numerical study in this article has reference significance for in-depth understanding of the flow field and mixing effect of the side-entry agitator.

The current work focuses on the solutions of the Kadomtsev and Petviashvili (KP) equation, which models nonlinear waves in a dispersive medium. The modified auxiliary equation approach is utilized to find analytical solutions of the KP equation. Consequently, a set of solutions including Jacobi elliptic solutions and solitary and periodic waves solutions is obtained. The geometry of the derived solutions is plotted with an appropriate choice of the parameters. It can be seen that the proposed method is powerful and can be used to solve nonlinear partial differential equations due to its simplicity.

We investigated the damage morphology of porous silicon oxide film with a periodic hexagonal hole array irradiated by nanosecond pulsed laser, both experimentally and numerically. To understand the damage morphology, the temperature field distribution and the thermal stress distribution during the laser radiation process were investigated by finite element method. The simulation results show that the thermal stress regulated by periodic structural surface is the reason for the circumferential and discrete distribution of the damage points. The results provide ideas for improving the laser damage resistance of the structural surfaces.

The main aim of this article is to study a new generalizations of the Gauss hypergeometric matrix and confluent hypergeometric matrix functions by using two-parameter Mittag–Leffler matrix function. In particular, we investigate certain important properties of these extended matrix functions such as integral representations, differentiation formulas, beta matrix transform, and Laplace transform. Furthermore, we introduce an extension of the Jacobi matrix orthogonal polynomial by using our generalized Gauss hypergeometric matrix function, which is very important in scattering theory and inverse scattering theory.

When a high-energy laser acts on a film surface, plasma flashes of both the air and film can be generated simultaneously. However, when the conventional plasma flash method is used to identify thin film damage, there is a misjudgment problem caused by the inability to distinguish the air and film plasma flashes. In order to solve the problem of misjudgment, the ignition times of air and thin film plasma flashes can be obtained, respectively. If the ignition times of air and thin film plasma flashes are not equal, they can be distinguished from the time difference. In this paper, a nanosecond Nd:YAG pulse laser is used to break down the air at room temperature and pressure, and the theoretical and experimental values of the ignition time of air plasma flash are obtained. The curves of the ignition time of air plasma flash with the laser wavelength, incident energy, focusing spot, and pulse width are simulated. The reasons for the changes are analyzed from the perspectives of multiphoton absorption, cascade ionization theory, and electromagnetic theory of laser breakdown gas. The results show that when the laser pulse width is 10 ns, the energy is 160 mJ, and the spot radius is 0.015 cm. The theoretical and experimental values of the ignition time of air plasma flash are 2.146 and 2 ns, respectively, which are in good agreement. Larger values of laser focus spot size and pulse width relate to a longer ignition time of the air plasma flash, whereas larger values of laser wavelength and incident energy are related to a shorter ignition time. The research reflects the characteristics and electronic transition of air plasma, as well as the micromorphological evolution of the interaction between laser and air, presents the process of air plasma flash generation and growth, and reveals the ignition mechanism of air plasma. It not only provides a basis for improving the traditional plasma flash identification method to identify film damage but also has a certain scientific significance for studying the generation mechanism of laser-supported combustion waves and detonation waves.

The variant Boussinesq equation has significant application in propagating long waves on the surface of the liquid layer under gravity action. In this article, the improved Bernoulli subequation function (IBSEF) method and the new auxiliary equation (NAE) technique are introduced to establish general solutions, some fundamental soliton solutions accessible in the literature, and some archetypal solitary wave solutions that are extracted from the broad-ranging solution to the variant Boussinesq wave equation. The established soliton solutions are knowledgeable and obtained as a combination of hyperbolic, exponential, rational, and trigonometric functions, and the physical significance of the attained solutions is speculated for the definite values of the included parameters by depicting the 3D profiles and interpreting the physical incidents. The wave profile represents different types of waves associated with the free parameters that are related to the wave number and velocity of the solutions. The obtained solutions and graphical representations visualize the dynamics of the phenomena and build up the mathematical foundation of the wave process in dissipative and dispersive media. It turns out that the IBSEF method and the NAE are powerful and might be used in further works to find novel solutions for other types of nonlinear evolution equations ascending in physical sciences and engineering.

This article investigates the extended homoclinic (heteroclinic) breather wave solutions and interaction periodic and dark soliton solutions to the nonlinear vibration and dispersive wave systems. The solutions include periodic, breather, and soliton solutions. The bilinear form is considered in terms of Hirota derivatives. Accordingly, we utilize the Cole–Hopf algorithm to obtain the exact solutions of the ( 2 + 1 2+1 )-dimensional modified dispersive water-wave system. The analytical treatment of extended homoclinic breather wave solutions and interaction periodic and dark soliton solutions are studied and plotted in four forms of density plots. A nonlinear vibration system will be studied. Employing appropriate mathematical assumptions, the novel kinds of the extended homoclinic breather wave solutions and interaction periodic and dark soliton solutions are derived and constructed in view of the combination of kink, periodic, and soliton for an extended homoclinic breather and also a combination of two kinks, periodic and dark soliton in terms of exponential, trigonometric, hyperbolic functions for interaction periodic and dark soliton of the governing equation. To achieve this, the illustrative example of the ( 2 + 1 2+1 )-D modified dispersive water-wave system is furnished to demonstrate the feasibility and reliability of the procedure applied in this research. The trajectory solutions of the traveling waves are offered explicitly and graphically. The effect of the free parameters on the behavior of designed figures of a few obtained solutions for two nonlinear rational exact cases was also considered. By comparing the suggested scheme with the other existing methods, the results state that the execution of this technique is succinct, extensive, and straightforward.

The fractional structures of variables using Riemann–Liouville notion have been analyzed by various authors. The novel idea of this article is to introduce the new notion of weighted behavior on random variables using integral inequalities. In view of these, we obtain some new generalized fractional inequalities by using this new fractional integration of continuous random variables.

Light is a well-known electromagnetic wave that propagates, transmits, reflects, and polarizes in any medium. Waves have a huge technical impact as a determinant of human life because of their qualities. Using real geometrical Earth’s magnetic field, this article investigates the latitude and seasonal fluctuation of polarization magnitude of a polarized characteristic wave (no electric flux in the wave’s propagation direction) in the ionospheric plasma (the examined conditions). Both the volume polarization and wave polarization have been solved analytically in the ionospheric plasma, taking into account the accepted parameters. Furthermore, the volume and wave polarization were mathematically proven to be connected, and numerical wave polarization values were produced in the ionospheric plasma under the considered parameters. When a magnetic field operates on a medium, it causes the medium to become anisotropic. The wave polarization is ecliptic and the electric field vector does not sweep a circle as understood from analytical solutions when the Earth’s magnetic field and particle collisions are taken into account. There is a real and an imaginary element to the wave’s electric field ratio ( E x / E y = a + ib ). The real and imaginary parts of wave polarization in the x and y planes form the shape of the elliptic structure, and the real component is associated with advancing, while the imaginary part is related to attentiveness. The ionosphere of Earth, all physical parameters, such as refractive index, dielectric structure, and conductivity, have a complicated structure. According to the study, the real part of the polarization of the characteristic wave is related to the absorption coefficient and the imaginary part is proportional to the refractive index of the medium.

Due to the COVID-19 epidemic, human civilization and the corporate world confront unfathomable risks to their continued existence on the planet. People all over the world are losing employment or seeing their incomes diminish due to the COVID-19 virus influence. As a result, its influence has a direct effect on the purchasing ability of consumers. When a customer’s purchasing capability is diminished, his desire for items decreases. Again, retailers or suppliers of deteriorative goods face a risk in this uncertain environment, since deteriorative products have a limited shelf life. They should have an appropriate business strategy in this circumstance to maintain their commercial profession. Taking all of these factors into account, an inventory model is created that incorporates the COVID-19 influence on consumers’ demand for perishable commodities with preservation capability. Customers are granted a partial trade credit term to enable them to sell the items on time. The proposed model is very intricate and not amenable to an analytical solution. Two numerical cases are explored and solved to demonstrate the proposed model’s practical usefulness. The eigenvalues of that numerical example are determined to demonstrate that the Hessian matrix is positive definite, i.e. , to determine the average cost function’s convexity. Finally, we do a post-optimality study to find out how different inventory characteristics affect the best policies.

Since obtaining an analytic solution to some mathematical and physical problems is often very difficult, academics in recent years have focused their efforts on treating these problems using numerical methods. In science and engineering, systems of integral differential equations and their solutions are extremely important. The Taylor collocation method is described as a matrix approach for solving numerically Linear Differential Equations (LDE) by using truncated Taylor series. Integral equations are used to solve problems such as radiative transmission and the oscillation of a string, membrane, or axle. Differential equations can be used to tackle oscillating difficulties. To discover approximate solutions for linear systems of integral differential equations with variable coefficients in terms of Taylor polynomials, the collocation approach, which is offered for differential and integral equation solutions, will be developed. A system of LDE will be translated into matrix equations, and a new matrix equation will be generated in terms of the Taylor coefficients matrix by employing Taylor collocation points. The needed system will be converted to a linear algebraic equation system. Finding the Taylor coefficients will lead to the Taylor series technique.

This current research is about some new optical solitons to the time-fractional integrable generalized (2+1)-dimensional nonlinear Schrödinger (NLS) system with novel truncated M-fractional derivative. The obtained results may be used in the description of the model in fruitful way. The novel derivative operator is applied to study the aforementioned model. The achieved results are in the form of dark, bright, and combo optical solitons. The achieved solutions are also verified by using the MATHEMATICA software. The obtained solutions are explained with different plots. Modified integration methods, Exp a {{\rm{Exp}}}_{a} function, extended ( G ′ ∕ G ) \left(G^{\prime} /G) -expansion, and extended sinh-Gordon equation expansion method are applied to achieve the results. These exact solitons suggest that these methods are effective, straight forward, and reliable compared to other methods.

In this article, we analyze the entropy analysis in unsteady hydromagnetic flow of a viscous fluid over a stretching surface. The energy attribute is scrutinized through dissipation, heat source/sink, and radiation. Furthermore, diffusion-thermo and thermo-diffusion behaviors are analyzed. The physical description of the entropy rate is discussed through the second law of thermodynamics. Additionally, a binary chemical reaction is considered. Partial differential equations are transformed into ordinary ones by adequate variables. Here, we used an optimal homotopy analysis method (OHAM) to develop a convergent solution. The influence of flow variables on velocity, Bejan number, thermal field, concentration, and entropy rate is examined through graphs. The physical performance of drag force, Sherwood number, and temperature gradient versus influential variables is studied. A similar effect holds for velocity through variation of porosity and magnetic variables. An increment in thermal field and entropy rate is noted through radiation. A reverse trend holds for the Bejan number and thermal field through a magnetic variable. An augmentation in the Soret number enhances the concentration. An amplification in drag force is noted through the Forchheimer number. Higher estimation of radiation corresponds to a rise in the heat transfer rate.

The aim of the present study is to simulate double diffusion in a circular cylinder over a rectangular cavity by utilizing incompressible smoothed particle hydrodynamics (ISPH) method. An originality of this study is adopting the ISPH method in simulating double diffusion in a novel domain of a circular cylinder over a rectangular shape occupied by Al 2 O 3 {{\rm{Al}}}_{2}{{\rm{O}}}_{3} – H 2 O {{\rm{H}}}_{2}{\rm{O}} and heterogeneous porous media. The variations of Darcy parameter (Da) between 1 0 − 3 1{0}^{-3} and 1 0 − 5 1{0}^{-5} with two levels of porous media, ( 0 ≤ η 1 = η 2 ≤ 1.5 ) (0\le {\eta }_{1}={\eta }_{2}\le 1.5) , Rayleigh number ( 1 0 3 ≤ Ra ≤ 1 0 5 ) (1{0}^{3}\le {\rm{Ra}}\le 1{0}^{5}) with variable buoyancy ratio parameter ( 0 ≤ N ≤ 2 ) (0\le N\le 2) , solid volume fraction ϕ \phi between 0 and 0.05, and Lewis number ( 10 ≤ Le ≤ 40 ) (10\le {\rm{Le}}\le 40) on the features of heat/mass transport as well as velocity field are discussed. It is found that the homogeneous porous medium reduces the temperature and concentration within a combined cavity. A decrease in Darcy parameter from 1 0 − 2 1{0}^{-2} and 1 0 − 5 1{0}^{-5} suppresses the maximum of a nanofluid velocity by 75% regardless the levels of porous media. An increase in parameters Ra and N enhances the heat and mass transmission, as well as the nanofluid velocity. Adding more concentration of nanoparticles until 5 % 5 \% reduces the nanofluid velocity. The variations of boundary conditions are acting effectively in changing the temperature and concentration circulations within a combined cavity. Besides, the variations of boundary conditions change the maximum of the velocity field by 86.9%.

In this article, natural transform iterative method has been used to find the approximate solution of fractional order parabolic partial differential equations of multi-dimensions together with initial and boundary conditions. The method is applicable without any discretization or linearization. Three problems have been taken as test examples and the results are summarized through plots and tables to show the efficiency and reliability of the method. By practice of a few iterations, we observe that the approximate solution of the parabolic equations converges to the exact solution. The fractional derivatives are considered in the Caputo’s sense.

In this article, we are applying the competing risks model of product from two different lines of production. So, the comparative life test is done under type-II censoring scheme with consideration of only two independent causes of failure. The statistical analysis procedures are developed considering joint sample of production and its life distributed with the Rayleigh lifetime distribution. The point estimation and the corresponding asymptotic confidence interval of the model parameters under maximum likelihood are constructed. Two bootstrap confidence intervals, bootstrap- p p , and bootstrap- t t , are discussed. Also, Bayesian approach to estimate point and credible interval is constructed. The estimation results are discussed through data set analyses. The validity of theoretical results is assessed and compared through Monte Carlo study. Finally, some of the points are reported as a brief comment.

In this article, various exact solutions of the fifth-order variable coefficient KdV equation with higher-order dispersion term are studied. Because of the complexity of the exact solution of the variable coefficient t , it has a certain influence on the tension waves at the fluid interface on the gravity surface. First, the bilinear KdV equation is derived by using the Hirota bilinear method, and four mixed solutions consisting of positive quartic function, quadratic function, exponential function, and hyperbolic function are constructed. Second, the linear superposition principle is used to obtain the resonance multisoliton solution, and two cases are taken as examples to illustrate the study of resonance multi soliton solution. In addition, 3D images and contour images are drawn by mathematical symbol calculation and appropriate parameters, and the process of tension fluctuation is vividly explained by physical phenomena. The results obtained greatly expand the exact solution of the KdV equation in the existing literature and enable us to understand nonlinear dynamical systems more deeply.

Due to their low melting point, low strength, uneven thickness, and sugar and moisture content, tobacco slices are very sensitive to the requirements of cutting parameters. In this article, the CO 2 laser is used to study the specific process parameters in the cutting process of tobacco slices with a moisture content of 13%. The cutting powers and cutting speeds are varied to investigate the effects on the cutting quality of tobacco slices. The result reveals that the lower the cutting speed, the more conducive to the cutting of tobacco slices. And cutting speeds less than 2.5 m/s are preferable to the cutting of tobacco slices. But lower cutting speed means lower cutting efficiency. Meanwhile, the larger the cutting power, the more conducive to the cutting of tobacco slices. However, larger cutting power means larger energy consumption and higher requirements for the laser. Therefore, there is a compromise between cutting speed and cutting power. The preferable cutting power and speed parameters are summarized. The results obtained provide practical guidance for cutting high-quality tobacco slices.

In this article, a new method based on a comprehensive resolution is proposed to evaluate the performance of a common-aperture visible and long-wave infrared (LWIR) imaging system. The influence of the comprehensive resolution on target recognition range is analyzed. Under the condition of common-aperture and a combination of four comprehensive resolutions, the main factors affecting the ratio of target recognition range between the visible imaging system and the LWIR imaging system are discussed. Combined with the constraints of the optical system and the detector, the impact of the comprehensive resolution on the target recognition range is analyzed. The ratio of the target recognition range of the two imaging systems is modeled using the comprehensive resolution of the visible imaging system. The experimental system is built and the experimental results are acquired. The predictive results and experimental results show that when the comprehensive resolution of the visible light imaging system increases, the target recognition ranges of the visible light imaging system and the LWIR imaging system increase, as well as the ratio of the target recognition ranges of the two systems increases.

Aiming at the problems of complex diesel engine cylinder head signals, difficulty in extracting fault information, and existing deep learning fault diagnosis algorithms with many training parameters, high time cost, and high data volume requirements, a small-sample transfer learning fault diagnosis algorithm is proposed in this article. First, the fault vibration signal of the diesel engine is converted into a three-channel red green blue (RGB) short-time Fourier transform time–frequency diagram, which reduces the randomness of artificially extracted features. Then, for the problem of slow network training and large sample size requirements, the AlexNet convolutional network and the ResNet-18 convolutional network are fine-tuned on the diesel engine time–frequency map samples as pre-training models with the transfer diagnosis strategy. In addition, to improve the training effect of the network, a surrogate model is introduced to autonomously optimize the hyperparameters of the network. Experiments show that, when compared to other commonly used methods, the transfer fault diagnosis algorithm proposed in this article can obtain high classification accuracy in the diagnosis of diesel engines while maintaining very stable performance under the condition of small samples.

Two-dimensional electromagnetohydrodynamic behavior of nanofluids through rectangular microchannels is investigated. The combined effects of time-periodic pressure gradients and magnetic fields in terms of the Hall effects on nanofluid flow are considered. Under the Debye–Hückel linearization approximation, the semi-analytic solution of the velocity field is derived by Green’s function method. Furthermore, the semi-analytic solutions of electrokinetic energy conversion (EKEC) efficiency and the streaming potential of nanofluids through the rectangular microchannels are obtained. The variations of the velocity, streaming potential, and EKEC efficiency with the electric double layer thickness K , Hartmann number Ha, Hall parameter m , and dimensionless frequency Ω are shown and briefly discussed.

We numerically investigate and statistically analyze the impact of medium parameters (modulation depth P , modulation factor ω , and gain/loss strength W 0 ) and beam parameters (truncation coefficient a and distribution factor χ 0 ) on the propagation characteristics of a cosh-Airy beam in the Gaussian parity-time (PT)-symmetric potential. It is demonstrated that the main lobe of a cosh-Airy beam is captured as a soliton, which varies periodically during propagation. The residual beam self-accelerates along a parabolic trajectory due to the self-healing property. With increment in P , the period of a trapped soliton decreases almost monotonically, while the peak power of a trapped soliton increases monotonically. With the increase in ω or decrease in the absolute value of W 0 , the period and peak power of a trapped soliton decrease rapidly and then almost remain unchanged. Moreover, it is indicated that the period of a trapped soliton remains basically unchanged no matter a and χ 0 increase or decrease. The peak power of a trapped soliton increases with increment of a , but the peak power of a trapped soliton stays relatively constant irrespective of variation in χ 0 .

In this work, we investigate a generalized Kadomtsev–Petviashvili equation with variable coefficients and self-consistent sources in plasma and fluid mechanics. The multiple rogue wave solutions, including 1-, 3-, and 6-order rogue waves, are presented by three different functions under a nonlinear transformation. Based on the Hirota bilinear method and a more complex assumption, new lump solutions are constructed, which have not been seen in other literature. The dynamic properties of the obtained results are illustrated graphically.

At present, image analysis and digital core are the main approaches for porous media reconstruction modeling, and they are both based on the real pore skeleton physical structure of porous media. However, it is difficult to reconstruct the reservoir and seepage characteristics of the real samples because of the limitations of accuracy in characterization techniques (imaging). In order to solve this problem and break through the barriers caused by the lack of accuracy, Spin-echo serial peripheral interface sequence of low field nuclear magnetic resonance is used to test the saturated water rock core with spatially resolved T 2 distributions. Based on the experimental results of 1D T 2 distributions, a novel method for fine reconstruction modeling of porous media is proposed, and the porous media model reconstructed by this new method better reproduces the reservoir and seepage characteristics of the original samples. Taking some of the tested porous media cores (P58 and Y75) as examples, representative elementary volume (REV)-lattice Boltzmann method (LBM) is used to simulate the flow field. Ensuring that the error of standard case is only 0.36% when multi-relaxation time REV-LBM is used, the distribution of porosity and permeability have been calculated and compared with the experimental data. The overall permeability error of the reconstructed porous media model is only 6.15 and 7.60%, respectively. Furthermore, the porosity and permeability error of almost all measuring points can be maintained within 3 and 8%. In addition, this method improves the efficiency of the existing reconstruction modeling methods, reduces the test cost, and makes the reconstruction modeling of porous media easier to operate, which has promising development prospects.

Human society is entering Industry 4.0. Engineering systems are becoming more complex, which increases the difficulties in maintenance support work. Maintenance plays a very important role in the entire life cycle of a system, and in reality, maintenance is not always perfect, and its maintenance degree is between good as new and bad as old, which should be considered in the maintenance strategy. Under the framework of two-dimensional warranty, this work proposes an optimal two-dimensional block replacement strategy based on the minimum expected warranty cost. Two-dimensional block replacement maintenance is imperfect maintenance. The failure rate reduction method is used to describe the maintenance effect of two-dimensional block replacement. In case analysis, the grid search algorithm, genetic algorithm, particle swarm optimization algorithm, and improved salp swarm algorithm (SSA) are used to find the optimal warranty scheme for the laser module. The improved SSA can converge faster and find a warranty scheme that makes the warranty cost lower. Therefore, managers can use these results to reduce costs and get a win-win extended warranty cost. Rationalization suggestions are put forward for managers to make maintenance decisions through comparative analysis and sensitivity analysis.

The natural streamflow of the River is encouraged to forecast through multiple methods. The impartiality of this study is the comparison of the forecast accuracy rates of the time-series (TS) hybrid model with the conventional model. The behavior of the natural monthly statistical chaotic streamflow to use in the forecasting models has been compiled by projecting two distinguished rivers, the Indus and Chenab of Pakistan. Therefore, this article is based on the monthly streamflow forecast analysis that has been reported using the group method of data handling with wavelet decomposition (WGMDH) as a new forecasting attribute. Discrete wavelets decompose the perceived data into sub-series and forecast hydrological variables; these fittingly have been endorsed as inputs in the hybrid model. The forecast efficiency and estimations of the hybrid model are measured by the appropriate statistical techniques such as mean absolute error (RME), root mean square error (RMSE), and correlation coefficients ( R ) and compared to the group method of data handling (GMDH), least-square support vector machine and artificial neural network conventional models. The comparative analysis shows that the hybrid WGMDH model is more stable and more potent for forecasting river flow than other predictive models and significantly proved that the hybrid model is a robust alternate forecasting tool for TS data sets.

Hybrid pencil beam model (HPBM) based on photon characteristic line algorithm has been presented to get accurate three-dimensional (3D) dose distribution for lung radiotherapy in small fields. In the model, we introduced a scattering factor to accurately describe the transport behavior of scattered photons and secondary electrons, combined with the equivalent depth correction and the weighted density correction. The pencil beam kernels of heterogeneous lung phantoms were redefined by the scattering factor and depth dose for a reference field by photon characteristic line algorithm. Subsequently, the 3D dose distribution in lung phantoms with density of 0.1, 0.26, and 0.4 g/cm 3 , was calculated by the Finite-size pencil beam algorithm in five regular fields and an irregular field for 6 MV photon beam. The dose distributions obtained by the HPBM are in agreement with those obtained by the MC simulations, with a relative error of less than 3% in most of the cases. However, there are apparent discrepancies at media interfaces and lung anterior portion. Moreover, at media interfaces, relative dose errors of the two methods decrease with the increase in field size and lung density. The depth range in which relative errors is greater than 3% increases with the increase in field size at lung anterior portion. In these examples, maximum relative errors are between 5 and 29%. Nevertheless, it is shown that the HPBM based on photon characteristic line algorithm has potential research values in lung dose calculation under conditions of small fields.

Recently, Khajiyeva et al . (2018) studied the dynamics of surface wave propagation in a pre-stressed incompressible half-space when accompanied by both vertical and tangential loads. In this study, however, we extend the work of Khajiyeva et al . to include the presence of a coating layer above the half-space, upon which the loads are acted. Moreover, we prescribe sufficient perfect continuity conditions between the two layers, resulting in an inhomogeneous composite structure. Furthermore, related effective boundary conditions within the long-wave assumption are acquired for the model through the application of the asymptotic approximation method. Finally, approximate uncoupled pseudo-differential equations are derived on the surface, thereby admitting all the results of Khajiyeva et al . as limiting cases of concern.

Radiation has been used in a variety of different fields since its discovery. It is very important in medial sector for both diagnosis and also for treatment. In this study, the radiation dose rate emitted to the environment after radiopharmaceutical injection was determined using patients undergoing bone scintigraphy imaging. Radiation dose rate measurements were performed at different distances from the patient and at different levels of the patient. Measurements were done at different times to determine the relationship between radiation dose rate and time. The radiation dose rate emitted by the patient was measured after an average of 10.21, 42.36, and 76.28 min of injection. In order to see the relationship between radiation dose rate and distance, measurements were done at 25, 50, 100, and 200 cm distance from the patient. The measured average radiation dose rate at 1 m distance from the patients’ chest level and 10.21 min after radiopharmaceutical injection was 16.27 μSv h −1 . Then, the average radiation dose rate decayed down to 13.65 μSv h −1 after 42.36 min, while the measured average radiation dose rate after 76.28 min was lower as 12.41 μSv h −1 at 100 cm from patient’s chest level.

Lie symmetry analysis (LSA) is one of the most common, effective, and estimation-free methods to find the symmetries and solutions of the differential equations (DEs) by following an algorithm. This analysis leads to reduce the order of partial differential equations (PDEs). Many physical problems are converted into non-linear DEs and these DEs or system of DEs are then solved with several methods such as similarity methods, Lie Bäcklund transformation, and Lie group of transformations. LSA is suitable for providing the conservation laws corresponding to Lie point symmetries or Lie Bäcklund symmetries. Short pulse equation (SPE) is a non-linear PDE, used in optical fibers, computer graphics, and physical systems and has been generalized in many directions. We will find the symmetries and a class of solutions depending on one-parameter ( ε ) obtained from Lie symmetry groups. Then we will construct the optimal system for the Lie algebra and invariant solutions (called similarity solutions) from Lie subalgebras of generalized SPE.

The dissociation of nitrogen trifluoride (NF 3 ) is an important topic of study because the molecule is a highly dangerous greenhouse gas that can persist in the atmosphere for 740 years. In this study, changes in the geometry, orbital energy, spectral properties, and dissociation properties of NF 3 when an external electric field was applied were studied by density functional theory. Results show that when the strength of the electric field was increased, the N–3F bond length became longer until it broke, and the energy gap decreased gradually. The dissociation barrier in the potential energy curve gradually decreased with the increase in the electric field strength. When the applied electric field reached 0.05 a.u., the dissociation barrier disappeared, indicating that under the action of a strong applied electric field, NF 3 is degraded because of fracture of the N–3F bond. When the application of the electric field was continued, the potential barrier disappeared and dissociation occurred when the N–4F bond was scanned. The stepwise dissociation of nitrogen trifluoride molecules occurred under an electric field intensity of 0.05 a.u. The concerted dissociation of the N–3F and N–4F bonds occurred at an electric field intensity of 0.09 a.u. When the electric field direction was in the negative direction of the z -axis, the NF 3 dissociated but no concerted dissociation occurred. These results offer insight into the degradation mechanism under an applied electric field.

This demonstration of study focalizes the melting transport and inclined magnetizing effect of cross fluid with infinite shear rate viscosity along the Skan-Falkner wedge. Transport of energy analysis is brought through the melting process and velocity distribution is numerically achieved under the influence of the inclined magnetic dipole effect. Moreover, this study brings out the numerical effect of the process of thermophoresis diffusion and Brownian motion. The infinite shear rate of viscosity model of cross fluid reveals the set of partial differential equations (PDEs). Similarity transformation of variables converts the PDEs system into nonlinear ordinary differential equations (ODEs). Furthermore, a numerical bvp4c process is imposed on these resultant ODEs for the pursuit of a numerical solution. From the debate, it is concluded that melting process cases boost the velocity of fluid and velocity ratio parameter. The augmentation of the minimum value of energy needed to activate or energize the molecules or atoms to activate the chemical reaction boosts the concentricity.

This article is directed to analyze the transfer of mass and heat in a generalized Maxwell fluid flow unsteadily on a vertical flat plate oscillating in its respective plane and heated exponentially. It explains the transfer of mass and heat using a non-integer order derivative usually called a fractional derivative. It is a generalization of the classical derivatives of the famous Maxwell’s equation to fractional non-integer order derivatives used for one-dimensional flow of fluids. The definition given by Caputo–Fabrizio for the fractional derivative is used for solving the problem mathematically. The Laplace transform method is used for finding the exact analytical solution to a problem by applying it to a set of non-integer order differential equations that are dimensionless in nature. These equations contain concentration, temperature, and velocity equations with specific initial and boundary conditions. Solutions of the three equations are graphically represented to visualize the effects of various parameters, such as the radiation parameter (Nr), the thermal Grashof number, the fractional parameter ( α ), the mass Grashof number, Prandtl effective number, Schmidt number, Prandtl number, the chemical reaction ( η 2 ) ({\eta }_{2}) , mass, and the temperature during fluid flow.

Nanofluid has emerged as a remarkable heat and mass transfer fluid due to its thermal characteristics. Despite this, continuing research is required to address problems in real applications and offer a solution for controlling transfer analysis. Therefore, in this study, the authors intend to model (Ginzburg–Landau equation) and analyze the two-dimensional nanofluid convection with gravity modulation. The perturbed analysis is adapted to convert the leading equations into Ginzburg–Landau equation. Lower amplitude ( δ \delta values from 0 to 0.5) values are taken since they influence transfer analysis. The values of Pr are considered as 0 to 2 to retain the local acceleration term in the system of equations. A lower amount of frequency of modulation ( Ω \Omega values from 0 to 70) is sufficient to enhance the heat and mass transfer rates. It is found that g-jitter and concentration Rayleigh numbers control the stability of the system. The Prandtl number and the amplitude of modulation enhance nano-heat and nano-mass transfer. This shows a destabilizing effect of modulation on nano-convection. Also the nano-Rayleigh number Rn has a dual nature on the kinetic energy transfer for positive and negative signs. A comparison is made between modulated and unmodulated systems, and it is found that the modulated systems influences the stability problem than the unmodulated systems. Finally, it is found that g-jitter influences effectively to regulate the transport process in the layer.

Strip optical waveguides were realized in Yb 3+ -doped silicate glass with ultrashort pulse laser ablation assisted He + ion implantation. Planar waveguides were first prepared near the glass surface by He + ion implantation (450 keV + 500 keV + 550 keV), followed by annealing at 260℃. After that, under the processing parameters of 3 μJ energy and 50 μm/s ablation velocity, two parallel tracks with separation of 15, 20, and 25 μm were, respectively, inscribed on the sample, which confine the light in lateral direction to form a strip waveguide. The near-field intensity measurement indicates that the strip waveguides maintain the single-mode propagation characteristics with 976 nm laser injection, and present the multi-mode characteristics with 632.8 nm laser injection, showing that the guided modes are well supported in the strip waveguides. The minimum propagation loss of strip waveguide is 1.35 dB/cm. Fluorescence emission spectra indicate that the gain properties of waveguide core were maintained well after waveguide preparation, revealing that the strip waveguide device in Yb 3+ -doped silicate glass has the potential to become an active device as waveguide laser or waveguide amplifier.

This study sought to identify the most accurate forecasting models for COVID-19-confirmed cases, deaths, and recovered patients in Pakistan. For COVID-19, time series data are available from 16 April to 15 August 2021 from the Ministry of National Health Services Regulation and Coordination’s health advice portal. Descriptive as well as time series models, autoregressive integrated moving average, exponential smoothing models (Brown, Holt, and Winters), neural networks, and Error, Trend, Seasonal (ETS) models were applied. The analysis was carried out using the R coding language. The descriptive analysis shows that the average number of confirmed cases, COVID-19-related deaths, and recovered patients reported each day were 2,916, 69.43, and 2,772, respectively. The highest number of COVID-19 confirmed cases and fatalities per day, however, were recorded on April 17, 2021 and April 27, 2021, respectively. ETS (M, N, M), neural network, nonlinear autoregressive (NNAR) (3, 1, 2), and NNAR (8, 1, 4) forecasting models were found to be the best among all other competing models for the reported confirmed cases, deaths, and recovered patients, respectively. COVID-19-confirmed outbreaks, deaths, and recovered patients were predicted to rise on average by around 0.75, 5.08, and 19.11% daily. These statistical results will serve as a guide for disease management and control.

To improve the photoelectric test accuracy of moving objects, in this study, the speed attenuation caused by air resistance was introduced into the double-N six-light-screen test system, and the test system was theoretically analyzed through oblique incidence with field experiment for verification. It was found in the study that the optimal test values for yaw angle, pitch angle, axial speed, and distance could be obtained by selecting the pulse time origin at the center of two light screen groups. In addition, mud pellets were used for field experiments to effectively verify the simulation results. In a new model, the test accuracy of yaw angle and pitch angle was greatly improved when compared with traditional processing methods, but the laws of error distribution remained almost unchanged. The error of axial speed showed monotonicity as affected by the pitch angle. At the same time, the error of test distance remained symmetric with the improved accuracy, thereby meeting the statistical test requirements for small-volume moving objects.

With the rise of graphene, other elemental 2D materials have received a massive increase in interest in recent years. However, while theoretical models of free-standing materials predict exotic properties, often outshining those of graphene, the experimental field struggles with the synthesis of such materials. Epitaxial growth has become the main method used in experiments, as the consensus in the scientific community is that such materials require a stabilizing support. In this context, a substrate material suitable for supporting a 2D layer while preserving its topological properties is a key factor in the process. In this review article, our focus is directed to substrates for an elemental topological 2D material from group IV – stanene. We present the current state of the experimental field and give an outlook on future possibilities investigated in density functional theory (DFT) calculations.

Photovoltaic (PV) systems are an excellent solution to meet energy demand and protect the global environment in many cases. With the increasing utilization of the PV system worldwide, there is an increasing need for simulation tools to predict the PV system’s performance and profitability. This research includes testing and comparison of PV tools: photovoltaic geographical information system (PVGIS), PVWatts, SolarGIS, RETScreen, BlueSol, PVsyst, HelioScope, PV*SOL, Solarius PV, Solar Pro, PV F-Chart, PolySun, solar advisor model (SAM), and hybrid optimization model for electric renewables (HOMER), based on experimental data obtained from fixed on-grid 2 kW p PV system in 2019. The PV system is part of a research project related to the examination of the PV system operation in real climatic conditions in Niš. This research investigates the most appropriate PV software for PV systems design by testing the most commonly used PV tools. It was accomplished by comparing experimental data obtained by a 2 kW p PV system in Niš and estimated data obtained from different PV tools. The study shows that annually, the experimentally measured average daily solar irradiation on the inclined plane was 5,270 Wh/m 2 /day, and the lowest deviation of the simulation results compared to experimental measurements was obtained by SolarPro. Total annual electricity production from the given system was 2455.621 kW h, and the lowest deviation of the simulation results compared to experimental measurements was obtained by PVGIS. By analyzing and publishing the actual solar irradiation and PV power output data, this study could help researchers to increase the PV systems modeling accuracy.

The Debye–Scherrer (DS) technique is a common technique for determining spacings in atomic layers by X-ray diffraction. The spacings of the atomic layers are proportional to the macroscopic stress in the radiated area. When a crystalline powder is irradiated with X-rays, the diffracted X-rays produce a ring that photographic films detect. Afterward, the film is developed to reveal the rings. Earlier, this procedure took lots of time. With upcoming multiple wavelength anomalous dispersion-detectors, a very sensitive area detector, DS rings can be detected and analyzed in minutes. This allows for the rapid determination of residual stresses prior to inspection in a production environment. Additional information from the intensity distribution within the ring can be obtained. A description of the new technique is given.

The radial motion of an electron in a Coulomb attracting field based on a new theory of the interaction of a particle with an electromagnetic field is studied. It is shown that the electron can perform radial oscillations due to a repulsive force that exists in the vicinity of the center and prevents the electron from approaching the center. This concept of a previously unknown repulsive force significantly shifts the paradigm of the interaction of a charge with an electromagnetic field. A laboratory experiment is proposed to test the new phenomenon.

The fundamental objective of this article is to find exact solutions to the stochastic fractional-space Allen–Cahn equation, which is derived in the Itô sense by multiplicative noise. The exact solutions to this equation are required since it appears in many discipline areas including plasma physics, quantum mechanics and mathematical biology. The tanh–coth method is used to generate new hyperbolic and trigonometric stochastic and fractional solutions. The originality of this study is that the results produced here expand and improve on previously obtained results. Furthermore, we use Matlab package to display 3D surfaces of analytical solutions derived in this study to demonstrate the effect of stochastic term on the solutions of the stochastic-fractional-space Allen–Cahn equation.

This article aims to address the exact solution of the prestigious partial differential equation, namely, a double dispersive equation. Here, we are obtaining some new traveling wave solutions of the double dispersive equation with the more general mathematical technique, which is a direct algebraic extended method. This proposed technique is more general and integrated. The obtained solutions contain dark, bright, dark–bright, singular, periodic, kink, and rational function solutions. More illustration of traveling wave solutions of the double dispersive equation is given by plotting the two- and three-dimensional graphs with the suitable selection of parameters. This graphical presentation of solutions identifies the pattern of wave propagation. The acquired consequences are new and may play a significant role to examine the physical phenomena of wave propagation, where this model is used.

Usually, to find the analytical and numerical solution of the boundary value problems of fractional partial differential equations is not an easy task; however, the researchers devoted their sincere attempt to find the solutions of various equations by using either analytical or numerical procedures. In this article, a very accurate and prominent method is developed to find the analytical solution of hyperbolic-telegraph equations with initial and boundary conditions within the Caputo operator, which has very simple calculations. This method is called a new technique of Adomian decomposition method. The obtained results are described by plots to confirm the accuracy of the suggested technique. Plots are drawn for both fractional and integer order solutions to confirm the accuracy and validity of the proposed method. Solutions are obtained at different fractional orders to discuss the useful dynamics of the targeted problems. Moreover, the suggested technique has provided the highest accuracy with a small number of calculations. The suggested technique gives results in the form of a series of solutions with easily computable and convergent components. The method is simple and straightforward and therefore preferred for the solutions of other problems with both initial and boundary conditions.

The current work is devoted to introduce a novel thermoelastic heat conduction model where the Moore-Gibson-Thompson (MGT) equation describes the heat equation. The constructed model is characterized by allowing limited velocities of heat wave propagation within the material, consistent with physical phenomena. The Green–Naghdi Type III model is improved by introducing the delay factor into the modified Fourier law. Also, from the presented model, some other models of thermoelasticity can be derived at specific states. Based on the suggested model, an infinite orthotropic material with a cylindrical hole exposed to time-dependent temperature variation was studied. It has also been considered that the coefficient of thermal conductivity varies with temperature, unlike in many other cases where this value is considered constant. The viscoelastic material of the investigated medium was assumed to be of the Kelvin–Voigt type. The Laplace transform method provides general solutions to the studied field variables equations. The effects of viscosity and thermal variability parameters on these fields are discussed and graphically presented. In addition, the numerical results were presented in tables, and a comparison with previous models was made to ensure the accuracy of the results of the proposed model.

In many regions across the world, hepatitis B virus (HBV) infection is still endemic and the transmission rate is much greater than majority of the known epidemic diseases. Numerous mathematical models (utilizing various differential operators) have been put forth over the past 20 years to understand the transmission mechanism of HBV in various nations and geographical areas. In this manuscript, an epidemic model with various novelties for capturing the dynamic of HBV while utilizing Caputo–Fabrizio fractional differential operator with asymptomatic carriers and vaccination effects is introduced. Initially, the model is formulated by using the ordinary derivative, and afterward, the fractional differential operator is applied to transform the model into arbitrary-ordered derivative. A few basic mathematical properties for the proposed integer-ordered model is presented. The existence of solution to the problem and its uniqueness of the fractional order model are established by transforming the problem into integral equations and then applying the standard results of fixed point theory. For boundedness and positivity of model’ solution is elaborated utilizing the techniques of fractional calculus. It is too much important to validate the theoretical findings through simulations; therefore, the solution curves of the model under consideration are displayed by using the well-known approach called the Mittag-Leffler. To show the behavior of the order of the operator on the dynamics of the disease, various graphical illustrations are presented at the end of the manuscript. By comparing the findings of the present study with the available literature, it is observed that fractional derivative is better to use than integer-order operator for capturing the realistic scenario of the disease.

SiC foam ceramics are extensively used in numerous industrial applications that require high-temperature conditions. They can be used as thermal insulation, structural catalyst supports and energy storage materials. In this article, effective thermal conductivity of SiC foam ceramics at high temperature is studied by steady plane heat source method. This research aims to investigate the variations of effective thermal conductivity with pore density, stacking thickness, heat source temperature, and pore arrangement structure of foam ceramics. By a comparison of effective thermal conductivities of various pore density ceramic sheets, the experimental results show that the effective thermal conductivity of foam ceramics decreases with the increase of the pore density and stacking thickness. The effective thermal conductivity of the foam ceramics increases significantly when the heat source temperature is more than 200°C. For modular SiC foam ceramics, increasing the average pore density and sudden change of the pore density between ceramic sheets are not conducive to the increase of the effective thermal conductivity.

This article deals with a new modified heat conduction model with fractional order that includes the Caputo–Fabrizio differential operator (CF) and the thermal relaxation time. This new approach to the CF fractional derivative has attracted many researchers because it includes a nonsingular kernel. The nonlocal theory proposed by Eringen has also been applied to demonstrate the effect of scale-dependent thermoelastic materials. The problem of thermal isotropic semi-infinite space is addressed as an application of the presented model. The medium is exposed to regularly changing heat sources and is initially placed in a continuous external magnetic field. The system of governing equations was expressed in the field of the Laplace transform, and the problem in this field was solved by the state-space operation. The inverse of the transformed expressions of physical quantities is found numerically using Zakian’s algorithm. The effects of the nonlocal parameter, the fractal order parameter, and the magnetic field were graphically presented and analyzed in detail. Some of the previous investigations were extracted in some special cases.

To study the flow and heat transfer characteristics of diesel particulate filter wall porous media, Lattice Boltzmann Method (LBM) is used to simulate and analyze different structures in this article. On studying the heat transfer and flow characteristics of regular structures such as parallel and staggered structures, it is proved that the distribution of porous media structure has an effect on the heat transfer and flow characteristics. The effects of different structure distributions on the flow and heat transfer characteristics are analyzed by studying the complex structures such as random structure and the structure of Quartet Structure Generation Set (QSGS). The influences of different fiber diameters on the parameters under the parallel arrangement, the staggered arrangement, and the random arrangement is considered. The flow and heat transfer characteristics of the QSGS structure and Sierpinski carpets structure are also considered. Under the same porosity, different fiber diameters have effect on dimensionless permeability coefficient, pressure gradient, and filtration efficiency. The different structures of porous media affect the temperature and pressure distribution. For the relatively complex structure, the flow resistance is greater. The increase in Re will reduce the temperature gradient, and with the increase in Re, the flow in the structure will be more uniform.

This work solves the problem of thin-film withdrawal and drainage of a steady incompressible couple stress fluid on the outer surface of a vertical cylinder. The governing equations for velocity and temperature distributions are subjected to the boundary conditions and solved with the help of homotopy analysis method. The obtained expressions for flow profile, temperature profile, average velocity, volume flow rate, and shear stress confirmed that the thin-film flow of couple stress fluid highly depends on involved parameters say Stokes number S t , vorticity parameter λ , couple stress parameter η , and Brinkman number Br presented in the graphical description as well.

A mathematical model representing the temporal dynamics of hepatitis B virus (HBV) is discussed in this research work. This is based on the asymptomatic carriers and symptomatic individuals keeping in view the characteristics of the disease. We also incorporate the vaccination parameter to vaccinate susceptible individuals. Moreover, we use fractional calculus to extend the model to its associated fractional-order. For this, we particularly use the fractional operator of the Caputo-Fabrizio type to fractionalize the proposed model. First, the model formulation has been derived in classic order and then extended to its associated fractional-order version for generalization. The model equilibria was calculated, and the basic reproductive number was found. Then we will discuss the existence with properties of the uniqueness of the proposed fractional version of the model that is under consideration. The positivity with boundedness is shown to investigate that the considered model is feasible biologically as well as mathematically. Finally, we use the Mittag–Leffler approach to visualize the model of fractional-order and to support the results carried out in the theocratical part. We also demonstrate the solution curves for different values of the fractional parameter to differentiate between integer-order and fractional-order on the disease transmission.

Our key objective in the present work is to elaborate the concept of activation energy in chemically reactive flow with the help of modeling and computation. The model investigated is fluid flow over a vertical cylinder in the porous medium with chemical reaction and radiation effect. The similarity transform converted the resulting constitutive equations and partial differential equations (PDEs) into ordinary differential equations (ODEs). The resulting non-linear momentum, heat transfer, and mass transfer coupled equations are computed with the Range–Kutta–Fehlberg method. Both assisting and non-assisting buoyant flow conditions are considered, and observed numeric solutions vary with the transport properties. Characteristics of momentum, heat, and concentration under the applied boundary conditions are analyzed. In addition, the increment in activation energy parameters boosts the Lorentz force and mass transfer rate.

In the present study, the ion-acoustic solitary wave solutions for Kadomtsev–Petviashvili (KP) equation, potential KP equation, and Gardner KP equation are constructed. The nonlinear KP equations are studying the nonlinear process of waves without collisions plasma and having non-isothermal electrons and cold ions. Two-dimensional ion-acoustic solitary waves (IASWs) in magnetized plasma are consisting of electrons and ions. We obtained the ion-acoustic solitary wave solutions same as dark and bright, kink and anti-kink wave solitons. The physical phenomena of various structures for IASWs are represented graphically with symbolic computations. These results are more helpful in the development of soliton dynamics, quantum plasma, dynamic of adiabatic parameters, fluid dynamics, and industrial phenomena.

Antibiotic resistance is becoming one of the threats to global health. This crisis has been attributed to the over-the-counter and overuse of antibiotics leading bacteria to gain the ability to resist and survive even in the presence of antimicrobial agents. Escherichia coli ( E. coli ) is one of the major gram-negative bacteria that are the representative indicators of antibiotic resistance. One of the mechanisms of gaining antibiotic resistance is the ability of E. coli to gain the production of extended-spectrum beta-lactamases (ESBL). In this study, Near East University Hospital data from 2016 to 2019 were used to study the dynamics of ESBL-producing ( ESBL + {\text{ESBL}}^{+} ) and non-ESBL-producing ( ESBL − {\text{ESBL}}^{-} ) E. coli infections by using a mathematical model. In our study, the aim was to evaluate the distribution of infections caused by resistant E. coli strains in later years and to increase the success of treatment in patients infected with E. coli by reducing the problem of antibiotic resistance. By using the mathematical model and data of the patients, basic reproduction number ( R 0 ) values were calculated to study epidemiologic dynamics of the disease. The R 0 E − {R}_{0}^{{E}^{-}} and R 0 E + {R}_{0}^{{E}^{+}} values for ESBL − {\text{ESBL}}^{-} and  ESBL +   {\text{ ESBL}}^{+}\text{ } E. coli infections were calculated, respectively. According to the model and the data used within the study, it was calculated that R 0 E − {R}_{0}^{{E}^{-}} to be 1,266,403 and R 0 E + {R}_{0}^{{E}^{+}} to be 2,096,747. Since the values for R 0 E − {R}_{0}^{{E}^{-}} and R 0 E + {R}_{0}^{{E}^{+}} were equal or greater than 1, this suggests that currently the ESBL − \hspace{.25em}{\text{ESBL}}^{-} and  ESBL +   {\text{ ESBL}}^{+}\text{ } E. coli infections are in epidemic character for Cyprus. Furthermore, when simulation analyses were carried out for the model, it was predicted that in 2042 the ESBL − {\text{ESBL}}^{-} and  ESBL + {\text{ ESBL}}^{+} E. coli infection trends will equalize. After 2042, the ESBL −   {\text{ESBL}}^{-}\text{ } E. coli infections will indicate a descending pattern whereas  ESBL +   {\text{ ESBL}}^{+}\text{ } E. coli infection will increase constantly.

In the present article, the first step is devoted to develop some results about existence and uniqueness of solution to a general problem of fractional order partial differential equations (FPDEs) via classical fixed point theory. In the second step, a novel technique is used to handle the semi-analytical approximate solution for the considered general problem. Then, we extend the said result to fractional order partial Benney equations (FOPBEs) of the second and third order, which are special cases of the general problem we considered. We study the proposed problem under the Caputo-Febrizo fractional derivative (CFFD). With the help of the proposed method, we derive a series type approximate (semi-analytical) solution. Some numerical interpretations and visualizations are also given.

In this article, the solutions of higher nonlinear partial differential equations (PDEs) with the Caputo operator are presented. The fractional PDEs are modern tools to model various phenomena more accurately. The residual power series method (RPSM) is used for the solution analysis of fractional partial differential equations (FPDEs), which has direct implementation for the solutions of fractional partial differential equations. In this work, the solutions to a few nonlinear FPDEs are handled by the proposed technique. The general and particular schemes of RPSM are constructed and implemented successfully. The fractional solutions of PDEs have provided many useful dynamics of the targeted problems. The RPSM results for both integer and fractional-order FPDEs are further explained and elaborated by using graphs and tables. It is observed that the higher accuracy of RPSM is achieved with fewer calculations. Graphs and tables for fractional-order solutions are presented, which confirm the convergence phenomena of fractional solutions toward integer order solutions of each problem. The suggested method can be extended to the solutions of other nonlinear fractional partial differential equations.

This article deals with modelling the Wi-Fi wave field, which is not visible to the naked eye, into a mathematical structure for assigning colours to observe the wave strength change compared to the source layout’s location correlation of obstacles in the survey environment. The shape function is used as a tool in modelling combined with finite sample measurement data to determine the basic parameters of the shape function. These will allow the wave field to be modelled using two techniques: the theoretical shape function and the experimental shape function. The measuring tool used in the article is the Wi-Fi Analyzer App that runs on a smartphone. The colour-assigned representation of an invisible field such as a wave will help select the signal maximal or minimization positions most beneficial to the user. The proposal is easily applied in the wave field and other quantities such as temperature, light, and concentration with similar techniques.

In this article, we extend the generalized invexity and duality results for multiobjective variational problems with fractional derivative pertaining to an exponential kernel by using the concept of weak minima. Multiobjective variational problems find their applications in economic planning, flight control design, industrial process control, control of space structures, control of production and inventory, advertising investment, impulsive control problems, mechanics, and several other engineering and scientific problems. The proposed work considers the newly derived Caputo–Fabrizio (CF) fractional derivative operator. It is actually a convolution of the exponential function and the first-order derivative. The significant characteristic of this fractional derivative operator is that it provides a non-singular exponential kernel, which describes the dynamics of a system in a better way. Moreover, the proposed work also presents various weak, strong, and converse duality theorems under the diverse generalized invexity conditions in view of the CF fractional derivative operator.

This article aims to conduct a numerical investigation of phenomena induced by gas expansion in chemical propulsion nozzles. A numerical simulation of full-scale flat convergent-divergent nozzle geometry using the finite volume method on structured meshes is performed to predict the change in the convergent geometry on the boundary layer separation resulting from a shock/shock and shock/boundary layer. Two turbulence models are tested, namely, the k − ε and k − ω shear-stress transport (SST) models. Three steps are considered to achieve this work. First, 10 numerical schemes are tested to select the accurate one. The findings of the first step are used to predict the boundary layer separation in a supersonic overexpanded nozzle. The available experimental data from the NASA Langley Research Center are used to validate the results. The third step concerns investigating the impact of the convergent geometric profile on the downstream flow of the nozzle. The obtained results are analyzed and compared with the experimental data. These results show that convergent geometry may cause the formation of different shock structures and different points of flow separation and modifies several parameters of the flow and nozzle performance downstream the throat. The findings indicated that the convergent profile must be considered during the design phase when focusing on the problem of boundary layer separation in the supersonic overexpanded regime nozzles.

Several numerical techniques for solving initial value problems arise in physical and natural sciences. In many cases, these problems require numerical treatment to achieve the required solution. However, in today’s modern era, numerical algorithms must be cost-effective with suitable convergence and stability features. At least the fifth-order convergent two-step optimized hybrid block method recently proposed in the literature is formulated in this research work with its variable stepsize approach for numerically solving first- and higher-order initial-value problems in ordinary differential equations. It has been constructed using a continuous approximation achieved through interpolation and collocation techniques at two intra-step points chosen by optimizing the local truncation errors of the main formulae. The theoretical analysis, including order stars for the relative stability, is considered. Both fixed and variable stepsize approaches are presented to observe the superiority of the latter approach. When tested on challenging differential systems, the method gives better accuracy, as revealed by the efficiency plots and the error distribution tables, including the machine time measured in seconds.

It is a well-known fact that functional effects like relaxation and retardation of materials, and heat transfer phenomena occur in a wide range of industrial and engineering problems. In this context, a mathematical model is developed in the view of Caputo fractional derivative for Oldroyd-B nano-fluid. Nano-sized particles of copper (Cu) are used to prepare nano-fluid taking water as the base fluid. The coupled non-linear governing equations of the problem are transformed into dimensionless form. Finite difference scheme is developed and applied successfully to get the numerical solutions of deliberated problem. Influence of different physical parameters on fluid velocity profile and temperature profile are analyzed briefly. It is observed that for increasing values of fractional parameter ( α ), fluid velocity increased, but opposite behavior was noticed for temperature profile. Nusselt number (Nu) decayed for advancement in values of heat source/sink parameter ( Q 0 ), radiation parameter (Nr), volume fraction parameter of nano-fluid ( ϕ ), and viscous dissipation parameter (Ec). Skin friction ( C f ) boosts for the increase in the values of magnetic field parameter (Ha). It can also be noticed that the extended finite difference scheme is an efficient tool and gives the accurate results of discussed problem. It can be extended for more numerous type heat transfer problems arising in physical nature with complex geometry.

The load rate of asynchronous motors is low, the operation efficiency is low, and the waste of electric energy is very serious. Therefore, a voltage regulation and electricity saving method for asynchronous motors based on fuzzy control theory is proposed. According to the principle of voltage regulation and power saving of asynchronous motor, the stator current and its variation of are selected as input variables, the deviation of current variation is selected as output variable, and a two-dimensional fuzzy control algorithm model is constructed. Fuzzy control theory is used for voltage regulation and power saving of asynchronous motors. The simulation results show that the proposed method is based on fuzzy control theory for voltage regulation and electricity saving of asynchronous motors; after the voltage regulation and electricity saving control, the phase current of the motor is lower, and the active power and reactive power of the motor are reduced. The power factor of the motor is higher, and the power-saving effect is remarkable.

The simple instalment of mobile charging piles benefits for its convenient layout, while dynamic arrangements of those charging piles through mobile mode make up for the insufficient number of fixed charging piles, which meets the growing charging demand under the increasing popularity of electric vehicles. According to the application requirements of mobile charging piles, CATIA software was used to model the structure, of which strength and reliability were analysed under four load conditions. Our results have demonstrated that the maximum deformation value of the structure is 3.07 mm, and the maximum stress is 134.41 MPa, which is within the safety range of the selected materials. In addition, the gravity centre of the charging pile is located at the bottom of the structure, and thus the stability meets the requirements. Taken together, our research provided a beneficial reference for future engineering practice.

The objective of this article was to investigate the drying kinetics, effective moisture diffusivity, and quality of pitaya in the heat pump drying process. The experiment was conducted at a drying temperature of 50–70°C, slice thickness of 8–10 mm, and a relative humidity of 10–30%. The results showed that the heat pump drying of pitaya was a deceleration process. The drying temperature has the greatest influence on the drying rate. The drying time decreased by 28.57% with the drying temperature increased from 50 to 70°C, while that increased the least by 12% with the slice thickness dropped from 10 to 8 mm. Six drying models were analyzed comparatively based on experimental data, and calculations indicated that the Avhad and Marchetti model could better describe the moisture migration law during the heat pump drying process of pitaya. The optimal drying kinetics model was established to predict the change of moisture content under different drying conditions, and the average error of the model compared with the experimental values was 5.56%. In addition, the effective moisture diffusivity of pitaya ranged from 6.4167 × 10 −10 to 9.8156 × 10 −10  m 2 /s, and the drying temperature had a remarkable influence on the effective moisture diffusivity while the slice thickness had the least. According to the Arrhenius equation, the drying activation energy of pitaya under the experimental conditions was 19.628 kJ/mol. Moreover, the effect of drying temperature on browning degree and surface microstructure was also analyzed. The conclusions of this article provide theoretical support for the analysis of water migration laws and the optimization of the pitaya heat pump drying process.

Because the traditional pulse laser high-precision ranging method has the problems of low ranging accuracy and long ranging time, a pulse laser high-precision ranging algorithm under low signal-to-noise ratio is proposed. Based on the analysis of the basic principle of pulse laser ranging, the pulse laser signal under low signal-to-noise ratio is obtained by modeling the pulse laser echo analog signal waveform. The wavelet denoising method of improved threshold function is used to denoise the pulse laser signal under low signal-to-noise ratio. According to the processing results, the pulse laser high-precision ranging is carried out through sinusoidal amplitude time conversion. The simulation results show that the proposed algorithm has high precision and short ranging time.

The traditional measurement methods of luminescent materials have some problems, such as low accuracy and large amount of calculation. Therefore, a new measurement method is proposed in this article. Taking molecular capture as the core, the molecular force field is established. According to the first law of hohber_Kong’s molecules captures molecular dynamics, it extracts dynamic simulation data information and takes this as the input to establish the Markov data analysis model. The molecular dynamics data were input, and the multi-index method was used to describe the characteristics of metal complex luminescent materials. According to the external shape of the material and the tightness of molecular blocks, the dynamic observation index of the current complex can be obtained to determine the characteristics of luminescent materials. The experimental data show that the method in this article has higher accuracy, lower amount of calculation and good overall error adjustment effect. It can effectively determine the characteristics of complex luminescent materials.

To improve the accuracy of interferometric synthetic aperture radar (InSAR) topographic mapping, an error source analysis method of InSAR topographic mapping based on satellite interferometry is proposed. According to the basic principle of InSAR altimetry, the preconditions of SAR satellite interferometry are quantitatively analyzed, and the phase error experiment is carried out. The error sources of formation satellite InSAR system are studied. Finally, the error sources affecting the formation satellite InSAR system are systematically analyzed. The experimental results show that this method has good analytical performance, quantitatively evaluates the propagation law of each error, and provides a basic reference for practical application.