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Background: COVID-19 has become a global concern as it has ended the lives of lakhs of people. The study done by. Lin proposed the results of an analysis of a theoretical computational model of epidemiology taking into account the crucial components such as response of an individual behavior, measures taken by government, rapid transmission and emigration of fever virus to a huge extent of human population. Simple model framework has been used by them to examine the requirements of essential elements.Problem: We claim the perfect validation of the assumptions stated for the purpose of modeling and its analysis, however, the analytical solution of the presented model is not discussed. And thus have a poor potential to make computational estimates.Methodology adopted: We have tried to present and validate the mathematical/analytic solution of the developed model, considering their assumptions.Conclusion: We have reached to the outcome that the work presented by Q. Lin should be demonstrated adequately with a cautionary advice of not to consider the results and analysis of such numerical models.The current study proposed the results of an analysis of a theoretical computational model of epidemiology taking into account the crucial components such as response of an individual behavior, measures taken by government, rapid transmission and emigration of fever virus to a huge extent of human population. Simple model framework has been used by them to examine the requirements of essential elements. We claim the perfect validation of the assumptions stated for the purpose of modeling and its analysis, however, the analytical solution of the presented model is not discussed. The decision point of this work is to adequately demonstrate along with the cautionary advice of not to use the outcomes and analysis of such numerical models. [ABSTRACT FROM AUTHOR]

In this paper we study the preservation of Lyapunov functions in the numerical integration of ordinary differential equations. By means of a continuous extension and a projection technique we extend the technique proposed by Grimm and Quispel (BIT 45, 2005), so that it can be applied to other families Runge—Kutta methods such as the well known Dormand and Prince 5(4) pair. [ABSTRACT FROM AUTHOR]

In the paper considers a discrete model of SIRD, constructed on the basis of discrete Lotka-Volterra dynamical systems operating in a three-dimensional simplex with a degenerate skew-symmetric matrix. The sets of ignition and the end of the epidemic have been found, and the sets where the population is dying out have been found. The paper also provides a numerical analysis of the proposed model. [ABSTRACT FROM AUTHOR]

In this paper an EPQ model is studied for deteriorating items with non linear price and stock dependent demand under the effect of inflation. Most of the inventory model considers holding cost assumed constant but in real situation it depends on time. Therefore holding cost assumed as a function of time. Shortages are taken partially backlogged type with fixed backlogging rate. The main objective of this proposed paper is to obtain the optimal solution. The numerical analysis has been also done to verify the initiated paper. Finally, a sensitivity analysis is also made for different parameters to obtain some useful observations. [ABSTRACT FROM AUTHOR]

Information about the third symposium on Recent Trends in the Numerical Solution of Differential Equations is presented. Topics include numerical methods for eigenvalue problems and analysis of boundedness of general linear methods. In addition, the event highlighted various studies including the use of the well-known technique of defect correction and a new practical strategy to detect stiffness based on explicit Runge-Kutta schemes.

The present paper analyzes failure observed in polymer rods collided with a steel anvil under the Taylor cylinder impact experiments. The experimental and numerical analysis demonstrates that association of the failure patterns with the loading mode depends on the rod material. Two materials are considered in the paper, specifically, polymethylmethacrylate (PMMA) and polycarbonate (PC). Damage in PMMA rods at the Taylor tests is shown to be dominated by the shear load resulting in plastic deformation. In contrast, the major mechanism of damage in PC rods is governed by omni-directional (pressure) mode of load. Analysis of the damage in sections of the rods associated with the glass transition is also addressed in the present theoretical study. Failure in these polymers follows the traditional fracture wave mechanism for brittle glass-type materials due to load in the corresponding mode. Numerical analysis employs a two-phase model with improved inter-phase thermal balance accounting for the inter-phase mass, momentum, and heat exchanges during the glass phase transition, while damage being accumulated in time. The simulation results demonstrate a good correlation with the experimental results. [ABSTRACT FROM AUTHOR]

This paper deals with the problem of load-bearing capacity and deformability of wood-steel hybrid systems, depending on the selected system constellation, and the possibility of increasing system efficiency and in real conditions by applying pre-stress, in accordance with modern principles of structural conceptual design. The subject of the research is the behaviour of pre-stressed glued laminated beams with external polygonal ropes, different researched constellations, i.e. strut type hybrid systems, in real conditions. The paper is practically divided into three methodological units: theoretical and numerical analysis, and examples of practical applications, and on the theoretical basis of urban transformations of historical units. Theoretical assumptions, as well as the current and own approach to the analysis of parameters, set the theoretical basis for the analysis of these systems and the possibility of applying numerical methods in practice. Parametric analysis of the hybrid system obtained practical expressions and diagrams for use in practice, needed to determine suitable constellations of strut type hybrid system by different geometric characteristics and pre-stressed hybrid system, and for different percentages of wooden girder moisture. In order to compare these systems, the same assumptions were used for the calculation, namely: plane behaviour of the system, and to determine the effective pre-stressing, the condition of annulment of vertical deflection in characteristic cross-sections was used, i.e. achieving the effect of vertical immobility of the struts, from which the measure of pre-stressing of the deformable system was obtained. A hybrid system with a wooden girder, which has bending stiffness, is often used in construction, and the main disadvantage of such a system is the expressed deformability in real operating conditions. The basic thesis of this paper is that by external pre-stressing of glued laminated girder achieves less deformability and increases bearing capacity, while saving base material in real conditions, and is confirmed by our own parametric analysis and laboratory testing of pre-stressed hybrid systems of different constellations. The attached parametric analysis diagrams provide a sufficiently accurate orientation for finding the correct constellations of wood-steel hybrid systems and the possibility of estimating the efficiency of hybrids in real conditions, as well as the necessary pre-stressing applications. The derived expressions of the approximate procedure and the expressions for finding the effective pre-stressing force, assuming the linear behaviour of the system, give sufficiently accurate results for the design of pre-stressed hybrid systems in practice. Also, with this or similar methodology it is possible to qualitatively investigate hybrid systems with different combinations of materials. The presented conceptual solutions for the integration of hybrid systems and modern materials in specific localities represent a contribution to the development of a methodological approach to the transformation of historical urban units. [ABSTRACT FROM AUTHOR]

In this paper, buckling analysis of composite stiffened panel with different shapes stiffener under uniaxial compressive load was carried out. Buckling behavior of straight stiffened panel on different shape of stringers were studied and compared. Stiffeners are providing the stiffness to the stiffened panel. In this paper several types of shapes like Z- shape, L-shape, Hat shape, I-shape, C-shape, J-shape and T- shape were taken. Numerical analysis done by non- linear software (ABAQUS 6.14-1). Main motive of this paper understands the shape of stringers and influences of the shapes in buckling strength. Influences of stiffener with various cross section areas of stiffened panel were deciding the buckling strength of the panel. Once buckling strength was improved, relatively high stiffness of assembly is also improving. Closed sections and more fasteners providing high buckling loads. [ABSTRACT FROM AUTHOR]

The presence of lead material in lead halide perovskite absorber is always remains a major obstacle due to its toxic nature. The emergence of tin halide perovskite absorber will overcome this toxicity issue and due to its extraordinary properties such as direct band gap and compatible visible spectrum of solar cells attracts a wide attention to researchers to focus on the development of lead free perovskite solar cells. This paper comprises of the device simulation of lead-free perovskite material. In addition, effect of various hole transport layers, and the effect of absorber band gap have been studied. It has been observed from the results that along with the proper band alignment of HTM layer with perovskite layer, the mobility of HTM layer plays an important role to achieve better device performance. Furthermore, it has been concluded that Cu2O layer as a hole transport material exhibits better device performance as compare to the other HTM layer used in this paper. [ABSTRACT FROM AUTHOR]

The development of modern society is conditioned by the accelerated pace of development of technological awareness. Our urban environment is increasingly exposed to radical transformations, leaving no room for perception and adoption of the new, almost excluding the feeling of belonging to the transformed environment. Such changes, caused by the expansion of construction activity, often violate the ambient and original values, in the transformed environments of "captured" cultural and historical heritage Objects of cultural and historical heritage possess historical, artistic and aesthetic value, readability in all their historical changes and the symbolic value of the tradition of the society to which they belong. Preservation of spiritual, formal and traditional originality, with all the technical characteristics they carry with them, emphasizing the uniqueness and representativeness of heritage in a modern environment, is an imperative in preserving one's own identity. The constructive characteristics of the historical heritage building were dictated by the degree of technical knowledge, experience and intuitiveness of the builders of that time. The specificity of structural systems and construction techniques have a direct impact on the architectural character of buildings, and thus the approach to structural repair, considering the problem exclusively from the point of view of structure and application of modern methods of numerical analysis and technology, can be a cause of disavowal of these buildings.Thus, questions arise: How sovereign are new knowledge and methods over the old, or is it necessary to awaken the intuitiveness of today's builders? How to achieve compatibility of old and new, where necessary? In this paper, the case study of a specific sample of the cultural and historical heritage of Despic House will provide answers to the questions asked. Despic House, where the first theatre in Sarajevo was founded, is one of the few material evidences of life in the city at the turning point of the Ottoman and Austro-Hungarian periods. Atypical in relation to the local way of building, it is a unique example of a combination of the traditional heritage of the Ottoman period and the " breakthrough of European creativity into the culture of this area". This paper presents a complex research process of establishing the genesis of the Despic House, as well as the consequences of the influence of urban transformations in the spatial framework at the level of the architectural object and the level of the urban-architectural ensemble. On the example of established and implemented measures of structural repair of this building, the importance of a multidisciplinary approach to detailed research and conservation-restoration works for cultural and historical heritage buildings will be confirmed, taking into account its original values. [ABSTRACT FROM AUTHOR]

Information about the Recent Trends in the Numerical Solution of Differential Equations second symposium is presented. Topics discussed include the numerical method of Hamiltonian problems, new definition of stiffness with applications and numerical methods for variational inequalities. The meeting featured several mathematics experts, including L. Aceto, L. Brugnano and R. Lamour.

The impact of physical loads in the automotive assembly line has been investigated in the automotive and manufacturing industries. The purpose of this paper is to systematically examine the impact of human factors on worker quality performance in designing and managing manufacturing operations. Tiredness and efficiency deficits have a good relationship. Thus, the display of fatigue graphs, and S-N curve about overloading, heavy manufacturing work in industry depicts stress and fatigue are inversely proportional to the number of cycles. Also, the authors determine the fatigue limit numerically by calculating the r-ratio or amplitude ratio. Data was collected from the rail coach factory, Kapurthala using a particular database system. [ABSTRACT FROM AUTHOR]

Fourteen airfoils were selected in this research paper to build and optimize a small horizontal axis wind turbine for a low wind speed. By using Q-blade software and CFD simulations for a 0.5 m rotor radius and the tip speed ratio ranged from 3 to 10. In this paper selected airfoil such as E205, E214, E216, NACA2412, NACA4418, SG6040, SG6041, SG6042, SG6043, S1221, S2091, S7012, SD7034 were investigated. As the most suitable geometries, Airfoil E216 and SG6043 cast out by checking numerical simulations to gain more power at low Reynolds number. In this study comparing the drag coefficient, lift coefficient and lift to drag ratio with respect to angle of attack, the airfoil has been revised. A parametric optimization of the blade geometry and develop the new airfoil for small wind turbine rotor. The E216 airfoil is found to be better performance with below solidity of8.25%, while the NACA 2412 produces stronger solidityof 21.6% due to wake effects produced behind the rotor. A wind tunnel test, Q-Blade simulation and CFD analysis were performed on the design and optimized for the proposed small horizontal wind turbine rotor axis in order to apply low wind speed area. [ABSTRACT FROM AUTHOR]

Functionally Graded Materials (FGMs) is a new composite material with gradients of material composition. The FGMs introduce by scientists from Sendai, Japan. The properties of FGMs used in this paper are metal and ceramic. Metal is a material that is resistant to structural flexibility, while ceramic is a material that is resistant to high temperatures. This paper presents the free vibration of FGMs beams using the Mixed Quadratic Beam (MQB) element. This paper begins with the formulation of the MQB element, then followed by numerical analysis of free vibration on FGMs beams problems. Free vibration analysis of FGMs beams is done by solving a simple supported (SS) beam with L/h=5. The results are compared to the reference solution. From the analysis, it can be concluded that the MQB element shows promising results for beams with a large number of elements. [ABSTRACT FROM AUTHOR]

Today, the study of the distribution of emissions in the atmosphere is quite an urgent task, because harmful substances, getting into the surrounding atmosphere, cause harm to the health of people, flora and fauna. In this paper, the results of simulation of the distribution of emissions from the Ekibastuz TPP (GRES 1) are presented. For simulations the model of turbulence was chosen. Simulations were performed by using the ANSYS 16.0 software package. Previously, the model and numerical algorithm were tested using a model problem and the results were compared with the experimental data. [ABSTRACT FROM AUTHOR]

The Rim-driven Thruster (RDT) is a new type of marine electric thruster proposed in recent years. In this paper, the author proposed a new type of permanent magnet synchronous rim thrust motor (RTM). The motor uses a Halbach array permanent magnet rotor, which can improve the torque density of the propulsion motor by utilizing the unilateral magnetic field of the Halbach array.In this paper, the electromagnetic properties of the motor were measured and compared with that of the ordinary magnetic pole motor through numerical analysis. The results show that at the same power, the new motor can significantly reduce the thickness of the rotor's permanent magnet and yoke core, and has obvious advantages in power density, moment of inertia, dynamic performance, and cost. [ABSTRACT FROM AUTHOR]

This paper deals with the numerical investigation of ellipticity of the boundary value problem for isothermal finite strain elasto-plasticity. Ellipticity can be lost when softening occurs. A discontinuity surface then appears in the considered material body and this is associated with the ill-posedness of the boundary value problem. In the paper the condition for ellipticity loss is derived using the deformation gradient and the first Piola-Kirchhoff stress tensor. Next, the obtained condition is implemented and numerically tested within symbolic-numerical tools AceGen and AceFEM using the benchmark of an elongated rectangular plate with imperfection in plane stress and plane strain conditions. [ABSTRACT FROM AUTHOR]

In the paper a kind of meshless discretization technique, called the Kansa method, is investigated in the context of problems with multiple boundary conditions. This numerical method uses interpolant composed of radial basis functions as well as collocation technique to discretize differential equations. To overcome the problem that appears for equations with multiple boundary conditions, where more equations should be associated with a boundary node than degrees of freedom that exist at this node, an extension of the method is proposed. The key idea lies in the modification of the interpolant with the use of Hermite formulation. The details of the approach are shown in the paper. Moreover, the special attention is paid to estimate respective value of the shape parameter included in radial functions to ensure stability of the solution process and high accuracy. To illustrate usefulness, accuracy and convergence of the method, it is employed to solve a test problem of the bending Kirchhoff plate. [ABSTRACT FROM AUTHOR]

The traditional Canny algorithm has poor self-adaptability threshold, and it is more sensitive to noise. In order to overcome these drawbacks, this paper proposed a new edge detection method based on Canny algorithm. Firstly, the media filtering and filtering based on the method of Euclidean distance are adopted to process it; secondly using the Freichen algorithm to calculate gradient amplitude; finally, using the Otsu algorithm to calculate partial gradient amplitude operation to get images of thresholds value, then find the average of all thresholds that had been calculated, half of the average is high threshold value, and the half of the high threshold value is low threshold value. Experiment results show that this new method can effectively suppress noise disturbance, keep the edge information, and also improve the edge detection accuracy. [ABSTRACT FROM AUTHOR]

Islamic banking in Malaysia offers variety of products based on Islamic principles. One of the concepts is a diminishing musyarakah. The concept of diminishing musyarakah helps Muslims to avoid transaction which are based on riba. The diminishing musyarakah can be defined as an agreement between capital provider and entrepreneurs that enable entrepreneurs to buy equity in instalments where profits and losses are shared based on agreed ratio. The objective of this paper is to determine the internal rate of return (IRR) for a diminishing musyarakah model by applying a numerical method. There are several numerical methods in calculating the IRR such as by using an interpolation method and a trial and error method by using Microsoft Office Excel. In this paper we use a bisection method and secant method as an alternative way in calculating the IRR. It was found that the diminishing musyarakah model can be adapted in managing the performance of joint venture investments. Therefore, this paper will encourage more companies to use the concept of joint venture in managing their investments performance. [ABSTRACT FROM AUTHOR]

The general formula proposed by Landes and Begeley [1], which has been modified for years, among which more or less complicated approaches can be distinguished for determining the J-integral in laboratory conditions. One of them is the ASTM standard [2], according to which the energy required to calculate the J-integral should be decomposed into elastic and plastic parts, and thus the factor η depending on the shape of the specimen used in laboratory tests. Some approaches, e.g. the Polish standard [3], indicate that the J-integral should be calculated without decomposing into elastic and plastic parts. The normative documents mentioned do not usually mention the dependence of the η factor on the geometrical dimensions of the specimen (except for the shape of the specimen) or the dependence on the material characteristics. As shown in [4-7], the value of the coefficient η depends on the crack length and the material characteristics, however, the influence of material constants is usually discussed in a strictly defined range. It should be noted that papers [4-7] are based on the decomposition of the coefficient η value into elastic and plastic parts. The hybrid method presented in [8] for assessing selected parameters of fracture mechanics, referring to EPRI procedures [9], allows to evaluate them without the need for tedious numerical calculations, however, unlike EPRI procedures, it does not introduce the need to decompose these parameters into elastic and plastic components. In view of this fact, in this study it was decided to assess on the basis of numerical calculations carried out for the dominance of plane strain, the effect of crack length and material constants (expressed in yield strength and strain hardening exponent in R-O law) on the value of the coefficient η which is required to estimate the value of the J-integral in accordance with by Landes and Begeley [1]. The discussion presented in [10] was the inspiration to undertake this topic. In this paper, based on a comprehensive numerical analysis of SEN(B) specimens dominated by a plane strain state, for four different crack lengths and sixteen hypothetical elastic-plastic materials (characterized by different yield strength and different level of stain hardening exponent), the values of the J-integral were estimated, the impact of the crack length and material constants on the value of J-integral was assessed, an analysis of the P=f(u) curves and discussion on the effect of crack length and material constants on the value of the factor η were presented. Using the approach given in [4-7], simplification was made in the analysis and the value of the coefficient η was determined for each analysed specimen. The analysis showed a strong dependence of the coefficient η on the crack length and the strain hardening exponent n. It turned out that the coefficient η does not depend on the yield strength of the specimen material. The results were summarized in tabular form and approximated using the Table Curve 3D program. The measurable effect of the paper is a summary of numerical results – values of the coefficient η for 64 SEN(B) specimens and a new form of the function η=f(a/W, n) which was proposed, and which allowing to take into account in the process of determining the J-integral by the factor η the geometry of the specimen (relative crack length a/W) and material characteristics (n – strain hardening exponent in R-O law). [ABSTRACT FROM AUTHOR]

An unmanned aerial vehicle (UAV) that is able to take-off and land on a medium sized ship, have greater endurance and range as compared to the previous iteration, and the ability to achieve all three flight modes - vertical, transition and horizontal flight modes is to be designed, built and tested. In this paper a comprehensive review is given on various VTOL planform configuration and a tilt-rotor configuration is selected for Minerva 2.0 for its high stability and increased efficiency. This paper covers the selection analysis of different vertical take-off and landing (VTOL) airframe as well as mechanical and electronic hardware design with the intention of increasing flight efficiency for surveillance purposes on wide sea area. This paper presents Minerva 2.0, a novel aerial platform with VTOL capabilities. Numerical and analytical analysis results are discussed. The previous iteration, Minerva 1.0 was built and tested as a QuadPlane configuration and an increased efficiency of 25 to 58.7% is achieved in this paper. [ABSTRACT FROM AUTHOR]

The article discusses various reports published within the issue, including one on parallel approach in solving differential equations and another on high-order block methods.

This paper presents the numerical method applied to predict the performance and wave wash of the river craft. In recent years fast ferries have been introduced on many ferry routes all over the world. Mainly when operating in shallow waters and near the coast, the waves generated by these crafts give escalate to clash with recreational use of beaches and coastal waters. The performance of HSC vehicle in these areas and the potential coastal erosion caused by a changed wave impact has been a subject of concern. In this paper, a finite volume method (FVM) and RANS approach was applied to investigate the wave wash, resistance, trim, and pressure acted on the craft. Actually a dynamic mesh with two degrees of freedom was used and the results were compared with a markedly proper experimental results and the competency of applied method was proved. [ABSTRACT FROM AUTHOR]

This paper presents a study of rarefaction effect on hypersonic flow over a sharp leading edge. Both continuum approach and kinetic method: a widely spread commercial Computational Fluid Dynamics-Navior-Stokes-Fourier (CFD-NSF) software - Fluent together with a direct simulation Monte Carlo (DSMC) code developed by the authors are employed for simulation of transition regime with Knudsen number ranging from 0.005 to 0.2. It is found that Fluent can predict the wall fluxes in the case of hypersonic argon flow over the sharp leading edge for the lowest Kn case (Kn = 0.005) in current paper while for other cases it also has a good agreement with DSMC except at the location near the sharp leading edge. Among all of the wall fluxes, it is found that coefficient of pressure is the most sensitive to rarefaction while heat transfer is the least one. A parameter based on translational nonequilibrium and a cut-off value of 0.34 is proposed for continuum breakdown in this paper. The structure of entropy and velocity profile in boundary layer is analyzed. Also, it is found that the ratio of heat transfer coefficient to skin friction coefficient remains uniform along the surface for the four cases in this paper. [ABSTRACT FROM AUTHOR]

The main purpose of the suspension system is to absorb the vibrations from wheels. To compromise between the two conflicting criteria i.e. road holding and ride comfort, passive suspension system is most suitable. The passenger discomfort is caused due to unwanted vibrations which are transmitted through unsprung mass. The numerical analysis using Simulink MATLAB software is used to determine Ride comfort of two suspension systems based on quarter car model. The experimental setup is developed and vibration analysis is performed using multichannel FFT analyser. The mathematical analysis result of the two different models of the suspensions is compared with experimental analysis. The aim of paper is to investigate effect of sprung mass on ride comfort at constant speed with input 0.1m peak stroke which generated a waveform resembling to half sine wave. The mathematical model is developed and analysed in Simulink MATLAB software. [ABSTRACT FROM AUTHOR]

In our models we assumed that all objects are of good quality. This is possible only under very impractical conditions but actually this is not possible. This paper deals with a two level supply chain Management for fault items. To certify orders, the producer offers some facilities to the retailer such as trade credit for some part of the order, free shipping on the basis of advance payment amount. Enlargement cost is taken as a function of time to keep the fulfillment of the manufacturing system. To find optimum profit we use fuzzy Monsoon demand without shortage. Screening process is also considered to identify whether the formed items are perfect or imperfect. In this paper we derive some useful algorithms to find the optimal solution. Moreover, sensitivity analysis and numerical analysis are made to justify the optimum solution. [ABSTRACT FROM AUTHOR]

The basic function of the gas turbine blades is to rotate the shaft connected to the generator motor. In electricity generation station, because the materials used in manufacturing must resist harsh working conditions, gas turbine blades are subject to high vibration, pressure and temperature. In this paper, the maximum pressure and deformation are caused by the effect of centrifugal force on the gas turbine blades. And to determine the natural frequencies of vibration, which are caused by the rotation speed about 3000 r.p.m under high-temperature conditions. The finite element method (FEM) was used to determine the natural frequency of turbine blade material (GTD-111) applied in the South Baghdad Power Station in Iraq, Baghdad. This paper deals with the structural analysis of gas turbine blades. Analysis was performed to find out the mechanical stresses and radial elongation to which the gas turbine rotor blade is subjected. A solid turbine blade model is constructed using the SOLIDWORKS2018 software. The turbine blade is analyzed for its structural performance due to the loading conditions using ANSYS 19 software to study the stress variation on the GTD-111 alloy gas turbine blades. The results shows that under static load and the stress and strain on the blade, the amplitude of the blade vibration will change at the higher frequencies of 581.42 Hz and 935.84 Hz because the root of the blade is placed on the disk-like cantilever (girder fixed at only one end). [ABSTRACT FROM AUTHOR]

Theoretical analysis to predict the crack propagation of Al 2024 is required and validated by experiment. This theoretical analysis was developed through a mathematical model that is based on the development of the Paris equation. The Paris equation is used to analyze crack propagation against a constant amplitude load. In this paper, a mathematical model based on the Paris equation is developed for the load spectrum, where the effective results are obtained at stage 2 when conditions are stable. The results of the development of this mathematical model are quite promising to be used as a reference for further experiments with the same material [ABSTRACT FROM AUTHOR]

This paper deals with a slat chain conveyor for the transport of rock materials in very severe abrasive conditions. An actual case from practice is discussed and analysed. To clarify the fatigue damage of the chain link material, the finite element method (FEM) is applied. For the experimentally recorded cycle of chain loading, numerical analysis has been performed and data for the damage of the link material are presented. Fatigue analysis is performed by ANSYS nCode DesignLife under different loading cases. FEM results show, that the fatigue crack of the link starts from region with high values of the stresses, established by experiment. [ABSTRACT FROM AUTHOR]

A finite element analysis on crash box of an automotive bumper system is presented in the paper to investigate the energy absorption of the component with and without foam-filled steel sheet metal tubes of different thicknesses for crashing or low-velocity impact analysis. The energy absorption capacity of the crash box for crashing is evaluated for different design changes of the foams-tube structure and compared the results without foam. By changing the different foam materials, various designs are proposed and simulated for maximum energy absorption. Altair Hyperworks is used for preprocessing and post-processing and Radios solver is used to run the analysis. A reasonable agreement is obtained in the results of the analytical and numerical methods. The results indicate that the energy absorption of a foam-filled crash box structure is superior to the crash box without foam. [ABSTRACT FROM AUTHOR]

The main idea of this paper is to give a profound investigation of the aerodynamic properties of a wing for Cessna 172S. The numerical analysis of total drag is developed by using various methods from different references, the 2D and 3D lift curve parameters of the wing Cessna 172S are generated according to the analysis method depending on empirical equations. The first stage of modelling Cessna 172S is evaluated according to the airfoil of Cessna NACA 2412, whereas the second stage of modelling is estimated by using wing planform properties. The maximum lift coefficient, lift curve slope, zero angle of attack, lift at zero angle of attack, and stall angle of attack are calculated by using different empirical equations. [ABSTRACT FROM AUTHOR]

Texture masking has been used as a significant factor in creating perceptual maps that simulates human vision system in observing noise in digital images. In this paper, the possibility of creating texture masks using first and second derivatives is investigated and tested. Results shows that after applying the derivatives, areas of higher texture were highlighted and recognized, which will lead to simple implementation of texture masks using numerical analysis. [ABSTRACT FROM AUTHOR]

The following paper aims to provide a detailed analysis of the effect of different cutting speeds in the face milling of AISI 1045 steel using coated tool. Simulations would aid in solving problems associated with experiments, leading to reduced costs and risks. DEFORM 3D is a commercially used simulation software capable of implementing machining simulations using the theory of finite element modelling. A conventional DEFORM 3D milling model has been prepared for the analysis of cutting forces and chip formation and the simulation has been carried out for two conditions. The temperature and force parameters were analyzed after carrying out the experiment and simulation under the influence of different machining and environmental conditions. The results of the simulation revealed that the predicted values of FEA possess good accuracy. [ABSTRACT FROM AUTHOR]

Steel coupling beam is a substantial member in hybrid coupled walls system that greatly enhance the strength and the energy dissipation capacity of the system compared to coupled walls linked by convention reinforced coupling beams and diagonally reinforced coupling beams. To enhance these characteristics even more, a corrugated web may be used instead of the traditional flat web. This paper presents a numerical analysis using finite elements software (ABAQUS) to investigate the nonlinear behavior of both types of steel coupling beams (with flat web and with corrugated web). The effect of initial imperfection on the nonlinear behavior of steel coupling beams was taken into account. The results were compared with the available experimental data of steel coupling beams with the flat web. Good agreement was noticed between the experimental and the numerical results. Among the conclusions drawn in this study is that using a corrugated web as an alternative to a flat web may increase both the strength and the energy dissipation of the steel coupling beams. [ABSTRACT FROM AUTHOR]

This paper deals with method of B-spline solution for a system of boundary value problems. The differential equations are useful in various fields of science and engineering. Some interesting real life problems involve more than one unknown function. These result in system of simultaneous differential equations. Such systems have been applied to many problems in mathematics, physics, engineering etc. In present paper, B-spline and B-spline with free parameter methods for the solution of a linear system of second-order boundary value problems are presented. The methods utilize the values of cubic B-spline and its derivatives at nodal points together with the equations of the given system and boundary conditions, ensuing into the linear matrix equation. [ABSTRACT FROM AUTHOR]

The paper is devoted to investigation of mechanical response of an electro-viscoelastic structure (a structure with piezoelectric element attached to its surface) in case when electric voltage with prescribed parameters is applied to electrodes of piezoelectric element. A cantilever plate was considered as such a structure. An amplitude of displacements of the free end of the plate at resonant modes is considered as a mechanical response in case when forced steady-state vibrations occurring under kinematic or force loading are considered. Mechanical response of the structure is determined numerically using the ANSYS software package. Viscoelastic properties of a material of the plate are taken into account using the model with complex dynamic moduli. Within the frameworks of this paper relations between mechanical response of the structure and magnitude and polarity of electric voltage applied to electrodes of a piezoelectric element was obtained with respect to a type of excitation of vibrations. [ABSTRACT FROM AUTHOR]

Contact deformation behavior of elements of spherical support structures of different geometrical configuration was considered: with anti-friction layer located in the lower steel slab and with anti-friction layer applied to the spherical segment. Within the framework of the paper, numerical analysis of the effect of the anti-friction polymeric layer face angle of spherical support structures on the deformation behavior of the work as a whole and changes in the parameters of friction contact zones, in particular, was performed. On average, the maximum contact pressure level of the spherical support structure model with a layer located in the lower slab is 8.5 % lower, and the maximum level of normal-to-surface movements is more than 28% lower than that of the second model considered. The opening of the contact near the edge of the anti-friction layer approximately by 1% of the surface is observed in all considered variants of spherical support structures. Areas of contact detachment of the interface surfaces in the model with an anti-friction layer in the lower slab are observed at a face angle of 20 degrees or more. For the model with an anti-friction layer applied to the spherical segment, an opposite situation is observed, namely, the contact opening occurs at the face angles from 0 to 10 degrees. In general, with an increase in the face angle from 0 to 30 degrees, there is an increase in deformation parameters of the contact node and parameters of contact zones. [ABSTRACT FROM AUTHOR]

This paper is devoted to numerical analysis of plaster detachment and numerical experiments for determination of the appropriate material parameters. Interaction between the plaster and masonry is described with the help of interface finite elements which are equipped with traction-displacement relationship. Laboratory tests were introduced in order to determine the shear capacity of the masonry-plaster connection. Unfortunately, variability of measured behaviour was very large and additional tests are needed. [ABSTRACT FROM AUTHOR]

A simple finite volume scheme is proposed to solve the shallow water equations on staggered grids. We consider the one-dimensional nonlinear shallow water equations in their conservative forms. We limit our research results in this paper for subcritical flows. Numerical tests show that the scheme solves subcritical flow problems quite accurately. In addition, the computation is very cheap due to the simplicity of the scheme. [ABSTRACT FROM AUTHOR]

One of the most common problems with quasi-Newton methods is how to select the suitable quasi-Newton equation while operating the algorithm. In this paper, a new modification Quasi-Newton equation is proposed based on recent quasi-Newton equation of the Biglari et.al. method. Theoretical analyses and numerical computations using standard functions, as well as comparison with Broyden-Fletcher-Goldfarb-Shanno (BFGS) show that the proposed new type is globally convergent and computationally efficient. [ABSTRACT FROM AUTHOR]

In this paper, we study the global solvability and unsolvability of one nonlinear system of non-Newtonian polytropic filtration with a nonlocal boundary condition in the case of slow diffusion. We are constructed various self-similar solutions to the nonlinear filtration problem in the slow diffusion case. The conditions for the global existence of a solution in time and unsolvability of the solution of the nonlinear filtration problem based on the method of standard equations, self-similar analysis and comparison principles are found. Establish the critical global existence exponent and critical Fujita exponent, which play an important role in the study of qualitative properties of nonlinear models of nonlinear reaction-diffusion, thermal conductivity, filtration, and other physical, chemical, and biological processes. In the case of the global solvability the main term of the asymptotics of solutions obtain. For the numerical investigation of the nonlinear filtration problem is provided a method of selecting suitable initial approximation for the iterative process. Using asymptotic formulas as the initial approximation for the iterative process, numerical calculations and analysis of the results are performed. [ABSTRACT FROM AUTHOR]

The main purpose of this paper is examination of an application of modern parallel computing technique OpenMP to speed up the calculation in the numerical solution of parametric integral equations systems (PIES). The authors noticed, that solving more complex boundary problems by PIES sometimes requires large computing time. This paper presents the use of OpenMP and fast C++ linear algebra library Armadillo for boundary value problems modelled by 3D Laplace's equation and solved using PIES. The testing example shows that the use of mentioned technologies significantly increases speed of calculations in PIES. [ABSTRACT FROM AUTHOR]

It has been reported that Internet Protocol (IP) packet traffic exhibits self-similarity or long range dependence (LRD) and causes the degradation of switch performance. Therefore, it is crucial for an appropriate buffer design of a switch. In this paper, we investigate delay behavior of the switch under self-similar variable length packet traffic by modeling it as MMPP/M/1/K queueing system wherein MMPP (Markov-Modulated Poisson Process) is fitted by equating the variance of MMPP and that of self-similar traffic. MMPP model is already validated one to emulate the self-similar characteristics. Voids that will occur because of variability in packet length is considered. We investigate mean delay against system parameters, traffic parameters and fitting parameters. Numerical results show that analysis presented in this paper is useful in dimensioning the switch. [ABSTRACT FROM AUTHOR]

Titanium alloy based details due to their mechanical properties continue to be in extensive use in various structures (mainly aerospace, automotive and petro-chemical industrial applications). In this paper comparative study of various types of eddy current NDT transducers for testing titanium elements was done. Probes of absolute, differential and array configurations were constructed and analyzed. Two and three dimensional numerical analysis (FEM) were done in order to find the best type and configuration of the proposed transducers. [ABSTRACT FROM AUTHOR]

In this paper we revisit the known problem of the explosion suppression by a cloud of inert and solid particles. This issue has been so far investigated experimentally where the most important task has been to find the proper suppressant, estimate its quantity, as well as design the quenching device. Also some attention has been paid to numerical investigation where by use of computer simulation the same questions have been asked. In this paper we also focus on the numerical study, where the first moment of the suppressing process is analysed: the exact behaviour of the particle cloud as it reacts with the gas. A mathematical model is presented that bases on the Eulerian-Lagrangian approach for the description of the both phases: solid and gas. Finally some results are shown: both snapshots of particle location as well statistics. [ABSTRACT FROM AUTHOR]

In this paper we propose a numerical method for solving regime-switching problem with power utility function. The model is a system of parabolic equations with non-linear gradient term and weakly coupled by exponential non-linearity. First, we approximate the gradient term, involving an auxiliary non-linear function, then we construct implicit-explicit finite difference discretization. We prove discrete comparison principle and on this base we establish minimum principle, i.e. we prove that the numerical solution has the same lower bound as the exact solution. Convergence result in maximal norm is obtained. Numerical results, confirming the theoretical statements are provided. [ABSTRACT FROM AUTHOR]

This article concerns issue of dynamic response of structures. Practical analysis of dynamic behaviour of structures is one of the current directions of structural mechanics. In practice structures are undergo different types of load pulses and their behavior under such loads need to be investigated more with different examples. A single-storey frame was chosen as a subject of this research, the model is single mass system. Dynamic analysis needs to be conducted using both obvious graphic representation and powerful means for programming and numerical analysis, so the Python language environment was chosen as an analysis tool. Three types of loading pulses are considered: constant with finite rise time, rectangular and two-legged triangular. Different period ratio cases are also calculated for each loading type. The results include comparison of response for different loading cases and varying of ratio between load pulse period and the frame natural period. The comparison shows that the dynamic load factor decrease as the amplitude increases and also structural dynamic response is significantly influenced by the natural period. Finally, this paper, for future works, recommends the extension of the investigation of the dynamic structural response of frames to address the questions related to the influences of other factors in addition to the effects of the natural periods. [ABSTRACT FROM AUTHOR]

In this paper, we consider some aspects of the numerical analysis of the mathematical model of fractional Duffing with a derivative of variable fractional order of the Riemann-Liouville type. Using numerical methods: an explicit finite-difference scheme based on the Grunwald-Letnikov and Adams-Bashford-Moulton approximations (predictor-corrector), the proposed numerical model is found. These methods have been verified with a test case. It is shown that the predictor-corrector method has a faster convergence than the method according to the explicit finite-difference scheme. For these schemes, using Runge's rule, estimates of the computational accuracy were made, which tended to unity with an increase in the number of calculated grid nodes. [ABSTRACT FROM AUTHOR]

This paper presents numerical simulations of the water flow in the case of an emergency at the protective hydraulic engineering constructions. A mathematical model for simulation of flooding flow is based on Navier-Stokes equations coupled with the volume-of-fluid (VOF) method. The 2D computational domain is discretized via the finite volume method (FVM). For turbulence modelling, the k-ϵ model is chosen. The interface between air and liquid is captured by CICSAM (compressive interface capturing scheme for arbitrary meshes) scheme, whereas the semi-implicit method for pressure linked equations (SIMPLE) scheme is applied for the pressure-velocity coupling. A second order upwind discretization scheme is used for the momentum equations. The verification of the present results is produced on a single flooding water body. The results show a good agreement with previous simulations and experiments of different authors. Then the simulation is expanded and analysed for cases with two different types of obstacles. Numerical simulation results are illustrated by figures and tables. [ABSTRACT FROM AUTHOR]

This paper describes one method for a numerical solution of a Fredholm integral equation of the second kind. The kernel function has a special type of singularity called the diagonal one. The main result of this paper is the error estimation of the numerical solution based on the Nystr¨om method with singularity subtraction. The error estimate is compared to numerical examples. The error behavior and computing time of the Nytr¨om method is compared with alternative method. [ABSTRACT FROM AUTHOR]

Simulation of the aircraft assembly process is an important problem arising from the airline industry. To address this problem, a methodology was developed in previous studies, which is based on the contact problem solving. This paper is devoted to further development of numerical methods for simulation of fuselage junction riveting process. The methodology of a contact problem solving was developed to simulate the aircraft assembly process. In the developed algorithm, the initial contact problem is transformed into the problem of quadratic programming with linear constraints. As the installed fasteners restrict relative tangential displacements of assembled parts in the junction area, the relative tangential displacements are negligible in comparison with normal ones. This special feature of the problem justifies implementation of node-to-node contact model that is much simpler than general surface-to-surface model.However, this implementation imposes the restriction that all finite element nodes of parts in the contact area should coincide completely. This restriction creates difficulties during mesh building because it is much easier to build meshes of the parts independently from each other. The main contribution of this paper is introducing the method and extending the existing algorithm for airframe assembly simulation to the case of non-conformal meshes. This article introduces the method and the modernized algorithm for the riveting process with non-conformal meshes. [ABSTRACT FROM AUTHOR]

This paper presents the characteristics of the process of longitudinal rolling of shafts and the geometry of the working section of forming rollers with a secant profile. In addition, the analytical formulae defining the geometry of a roller profile were determined. The experiments were carried out on shafts made of S235JR and C45 structural steels and the MSC.Marc + Mentat program was used for the numerical analysis of the rolling process based on the finite element method. The paper analyses the effect of roller geometry on the changes in value of the widening coefficient and the diameter reduction coefficient for the first forming passage. It was found that the mechanical properties of the shaft material have a slight influence on the widening coefficient. The value of the widening coefficient of the shaft increases with increase in the initial diameter of the shaft. Increasing shaft diameter causes an increase of strain gradient on the cross-section of the shaft. [ABSTRACT FROM AUTHOR]

Pre-impregnated materials (Prepregs) have greatly impacted many industries that require specific advanced composites, such as aerospace structures for UAVs. Prepreg material aids the structure by reducing weight while increasing strength and allowing for reasonably consistent manufacture. One of the most essential features of these materials is the variation in properties as the orientation of the layer changes. This requires the use of advanced techniques for strength analysis, including numerical modelling and material testing. This paper presents an experimental evaluation approach to estimate the mechanical properties of composite shells, including cutting schemes, specimen preparation, and test procedures. In the next stage, this study discusses the use of ABAQUS FEA to replicate the phenomenon of specimen failure modes. The investigated prepreg specimens in this study were created using XC 130 unidirectional easy composite prepreg. Through this research, the failure mode results of testing and numerical analysis showed a good agreement. [ABSTRACT FROM AUTHOR]

In this paper the numerical investigations concerning static response of a different configurations of concrete columns subjected to Euler's load are presented. An original approach of connecting the column and pocket footing via steel cut-off pyramid heads is presented. As shown in other works the main difference between conventional planar ended column and the column ended with cut-off pyramid shape is the axial force redistribution at the connection. In the case of standard connection, the compressive force is transferred onto foundation and consequently from the point of connection that force is distributed outwardly with 45° degrees' incline angle onto the ground. With the presented cut-off pyramid connection, one makes possible to reduce foundation height as a result of transferring on footing and consequently to the ground only a part of the compressive force, whereas remaining amount of force is converted into tensile stress effectively taken over by steel reinforcement. A comparative numerical analysis using SolidWorks FEM based software between standard and proposed solution is performed taking into account columns' critical load and Misses-Hencky stress (MHS) redistribution near the columns' head. On the basis of presented results, both solutions advantages and disadvantages are emphasized. [ABSTRACT FROM AUTHOR]

The paper deals with the determination of the rotational stiffness of a timber semi-rigid joint. The rotational stiffness was calculated on the basis of the currently valid standard, experimental test and numerical model. The connection was made of a standard combination of bolts and dowels, which consisted of 10 pieces of fasteners with a diameter of 8 mm. The elements of the connection consisted of facades and two struts with a cross-section of 100x300 mm. The connection was then statically repeatedly loaded and relieved. The loading took place up to the level of the ultimate limit state and the unloading up to 10% of the maximum value. In order to determine the actual mechanical properties of timber and fasteners, partial tests were performed for the needs of numerical modelling. [ABSTRACT FROM AUTHOR]

Members of open double-symmetrical cross-sections are widely used in steel structures. In many cases their webs are subjected to transverse compression resulting from the effect of adjacent members or from the concentrated transverse loads. Resistance of the member web to transverse compression is affected by number of aspects, e.g. structural solution of the joint (welded or bolted with end plate), possible longitudinal normal stress in the member caused by axial load or bending moment, interaction with shear or effect of local buckling of the web. The paper focuses on specific problem of resistance of the web to transverse compression resulting from transverse load applied close to the unstiffened end of the member. The investigation of the resistance of the web to transverse compression is performed using advanced geometrically and materially nonlinear numerical analysis for various distances of the transverse load from the unstiffened end. The influence of this distance on transverse compression resistance is quantified. Rolled and welded cross-sections of various web slenderness are investigated. The results are, where possible, compared with results obtained from available design standards. [ABSTRACT FROM AUTHOR]

An application of small aerial vehicles is described in this paper which presents an optimization of the camber position ever-changing using models and numerical analysis. During this study, the mechanics performance of a wing must be investigated over a profile of camber of 20 percent length of the chord from edge. The model was initially modelled using a software package and by adjusting the morphing wing system's modularity and reconfigurability. The angle of attack is also explored following a comparative analysis of the mechanics parameters. A considerable effect of morphing flap camber profiles on mechanics performance is observed in the results. As a supplementary validation, we provide an analysis of wind characteristics through ANSYS; we obtain the pressure coefficients, lift (CL), drag (CD), and lift-to-drag ratio (CL/ CD). The correlation between the CL, (CL/CD) and drag cut back simulations for several preferred shapes is analyzed when getting the results. For that reason forward in optimizing the cambered profile when morphing edges because the mathematical analysis associated with it has been shown improvements in CL from 15% to 30% when morphing edges. [ABSTRACT FROM AUTHOR]

This paper arose from the teaching of Models in Biology to take a new approach to problems they are familiar with, to come up with an articulate verbal model after a mental effort, to express it in rigorous mathematical terms, to solve corre-sponding equations (with the help of computers), and to analyze and interpret experimental data in terms of their (mathematical) models. We will investigate a mathematical model of branching by solving a system of partial equations (PDEs). The results will describe the success or failure of the growth of the fungus species studied, and we used some codes (pplane7, Pdepe) in numerical analysis because direct mathematical solution was difficult. [5] Tip death due to hyphal death, dichotomous branch-ing [ABSTRACT FROM AUTHOR]

The ABC flow for the stationary three dimensional Navier-Stokes equations is considered. The problem is formulated on the full periodic domain. The main object of the paper is the preliminary analysis of the solution curves and location of disconnected solutions from the main branch (stationary trivial solution defined by the forcing term in the ABC problem setup). It is noted that the disconnected solutions exist for two variants of the problem parametrization: A = B = C = 1 and A = B = 1,C = 2. [ABSTRACT FROM AUTHOR]

Members of double-symmetrical open cross-sections are widely used as columns in steel structures. In many cases columns are subjected not only to axial force but also local transverse force due to effect of beams connected to the columns. It results in compression in the column web that should be verified in the structural design. Current standard for design of joints in steel structures provides basic information for verification of this joint component. The design resistance of column web in compression is given as yielding resistance or, based on relative slenderness of the web, buckling resistance which takes into account buckling and crippling of the web that are considered using reduction factor. The complex behaviour of the column web in compression is affected by number of aspects, e.g. structural solution of the joint (bolted, welded, with or without end plate), level of normal stress resulting from axial force or possible interaction with shear. The paper focuses on selected aspects influencing the resistance of the column web in transverse compression and summarizes results of advanced geometrically and materially nonlinear numerical analysis which are compared with results determined using provisions in the standards. The numerical analysis was performed using computation system based on finite element method. As it is considered that the resistance of the column web in transverse compression is influenced also by the geometric properties of the cross-section including geometry of the flange-web transition, both rolled and welded cross-sections with various values of web slenderness were selected for the analysis. Along with evaluation of the results obtained in the frame of the study, suitability of different types of numerical models for investigation of this problem is discussed. [ABSTRACT FROM AUTHOR]

The paper reports a numerical campaign in which two point-supported elements made of laminated glass were investigated with FEM. The first element was a horizontal roof panel 3000×1500 mm2 supported at six locations and subjected to static, uniformly distributed load. The second element was a free-standing glass balustrade 900×1900 mm2 mounted to the structure by four-point supports and subjected to soft body impact. Four types of fixings were investigated: disk fixing, countersunk fixing, bonded disk fixing and countersunk fixing on a single layer. The analysis was aimed at the investigation of the influence of different point supports on the stress in the glass. For a selected connector, a comparative analysis using the FE software and an analytical method presented in DIN 18008-3 was performed. In addition, an analysis of a positive influence of a continuous handrail on the behavior of a row of free-standing glass balustrades was investigated. [ABSTRACT FROM AUTHOR]

The following paper presents numerical analyses and laboratory tests used for analyzing the impact of exploitation damage to the main structural members of the scaffolding frame system. The presence of inevitable defects reduces the strength of material compared to the theoretical strength. Numerical analysis preceded by own laboratory research allows you to describe precisely the behavior of the element. Performing a series of calculations gives information on the impact of the damage size and location on the bearing capacity of the scaffolding frame. [ABSTRACT FROM AUTHOR]

The main aim of this paper is an experimental and numerical analysis of the dynamic behavior of an active rotor with three composite blades. The study focuses on developing an effective FE modeling technique of a macro fiber composite element (denoted as MFC or active element) for the dynamic tests of active structures. The active rotor under consideration consists of a hub with a drive shaft, three grips and three glass-epoxy laminate blades with embedded active elements. A simplified FE model of the macro fiber composite element exhibiting the d33 piezoelectric effect is developed using the Abaqus software package. The discussed transducer is modeled as quasi-homogeneous piezoelectric material, and voltage is applied to the opposite faces of the element. In this case, the effective (equivalent) piezoelectric constant d33 * is specified. Both static and dynamic tests are performed to verify the proposed model. First, static deflections of the active blade caused by the voltage signal are determined by numerical and experimental analyses. Next, a numerical modal analysis of the active rotor is performed. The eigenmodes and corresponding eigenfrequencies are determined by the Lanczos method. The influence of the model parameters (i.e., the effective piezoelectric constant d33 *, voltage signal, angular velocity) on the dynamics of the active rotor is examined. Finally, selected numerical results are validated in experimental tests. The experimental findings demonstrate that the structural stiffening effect caused by the active element strongly depends on the value of the effective piezoelectric constant. [ABSTRACT FROM AUTHOR]

Since the first paper published in 2005 Isogeometric Analysis (IGA) has gained strong interest and found applications in many engineering problems. Despite the advancement of the method, there are still far fewer software implementations comparing to Finite Element Method. The paper presents an approach to the development of data structures that can support multi-region IGA with local mesh refinement (patch-based) and possible application in IGA-FEM models. The purpose of this paper is to share original design concepts, that authors have created while developing an IGA package, which other researchers may find beneficial for their own simulation codes. [ABSTRACT FROM AUTHOR]

This paper presents modelling of both single and double-phase powder sintering processes at the macroscopic level. In particular, its constitutive formulation, numerical implementation and numerical tests are described. The macroscopic constitutive model is based on the assumption that the sintered material is a continuous medium. The parameters of the constitutive model for material under sintering are determined by simulation of sintering at the microscopic level using a micro-scale model. Numerical tests were carried out for a cylindrical specimen under hydrostatic and uniaxial pressure. Results of macroscopic analysis are compared against the microscopic model results. Moreover, numerical simulations are validated by comparison with experimental results. The simulations and preparation of the model are carried out by Abaqus FEA - a software for finite element analysis and computer-aided engineering. A mechanical model is defined by the user procedure "Vumat" which is developed by the first author in Fortran programming language. Modelling presented in the paper can be used to optimize and to better understand the process. [ABSTRACT FROM AUTHOR]

Wireless Sensor Network (WSN) has been widely used for monitoring where sensors are deployed to operate independently to sense abnormal phenomena. Most of the proposed environmental monitoring systems are designed based on a predetermined sensing range which does not reflect the sensor reliability, event characteristics, and the environment conditions. Measuring of the capability of a sensor node to accurately detect an event within a sensing field is of great important for monitoring applications. This paper presents an efficient mechanism for even detection based on probabilistic sensing model. Different models have been presented theoretically in this paper to examine their adaptability and applicability to the real environment applications. The numerical results of the experimental evaluation have showed that the probabilistic sensing model provides accurate observation and delectability of an event, and it can be utilized for different environment scenarios. [ABSTRACT FROM AUTHOR]

Carl David Tolmé Runge was a German mathematician. In 1895 he brought about a revolution in the science of what has become numerical analysis. Numerical approximation to the solution of ordinary differential equations had been based on the method of Euler. but it suffered from a low convergence rate. Runge's discovery in his 1895 paper brought the so-called order from 1 up to 2. This development was followed within a few years by extensions of his techniques which brought the possible order up to 4. The analysis of order conditions for early work on Runge-Kutta methods was based on the use of a scalar test problem y' = f (x, y), but for high order method derivations and other applications, it is appropriate to use instead an autonomous high dimensional test problem y' = f (y). Because of the special requirements of stiff problems, implicit Runge-Kutta methods have an importance of their own and these developments are briefly surveyed. The intricate manipulations required to analyse the order of complicated methods has lead to an algebraic theory and its formulation as B-series. Finally, the special applications to structure-preserving algorithms are introduced. [ABSTRACT FROM AUTHOR]

This paper reports a new numerical method based on Bernoulli polynomials for the solution of Helmholtz equations. The method uses matrix forms of Bernoulli polynomials and their derivatives by means of collocation points. Aim of this paper is to solve Helmholtz equations using this matrix relations. [ABSTRACT FROM AUTHOR]

This paper provides a design procedure for the bypass subline in a mixed-model assembly line. The bypass subline is installed to reduce the effect of the large difference in operation times among products assembled together in a mixed-model line. The importance of the bypass subline has been increasing in association with the rising necessity for efficiency and flexibility in modern manufacturing. The main topics of this paper are as follows: 1) the conditions in which the bypass subline effectively functions, and 2) how the load should be distributed between the main line and the bypass subline, depending on production conditions such as degree of difference in operation times among products and the mixing ratio of products. To address these issues, we analyzed the lower and the upper bounds of the line length. Based on the results, a design procedure and a numerical example are demonstrated. [ABSTRACT FROM AUTHOR]

The analytical model for predicting the pressure at any point in a flow string is essential in determining optimum production string dimension and in the design of gas-lift installations. This information is also invaluable in predicting bottom-hole pressure in flowing wells. A variety of model on bottom-hole pressure in flowing wells have been reported in the literatures. Most of the early models on pressure drop in the flowing wells were based on single phase flowing wells, even the recent investigators treated the multiphase (liquid and gas phase) as a homogenous single phase flow without accounting for dissolved gas in oil. This paper present a modification of previous models for single phase flowing gas wells and the model was adapted to predict the pressure drop in multiphase flowing wells. In this paper, we can solve numerically to obtain the pressure upstream of the nozzle in two phase flow. The key operational and fluid/ pipe parameters which influence the degree of pressure drop in flowing wells are identified through the modification. [ABSTRACT FROM AUTHOR]

Control points are geometric primitives that play an important role in designing the geometry curve and surface. When these control points are blended with some basis functions, there are several geometric models such as Bezier, B-spline and NURBS(Non-Uniform Rational B-Spline) will be produced. If the control points are defined by the theory of fuzzy sets, then fuzzy geometric models are produced. But the fuzzy geometric models can only solve the problem of uncertainty complex. This paper proposes a new definition of fuzzy control points with linguistic terms. When the fuzzy control points with linguistic terms are blended with basis functions, then a fuzzy linguistic geometric model is produced. This paper ends with some numerical examples illustrating linguistic control attributes of fuzzy geometric models. [ABSTRACT FROM AUTHOR]

This paper discussed the used of an open source sofware called Scilab to develop a heat simulator. In this paper, heat equation was used to simulate heat behavior in an object. The simulator was developed using finite difference method. Numerical experiment output show that Scilab can produce a good heat behavior simulation with marvellous visual output with only developing simple computer code. [ABSTRACT FROM AUTHOR]

This paper numerically investigates the physical behavior of deep geological structures in the Yakutsk-Vilyui large igneous province. The geophysical data of "Kimberlit-1981" profile was used to create the computer structures of the researched region. To analyze the plastic deformation, the Nikolaevskiy elastic-plastic model was used. For investigating the geotectonic stress processes, the strength model "jelly sandwich", which operates with cohesion and coefficient of internal friction, was adapted to the Nikolaevskiy model. The depth analysis of plastic strain and the stress state was performed. It is shown that the strain localization partially accord with the orientations of faults obtained from the geophysical data of "Kimberlit-1981. The distribution of stress state is conditioned by the model "jelly sandwich". The distribution of pressure has a quasi-monotonic increase with depth and local disturbances caused by strain localization in the shear bands in the depth layers of Earth's crust. These results can be of use by geologists to evaluate the metamorphism of rocks. [ABSTRACT FROM AUTHOR]

Diffusion equations in multicomponent environments, as parabolic evolutionary systems, have many physical and engineering applications; another their application was accentuated in 2020 due to the Covid19 infection. This short paper demonstrates the possibility of numerical analysis of direct and inverse problems of this type using some algorithms from computational heat, mass, etc. transfer, with special nonlinear terms originated in mathematical biology. One simple example sketches the benefits and hazards of such prediction for the MATLAB-based analysis of readily available Covid19 spread data from the Czech Republic. [ABSTRACT FROM AUTHOR]

Nowadays, 3-D printing (or additive manufacturing) is a widely used technique in different branches (e.g. public healthcare, consumer goods, weapons development etc.) to produce various objects and products. In the last years, 3-D printing has also begun to be used in the fields of civil engineering. Today, the use of 3-D printing in civil engineering takes different forms. Authors of this paper focus on the use of 3-D printing for the development of plastic formworks for concrete which can substitute steel reinforcement. This technology has its limitations for now, but it is still worthy for the numerical investigation which will be necessary for practical designing of concrete structures with 3-D printed plastic reinforcement in future. For this reason, the numerical investigation of mechanical behavior of concrete element shaped and reinforced by 3-D printed formwork is performed within this paper. The flexural strength test is numerically simulated for this purpose. The result of the best numerical simulation is compared with the result of the practical flexural strength test which was obtained from the former experimental investigation. Based on this comparison, provisional insufficiencies of the used numerical approach are discussed. [ABSTRACT FROM AUTHOR]

Recently helicon plasma sources are of particular interest for plasma material interaction under fusion conditions. This paper is devoted to study the effect of the antenna type, operating frequency and static magnetic field intensity on power absorption in Helicon Physics Prototype eXperiment(HPPX). The results show that Half Helix antenna can generate non-axisymmetric RF energy which can produces higher electron density. When the antenna work frequency is 13.56MHz, helicon plasma can produce better absorption effect. The external constrained static magnetic field is introduced into the plasma, there exist multiple local peaks for certain magnetic field strength, and the absorption effect increases with magnetic field strength overall. This work can serve as an important reference for the related physical experiments of HPPX device in the future. [ABSTRACT FROM AUTHOR]

In the present paper, a time-dependent numerical model for the design of a climatic chamber is been developed. The reference is made to the design of a chamber suitable for tracked and wheeled tractors, i.e. having measures 5x8x4 m³ (length x width x height). In order to support the theoretical predictions for the design, a numerical analysis is performed by employing Matlab-Simulink, a software package devoted to the simulation of the behavior of transient systems. Reference is made to simulate the air conditioning system of the tractor in both the two cases: the “winter case” and the “summer case”, as prescribed by the ISO 14269-2:1997 standard. In fact, in order to achieve the compulsory European type approval for tracked and wheeled agricultural tractors, the European Regulation 167/2013 has to be considered and the approval test for heating, cooling and conditioning systems requires experimental measures according to the European Delegated Regulation EU 2015/208. In detail, the heating and cooling devices have to be experimentally tested basing the measurements on the procedure foreseen in the ISO 14269-2:1997 standard, that provides a particular heavy weather conditions, both for summer and winter cases, and for long periods of time. For the mathematical model, the climatic chamber is represented by 5 blocks, and balance equations are written to simulate the systems in both climate conditions. [ABSTRACT FROM AUTHOR]

The Fourier series, Laplace and Fourier transforms are applicable for the solution of parabolic type involutory differential problem with constant or polynomial coefficients. In the present paper, the first and second order of accuracy difference schemes for the numerical solution of the initial boundary value problem for one dimensional parabolic type involutory partial differential equation are presented. Numerical results are given. [ABSTRACT FROM AUTHOR]

In this paper, the dynamics of convergence rate is investigated for the approximations depending on the changes of the stiffness coefficient of the elastic fixation. The results of the numerical analysis show that with increasing of stiffness coefficient (parameter a) of the elastic fixation the radius of convergence of Neumann series increases, and the convergence rate of the approximations to the exact solution accelerates. [ABSTRACT FROM AUTHOR]

Numerical computation packages are widely used both in teaching and research. These packages consist of license (proprietary) and open source software (non-proprietary). One of the reasons to use the package is a complexity of mathematics function (i.e., linear problems). Also, number of variables in a linear or non-linear function has been increased. The aim of this paper was to reflect on key aspects related to the method, didactics and creative praxis in the teaching of linear equations in higher education. If implemented, it could be contribute to a better learning in mathematics area (i.e., solving simultaneous linear equations) that essential for future engineers. The focus of this study was to introduce an additional numerical computation package of Scilab as an alternative low-cost computing programming. In this paper, Scilab software was proposed some activities that related to the mathematical models. In this experiment, four numerical methods such as Gaussian Elimination, Gauss-Jordan, Inverse Matrix, and Lower-Upper Decomposition (LU) have been implemented. The results of this study showed that a routine or procedure in numerical methods have been created and explored by using Scilab procedures. Then, the routine of numerical method that could be as a teaching material course has exploited. [ABSTRACT FROM AUTHOR]

In this paper, the simple fractional iterative differential equation will be the focus of study Dβv(s) = vn(s); v(s0) = a: where s0; v0 ∈ I = [0, b], and 0 < β < 1. One class of the iterative fractional differential equations is the simple iterative fractional differential equation. In this paper, the local existence and uniqueness results for the fractional order of degree n of simple iterative fractional differential equation are proven and the solutions found by using power series. [ABSTRACT FROM AUTHOR]

Conjugate gradient (CG) methods have been recognized as an interesting technique to solve optimization problems, due to the numerical efficiency, simplicity and low memory requirements. In this paper, we propose a new CG method based on the study of Rivaie et al. [7] (Comparative study of conjugate gradient coefficient for unconstrained Optimization, Aus. J. Bas. Appl. Sci. 5(2011) 947-951). Then, we show that our method satisfies sufficient descent condition and converges globally with exact line search. Numerical results show that our proposed method is efficient for given standard test problems, compare to other existing CG methods. [ABSTRACT FROM AUTHOR]

Recently many researches try to develop and improve the Conjugate Gradient (CG) methods because of its convergence properties and low computation costing. In this paper, another CG coefficient (.k) will be proposed which is categorized as modification in such a way to improve the performance of the classical CG methods. This paper is focused on generating (.k) with several desirable properties: (1) generate descent search direction at each iterations; and (2) converge globally by using strong Wolfe line search. Numerical comparisons of three CG methods show the robustness and the efficiency of the new method in solving all given problems. [ABSTRACT FROM AUTHOR]

This paper considers Newton-MSOR iterative method for solving 1D nonlinear porous medium equation (PME). The basic concept of proposed iterative method is derived from a combination of one step nonlinear iterative method which known as Newton method with Modified Successive Over Relaxation (MSOR) method. The reliability of Newton-MSOR to obtain approximate solution for several PME problems is compared with Newton-Gauss-Seidel (Newton-GS) and Newton-Successive Over Relaxation (Newton-SOR). In this paper, the formulation and implementation of these three iterative methods have also been presented. From four examples of PME problems, numerical results showed that Newton-MSOR method requires lesser number of iterations and computational time as compared with Newton-GS and Newton-SOR methods. [ABSTRACT FROM AUTHOR]

In this paper, we study the shape preserving interpolation for positive data using a rational quartic spline which has a quartic numerator and linear denominator. The rational quartic splines have GC1 continuity at join knots. Simple data dependent constraints are derived on the shape parameters in the description of the rational interpolant. Numerical comparison between the proposed scheme and the existing scheme is discussed. The results indicate that the proposed scheme works well for all tested data sets. [ABSTRACT FROM AUTHOR]

This paper is concerned with a Holling-II stage-structured predator-prey system (in which predators are divided into immature and mature predator) with fear effect. The aim is to explore how parameters factors influence on the bifurcation behavior of the model. The theoretical works showing that transformation rate and maximum attack rate can lead to saddle node bifurcation, and transcritical bifurcation. In addition, fear rate may lead to occurrences a Hopf-bifurcation near positive equilibrium point. Numerical analysis ensures accuracy of the theoretical outcomes and testifies the existence of local bifurcations near the non-trivial equilibrium points. [ABSTRACT FROM AUTHOR]

Crop imagery is categorized into 3 different types, which are near-field images, satellite images and drone-based images. All these image types can be processed to determine crop growth, crop diseases and finally crop yield. Different algorithms have been proposed over the years which determine one or more of these parameters using a series of image segmentation, feature extraction, feature selection, classification and post-processing steps. Each of these steps requires a specialized set of algorithms to be employed to design an effective crop-image processing system. Due to the wide variety of algorithms present in the given field of work, the selection of the most optimum algorithm set for a given application is often ambiguous. For instance, if an application is trying to process satellite imagery, then identification of the best image-fusion methods for effective classification requires a lot of research, and thus increases the delay in designing the system. To reduce this ambiguity, this paper reviews these algorithm sets which identify the best techniques in terms of statistical parameters for a given application. Accuracy and error rates have been compared between different algorithms to give a clear idea about the performance of these algorithms. This comparison also allows researchers to identify best practices in terms of algorithm selection. [ABSTRACT FROM AUTHOR]

The paper deals with numerical modeling of slab in interaction with the subsoil. A 3D computational model and numerical analysis are focused primarily on taking into account physical nonlinearity. The fracture-plastic material model is used, where the parametric study is performed with different input parameters of fracture energy. For nonlinear calculation the Newton-Raphson method was chosen. The performed calculations are compared with the experiment of a fibre-reinforced concrete slab with dimensions of 2000 x 2000 mm. The slab was tested on a specialized testing device, which allowed to evaluate the load - displacement diagram. Calculation results are compared with the experimental data and finally comparison is performed. [ABSTRACT FROM AUTHOR]

The paper deals with numerical analysis of pretensioned experimental beams exposed to loading test. Pretensioned beams were designed as model structural specimens, adjusted to real dimensions of slab bridge beams, made of common concrete and new variant of high performance concrete with compressive strength about 100 MPa. Experimental beams were exposed to loading test for verification of load bearing calculation model, as compressive strength of HPC is on the border or oversteps the validity of current design codes. Numerical analysis was performed using software IDEA statica which enables to determine cogent effect of prestressing with respect to changes in time related to construction stages. Failure and cracking load appointed on the basis of experimental loading and numerical analysis are compared and discussed. [ABSTRACT FROM AUTHOR]

Determination of the current condition, load-bearing capacity, and reliability of the existing structures is often a greatly time-consuming and complex task. There are two main approaches how to evaluate the condition of existing structures and find out the response of the structure under acting loads. The first method is to perform an analytical or numerical analysis of the structure. This method is often used, but the accuracy of the outcomes deeply depends on the input parameters used in the analysis. Alternatively, if the input parameters are not clearly known or the exact behavior of the structure during loading is required, the best way how to evaluate the structure is to perform a full-scale load test. This paper describes the process of preparation, execution, and evaluation of the in situ full-scale load test of the bowstring arch reinforced concrete bridge built between the 1920s and 1930s damaged during the Second World War, repaired in the 1970s with no further maintenance later on. [ABSTRACT FROM AUTHOR]

This paper presents the description of the preparation of aggregate irradiation experiment including the choice of sample types and preliminary numerical prediction of aggregate RIVE and damage under defined conditions for the research reactor LVR-15. Ten different samples from four countries were selected for the experimental investigation. The preliminary numerical analysis was performed for granite as the aggregate with the highest radiation-induced volumetric expansion (RIVE). Based on the prediction, the highest RIVE of 4.54 % at high-dose neutron fluence (0.585·1020 n/cm2, with energy E>10 keV) is expected. Thus, taking into account the sample size, the inner diameter of the irradiated capsule should be about 11 mm. The aggregate samples with the highest RIVE (granite) are expected to be damaged significantly even after irradiation to low-dose neutron fluence (0.208·1020 n/cm2, with energy E>10 keV) which will be captured during the post-irradiation examination. [ABSTRACT FROM AUTHOR]

In this study, the turbulent flow over symmetrical and unsymmetrical airfoils was investigated numerically at different inlet velocities. The airfoils chosen for the simulation are symmetrical (NACA 0015) and unsymmetrical (NACA 4412), which are the most conventional four-digit and widely used airfoils. These airfoils are vastly used for various applications such as aircraft wings, wind turbine blades, etc. While both of these airfoils were subjected to the same fluid principle, it gave contradictory results in their aerodynamic behavior. In this paper, two different meshing techniques were used for the airfoils and the numerical analysis of NACA 0015 and NACA 4412 was carried out to study their aerodynamic behavior. A 2D steady-state incompressible turbulent flow is used to model the computational issue. The performance of the turbulence model is also reviewed. The lift and drag coefficients of the airfoils were numerically measured using the k − ε turbulence model. This study briefs the aerodynamic flow characteristics of both airfoils and evaluates the pressure and velocity contours, lift force and drag force. [ABSTRACT FROM AUTHOR]

The novel coronavirus disease 2019 (COVID-19) has shown the danger that can be caused by small, airborne and contagious virus particles such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To prevent the mass spreading of such viruses, the use of electromagnetic waves could be used to combat the spreading of the virus. Particularly, the waves could force any virus particles to oscillate in resonance with the frequency of the wave and destroy themselves before the virus would enter the respiratory system. This paper describes the use of numerical simulations to analyze the effects of exposing a SARS-CoV-2 particle to electromagnetic waves at a range of frequencies and to determine which frequencies have the potential of causing resonance within the virus which would yield to the maximum energy absorption. Such technique could be utilized in preventive/protective devices and disinfection equipment. [ABSTRACT FROM AUTHOR]

Castellated beams are well contemporarily ascribable to their structural applications. The Castellated beams are manufactured by fragmenting hot-formed rolled section that is of I shape in then it is welded together. The numerical analysis is performed using ABAQUS software. Consequently flexural, shear behavior of Castellated beams, various size and shape of openings provided, depth of openings, usage of different kinds of stiffeners, columns with and without web openings are the attempts made up in different journal papers and he researchers. It is also found that the Finite element analysis of the beam shows better results. [ABSTRACT FROM AUTHOR]

The vortex rope in a hydro turbine draft cone is one the main and strong sources of pulsations in non-optimal modes of hydro turbine operation. The subject of this paper consists in development of a numerical procedure to study the absolute/convective hydrodynamic instability of the swirl flow downstream the Francis turbine runner by means of parallel computing. As an alternative to classical methods as finite volume and finite element methods, the present paper proposes a new approach of the analysis of the swirling flow based on the method of orthogonal decomposition. This method has the benefit of reducing the computational time compared to other techniques. The important point of this paper is that highlights the validation of the numerical results computed by means of the proposed technique with corresponding published results. Moreover, the algorithm provided the growth rate curve as function of mode number both in absolute and convective analysis, some presumptions on the streamwise development of the instability in the vortex thus being made. [ABSTRACT FROM AUTHOR]