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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]

Many soft robotic structures are developed using soft fluidic actuators, which are developed using elastomeric materials such as silicon rubber. Due to the complicated geometries and nonlinearity in the soft actuator's design, it becomes very difficult to predict their behavior analytically. Finite Element Method (FEM) analysis is a numerical technique which is utilized to predict the stress, strain, and deformation in such actuators design. In this paper, bending behavior of two soft pneumatic fingers with varying wall thickness are designed and compared. Bending angle configurations of the designed fingers are evaluated at 30 and 40 kPa of actuating pressure. The obtained results show that to achieve a bending angle of 116 degrees, finger 2 requires 40 kPa of actuating pressure whereas finger 1 requires 80 kPa. Due to low stiffness of finger 2 as compared to the finger 1, which is resulted due to thickness variation in the two designed fingers, much higher bending angle configuration can be achieved at very low pressure for the finger 2. [ABSTRACT FROM AUTHOR]

The presence of ducts surrounding wind turbines improves the performance by accelerating the wind at the entrance. The objective is to find a duct that produces improved wind power with low duct drag forces. Numerical analyses were carried out on the flow past a ducted wind turbine using computational software ANSYS Fluent. In this paper, the performance of six different ducts surrounding the wind turbine was compared. The duct geometries considered were S1) E423 aerofoil duct of chord length (L) / (throat diameter) D ratio=0.225 at 37.5 °, S2) duct with leading-edge slot, S3) duct with trailing edge slot, S4) duct with trailing edge flap, S5) duct with converging section and S6) duct with multiple slots. The performance improvement was evaluated using the average velocity in front of the blade plane and power output. The flow characteristics of conventional turbines and six ducted turbines were discussed. It was found that duct with trailing edge flap had shown higher power output with higher drag. The results indicate that the duct with multiple slots in the duct's circumference had equivalent power output to a fully closed duct. [ABSTRACT FROM AUTHOR]

A screw-type centrifugal pump is a kind of non-clog type pump and has been widely used, for instance, for drainage of rainwater as well as slurries and mud in sewage control systems. In order to avoid choking the impeller passage with the congestion of solids, the impeller is designed to have a wide passage which configuration is screw formed by a three-dimensional spiral blade added to a conical hub cone. This paper presents the results of pressure and velocity fields in centrifugal pump with single blade. In the pump tested, a volute with circular cross-section was used. The prediction of radial thrust is important and useful information for the safe operation and design of the bearings. Particularly, the fluctuation of radial thrust in this pump is large because of one blade. The tests were carried out for several flows, including above and below the nominal one. Effects of the time-steady flow in a single-blade pump are investigated by numerical method CFD (Computational Fluid Dynamics), specifically discussing the conditions of internal flow such as velocity and pressure. For a numerical approach the three-dimensional, viscous, unsteady flow field in the pump has been achieved by solving the unsteady Navier-Stokes equations (URANS) with a commercial code. Commercial code ANSYS CFX was used for the calculations. [ABSTRACT FROM AUTHOR]

In March 2021, an ultra-large container ship, the M.V Ever Given, was stranded at the southern part of the Suez Canal and blocked the two ways of the canal and subsequently deferred more than 100 vessels traversing between Asia and Europe. The blockage was cleared within five days; however, notwithstanding the short period, the incident had caused huge world trade losses. One of the prevailing causes of ship groundings is manoeuvring difficulties due to ship-bank interaction. This study is therefore aimed at understanding the effect of the ship's size on the ship-bank interaction in a canal. In this paper, a mathematical model was developed to study the effects of ship-bank interaction on the manoeuvring performance of a large container vessel in a canal, with different ship parameters. The results showed that the increase in size and speed significantly influenced the bank-effect and contributed to the eventual grounding of the ship. The effect of rudder surface area to counter the bank-effect was also investigated. This study showed that increasing the rudder surface area can improve the counter-actions of the ship against the bank effect. [ABSTRACT FROM AUTHOR]

The ship hull is the basic underlying structure of ship that makes the ship water tight or water proof. Meaning the hull prevents the water from entering the cargo, machinery.so hull are usually made of materials that have high mechanical properties, impact less and less water absorption qualities.conventional hull materials used where steel wherein the boat becomes too heavy in considerations with its high strength, abrasion resistance etc.so composite materials where used which give a single structure offering solutions of strength, durability, light speedy, watertight structure in the manufacturing of boats for past 50 years. This novel paper focuses on a comparative study of composite materials previously used with further improvements in characteristics such as increased strength, ease of manufacturing, more impact resistance and increase is load tensile and compressive load bearing characteristics. The composite materials comprising of GFRP+graphite powder and GFRP+Aluminum powder was tested and analyzed experimentally for enhancement in various mechanical properties, structural and water absorption capabilities, and optimum designs further obtained. Even though experimental analysis where performed numerical analysis of these composite models is yet to done which would lead to determining more efficient structures with best materials used. [ABSTRACT FROM AUTHOR]

Investigation still on board for finding the best techniques to develop the thermal and hydraulic performance of the heat exchanger. One of the useful, practical methods for finding the modification is the numerical analysis. This numerical analysis was obtained by modelling and simulation using ANSYS FLUENT software. In this present work five elements were modelled and simulated of three different configuration models, helical tape, rectangular and triangular straight strip inserts were inserted inside the inner pipe. This simulation was employed according to the working operation conditions of the real practical double pipe heat exchanger. The results show that, the helical tape configuration demonstrated the effective enhancing technique of the heat transfer, which is improving the thermo-hydraulic performance of this type of heat exchanger in this study. According to this work, the technique of studying numerically the design enhancement of the heat exchanger can produce an excellent result and gives a good recommendation to transfer it into practical work. [ABSTRACT FROM AUTHOR]

: Tilt of G+4 RCC buildings with isolated foundation systems due to differential settlement is one of the common problems, which affects the overall structural stability of the real life buildings. Tilt may be caused due to excavation of adjacent plots of the building without adequate lateral support, poor workmanship, overloading on cantilevered portions above first floor level, improper design and construction etc. The overall stability of the tilted RCC buildings mainly depend on the type & amount of tilt along with the building configuration. NDT results of concrete members are nowadays practiced extensively in real life situation to evaluate the strength and quality; which are sparse to assess the stability of the structures as these are of qualitative and piecewise manner. Additionally, the seismic force; which depends on the seismic zone of the building site, adversely affects the building stability. Thus, the parametric study on the stability of various buildings subjected to different type & extent of tilts; situated on different seismic zones seems to be significantly important. This present paper aims to assess the stability of various G+4 RCC buildings of same plan area & height, with different number of bays in their structural system, located at different seismic zones; when subjected to different extent of uniaxial and biaxial tilts. Different G+4 RCC buildings with different structural configurations and located at different seismic zones; subjected to different types & amount of tilt are duly considered in the finite element framework of SAP2000 for the parametric numerical analyses. Along with type & extent of tilt, it is found that building configuration and zone of seismicity significantly affects the overall stability of these multistoried tilted buildings. The present study may have a great scope for safety assessment and upgradation of real life medium high RCC building structures subjected to tilt. [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]

Even though symmetrical airfoil has less lift-drag ratio and the undesirable stall characteristics it has been used in the rotary wing applications. Increasing the aerodynamics efficiency by using the different flow control methods are the important research in recent years. Amplifying the lift coefficient without causing any negative impact on the drag coefficient will create the great impact on aeronautical domain. Hence this paper objective is by using cylinder rotation- an active flow control method to improve the aerodynamic efficiency over the airfoil. To get the optimum values of lift and drag coefficient the flow parameters, velocity ratios of the cylinder Vc / V∞ and the location of the cylinder have been used. The model of the NACA 0012 airfoil with cylinder is developed by using Inventor and the numerical analysis were carried out by using Ansys fluent. Analysis was carried out for the velocity ratios of 0.5,1 and 2 by placing the cylinder at the chordwise locations of 10% to 50% of its length. When compared the results of NACA 0012 airfoil with cylinder and without cylinder there is a significant growth in aerodynamic efficiency and delayed in stall angle. Generally, the performance was increase in the ratio of cylinder rotation speed Vc to the freestream speed V∞. There appears to be an optimal location for the rotating cylinder which gave quite promising results. [ABSTRACT FROM AUTHOR]

During the optimal design of dynamic mechanical systems operating in aggressive external media, special attention should be paid to issues related to computational costs and estimates of the results obtained. Metal structures designed to operate in corrosive external media are considered as the object of research. The main computational costs are incurred in calculating the constraint function in the optimization problem (or in solving the problem of predicting the durability of corroding structures). The authors propose a modification of the method of corrective functions based on polynomial approximation of structural elements when solving the strength problem. The approach consists of two stages: function decomposition and use of the regulator of a neuro-fuzzy network to obtain error estimation. The neurofuzzy network uses geometric characteristics of the structure, aggressive medium parameters, stresses in the system elements, and third-degree polynomial coefficients to determine the problem solution error. The obtained approximate solution and its error allow obtaining a more exact solution. The use of adaptive network fuzzy inference systems allowed the authors to significantly reduce the computational cost and obtain numerical solutions with a given accuracy. The results obtained during numerical experiments confirm the correctness of the chosen approach. [ABSTRACT FROM AUTHOR]

The method of thermal diagnostics of friction (TDF) has been developed in detail for radial sliding bearings with rotary motion of the shaft, which makes it possible to determine the friction force from temperature data.The possibility of determining the frictional moment by measuring the temperature is theoretically shown in the case of the swinging motion of the shaft using a two-dimensional mathematical model of the thermal process. The use of a two-dimensional model limits the use of the TDF method for solving practical problems. In this paper a three-dimensional model of the thermal process is proposed, taking into account the rotating speed of the shaft for a sliding bearing operating in a reciprocating-rotational mode. Taking into account the speed of the shaft movement leads to a significant increase in the calculation time, which is not always desirable for TDF based on solving the inverse problem of heat transfer. Determining the conditions under which it is possible to disregard the speed of the shaft in the thermal process model is an urgent problem. The method for determining the kinematic conditions for accounting for the speed of the shaft in the mathematical model of the thermal process is proposed on the basis of a numerical analysis of the unsteady three-dimensional temperature field in a radial self-lubricating sliding bearing. The results obtained can be used for TDF in real sliding bearings. [ABSTRACT FROM AUTHOR]

The purpose of this research is to evaluate static and dynamic stability characteristics of a sailplane in flight. In the current paper - part 1, the static stability is studied. Conventional ways of determining static stability characteristics of an airplane are based on semi-analytical models comprised of equations and formulas, which are not easily applicable in the design case of an aircraft type such as that of a sailplane, due to the relatively high aspect ratio, lack of thrust force, weight requirements and complex geometry. Instead a new method using CFD analysis is developed. A sequence of numerical analyses is executed in Ansys - Fluent. Steady state cases are used. Exact numerical results are obtained for all three longitudinal, directional and lateral stabilities. All of the data obtained from the CFD studies is used in the design process of a sailplane. All results from the proposed method are confirmed by analysing existing aircraft of the same type and mission. [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 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]

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]

The paper presents two-dimensional model of gas filtration flow in a porous medium as well as efficient computational algorithm. The analysis of performed numerical calculations showed that when the gas filtration parameters and properties are viewed as functions of pressure, then the studying process can be adequately described as a whole and the numerical results correctly reflect its essence. The results of computer calculations were used to substantiate a decision support system for selecting the operating modes of wells in order to obtain optimal and more economical production routine. Computer calculations demonstrated that the longitudinal-transverse directions scheme in some cases may be more preferable than the locally-one-dimensional method. [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]

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]

Novel AZ91 magnesium syntactic foams are a potential choice for temporary biomedical implants. In many cases, holes of various sizes need to be machined on the biomedical temporary implants using the drilling process to facilitate placement of implants inside the human body. In this study, the drilling performance of AZ91-magnesium foam is investigated under different lubrication methods such as dry, wet (Almag® mineral Oil-wet machining), and cryogenic cooling. Drilling experiments were carried out using coated and uncoated titanium aluminium nitride (TiAlN) twist drills on varying volume fractions of AZ91 magnesium syntactic foams (5%, 10%, and 15%) reinforced with hollow alumina microspheres. A three-dimensional, thermo-mechanical finite element-based model for drilling magnesium syntactic foam using AdvantEdgeTM is presented for different lubrication conditions. The numerically predicted machining induced stress from the finite element model showed a compressive stress give a better surface integrity and quality to the machined surface in liquid nitrogen coolant when compared to dry machining. This shows cutting with cryogenic cooling as a sustainable drilling process for AZ91-magnesium syntactic foams. [ABSTRACT FROM AUTHOR]

The consolidation settlement is a general geotechnical problem that occurs due to volumetric compression in the area composed of soft soil. This is because cohesive soils have a much lower hydraulic conductivity, and as a result, the consolidation requires a far longer time to complete. The ground improvement techniques have become the most popular method for construction purposes in soft soil. The application of a variety of ground improvement technologies is the key component of the project from the geotechnical point of view. Prefabricated vertical drain is one of the soft ground improvement techniques that have the advantage of decreasing the overall time required for the completion of the primary consolidation rate of soft soil by providing a drainage path. On the other hand, the stone column could also accelerate the consolidation process and reduce the settlement. Therefore, this study aims to determine the approximate method for modeling a real condition on runway construction. The analysis classical axisymmetric solution for soil parameter has been converted into an equivalent two-dimensional plane strain analysis for soft ground improvement techniques. The finite element method results indicate that the efficient distance pattern of prefabricated vertical drains and stone columns due to preloading installation was performed to accelerate the primary consolidation. In addition, the effect of the stone column has been proven to reduce the settlement due to the preloading installation. The duration of combined technologies during primary consolidation is 50% faster than using stone columns only, and the settlement can reduce 12% due to preloading installation. The result of numerical analysis and field validation has a deficiency of up to 30% to achieve consolidation time up to 90%. The discussion of combined technologies has presented a significant time acceleration along with reducing the settlement due to preloading installation, and some limitations can be developed for future studies. [ABSTRACT FROM AUTHOR]

This work aims to conduct the numerical modeling of airflow distribution in the HVAC unit room for the high-speed train passenger coach. A cubical space measuring 2800 mm x 1900 mm x 600 mm, with solid geometry boundaries of enclosed walls, compartments, and system components, was discretized into the computational domain. Pressure boundary conditions were used as the parameters of airflow inlet and outlet. Heat exchanger and filter components were modeled as porous media, and flow was assumed as ideal gas fluid and taking k-epsilon turbulence model as the governing equation for flow physics transport and transient as well. Some aspects of the availability of unit space sizes, geometry and dimension of system components, space configuration for the sides of fresh, return, supply, and exhaust air ducts, as well as work parameters according to the results of calculations, were taken as input parameters in modeling. Based on the analysis of the results of the HVAC unit space configuration modeling, it was found that the placement of the air sides in the mixing, supply, and condenser compartments, according to the work parameters that meet the design, greatly determined the characteristics of fluid flow, especially pressure distribution and flow recirculation. [ABSTRACT FROM AUTHOR]

In daily human activity, normal walking becomes the most common performed activity. For this reason, many researchers have been adopted normal walking condition to giving actual loading on many hip implants studies. Our recent article intends to conducting deformation study in hip joint bearing during normal walking activity using numerical analysis. 2D model has been established to pursuing deformation analysis on CoCrMo-on-CoCrMo beraring under normal walking condition. Selected phase has been considered to represent whole of normal walking cycle as parameter input in loading. Deformation larger along acted loading with proportional correlation. Distribution of deformation also wider in case of larger deformation. [ABSTRACT FROM AUTHOR]

The article proposes an alternative method for determining the modulus of deformation of fractured - block rock masses weakened by mutually orthogonal systems of joints when the angles of their inclination to the surface of the rock mass (dip angle) change. The deformation of the model of rock mass is considered within the linear section of the deformation curve a=f(ε) (after closing the cracks), provided that the quasi- continuum criterion is met. The values of normal - kn and tangential - ks stiffness are used as elastic characteristics of joints.It is shown that to determine the deformation characteristics of a block medium weakened by systems of joints with different dip angles, it is unlawful to use the laws of mechanics of a continuous elastic body, since the opening of interblock joints is observed when performing numerical experiments. The discrepancy between the results of numerical and analytical calculations is up to 40%. It is proposed to use for these purposes the equation obtained on the basis of the method of experimental planning and regression analysis of the results of numerical modeling. The presented equation allows, depending on three independent factors: the modulus of elasticity of the rock block - Eo, the rock quality designation index - RQD and the dip angles of systems of mutually orthogonal ioints – α, to determine the modulus of deformation of the rock mass. The accuracy of calculations does not exceed 20%, which corresponds to engineering accuracy and can be used at the preliminary stage of engineering structures design. The article presents schemes and graphs of deformation of a block models, characterized by arbitrary selected combinations of values of independent factors. The results of the study also showed that in the presence of anisotropy, the rock mass can be considered as a conditionally continuous, isotropic medium, provided that the anisotropy coefficient does not exceed 1.5. [ABSTRACT FROM AUTHOR]

This work aims to conduct the numerical modeling of airflow distribution in the HVAC unit room for the high-speed train passenger coach. A cubical space measuring 2800 mm x 1900 mm x 600 mm, with solid geometry boundaries of enclosed walls, compartments, and system components, was discretized into the computational domain. Pressure boundary conditions were used as the parameters of airflow inlet and outlet. Heat exchanger and filter components were modeled as porous media, and flow was assumed as ideal gas fluid and taking k-epsilon turbulence model as the governing equation for flow physics transport and transient as well. Some aspects of the availability of unit space sizes, geometry and dimension of system components, space configuration for the sides of fresh, return, supply, and exhaust air ducts, as well as work parameters according to the results of calculations, were taken as input parameters in modeling. Based on the analysis of the results of the HVAC unit space configuration modeling, it was found that the placement of the air sides in the mixing, supply, and condenser compartments, according to the work parameters that meet the design, greatly determined the characteristics of fluid flow, especially pressure distribution and flow recirculation. [ABSTRACT FROM AUTHOR]

A gas-phase deposition is one of the types of additive technologies and is a process of applying a film or coating to the cooled surface, that is, a continuous layer of material that has, among other things, a nanocrystalline structure. Currently, the development of this and other additive technologies has made it possible to apply a variety of coatings with different properties. In most works devoted to the deposition numerical simulation, the features of gas heat exchange with the surface are not taken into account, while the temperature of the surface on which deposition occurs is one of the fundamental factors determining the film structure. In this paper, a numerical model of heat transfer during gas-phase deposition of a material on a cooled curved substrate is constructed, taking into account the specifics of heat exchange of the gas medium. A numerical analysis of the mathematical model is performed, and the influence of various heat transfer mechanisms on the temperature distribution in the substrate being built up is shown. [ABSTRACT FROM AUTHOR]

This paper presents a study based on the probabilistic dynamic model PDM I MDP with application in TCAS. The algorithm for solving PDM is analysed and also it presents the first step focused by discretizing the state space model. The MDP is evaluated to predict the state space at the next time step for the adequate set of operations. The conformity with the least expected cost criterion allows a better action from that state space. The DP algorithm involve all potential trajectories in the state space and features the selection of the most probable trajectory from the global set. The number of potential trajectories increases exponentially in the time horizon, and hence in case of mathematical models, it is not proposed to string each potential trajectory. In the collision avoidance MDP, the number of predictable trajectories exceeds the number of particles in the universe, however DP can establish all the required data in quick numerical computations. If an aircraft equipped with TCAS receives a traffic alert from other aircraft with TCAS, it will broadcast a coordination message report to the other aircraft instructing it to neither descend nor climb, as being most acceptable. If both aircraft will choose conflicting actions simultaneously, the aircraft with the higher rank from identification number needs to turn out the direction of its advisory. In the case study when an aircraft is receiving instructions from another aircraft not to descend or climb it is powerfully advised to do level off. The results of the analysis carried on in this study are consistent with the real time operations. [ABSTRACT FROM AUTHOR]

The paper deals with the numerical simulation of features of most popular up today adaptive signal decomposition techniques, which applied to the signals of the ultrasonic gas flowmeter in pipes with intrusive piezo- transducers with vertical wave penetration and frequency modulated continuum waves. The most attention was paid to the case of small pipe diameters in comparison with the piezo-transducer size (when it has to be considered). Among the investigated methods the most accurate results (with respect to the bias error) was obtained for singular signal analysis (SSA). However, in the trade-off of accuracy to computational complexity, the principal component analysis (PCA) method was recommended to the farther researches. [ABSTRACT FROM AUTHOR]

The importance of beam-to-column joints in the mechanism of force transmission in steel and steel-concrete composite structures is nowadays well recognized. This central role is even more important when the design is performed under seismic and accidental actions. In this framework, a series of tests on end-plate and column flange T-stubs, modelling a flush end-plate beam-to-column bolted connection, were performed at different displacement rates. In addition, numerical FE models were developed and calibrated against the experimental results. This paper, after an overview of the experimental programme, highlights and discusses the main features and outcomes of the numerical analyses. [ABSTRACT FROM AUTHOR]

This paper describes the experience from the experimental and numerical analysis of the hermetic tightness of bubble tower (BT) of the nuclear power plant (NPP) type VVER 440 under the high internal overpressure after 30 years of the performance. The results from the experimental tests were used for the verification of the numerical model of the reinforced concrete structures. There is showed summary of calculation models and calculation methods for the probability analysis of the structural integrity due to extreme overpressure. The tightness testing of the steel internal liner during the NPP performance was realized in accordance of the international standards. The methodology of the probability nonlinear analysis of the concrete structures using new model of the layered shell elements considering the process of the concrete cracking and crushing. [ABSTRACT FROM AUTHOR]

This paper presents a numerical study of the electromagnetic field in a two-phase conductive medium composed of particles and liquid with different electrical conductivity. Different configurations are considered, in which the size of the region and the location and number of particles inside the cell with an electrically conductive liquid vary. Analysis of the results of the numerical experiments gives the characteristic ratios between the cell and particle sizes, at which the boundaries of the region have no impact on the force. It has been found that the force of interaction between two particles depends on the distance between them, and that the electromagnetic force acting on the particles is related to the electrical conductivity of the particles and liquid. The simulation results can be used as a basis for derivation of the constitutive relations needed to study the process of electromagnetic separation. [ABSTRACT FROM AUTHOR]

The paper presents a numerical analysis of the class of mathematical models of linear fractional oscillators, which is the Cauchy problem for a differential equation with derivatives of fractional orders in the sense of Gerasimov-Caputo. A method based on an explicit nonlocal finite-difference scheme (ENFDS) and the Adams-Bashfort-Moulton (ABM) method are considered as tools for numerical analysis. An analysis of the errors of the methods is carried out, it is shown that the ABM method is more accurate and converges faster to an exact solution than the ENFDS method. [ABSTRACT FROM AUTHOR]

This paper presents an approach to calculate the bus voltages of a power system. The steady state performance of the power system is described by a system of nonlinear algebraic equations. The traditional methods for solution are based on numerical analysis. They are failed to converge for the cases of high loading and for ill-conditioned systems due to the singularity of the Jacobian matrix. The proposed approach is based on a chaotic whale optimization Algorithm. The solution of the system of nonlinear algebraic equations is tackled as an optimization problem. The proposed algorithm is applied to a heavily loaded standard systems where the traditional method fails to get a steady-state solution. Also, the presented algorithm can be applied to obtain the solutions of a system under large motor starting. The results obtained is an indication of the effectiveness of the proposed approach in solving the steady state of power system for a wide range of loading conditions. [ABSTRACT FROM AUTHOR]

Turbochargers are used predominantly in automotive vehicles to enhance the performance of these vehicles. Turbochargers comprises both centrifugal compressor and radial turbine. The radial turbine along with volute casing is chosen for this study to understand the flow characteristics. The radial turbine is investigated for varied operating conditions. The numerical study is carried out using ANSYS CFX. The pressure drop is influenced by both the mass flow rate and rotational speed of the turbine. The total-to-static efficiency at isentropic condition for varied operating conditions are compared and the total-to-static efficiency for case 3 is found be maximum as 62%. Hence, the case 3 operating parameters is found give the maximum total-to-static efficiency. [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]

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]

Fatigue strength of a material is one of the important mechanical properties to be known. In this study, the fatigue strength of S45C was predicted numerically. The main objective is to comprehend the most accurate technique for predicting the fatigue strength of S45C materials, while the specific aim is to estimate the fatigue strength of S45C numerically. Fatigue strength value resulted from the simulation was compared to that of theoretically S-N curve, DT indicating by completely rotating bending testing, NDT indicating by thermography techniques, carried out previously. Strain-based analysis was performed during simulation. Finally, it can be concluded that Fatigue-life resulted from the simulation is greater than that of DT experimental result. However, it is smaller than that of the theoretical S-N curve. Fatigue-limit or endurance limit resulted from the simulation is about 7.4 % lower than that generated by the theoretical S-N curve. Therefore, the simulation process is accurate enough to predict Fatigue-limit of S45C carbon steel material. [ABSTRACT FROM AUTHOR]

Road crashed barriers are invented to redirect errant vehicles safely upon collisions. Numerous studies have been done to improve its crashworthiness. In current research, the use of honeycomb panel is suggested as an additional shock absorber. The main objective of this research is to determine the best configuration of the newly proposed additional panel. ANSYS explicit software is utilized for simulations. Desired parameters; length of honeycomb panel (L0i), and thickness of honeycomb panel (H0i), are varied accordingly. The variations are based on a ratio of 1.0, 2.0, 3.0, 4.0 and 5.0. These parametric ratios are related to the ratio between the guardrail to the honeycomb panel. In this case, the guardrail has constant length and effective thickness of 2000 mm and 82.6 mm. Square-shaped cells of size 12.7 mm with thickness of 0.8 mm will be used. All configurations are tested through an impact simulation with an initial velocity of 60 km/h. Their respective displacement, velocity and acceleration will be collected to perform desired numerical analysis; Force (F), Specific Force (SF), Energy Absorption (EA), and Specific Energy Absorption (SEA). Different deformation mechanisms and equivalent (Von-Mises) stress distributions suggest its nature to resist the impact, prior to a failure. Some parameters and components are optimised to reduce computational burden. The use of additional rectangular honeycomb panel suggested more energy can be absorbed. Overall, it has been concluded that honeycomb's panel length of 1993.9 mm (parametric value of 1) and height of 82.60 mm offers the best configuration in having the best performance amongst all other configurations. [ABSTRACT FROM AUTHOR]

This study is devoted to analyse numerically the Saint-Venant equation. This equation is well known for solving water management problems as in assessment of water reserves using a Feed-forward network, and function management of the river system. All these phenomena are related to the unsteady flow of water in the system of rivers and canals, the flow of which is most often described by the hypothetical equation of Saint-Venant. One of the three-layer, feed-forward network framework, namely back-propagation network (BPN) is employed to represent the water resources management of Ugam river. The calculation is obtained for the motion of a river along the x-axis by using Python programming language. [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]