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The paper describes validation of a multidimensional semi-Lagrangian method with the use of a conservative fifth-order WENO scheme on the basis of computer simulation of models of rotating circular solid disks. Implementation of this method on GPU is briefly described. [ABSTRACT FROM AUTHOR]

The article presents an investigation of gas flow that occurs under typical for cold spraying conditions when supersonic gas jet, that exhausts from De Laval nozzle, and impinges on mask with a round perforation, behind that substrate is placed. Numerical simulation was made using software ANSYS Fluent. Shadowgraph was used to obtain images of gas flow. The results obtained were analyzed and compared. [ABSTRACT FROM AUTHOR]

In this paper, we study the dynamical properties of a discrete time prey predator model under imprecise biological parameters. We consider refuge for prey and cost of fear into prey reproduction. The equilibria of the model are obtained and the dynamic behaviors of the proposed system are examined. Hopf Bifurcation of the proposed prey predator model are analysis. Simulations of the model are performed for different parameters of the model. Numerical simulations show that the proposed discrete model exhibits rich dynamics of a chaotic and complex nature. [ABSTRACT FROM AUTHOR]

In this paper we study the Rayleigh-Taylor instability, attenuation of gravitational-capillary waves, the evolution of the dynamics of the interface between two media in the field of reciprocating horizontal linear vibrations at different grid sizes and at different boundary conditions. It is assumed that viscosities of both phases are equal. The numerical simulation of problems by the lattice Boltzmann equations (D2Q9) method is performed using the HCZ model. [ABSTRACT FROM AUTHOR]

The paper suggests using a helical coordinate system for numerical simulation of viscous flow in a channel with helical fins. A mathematical model was implemented in the package Comsol Multiphysics. The influence of four fins on the flow structure is analyzed. As a summary it is presented the dependency of darcy friction factor to Reynolds number for the pitch of screw fins S/D=3, 4, 5. [ABSTRACT FROM AUTHOR]

The aim of the paper is to present a regulation and control model of the two link manipulator end effector position. Attention is paid to kinematic and dynamic analysis of the manipulator. Then the simulation model with a control algorithm of its end effector position is proposed. MSC Adams Control Toolkit is used for computer simulation. Finally the results of the simulation are presented in graphical form. An example of a robot model that will be the objective of the solution in the paper consists of two members. The industrial robot can be considered as an open chain mechanism consisting of rigid links and joints. The movable arms are mounted on a solid base ensuring its stability in operation. A working tool, in our case a basket, is fixedly connected to the movable upper arm. Our aim is to describe the movement of the basket of the end member. The control of the position of the end member was performed by the MSC Adams program, which offers the possibility to build a control system and also the possibility of using regulator. In this case a proportional regulator with Kpgain is used. The stability of the basket is eliminated by the control circuit by applying a balancing torque that allows the basket to stabilize during movement. For the control system a feedback control circuit is provided. The regulator controlsthe equalization torque to keep the basket in a horizontal position during arm rotation. The aim was also to obtain results from the manipulation of the robot's end effector and to prove the ability and functionality of the designed balancing torque controller. The course of the current and desired angle while moving by trajectory is displayed graphically. [ABSTRACT FROM AUTHOR]

Present paper deals with numerical simulation of flow in simplified model of the axial turbine stage equipped with the hub-seal. Main subject of simulations is study of various geometrical modifications of the outlet-slot from the hub-seal. The purpose of these modifications is to suppress a negative effect of complex secondary structures on the stage efficiency. Secondary flow structures are formed as a result of interaction of main stream above the outlet-slot with the leakage-stream from the hub-seal. It was found that suitable shape of the outlet-slot can bring up to six tenth of percent in efficiency. [ABSTRACT FROM AUTHOR]

The paper presents the results of fatigue crack growth simulation of the transition joint for S235JR steel and A5083 aluminum with the Grade 1 titanium interlayer coat and A1050 aluminum. Calculations were performed using ANSYS software. The publication presents the crack growth phenomena observed during fatigue testing. Additionally, calculations of residual stresses distributions induced by the process of joining materials during welding were carried out. Results of crack length calculations were comparable with experimantal data. [ABSTRACT FROM AUTHOR]

The paper is focused on the study of supersonic gas flows with suspended particles past blunt bodies. Flows with particles of two different sizes are considered. The main feature of the issue under investigation is the significant difference of characteristic scales for carrying and dispersed phases. The study is based on a complex mathematical model of the two-phase flow. The model combines Eulerian description for the gas phase and Lagrangian description for the dispersed phase. The carrying phase dynamics is governed by modified Euler equations, taking into consideration the particle-gas interaction. To account for inter-particle collisions and interaction of particles with the body surface, direct numerical simulation is used. The results of mathematical modeling for a supersonic flow with binary particle admixture around a sphere are presented. The focus is on the analysis of the effects related to the influence of the interaction between particles of different size on the energy flux from the dispersed phase to the sphere surface. The results show that energy fluxes from the individual dispersed fractions to the body surface are nonlinear functions of the particle volume concentrations. Collisions between particles of different size give significant rise to the impact of smaller particles. At the same time, the total energy flux from the dispersed phase to the body surface changes almost linearly with the concentration of individual fractions. This allows using the results of monodispersed flow calculation for modeling of polydispersed flows. [ABSTRACT FROM AUTHOR]

In the paper, we theoretically studied the dynamics of mode II crack propagation in brittle solids with taking into account the finite duration of incubation of local fracture. The study was carried out by computer simulation using the movable cellular automaton method. We analyzed the influence of the magnitude of fracture incubation time on the fulfillment of the scale-invariance condition of dynamic crack propagation. We proposed a definition of this condition in terms of fracture incubation time and introduced a new physically based criterion to classify structural levels of fracture in brittle materials. [ABSTRACT FROM AUTHOR]

The paper presents the thermodynamic analysis for changing the fuel of an aviation gas turbine from kerosene to alternative gaseous fuels. Theoretical results are obtained using the CEA program and the numerical ones using a commercial CFD code. The gas turbine used for the application is a helicopter turboshaft for which the geometry of the combustor was carefully reproduced in a CAD environment. The paper details each necessary step to obtain the numerical results, as well as some comparison with experimental data. The conclusions are related to the similarities and the differences between the presented numerical results, considering the complexity of the entire gas turbine. A series of development perspectives are presented. [ABSTRACT FROM AUTHOR]

The convexity of reachable sets plays an essential role in the development of algorithms for solving optimal control problems and problems of feedback control. For nonlinear control systems the reachable sets are generally not convex and may have a rather complicated structure. However, for systems with integral quadratic constraints on the control B.Polyak showed that the reachable sets are convex if the linearization of the system is controllable and control inputs are restricted from above in L2 norm by a sufficiently small number. In the present paper we use this result to prove sufficient conditions for the convexity of reachable sets of a nonlinear control-affine system on small time intervals, assuming that control resources are limited by a given (not necessarily small) value. These conditions are based on the asymptotics for the minimal eigenvalue of the controllability Gramian of system linearization as a function of the length of the time interval. We prove the asymptotics for a linear time-invariant system containing a small parameter that implies the convexity of small-time reachable sets for some classes of two-dimensional nonlinear control systems. The results of numerical simulations for illustrative examples are discussed. [ABSTRACT FROM AUTHOR]

In this paper, a kinematic model of a mechanically couple platoon of two car-like vehicles is developed. Two different forms of the kinematic equations of motion are derived depending of the generalized coordinates used for the system description. The kinematic model is obtained in the form of a nonlinear driftless control system which is affine in the control inputs and can be employed for the design of different types of low-speed steering controllers for the following vehicle in the vehicle platoon. A linear feedback steering control for the following vehicle in the platoon is designed. Computer simulation tests using the derived kinematic equations of motion of the vehicle platoon along a curved path are carried out, in order to evaluate the validity of the developed kinematic model of the mechanically coupled car-like vehicle platoon and steering control. [ABSTRACT FROM AUTHOR]

The use of numerical simulations to obtain drag coefficient values cd for flow around a rough cylinder in the subcritical and critical Re number regions were the aim of this paper. The model of the cylinder with the trapezoidal waves on the surface was calculated. The results from simulations were compared with standard and available experimental results obtained by measuring of a rough cylinder with similar parameters of the relative roughness and flow regime. ANSYS Fluent software using the RANS SST k-ω turbulence model was chosen for the numerical simulations. This comparative study confirms the influence of the density and shape of protrusions on the value of the drag coefficient and thus on the shift of the position of the of cd drop to lower Re numbers. [ABSTRACT FROM AUTHOR]

In this paper, the filling process of micro-fluidic chip is simulated by Moldflow software. The volume shrinkage, cavitation, weld line and warpage deformation were studied. The simulation results show that the micro-fluidic chip can be completely filled and the surface molding quality can meet the application requirements. The numerical simulation results can predict the quality of injection molding micro-fluidic chip in actual production, and have important guiding significance for the optimization of process parameters and the design and modification of mold. [ABSTRACT FROM AUTHOR]

In this paper, the screw configuration of the intermeshing co-rotating twin-screw extruder for TPV is designed and numerically simulated. According to the mixing and conveying performance of conventional screw elements, kneading disc elements and toothed disc elements, four screw configurations in the mixing section of the extrusion system suitable for TPV mixing task are designed. The mixing process of materials in the channel under these four screw configurations is simulated by POLYFLOW software, and the results are analyzed to select the best screw configuration. [ABSTRACT FROM AUTHOR]

The trend towards the application of external thermal insulation composite systems (ETICS) on energy efficient façades under hot climatic conditions, is becoming increasingly important for energy saving in summer (summer heat protection). However, both the construction and the performance of the system should be investigated to ensure the functionality and the avoidance of damage. In this paper, the development and the functionality of ETICS as well as the analysis of measurement data for solving building-climatology challenging planning tasks in warm countries is presented. Related to the measurement data collected in a real case study, the results of a hydrothermal simulation tool are validated. Based on this, the use of thermal insulation under hot climatic conditions, for energy saving in summer, has been verified and the implementation into a simulation model is shown. For the verification of results, a case study in the campus of the American University in Ras al Khaimah (RAKRIC), in United Arab Emirates (UAE) was chosen, in which interior and exterior temperature and relative humidity values were measured. Even with the peculiarity of an irregular user behavior of the building, good accordance between measured and calculated values could be achieved. The optimized building design, facilitating a damage-free operation and a low building energy consumption, is presented in detail and essential optimization steps are discussed. Based on the analysis and evaluation of measurement data as well as the implementation of hygrothermal simulations, the presented study provides a guideline for planning of ETICS with respect to southern climate conditions. [ABSTRACT FROM AUTHOR]

The paper focuses on methods for dynamic analysis used in modern construction. The analysis of experimental data of the building, after action of seismic loading is used. Described technique enables the user to simulate behaviour of the structural system of a building based on the finite elements developed and implemented in LIRA-SAPR program. The technique allows solving dynamic problems taking into account physical nonlinearity. [ABSTRACT FROM AUTHOR]

This paper devotes to the numerical simulation of Van der Pol equation using fix and variable step size methods. The solution is obtained via two different methods of Runge-Kutta of order 5 (RK5) for fix step size and Runge-Kutta Fehlberg method (RKF) of order 5 for variable step size. The algorithms of fix and variable step size of RK5 and RKF methods, respectively are developed and coded in Matlab for model simulation. Local and global errors are computed for non-stiff and stiff problem of Van der Pol equation. RKF method using variable step size show low values of error for stiff problem with less number of iteration, hence indicate good performance of the method in approximating the solution of the Van der Pol model. [ABSTRACT FROM AUTHOR]

This paper discusses the design, simulation and construction of a two-wheeled self-balancing vehicle system. The model is designed with the help of Solid works 2018 computer modeling software, once the design calculations are perfect in all aspects. And structural analysis is carried out using Ansys R21. After the development of prototype, when the vehicle loses equilibrium on either side, spinning disc with hub motor attached in chassis acting as a gyroscope to provide counterbalance force (gyroscopic effect). This vehicle uses heavy mass rotor with higher inertia for better balancing. Two-wheeler has two wheels which acts as a gyro, it generates the necessary torque for self-balancing at greater speeds. But it creates a little amount of torque at slower speeds. The vehicle will be tested with zero precession velocity at first. The action of the handlebar must also be arrested. And the experiment involves balance at rest as well as at a slower speed. The vehicle's precession movement is stopped, and it moves in a straight path and test for balancing. As a result, to get a reactive gyroscopic torque, gyroscope was used for balancing. [ABSTRACT FROM AUTHOR]

The paper presents a study of the parameters of the angular stabilization circuit with relay actuators using MATLAB Simulink numerical simulation tools, which implements the principles of visually-oriented programming. This paper demonstrates the convenience of creating a model of a roll stabilization system in the MATLAB Simulink. This model is quite comprehensible and suitable for analysis, which not only simplifies the process of stabilization system synthesis but also allows performing the task with high efficiency. The roll stabilization system layout, presented as a relay system with all its advantages and disadvantages, is considered. During the analysis of such systems in MATLAB Simulink, it is possible to track the limit modes in such systems, determine the conditions for the self-oscillation occurrence, and assess the sliding mode quality. Advanced features of MATLAB Simulink allow not only to create a model and perform simulations but also to conduct large-format research aimed at improving both the structure of the stabilization system itself and the choice of its optimal parameters. [ABSTRACT FROM AUTHOR]

The article is devoted to the method of estimation of the effective mechanical properties of rocks by performing numerical calculations on the digital model of core. The digital model of core is constructed in the form of structured hexahedral grid based on CT scan data. In the representative volume element (RVE) of the core sample, a number of boundary value problems of the elasticity theory with various boundary conditions are solved. The pre-loading of the rock caused by pore pressure is also taken into account. The elasticity problems are solved numerically with the help of finite element method using CAE Fidesys. The results of the solution of each problem are averaged over the volume. Effective properties of core are estimated in the form of the generalized Hooke's law. The paper presents the results of calculations carried out at variable pressure for core made by one (sandstone) and several (pyrite, solid and solid calcite) minerals. It is shown that the dependence of the estimated elastic moduli on the pore pressure is linear. [ABSTRACT FROM AUTHOR]

This paper presents the geometric equations of motion for an aircraft in 3D space, and a series of numerical simulations have been performed, investigating the analysis of the TCAS system near an obstacle. This numerical simulation includes two distinct cases of interest; 1. when the obstacle is considered fixed (with the presentation of the situations in which there is a danger of a collision and in which there is no imminent danger) and 2. when the obstacle is considered mobile (another aircraft). A sphere with a radius of 5NM (nautical miles) has been created around the obstacle which represents the protection volume of the aircraft considered in the study. After the detailed analysis of the presented situations, the trajectory of the aircraft has been determined in case of bypassing the obstacle, as well as in the situation where there is an imminent danger of collision between the intruder aircraft and the aircraft considered as the target. [ABSTRACT FROM AUTHOR]

The paper presents a numerical homogenization of elastic properties of gyroid structures used in modern implantology. Gyroid structures can be characterized as a system of intersecting walls. Their numerical modeling and three-dimensional discretization by finite elements usually give a vast number of degrees of freedom. A homogenization approach based on a two-level method can be a practical solution. A coarse mesh discretizes the gyroid specimen at the macro-level, and elements are represented by homogenized properties taken from a representative volume element analysis at the meso-level. The application of the two-scale procedure is illustrated by a numerical simulation of compression tests of gyroid specimens. [ABSTRACT FROM AUTHOR]

The aim of this paper is to formulate a new concept of Discrete Element Method (DEM) dedicated to solid body mechanics. The new method is to be an answer to the disadvantages of the classic DEM, which are evident in computer simulations of small solid body objects but less important in the case of rock or powder mechanics. The creation of a computer code implementing the new algorithms is an integral part of the research. The paper presents the basic assumptions of the new method but omits implementation details. At the time of writing, the computer program has been in its pre-alpha phase and no results of computer simulations have been available. The proposed version of the method has been named DEM D+. [ABSTRACT FROM AUTHOR]

In Malaysia, an agency that is entrusted by the Government to perform mandatory vehicle inspection for public, commercial and private vehicles, receive many customers daily. Often complaints of problems received from the customers are associated with waiting time that leads to lost of business and dissatisfied customers. To address this issue, we propose a framework for modelling a vehicle inspection system using an integration of simulation and optimization approaches. The strengths of simulation and optimization are reviewed briefly that is hoped to reveal the synergy between the established methods in determining an appropriate customer's waiting time for inspection at a vehicle inspection centre. Relevant concepts and preliminary results are also presented and discussed in this paper. [ABSTRACT FROM AUTHOR]

In order to solve the problem that the satellite signal power is very weak and susceptible to interference, try to use the spatial filtering algorithm to produce a deeper null in the direction of the interference signal, so as to suppress the interference. In this paper, we will compare the least mean square (LMS), normalized LMS (NLMS) and Recursive least square (RLS) adaptive algorithms for spatial filtering. Finally, the content of the study will be verified by simulation. [ABSTRACT FROM AUTHOR]

In hardware-in-loop test of the aviation spectra camera, the liquid crystal light valve and digital micro-mirror device could not simulate the spectrum characteristics of the landmark. A test system frame was provided based on the color film for testing the spectra camera; and the spectrum characteristics of the color film was test in the paper. The result of the experiment shows that difference was existed between the landmark and the film spectrum curse. However, the spectrum curse peak should change according to the color, and the curse is similar with the standard color traps. So, if the quantity value of error between the landmark and the film was calibrated and the error could be compensated, the film could be utilized in the hardware-in-loop test for the aviation spectra camera. [ABSTRACT FROM AUTHOR]

The topology is always changing due to the high mobility of nodes in Delay Tolerant Networks (DTNs). On this base, it becomes a hot topic to propose an efficient routing algorithm in this area. According to the contact of region partition and the activity degree of the nodes, this paper puts forward a spray and wait routing algorithm based on region partition and node activity (RPANA). Through simulation, it can achieve higher message delivery rate than the other Spray and Wait (SAW) routing algorithms. In the meanwhile, it has less delay as well as overhead ratio. [ABSTRACT FROM AUTHOR]

In recently, traffic jams have become the focus and one used different approaches to study them. In this paper, the function of sin(x) is used to simulate the enter rate a of the peak period to work. The mean field approach has been used to calculate the phase diagrams and these results were compared with Monte Carlo simulations. They are good agreement. When traffic accidents occur at the exit, the exit rate β will be less than 1 and traffic jams will occur. Different fixed the exit rate β is used to calculate the additional energy consumption. The additional energy consumption will increase with the reducing of the exit rate β. [ABSTRACT FROM AUTHOR]

Localization of mobile station (MS) has now gained considerable attention due to its wide applications in military, environmental, health and commercial systems. Phrase angle and encode data of MSK system model are two critical parameters in time-of-arrival (TOA) localization technique; nevertheless, precise value of phrase angle and encode data are not easy to achieved in general. In order to meet the actual situation, we should consider the condition that phase angle and encode data is unknown. In this paper, a novel TOA localization method, which combine MUSIC algorithm and cross correlation algorithm in an appropriate interval, is proposed. Simulations show that the proposed method has better performance than music algorithm and cross correlation algorithm of the whole interval. [ABSTRACT FROM AUTHOR]

This paper introduces the Triple-section extraction process in the three-dimensional roadway layout of stagger arrangement method for longwall top-coal caving mining. This 3-D roadway layout of stagger arrangement method without coal pillars, which arranged the air intake roadway and air return roadway in different horizons, realizing the design theory transformation of roadway layout from 2D system to 3D system. And the paper makes systematic analysis to the geological, technical and economic factors, applies this new mining roadway layout technology for raising coal recovery ratio and solving the problems about full-seam mining in thick coal seam synthetically according to theoretical study and mining practice. Furthermore, the paper presents a physical simulation about inner staggered roadway layout of this particular longwall top-coal caving method. [ABSTRACT FROM AUTHOR]

This paper outlines the mathematical motion model of the research spacecraft that uses solar sail instead of an engine and a propellant. The mathematical motion model for solar sail spacecraft is formulated and described. The work considers the mathematical motion model within the heliocentric system of coordinates. The best way to assess the reasonableness of the mathematical model is the using model in motion simulation process. On the basis of the formulated mathematical model the special software complex for interplanetary transfer simulation is developed. Especially, the mission of the transfer of the spacecraft from the Earth's orbit to the potentially hazardous asteroid is simulated. The obtained results during simulation demonstrate correctness and feasibility of the considered mathematical motion model. [ABSTRACT FROM AUTHOR]

A flow structure around a ground vehicle has been studied by many researchers using numerous methods, either computational or experimental. However, no analysis of flow field generated by a car passing under a flyover has been carried out. One of the famous simplified models of a car is the Ahmed body that has been established to investigate the influence of the flow structure on the drag. In this paper, we investigate a flow field around Ahmed body of a single cruising condition as the vehicle passes under a flyover, using a computational method with RANS equation. The main objective of this paper is to evaluate the turbulence kinetic energy and velocity magnitude developed within the wall boundary created by the flyover, to the air flow field that is generated by the Ahmed reference car. It was observed that the simulated airflow passes the vehicle was bounded by the wall of the flyover and consequently changes the pattern of the flow field. Understanding the characteristic of this flow field under a flyover is essential if one wants to maximize the recovery of the dissipated energy which, for example, can be used to power a small vertical-axis wind turbine to produce and store electrical energy for lighting under the flyover. [ABSTRACT FROM AUTHOR]

This paper presents the numerical simulation of hot press forming process by introducing nanocoolant compared with chilled water into the cooling channel system of HPF tool. By using thermal analysis, the heat distribution between heated blank and tools are evaluated. The thermal analysis results show that the average enhancement of nanocoolant cooling rate is measured to be 30.2% higher compared with chilled water. The simulation data are validated with experimental hot press forming results. [ABSTRACT FROM AUTHOR]

Compared with common industrial coal gasification technology, solar CO2 coal gasification has the advantages of reducing CO2 emissions, high purity of product gas, which is also easy to be separated and be stored. One of the major problems affecting solar gasifier’ performance is the coal particle contaminating on the glass. So keeping the reactor quartz glass clean is the key to increase reactor efficiency and safety. CO2 replaces another std inert gas as sweep gas which is recyclable in solar CO2 coal gasification. This paper establishes a three dimensional mathematical model of a directly-irradiated cyclone-flow solar thermochemical reactor to investigate the effects of sweeping glass inlet positions, the transported pulverized coal particles inlet positions and different inlet flow velocity of the cleanliness of the quartz glass. The numerical results are validated by comparing with the experimental and numerical results of ETH 5 kW cyclone reactor. The results show that keeping the glass clean mainly depends on increasing the inlet flow velocity of the sweeping glass. Increasing the flow velocity can effectively reduce the coal particles contaminating the glass. However, there is an optimal flow velocity for avoiding coal depositing on the window glass. In the determined reactor structure, when the mass flow rate of the sweeping glass is 13.6%~18.2% of the total intake gas, the coal particle track is limited to the opening aperture area and the glass window can keep clean. [ABSTRACT FROM AUTHOR]

Certifying a transport airplane for the flights under icing conditions requires calculations aimed at definition of the dimensions and shapes of the ice formed on the airplane surfaces. Up to date, software developed in Russia for simulation of ice accretion and authorized by Russian certifying supervisory authority, is absent. The paper describes methodology IceVision recently developed in Russia for calculations of ice accretion on airplane surfaces. This methodology is implemented in CFD software FlowVision used by numerous companies and universities in Russia and abroad. The methodology differs from known approaches to simulation of ice accretion. In particular, changing the ice shape is calculated with use of technology VOF. This technology assumes calculations of continuous ice growth accompanied by local rebuilding the computational mesh. The implemented mathematical model provides capability to simulate formation of rime (dry) and glaze (wet) ice. Numerical solutions of validation test problems performed using methodology IceVision are demonstrated. [ABSTRACT FROM AUTHOR]

The guide frame is widely used in the installation of the pile foundation for the offshore wind power case. The guide frame can locate the position of offshore pile and retrieves the lateral deviation of pile in the piling process. In order to ensure the success of the pile installation, it is necessary to ensure the stability of the guide frame. This paper analyzed the stability of a guide frame based on an engineering case in Jiangsu province with numerical simulation method. [ABSTRACT FROM AUTHOR]

The paper presents the method for estimation wear value probability by the numerical simulation. The considered task is actual in many technical regions. The designed method is based on an analysis of the probability density of wear distribution as a function of mileage, which considered as stochastic variable. Using this proposition allow one to accurately predict the wear value and its dependence of using lubrication. The proposed method was applied to Sverdlovsk railroad data where the results shown that using of KLS lubricant allow to decrease the wear on 30-50% depending on the mileage value. [ABSTRACT FROM AUTHOR]

In this paper we present design process of a video based onboard system that needs to detect and avoid static obstacles by the members of a heterogeneous UAV formation. After motivating the importance and relevance of the research topic, we introduce the UAV platforms which will be used with the developed system. A saliency algorithm is used to address the problem object collision avoidance. Furthermore, we expose the demands needed for image stabilization to obtain a working algorithm. This relates directly with the UAV dynamics and with the performances of the gimbal that holds the video sensor. Finally, numerical simulations are performed to evaluate the suitability of the designed system for practical applications. [ABSTRACT FROM AUTHOR]

In this paper the problem of mutual interaction of incompressible viscous fluid flow with an elastic structure is considered. A model problem of aiflow induced vibratioon of a simplified human vocal folds model is studied. The main attention is paid to the problem of the periodical collisions of vocal folds. First, these collisions are taken into account in the flow model by the application of a suitable inlet boundary condition. Further, in the structure model the contact is resolved with the aid of application of Hertz forces. Numerical results are shown. [ABSTRACT FROM AUTHOR]

The mechanical properties of the polymeric samples were discussed in many papers. Only several of them investigates the mechanical properties of the 3D-printed sampled prepared by different technologies, i.e. FDM, FFF, MJM, SLA, SLS etc. More dense samples could be obtained by any art of SLA technology, for example, based on the DLP principles, whereby less dense samples made of any thermoplastic materials obtained by FFF technology. In the current paper the authors carried out, firstly, experiments and numerical simulation of the tensile and compression tests of the 3Dprinted samples made of ABS and PLA polymers. The initial CAD-model does not contained any topological information to the samples’ surface. Secondly, the same simulation runs but for CAD-model obtained by 3D-scanning were performed with respect to the surface appearance. The density of the material was taken as a goal function. And, thirdly, at the end the experimental and numerical results were compared. The deviation of the deformation forces between the numerical and experimental results for as-modelled in CAD and as-scanned samples was arranged within the 5 – 10% and strongly depended on the inner type of infill, represented by porosity coefficient. [ABSTRACT FROM AUTHOR]

This paper deals with the problem of calculation of Stress Intensity Factor in two ways: theoretically and numerically with two methods: Virtual Crack Closure Technique and J – Integral method. Three types of geometries were considered: plates with central/boundary crack and notch bending specimen. Numerical simulations covered a mesh sensitivity study for three mesh sizes and linear/nonlinear material model. Good correlation between exact solution and numerical tests was achieved. [ABSTRACT FROM AUTHOR]

This paper concentrates on selected aspects of numerical modeling of a short span thin-walled beams. The performed numerical simulations cover different types of finite elements (shell or solid finite elements) and different mesh sizes. Moreover the shape and magnitude of an initial geometrical imperfection is also investigated. The numerical analysis were made with the Newton-Raphson procedure with geometrical and material nonlinearity. The numerical results were compared with the laboratory four point bending test of a thin-walled beam. Furthermore, some guidelines for numerical simulations of a short span thin-walled beams in bending were proposed by authors. [ABSTRACT FROM AUTHOR]

The paper considers the possibility of using an actuator for controlling the flight of an anti-aircraft missile (AAM), in the form of a fast rotating rotor suspended on a joint in its body. Forced changes in the rotor (gyroscope) axis position angle in relation to the body axis of the AAM generate moments of forces that change the missile flight direction and guide it to a moving target. The mentioned system could be applied to combat low-flying and fast-moving targets. The analysis was only applied to motion in a vertical plane, and the selected digital simulation results were graphically presented. [ABSTRACT FROM AUTHOR]

Lattice QCD is one of the most powerful tools to analyze nonperturbative QCD phenomena. In lattice QCD, the space-time is discretized as a hypercubic lattice with the lattice spacing a. Numerical simulations of lattice QCD are the only tool to gain information on the hadron masses and scattering phases. In order to take physical quantity from dimensionless lattice quantity it is important to determine the scale parameter a. In this paper we use string tension K parameter to determine the physical scale of the theory. We have calculated the string tension parameter from planar Wilson loops, for 100 configurations, from lattice 84, 124, 164. Comparing these calculated values with that from the Regge slopes, K = (440 MeV)², we get the scale for each lattice. Finally, we can extrapolate in continuum limit to take the string tension parameter in QCD theory. [ABSTRACT FROM AUTHOR]

This paper deals with the simulation of UNS A92024 aluminium alloy cutting processes. In particular, 2D and 3D Finite Element Method (FEM) simulations were carried out in order to estimate cutting forces and chip morphology during turning operations. The material is modelled with two different set of parameters for the Johnson-Cook's (J-C) constitutive equation and a failure Cockroft and Latham's model exploited considers damage. The comparison between the predicted chip morphology and principal cutting forces at varying of J-C parameters and cutting regimes with those experimentally found are presented and discussed. The paper shows the importance of damage criterion in the cutting forces, during the simulation, especially in 3D. [ABSTRACT FROM AUTHOR]

The paper analyzes the dispersion of the mechanical parameters and its influence on the forming limit curves of sheet metals. The tests have been made for the case of the DC01 steel sheets. The dispersion of the mechanical parameters has been observed during the experimental research. On the basis of this dispersion, a forming limit band has been calculated using an alternate formulation of Hora's model (MMFC). [ABSTRACT FROM AUTHOR]

Computer simulation is widely used in the design and development of technical products. Multiscale nature of deformation and fracture of novel materials requires to use for this purpose not only the conventional finite element method but particle methods at different spatial scales as well. This paper presents a computer code aimed for discrete-continuum simulation of friction based on coupling finite elements (as a continuum method) with movable cellular automata (discrete particle method). Two computer codes based on finite elements and written in different programming languages are used: commercial and in-house. Peculiarities of the application program interfaces of the particle code for coupling with both finite element codes are described and analyzed. It is shown that the code developed takes the advantages of both cases and promises to be very efficient for simulating various contact problems including friction. [ABSTRACT FROM AUTHOR]

Various wireless, implantable and wearable devices are used for continuous monitoring of health condition. These devices consist of various type of biosensor such as pacemaker. The operational amplifier (op-amp) is an example of an extended device which is located at the front end of this biosensor. The op-amp plays an important role of amplifying the strength of a signal. This paper focuses on the development of a two stage CMOS op-amp in 0.13 μm technology using pseudo cascode compensation technique. The pseudo cascode compensation technology is proposed to enhance the stability of a circuit. The op-amp is implemented using 0.13 μm CMOS technology from Siltera (Malaysia) and is simulated using a Mentor Graphic Design Architect software package. The proposed op amp achieved DC gain of 57.87 dB, unity gain frequency of 57.390 kHz, bandwidth of 54.87 Hz and power dissipation of 3.02 mW for 50 μA external bias current. The op-amp shows exceptionally stable operation with phase margin of 80.65 ° and gain margin of 10.901 dB. [ABSTRACT FROM AUTHOR]