Journal articles: 'Diving- Computer simulation'

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Tomlinson, S. P., J. K. W. Lo, and D. G. Tilley. "Computer Simulation of Human Interaction with Underwater Breathing Equipment." Proceedings of the Institution of Mechanical Engineers, Part H: Journal of Engineering in Medicine 208, no. 4 (December 1994): 249–61. http://dx.doi.org/10.1243/pime_proc_1994_208_295_02.

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A mathematical model of the human respiratory system is being developed in order to simulate manned diving operations using various types of breathing equipment. A simulation study is presented of a human diving to a depth of 50 m, using a semi-closed re-breathing system with two different oxygen flow settings. A gas supply with 32.5 per cent oxygen concentration results in a safe dive whereas a 60 per cent setting indicates a dangerous diving condition. Typical respiratory model input data are illustrated for the lung, together with dimensional details for the re-breathing counterlung. The simulation results show variations in alveolar and pleural pressures, gas concentrations and partial pressures in the equipment and in the human respiratory system.

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Fitz-Clarke, John R. "Computer simulation of human breath-hold diving: cardiovascular adjustments." European Journal of Applied Physiology 100, no. 2 (February 24, 2007): 207–24. http://dx.doi.org/10.1007/s00421-007-0421-z.

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Hou, Zhi Hong. "Explore the Process of Computer Sports Simulation." Applied Mechanics and Materials 687-691 (November 2014): 1178–81. http://dx.doi.org/10.4028/www.scientific.net/amm.687-691.1178.

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Computer simulation in sport sports field has broad application prospects in recent years, has been successfully applied such as diving, gymnastics, trampoline, weightlifting and other sports items. This paper summarizes the research status by computer modeling, analysis of the characteristics and scope of several major modeling methods, to further explore the process of establishing sports computer simulation system.

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Yeadon, Maurice R., Pui W. Kong, and Mark A. King. "Parameter Determination for a Computer Simulation Model of a Diver and a Springboard." Journal of Applied Biomechanics 22, no. 3 (August 2006): 167–76. http://dx.doi.org/10.1123/jab.22.3.167.

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This study used kinematic data on springboard diving performances to estimate viscoelastic parameters of a planar model of a springboard and diver with wobbling masses in the trunk, thigh, and calf segments and spring dampers acting at the heel, ball, and toe of the foot segment. A subject-specific angle-driven eight-segment model was used with an optimization algorithm to determine viscoelastic parameter values by matching simulations to four diving performances. Using the parameters determined from the matching of a single dive in a simulation of another dive resulted in up to 31% difference between simulation and performance, indicating the danger of using too small a set of kinematic data. However, using four dives in a combined matching process to obtain a common set of parameters resulted in a mean difference of 8.6%. Because these four dives included very different rotational requirements, it is anticipated that the combined parameter set can be used with other dives from these two groups.

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Hou, Donglei. "Research on the Diving Simulation System on Three Dimensional Computer Animation." International Journal of Signal Processing, Image Processing and Pattern Recognition 9, no. 12 (December 31, 2016): 271–80. http://dx.doi.org/10.14257/ijsip.2016.9.12.26.

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Cai, Zheng Jie. "Review on Application of Virtual Reality in the Physical Simulation." Applied Mechanics and Materials 644-650 (September 2014): 3390–93. http://dx.doi.org/10.4028/www.scientific.net/amm.644-650.3390.

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VRT (Virtual Reality Technology) can simulate the real world dynamically by computer hardware and software to construct and experience artificia1 world.It can produce the dynamic environment to answer synchronically the gestures and language orders of users and make users and artificia1 world construct the synchrona1 and interactive relationship.In recent years,VRT has been used widely in the field of sports such as diving,gymnastics,trampoline,weightlifting,golf,basketball and skiing,especially at diving and trampoline.1. VRT (Virtual Reality Technology)

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Langbeheim, Elon, and Sharona T. Levy. "Diving into the particle model: Examining the affordances of a single user participatory simulation." Computers & Education 139 (October 2019): 65–80. http://dx.doi.org/10.1016/j.compedu.2019.05.006.

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Wells, Richard P., Patrick J. Bishop, and Malcolm Stephens. "Neck Loads during Head-First Collisions in Ice Hockey: Experimental and Simulation Results." International Journal of Sport Biomechanics 3, no. 4 (November 1987): 432–42. http://dx.doi.org/10.1123/ijsb.3.4.432.

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Spinal cord trauma due to head-first collisions is not uncommon in vehicle accidents, shallow water diving, football, or ice hockey. Two approaches to evaluating potential protective devices for ice hockey are described: an evaluative tool based upon an anthropometric test dummy, and a computer simulation of axial head-first collisions. Helmets reduced the peak cervical spine loads during low velocity head-first collisions by up to 8%. It is shown that large thicknesses of appropriate padding are necessary to hold the cervical spine loads to noninjurious levels. A head-first impact of 3.0 m • sec−1required padding deformations on the order of 94 mm to hold cervical spine loads below 2,000 N.

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Hou, Jiao Yi, Wei Feng Zou, Da Yong Ning, and Yong Jun Gong. "Numerical Simulation and Experimental Verification of Phase Change Buoyancy Control System." Applied Mechanics and Materials 906 (April 29, 2022): 59–66. http://dx.doi.org/10.4028/p-c90z80.

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Phase change buoyancy control systems (PBCS) driven by phase change materials have unique advantages over conventional hydraulically actuated buoyancy control systems, especially in their high adaptability for deep-sea exploration and seamless interaction with humans. Studying the heat transfer process and working mechanism of PBCS is helpful to research the precise control mode of the phase change buoyancy regulation system. In this study, we chose paraffin wax as the phase change material for PBCS. A buoyancy generator for phase change buoyancy regulation is designed and manufactured. By studying the relation between its expansion volume and heating time and heat input, the mathematical model of the volume change of PBCS is established. We obtain the calculation results of the PBCS working process by using the computer-aided software MATLAB. Experimental results show that the theoretical volume expansion velocity and volume expansion rate of paraffin are almost consistent with the experimental results. The mathematical calculation model is available and has a significant reference value for further research on the theoretical basis of the diving depth control of PBCS.

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Krasnodubets, L. A. "Multi-purpose information-measuring system for vertical profiling of the ocean environment." Monitoring systems of environment, no. 1 (March 25, 2021): 54–60. http://dx.doi.org/10.33075/2220-5861-2021-1-54-60.

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On the basis of a mathematical description of the processes of measuring the vertical profile of the density of the oceanic environment using a diving offshore autonomous probe – a profiler equipped with an onboard navigation system, a structure and a computer model of a multipurpose information-measuring system is proposed, which is intended for use in operational oceanology. The proposed system forms arrays of measurements of vertical profiles in situ of the density of seawater and its increment, as well as the speed of sound as functions of hydrostatic pressure, obtained during one sounding. At the same time, arrays of complete and thermohaline vertical stability of water layers, as well as the corresponding vertical distributions of the Väisälä-Brunt frequency of thermohaline oscillations in the stratified ocean environment, are formed almost in parallel. In the course of the simulation, an original model of the immersion of an autonomous marine probe in stratified sea water was used, as well as a dynamic model for measuring the trajectory parameters of its movement, taking into account the inertial properties of the acceleration and pressure sensors used. As an object of measurements, we used a simulation model of the ocean environment with vertical density stratification and the corresponding speed of sound in seawater, developed on the basis of real data of profile measurements obtained from specific hydrological stations. The verification of the models of the dynamic measurement processes was carried out by the method of computer simulation in the MATLAB & Simulink environment based on the comparison between the simulation results and available results from the hydrological stations. The illustrations of the results of computer simulation are presented.

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López Gutiérrez, Juan Roberto, Pedro Ponce, and Arturo Molina. "Real-Time Power Electronics Laboratory to Strengthen Distance Learning Engineering Education on Smart Grids and Microgrids." Future Internet 13, no. 9 (September 17, 2021): 237. http://dx.doi.org/10.3390/fi13090237.

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In the science and engineering fields of study, a hands-on learning experience is as crucial a part of the learning process for the student as the theoretical aspect of a given subject. With the COVID-19 pandemic in 2020, educational institutions were forced to migrate to digital platforms to ensure the continuity of the imparted lectures. The online approach can be challenging for engineering programs, especially in courses that employ practical laboratory methods as the primary teaching strategies. Laboratory courses that include specialized hardware and software cannot migrate to a virtual environment without compromising the advantages that a hands-on method provides to the engineering student. This work assesses different approaches in the virtualization process of a laboratory facility, diving these into key factors such as required communication infrastructure and available technologies; it opens a discussion on the trends and possible obstacles in the virtualization of a Real-Time (RT) laboratory intended for Microgrid education in a power electronics laboratory course, exposing the main simulation strategies that can be used in an RT environment and how these have different effects on the learning process of student, as well as addressing the main competencies an engineering student can strengthen through interaction with RT simulation technologies.

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Dukkipati, R. V., S. S. Vallurupalli, and M. O. M. Osman. "DISCRETE TIME ADAPTIVE ACTIVE SUSPENSION FOR A HALF-CAR MODEL." Transactions of the Canadian Society for Mechanical Engineering 21, no. 3 (September 1997): 221–72. http://dx.doi.org/10.1139/tcsme-1997-0012.

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This paper presents a discrete time adaptive active suspension for a multi-degree of freedom (MDOF) half-car model. The study involves formulation of a pitch plane half-car model involving four degrees of freedom and various nonlinear time varying (NTV) parameters. A multi-degree of freedom skyhook reference model has been described in this paper. Discrete auto regressive moving average (DARMA) models for the NTV-MDOF and the reference model have been developed. A modified version of the least squares estimation in which the controller parameters are updated as a matrix rather than as a vector has been derived in this paper. This approach reduces the computational time required for an adaptive controller parameters estimation and enhances the hardware implementation process. Computer simulation results indicate good adaptation to the reference model and maintenance of static equilibrium conditions for large squat and nose diving longitudinal manoeuvres. The responses also indicate an optimal vibration isolation and suspension travel performance by adapting to the reference model.

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Yang, Xiao, Ding Tian, Qiaorui Si, Minquan Liao, Jiawei He, Xiaoke He, and Zhonghai Liu. "Flow Loss Analysis and Optimal Design of a Diving Tubular Pump." Machines 10, no. 3 (February 25, 2022): 175. http://dx.doi.org/10.3390/machines10030175.

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As important parts of underground water conveyance equipment, diving tubular pumps are widely used in various fields related to the national economy. Research and development of submersible pumps with better performance have become green goals that need to be achieved urgently in low-carbon development. This paper provides an effective approach for the enhancement of the performance of a diving tubular pump by adopting computational fluid dynamics, one-dimensional theory, and response surface methodology. First, the flow loss characteristics of the pump under several flow rate conditions are analyzed by entropy production theory, and then the impeller and guide vanes are redesigned using the traditional one-dimensional theory. Then, the surface response experimental method is used to improve pump hydraulic efficiency. The streamline angle (A) of the front cover of the impeller blade, the placement angle (B) of the middle streamline inlet, and the placement angle (C) of the rear cover flowline inlet are the response variables to optimize the design parameters of the diving tubular pump. Results show that wall entropy production and turbulent kinetic energy entropy production play the leading role in the internal flow loss of the diving tubular pump, while viscous entropy production can be ignored. The flow loss inside the impeller is mainly concentrated at the inlet and the outlet of the impeller blade, and the flow loss inside the guide vane is mainly concentrated in the area near the guide vane and the entrance of the guide vane. A, B, and C are all significant factors that affect efficiency. The order of the influencing factors from strong to weak is as follows: A2 (p = 0.000) > C (p = 0.007) = A × B (p = 0.007) > B (p = 0.023) > B2 (p = 0.066) > A × C (p = 0.094) > A (p = 0.162) > C2 (p = 0.386) > A × B (p = 0.421). The best combination of response variables after surface response test design is A = 9°, B = 31°, and C = 36°. After optimization, the pump efficiency and the head of the model pump are increased by 32.99% and 18.71%, respectively, under the design flow rate. The optimized model pump is subjected to tests, and the test data and the simulation data are in good agreement, which proves the feasibility of using the surface response method to optimize the design of the model pump.

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Cohen, Raymond C. Z., Simon M. Harrison, and Paul W. Cleary. "Dive Mechanic: Bringing 3D virtual experimentation using biomechanical modelling to elite level diving with the Workspace workflow engine." Mathematics and Computers in Simulation 175 (September 2020): 202–17. http://dx.doi.org/10.1016/j.matcom.2020.03.007.

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Bangzhen Huang, Bangzhen Huang, Yani Cui Bangzhen Huang, Jia Ren Yani Cui, and Jiafu Yi Jia Ren. "Miniature Detection Buoy Based on Fuzzy Adaptive PID Algorithm." 電腦學刊 33, no. 6 (December 2022): 119–29. http://dx.doi.org/10.53106/199115992022123306010.

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The ocean buoy is an important technical means to obtain ocean environmental parameters as a newly developed detection technology. Traditional ocean buoys use hydraulic devices to change the volume of the oil bladder to achieve fixed-depth control, with slow response speed and long detection cycle. Therefore, it can only be applied to deep-sea environment and lacks the ability of rapid and fine detection in shallow waters (<200m). Considering the above problems, the paper designs a miniature detection buoy, which adopts an innovative inner and outer sleeves design. The miniature detection buoy uses a geared motor to drive the internal screw rotation to quickly stretch and shrink the volume of the shell to achieve the functions of floating, diving and fixed-depth. Moreover, the control performance research is carried out by establishing the dynamics model of the miniature detection buoy. According to the model, the fuzzy adaptive PID control algorithm is used to accurately control the speed and steering of the geared motor. The simulation results show that the buoy system with the fuzzy adaptive PID control algorithm has better fixed-depth accuracy and response speed than the classic PID control algorithm.

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Van Den Eeckhout, M., M. Vanhoucke, and B. Maenhout. "A column generation-based diving heuristic to solve the multi-project personnel staffing problem with calendar constraints and resource sharing." Computers & Operations Research 128 (April 2021): 105163. http://dx.doi.org/10.1016/j.cor.2020.105163.

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Huang, Jiafeng, Hyeung-Sik Choi, Dong-Wook Jung, Ki-Beom Choo, Hyunjoon Cho, Phan Huy Nam Anh, Ruochen Zhang, Joon-Young Kim, Daehyeong Ji, and Jung-Hyeun Park. "Analysis of a New Twin Hybrid Autonomous Underwater Vehicle." Applied Sciences 13, no. 3 (January 25, 2023): 1551. http://dx.doi.org/10.3390/app13031551.

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The twin hybrid autonomous underwater vehicle (THAUV) is a novel type of unmanned underwater platform that consists of a twin torpedo-shaped hull and is actuated by two buoyancy engines and two thrusters proposed in this paper. The THAUV was designed to have faster speed generated by the two buoyancy engines and two thrusters. The two buoyancy engines on each hull and the airfoil are mainly responsible for the diving and surfacing motion, and the thrusters drive the THAUV along the horizontal plane. The THAUV is capable of carrying more instrumentation and energy than a conventional hybrid autonomous underwater vehicle (HAUV) with a single buoyancy engine such that the THAUV can perform more exploration tasks and operate for a longer period in a one-time operation. Different from other unmanned underwater vehicles (UUVs) with two airfoils or wings, the THAUV has a single airfoil connecting the twin hull such that it does not require connecting bars and additional airfoils. For this reason, the structure of THAUV is more compact and simpler. In this paper, a new compact THAUV is designed and CFD simulation is used to obtain the hydrodynamic parameters of THAUV operation in water. The motion model of the THAUV is also established and the operating parameters of the THAUV are obtained by simulation.

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T., Stanciu. "Control of metabolic gases in hyperbaric chambers." Scientific Bulletin of Naval Academy XXII, no. 2 (December 15, 2019): 61–68. http://dx.doi.org/10.21279/1454-864x-19-i2-007.

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Respiratory effort in hyperbaric conditions is increased, leading to an increase in the diver's respiratory flow, increased oxygen consumption, and consistent carbon dioxide production. The knowledge of these physical and physiological phenomena involved during the hyperbaric respiration was studied theoretically in collaboration with the "Ovidius" University of Constanta, Faculty of Medicine. They were verified by experimental determinations on groups of divers in the Diving Center hyperbaric complex.

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T, Stanciu. "Aspects regarding the maintenance of climate inside the hyperbaric chamber of the Diving Center." Scientific Bulletin of Naval Academy XIX, no. 1 (July 15, 2018): 77–84. http://dx.doi.org/10.21279/1454-864x-18-i1-011.

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The climate conditioning of a hyperbaric chamber is extremely important, as the health or even lives of the divers depend on it. Climate conditioning consists of controlling and maintaining the following factors inside the enclosure:  Temperature  Humidity  The parameters of the breathing gas In this paper I have analyzed some of the aspects regarding the thermo-hygrometric phenomena and the composition of the breathing gas mix, phenomena that accompany any dive in saturation. The variation in temperature and humidity under pressure and during decompression differs from the unitary dives with Nitrox, because of helium, the main component of breathing gas. When planning the dive, one must take into account the presence of atmospheric air in the hyperbaric chamber at the beginning of the compression process, in order to avoid hyperoxia.

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Yang, Kaibiao, Wenhan Dong, Ming Cai, Shengde Jia, and Ri Liu. "UCAV Air Combat Maneuver Decisions Based on a Proximal Policy Optimization Algorithm with Situation Reward Shaping." Electronics 11, no. 16 (August 19, 2022): 2602. http://dx.doi.org/10.3390/electronics11162602.

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Autonomous maneuver decision by an unmanned combat air vehicle (UCAV) is a critical part of air combat that requires both flight safety and tactical maneuvering. In this paper, an unmanned combat air vehicle air combat maneuver decision method based on a proximal policy optimization algorithm (PPO) is proposed. Firstly, a motion model of the unmanned combat air vehicle and a situation assessment model of air combat was established to describe the motion situation of the unmanned combat air vehicle. An enemy maneuver policy based on a situation assessment with a greedy algorithm was also proposed for air combat confrontation, which aimed to verify the performance of the proximal policy optimization algorithm. Then, an action space based on a basic maneuver library and a state observation space of the proximal policy optimization algorithm were constructed, and a reward function with situation reward shaping was designed for accelerating the convergence rate. Finally, a simulation of air combat confrontation was carried out, which showed that the agent using the proximal policy optimization algorithm learned to combine a series of basic maneuvers, such as diving, climb and circling, into tactical maneuvers and eventually defeated the enemy. The winning rate of the proximal policy optimization algorithm reached 62%, and the corresponding losing rate was only 11%.

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Wang, Joseph, Yong Cao, Raed Kafafy, and Viktor Decyk. "Electric Propulsion Plume Simulations Using Parallel Computer." Scientific Programming 15, no. 2 (2007): 83–94. http://dx.doi.org/10.1155/2007/272431.

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A parallel, three-dimensional electrostatic PIC code is developed for large-scale electric propulsion simulations using parallel supercomputers. This code uses a newly developed immersed-finite-element particle-in-cell (IFE-PIC) algorithm designed to handle complex boundary conditions accurately while maintaining the computational speed of the standard PIC code. Domain decomposition is used in both field solve and particle push to divide the computation among processors. Two simulations studies are presented to demonstrate the capability of the code. The first is a full particle simulation of near-thruster plume using real ion to electron mass ratio. The second is a high-resolution simulation of multiple ion thruster plume interactions for a realistic spacecraft using a domain enclosing the entire solar array panel. Performance benchmarks show that the IFE-PIC achieves a high parallel efficiency of ≥ 90%

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Zhang, Fengrui, Jiaoyi Hou, Dayong Ning, and Yongjun Gong. "Depth Control of an Oil Bladder Type Deep-Sea AUV Based on Fuzzy Adaptive Linear Active Disturbance Rejection Control." Machines 10, no. 3 (February 22, 2022): 163. http://dx.doi.org/10.3390/machines10030163.

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The deep-sea autonomous underwater vehicle (AUV) is equipment of vital importance for ocean exploration, monitoring, and surveying. With a variable buoyancy system (VBS), AUV can achieve rising, diving, and hovering in the water column. This paper proposes a deep-sea AUV with an oil bladder type hydraulic VBS, which controls the oil flow rate with a proportional valve. However, the implementation of accurate depth control for AUV faces various challenges due to the varying water density with depth, the non-linear feature of the hydraulic system, and the disturbance from sea flows and currents. To tackle these problems, a third-order linear active disturbance rejection controller (LADRC) and its fuzzy adaptive version were designed and implemented in MATLAB/Simulink based on the state-space function of the proposed AUV system. Compared with the conventional PID controller, the simulation results indicate that the proposed LADRC controller shows strong robustness to disturbance, with other advantages including smaller steady-state error, overshoot, settling time, and response time. Moreover, the proposed fuzzy LADRC controller could further decrease the overshoot caused by the increasing target distance. The results prove that the designed depth controllers can meet the control requirements of the proposed deep-sea AUV.

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Оrdabayeva G.К., Dzhusupbekova G.T., and Rakhymbek N. "DESIGN AND SIMULATION OF VIRTUAL LOCAL AREA NETWORK USING CISCO PACKET TRACER." BULLETIN 6, no. 388 (December 15, 2020): 6–14. http://dx.doi.org/10.32014/2020.2518-1467.176.

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Modern local networks consist of several subscriber devices located inside the same building. Computers on the local network are interconnected using network equipment - switches. By default, all devices connected to the ports of the same switch can communicate by exchanging network packets. Computer networks of data transmission are the result of the information revolution and in the future will be able to form the main means of communication. The worldwide trend towards the integration of computers in the network is due to a number of important reasons, such as the acceleration of the transmission of information messages, the ability to quickly exchange information between users, receiving and transmitting messages (faxes, E-mail letters, electronic conferences, etc.) without leaving the workplace, the ability to instantly receive any information from anywhere in the world, as well as the exchange of information between computers of different manufacturers working under different software. A large number of broadcast packets sent by devices leads to a decrease in network performance, because instead of useful operations, the switches are busy processing data addressed to everyone at once. The situation forces us to divide such large networks into autonomous subnets; as a result, the logical structures of the network are different from the physical topologies. This article discusses VLAN technology (Virtual Local Area Network - VLAN), which allows you to divide one local network into separate segments.

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JACOB, ELIZABETH, M. MANOJ, and ROSCHEN SASIKUMAR. "VOLUME SEGMENTATION BY POST-PROCESSING DATA FROM SIMULATION OF SOLIDIFICATION IN THE METAL CASTING PROCESS." International Journal of Modeling, Simulation, and Scientific Computing 04, supp01 (August 2013): 1341005. http://dx.doi.org/10.1142/s1793962313410055.

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In the process of interpreting simulation results, new post-processing techniques are developed. This work presents a post-processing method that analyzes the solidification pattern formed by simulation of the solidification process of molten metal in a mold to produce shaped castings. Simulations generally involve numerical solutions of differential equations which are discretized by dividing the three-dimensional computational domain into small finite volume elements using a 3D grid. The locations of the grid points and values of the solidification time at these locations are used to divide the spatial data into 3D sections such that starting from a hotspot location within the section that has high solidification time, there is a gradient outwards with lower values of solidification time. Each section is assumed to be fed by one or more feeders that must freeze only after the section has solidified completely. The volume of a feeder can be determined from the volume of the section it is supposed to feed. The volume and surface area of sections are determined approximately to calculate feeder size and dimensions. The post-processing algorithm is a simulation-based quantitative approach to feeder design which in conventional foundry practice has been more of an art than science. It is also general enough for use in other 3D segmentation applications.

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Malakar, Preeti, Thomas George, Sameer Kumar, Rashmi Mittal, Vijay Natarajan, Yogish Sabharwal, Vaibhav Saxena, and Sathish S. Vadhiyar. "A Divide and Conquer Strategy for Scaling Weather Simulations with Multiple Regions of Interest." Scientific Programming 21, no. 3-4 (2013): 93–107. http://dx.doi.org/10.1155/2013/682356.

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Accurate and timely prediction of weather phenomena, such as hurricanes and flash floods, require high-fidelity compute intensive simulations of multiple finer regions of interest within a coarse simulation domain. Current weather applications execute these nested simulations sequentially using all the available processors, which is sub-optimal due to their sub-linear scalability. In this work, we present a strategy for parallel execution of multiple nested domain simulations based on partitioning the 2-D processor grid into disjoint rectangular regions associated with each domain. We propose a novel combination of performance prediction, processor allocation methods and topology-aware mapping of the regions on torus interconnects. Experiments on IBM Blue Gene systems using WRF show that the proposed strategies result in performance improvement of up to 33% with topology-oblivious mapping and up to additional 7% with topology-aware mapping over the default sequential strategy.

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Bryja, Danuta, and Adam Popiołek. "Vibrations of the overhead catenary caused by the passage of a high-speed train through the track stiffness discontinuity." Transportation Overview - Przeglad Komunikacyjny 2018, no. 6 (June 1, 2018): 21–31. http://dx.doi.org/10.35117/a_eng_18_06_03.

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The paper presents the methodology for simulating vibrations of the railway catenary, caused by the passage of the train through the track stiffness discontinuity. The concept of the simulation algorithm takes into account the dynamic interaction between pantographs and the overhead contact wire as well as nonlinearity resulting from the specificity of the droppers behaviour, which do not carry compression - they only carry tensile forces. The coupling of track and rail vehicles vibrations is also included. According to physics, the effect of vibrations of the catenary carried by pantographs on the railway vehicle was not taken into account, which allowed to divide the simulation algorithm into two stages and develop two computer programs with a defined hierarchy of operation. In the first stage of the simulation, the time-histories of vibrations and vibration velocities of those train cars, on which the pantographs are mounted, are calculated. In the second stage, the previously calculated time-histories are set as the input data and the vibration characteristics of the catenary and contact force between pantograph and the contact wire are calculated. The paper presents examples of vibration simulations of a rail vehicle observed in real time at the theoretical point of the pantograph base. The results of the second stage of the simulation were also shown: selected vibration time-histories of the pantograph and the five-span section of the catenary, and oscillations of the contact force between pantograph and the contact wire. The impact of the track stiffness discontinuity on catenary vibration was assessed.

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Hao, Zhoushao. "Naive Bayesian Prediction of Japanese Annotated Corpus for Textual Semantic Word Formation Classification." Mathematical Problems in Engineering 2022 (March 16, 2022): 1–14. http://dx.doi.org/10.1155/2022/8048335.

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With the rapid development of Japanese information processing technology, problems such as polysemy and ambiguity at the text and dialogue level, as well as unregistered words, have become increasingly prominent because computers cannot fully “understand” the semantics of words. How to make the computer “understand” the semantics of words accurately requires the computer to “understand” the rules of converting and integrating words into words from the perspective of semantics. Traditional Japanese text classification mostly adopts the text representation method of vector space model, which has the problem of confusing classification effect. Therefore, this paper proposes the topic of constructing a semantic word formation pattern prediction model based on a large-scale annotated corpus. This paper proposes a solution that combines Japanese semantic word formation rules with pattern recognition algorithms. Aiming at this scheme, a variety of pattern recognition algorithms were compared and analyzed, and the naive Bayesian model was decided to predict semantic word formation patterns. This paper further improves the accuracy of computer prediction of Japanese semantic word formation patterns by adding part of speech. Before modeling, the parts of speech of words are automatically tagged and manually checked based on the original annotated corpus. In the research on predicting Japanese semantic word formation patterns, this paper builds a semantic word formation pattern prediction model based on Naive Bayes and conducts simulation experiments. We divide the eight types of semantic word formation patterns in the annotated corpus into two groups, and divide the obtained sample sets into training sets and test sets, so that the Naive Bayes model first learns semantic word formation rules based on the training sets of each group. Semantic word formation patterns are predicted on the test set for each group. The simulation results show that the prediction model of semantic word formation mode has a generally high degree of fit and prediction accuracy. The prediction model of semantic word formation pattern based on this theory can ensure that the computer can judge the semantic word formation pattern more accurately.

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Xiaokaiti, Aizimaiti, Yurong Qian, and Jia Wu. "Efficient Data Transmission for Community Detection Algorithm Based on Node Similarity in Opportunistic Social Networks." Complexity 2021 (May 28, 2021): 1–18. http://dx.doi.org/10.1155/2021/9928771.

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With the rapid development of 5G era, the number of messages on the network has increased sharply. The traditional opportunistic networks algorithm has some shortcomings in processing data. Most traditional algorithms divide the nodes into communities and then perform data transmission according to the divided communities. However, these algorithms do not consider enough nodes’ characteristics in the communities’ division, and two positively related nodes may divide into different communities. Therefore, how to accurately divide the community is still a challenging issue. We propose an efficient data transmission strategy for community detection (EDCD) algorithm. When dividing communities, we use mobile edge computing to combine network topology attributes with social attributes. When forwarding the message, we select optimal relay node as transmission according to the coefficients of channels. In the simulation experiment, we analyze the efficiency of the algorithm in four different real datasets. The results show that the algorithm has good performance in terms of delivery ratio and routing overhead.

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Grechnikov, Fedor Vasilievich, Alexander Evgenievich Afanasyev, Vladimir Rodionovich Kargin, and Boris Vladimirovich Kargin. "Pressing Tubes with Conical-Stepped Needles Computer Simulating." Key Engineering Materials 684 (February 2016): 204–10. http://dx.doi.org/10.4028/www.scientific.net/kem.684.204.

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There are the results of computer simulating using DEFORM-2D specialized software and experimental researches during the pressing of aluminium alloys tubes with conical-stepped needles. On the basis of the experiment mathematical planning and dividing coordinate grid the influence of the taper angle and needle position to the pressing stress and the intensity of deformation relative to the die parallel land was established. The optimal parameters determining methods of conical-stepped needles geometry were proposed.

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Agusri, Erny, Muhammad Arfan, and Muhammad Arfan. "Analysis of traffic density onthree-way junction in Jalan Sukabangun 2 using Vissim simulations model." International Journal of Engineering & Technology 10, no. 2 (June 11, 2021): 124. http://dx.doi.org/10.14419/ijet.v10i2.31573.

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VISSIM is a Simulations model which means a city traffic simulation model. VISSIM is a simulation software used by professionals to create simulations from dynamic traffic scenarios before making real plans. This research was conducted to determine how traffic performance and traffic performance optimization at the junctions between the existing conditions and the Vissim program caused by congestion. An effective method for overcoming non-jammed junctions can be made using the VISSIM method. This study was conducted at THREE-WAY JUNCTION in Jl. Sukabangun 2 (South) - Jl. R.A Abusamah (West) - Jl. Sukabangun 2 (Utara) - Jl. BeringinSukabangun 2 (East). In this study, three variations were used, namely the traffic light method, the method of forbidden turning right, and the method of dividing the road and turning signs. The results of PTV Vissim simulation showed that the traffic light method has a quite high queue length, namely 79m compared to the existing condition of 63m, for the vehicle delay in this method is 98.954s. On the method of forbidden turning right from the direction of Jl. BeringinSukabangun 2 (East) has a low queue length of 0.287m compared to the existing condition of 63m. The vehicle delay in this method is 13.307s. The method of dividing the road and turning signs, the queue length is quite low at 1.147m compared to the existing condition of 63m. The vehicle delay in this method is 30,169s. The results of the simulation revealed that the most effective method at THREE-WAY JUNCTION in jalanSukabangun 2 is method of forbidden turning right, dividing the roads and turning signs.

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Solomonov, K. N. "Application of CAD/CAM Systems for Computer Simulation of Metal Forming Processes." Materials Science Forum 704-705 (December 2011): 434–39. http://dx.doi.org/10.4028/www.scientific.net/msf.704-705.434.

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It is shown that application of graphic techniques and CAD/CAM systems for solving problems of metal forming makes it possible to obtain satisfactory results. Using well known COMPAS graphical system, it is possible to plot diagrams of contact pressures for some special cases. PARSHTAMP software developed by authors enables to calculate boundary dividing lines of metal flow during deformation of flat preforms.

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Ognev, Igor I., Anton P. Zyryanov, Maksim V. Pyataev, and Aleksandr A. Gulyarenko. "Influence of parameters of a pneumatic grain seeder distributor on the uniform distribution of seeds." E3S Web of Conferences 193 (2020): 01031. http://dx.doi.org/10.1051/e3sconf/202019301031.

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The article considers the issue of substantiating the distributing working body parameters for a pneumatic grain seeder. Work on the subject matter is mainly experimental in nature and not sufficiently deeply worked out theoretically. Based on computer simulation, the article determines the most preferred layout of the distributor dividing head, establishes a rational form of the reference cone and the location of the outlet pipes. Based on the simulation of the movement of seed grain particles, the individual design parameters of the distributor dividing head are specified. The results of experimental studies are presented confirming the theoretical background.

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Zhang, Y. R., L. Gao, S. J. Li, and H. X. Bi. "Thermal Analysis of Dedicated Computer Based on ANSYS." Materials Science Forum 697-698 (September 2011): 277–81. http://dx.doi.org/10.4028/www.scientific.net/msf.697-698.277.

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After creating the three-dimensional models of dedicated computer, models can be smoothly put into ANSYS through interface between Pro/E and ANSYS. By selecting the grid cells, setting parameters of material properties, dividing grids, applying load and boundary conditions and post-processing, the temperature contours of the whole case and its key components are got. Compared with the test results, it was verified that the feasibility and rationality of carrying out thermal simulation by ANSYS software, providing a theoretical basis for the designers to optimize dedicated computer case.

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Dmitriev, Boris A., Filip V. Toukach, Klaus-Jürgen Schaper, Otto Holst, Ernst T. Rietschel, and Stefan Ehlers. "Tertiary Structure of Bacterial Murein: the Scaffold Model." Journal of Bacteriology 185, no. 11 (June 1, 2003): 3458–68. http://dx.doi.org/10.1128/jb.185.11.3458-3468.2003.

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ABSTRACT Although the chemical structure and physical properties of peptidoglycan have been elucidated for some time, the precise three-dimensional organization of murein has remained elusive. Earlier published computer simulations of the bacterial murein architecture modeled peptidoglycan strands in either a regular (D. Pink, J. Moeller, B. Quinn, M. Jericho, and T. Beveridge, J. Bacteriol. 182: 5925-5930, 2000) or an irregular (A. Koch, J. Theor. Biol. 204: 533-541, 2000) parallel orientation with respect to the plasma membrane. However, after integrating published experimental data on glycan chain length distribution and the degree of peptide side chain cross-linking into this computer simulation, we now report that the proposed planar network of murein appears largely dysfunctional. In contrast, a scaffold model of murein architecture, which assumes that glycan strands extend perpendicularly to the plasma membrane, was found to accommodate published experimental evidence and yield a viable stress-bearing matrix. Moreover, this model is in accordance with the well-established principle of murein assembly in vivo, i.e., sequential attachment of strands to the preexisting structure. For the first time, the phenomenon of division plane alternation in dividing bacteria can be reconciled with a computer model of the molecular architecture of murein.

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Wang, Yong. "Communication Principle of Literature Database Based on Spatial and Temporal Segmentation Technology." Applied Mechanics and Materials 543-547 (March 2014): 2418–21. http://dx.doi.org/10.4028/www.scientific.net/amm.543-547.2418.

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In this paper we introduce cross tree and block mathematical principles into the design of database system, divide the time sequence and storage space of computer database system, establish the mathematical model and algorithm of computer resources database system, and design the test database system. In this paper, we use high performance interface of Display Port, by way of coupling to communicate on two port control, and use RHEL 6.2 Linux virtual machine to do simulation experiment on process of database system. Through the simulation we find the API which is called by Read, Close, Mmap, Stat, Fstat is similar. It is consistent with the actual situation, and verifies the reliability of the program. Finally, we apply the database system to the network database construction of sports literature resources in the new town of Poyang Lake area. It reaches the effect that sport resources are shared by all. It provides technical support for the application of computer database system.

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Sun, Yong, Li Zhao, Neng Xu, and Rong Ou. "Research of Visual Stimulation Method and Design of Visual Stimulator Based on Brain-Computer Interface." Applied Mechanics and Materials 734 (February 2015): 375–82. http://dx.doi.org/10.4028/www.scientific.net/amm.734.375.

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Brain Computer Interface (BCI) is a new ways of communicating with outside for the loss of some or all of the muscles controlling function of the patients. And the BCI is to set up a new information communication and control channel though the computer or other electronic device between the human brain and the external environment that does not depend on the peripheral nerve and muscle tissue. Firstly, this paper studies the methods of visual stimulation based on Brain Computer Interface that classified by stimulating form can be divided into flash simulation and figures simulation and classified by stimulating frequency can be divide into transient visual stimulation and steady-state visual stimulation. Then, using FPGA and the VGA interface designed of the visual stimulator that can be used to acquisition of steady-state visual evoked potential. Finally, adopting EEG signal processing platform verify this simulator. After numbers of verification, this simulator obtains a good desired result which achieved over 80% accuracy rate.

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Dobrovolskij, Dascha, and Katja Schladitz. "Simulation of Ultrasonic Backscattering in Polycrystalline Microstructures." Acoustics 4, no. 1 (February 18, 2022): 139–67. http://dx.doi.org/10.3390/acoustics4010010.

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Ultrasonic testing of polycrystalline media relies heavily on simulation of the expected signals in order to detect and correctly interpret deviations due to defects. Many effects disturb ultrasonic waves propagating in polycrystalline media. One of them is scattering due to the granular microstructure of the polycrystal. The thus arising so-called microstructural noise changes with grain size distribution and testing frequency. Here, a method for simulating this noise is introduced. We geometrically model the granular microstructure to determine its influence on the backscattered ultrasonic signal. To this end, we utilize Laguerre tessellations generated by random sphere packings dividing space into convex polytopes—the cells. The cells represent grains in a real polycrystal. Cells are characterized by their volume and act as single scatterers. We compute scattering coefficients cellwise by the Born approximation. We then combine the Generalized Point Source Superposition technique with the backscattered contributions resulting from the cell structure to compute the backscattered ultrasonic signal. Applying this new methodology, we compute the backscattered signals in a pulse-echo experiment for a coarse grain cubic crystallized Inconel-617 and a fine grain hexagonal crystallized titanium. Fitting random Laguerre tessellations to the observed grain structure allows for simulating within multiple realizations of the proposed model and thus to study the variation of the backscattered signal due to microstructural variation.

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Anderson, David M., Jayesh Bellare, James T. Hoffman, David Hoffman, Janelle Gunther, and Edwin L. Thomas. "Algorithms for the computer simulation of two-dimensional projections from structures determined by dividing surfaces." Journal of Colloid and Interface Science 148, no. 2 (February 1992): 398–414. http://dx.doi.org/10.1016/0021-9797(92)90179-p.

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Zhang, Yaming, Yaya Hamadou Koura, and Yanyuan Su. "MLP Modeling and Prediction of IP Subnet Packets Forwarding Performance." International Journal of Computational Intelligence and Applications 18, no. 01 (March 2019): 1950006. http://dx.doi.org/10.1142/s1469026819500068.

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In IP networks, packets forwarding performance can be improved by adding more nodes and dividing the network into smaller segments. Being able to measure and predict traffic flows to direct to a given segment can be crucial in respecting traffic shaping, scheduling and QoS. This paper proposes to model network packets forwarding performance for optimization and prediction purposes by using multi-layer feed-forward neural network model that uses sigmoid functions to activate the hidden nodes. Gradient descent technique has been considered to optimize and enhance the MLP accuracy. Simulations of MPL neurons training stages pointed out a relative improvement of the forwarding process when network posses a larger density of neurons. Numerical results validated our theoretical analysis and confirmed that to enhance the forwarding process, it is necessary to divide the network into small segments by optimizing resources allocation.

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Li, Hong Biao. "Fault Detection Way for Computer Networks Based on Multiple Stages." Applied Mechanics and Materials 484-485 (January 2014): 927–32. http://dx.doi.org/10.4028/www.scientific.net/amm.484-485.927.

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To relieve traffic overhead induced by active probing based methods, a new fault detection method, whose key is to divide the detection process into multiple stages, is proposed in this paper. During each stage, only a small region of the network is detected by using a small set of probes. Meanwhile, it also ensures that the entire network can be covered after multiple detection stages. This method can guarantee that the traffic used by probes during each detection stage is small sufficiently so that the network can operate without severe disturbance from probes. Several simulation results verify the effectiveness of the proposed method.

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Pan, K. C., and I. M. Chao. "Analysis of Operating Principles and Flow Field Characteristics for a Diving Ballast Tank." Defence Science Journal 70, no. 5 (October 8, 2020): 564–70. http://dx.doi.org/10.14429/dsj.70.15228.

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Operating principle and flow field characteristics of a diving ballast tank for application in submerged vehicles were investigated in the present study. As understanding the complex changes in the interior air-water two-phase flow field of the ballast tank during the diving process is difficult, this study specifically performed a ballast tank diving experiment. Experimental and numerical simulations to analyse the diving motions of the ballast tank were conducted. Authors comprehensively evaluated the flow field changes in the ballast tank and its surroundings. The experimental and numerical results were compared in terms of the observed displacements and velocities during diving. Both the results indicated similar motion trajectories and velocities. Authors effectively observed the air-water two-phase flow field change inside the ballast tank using this numerical method. Therefore, the numerical model constructed in this study can be useful for analysing the diving motions of ballast tanks and can effectively predict the interior flow field characteristics of a ballast tank.

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Hribernik, Ales, and John J. Moskwa. "Transient Response of a Cross-Flow Charge Air Intercooler and Its Influence on Engine Operation." Journal of Dynamic Systems, Measurement, and Control 122, no. 3 (June 16, 1998): 483–89. http://dx.doi.org/10.1115/1.1286683.

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To examine the influence of intercooler thermal inertia on transient engine operation, a 2D model of an air-to-air, cross-flow heat exchanger has been developed. Finned passages of heat exchanger core have been subdivided into separate channels of charge and cooling air, respectively. A two-step Lax-Wendroff differential method has been used to solve one-dimensional, nonhomentropic, unsteady, compressible fluid flow in each channel. Simultaneously, the Saul’yev explicit method has been applied to compute the 2D temperature distribution along the dividing plate. The Wieting correlation has been used to compute the local convection heat transfer coefficient and friction factor. The model has been verified against steady-state experimental data and then incorporated into an engine cycle simulation program based on “Filling-Emptying” method. Two engine transients have been simulated; the acceleration of the engine from idle to rated engine speed at constant load, and deceleration from rated power to rated torque by increasing the load torque. The first example shows the warming up of the intercooler, while in the second example intercooler temperatures are decreasing. The results have been compared with the predictions of an additional set of simulations, where the NTU-effectiveness method has been used to simulate the intercooler, and the thermal inertia of intercooler has been neglected. The results of both sets of simulations are discussed in the paper. [S0022-0434(00)02003-7]

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Seidel, Tobias, Lena-Marie Ränger, Thomas Grützner, and Michael Bortz. "Simultaneous simulation and optimization of multiple dividing wall columns." Computers & Chemical Engineering 157 (January 2022): 107607. http://dx.doi.org/10.1016/j.compchemeng.2021.107607.

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Azimi, Hamed, Hazhar Hadad, Zakarya Shokati, and Mohammad Sajad Salimi. "Discharge and flow field of the circular channel along the side weir." Canadian Journal of Civil Engineering 42, no. 4 (April 2015): 273–80. http://dx.doi.org/10.1139/cjce-2014-0443.

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The side weir is one of the most important hydraulic structures that is used by hydraulic engineers for adjusting and controlling flow in urban waste collection systems, irrigation and drainage networks. In this study, an equation is proposed for computing side weir discharge located on circular channels. The equation computes the side weir discharge with sufficient accuracy. Then, the RNG k–ε turbulence model is used for simulating the turbulence of the flow field and the free surface flow variations are modeled using volume of fluid scheme. Comparing experimental results with numerical simulations indicates acceptable accuracy of the numerical model. Also, the side weir discharge coefficients, flow free surface variation, behavior of dividing stream surface and variations of stagnation point height for different discharges within a circular channel along a side weir were examined.

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Zhou, J., H. A. Kooijman, and R. Taylor. "Parallel column model for Dividing Wall Column simulations." Computers & Chemical Engineering 125 (June 2019): 114–33. http://dx.doi.org/10.1016/j.compchemeng.2019.02.008.

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46

Tsay, Chung-Biau. "Helical Gears With Involute Shaped Teeth: Geometry, Computer Simulation, Tooth Contact Analysis, and Stress Analysis." Journal of Mechanisms, Transmissions, and Automation in Design 110, no. 4 (December 1, 1988): 482–91. http://dx.doi.org/10.1115/1.3258948.

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The paper covers the solutions to the following problems: (1) Setting up a mathematical model for the involute helical gears; (2) Computer simulation of the conditions of meshing and bearing contact; (3) Investigation of the sensitivity of gears to the errors of manufacturing and assembly; and (4) Stress analysis of the gears. In this paper, the theory of gearing and the concept of differential geometry have been applied to deal with the relations of two mating helical gears and their bearing contact. Computer program for tooth contact analysis (T.C.A.) has been developed for the gears. The T.C.A. computer program makes it possible to simulate gear meshing and bearing contact, and to investigate the influence of gear misalignment on kinematic errors. A method of compensation for the dislocation of bearing contact and for kinematic errors induced by errors of manufacturing and assembly has been proposed. Four numerical examples have also been presented to illustrate the influence of the above-mentioned errors and the method of compensation for the dislocation of bearing contact. Based on the derived mathematical model, an automatic mesh generating computer program—AMG has been developed to define the geometry of the gears and to divide the gear tooth into elements as well as to generate nodal points automatically. The results of T.C.A. provide the locations and directions of the applied loadings for the finite element method (F.E.M.) stress analysis.

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BAIER, Andrzej, Michał MAJZNER, and Krzysztof JAMROZIAK. "ANALYSIS OF RAILWAY CARRIAGE MOVEMENT ON CURVED TRACK." Scientific Journal of the Military University of Land Forces 158, no. 4 (October 1, 2010): 15–28. http://dx.doi.org/10.5604/01.3001.0002.2719.

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The paper focuses on the analysis of movement of a railway carriage on a curved track. The computer model was made in the Siemens PLM Software NX and the simulation process was performed in the ADAMS software. The investigation included the specification of track sections, by dividing the acceleration storage section to a specified speed and distance of movement on the cusp. The simulation was performed using two models: movement without load and when fully loaded. The result of the analysis is shown in the graphs illustrating the pressure of wheel sets on the tracks and the pressure load on the door of the carriage.

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Jaysaval, Piyoosh, Daniil Shantsev, and Sébastien de la Kethulle de Ryhove. "Fast multimodel finite-difference controlled-source electromagnetic simulations based on a Schur complement approach." GEOPHYSICS 79, no. 6 (November 1, 2014): E315—E327. http://dx.doi.org/10.1190/geo2014-0043.1.

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We have developed an efficient numerical scheme for fast multimodel 3D electromagnetic simulations by applying a Schur complement approach to a frequency-domain finite-difference method. The scheme is based on direct solvers and developed with constrained inversion algorithms in view. Such algorithms normally need many forward modeling jobs with different resistivities for the target zone and/or background formation. We geometrically divide the computational domain into two subdomains: an anomalous subdomain, the resistivities of which were permitted to change, and a background subdomain, having fixed resistivities. The system matrix is partially factorized by precomputing a Schur complement to eliminate unknowns associated with the background subdomain. The Schur complement system is then solved to compute fields inside the anomalous subdomain. Finally, the background subdomain fields are computed using inexpensive local substitutions. For each successive simulation, only the relatively small Schur complement system has to be solved, which results in significant computational savings. We applied this approach to two moderately sized 3D problems in marine controlled-source electromagnetic modeling: (1) a deepwater model in which the resistivities of the seawater and the air layer were kept fixed and (2) a model in which focused inversion was performed in a scenario in which the resistivities of the background formation, the air layer, and the seawater were known. We found a significant reduction of the modeling time in inversion that depended on the relative sizes of the constrained and unconstrained volumes: the smaller the unconstrained volume, the larger the savings. Specifically, for a focused inversion of the Troll oil field in the North Sea, the gain amounted up to 80% of the total modeling time.

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Tian Chai, Tian Chai, Han Xue Tian Chai, Xia-Teng Zhou Han Xue, Jian-Zhou Liu Xia-Teng Zhou, and Wen-Yi Wang Jian-Zhou Liu. "Recognition Model and Simulation of Busy Waters in Fishing Area Based on Density Clustering." 電腦學刊 33, no. 4 (August 2022): 169–80. http://dx.doi.org/10.53106/199115992022083304014.

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In this paper, the characteristics of the potential behavior of ships contained in AIS information are con-sidered, in order to ensure the safety of navigation in merchant ships’ fishing areas and reduce the occur-rence of collisions between commercial fishing boats. Based on the DBSCAN density clustering algorithm, the identification model of busy water in fishing areas is developed and applied to Minnan fishery in the Taiwan Strait. In addition, a real ship simulation is performed based on real traffic flow data. The results demonstrate that the proposed model can accurately identify the spatial distribution and scale of busy fishing area, adjust the algorithm parameters according to the merchant ship scale, and generate the target-ed recommended route decision for the fishing area. Finally, the STELLAR EXPRESS is compared with the original route. The obtained results show that the recommended route provides a high safety in the fishing area, while retaining the ship operating costs. The model results can be used as a reference for maritime security departments in order to divide the fishing area warning water, and the identification method provides a novel approach for the safety supervision of maritime department.

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Aldazabal, J., and Carlos García-Mateo. "Computer Simulation of C-N-V Precipitates Evolution Based on Local Concentration Fluctuations." Materials Science Forum 500-501 (November 2005): 719–28. http://dx.doi.org/10.4028/www.scientific.net/msf.500-501.719.

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From a “macroscopic” point of view, steel composition is assumed to vary smoothly along its microstructure. A closer look reveals that, on the atomic level the material composition does not change so smoothly. Single atoms jump randomly along the crystal lattice due to their thermal energy. These random jumps create sporadic zones of the crystal with higher concentration of certain species, and they are responsible for many phenomena, such as precipitation, Ostwald ripening, some phase transformations… This paper proposes a model to simulate the evolution of C-N-V precipitates in microalloyed steels heat treated in the range of warm temperatures (800-900 °C); when the matrix is austenite (fcc), thus taking into account for the local composition fluctuations. The model works by dividing the space into very small cells, containing a single atomic cell each. If during the random movement of atoms a cell that touches a precipitate reaches some critical composition, it is very easy to stick it to the precipitate by changing its “phase”. But it is also possible that some atoms escape from the precipitate by jumping to the austenitic matrix. Both processes happening simultaneously, and which one is leading depends on the atoms energy, i.e. system temperature.

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Journal articles on the topic 'Diving- Computer simulation'

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