scholarly journals Comparison of Three Measures to Promote National Fitness in China by Mathematical Modeling

2014 ◽  
Vol 2014 ◽  
pp. 1-7
Author(s):  
Pan Tang ◽  
Daqing Xu ◽  
Qing Dai ◽  
Tingting Huang
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Physical Exercise ◽  
Three Dimensional ◽  
Chinese Government ◽  
Model Parameters ◽  
National Bureau ◽  
Short Period ◽  
Key Parameter

In this paper we established a mathematical model for national fitness in China. Based on a questionnaire and data of the General Administration of Sport of China and the National Bureau of Statistics of China, the dynamics for three classes of people are expressed by a system of three-dimensional ordinary equations. Model parameters are estimated from the data. This study indicated that national fitness put out by the Chinese government is reasonable. By finding the key parameter, the best measure to promote national fitness is put forward. In order to increase the number of people who frequently participate in sport exercise in a short period of time, if only one measure can be chosen, guiding people who never take part in physical exercise will be the best measure.

Design, modeling and simulation of a control surface-less tri-tilt-rotor UAV

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Vinoth Kumar Annamalai ◽  
Selvakumaran Thunaipragasam
Keyword(s):  
Mathematical Model ◽  
Flight Control ◽  
Pid Controller ◽  
Control Model ◽  
Control Surface ◽  
Model Parameters ◽  
Content Type ◽  
Tilt Rotor ◽  
Short Period ◽  
Thrust Vector

Purpose The purpose of this study is to design a flight control model for a control surface-less (CSL) tri-tilt-rotor (TTR) unmanned aerial vehicle (UAV) based on a Proportional Integral Derivative (PID) controller to stabilize the altitude and attitude of the UAV subjected to various flying conditions. Design/methodology/approach First, the proposed UAV with a tilting mechanism is designed and analyzed to obtain the aerodynamic parameters. Second, the dynamics of the proposed UAV are mathematically modeled using Newton-Euler formation. Then, the PID controller is implemented in the simulation model to control flight maneuvers. The model parameters were implemented in a mathematical model to find the system’s stability for various flight conditions. The model was linearized to determine the PID gain values for vertical take-off and landing, cruise and transition mode. The PID controller was tuned to obtain the desired altitude and attitude in a short period. The tuned PID gain values were implemented in the PID controller and the model was simulated. Findings The main contribution of this study is the mathematical model and controller for a UAV without any control surface and uses only a thrust vector control mechanism which reduces the complexity of the controller. The simulation has been carried out for various flight conditions. The altitude PID controller and the attitude PID controller for CSL-TTR-UAV were tuned to obtain desired altitude and attitude within the optimum duration of 4 s and deviation in the attitude of 8%, which is within the allowable limit of 14%. The findings obtained from the simulation revels that the altitude and attitude control of the CSL-TTR-UAV was achieved by controlling the rpm of the rotor and tilt angle using the PID controller. Originality/value A novel CSL TTR UAV mathematical model is developed with a dual tilting mechanism for a tail rotor and single axis tilt for the rotors in the wing. The flight control model controls the UAV without a control surface using a PID controller for the thrust vector mechanism.

scholarly journals EFFICIENCY OF WATER FILTERING PROCESS DEPENDING ON THE FILTER LAYER POROSITY AND FLOW - A MATHEMATICAL MODEL

2018 ◽  
Vol 22 (4) ◽  
Author(s):  
TIRTOACA (IRIMIA) OANA ◽  
NEDEFF VALENTIN ◽  
PANAINTE-LEHADUS MIRELA ◽  
TOMOZEI CLAUDIA
Keyword(s):  
Applied Sciences ◽  
Mathematical Modeling ◽  
Mathematical Model ◽  
Experimental Approach ◽  
Three Dimensional ◽  
Filtration Efficiency ◽  
Robust Method ◽  
Intake Flow ◽  
The Mathematical Model ◽  
Filter Layer

<p>Mathematical modeling represents a challenge for any researcher or engineers that working in the field of applied sciences. The experimental approach to the water filtering process allowed achieving and verification a three-dimensional mathematical model, depending on the intake flow of the filter, the porosity of the filter layer and the nature of the filter layer. The mathematical model was developed and verified using the software Table Curve 3D. It was found that the mathematical model proposed offers a viable and robust method for determining the mechanical filtration efficiency of water.</p>

scholarly journals EFFICIENCY OF WATER FILTERING PROCESS DEPENDING ON THE FILTER LAYER POROSITY AND FLOW - A MATHEMATICAL MODEL

2016 ◽  
Vol 22 (4) ◽  
pp. 54-61
Author(s):  
OANA TIRTOACA IRIMIA ◽  
VALENTIN NEDEFF ◽  
MIRELA PANAINTE-LEHADUS ◽  
CLAUDIA TOMOZEI
Keyword(s):  
Applied Sciences ◽  
Mathematical Modeling ◽  
Mathematical Model ◽  
Experimental Approach ◽  
Three Dimensional ◽  
Filtration Efficiency ◽  
Robust Method ◽  
Intake Flow ◽  
The Mathematical Model ◽  
Filter Layer

Mathematical modeling represents a challenge for any researcher or engineers that working in the field of applied sciences. The experimental approach to the water filtering process allowed achieving and verification a three-dimensional mathematical model, depending on the intake flow of the filter, the porosity of the filter layer and the nature of the filter layer. The mathematical model was developed and verified using the software Table Curve 3D. It was found that the mathematical model proposed offers a viable and robust method for determining the mechanical filtration efficiency of water.

Fabrication and property of auxetic warp-knitted spacer structures with mesh

2017 ◽  
Vol 88 (19) ◽  
pp. 2206-2213 ◽  
Author(s):  
Yuping Chang ◽  
Pibo Ma
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Inclination Angle ◽  
Three Dimensional ◽  
Simple Mathematical Model ◽  
Model Based ◽  
Fabric Density ◽  
Auxetic Structure ◽  
Experimental Sampling

For the purpose of reconstructing a three-dimensional auxetic structure adopting spacer warp-knitting techniques, a simple mathematical model based on the structure of auxetic warp-knitted spacer hexagonal meshes was established and several samples were produced using an E22 RD7/2-12EN warp-knitting machine. It is predicted from synthesizing the results of both mathematical modeling and experimental sampling that auxetic performance of this structure mainly depends on the contraction distortion before stretching in three directions, especially in the y-axis. When it comes to knitting parameters, yarn fineness, machine gauge, fabric density, movement of guide bars, and inclination angle of wales all matter for the auxetic performance, which is also affected by the stiffness of materials and the lodging of spacer yarns. It is also concluded that successive inlaying in the same direction of the spacer guide bar favors contraction distortion in the y-axis, which means auxetic performances can be more easily achieved in this way.

scholarly journals Mathematical Modeling of the Coaxial Quadrotor Dynamics for Its Attitude and Altitude Control

Energies ◽  
2021 ◽  
Vol 14 (5) ◽  
pp. 1232
Author(s):  
Wojciech Giernacki ◽  
Jarosław Gośliński ◽  
Jagoda Goślińska ◽  
Tadeo Espinoza-Fraire ◽  
Jinjun Rao
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Viscous Friction ◽  
Control Techniques ◽  
Aerial Vehicle ◽  
Altitude Control ◽  
Selection Of ◽  
Three Dimensional Space

In this paper, an easily implementable coaxial quadrotor model and its validation on data from a real unmanned aerial vehicle (UAV), are presented. The proposed mathematical model consists of two parts: description of orientation and position of the UAV in the three-dimensional space. It takes into consideration the gyroscopic effect, influence of the Coriolis force, viscous friction and a several drag-like effects (blade flapping, rotor drag, translational drag and profile drag). In contrast to multirotor models available in the literature, this one is characterized by complementarity in relation to the available control techniques. Depending on selection of these techniques, the model can be narrowed (simplified) to meet the needs without the loss of behaviour adequacy to a real UAV.

scholarly journals INVESTIGATION OF THE GRID MODEL AND TURBULENCE MODEL PARAMETERS INFLUENCE ON QUALITY OF TURBINE ROTOR BLADE TIP CLEARANCE AREA AERODYNAMIC PROCESSES MODELING

2021 ◽  
pp. 67-78
Author(s):  
Diana Popova ◽  
◽  
Denis Popov ◽  
Nikita Samoylenko ◽  
◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Numerical Methods ◽  
Turbulence Model ◽  
Rotor Blade ◽  
Three Dimensional ◽  
Turbulence Models ◽  
Design Stage ◽  
Model Parameters ◽  
Grid Model

Aerodynamic processes mathematical modeling is carried out using numerical methods. Now the level of development of software numerical methods of three-dimensional gas-dynamic modeling of processes in turbomachinery makes it possible to determine with high accuracy the main characteristics of units at the design stage. It significantly reduces the time and cost of production. This article proposes a methodology for installation and improving the mathematical and grid model of HPT rotor blade to improve the quality of three-dimensional modeling. Aerodynamic processes mathematical modeling in aircraft turbojet engine blade rows is carried out using numerical methods. Grid model settings and turbulence model significantly affect the results qualitative characteristics and the calculations duration. This article proposes a methodology for grid model constructing based on local intense vortex formation and flow mixing places thickening. The influence of the grid and turbulence models parameters are estimated on the kinetic energy losses amount and secondary flows structure. The design model includes the building geometric model, preparation of the grid model and description of the turbulence model. Influence of grid and BSL and SST turbulence models on results of turbine blade aerodynamic calculation is considered in this article. Basic recommendations for the construction of mathematical and grid models in the ANSYS for uncooled rotor blades have been developed.

scholarly journals Three-Dimensional Mathematical Investigation of Dynamic and Hydrostatic Pressure Distributions on Planing Hulls

2013 ◽  
Vol 2013 ◽  
pp. 1-13 ◽  
Author(s):  
Parviz Ghadimi ◽  
Sasan Tavakoli ◽  
Abbas Dashtimanesh ◽  
Seyed Reza Djeddi
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Hydrostatic Pressure ◽  
Total Pressure ◽  
Three Dimensional ◽  
Hydrodynamic Pressure ◽  
Empirical Equations ◽  
3 Dimensional ◽  
Pressure Distributions ◽  
Mathematical Investigation

A mathematical model is utilized in order to calculate three-dimensional pressure distributions on planing hulls. This type of modeling is able to determine the hydrodynamic and hydrostatic pressures acting on the bottom of these hulls. As a result, the total 3-dimensional pressure exerted on the planing hull as a sum of hydrostatic and hydrodynamic pressures can be evaluated. Empirical equations introduced in previous works have been used as the fundamentals for the present mathematical modeling method. The obtained results are compared against available experimental results and results of empirical equations in order to validate the proposed method. The outcome of the -squared tests conducted on these comparisons shows favorable accuracy of the results. After evaluation of hydrodynamic pressure, the effects of trim and deadrise angles and wetted length on the 3-dimensional pressure distribution are analyzed. Finally, the total pressure on planing hull and the effect of velocity coefficients are studied.

scholarly journals Modelling and Simulation of Deformation and Failure of Reinforced Concrete Beams under Four-Point Bending

2021 ◽  
Vol 14 (6) ◽  
pp. 679-689
Author(s):  
Vasily A. Belyaev ◽  
Keyword(s):  
Mathematical Model ◽  
Reinforced Concrete ◽  
Concrete Beams ◽  
Three Dimensional ◽  
Reinforced Concrete Beams ◽  
Model Parameters ◽  
Deformation And Failure ◽  
Four Point Bending ◽  
Nonlinear Stress ◽  
Dimensional Simulation

A new mathematical model for the four-point bending of reinforced concrete beams is developed and investigated. The model takes into account multi-modulus concrete behavior, nonlinear stress-strain relationships, and damage evolution. An algorithm for a numerical implementation of the model is proposed. The corresponding boundary value problem is solved by the hp-version of the least-squares collocation method in combination with an acceleration of an iterative process based on Krylov subspaces and parallelizing. Special attention is given to the influence of mathematical model parameters on the results of numerical simulation. The results are compared with experimental data and three-dimensional simulation. A satisfactory agreement is shown

Application of the method of mathematical modeling for forecasting channel deformations at the underwater crossing of the main pipeline

2020 ◽  
Vol 10 (6) ◽  
pp. 599-609
Author(s):  
Valery А. Gruzdev ◽  
◽  
Georgy V. Mosolov ◽  
Ekaterina A. Sabayda ◽  
◽  
...  
Keyword(s):  
Mathematical Modeling ◽  
Mathematical Model ◽  
Roughness Coefficient ◽  
Computational Domain ◽  
Channel Deformations ◽  
Geological Surveys ◽  
Kuban River ◽  
The Stability ◽  
Protective Structures

In order to determine the possibility of using the method of mathematical modeling for making long-term forecasts of channel deformations of trunk line underwater crossing (TLUC) through water obstacles, a methodology for performing and analyzing the results of mathematical modeling of channel deformations in the TLUC zone across the Kuban River is considered. Within the framework of the work, the following tasks were solved: 1) the format and composition of the initial data necessary for mathematical modeling were determined; 2) the procedure for assigning the boundaries of the computational domain of the model was considered, the computational domain was broken down into the computational grid, the zoning of the computational domain was performed by the value of the roughness coefficient; 3) the analysis of the results of modeling the water flow was carried out without taking the bottom deformations into account, as well as modeling the bottom deformations, the specifics of the verification and calibration calculations were determined to build a reliable mathematical model; 4) considered the possibility of using the method of mathematical modeling to check the stability of the bottom in the area of TLUC in the presence of man-made dumping or protective structure. It has been established that modeling the flow hydraulics and structure of currents, making short-term forecasts of local high-altitude reshaping of the bottom, determining the tendencies of erosion and accumulation of sediments upstream and downstream of protective structures are applicable for predicting channel deformations in the zone of the TLUC. In all these cases, it is mandatory to have materials from engineering-hydro-meteorological and engineering-geological surveys in an amount sufficient to compile a reliable mathematical model.

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