Mathematical Model of a Gas Discharge Arrester Based on Physical Parameters

2014 ◽  
Vol 29 (3) ◽  
pp. 985-992 ◽  
Author(s):  
Janez Ribic ◽  
Joze Vorsic ◽  
Joze Pihler
Keyword(s):  
Mathematical Model ◽  
Gas Discharge ◽  
Physical Parameters

scholarly journals Identical Limb Dynamics for Unilateral Impairments through Biomechanical Equivalence

Symmetry ◽  
2021 ◽  
Vol 13 (4) ◽  
pp. 705
Author(s):  
Fatemeh Rasouli ◽  
Kyle B. Reed
Keyword(s):  
Mathematical Model ◽  
Numerical Solution ◽  
Dynamic Models ◽  
Assistive Devices ◽  
Assistive Device ◽  
Human Walking ◽  
Physical Parameters ◽  
Gait Rehabilitation ◽  
And Performance ◽  
Two Sides

Dynamic models, such as double pendulums, can generate similar dynamics as human limbs. They are versatile tools for simulating and analyzing the human walking cycle and performance under various conditions. They include multiple links, hinges, and masses that represent physical parameters of a limb or an assistive device. This study develops a mathematical model of dissimilar double pendulums that mimics human walking with unilateral gait impairment and establishes identical dynamics between asymmetric limbs. It introduces new coefficients that create biomechanical equivalence between two sides of an asymmetric gait. The numerical solution demonstrates that dissimilar double pendulums can have symmetric kinematic and kinetic outcomes. Parallel solutions with different physical parameters but similar biomechanical coefficients enable interchangeable designs that could be incorporated into gait rehabilitation treatments or alternative prosthetic and ambulatory assistive devices.

Microstructures in Solidification Simulation of Electron Beam Scanning with MC in Molten Pool

2014 ◽  
Vol 898 ◽  
pp. 168-172 ◽  
Author(s):  
Rong Wang ◽  
Yi Liu ◽  
De Qiang Wei
Keyword(s):  
Mathematical Model ◽  
Temperature Field ◽  
Electron Beam ◽  
Grain Growth ◽  
Molten Pool ◽  
Growth Process ◽  
Solidification Process ◽  
Optical Microscope ◽  
Physical Parameters ◽  
Beam Scanning

The solidification microstructure of electron beam scanning is important to product performance. The solidification process of molten pool temperature field and 2D simulation mathematical model of grain growth was established based on heat transfer and the physics of growth process of crystal grains. The heat distribution, thermal physical parameters and influence of thermal radiation on the temperature field was considered during the analysis process. The distribution of temperature field was solved by COMSOL. The process of solidification was simulated by using Monte Carlo method. Using optical microscope to observe the solidified microstructure of bath. The simulation results show that the mathematical model can reasonably describe the grain growth process, the temperature field and the simulation of microstructure morphology.

Simplified Adaptive Nonlinear Robust Controller for Linearized Pantagraph-Type Manipulator

1995 ◽  
Vol 7 (3) ◽  
pp. 242-249 ◽  
Author(s):  
Kiyotaka Izumi ◽  
◽  
Keigo Watanabe ◽  
Masatoshi Nakamura ◽  
◽  
...  
Keyword(s):  
Mathematical Model ◽  
Physical Parameters ◽  
Additional Mass ◽  
Robust Controller ◽  
End Effector ◽  
Linear Controller ◽  
The Mathematical Model ◽  
Nonlinear Robust

If physical parameters are adjusted suitably in the pantagraph-type manipulator, the mathematical model becomes linear so that we can apply a linear controller. However, when the manipulator has an additional mass as an end-effector, the linear controller does not work well because the resultant model becomes nonlinear. In this paper, we propose a simplified adaptive nonlinear robust controller which we can apply to the manipulator, irrespective of the system linearity or nonlinearity. The effectiveness of the controller is illustrated by some simulations.

Analysis of Vibrating Natural Frequency of Pressure Pipeline

2011 ◽  
Vol 421 ◽  
pp. 98-101
Author(s):  
Ting Yue Hao
Keyword(s):  
Mathematical Model ◽  
Natural Frequency ◽  
Critical Flow ◽  
Physical Parameters ◽  
Beam Model ◽  
Instability Condition ◽  
Coupling Vibration ◽  
Critical Flow Velocity ◽  
Pressure Pipeline ◽  
The Mathematical Model

The pressure pipeline is simplified as the beam model with two simple supported ends. The mathematical model is established, considering influence of the fluid-solid coupling vibration. Then the critical flow velocity is obtained by calculation and solving. By analyzing the practical numerical example，the influence of physical parameters on the first three-order natural frequency is discussed. Using Matlab software for programming, the instability condition of pressure pipeline is obtained, which is consistent with the result of numerical calculation.

Vibration Analysis of a Vertical Roller Mill: Modeling and Validation

2014 ◽  
Author(s):  
Engin H. Çopur ◽  
Metin U. Salamci ◽  
Selahattin Gülbeyaz
Keyword(s):  
Mathematical Model ◽  
Vibration Analysis ◽  
Compressive Force ◽  
Vibration Characteristics ◽  
Physical Parameters ◽  
Roller Mill ◽  
Vibration Tests ◽  
Working Parameters ◽  
The Mathematical Model ◽  
Vertical Roller

In this paper, vibration characteristics of a Vertical Roller Mill (VRM) are studied by using physical parameters of an operating VRM. The mathematical model is derived and simulated for a set of working parameters. Mechanical properties of the grinding material and the physical properties of the mechanical construction are used in the vibration model in order to obtain more realistic results. Simulation results are presented which give critical frequencies of the VRM. The effects of the hydraulic compressive force to the vibration characteristics are investigated. The effects of the material feeding rate (which affects the mineral thickness to be grinded) to the vibration characteristics are also simulated. In order to validate the mathematical model, a set of experimental vibration tests are performed on the VRM. Vibrations are measured during the run-down procedure of the VRM in order to determine natural frequencies of the mill as well as excitation frequencies of the system. The measurements showed the validity of the proposed mathematical model for the vibration analysis of the VRM.

Mathematical model of a non-stationary process of accumulation of gas hydrates, confined to deep-water mud volcanoes

2021 ◽  
Author(s):  
Alexey L. Sobisevich ◽  
Elena I. Suetnova ◽  
Ruslan A. Zhostkov
Keyword(s):  
Mathematical Model ◽  
Gas Hydrates ◽  
Stationary Process ◽  
Sedimentary Basins ◽  
Physical Parameters ◽  
Continental Margins ◽  
Mud Volcanoes ◽  
Environment Temperature ◽  
Hydrate Saturation ◽  
Sea Mud

<p>Large amounts of methane hydrate locked up within marine sediments are associated to mud volcanoes. We have investigated by means of mathematical modeling the unsteady process of accumulation of gas hydrates associated with the processes of mud volcanism. A mathematical model has been developed. The system of equations of the model describes the interrelated processes of filtration of gas-saturated fluid, thermal regime and pressure, and accumulation of gas hydrates in the seabed in the zone of thermobaric stability of gas hydrates. The numerical simulation of the accumulation of gas hydrates in the seabed in the deep structures of underwater mud volcanoes has been carried out using the realistic physical parameters values. The influence of the depth of the feeding reservoir and the pressure in it on the evolution of gas hydrate accumulations associated with deep-sea mud volcanoes is quantitatively analyzed. Modeling quantitatively showed that the hydrate saturation in the zones of underwater mud volcanoes is variable and its evolution depends on the geophysical properties of the bottom environment (temperature gradient, porosity, permeability, physical properties of sediments) and the depth of the mud reservoir and pressure in it. The volume of accumulated gas hydrates depends on the duration of the non-stationary process of accumulation between eruptions of a mud volcano. The rate of hydrate accumulation is tens and hundreds times the rate of hydrate accumulation in sedimentary basins of passive continental margins.</p>

Estimation of nitric oxide production and reactionrates in tissue by use of a mathematical model

1998 ◽  
Vol 274 (6) ◽  
pp. H2163-H2176 ◽  
Author(s):  
Mark W. Vaughn ◽  
Lih Kuo ◽  
James C. Liao
Keyword(s):  
Nitric Oxide ◽  
Mathematical Model ◽  
Smooth Muscle ◽  
Vascular Smooth Muscle ◽  
Consumption Rate ◽  
Physical Parameters ◽  
No Production ◽  
Rate Expression ◽  
Order Rate ◽  
Lack Of Information

Nitric oxide (NO) produced by the vascular endothelium is an important biologic messenger that regulates vessel tone and permeability and inhibits platelet adhesion and aggregation. NO exerts its control of vessel tone by interacting with guanylyl cyclase in the vascular smooth muscle to initiate a series of reactions that lead to vessel dilation. Previous efforts to investigate this interaction by mathematical modeling of NO diffusion and reaction have been hampered by the lack of information on the production and degradation rate of NO. We use a mathematical model and previously published experimental data to estimate the rate of NO production, 6.8 × 10−14μmol ⋅ μm−2 ⋅ s−1; the NO diffusion coefficient, 3,300 μm2s−1; and the NO consumption rate coefficient in the vascular smooth muscle, 0.01 s−1 (1st-order rate expression) or 0.05 μM−1 ⋅ s−1 (2nd-order rate expression). The modeling approach is discussed in detail. It provides a general framework for modeling the NO produced from the endothelium and for estimating relevant physical parameters.

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