scholarly journals The Effect of First-Order Bending Resonance of Wheelset at High Speed on Wheel-Rail Contact Behavior

2013 ◽  
Vol 5 ◽  
pp. 296106 ◽  
Author(s):  
Shuoqiao Zhong ◽  
Xinbiao Xiao ◽  
Zefeng Wen ◽  
Xuesong Jin
Keyword(s):  
High Speed ◽  
Contact Behavior ◽  
First Order

scholarly journals A High-Speed DSP Engine for First-Order Hold Digital Phase Modulation in 28-nm CMOS

2018 ◽  
Vol 65 (12) ◽  
pp. 1959-1963 ◽  
Author(s):  
Enrico Roverato ◽  
Marko Kosunen ◽  
Jerry Lemberg ◽  
Mikko Martelius ◽  
Kari Stadius ◽  
...  
Keyword(s):  
Phase Modulation ◽  
High Speed ◽  
First Order ◽  
Digital Phase ◽  
28 Nm

scholarly journals Mathematical Model of a Three-Phase Induction Machine in a Natural abc Reference Frame Utilizing the Method of Numerical Integration of Average Voltages at the Integration Step and Its Application to the Analysis of Electromechanical Systems

2019 ◽  
Vol 2019 ◽  
pp. 1-13
Author(s):  
Oleksiy Kuznyetsov
Keyword(s):  
Reference Frame ◽  
High Speed ◽  
Numerical Models ◽  
Second Order ◽  
Integration Step ◽  
Electromechanical Systems ◽  
Suitable Alternative ◽  
First Order ◽  
Operation Speed ◽  
Three Phase

Recent advances in the real-time simulation of electric machines are linked with the increase in the operation speed of the numerical models retaining the calculation accuracy. We propose utilizing the method of average voltages at the integration step (AVIS) for the design of a three-phase induction machine’s model in its natural abc reference frame. The method allows for avoiding rotational e.m.f. calculation at every step; in turn, the electromagnetic energy conversion is accounted by the change of flux-linkage. The model is integrated into the object-oriented environment in C++ for designing the computer models of electromechanical systems. The design of the model of an electromechanical system utilizing the proposed approach is explained in an example. The behavior of the numerical models of a three-phase IM has been compared for the set of conventional numerical methods as well as first- and second-order AVIS. It has been demonstrated that both first- and second-order AVIS methods are suitable tools for high-speed applications, namely, AVIS provides higher maximum possible integration step (e.g., first-order AVIS provides 4 times higher than the second-order Runge–Kutta method, and the second-order AVIS provides 2.5 times higher than the first-order method). Therefore, we consider the most preferable order of the AVIS method for the high-speed applications is the second order, while the first order may be a suitable alternative to increase the calculation speed by 30% with the acceptable decrease in the accuracy.

ACTION OF HIGH SPEED ELECTRONS ON METHANE, OXYGEN AND CARBON MONOXIDE

1930 ◽  
Vol 3 (3) ◽  
pp. 241-251 ◽  
Author(s):  
J. C. McLennan F.R.S. ◽  
J. V. S. Glass B.A.
Keyword(s):  
Carbon Dioxide ◽  
Carbon Monoxide ◽  
Water Vapor ◽  
Formic Acid ◽  
Total Pressure ◽  
High Speed ◽  
Reaction Rate ◽  
First Order ◽  
Gaseous Products ◽  
Retarding Effect

This paper deals with the action of cathode rays on gases and gas mixtures. Methane, methane-oxygen mixtures, carbon monoxide and carbon monoxide-oxygen mixtures were examined. Methane gave small percentages of hydrogen and ethane. Methane and oxygen mixtures gave as gaseous products, carbon monoxide, carbon dioxide and hydrogen, the only other products being water and formic acid. The relative proportions of the products do not vary widely under a wide variation of conditions.The reaction was found to be of the first order with respect to pressure. The reaction rate increases linearly with the voltage up to a certain value, after which it becomes nearly independent of the voltage.The action of cathode rays on carbon monoxide produces carbon dioxide and a solid brown suboxide which is extremely soluble in water, and its composition corresponds to a formula (C3O)n. If the carbon monoxide is moist, no visible amount of solid or liquid is found and there is less carbon dioxide.Carbon monoxide-oxygen mixtures under the action of cathode rays form carbon dioxide. Presence of water vapor has a retarding effect on the reaction. For mixtures of the same composition the reaction rate is proportional to the total pressure. For dry mixtures the product increases with the carbon monoxide present; when moist it is much less, and independent of the carbon monoxide.

scholarly journals Heterogeneity and Convergence of Olfactory First-Order Neurons Account for the High Speed and Sensitivity of Second-Order Neurons

2014 ◽  
Vol 10 (12) ◽  
pp. e1003975 ◽  
Author(s):  
Jean-Pierre Rospars ◽  
Alexandre Grémiaux ◽  
David Jarriault ◽  
Antoine Chaffiol ◽  
Christelle Monsempes ◽  
...  
Keyword(s):  
High Speed ◽  
Second Order ◽  
First Order

The Dynamics of a Ball-Type Balancer System Equipped with a Pair of Free-Moving Balancing Masses

2001 ◽  
Vol 123 (4) ◽  
pp. 456-465 ◽  
Author(s):  
Jaan-Rong Kang ◽  
Chang-Po Chao ◽  
Chun-Lung Huang ◽  
Cheng-Kuo Sung
Keyword(s):  
High Speed ◽  
Multiple Scales ◽  
Design Guidelines ◽  
Disk Drives ◽  
Rotating System ◽  
Radial Vibrations ◽  
First Order ◽  
System A ◽  
Autonomous Differential Equations ◽  
Steady State Solutions

This study is devoted to evaluate the performance of a ball-type balancer system that is installed in high-speed optical disk drives. The ball-type balancer system, composed of a circular runway and free-moving balls inside, is designed for reducing radial vibrations induced by the inherent unbalance of the rotating system. A balancer system equipped with a pair of balls is considered in this study for its capability to reach possible near-elimination of radial vibrations as opposed to the serious sizing problem of a single balancing-ball system. A mathematical model is first established to describe the dynamics of the balls and rotor system. Utilizing the method of multiple scales and assuming the smallness of radial vibrations, the system dynamics on the slow time scale is represented by eight first-order autonomous differential equations, which accommodate the radial vibratory motions and ball behaviors. The steady-state solutions of these slow equations are then solved and their stability analyzed to predict settling ball positions. The residual vibrations are computed to evaluate the performance of the balancer system and then the design guidelines are distilled for engineers to design the balancer system.

Robust Adaptive Controllers for Interconnected Mechanical Systems: Influence of Types of Interconnections on Time-Invariant and Time-Varying Systems

1994 ◽  
Vol 116 (3) ◽  
pp. 456-473 ◽  
Author(s):  
Sunil K. Singh ◽  
Lin Shi
Keyword(s):  
State Space ◽  
High Speed ◽  
Linear Time ◽  
Direct Method ◽  
Time Varying ◽  
Adaptive Controllers ◽  
First Order ◽  
Time Varying Systems ◽  
Robust Adaptive ◽  
Time Invariant

We investigate robust adaptive controller designs for interconnected systems when no exact knowledge about the structure of the nonlinear interconnections between various subsystems is available. In this study, we concentrate on several different types of systems. We deal with both linear time-invariant (LTI) and linear time-varying (LTV) systems with nonlinear interconnections. For LTI systems, we examine the following types of interconnections: • interconnections that are bounded by first order polynomials in state space; • slowly time varying interconnections; • interconnections bounded by higher-order polynomials in state-space together with input channel interconnections. For LTV systems we deal with interconnections bounded by first-order polynomials in state space. We show that the nature of the nonlinear interactions influences the adaptation laws. We use the direct method of Lyapunov for the design of adaptive controllers for tracking in such systems. We investigate issues such as stability, transient performance and steady-state errors, and derive quantitative estimates and analytical bounds for various different adaptive controllers. For time-varying systems, we analyze the effect of the time variations of parameters and interactions and propose a modified adaptive control scheme with better performance. Simulation results are presented to validate our conclusions. We also investigate these results experimentally on a two-link robot manipulator. Experimental results validate theoretical conclusions and demonstrate the usefulness of such robust adaptive controllers for high-speed motions in uncertain systems.

Integral Hull Form Parameters and a High-Speed Approximation to Michell’s Integral

1964 ◽  
Vol 8 (01) ◽  
pp. 12-15
Author(s):  
Jerry W. Cuthbert
Keyword(s):  
High Speed ◽  
Hull Form ◽  
First Order ◽  
The Subject

Michell's integral, the wave-making resistance formula of first-order thin ship theory, has been the subject of much study and discussion. Among the results of the study is the expansion at vanishing Froude number2 in terms of derivative properties of the hull form. The purpose of this paper is to show that the behavior of Michell's integral at high Froudenumber is related to certain integral properties or form parameters. The demonstration consists of the derivation of a high-speed approximation to Michell's integral in terms of these parameters.

Sign in / Sign up

Export Citation Format

Share Document