Critical System Parameters and Process Control

Author(s):  
Carl Edlund ◽  
Michael Lewis

Graphical User Interfaces (GUIs) are becoming increasingly common for application software in process control. Conventional interfaces display the states of a system without conveying the constraints which drastically reduce the evolutions which must be considered. Our model resolves this difficulty by presenting system parameters in the context of ecological constraints mirroring those of the underlying process. A simulation of a simple steam plant with five different GUIs was used. The displays were a conventional Dials display, a Mimic display, an Object display, a Seesaw analogue, and a Fluidtank analogue. Poor over-all performance in maintaining specified values was found for the Seesaw and the Object displays. The Dials and the Mimic displays performed similarly but with greater accuracy. The best control was observed in the experimental Fluidtanks display. These Findings are consistent with our hypotheses.


1999 ◽  
Vol 121 (2) ◽  
pp. 300-306 ◽  
Author(s):  
K. Dasgupta ◽  
A. Mukherjee ◽  
R. Maiti

In this paper the authors have presented an integrated study of an orbital rotor Low Speed High Torque (LSHT) hydrostatic unit in a Hydrostatic Transmission (HST) System and an attempt has been made to estimate some critical parameters of such class of geometrically complex machine. Owing to the close tolerance in between the rotor-stator interface of the motor leakage takes place from the high pressure to the low pressure chamber and is difficult to estimate during operation. Based on the simulation and experimental investigations, a semi-empirical approach is proposed here to estimate its interchamber leakage resistance and for that the machine need not be disassembled. Using the actual parametric values, the overall dynamic model of the plant has been validated experimentally.


Author(s):  
Mohammad Katibeh ◽  
Onur Bilgen

Abstract The so-called solid-state ornithopter concept seeks to employ piezoelectric materials to generate flapping motion instead of relying on conventional mechanisms and multi-component actuation systems. The motion can be induced on a wing-like partially-clamped composite substrate with a piezocomposite device (i.e. the Macro-Fiber Composite actuator.) In this research, a design for a flapping wing is proposed based on the analysis of critical system parameters such as geometric properties and boundary conditions. A series of finite element simulations are conducted based on the variation of those parameters. Consequently, the effects of parameters on the structural response is studied. Also, modal analysis is done to examine the effects of geometric parameters on the resonant frequencies of the system. Heaving and pitching responses are examined.


1997 ◽  
Vol 20 (6) ◽  
pp. 352-356 ◽  
Author(s):  
G. Vogt ◽  
A. Schrefl ◽  
R. Mitteregger ◽  
D. Falkenhagen

A novel field generator specially designed to examine the influence of low frequency magnetic fields on specific cell material was constructed and characterized. The exposure unit described in this paper consists of a controller unit and three sets of coils. The field generator permits a precious definition of the revelant signal parameters and allows the superposition of alternating current (AC) and direct current (DC) magnetic fields. Critical system parameters were monitored continuously. The three sets of coils, each arranged in the Helmholtz Configuration were characterized. After data processing and visualization the results showed a constant and homogeneous field within the experimental area. The special coil design also allows their use in an incubator.


2019 ◽  
Vol 30 (20) ◽  
pp. 3008-3024
Author(s):  
Mehmet Murat Gozum ◽  
Amirreza Aghakhani ◽  
Ipek Basdogan

The popularity of laminated composite plate-like structures is increasing in various engineering applications. Piezoelectric patches with electrical circuit elements can be integrated into these structures for shunt damping applications. For analyzing the shunt damping performance of these systems, precise modeling tools are required, which consider the two-way electromechanical coupling between the piezo-patches and the host plate. This study aims to identify the system parameters which affect the electromechanical coupling coefficient, a metric for measuring the effectiveness of mechanical-to-electrical energy conversion. For that purpose, a thorough investigation is performed to determine the critical system parameters and their combined effects on the electromechanical coupling coefficient of laminated composite plates with surface-bonded piezo-patches. First, the first four natural frequencies of the electromechanical system are obtained using the Rayleigh–Ritz method for various patch sizes. Then, the electromechanical coupling coefficient variations for a different set of system parameters are presented. Later, to demonstrate the applicability of the developed methodology for a broader frequency range, four independently shunted piezo-pairs are attached to the plate. The contours of electromechanical coupling coefficient values with respect to ply angle and patch-pair size are presented for the first four modes. Finally, the vibration amplitudes are successfully reduced for these modes using the optimal system parameters.


1998 ◽  
Vol 120 (1) ◽  
pp. 50-56 ◽  
Author(s):  
N. A. El-Esnawy ◽  
J. F. Wilson

The lateral dynamics and stability of two full vehicles in tandem are investigated. The nonlinear differential equations of motion of this four-axle articulated vehicle system are presented in matrix form and then linearized. The critical forward velocity of the steady state for oversteering conditions is derived in a closed form, and the criteria for understeer, neutral steer, or oversteer are given. Uncertainty of the critical forward velocity and its sensitivity to errors in the system parameters are evaluated using the root mean square method. Conditions for nonoscillatory and oscillatory instabilities of the linearized vehicle system are given. Effects of the critical system parameters (mainly the mass distribution) on the stability are investigated.


1979 ◽  
Vol 46 ◽  
pp. 65-74 ◽  
Author(s):  
A.C. Fabian ◽  
J.E. Pringle ◽  
J.A.J. Whelan ◽  
J.A. Bailey

Abstract.Recent photometric and spectroscopic observations of the dwarf nova system Z Cha are discussed. Methods for constraining the system parameters are applied and the disc emissivity is deduced as a function of radius. Indications are found that the disc shrinks in size with increasing time after outburst.


1956 ◽  
Vol 48 (2) ◽  
pp. 81-84
Author(s):  
William Priestley ◽  
B. Dudenbostel, Jr.

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