scholarly journals Sludge Filtration Resistance Model Based on Electrical Resistance Analogy

2018 ◽  
Vol 09 (01) ◽  
pp. 1-12
Author(s):  
L. W. Arimieari ◽  
J. O. Ademiluyi
Keyword(s):  
Electrical Resistance ◽  
Filtration Resistance ◽  
Model Based ◽  
Resistance Model

Implementation and Investigation of a Compact, Powerful System for Diagnosis and Control of Shape Memory Alloys in Technical Applications

2019 ◽  
Author(s):  
Max Kaiser ◽  
Nils Neblung ◽  
Martin Gurka
Keyword(s):  
Phase Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Electrical Resistance ◽  
Control Strategies ◽  
Memory Systems ◽  
Constant Load ◽  
Resistance Change ◽  
Model Based ◽  
And Control

Abstract In this paper we present the development, implementation and testing of a compact system for diagnosis and control of actuators based on metallic shape memory alloys (SMA). Using NiTi-SMA, very compact, cost-effective and lightweight actuation systems can be realized. In applications where the SMA is activated by internal Joule heating or its condition is diagnosed by the self-sensing of its electrical resistance, an electrical system capable of reliably measuring very small resistance changes (< 1 ohm) without affecting the phase-state of the SMA is required. In addition, the system must offer the possibility to evaluate the nonlinear, hysteresis-afflicted behavior of the SMA and to handle this difficulty, e.g. utilizing a model-based control. This paper presents a simple compact and adaptive system based on a microcontroller that meets these requirements. Detailed functional tests were carried out with the system to establish a correlation between the change in electrical resistance in the range < 200 mOhm and the current strain state of the actuator. For this purpose, a first series of tests was performed, with the SMA wires working against a constant load. In a second tests series, the SMA wires worked against springs of different stiffness. The use of a microcontroller enables simple implementation of different control strategies. The control system for the non-linear resistance change utilizes a fuzzy logic which divides the control algorithm into three regimes. In the regime of the martensitic phase transformation a PI-controller is used. The state of actuators with an absolute electrical resistance < 1 Ohm and a resistance change < 200 mohm associated with the phase transformation can be precisely measured and controlled with an accuracy < 10 mohm. The system can be configured with little effort for different tasks and shape memory systems of different sizes. Furthermore, it is possible to implement more complex control algorithms up to model-based controllers.

Electrical Resistance Model of a Bilayer-Coated Spherical Contact

2018 ◽  
Vol 8 (9) ◽  
pp. 1614-1620 ◽  
Author(s):  
Oleg Korchevnik ◽  
Roman Goltsberg ◽  
Yuri Kligerman ◽  
Izhak Etsion
Keyword(s):  
Electrical Resistance ◽  
Spherical Contact ◽  
Resistance Model

scholarly journals Design of compression reinforcement in reinforced concrete membrane

2012 ◽  
Vol 5 (6) ◽  
pp. 820-847
Author(s):  
T. F. Silva ◽  
J. C. Della Bella
Keyword(s):  
Reinforced Concrete ◽  
Compressive Stress ◽  
Tensile Strain ◽  
Design Methods ◽  
Tension Stress ◽  
Model Based ◽  
Strength Limit ◽  
Resistance Model

This paper presents a method to design membrane elements of concrete with orthogonal mesh of reinforcement which are subject to compressive stress. Design methods, in general, define how to quantify the reinforcement necessary to support the tension stress and verify if the compression in concrete is within the strength limit. In case the compression in membrane is excessive, it is possible to use reinforcements subject to compression. However, there is not much information in the literature about how to design reinforcement for these cases. For that, this paper presents a procedure which uses the model based on Baumann's [1] criteria. The strength limits used herein are those recommended by CEB [3], however, a model is proposed in which this limit varies according to the tensile strain which occur perpendicular to compression. This resistance model is based on concepts proposed by Vecchio e Collins [2].

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