12,143 research outputs found

    Design of time delayed chaotic circuit with threshold controller

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    A novel time delayed chaotic oscillator exhibiting mono- and double scroll complex chaotic attractors is designed. This circuit consists of only a few operational amplifiers and diodes and employs a threshold controller for flexibility. It efficiently implements a piecewise linear function. The control of piecewise linear function facilitates controlling the shape of the attractors. This is demonstrated by constructing the phase portraits of the attractors through numerical simulations and hardware experiments. Based on these studies, we find that this circuit can produce multi-scroll chaotic attractors by just introducing more number of threshold values.Comment: 21 pages, 12 figures; Submitted to IJB

    Streaming Current and Streaming Potential Induced by Water Flow Through Porous Media

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    This study was conducted to investigate analytically and experimentally the relationship between the rate of flow of water through porous material and the streaming current and streaming potential induced by this flow. The effect of dissolved salts in the permeating solution and the size of the soil particles was also investigated. Results and conclusions of this study are summarized as follows: A modified procedure using the appropriate delay to insure stead state conditions was used for the measurements of both streaming current and streaming potential. The flow-pressure relationship was the same irrespective of the counter electro-osmosis (resulting from the streaming potential) and the change in salt concentration. Flows through the samples tested thus followed Darcy\u27s Law. The rate of flow (at a constant salt concentration and soil particle diameter) is directly proportional to the induced streaming current and streaming potential. Emperical equations in the form of I = C1q and E = C2q are suggested. A decrease in both streaming current and streaming potential was observed with increase of salt concentrate in the permeating solution. Comparable results were obtained for simulated natural waters and NaCl and KCl solutions, provided that the conductance of the solution was taken as a parameter. A decrease in current and potential was observed with increase of soil particle diameter. a Relationships of the form α = bN and β = C log N + d are suggested to express the effects of particle size and salt concentration on the streaming current and the streaming potential induced by the flow. Induced streaming potential was found to increase with the decrease in temperature. The analytical relationships developed together with the experimental work could probably be used as the basis of a method for measuring the rate of flow through porous material

    A proposed optimized equivalent circuit and performance analysis of dielectric barrier discharge ozone generator

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    Traditionally, low-frequency power supplies are used in dielectric barrier discharge (DBD) ozone generators. These generators require a very high output voltage. This may limit ozone production due to limitations imposed by the dielectric strength of the insulating material. Low-frequency generators also present low efficiency, large volumes, and difficulty in controlling ozone production. On the other hand, the advantages of high frequency DBD ozone generators are the increased power density applied to the chamber electrodes, and the voltage applied to the ozone chamber decreases, allowing for higher ozone production efficiency. From this point of view, in order to enhance and control the DBD ozone generator operating at high frequency, it is necessary to determine all parameter values and optimize the equivalent model for this type of generator. This work presents and proposes the practical methodologies used to extract all parameters of the high voltage high frequency (HVHF) transformer which can be used in these systems. Resonant frequency control techniques are presented in this paper. Elimination of the stray capacitance effect will also be implemented in this paper

    N-particle nonclassicality without N-particle correlations

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    Most of known multipartite Bell inequalities involve correlation functions for all subsystems. They are useless for entangled states without such correlations. We give a method of derivation of families of Bell inequalities for N parties, which involve, e.g., only (N-1)-partite correlations, but still are able to detect proper N-partite entanglement. We present an inequality which reveals five-partite entanglement despite only four-partite correlations. Classes of inequalities introduced here can be put into a handy form of a single non-linear inequality. An example is given of an N qubit state, which strongly violates such an inequality, despite having no N-qubit correlations. This surprising property might be of potential value for quantum information tasks.Comment: 5 page

    PID vs LQR controller for tilt rotor airplane

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    The main thematic of this paper is controlling the main manoeuvers of a tilt rotor UAV airplane in several modes such as vertical takeoff and landing, longitudinal translation and the most important phase which deal with the transition from the helicopter mode to the airplane mode and visversa based on a new actuators combination technique for specially the yaw motion with not referring to rotor speed control strategy which is used in controlling the attitude of a huge number of vehicles nowadays. This new actuator combination is inspired from that the transient response of a trirotor using tilting motion dynamics provides a faster response than using rotor speed dynamics. In the literature, a lot of control technics are used for stabilizing and guarantee the necessary manoeuvers for executing such task, a multiple Attitude and Altitude PID controllers were chosen for a simple linear model of our tilt rotor airplane in order to fulfill the desired trajectory, for reasons of complexity of our model the multiple PID controller doesnt take into consideration all the coupling that exists between the degrees of freedom in our model, so an LQR controller is adopted for more feasible solution of complex manoeuvering, the both controllers need linearization of the model for an easy implementation
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