Chaos Synchronization Using Active Control and Backstepping Control: A Comparative Analysis

This paper examines the synchronization performance of two widely used chaos synchronization techniques: active control and backstepping control. It is shown that the two methods have excellent performance, with the active control marginally outperforming the backstepping control in terms of transient analysis. However, the complexity of active controllers suggests that the backstepping control would be more attainable in engineering applications

Summary of booster propulsion/vehicle impact study results

Hydrogen, RP-1, propane, and methane were identified by propulsion technology studies as the most probable fuel candidates for the boost phase of future launch vehicles. The objective of this study was to determine the effects of booster engines using these fuels and coolant variations on representative future launch vehicles. An automated procedure for integrated launch vehicle, engine sizing, and design optimization was used to optimize two stage and single stage concepts for minimum dry weight. The two stage vehicles were unmanned and used a flyback booster and partially reusable orbiter. The single stage designs were fully reusable, manned flyback vehicles. Comparisons of these vehicle designs, showing the effects of using different fuels, as well as sensitivity and trending data, are presented. In addition, the automated design technique is described

Bifurcation and Chaos in Coupled Ratchets exhibiting Synchronized Dynamics

The bifurcation and chaotic behaviour of unidirectionally coupled deterministic ratchets is studied as a function of the driving force amplitude ($a$) and frequency ($\omega$). A classification of the various types of bifurcations likely to be encountered in this system was done by examining the stability of the steady state in linear response as well as constructing a two-parameter phase diagram in the ($a -\omega$) plane. Numerical explorations revealed varieties of bifurcation sequences including quasiperiodic route to chaos. Besides, the familiar period-doubling and crises route to chaos exhibited by the one-dimensional ratchet were also found. In addition, the coupled ratchets display symmetry-breaking, saddle-nodes and bubbles of bifurcations. Chaotic behaviour is characterized by using the sensitivity to initial condition as well as the Lyapunov exponent spectrum; while a perusal of the phase space projected in the Poincar$\acute{e}$ cross-section confirms some of the striking features.Comment: 7 pages; 8 figure

Generalized squeezed-coherent states of the finite one-dimensional oscillator and matrix multi-orthogonality

A set of generalized squeezed-coherent states for the finite u(2) oscillator is obtained. These states are given as linear combinations of the mode eigenstates with amplitudes determined by matrix elements of exponentials in the su(2) generators. These matrix elements are given in the (N+1)-dimensional basis of the finite oscillator eigenstates and are seen to involve 3x3 matrix multi-orthogonal polynomials Q_n(k) in a discrete variable k which have the Krawtchouk and vector-orthogonal polynomials as their building blocks. The algebraic setting allows for the characterization of these polynomials and the computation of mean values in the squeezed-coherent states. In the limit where N goes to infinity and the discrete oscillator approaches the standard harmonic oscillator, the polynomials tend to 2x2 matrix orthogonal polynomials and the squeezed-coherent states tend to those of the standard oscillator.Comment: 18 pages, 1 figur

Design and Development of Bomb Defusing Robot Controlled by Gesture

Neutralizing explosives is one of precision and accuracy tasks handled by law enforcement personnel; it can be error-prone and life threatening. This paper seeks to demonstrate an improved use of remote controlled robots for Explosive Ordinance Disposal (EOD) using gesture manipulation. There exist a variety of EOD robots capable of handling different types of Explosives. This work is concerned with a class of EOD that uses the principle of wireless transmission of data packets within the ISM 2.4GHz spectrum, electrical H-Bridge circuits, servo-mechanisms and potential division in its underlying architecture and operation. The class is a fully integrated and non-autonomous system used by Law Enforcement Agents as First Responders. The developed EOD robot possesses two arms for gripping and manipulation. The robot arms are controlled by inputting commands on a handheld remote control or by human arm gesticulation. For gesture control, flexing the index finger closes the arm’s gripper, flexing the thumb moves the wheels forward and backward, tilting the back of the controlling hand tilts the robot’s elbow and rotating the wrist controls the waist

Generalized Adaptive Backstepping Synchronization for Non-Identical Parametrically Excited Systems

In this paper, we investigate the synchronization of chaotic systems consisting of non-identical parametrically excited oscillators. The backstepping design, which is a recursive procedure that combines the choice of a Lyapunov function with the design of a controller is generalized and employed so as to achieve global chaos synchronization between a parametrically excited gyroscope and each of the parametrically excited pendulum and Duffing oscillator. Numerical simulations are implemented to verify the results

Quantum vibrational resonance in a dual-frequency driven Tietz-Hua quantum well

We investigate the response of a quantum particle in the Tietz-Hua quantum potential driven by biharmonic fields – a low and a very high frequency force. The response is characterized by the occurrence of a maximum in the first-order transition probability amplitude, |s|2 , under the influence of the applied fields. It is shown that in the absence of the high-frequency component of the applied fields, |s|2 shows a distinct sequence of resonances; whereas an increase in the amplitude of the high-frequency field induces minima in |s|2. However, the |s|2 maximum occurs in the low-frequency regime where it may be considered otherwise weak in the presence of a single harmonic force

Synchronization and Control of directed transport in chaotic ratchets via active control,” Phys

Abstract Using a technique derived from nonlinear control theory, we demonstrate that two identical inertial ratchets transporting particles in two directions can be synchronized such that both ratchets transport particles in a desired direction. This novel approach to control of directed transport is applicable when there are multiple co-existing attractors in phase space transporting particles in different directions. Numerical simulations are employed to illustrate the approach

Increase in phenolic compounds of Coriandrum sativum L. after the application of a Bacillus halotolerans biofertilizer

[EN]BACKGROUND: There is an urgent need for a new sustainable way of satisfying the increasing demand for food worldwide. One of the main challenges is replacing chemical fertilizers with biofertilizers, which include plant root-associated beneficial microorganisms. The present study reports, for the first time, the effects of SCCPVE07 bacterial strain with respect to improving not only plant development, but also the nutritional content and bioactive compounds content of Coriandrum sativum L., one of the most economically important crops, even for plant growth under salinity stress. RESULTS: Innoculated coriander plants (C. sativum L.) showed an increase in potassium, carbon, calcium and iron content. A significant improvement in phenolic compounds contents was also observed. The contents of 5-O-caffeoylquinic acid, cinnamic acid, 4-methoxy-cinnamic acid hexoside, K-3-O rutinoside, Q-3-O-rutinoside, Q-3-O-glucoside and Q-3-O-glucuronide were significantly enhanced. Moreover, an efficient bacterial root colonization and a noted growth promotion were demonstrated. Bacterial genome was sequenced and analysed. Gene coding related to Plant growth promotion (PGP) mechanisms and proteins involved in plant defence from salinity or in the metabolism of phenolic compounds, such as quercetin 2,3-dioxygenase and phenolic acid decarboxylase, were identified. CONCLUSION: The results obtained in the present study show, for the first time, the beneficial effects of the inoculation of a bacterial Bacillus halotolerans biofertilizer on coriander crops with respect to increasing the content in bioactive compounds and plant development