Stability and robustness of fuzzy adaptive control of nonlinear systems

In this paper, we propose a new approach that guarantees the stability and robustness of an adaptive control law of a nonlinear system.The control diagram proposed contains a Takagi–Sugeno–Kang fuzzy controller (TSK-FC) and a training block allowing the online adaptation of the FC parameters. The adaptation algorithm used is based on the gradient with minimization of the quadratic error between the system output and that desired by using the direct method of Lyapunov. However, our approach considers the gradient step of each adaptive FC parameter to be bound. This approach was applied to the control of an inverted pendulum. The results obtained confirm well the validity of such an adaptation especially the guarantee of the pendulum stability and the robustness of its control with respect to the disturbances introduced on the FC parameters and the pendulum itself.     

Experimental evaluation of quinolinium and isoquinolinium derivatives as corrosion inhibitors of mild steel in 0.5 M H<Subscript>2</Subscript>SO<Subscript>4</Subscript> solution

The 1-methylquinolinium iodide (I) Qui⁺, I^– and 2-methylisoquinolinium iodide isoQui⁺, I^– were investigated as a corrosion inhibitors for mild steel in sulfuric acid using electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The results indicated that the corrosion inhibition efficiency and extent of surface coverage were increased with increase in inhibitors concentrations. Polarization curves revealed that both inhibitors acted as a mixed-type inhibitor. The thermodynamic parameters were evaluated for corrosion inhibition process. The adsorption of both inhibitors on mild steel surface obeyed Langmuir adsorption isotherm.     

On the order reduction of induction machine: during start-up

The starting of an induction machine at constant voltage and frequency is studied. A new method of order reduction and decoupling is given. It leads to approximate analytical expressions which describe with accuracy the dangerous torque oscillations which occur during induction machine start-up     

Distributed Graph Traversals by Relabelling Systems with Applications

Graph traversals are in the basis of many distributed algorithms. In this paper, we use graph relabelling systems to encode two basic graph traversals which are the broadcast and the convergecast. This encoding allows us to derive formal, modular and simple encoding for many distributed graph algorithms. We illustrate this method by investigating the distributed computation of a breadth-first spanning tree and the distributed computation of a minimum spanning tree. Our formalism allows to focus on the correctness of a distributed algorithm rather than on the implementation and the communication details.     

Two step three time scale reduction of doubly fed machine models

A three time scale reduction method is presented, which consists of two successive two time scale seductions. The advantage is that only small order systems of equations are dealt with. This method is applied to doubly fed synchronous machines, and is compared with other methods. A discussion of the dynamic behavior according to inertia and operating point is also included     

In Vitro and In Vivo Pharmaco-Toxicological Characterization of 1-Cyclohexyl-x-methoxybenzene Derivatives in Mice: Comparison with Tramadol and PCP

1-cyclohexyl-x-methoxybenzene is a novel psychoactive substance (NPS), first discovered in Europe in 2012 as unknown racemic mixture of its three stereoisomers: ortho, meta and para. Each of these has structural similarities with the analgesic tramadol and the dissociative anesthetic phencyclidine. In light of these structural analogies, and based on the fact that both tramadol and phencyclidine are substances that cause toxic effects in humans, the aim of this study was to investigate the in vitro and in vivo pharmacodynamic profile of these molecules, and to compare them with those caused by tramadol and phencyclidine. In vitro studies demonstrated that tramadol, ortho, meta and para were inactive at mu, kappa and delta opioid receptors. Systemic administration of the three stereoisomers impairs sensorimotor responses, modulates spontaneous motor activity, induces modest analgesia, and alters thermoregulation and cardiorespiratory responses in the mouse in some cases, with a similar profile to that of tramadol and phencyclidine. Naloxone partially prevents only the visual sensorimotor impairments caused by three stereoisomers, without preventing other effects. The present data show that 1-cyclohexyl-x-methoxybenzene derivatives cause pharmaco-toxicological effects by activating both opioid and non-opioid mechanisms and suggest that their use could potentially lead to abuse and bodily harm.     

Production of a halotolerant lipase from Halomonas sp. strain C2SS100: Optimization by response-surface methodology and application in detergent formulations

The aim of this work was to optimize the production of a new lipase by a halotolerant bacterial strain Halomonas sp. C2SS100, by means of the response-surface methodology (RSM). The process parameters having the most significant effect on lipase production were identified using the Plackett–Burman screening design-of-experiments. Then, Box–Behnken design was applied to optimize lipase activity and the quadratic regression model of the lipase production was built. Indeed, the lipase yield was increased, and the value obtained experimentally (39 ± 2 U/ml) was very close to the rate predicted by the model (40.3 U/ml). Likewise, optimization of parameters by RSM resulted in 2.78-fold increase in lipase activity. These findings provide the first report on lipase production and optimization by a halotolerant bacterial strain belonging to Halomonas genus. Afterward, the biochemical properties of the produced lipase were studied for apply in oil stains removal. The crude lipase showed a maximum activity at 60°C and at pH ranging from 7 to 10. It displayed an important stability at high temperature, pH, and NaCl. Interestingly, this bacterial lipase exhibited a prominent stability toward some commercial solid and liquid detergents after 30 min of incubation at 50°C. The capability of the crude lipase to eliminate stain was ascertained on polycotton fabric pieces stained with lubricating oil. Whether with the addition of hot water alone or of a commercially available detergent, lipase is able to considerably boost the elimination of oil stains. The actual findings highlight the capacity of Halomonas sp. lipase for energy-efficient biocatalytic application.     

A New Adaptive Neuro-sliding Mode Control for Gantry Crane

This paper presents a new adaptive neuro-sliding mode control for gantry crane as varying rope length. This control method derived from combining the sliding surfaces of three subsystem of the gantry crane (trolley position, rope length, anti-swing) to draw out two system sliding surfaces: the trolley position with the anti-swing and the rope length and the anti-swing. On the based of the sliding mode control principle, drawn out the equivalent controller and the switching controller for gantry crane. But due to the uncertain parameters-nonlinear model of gantry crane with the bound disturbances, combining the neural approximate method, defined the neural controller and the compensation controller for the difference between the equivalent controller and the neural controller for two system control inputs: trolley position and rope length. The adaptive control laws for these controllers were deduced from Lyapunov’s stable criteria to asymptotically stabilize the sliding surfaces. Simulation studies are performed to illustrate the effectiveness of the proposed control.