Model simplification and optimization of a passive wind turbine generator

In this paper, the design of a “low cost full passive structure” of wind turbine system without active electronic part (power and control) is investigated. The efficiency of such device can be obtained only if the design parameters are mutually adapted through an optimization design approach. For this purpose, sizing and simulating models are developed to characterize the behavior and the efficiency of the wind turbine system. A model simplification approach is presented, allowing the reduction of computational times and the investigation of multiple Pareto-optimal solutions with a multiobjective genetic algorithm. Results show that the optimized wind turbine configurations are capable of matching very closely the behavior of active wind turbine systems which operate at optimal wind powers by using a MPPT control device.     

Colorectal lesions predisposing to cancer

Precursors of colorectal carcinoma are adenomatous polyps, sporadic or arising in familial adenomatous polyposis and Lynch syndrome and chronic inflammatory lesions related to ulcerative colitis and Crohn's disease. The adenoma-carcinoma sequence is well established and early detection and removal of colorectal adenomas is thought to prevent colorectal cancer in high risk asymptomatic persons, i.e. subjects over 45 years, with personal or familial history of adenomas and colorectal cancers. The precancerous potential of adenomatous polyps varies according to tissue type, with increased risk with the extent of the villous component, high grade of dysplasia, large size greater than 1 cm and multiple adenomas. The development of de novo colorectal cancer from normal mucosa with flat adenomas has been recently emphasized. The risk of colonic cancer in patients with ulcerative colitis and Crohn's disease is controversed.     

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.     

Performances improvements and torque ripple minimization for VSI fed induction machine with direct control torque

This paper describes a torque ripple reduction technique with constant switching frequency for direct torque control (DTC) of an induction motor (IM). This method enables a minimum torque ripple control. In order to obtain a constant switching frequency and hence a torque ripple reduction, we propose a control technique for IM. It consists of controlling directly the electromagnetic torque by using a modulated hysteresis controller. The design methodology is based on space vector modulation (SVM) of electrical machines with digital vector control. MATLAB simulations supported with experimental study are used. The simulation and experimental results of this proposed algorithm show an adequate dynamic to IM; however, the research can be extended to include synchronous motors as well. The implementation of the proposed algorithm is described. It doesn’t require any PI controller in the torque control loop. The hardware inverter is controlled digitally using a Texas Instruments TMS320F240 digital signal processor (DSP) with composed C codes for generating the required references. The results obtained from simulation and experiments confirmed the feasibility of the proposed strategy compared to the conventional one.     

Metric anticipation to manage mobility in mobile mesh and ad hoc wireless networks

In mobile ad hoc networks (MANETs), node mobility management is performed by the routing protocol. It may use metrics to reflect link state/quality. But, the delay between measures of the link quality and its integration in the route computation is very detrimental to the mobility management. Consequently, routing protocols may use lossy links for a few seconds leading to a significant performance deterioration. In this paper, we propose a new routing metric technique calculation which aims at anticipating link quality. Basically, the idea is to predict metric values a few seconds in advance, in order to compensate the delay involved by the link quality measurement and their dissemination by the routing protocol. Our technique is based on measurements of signal strength and is integrated in two classical routing metrics: ETX (expected transmission count) and ETT (expected transmission time). Validations are performed through both simulations and a testbed experimentation with OLSR as routing protocol. NS-3 simulations show that our metric may lead to a perfect mobility management with a packet delivery ratio of 100%. Experiments on a testbed prove the feasibility of our approach and show that this technique reduces the packet error rate by a factor of 3 in an indoor environment compared to the classical metrics calculation.     

Study of C.I. Reactive Yellow 145, C.I. Reactive Red 238, and C.I. Reactive Blue 235 dyestuffs in order to use them in color formulation. Part 1: characterization and compatibility

Generally, textile dyeing is based on a mixture of several dyestuffs used in different proportions to achieve the desired-colors. The dyes used in a mixture should react with the fiber similarly; thus they must be compatible among themselves. So, to realize mixtures it is indispensable to study the compatibility of dyes, in order to ensure optimal dyeing formulation. This paper describes the characterization and studies the compatibility of three cold bifunctionnal reactive dyes (C.I. Reactive Yellow 145, C.I. Reactive Red 238, and C.I. Reactive Blue 235) in order to explore the possibility to use them in mixtures. The dye compatibility was studied based on several criteria such as dye extinction coefficients, exhaustion and fixation yield rates, adsorption kinetics, and adsorption isotherms. The exhaustion and fixation yield rates of all three dyes was compared between them and their adsorption kinetics and adsorption isotherms models were drawn and discussed. Between the different studied models, the Elovich model presents the best model describing the kinetics of different dyes, and Freundlich model presents the best model for analyzing the adsorption isotherms. The obtained results show that the analyzed dyes are perfectly compatible and have the same dyeing properties. They present close extinction coefficients as well as similar exhaustion and fixation yield rates.