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Chaouki Mnasri,Dhouha Chorfi,Moncef Gasmi 제어·로봇·시스템학회 2018 International Journal of Control, Automation, and Vol.16 No.5
In this paper, a robust integral sliding mode control problem for networked control systems with multiple data packet losses is investigated. The data packet losses occur in both sensor-to-controller and controllerto- actuator channels in a random way and they are modelled by independent Bernoulli binary distributed white sequences. The considered class of system is also subject to matched uncertainties and external disturbances presence. A specific sliding mode surface which take into consideration the stochastic nature of the system is proposed to generate a stable sliding mode dynamics for closed loop system. An integral sliding mode controller is designed to ensure the reachability of the specified sliding mode domain. Finally, simulation results, carried out on a linearized model of cart pendulum system , illustrate the effectiveness of the proposed approach.
Ahmed Chaouki Megherbi,Hassina Megherbi,Khier Benmahammed,Abdel Ghani Aissaoui,Ahmed Tahour 대한전기학회 2010 Journal of Electrical Engineering & Technology Vol.5 No.4
This paper presents a contribution to parameter identification of a non-linear system using a new strategy to improve the genetic algorithm (GA) method. Since cost function plays an important role in GA-based parameter identification, we propose to improve the simple version of GA, where weights of the cost function are not taken as constant values, but varying along the procedure of parameter identification. This modified version of GA is applied to the induction motor (IM) as an example of nonlinear system. The GA cost function is the weighted sum of stator current and rotor speed errors between the plant and the model of induction motor. Simulation results show that the identification method based on improved GA is feasible and gives high precision.
Selective and Complete Catalytic Oxidation of Natural Gas in Turbulent Fluidized Beds
Klvana, Danilo,Chaouki, Jamal,Guy, Christophe 한국화학공학회 1999 Korean Journal of Chemical Engineering Vol.16 No.4
Turbulent Fluidized Bed (TFB) reactors appears to be ideal for exothermic and fast reactions such as catalytic oxidation of methane. In this paper, a use of TFB reactor for two catalytic oxidation of methane: catalytic combustion of methane and catalytic selective oxidation of methane for the ethylene synthesis is described. Catalytic fluidized bed combustion of methane is shown to be an emerging technology capable of meeting all environmental constraints as far as nitrogen oxides and carbon monoxide are concerned. This reaction carried out in both the bubbling and the turbulent regimes at 450-500℃ shows that the turbulent regime is more favourable. A self-sustained combustion with complete conversion and a zero emission of NO_x and CO was achieved with a mixture of 4% methane in air at 500℃. The two-phase model of Werther [1990], which phenomenologically introduces the enhancement factor due to chemical reaction, predicts quite well the combustor performance. The same model but without enhancement factor (slower reactions) predicts satisfactorily the experimental data for the oxidative coupling of methane and can be used to quantify the influence of homogeneous and catalytic reactions.
Mohamed Hichem Lahrech,Ahmed Chaouki Lahrech,Bachir Abdelhadi 한국철도학회 2023 한국철도학회논문집 Vol.26 No.2
This paper deals with the design and optimization of a 1.2 MVA medium-voltage (MV) power electronic traction transformer (PETT) for an AC 15 kV/16.7 Hz railway grid, in which a simple two-stage multi-cell PETT topology consisting of a bidirectional 170 kW, 2.5 kV AC rms to 6 kV DC power factor corrected (PFC) converter stage followed by a bidirectional isolated 46 kHz, 6 kV to 1.5 kV series resonant DC/DC converter for each cell is presented. This paper presents a methodology that maximizes the converter's efficiency and minimizes the converter's size and weight. Accordingly, the first stage employs 10 kV SiC MOSFETs based on the integrated Triangular Current Mode (iTCM). The second stage uses 10 kV SiC MOSFETs on the MV-side, 3.3 kV SiC MOSFETs on the LV-side, and a medium frequency (MF) MV transformer operating at 46 kHz. MF transformers offer a way to reduce weight and improve energy efficiency, particularly in electric multiple-unit applications. The MF MV transformer requires power electronic converters, which invert and rectify the voltages and currents at the desired operating frequency. The development of high voltage SiC MOSFETs, which can be used instead of Si IGBTs in PETT topologies, increases the operating frequency without reducing the converter's efficiency. The designed MV PETT achieves 98.95% efficiency and 0.76 kVA/kg power density.
Kinetic and thermodynamic evaluation of pyrolysis of jeans waste via coatsredfern method
Rumaisa Tariq,Abrar Inayat,Muhammad Shahbaz,Hassan Zeb,Chaouki Ghenai,Tareq Al-Ansari,김재훈 한국화학공학회 2023 Korean Journal of Chemical Engineering Vol.40 No.1
Used textiles, such as jeans wastes, exhibit a high potential for generating renewable and sustainable energy. However, limited research has been devoted toward investigating the kinetic and thermodynamic parameters of textile wastes during pyrolysis and applying these wastes as feedstock for fuels such as biogas. Therefore, this study investigated the kinetic and thermodynamic aspects of the thermal decomposition of jeans waste to evaluate its potential for sustainable energy production. Jeans waste was heat treated at 50–850 °C under different heating rates of 10–40 °C min−1. Active pyrolysis for the decomposition of jeans waste occurred at temperatures ranging from 250 to 550 °C. Specific Coats-Redfern-type reaction mechanisms were applied to determine the kinetic and thermodynamic variables in the active temperature zone. The thermodynamic parameters (ΔH and ΔG) and activation energies increased when the heating rate was increased from 10 to 30 °C min−1. When the heating rate was further increased to 40 °C min−1, ΔH, ΔG, and the activation energies decreased. For heating rates of 10, 20, 30, and 40 °C min−1, the pre-exponential factors varied in the ranges of 7.4×103 to 1.4×104, 1.8×104 to 5.1×1010, 2.8×104 to 5.3×1010, and 3.6×104 to 3.1×1010 min−1, respectively. In each reaction mechanism model, the entropy changed negatively for all the heating rates examined in this study. This work and its results could serve as a guide for implementing such pyrolysis processes for textile wastes at a practical scale for bioenergy applications.
The Genetic Facets of Dravet Syndrome: Recent Insights
Hinde El Mouhi,Meriame Abbassi,Meryem Jalte,Abdelhafid Natiq,Laila Bouguenouch,Sana Chaouki 대한소아신경학회 2024 대한소아신경학회지 Vol.32 No.2
Dravet syndrome (DS), previously known as severe myoclonic epilepsy of infancy, is a severe epileptic syndrome affecting children, with an incidence of 1/22,000 to 1/49,900 live births annually. Characterized by resistant and prolonged seizures, it often leads to intellectual impairment, with males being twice as susceptible as females. Its clinical features include recurrent seizures triggered by fever initially, but later occurring spontaneously, developmental delays, behavioral issues, and movement disorders. Sodium voltage-gated channel alpha subunit 1 (SCN1A) mutations, observed in about 90% of cases, are usually de novo, while mutations in other genes, such as protocadherin 19 (PCDH19), gamma-aminobutyric acid type A receptor subunit gamma 2 (GABRG2), and sodium voltage-gated channel alpha subunit 2 (SCN2A), can also contribute to the condition. Next-generation sequencing aids in identifying these genetic abnormalities. First-line treatments include anticonvulsant drugs such as valproate, clobazam, stiripentol, topiramate, and bromide. Second-line treatments for drug-resistant DS include stiripentol, fenfluramine, and cannabidiol. This literature review provides a comprehensive update on the genetic underpinnings of DS, highlighting SCN1A's predominant role and the emerging significance of other genes. Moreover, it emphasizes novel therapeutic approaches for drug-resistant forms, showcasing the efficacy of newer drugs such as stiripentol, fenfluramine, and cannabidiol. This synthesis contributes to our understanding of the genetic landscape of DS and informs clinicians about evolving treatment strategies for enhanced patient care.
Production of rare earth oxides from raw ore in fluidized bed reactor
Adrián Carrillo García,Mohammad Latifi,Said Samih,Jamal Chaouki 한국공업화학회 2020 Journal of Industrial and Engineering Chemistry Vol.85 No.-
This study deals with the calcination of a rare earth bearing ore to produce rare earth oxides in afluidizedbed reactor, with the aim of demonstrating the advantage of calcining bigger particles to decomposestable minerals such as monazite by its mineral association within a particle. Rare earth oxides wereproduced by the decomposition of its bearing minerals, bastnäsite and monazite along with the gangues. During the calcination, bastnäsite decomposed at relatively low temperature while monazite reacted CaOat high temperature. The formation of cracks, revealed by BET and SEM analysis, allowed the particle’sdegassing while the size remained constant, thus describing a crackling core behavior. The association of monazite to calcite for bigger particles ( 60 mesh) allowed its decomposition toproduce rare earth oxides with a monazite conversion of 50 %. Also, an extraction process comprised ofcalcination and mild acid leaching enriched the rare earth oxides in the ore by 3.34 and improvedleaching efficiency of the gangues compared to smaller size (enrichment ration of 2.35). Using biggerparticle sizes in the upstream process of a mining industry, i.e. comminution, can also reduce the energyconsumption.