24 research outputs found
A Fast and Straightforward Solver for Generation Allocation Problem Including Losses using A Hopfield Network
Abstract In this paper, a fast solver for generation allocation problem including transmission losses using a Hopfield Neural Network (HNN) approach is presented. The proposed HNN is distinguished by a direct computation method mapped to the generation allocation problem of thermal generators commonly known as economic dispatch (ED). The developed HNN employs a linear input-output model for the transfer function of neurons. Formulations for solving the ED problem are explored, through the application of these formulations; direct computation instead of iterations for solving the problem without losses becomes possible. Not like the usual Hopfield methods, which select the weighting factors of the energy function by trials, the proposed method determines the corresponding factors only by calculations. To include the transmission losses, a dichotomy method is combined to the Hopfield Neural Network iteratively. The effectiveness of the developed method is identified through its application to the 15-unit system. Computational results manifest that the method has a lot of excellent performances
Influence of the geometrical parameters of a dielectric barrier discharge reactor on the subsequent tribocharging of granular polymers
International audienceTribocharging of insulating materials is a pivotal step in several electrostatic applications in which the charge value has an important consequence on the outcome of the process. The Dielectric Barrier Discharge (DBD) at atmospheric pressure is an excellent energetic plasma source having the aptitude to change surface properties and, thereby, to enhance triboelectric charging of granular insulating materials. This paper aimed to investigate the influence of dielectric barrier geometrical parameters on the triboelectric charge of the DBD-treated Polypropylene (PP) and Polyvinyl Chloride (PVC) mm-size granules. The studied parameters include the air gap between the upper barrier and the surface of the granular layer, the number of granular layers, as well as the material forming the dielectric barrier and its position. After being treated for 3 s, the granules were triboelectrically charged in a vibratory device for 2 min. The charge the DBD-treated and untreated particles acquire by tribocharging was measured using a Faraday pail connected to an electrometer. Experimental results show that the air gap and the properties of the dielectric barrier can influence the mean value of the discharge current and enhance significantly the triboelectric charge of DBD-treated granules. Best results were obtained when the air gap did not exceed 4 mm and material with high permittivity was used as a barrier
Triboelectric Charging of Granular Polymers Previously Exposed to Dielectric Barrier Discharges in Atmospheric Air
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Effect of Dielectric Barrier Discharge Exposure on the Triboelectric Charging of Granular Plastics
International audienceThe aim of the present paper is to study the feasibility of continuous dielectric barrier discharge (DBD) treatment of granular plastic materials in view of improving their triboelectric charging ability. The effects of the following DBD parameters were studied: the amplitude and the frequency of the applied high voltage, the thickness of the dielectric barrier, the distance between the electrodes of the reactor as well as the speed of the conveyor that was used for the transfer of the granular materials though the non-thermal plasma zone. The study was carried out on mm-size Polyethylene particles. It was found that the charge of DBD treated particles increases with the applied high voltage and decrease with the speed of the conveyor. Both the distance between the electrodes and the thickness of the dielectric barrier have a remarkable effect on the charge acquired after DBD treatment. Within the experimental domain of this study, the frequency of the high voltage does not significantly affect the efficiency of the tribocharging process
Dielectric barrier discharge treatment of granular plastic mixtures in view of their tribo-electrostatic separation
International audienceSuccessful electrostatic separation of granular plastic mixtures is strongly conditioned by the effective triboelectric charging of their constituents. The aim of this article is to demonstrate that appropriate exposure to a dielectric barrier discharge (DBD) at atmospheric pressure changes the triboelectric properties of plastics and favors their separation under the action of electric field forces. The experiments were conducted with nine different plastics originating from waste electric and electronic equipment [acrylonitrile butadiene styrene, high-impact polystyrene (HIPS), polycarbonate (PC), Cristal PC, polyethylene (PE), polypropylene (PP), polystyrene (PS), Cristal PS, and polyvinyl chloride (PVC)] using a rotating cylinder tribocharging device and a roll-type electrostatic separator. The cylinder of the device was made of either high-density PE or PVC. The comparison between the results of triboelectric charging and electrostatic separation of DBD-exposed and unexposed granules pointed out the effectiveness of nonthermal plasma treatment of the plastic wastes. Most of DBD-exposed granules acquire a negative charge, whereas the majority of the plastics considered in this study got positively charged, if not pretreated in the nonthermal plasma reactor. The modifications the DBD exposure induces on the triboelectric series highly affect the electrostatic separation of six different mixtures (PE–HIPS, PE–PP, PE–PVC, PP–HIPS, PP–PVC, and PVC–HIPS)
Tribo-aero-electrostatic separator for coarse granular insulating materials
International audienceThe tribo-aero-electrostatic separator achieves the selective sorting of mixed granular insulating materials in a fluidized bed affected by an electric field orthogonally oriented to the direction of the fluidization air. The aim of the present paper is to optimize the design and the operation of such a separator, i.e. maximize the total mass of the granules collected at the two electrodes that generate the electric field. The experiments were performed for four different electrode configurations. The granular mixtures to be separated were composed of Acrylonitrile Butadiene Styrene (ABS) and High Impact Polystyrene (HIPS) originating from the recycling of waste electric and electronic equipment (WEEE). The typical granule size was in the range 2 to 4.5 mm. The highest separation efficiency was obtained when the electric field in the active zone was intensified by the use of an additional electrode connected to the ground and when the collecting electrodes were covered by a thin insulating layer, preventing charge leakage from the particles in contact with them
Factors That Affect Tribocharging of Polyethylene (PE) Granules After Exposure to a Dielectric Barrier Discharge (DBD)
International audienceTriboelectric charging is used in many applications including electricity nanogeneration, safety or electrostatic separation of insulating materials. Insulating granules charge must be the highest in electrostatic separators so that the electric field forces allow their separation. Dielectric barrier discharge (DBD), used for ozone production, depollution or surface treatment, is able to change the triboelectric properties of insulating materials. The aim of this study is to improve the triboelectric charging of polyethylene particles by exposing them to an atmospheric DBD. Signal shape, exposure duration, voltage amplitude, and frequency, which rule the DBD, are studied. After exposing the particles to DBD, they are charged in a vibratory device during 5 min. Then, particles are put in a Faraday pail connected to an electrostatic voltmeter to measure the acquired charge. Results show that the square waveform has the best effect and that the duration of the DBD treatment should not exceed 10 s, for the amplitude of the applied voltage of 21 kV