Karim Medles - Academia.edu (original) (raw)
Papers by Karim Medles
IEEE Industry Applications Magazine, 2000
HE AIM OF THIS article is to point out the characteristics of Shewhart and CUSUM charts when appl... more HE AIM OF THIS article is to point out the characteristics of Shewhart and CUSUM charts when applied to electrostatic separation processes and validate their ability to detect special events that may be indicators of out-of-control situations. This article also shows how the effectiveness of statistical process control (SPC) can be improved by using the cumulative sum (CUSUM) chart. Experiments were carried out with a mixture of bronze and aluminum particles (size range: 1-2 mm) by using a platetype electrostatic separator. The mobile-average Shewhart and CUSUM charts were established based on 20 electrostatic separation tests performed under optimal operating conditions. An out-of-control situation was simulated, and the response of the process was
2015 IEEE Industry Applications Society Annual Meeting, 2015
The principal objective of this paper is to present a determination calculation program of the ex... more The principal objective of this paper is to present a determination calculation program of the exact profile of the level of radionoise of existing lines E.H.V and on project according to the frequency. The method used for the determination of the disturbing field is an analytical method based on the theory of the modal propagation.
IEEE Transactions on Industry Applications, 2015
ABSTRACT The two- conveyor-electrodes tribo- aero- electrostatic separator is a device patented i... more ABSTRACT The two- conveyor-electrodes tribo- aero- electrostatic separator is a device patented in 2010 and intended to sort granular mixtures of insulating materials in a fluidized bed affected by an electric field perpendicular to the direction of the fluidizing air. The prototype of the device has proven its efficiency for the separation of insulating granules of size less than or equal to 2 mm, attaining excellent recovery rates. Unfortunately, its performances were less satisfactory for larger particles (2 to 4.5 mm). The objective of this work is to propose three modifications of the construction of this device, in order to increase the hourly throughput and improve the purity of the separated products. A primary analysis shows that the designer of the equipment can act on two factors namely the charge Q acquired by the granules and the electric field intensity E. Numerical simulations enabled the optimization of the electric field distribution in the active zone of the separator and an experimental study was carried out in order to identify the best conditions for particle charging by triboelectric effect. The tests were carried out for four configurations of the electrode system, by using a mixture of acrylonitrile butadiene styrene (ABS) and high impact polystyrene (HIPS) originated from grinding out-of-use computer cases. The typical granule size was of the order of 2 to 4.5 mm. The experimental approach validated a change in the position of the fluidized bed with respect to the conveyor electrodes, to increase the residence time of the granular materials and hence the amount of electric charge acquired by each particle. In order to intensify the electrical field, two solutions were tested and validated: (1) add a grounding electrode in the proximity of the high-voltage electrodes; (2) dispose vertically the high voltage electrodes. For the tested materials, the vertical arrangement of the electrodes gave the best hourly throughput rates and purity of the separated products.
Le but de cet article est de présenter une méthode à utiliser dans la détermination du point opti... more Le but de cet article est de présenter une méthode à utiliser dans la détermination du point optimal de fonctionnement d’un séparateur électrostatique de matériaux granulaires. La méthode consiste dans l’application des plans d’expériences afin de déterminer les paramètres du processus. Le logiciel MODDE 5.0 à été utilisé pour ce but.
When designing line of electric power transport, it is necessary to dimension these installations... more When designing line of electric power transport, it is necessary to dimension these installations according to the high magnetic fields. This present paper gives a method to calculate and represent the magnetic field around a three-phase line; it proposes to bring to the owner of these works the elements to the problems raised by this constraint: determination of the magnetic fields intensities to know their calculation and their measurement. Certain spirits also worried about a possible physiological action of the magnetic fields; to appreciate such a possibility, it should be retained that the amplitude of the fields produced by the works of transport energy, on the surface of the ground about (1 to 10 µTesla), i.e. of the same order of magnitude as the earth's magnetic field. We present a calculation programme based on the MATLAB logiciel which makes it possible to better analyze and to represent the transverse profile of the magnetic field under the lines. We also give examp...
IEEE Transactions on Industry Applications, 2015
Advances in Electrical and Computer Engineering, 2007
The aim of this paper is to study the dynamic behaviour of a plant constituted by an electrical p... more The aim of this paper is to study the dynamic behaviour of a plant constituted by an electrical power system and a gas discharge lamp; this latter, increasingly used in street lighting, remains a nonlinear load element. Various approaches are used to represent it, one is the approximation of the discharge represented by a hot "channel", which verifies the assumption of local thermodynamic equilibrium [LTE] or the polynomial form of the conductance variation. A calculation procedure, based on "channel" approximation of the high pressure mercury (HPM) gas-discharge lamp, is developed to determine the physical and electric magnitudes, which characterize the dynamic behavior of the couple "lampelectrical power system". The evolution of the lamp properties when principal parameters of the discharge (pressure of mercury, voltage supply, frequency) are varying were studied and analyzed. We show the concordance between simulation, calculations and measurements for electric, energetic or irradiative characteristics. The model reproduces well the evolution of properties of the supply when principal parameters of the discharge vary.
IEEE Transactions on Dielectrics and Electrical Insulation, 2013
A cyclone can be employed as tribocharging device for free-fall electrostatic separation of granu... more A cyclone can be employed as tribocharging device for free-fall electrostatic separation of granular plastic mixtures. The objective of this work is to validate the possibility of modifying the "standard" operation of such a device, so that the turbine of the cyclone to participate in the charging process of the granules. Thus the granular product is introduced through a funnel into the turbine and then blown into the cyclone. When processed independently in the cyclone tribocharger, the charge acquired by the granules is significantly higher than in a fluidized bed device. On the contrary. when mixtures of granules are introduced into the tribocharger, the electrostatic separation efficiency is lower than with the latter device. However, the efficiency of the triboelectrostatic separation increases when covering the inner wall of the cyclone with a material that is located in the triboelectric series in-between the plastics to be sorted. as an Invited Scientist, to work on a joint research project on new electrostatic separation technologies. His other fields of interest are high voltage insulation and gas discharges. He is vice-chair of IEEE -Algeria Subsection.
IEEE Transactions on Dielectrics and Electrical Insulation, 2013
ABSTRACT The tribo-aero-electrostatic separator achieves the selective sorting of mixed granular ... more ABSTRACT The 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.
2014 IEEE Industry Application Society Annual Meeting, 2014
2011 IEEE Industry Applications Society Annual Meeting, 2011
ABSTRACT Mixed granular insulating materials can be electro-statically separated by tribocharging... more ABSTRACT Mixed granular insulating materials can be electro-statically separated by tribocharging them 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 evaluate the effect of ambient air humidity on the outcome of this tribo-aero-electrostatic separation process, i.e. the mass of the granules collected at the two electrodes that generate the electric field. The mixture to be separated was composed of Acrylonitrile Butadiene Styrene (ABS) and High Impact Polystyrene (HIPS) originating from the recycling of waste electric and electronic equipment. A set of experiments carried out for two durations (30 s and 60 s), at two values of ambient relative humidity (RH = 20% and RH = 40%), pointed out that the separation becomes efficient beyond a certain value of the initial mass of the mixtures. The experimental design methodology and commercial software MODDE 5.0 were then employed for investigating the effects of two process variables: the speed of the metallic conveyors that serve as high-voltage electrodes, and the humidity of ambient air. The effectiveness of separation was found to depend significantly on the latter factor. Surface potential decay measurements performed on charged layers of the two sorts of particles facilitate the interpretation of separation results: at higher RH, the hydrophilic ABS granules loose faster their charge when in contact with a grounded plate. As a consequence, they are in less number than the HIPS granules to be collected at the exit of the tribo-aero-electrostatic separation chamber.
2014 IEEE Industry Application Society Annual Meeting, 2014
2014 IEEE Industry Application Society Annual Meeting, 2014
2013 IEEE Industry Applications Society Annual Meeting, 2013
ABSTRACT This work presents a comprehensive study of an electrostatic separation device for the r... more ABSTRACT This work presents a comprehensive study of an electrostatic separation device for the recycling of granular plastic materials from waste electrical and electronic equipment (WEEE). The peculiarity of this system is the association of two charging techniques: (i) fluidized bed and (ii) sliding on inclined plates, and two superposed separation units, in order to achieve the selective sorting of a granular mixture composed of three different species of insulating materials. The tests were performed on a mixture of high density polyethylene (HDPE), polyvinyl chloride (PVC) and polycarbonate (PC). A set of tribocharging experiments was conducted for each material, so that to choose the nature of the walls of the static charger. The analysis of the purity of separated products was performed using an image processing program written in MATLAB. High purity separation (85%, 95% and 75% for the PVC, PC and HDPE products, respectively) was obtained at a recovery rate beyond 80%.
2013 IEEE Industry Applications Society Annual Meeting, 2013
ABSTRACT New electrostatic separation processes have been developed for the treatment of waste el... more ABSTRACT New electrostatic separation processes have been developed for the treatment of waste electrical and electronic equipment (WEEE), the amounts of which are increasing from year to year. The objective of this paper is to analyze two possibilities for improving the performance of a semi-industrial tribo-aero-electrostatic separator for insulating granules: decrease the section or modify the wall material of the fluidized bed. The electric field of the separator is generated between two metallic belt conveyors connected to two DC high voltage supplies of opposite polarities and is orthogonal to the direction of the fluidized air. The experiments were performed on a insulating granular mixture consisting of acrylonitrile-butadiene-styrene (ABS) and high impact polystyrene (HIPS), average size 2 mm, originating from the processing of WEEE. The first series of experiments was conducted for two sections of the fluidized bed (42 cm × 15 cm and 30 cm × 15 cm, respectively) in similar environmental conditions (temperature: 18 ° C, relative humidity: 40% ± 1). The decrease of the surface of the fluid bed was accompanied by an increase in the mass of products recovered in the collecting boxes: 52% for ABS and over 14% for HIPS. The second series of tests demonstrated the role of the lateral walls of the fluidized bed. The walls of polymethyl metracrylate-(PMMA) promote the separation of ABS, while those in acetate improve the recovery of HIPS.
2008 IEEE Industry Applications Society Annual Meeting, 2008
ABSTRACT In the case of the complex multi-factorial processes, such as electrostatic separation o... more ABSTRACT In the case of the complex multi-factorial processes, such as electrostatic separation of granular materials, the variability of the results is often deplored by the users. Attempts have been made to independently supervise each factor by using Shewhart control charts, which proved to be not very effective in detecting small shifts in process response. The present paper aimed at demonstrating that the effectiveness of the statistic process control can be improved by using CUSUM (cumulative sum) charts. The experiments were carried out with a mixture of bronze and aluminum particles (size range: 1 to 2 mm), using a plate-type electrostatic separator. The mobile average Shewart and CUSUM charts were established, based on 20 electrostatic separation tests performed under optimal operating conditions. An out-of-control situation was simulated and the response of the process was analyzed with both types of charts. The small shift in process response was detected only on the CUSUM chart.
IEEE Industry Applications Magazine, 2000
HE AIM OF THIS article is to point out the characteristics of Shewhart and CUSUM charts when appl... more HE AIM OF THIS article is to point out the characteristics of Shewhart and CUSUM charts when applied to electrostatic separation processes and validate their ability to detect special events that may be indicators of out-of-control situations. This article also shows how the effectiveness of statistical process control (SPC) can be improved by using the cumulative sum (CUSUM) chart. Experiments were carried out with a mixture of bronze and aluminum particles (size range: 1-2 mm) by using a platetype electrostatic separator. The mobile-average Shewhart and CUSUM charts were established based on 20 electrostatic separation tests performed under optimal operating conditions. An out-of-control situation was simulated, and the response of the process was
2015 IEEE Industry Applications Society Annual Meeting, 2015
The principal objective of this paper is to present a determination calculation program of the ex... more The principal objective of this paper is to present a determination calculation program of the exact profile of the level of radionoise of existing lines E.H.V and on project according to the frequency. The method used for the determination of the disturbing field is an analytical method based on the theory of the modal propagation.
IEEE Transactions on Industry Applications, 2015
ABSTRACT The two- conveyor-electrodes tribo- aero- electrostatic separator is a device patented i... more ABSTRACT The two- conveyor-electrodes tribo- aero- electrostatic separator is a device patented in 2010 and intended to sort granular mixtures of insulating materials in a fluidized bed affected by an electric field perpendicular to the direction of the fluidizing air. The prototype of the device has proven its efficiency for the separation of insulating granules of size less than or equal to 2 mm, attaining excellent recovery rates. Unfortunately, its performances were less satisfactory for larger particles (2 to 4.5 mm). The objective of this work is to propose three modifications of the construction of this device, in order to increase the hourly throughput and improve the purity of the separated products. A primary analysis shows that the designer of the equipment can act on two factors namely the charge Q acquired by the granules and the electric field intensity E. Numerical simulations enabled the optimization of the electric field distribution in the active zone of the separator and an experimental study was carried out in order to identify the best conditions for particle charging by triboelectric effect. The tests were carried out for four configurations of the electrode system, by using a mixture of acrylonitrile butadiene styrene (ABS) and high impact polystyrene (HIPS) originated from grinding out-of-use computer cases. The typical granule size was of the order of 2 to 4.5 mm. The experimental approach validated a change in the position of the fluidized bed with respect to the conveyor electrodes, to increase the residence time of the granular materials and hence the amount of electric charge acquired by each particle. In order to intensify the electrical field, two solutions were tested and validated: (1) add a grounding electrode in the proximity of the high-voltage electrodes; (2) dispose vertically the high voltage electrodes. For the tested materials, the vertical arrangement of the electrodes gave the best hourly throughput rates and purity of the separated products.
Le but de cet article est de présenter une méthode à utiliser dans la détermination du point opti... more Le but de cet article est de présenter une méthode à utiliser dans la détermination du point optimal de fonctionnement d’un séparateur électrostatique de matériaux granulaires. La méthode consiste dans l’application des plans d’expériences afin de déterminer les paramètres du processus. Le logiciel MODDE 5.0 à été utilisé pour ce but.
When designing line of electric power transport, it is necessary to dimension these installations... more When designing line of electric power transport, it is necessary to dimension these installations according to the high magnetic fields. This present paper gives a method to calculate and represent the magnetic field around a three-phase line; it proposes to bring to the owner of these works the elements to the problems raised by this constraint: determination of the magnetic fields intensities to know their calculation and their measurement. Certain spirits also worried about a possible physiological action of the magnetic fields; to appreciate such a possibility, it should be retained that the amplitude of the fields produced by the works of transport energy, on the surface of the ground about (1 to 10 µTesla), i.e. of the same order of magnitude as the earth's magnetic field. We present a calculation programme based on the MATLAB logiciel which makes it possible to better analyze and to represent the transverse profile of the magnetic field under the lines. We also give examp...
IEEE Transactions on Industry Applications, 2015
Advances in Electrical and Computer Engineering, 2007
The aim of this paper is to study the dynamic behaviour of a plant constituted by an electrical p... more The aim of this paper is to study the dynamic behaviour of a plant constituted by an electrical power system and a gas discharge lamp; this latter, increasingly used in street lighting, remains a nonlinear load element. Various approaches are used to represent it, one is the approximation of the discharge represented by a hot "channel", which verifies the assumption of local thermodynamic equilibrium [LTE] or the polynomial form of the conductance variation. A calculation procedure, based on "channel" approximation of the high pressure mercury (HPM) gas-discharge lamp, is developed to determine the physical and electric magnitudes, which characterize the dynamic behavior of the couple "lampelectrical power system". The evolution of the lamp properties when principal parameters of the discharge (pressure of mercury, voltage supply, frequency) are varying were studied and analyzed. We show the concordance between simulation, calculations and measurements for electric, energetic or irradiative characteristics. The model reproduces well the evolution of properties of the supply when principal parameters of the discharge vary.
IEEE Transactions on Dielectrics and Electrical Insulation, 2013
A cyclone can be employed as tribocharging device for free-fall electrostatic separation of granu... more A cyclone can be employed as tribocharging device for free-fall electrostatic separation of granular plastic mixtures. The objective of this work is to validate the possibility of modifying the "standard" operation of such a device, so that the turbine of the cyclone to participate in the charging process of the granules. Thus the granular product is introduced through a funnel into the turbine and then blown into the cyclone. When processed independently in the cyclone tribocharger, the charge acquired by the granules is significantly higher than in a fluidized bed device. On the contrary. when mixtures of granules are introduced into the tribocharger, the electrostatic separation efficiency is lower than with the latter device. However, the efficiency of the triboelectrostatic separation increases when covering the inner wall of the cyclone with a material that is located in the triboelectric series in-between the plastics to be sorted. as an Invited Scientist, to work on a joint research project on new electrostatic separation technologies. His other fields of interest are high voltage insulation and gas discharges. He is vice-chair of IEEE -Algeria Subsection.
IEEE Transactions on Dielectrics and Electrical Insulation, 2013
ABSTRACT The tribo-aero-electrostatic separator achieves the selective sorting of mixed granular ... more ABSTRACT The 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.
2014 IEEE Industry Application Society Annual Meeting, 2014
2011 IEEE Industry Applications Society Annual Meeting, 2011
ABSTRACT Mixed granular insulating materials can be electro-statically separated by tribocharging... more ABSTRACT Mixed granular insulating materials can be electro-statically separated by tribocharging them 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 evaluate the effect of ambient air humidity on the outcome of this tribo-aero-electrostatic separation process, i.e. the mass of the granules collected at the two electrodes that generate the electric field. The mixture to be separated was composed of Acrylonitrile Butadiene Styrene (ABS) and High Impact Polystyrene (HIPS) originating from the recycling of waste electric and electronic equipment. A set of experiments carried out for two durations (30 s and 60 s), at two values of ambient relative humidity (RH = 20% and RH = 40%), pointed out that the separation becomes efficient beyond a certain value of the initial mass of the mixtures. The experimental design methodology and commercial software MODDE 5.0 were then employed for investigating the effects of two process variables: the speed of the metallic conveyors that serve as high-voltage electrodes, and the humidity of ambient air. The effectiveness of separation was found to depend significantly on the latter factor. Surface potential decay measurements performed on charged layers of the two sorts of particles facilitate the interpretation of separation results: at higher RH, the hydrophilic ABS granules loose faster their charge when in contact with a grounded plate. As a consequence, they are in less number than the HIPS granules to be collected at the exit of the tribo-aero-electrostatic separation chamber.
2014 IEEE Industry Application Society Annual Meeting, 2014
2014 IEEE Industry Application Society Annual Meeting, 2014
2013 IEEE Industry Applications Society Annual Meeting, 2013
ABSTRACT This work presents a comprehensive study of an electrostatic separation device for the r... more ABSTRACT This work presents a comprehensive study of an electrostatic separation device for the recycling of granular plastic materials from waste electrical and electronic equipment (WEEE). The peculiarity of this system is the association of two charging techniques: (i) fluidized bed and (ii) sliding on inclined plates, and two superposed separation units, in order to achieve the selective sorting of a granular mixture composed of three different species of insulating materials. The tests were performed on a mixture of high density polyethylene (HDPE), polyvinyl chloride (PVC) and polycarbonate (PC). A set of tribocharging experiments was conducted for each material, so that to choose the nature of the walls of the static charger. The analysis of the purity of separated products was performed using an image processing program written in MATLAB. High purity separation (85%, 95% and 75% for the PVC, PC and HDPE products, respectively) was obtained at a recovery rate beyond 80%.
2013 IEEE Industry Applications Society Annual Meeting, 2013
ABSTRACT New electrostatic separation processes have been developed for the treatment of waste el... more ABSTRACT New electrostatic separation processes have been developed for the treatment of waste electrical and electronic equipment (WEEE), the amounts of which are increasing from year to year. The objective of this paper is to analyze two possibilities for improving the performance of a semi-industrial tribo-aero-electrostatic separator for insulating granules: decrease the section or modify the wall material of the fluidized bed. The electric field of the separator is generated between two metallic belt conveyors connected to two DC high voltage supplies of opposite polarities and is orthogonal to the direction of the fluidized air. The experiments were performed on a insulating granular mixture consisting of acrylonitrile-butadiene-styrene (ABS) and high impact polystyrene (HIPS), average size 2 mm, originating from the processing of WEEE. The first series of experiments was conducted for two sections of the fluidized bed (42 cm × 15 cm and 30 cm × 15 cm, respectively) in similar environmental conditions (temperature: 18 ° C, relative humidity: 40% ± 1). The decrease of the surface of the fluid bed was accompanied by an increase in the mass of products recovered in the collecting boxes: 52% for ABS and over 14% for HIPS. The second series of tests demonstrated the role of the lateral walls of the fluidized bed. The walls of polymethyl metracrylate-(PMMA) promote the separation of ABS, while those in acetate improve the recovery of HIPS.
2008 IEEE Industry Applications Society Annual Meeting, 2008
ABSTRACT In the case of the complex multi-factorial processes, such as electrostatic separation o... more ABSTRACT In the case of the complex multi-factorial processes, such as electrostatic separation of granular materials, the variability of the results is often deplored by the users. Attempts have been made to independently supervise each factor by using Shewhart control charts, which proved to be not very effective in detecting small shifts in process response. The present paper aimed at demonstrating that the effectiveness of the statistic process control can be improved by using CUSUM (cumulative sum) charts. The experiments were carried out with a mixture of bronze and aluminum particles (size range: 1 to 2 mm), using a plate-type electrostatic separator. The mobile average Shewart and CUSUM charts were established, based on 20 electrostatic separation tests performed under optimal operating conditions. An out-of-control situation was simulated and the response of the process was analyzed with both types of charts. The small shift in process response was detected only on the CUSUM chart.