Automatic condition monitoring of electromechanical system based on MCSA, spectral kurtosis and SOM neural network

Condition monitoring and fault diagnosis play the most important role in industrial applications. The gearbox system is an essential component of mechanical system in fault identification and classification domains. In this paper, we propose a new technique which is based on the Fast-Kurtogram method and Self Organizing Map (SOM) neural network to automatically diagnose two localized gear tooth faults: a pitting and a crack. These faults could have very different diagnostics; however, the existing diagnostic techniques only indicate the presence of local tooth faults without being able to differentiate between a pitting and a crack. With the aim to automatically diagnose these two faults, a dynamic model of an electromechanical system which is a simple stage gearbox with and without defect driven by a three phase induction machine is proposed, which makes it possible to simulate the effect of pitting and crack faults on the induction stator current signal. The simulated motor current signal is then analyzed by using a Fast-Kurtogram method. Self-organizing map (SOM) neural network is subsequently used to develop an automatic diagnostic system. This method is suitable for differentiating between a pitting and a crack fault

Automatic condition monitoring of electromechanical system based on MCSA, spectral kurtosis and SOM neural network

Condition monitoring and fault diagnosis play the most important role in industrial applications. The gearbox system is an essential component of mechanical system in fault identification and classification domains. In this paper, we propose a new technique which is based on the Fast-Kurtogram method and Self Organizing Map (SOM) neural network to automatically diagnose two localized gear tooth faults: a pitting and a crack. These faults could have very different diagnostics; however, the existing diagnostic techniques only indicate the presence of local tooth faults without being able to differentiate between a pitting and a crack. With the aim to automatically diagnose these two faults, a dynamic model of an electromechanical system which is a simple stage gearbox with and without defect driven by a three phase induction machine is proposed, which makes it possible to simulate the effect of pitting and crack faults on the induction stator current signal. The simulated motor current signal is then analyzed by using a Fast-Kurtogram method. Self-organizing map (SOM) neural network is subsequently used to develop an automatic diagnostic system. This method is suitable for differentiating between a pitting and a crack fault

Gyro-Chirality Effect of Bianisotropic Substrate On the operational of Rectangular Microstrip Patch Antenna

yesIn this paper, the gyrotropic bi-anisotropy of the chiral medium in substrate constitutive parameters (ξc and ηc) of a rectangular microstrip patch antenna is introduced in order to observe its effects on the complex resonant frequency, half-power bandwidth and input impedance. Numerical calculations and analysis based on the dominant mode are carried out to show that the latter is directly related to the former. This paper is based on the Moment Method as full-wave spectral domain approach using sinusoidal basis functions. Two new results, namely the appearance of the difference (ξc-ηc) and sum (ξc+ηc) of the two magneto-electric elements are obtained in the electric transverse components and Green tensor expressions, respectively. These new results can be considered as a generalisation form of the previously published work

Horn Antennas Loaded with Metamaterial for UWB Applications

YesIn this paper, a conical horn antenna has been designed for Ultra-Wideband ap-plications by loading its section with a metamaterial. The work aims first to compare results obtained by the wavelet-moment method to a simulation performed using HFSS. Secondly the conical horn is loaded with a very thin layer of metamaterial to enhance the radiation pattern and the bandwidth performance of the conical horn antenna and reduce the size of the antenna. The operating bandwidth of the proposed antenna is in the range of 10{13 GHz. The results obtained from HFSS and moment method are in good agreement.Electronics and Telecommunication

Theoretical Study of the Input Impedance and Electromagnetic Field Distribution of a Dipole Antenna Printed on an Electrical/Magnetic Uniaxial Anisotropic Substrate

The present work considers the investigation of the effects of both electrical and magnetic uniaxial anisotropies on the input impedance, resonant length, and fields distribution of a dipole printed on an anisotropic grounded substrate. In this study, the associated integral equation, based on the derivation of the Green's functions in the spectral domain, is numerically solved employing the method of moments. In order to validate the computing method and the evaluated calculation code, numerical results are compared with available data in the literature treating particular cases of electrical uniaxial anisotropy; reasonable agreements are reported. Novel results of the magnetic uniaxial anisotropy effects on the input impedance and the evaluated electromagnetic field are presented and discussed. This work will serve as a stepping stone for further works for a better understanding of the electromagnetic field behavior in complex anisotropic and bi-anisotropic media

Offset Aperture-Coupled Double-Cylinder Dielectric Resonator Antenna with Extended Wideband

YesA compact dielectric resonator antenna for ultra-wideband vehicular communication applications is proposed. Two cylindrical dielectric resonators are asymmetrically located with respect to the center of an offset rectangular coupling aperture, through which they are fed. Optimizing the design parameters results in an impedance bandwidth of 21%, covering the range from 5.9 to 7.32 GHz in the lower-band and a 53% relative bandwidth from 8.72 to 15 GHz in the upper-band. The maximum achieved gain is 12 dBi. Design details of the proposed antenna and the results of both simulations and experiment are presented and discussed

Wireless Electromagnetic Radiation Assessment Based on the Specific Absorption Rate (SAR): A Review Case Study

Employing Electromagnetic Fields (EMFs) in new wireless communication and sensing technologies has substantially increased the level of human exposure to EMF waves. This paper presents a useful insight into the interaction of electromagnetic fields with biological media that is defined by the heat generation due to induced currents and dielectric loss. The Specific Absorption Rate (SAR) defines the heating amount in a biological medium that is irradiated by an electromagnetic field value. The paper reviews the radio frequency hazards due to the SAR based on various safety standards and organisations, including a detailed investigation of previously published work in terms of modelling and measurements. It also summarizes the most common techniques utilised between 1978 and 2021, in terms of the operational frequency spectrum, bandwidth, and SAR values

Effect of pruning and chemical control on

Introduction In Morocco the olive growers rely totally on pesticides to control the black scale Saissetia oleae, although this technique has adverse effects on natural enemies, on product quality and on the environment. However, the pesticides are not used efficiently because of ignorance of the developmental cycle of the insect, and of the periods of vulnerable instar presence. We studied these two parameters. Next, we tested the efficacy of the pesticide and we studied the effect of pruning on the scales as an alternative to chemicals. Materials and methods The seasonal trend of the black scale was studied in two olive orchards near Essaouira, in the west of Morocco, during 2005 and 2006. One of these orchards was subject to chemical treatment in 2007, while two new orchards were selected to study the effect of pruning on the scales. The evolution of crawler and nymph density on different olive tree organs was followed in order to discover their preferences for these different organs. Results and discussion The seasonal trend study showed the presence of one generation of S. oleae per year and the tendency to colonise young organs rather than old ones. The optimum of mobile instar population coincided with the beginning and the end of July. On the organs of the chemically-treated samples, numbers of crawlers and nymphs were highly reduced. The results showed a small-scale infestation in pruned trees compared with the unpruned trees (control). Conclusion. Though the chemical control has good results, pruning remains very efficient and can help improve the control of the black scale populations without harming the environmen

Surveillance de l'infestation des céréales par la mouche noire (Phorbia securis Tiensu ; Diptera, Anthomyiidae)

A survey of the infestation of cereals by the black fly, Phorbia securis has been reported in Chaouia, Doullala and Abda (Morocco). Its distribution in these different regions is shown in the map. One hundred and seventy seven fields were examined and the black fly was present in all of them. Its number was sufficiently high to be likely to cause a serious damage. The cereals were more attacked in Abda. The larvae attack only ont tiller per plant. The young tillers (14 to 20 cm) were more sensible to the attack.Une surveillance de l’infestation des céréales cultivées par la mouche noire Phorbia securis a eu lieu dans la Chaouia, Doukkala et Abda. Sa distribution dans ces différentes régions est montrée sur la carte. Cent soixante dix sept champs sont examinés et la mouche noire y est présente. Dans 36 champs (20 % des champs infestés), elle a atteint un nombre assez élevé pour être à l’origine de dommage grave. Les céréales sont beaucoup plus attaquées dans la région d’Abda que dans les deux autres régions. La larve n’attaque en général qu’une seule tige par plante. Les tiges de différentes longueurs (de différents âges) ont une susceptibilité d’attaque variable ; celles de 14 à 20 cm de long étant les plus sensibles à l’attaque.Maarouf Abdelkader, Chemseddine Mohamed. Surveillance de l'infestation des céréales par la mouche noire (Phorbia securis Tiensu ; Diptera, Anthomyiidae). In: Ecologia mediterranea, tome 21 n°3-4, 1995. pp. 93-99

La pyrale des dattes dans la région de Tafilalet au Sud-Est du Maroc

Introduction. Diverses espèces de pyrales peuvent s'attaquer aux dattes. Ce ravageur cause jusqu'à 30 % de pertes parmi les récoltes de dattes au Maroc. L'étude présentée a cherché à identifier les espèces de pyrales des dattes et leurs parasitoïdes, en précisant leurs importances relatives, et à dégager les facteurs influençant l'infestation des dattes. Matériel et méthodes. Des prospections ont été menées durant les années 1997 et 1998 dans 16 sites répartis dans les principales palmeraies de la région de Tafilalet. Des échantillonnages ont été effectués sur régimes et sur dattes tombées au sol. Les fruits infestés ont été dénombrés puis placés dans des éclosoirs jusqu'à la sortie des adultes des pyrales et de leurs parasitoïdes. Résultats et discussion. Trois espèces de pyrales peuvent se développer sur les dattes au champ avec des incidences différentes. Le principal ravageur est Ectomyelois ceratoniae. En revanche, Plodia interpunctella et Ephestia figulilella sont des déprédateurs secondaires. L'infestation des dattes varie d'une année à l'autre, les années humides favorisant la pullulation de la pyrale. Les dégâts dus à la pyrale ont varié selon la variété de palmier dattier : la variété Bou feggous à dattes de maturité précoce et à épiderme fin a été la plus vulnérable à l'attaque de la pyrale. L'ensachage des régimes permet de réduire notablement l'infestation des dattes. Les populations d'E. ceratoniae peuvent être également limitées par deux parasitoïdes : Phanerotoma ocuralis sur dattes en régime et Bracon hebetor dans les dattes tombées au sol. Conclusion. L'application de certaines pratiques culturales pourraient aider les agriculteurs à réduire significativement l'infestation des dattes au champ