ensor fault detection and isolation for smart irrigation wireless sensor network based on parity space

In the recent years, wireless sensor network technology (WSN) has been widelyadopted in precision agriculture for determining the needs of the soil in termof water by monitoring some environmental parameters. To do this, WSN isconstructed using several sensor nodes; these small sensing devices are prone tofailure and may produce erroneous measurements. To ensure good managementof freshwater, the network service quality is necessary. To avoid the degradationof service, the detection of the faulty sensor in WSN is required. In this paper,a fault detection and isolation (FDI) algorithm derived from a parity space approachand based on direct redundancy is proposed toward detecting and isolatingsensor fault in WSN. In laboratory experiments, the proposed FDI algorithmproved its effectiveness

Hybrid electrode obtained by sol-gel derived Ni0.3Co2.7O4 nanoparticles incorporated into polypyrrole: Electrocatalysis of O2 reduction

A hybrid electrode was formed on glassy carbon (GC) electrode with polypyrrole (PPy) and mixed valence Ni0.3Co2.7O4 nanoparticles to study their behaviour towards the oxygen reduction reaction (ORR). The oxide nanoparticles were prepared by sol-gel route using various parameters and characterized by XRD, SEM, EDX and BET methods. The result showed that desired oxide was obtained and nanocrystallites exhibit a specific surface area ranging from 39 to 73 m2/g with diameter varying from 13 to 25 nm. The hybrid electrode was then fabricated by electropolymerization of pyrrole (Py) in the presence of the smallest Ni0.3Co2.7O4 nanoparticles in KCl (0.15 mol/L) at room temperature and characterized by EDX, SEM and LSV methods. Investigation of the hybrid electrode confirmed that O2 reduction mechanism changes by applying potential. Thus, at low overpotential the O2 reduction involves two electrons and provides H2O2, with cathodic transfer coefficients (β) of 0.33 and exchange current density ( j0) of about 8×10-3 mA/cm2, while, at high overpotential H2O2 is further reduced into H2O. The results also show that sol-gel method led to the preparation of Ni0.3Co2.7O4 nanoparticles having a spinel structure with a desired stoichiometry which exhibits a high electrocatalytic activity for reducing oxygen mostly to H2O2

Kalman filter based sensor fault detection in wireless sensor network for smart irrigation

Ensuring the reliability of data obtained from Wireless Sensor Networks (WSNs) deployed in farmland to monitor soil parameters is crucial for optimizing smart irrigation. These distributed sensor nodes encounter various challenges and are vulnerable to sensor faults that can significantly degrade the network's service quality. In this article, we present an innovative approach for detecting sensor faults within WSNs for smart irrigation by combining an autoregressive model with a Kalman filter. Integrating the Kalman filter and the autoregressive model combines their strengths in a synergistic manner. The algorithm is developed with consideration for the resource constraints of the sensor nodes and addresses the challenge of lacking ground truth information for the monitored area. The primary advantage of this proposed technique lies in its simplicity of implementation, requiring minimal computational complexity while enhancing the application's reliability. Through experimentation and validation, we demonstrate the effectiveness of this combined approach in detecting sensor fault detection in real-world WSNs scenarios

Characterization of Thin Anodically Grown Oxide Films on AISI 304L Stainless Steel

International audienceThe passivity and protective nature of the passive films are essentially related to ionic and electronic transport processes, which are controlled by the optical and electronic properties of passive films. Corrosion properties of passive films anodically formed on 304L stainless steel in borate/boric acid solution have been examined using electrochemical impedance spectroscopy (EIS). An electrical equivalent circuit based on the impedance analysis, which describes the behavior of the passive film on stainless steel more satisfactorily than the proposed models, is presented. The semiconducting properties of the passive films were also investigated by photoelectrochemistry. Effects of film-formation potential, film-formation time, and applied potential on the electronic properties were studied. Depending on the operating conditions, the optical bandgap values were estimated to vary from 2.1 to 2.75 eV. Both film resistance and bandgap were found to decrease with applied potential. Therefore, correlation between the two significant parameters was determined

Magnetic properties and giant magnetoresistance in electrodeposited Co?Ag granular films

International audienceSmall cobalt particles embedded in a silver matrix have been prepared using the electrodeposition technique. The size of the clusters is controlled by the deposition potential and the Co growth time. Structural, magnetic and magneto-transport properties of Co–Ag samples have been investigated as a function of the Co concentration between 2 and 40 at% cobalt. Superparamagnetic behavior is evidenced for the low contents of cobalt while long-range magnetic order appears at higher Co concentrations. The particles size has been determined from magnetic properties and from the X-ray diffraction technique, and varies between 3.5 and 9 nm. Magnetoresistance passes through a maximum as a function of the cobalt concentration. A maximum of ~ 4% GMR is obtained at room temperature while GMR reaches a value of 14% at 10 K

Highly broadband plasmonic Cu film modified Cu2O/TiO2 nanotube arrays for efficient photocatalytic performance

International audienceTo develop an efficient photocatalyst electrode for solar energy harvesting and photocatalysis application in the visible region, broadband plasmonic Cu film combined with Cu2O/TiO2 nanotube arrays heterojunction (Cu film/Cu2O/TiNT) has been successfully fabricated by anodization combined with electrodeposition method. Interestingly, linear sweep voltammetry (LSV), electrochemical impedance spectroscopy (EIS) and UV–Vis diffuse reflectance spectroscopy reveal that the combined consequence of both Cu film and Cu2O in the as-synthesized ternary composite considerably enhances light absorption in the visible spectral. This activity is attributed to the more efficient charge separation/transportation and the presence of Cu film with strong plasmon resonance (SPR) effect. Moreover, the combined effects of both Cu film and Cu2O on TiNT approved highest catalytic current density and highest photocatalytic activity on methylene blue (MB). The efficiency and the rate of MB photodegradation over the Cu film/Cu2O/TiNT were found to be triple compared to TiNT. Within only 30 min of reaction time, the photodegradation of MB reaches nearly 100%

Electrochemical Impedance Investigation of Anodic Alumina Barrier Layer

International audienceIn the present work, well ordered nanoporous anodic aluminum oxides (AAO) have been prepared on aluminum by a two step anodization process in 0.5 M oxalic acid at various potentials. We report the properties and semiconducting characteristics of the porous alumina barrier layers by electrochemical impedance spectroscopy analysis (EIS). EIS is considered to be a highly sensitive and non-destructive technique that allows determining barrier oxide layer characteristics. Aluminum oxide barrier is considered as a semiconductor which acts as a p-n heterojunction at anodizing voltages up to 20 V. The alumina barrier layer structure consists of a hole transport inner layer and an electron transport outer layer. Doping densities, flatband potential as well as space charge layer thickness are discussed in correlation with anodizing potential. Barrier layer thicknesses measurements obtained by EIS were compared with those obtained after EIS measurements by direct scanning electron microscopy observations

Artemisia Herba Alba Essential Oil as Green Corrosion Inhibitor for Aluminum in Hydrochloric Acid Solution

International audienceArtemisia herba-alba essential oil extract was investigated as green inhibitor for aluminum corrosion in 1 M HCl solution. The chemical analysis obtained by gas chromatography and gas chromatography-mass spectrometry, revealed 68 components. The inhibition efficiency was determined by weight loss measurements, potentiodynamic polarization, electrochemical impedance spectroscopy and scanning electron microscope. The results revealed an increase of inhibition efficiency by maximum 92% trough increasing the oil concentration to 3 g/L at 333 K. The oil compounds adsorb by physisorption, follow Langmuir adsorption isotherm and act as mixed type inhibitors. The EIS results confirmed the adsorption mechanism process and the SEM observations

Manganese and bismuth electrodeposition from a choline chloride based deep eutectic solvents

International audienceThe effect of different additives on manganese and bismuth electrodeposition from choline chloride-urea(Reline) and choline chloride-ethylene glycol (Ethaline) deep eutectic solvents (DESs) was investigated. Spectroscopic and thermal studies were performed on the latters in order to understand whether some additives affect the DESs behaviors. the results of the thermal study do not indicate any significant change except a small shift in the melting point of the reline when adding ammonium chloride (~+3°C) and the modification of a cold crystallization peaks at low scan rate. The electrochemical behaviors of manganese and bismuth were then studied by cyclic voltammetry. electrocrystallization was studied by chronoamperometry which has shown that the bismuth electrodeposition evolves with a 3D progressive nucleation. The current transients for Mn reveals that the presence of thiourea enhances the nucleation rate by modifying the corresponding nucleation and growth model from 3D progressive to 3D instantaneous. EDS analysis confirms that pure bismuth thin films were obtained and X-Ray diffraction indicates that the bismuth growth follows a preferential orientation along the (012) reticular plane. While for manganese, no metal phase was observed in diffraction due to the amorphous nature of Mn deposits. Annealing treatments will therefore be necessary

Ammonium chloride effects on bismuth electrodeposition in a choline chloride-urea deep eutectic solvent

International audienceThe ammonium chloride effect on bismuth electrodeposition from choline chloride-urea deep eutectic solvent (DES) was investigated. Spectroscopic and thermal studies were performed on the latter in order to understand whether the addition of ammonium chloride affects the DES behavior; the results of the thermal study do not indicate any significant change except a small shift in the melting point of the DES when adding the ammonium salt (~+3 °C) and the modification of a cold crystallization peaks at low scan rate. The electrochemical behavior of bismuth was then studied by cyclic voltammetry in the deep eutectic solvent with different NH4Cl content. Bismuth electrocrystallization was studied by chronoamperometry which has shown that the bismuth electrodeposition in studied conditions evolves with a three-dimensional progressive nucleation. SEM images show that grain size of bismuth deposits decreases while adopting a well-defined geometry as ammonium salt concentration increases. EDS analysis confirms that pure bismuth thin films were obtained and X-Ray diffraction indicates that the bismuth growth follows a preferential orientation along the (012) reticular plane