No-chatter model-free sliding mode control for synchronization of chaotic fractional-order systems with application in image encryption

Multimedia Tools and Applications - Synchronization of different Chaotic dynamical systems is one of the main issues in engineering which has a lot of applications in applied sciences like secure...     

Antimicrobial Property,Antioxidant Capacity,and Cytotoxicity of Essential Oil from Cumin Produced in Iran

ABSTRACT: Cumin (Cuminum cyminum) is one of the commonly used spices in food preparations. It is also used in traditional medicine as a stimulant, a carminative, and an astringent. In this study, we characterized the antimicrobial, antioxidant, and cytotoxic activities of cumin. E. coli, S. aureus, and S. faecalis were sensitive to various oil dilutions. The total phenol content of the essential oil was estimated to be 33.43 μg GAE/mg of the oil. The oil showed higher antioxidant activity compared with that of BHT and BHA. The cumin essential oil exhibited a dose-dependent scavenging of DPPH radicals and 5.4 μg of the oil was sufficient to scavenge 50% of DPPH radicals/mL. At a concentration of 0.1 μL/mL, oil destructed Hela cells by 79%. The antioxidant activity of cumin essential oil might contribute to its cytotoxic activity. Acute and subchronic toxicity was studied in a 30-d oral toxicity study by administration to Wistar rats of the essential oil. A 17.38% decrease in WBCs count, and 25.77%, 14.24%, and 108.81% increase in hemoglobin concentration, hematocrit, and platelet count, respectively, were noted. LDL/HDL ratio was reduced to half, which adds to the nutritional effects of cumin. Thus, cumin with a high phenolic content and good antioxidant activity can be supplemented for both nutritional purposes and preservation of foods.     

Cr2O3 nanoparticles: A promising candidate to improve the mechanical properties and corrosion resistance of Ni-Co alloy coatings

This study was aimed to assess the effects of reinforcement nanoparticles content, on the microstructural features, mechanical properties, and corrosion-related properties of Ni-Co-Cr₂O₃ nanocomposite coatings. Scanning electron microscope (SEM), energy dispersive X-ray spectrometer (EDS), and X-ray diffraction (XRD) analysis were employed in order to evaluate the microstructural features and chemical composition of the nanocomposites. Moreover, the microhardness tester and electrochemical impedance spectra (EIS) tests coupled with potentiodynamic polarization measurements were used to investigate the mechanical and corrosion-related properties, respectively. Results demonstrate that albeit the volume fraction of cobalt in coating, average particle size, Cr₂O₃ nanoparticle content in coating, and microstructural features are of prime significance in determining the mentioned properties of the nanocomposite coatings, Co content is more important. Actually, Cr₂O₃ nanoparticles serve as suitable nucleation sites for Co particles deposition throughout the microstructure. Thus, combined actions of Cr₂O₃ nanoparticles incorporation and their optimal content ensures the nucleation of high population of Co particles, which significantly contributes to the improvement in the properties. The Ni-Co-8.9 wt%Cr₂O₃ nanocomposite coating exhibits the superior mechanical and corrosion-related properties.     

Modeling of thermodynamic properties of carrot product using ALO,GWO, and WOA algorithms under multi-stage semi-industrial continuous belt dryer

Engineering with Computers - In this paper, multi-stage continuous belt (MSCB) dryer was used for carrot slices drying. Experiments were performed at three air speeds (1, 1.5, and 2 m/s)...     

Preparation of Pulse Electrodeposited Ni-B Coating with RSM Software and Evaluation of Its Microhardness and Electrochemical Behavior

Metallurgical and Materials Transactions A - In this study, the electrodeposition parameters were optimized to attain Ni-B alloy coatings with high hardness and corrosion resistance. The optimum...     

Self-consistent performance modeling for dual band MIS UV photodetectors based on Si/SiO2 multilayer structure

In this paper, we present a self-consistent theoretical model for a metal-insulator semiconductor (MIS) dual band ultraviolet (UV) photodetector with a modified structure implying an arbitrarily defined insulating potential barrier as its active region. Utilizing our proposed model, the dark and photocurrent density-voltage (J-V) characteristics of MIS UV photodetectors with multi-quantum wells of silicon (MQWs) are calculated. We demonstrate that dark current is reduced in the suggested structure, because the electron-tunneling probability becomes unity at energies coincident with the peak detection wavelength. This is due to the resonant tunneling and decreases at energies that are significantly smaller than this optimum value. In consequence, the number of carriers contributing to the dark current, which have a broad energy distribution at high temperatures, will decrease. It is also shown that the designed structure could detect two individual UV wavelengths, simultaneously. The width of each Si quantum well has been considered at around 1.2 nm, in order to observe these two absorption peaks in the middle and near UV regions of photon spectrum (about 365 nm, 175 nm).     

Depression of pyrite in the flotation of high pyrite low-grade lead–zinc ore using Acidithiobacillus ferrooxidans

In this research work, selective depression of pyrite in the flotation of a low-grade lead–zinc ore containing 31% pyrite was investigated in the absence and presence of Acidithiobacillus ferrooxidans. Pyrite was significantly depressed with these bacteria using the optimum dosage of reagents. Sphalerite recovery and Zn grade in the obtained sphalerite concentrate were both enhanced by bacteria. The results of bioflotation experiments showed that bacterial depression of pyrite is very sensitive to the concentration of other flotation reagents. Least significance difference (LSD) bars were used to study the significance of the factors under study with a confidence interval of 90%. Under similar conditions, A. ferrooxidans was seen to increase the Zn grade and separation efficiency more effectively than sodium cyanide. Flotation kinetic studies confirmed a considerable decrease in the pyrite kinetic rate constant in the presence of A. ferrooxidans.     

A novel proposal for ultra-high optical nonlinearity in GaN/AlGaN spherical centered defect quantum dot (SCDQD)

In this paper a novel idea for enhancement and tunable optical nonlinearity based on spherical centered defect quantum dot (SCDQD) is proposed. The proposed structure is a special quantum dot including a spherical defect inside it. Complete analysis of the proposed structure based on the effective mass equation is done and optical properties (third-order susceptibilities of quadratic electro-optic effect (QEOE) and third harmonic generation (THG) associated with intersubband transition) of the introduced structure using density matrix method are investigated also. Effects of system parameters including defect and dot on energy levels and optical nonlinearity are examined. We observed that the proposed structure has high nonlinear and tunable susceptibilities suitable for implementation of optical active and passive devices. It is shown that the magnitudes of dipole transition matrix element, third-order susceptibilities of THG and QEOE can be increased significantly compared traditional cases (4.5-10 nm, 10⁻¹¹-10⁻⁹ m²/V² and 10⁻¹²-10⁻⁹ m²/V², respectively). Also, the resonance wavelengths are displaced using these parameters that can be used for realization of tunable devices.