A New Control Strategy for Photovoltaic System Connected to the Grid via Three-Time-Scale Singular Perturbation Technique with Performance Analysis

This chapter addresses the problem of controlling single-phase grid-connected photovoltaic system through a full bridge inverter with L-filter. The control objectives are threefold: (i) forcing the voltage in the output of photovoltaic panel to track a reference. This reference has been obtained from the maximum power point tracking strategy; (ii) guaranteeing a tight regulation of the DC-link voltage; and (iii) ensuring a satisfactory power factor correction (PFC) at the grid such as the currents injected must be sinusoidal with the same frequency and the same phase as the grid voltage. The considered control problem entails several difficulties including: (i) the high dimension and strong nonlinearity of the system; (ii) the changes in atmospheric conditions. The problem is dealt with by designing a synthesized nonlinear multi-loop controller using singular perturbation technique, in which a three-time-scale dynamics is artificially induced in the closed-loop system. A formal analysis based on the three-time-scale singular perturbation technique and the averaging theory is developed to proved that all control objectives are asymptotically achieved up to small harmonic errors (ripples). The performance of the proposed approach and its strong robustness with respect to climate changes are evaluated based on the various simulations results carried out under Matlab/Simulink software

High-performance FPGA implementation of the secure hash algorithm 3 for single and multi-message processing

The secure hash function has become the default choice for information security, especially in applications that require data storing or manipulation. Consequently, optimized implementations of these functions in terms of Throughput or Area are in high demand. In this work we propose a new conception of the secure hash algorithm 3 (SHA-3), which aim to increase the performance of this function by using pipelining, four types of pipelining are proposed two, three, four, and six pipelining stages. This approach allows us to design data paths of SHA-3 with higher Throughput and higher clock frequencies. The design reaches a maximum Throughput of 102.98 Gbps on Virtex 5 and 115.124 Gbps on Virtex 6 in the case of the 6 stages, for 512 bits output length. Although the utilization of the resource increase with the increase of the number of the cores used in each one of the cases. The proposed designs are coded in very high-speed integrated circuits program (VHSIC) hardware description language (VHDL) and implemented in Xilinx Virtex-5 and Virtex-6 A field-programmable gate array (FPGA) devices and compared to existing FPGA implementations

A HIERARCHICAL REGISTER OPTIMIZATION APPROACH

Abstract A hierarchical register allocation approach in high-level synthesis is presented. First, we accomplish the trivial register allocation and then we attempt to optimize the number of required registers. In this work, we extend conventional register allocation algorithms to handle behavioral descriptions containing conditional branches and loops. However, in our approach the register optimization will carried out with explicit consideration of interconnection cost. Results show that our approach is more efficient for data flow graphs that contain nested conditional blocks and loops

Ayahuasca: proprietà farmacologiche e tossicologiche

Ayahuasca è una bevanda usata nelle tribù indigene del bacino amazzonico durante i riti tribali. E' composta da piante psicoattive, veniva usata come allucinogeno poi si scoprirono le sue potenzialità terapeutiche

Synthesis and investigations of reactive properties, photophysical properties and biological activities of a pyrazole-triazole hybrid molecule

© 2022In this work, we report the synthesis, spectroscopic characterization, reactivity study, photophysical properties and evaluation of α-glucosidase inhibitory activity pyrazole-triazole hybrid molecule. Reactive properties of the title compound have been investigated using density functional theory (DFT) calculations. Local reactive descriptors such as condensed versions of Fukui functions and Molecular electrostatic potential were used to predict the chemical reactivity. Further, the influence of solvents on the photophysical properties was investigated by using Time independent Density Functional Theory (TDDFT) calculations. In addition, the in vitro anti-diabetic activity against α-glucosidase enzyme revealed that the title compound has α-glucosidase inhibitory activity with IC50 value of 43.92 µg/mL. Molecular docking studies were carried out to understand the binding mechanism of the title compound in the active site of the α-glucosidase enzyme. The stability of the protein-ligand complex was validated by Molecular Dynamics (MD) simulations and Molecular Mechanics Poisson-Boltzmann Surface Area (MMPBSA) analysis

Evaluation of In Vitro Antioxidant and Antidiabetic Activities of Aristolochia longa Extracts

Oxidative stress plays a major role in diabetic physiopathology; hence, the interest of using natural antioxidants as therapeutic tools exists. The aim of this study was the evaluation of in vitro antioxidant activity and inhibitory potential of organic extracts from Aristolochia longa roots against key enzymes linked to hyperglycemia. Antioxidant activity was performed using 2,2′-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azino-bis-3-ethylbenzothiazoline-6-sulfonic acid (ABTS) radicals and ferric reducing/antioxidant power (FRAP) methods. The α-Glucosidase and β-Galactosidase inhibitory activities were investigated using an in vitro model. Moreover, phytochemical analysis of tested extracts was carried out. The aqueous fraction of this herb exhibited the highest antioxidant activity for both DPPH and ABTS methods, IC50=125.40±2.40 μg/mL and IC50=65.23±2.49 μg/mL, respectively. However, the ethyl acetate fraction possessed the strongest inhibitory effect towards α-Glucosidase (IC50=1.112±0.026 mg/mL). Furthermore, the result showed high levels of phenolic content. The results showed that this plant could be a significant source of medically important natural compounds