Studies on Optical, Mechanical and Electrical Properties of Organic Nonlinear Optical p-Toluidine p-Toluenesulfonate Single Crystal

The optically transparent and bulk single crystal of p-Toluidine p-Toluenesulfonate (PTPT) was grown by slow evaporation technique. The lattice parameters and crystallinity of the grown crystal were estimated by single crystal XRD. The optical absorption of the crystal was recorded using the UV-Vis-NIR spectrophotometer. The optical bandgap and optical constants of the material were determined by using absorption spectrum. The refractive index of the grown crystal has been determined using the Brewster angle method. The dielectric constant and dielectric loss were measured as a function of frequency and temperature for the grown crystal. Nonlinear optical properties were performed to confirm the SHG efficiency of the grown crystal. Hence, PTPT is an excellent NLO material with enhanced SHG efficiency required for important applications in the field of optoelectronic and photonics. This material exhibits NLO behaviour remarkably due to its better optical and dielectric properties.

Screening of Antiviral Efficacy of Few Seaweeds of Tamil Nadu Coast

Lately there has been a lot of interest worldwide in studies on the antiviral activities of marine natural secondary metabolites,notably marine polysaccharides.It has been established that polysaccharides made from marine sources and their derivatives have antiviral effects against potent viruses.Agricultural,biological,food,and pharmaceutical industries all make extensive use of goods obtained from algae.The most well-known chemical components found in algae are polysaccharides,which have been the subject of a variety of studies because of their varied bioactivities.Polysaccharides made from algae have recently risen to the top of pharmaceutical research due to their fascinating antiviral potential.Currently,COVID-19 can be prevented with vaccination,but the brown alga Sargassum wightii has several bioactive compounds that have the following qualities and may be a better option.S.wightii is one of the marine algae species that is rich in sulfated polysaccharides,the secondary metabolites which have antiviral action and the capacity to prevent viral proliferation.Fucoidan,a long-chain sulfated polysaccharide found in various brown algae,has potent antiviral effects.Additionally,sulfated polysaccharides from green algae(such as ulvans)and red algae(such as carrageenan),and lectins from red algae(such as griffithsin)have antiviral therapeutic agents against coronaviruses and other viruses.This research focuses on screening seaweeds for possible antiviral compounds to treat viral infections notably COVID-19.

An Improved Hybrid Space Vector PWM Technique for IM Drives

In this paper, an improved hybrid space vector pulse width modulation (HSVPWM) technique is proposed for IM (induction motor) drives. The basic principle involved in the proposed random pulse width modulation (RPWM) cuddled SVPWM is amalgamating the pre-calculated switching timings for various sections of hexagonal space vector boundary and the random selection of carrier between two triangular signals, in order to disband acoustic switching noise spectrum with improved fundamental component. The arbitrary selection between triangular carriers, which is decided by digital signal states (Low or High) of the linear feedback shift register (LFSR) based pseudo random binary sequence (PRBS) generator. The SVPWM offers a control degree of freedom in terms of positioning of vectors inside every sampling interval and hence it has six possible variants of the voltage vectors arrangements in each sector. The developed HSVPWM is thoroughly analyzed in using the MATLAB? based simulation for all SVPWM variants. From the simulation and experimental results viz. harmonic spectrum, harmonic spread factor (HSF), total harmonic distortion (THD) etc., and the superiority of the proposed scheme such as better utilization of DC bus and the randomization of the harmonic power are evidenced. For the practical implementation, Xilinx XC3S500E FPGA device has been used.

A Novel Flower Pollination Algorithm to Solve Load Frequency Control for a Hydro-Thermal Deregulated Power System

Load frequency control plays a vital role in power system operation and control. LFC regulates the frequency of larger interconnected power systems and keeps the net interchange of power between the pool members at predetermined values for the corresponding changes in load demand. In this paper, the two-area, hydrothermal deregulated power system is considered with Redox Flow Batteries (RFB) in both the areas. RFB is an energy storage device, which converts electrical energy into chemical energy, that is used to meet the sudden requirement of real power load and hence very effective in reducing the peak shoots. With conventional proportional-integral (PI) controller, it is difficult to get the optimum solution. Hence, intelligent techniques are used to tune the PI controller of the LFC to improve the dynamic response. In the family of intelligent techniques, a recent nature inspired algorithm called the Flower Pollination Algorithm (FPA) gives the global minima solution. The optimal value of the controller is determined by minimizing the ISE. The results show that the proposed FPA tuned PI controller improves the dynamic response of the deregulated system faster than the PI controller for different cases. The simulation is implemented in MATLAB environment.