Analysis of Multicarrier PWM techniques for Photovoltaic fed Cascaded H-Bridge Multilevel Inverter

Recently multilevel inverter technology emerging as an important alternative in the field of high power, medium voltage energy control. The various topologies for multilevel inverters such as diode-clamped, flying capacitor and cascaded H-bridge have been proposed over the years. This paper analysis the performance of a single phase seven level cascaded H-bridge inverter for photovoltaic applications. The Phase Disposition PWM (PDPWM) technique is used to generate gate signals. The performance is compared for both sinusoidal reference waveform and trapezoidal reference waveform. The analysis is carried out for different modulation index and different shading pattern of photovoltaic (PV) array. The simulation is carried out using MATLAB/SIMULINK software

Optimization, preparation and characterization of rutin-quercetin dual drug loaded keratin nanoparticles for biological applications

Objective(s): Response surface methodology (RSM) by central composite design (CCD) was applied to statistically optimize the preparation of Rutin-Quercetin (Ru-Qr) dual drug loaded human hair keratin nanoparticles as well as evaluate the characteristics. Materials and Methods: The effects of three independent parameters, namely, temperature (X1:10-40 C), surfactant (X2: SDS (1), SLS (2), Tween-20 (3)), and organic solvents (X3: acetone (1),  methanol (2), chloroform (3)) were investigated to optimize the preparation of dual drug loaded keratin nanoparticles, and to understand the effects of dependent parameters namely, drug releasing capacity, average particle size, total antioxidant power, zeta potential, and polydispersity index of Ru-Qr nanoparticles. Optimization was executed by CCD and RSM using statistical software (Design Expert, version 8.0.7.1, Stat-Ease, Inc., Minneapolis, MN, USA). The optimal Ru-Qr dual drug loaded keratin nanoparticles were obtained at temperature (X1): 40ÚC, SDS (X2), and acetone (X3). Results:  Under this conditions to achieve highest drug releasing capacity of 98.3%, average size of nanoparticles are 125 nm, total antioxidant power 98.68%, zeta potential 28.09 mV, and polydispersity index of 0.54. Although majority of the experimental values were relatively well matched with the predicted values. Conclusion: This optimization study could be useful in pharmaceutical industry, especially for the preparation of new nano-therapeutic formulations encapsulated with drug molecules. This nanotechnology based drug delivery system is to overcome multi drug resistance and site specific action without affecting other organs and tissues. The methodology adopted in this work shall be useful in improvement of quality of human health