Improved Step Response of Power System Stabilizer using Fuzzy Logic Controller

As every power system is constantly being subjected to disturbances, we should see that these disturbances do not make the system unstable. Therefor additional signals derived from speed deviation, excitation deviation and accelerating power are injected into voltage regulators. The device to provide these signals is referred as power system stabilizer. The use of power system stabilizers has become very common in operation of large electric power systems. The conventional PSS which uses lead-lag compensation, where gain settings designed for specific operating conditions, is giving poor performance under different loading conditions. Therefore, it is very difficult to design a stabilizer that could present good performance in all operating points of electric power systems. In an attempt to cover a wide range of operating conditions, Fuzzy logic control has been suggested as a possible solution to overcome this problem. In this paper, a systematic approach to fuzzy logic control design is proposed. The study of fuzzy logic power system stabilizer for stability enhancement of a single machine infinite bus system is presented. In order to accomplish the stability enhancement, speed deviation and acceleration of the rotor synchronous generator are taken as the inputs to the fuzzy logic controller. These variables take significant effects on damping the generator shaft mechanical oscillations. The stabilizing signals were computed using the fuzzy membership function depending on these variables. The performance of the system with fuzzy logic based power system stabilizer is compared with the system having conventional power system stabilizer and system without power system stabilize

Chemical characteristics of aerosols in MABL of bay of Bengal and Arabian sea during spring inter-monsoon: a comparative study

The chemical composition of aerosols in the Marine Atmospheric Boundary Layer (MABL) of Bay of Bengal (BoB) and Arabian Sea (AS) has been studied during the spring and inter-monsoon (March-May 2006) based on the analysis of water soluble constituents (Na+, NH4+, K+, Mg2+, Ca2+, Cl-, NO3- and SO42-), crustal elements (Al, Fe, and Ca) and carbonaceous species (EC, OC). The total suspended particulates (TSP) ranged from 5.2 to 46.6 μg m-3 and 8.2 to 46.9 μg m-3 during the sampling transects in the BoB and AS respectively. The water-soluble species, on average, accounted for 44% and 33% of TSP over BoB and AS respectively, with dominant contribution of SO42- over both the oceanic regions. However, distinct differences with respect to elevated abundances of NH4+ in the MABL of BoB and that of Na+ and Ca2+ in AS are clearly evident. The non-sea-salt component of SO42- ranging from 82 to 98% over BoB and 35 to 98% over AS; together with nss-Ca2+/nss-SO42- equivalent ratios 0.12 to 0.5 and 0.2 to 1.16, respectively, provide evidence for the predominance of anthropogenic constituents and chemical transformation processes occurring within MABL. The concentrations of OC and EC average around 1.9 and 0.4 μg m-3 in BoB and exhibit a decreasing trend from north to south; however, abundance of these carbonaceous species are not significantly pronounced over AS. The abundance of Al, used as a proxy for mineral aerosols, varied from 0.2 to 1.9 μg m-3 over BoB and AS, with a distinctly different spatial pattern - decreasing north to south in BoB in contrast to an increasing pattern in the Arabian Sea

A New Control Strategy For Cascaded H-Bridge Multilevel PV Inverter With Distributed MPPT For Grid Connected Applications

A three - phase  modular  cascaded H-bridge multilevel inverter for a grid-connected photovoltaic (PV) system is presented in this project. To maximize the solar energy extraction of each PV string, an individual maximum power point tracking (MPPT) control scheme is applied, which allows the independent control of each dc-link voltage. PV mismatches may introduce unbalanced power supplied to the three-phase system. To solve this issue, a control scheme with modulation compensation is proposed. The three-phase modular cascaded multilevel inverter prototype has been built. A fuzzy controller is implemented in this project in the place of PI controller to balance the three phase grid current . Each H-bridge module is connected to a 185-W solar panel. Simulation results are presented to verify the feasibility of the proposed approach in MATLAB /SIMULINK environment.

Jamming modulates coalescence dynamics of shear-thickening colloidal droplets

Recent investigations into coalescence dynamics of complex fluid droplets revealed the existence of sub-Newtonian behaviour for polymeric fluids (elastic and shear thinning). We hypothesize that such delayed coalescence or sub-Newtonian coalescence dynamics may be extended to the general class of shear thickening fluids. To investigate this droplets of aqueous corn-starch suspensions were chosen and its coalescence in sessile pendant configuration was probed by high-speed real time imaging. Temporal evolution of the neck (growth) during coalescence was quantified as a function of suspended particle weight fraction \phi_w. The necking behaviour was found to evolve as the power-law relation $R=at^b$ where R is neck radius with exponent \b\le0.5 implying it is a subset of the generic sub-Newtonian coalescence. Second significant delay in the coalescence dynamics is observed for particle fractions beyond the jamming fraction {\ \phi}_w>\ \phi_J\geq0.35}. Our proposed theoretical model captures this delay implicitly through altered suspension viscosity stemming from increased particle content

SIMULTANEOUS ESTIMATION OF MECLIZINE HYDROCHLORIDE AND NICOTINIC ACID IN PHARMACEUTICAL DOSAGE FORM BY RP-HPLC METHOD

A simple, selective, rapid, precise and economical reverse phase high performance liquid chromatographicmethod has been developed for the simultaneous estimation of meclizine hydrochloride and nicotinic Acid frompharmaceutical formulation using C18 (25 cm x 4.6 mm i.d.,

Implementation of Area Efficient Multiple Passband FIR Filter for 5G Applications

971-978In television, mobile and digital signal processing applications, efficient multiband filters have great usage. The proposed architecture gives the Reconfigurable Finite Impulse Response (FIR) filter with multiple pass bands. Implementation of architecture utilizes FIR filter with control logic and frequency selection circuit. By adjusting the parameters of the filter, proper bandwidth of the pass band can be achieved and the ripple content in the pass band and stop band can be controlled. The efficient way to adjust the bandwidth is to choose the effective value of the filter length and coefficients. The area efficient multiple passband FIR filter using control logic has been proposed with order (n = 4 and 11). Target device that has been selected for implementation is Field Programmable Gate Array (FPGA) Virtex 4 Device. The Look-Up Tables (LUT) utilization for the implemented architecture with length of filter (n = 11) is observed to be 6%

Implementation of Area Efficient Multiple Passband FIR Filter for 5G Applications

In television, mobile and digital signal processing applications, efficient multiband filters have great usage. The proposed architecture gives the Reconfigurable Finite Impulse Response (FIR) filter with multiple pass bands. Implementation of architecture utilizes FIR filter with control logic and frequency selection circuit. By adjusting the parameters of the filter, proper bandwidth of the pass band can be achieved and the ripple content in the pass band and stop band can be controlled. The efficient way to adjust the bandwidth is to choose the effective value of the filter length and coefficients. The area efficient multiple passband FIR filter using control logic has been proposed with order (n = 4 and 11). Target device that has been selected for implementation is Field Programmable Gate Array (FPGA) Virtex 4 Device. The Look-Up Tables (LUT) utilization for the implemented architecture with length of filter (n = 11) is observed to be 6%

PLSCR1 is a cell-autonomous defence factor against SARS-CoV-2 infection

Understanding protective immunity to COVID-19 facilitates preparedness for future pandemics and combats new SARS-CoV-2 variants emerging in the human population. Neutralizing antibodies have been widely studied; however, on the basis of large-scale exome sequencing of protected versus severely ill patients with COVID-19, local cell-autonomous defence is also crucial1,2,3,4. Here we identify phospholipid scramblase 1 (PLSCR1) as a potent cell-autonomous restriction factor against live SARS-CoV-2 infection in parallel genome-wide CRISPR–Cas9 screens of human lung epithelia and hepatocytes before and after stimulation with interferon-γ (IFNγ). IFNγ-induced PLSCR1 not only restricted SARS-CoV-2 USA-WA1/2020, but was also effective against the Delta B.1.617.2 and Omicron BA.1 lineages. Its robust activity extended to other highly pathogenic coronaviruses, was functionally conserved in bats and mice, and interfered with the uptake of SARS-CoV-2 in both the endocytic and the TMPRSS2-dependent fusion routes. Whole-cell 4Pi single-molecule switching nanoscopy together with bipartite nano-reporter assays found that PLSCR1 directly targeted SARS-CoV-2-containing vesicles to prevent spike-mediated fusion and viral escape. A PLSCR1 C-terminal β-barrel domain—but not lipid scramblase activity—was essential for this fusogenic blockade. Our mechanistic studies, together with reports that COVID-associated PLSCR1 mutations are found in some susceptible people3,4, identify an anti-coronavirus protein that interferes at a late entry step before viral RNA is released into the host-cell cytosol

Novel genetic loci underlying human intracranial volume identified through genome-wide association

Intracranial volume reflects the maximally attained brain size during development, and remains stable with loss of tissue in late life. It is highly heritable, but the underlying genes remain largely undetermined. In a genome-wide association study of 32,438 adults, we discovered five novel loci for intracranial volume and confirmed two known signals. Four of the loci are also associated with adult human stature, but these remained associated with intracranial volume after adjusting for height. We found a high genetic correlation with child head circumference (ρgenetic=0.748), which indicated a similar genetic background and allowed for the identification of four additional loci through meta-analysis (Ncombined = 37,345). Variants for intracranial volume were also related to childhood and adult cognitive function, Parkinson’s disease, and enriched near genes involved in growth pathways including PI3K–AKT signaling. These findings identify biological underpinnings of intracranial volume and provide genetic support for theories on brain reserve and brain overgrowth