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The main objective of this research work is to analysis the voltage stability of the power system network and its improvement in the network voltage stability of a power system. A system enters a state of voltage instability when a disturbance, increase in load demand, or change in system condition causes a progressive and an uncontrollable drop in voltage or voltage collapse. The continuing increase in demand for electric power has resulted in an increasingly complex, interconnected system, forced to operate closer to the limits of the stability. This has necessitated the implementation of techniques for analyzing and detecting voltage collapse in bus bar or lines prior to its occurrence. Simple Newton Raphson algorithm based voltage stability analysis has been carried out. Matlab based simulations for all the factors that causes voltage instability has been implemented and analyzed for an IEEE 30 bus system. The proposed model is able to identify the behavior of the power systems, network under various voltage stability conditions and its possibility of recovery/stability improvement of the power system network has been discussed. [ABSTRACT FROM AUTHOR]

Acorus calamus, a medicinal herb occasionally planted in the home gardens and often found as garden escape in Kuttanad wetlands of Kerala, India and its rhizome was investigated for its nutritional and antinutritional properties. Proximate composition, mineral profiles, vitamins, total free amino acids, in vitro protein digestibility, calorific value and certain anti nutritional factors like phenol, tannin, phytic acid, trypsin inhibitory and haemaglutinin assay were analysed. The results of proximate analysis revealed the presence of high moisture (68.02 %) and ash (17.3 %) and protein (15.62 %) contents. The carbohydrate (37.26 %), crude lipid (0.00057 %), crude fiber (6.6 %) contents and vitamins (ascorbic acid, beta carotene and tocopherol) were found in appreciable quantity. The total energy value was estimated at 121.65 Kcal/100 g and total free amino acid content was 25.71 µg/500mg. Mineral analyses recorded highest value for Potassium (K) and the lowest value for Phosphorus (P). The other elements like Sodium (Na), Calcium (Ca), Magnesium (Mg), Zinc (Zn) and Copper (Cu) were also found in sufficient amount. The rhizome was also found to contain anti-nutritional factors such as tannins (0.32 µg/g), phytic acid (935.43 mg/100g), phenols (113.68 µg/g) and trypsin inhibitor unit (3.02 mg/g). The results of the present investigation revealed the presence of essential nutrients and also certain antinutritional factors in the rhizome of A. calamus. [ABSTRACT FROM AUTHOR]

This study aimed to determine the activity of ethanolic leaf extract of Vitex negundo L. against HIV-1 Reverse Transcriptase (RT) and to identify and quantify the flavonoids present. The effects of ethanolic (85%) leaf extract of Vitex negundo L. on RT activity in vitro were evaluated with recombinant HIV-1 enzyme, using a non-radioactive HIV-RT colorimetric ELISA kit. In addition, identification and quantification of flavonoids such as Rutin, Luteolin, Myricetin, Quercetin, Kaempherol, Isorhamnetin and Quercetagetin were analysed using HPLC. The plant Vitex negundo L. ethanolic leaf extract exhibited the most notable activity of 92.8% against HIV-1 RT at 200 μg/ml concentration. Phytochemical analysis revealed the presence of steroids, triterpenes, alkaloids, flavanoids, antroquinone glycosides and amino acids. Among 7 flavonoids tested, 6 were identified in the decreasing order of quantity as Kaempherol, Myricetin, Quercetin, Quercetagetin, Isorhamnetin and Luteolin. The study revealed that the plant Vitex negundo L. leaf possess anti-RT substances and probably the flavonoids act as anti-virus agents. [ABSTRACT FROM AUTHOR]