Enhancement of AC System Stability using Artificial Neural Network Based HVDC Controls

In this paper, investigation is carried out for the improvement of power system stability by utilizing auxiliary controls for controlling HVDC power flow. The current controller model and the line dynamics are considered in the stability analysis. Transient stability analysis is done on a multi-machine system, where, a neural network controller is developed to improve the stability of the power system and to improve the response time of the controller to the changing conditions in power system. The results show the application of the neural network controller in AC-DC power systems and case studied at different fault locations.DOI:http://dx.doi.org/10.11591/ijece.v3i4.259

The use of gas proportional counters to distinguish protons from pions in the cosmic radiation at energies of near or greater than 100 GeV

Several possible methods to distinguish protons and pions in the cosmic radiation at energies of over 100 GeV are discussed. One of these methods based on multiple sampling of ionization losses in an array of gas proportional counters together with a measurement of energy in an ionization calorimeter or momentum in a magnet spectrograph is discussed in greater detail.Fluctuations in ionization losses ("Landau" fluctuations) make the method difficult but not impossible. Experimental results on Landau fluctuations with a variety of incident particles and energies are presented and it is shown that they are in better agreement with the theory of Blunck and Leisegang than with that of Landau.Artificial events in which the sampled ionization losses obeyed the Landau and Blunck and Leisegang distributions are generated on a computer by a Monte Carlo program. Based on an analysis of a sample of 20000 such events by likelihood ratio method the attainable proton-pion separation in the cosmic radiation at 100 GeV energy is presented.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/33382/1/0000780.pd

<i>Wendlandia tinctoria</i> (Roxb.) DC. (Rubiaceae), a key nectar source for butterflies during the summer season in the southern Eastern Ghats, Andhra Pradesh, India

Wendlandia tinctoria is a semi-evergreen tree species. It shows massive flowering for about a month during March-April. The floral characteristics such as the white colour of the flower, lack of odour, short-tubed corolla with deep seated nectar having 15-18% sugar concentration are well tailored for visitation by butterflies. The nectar is hexose-rich and contains the essential amino acids such as arginine and histidine and the non-essential amino acids such as alanine, aspartic acid, cysteine, glysine, hydroxyproline, tyrosine, glutamic acid and serine. The inflorescences with clusters of flowers provide an excellent platform for foraging by butterflies. The flowers are long-lived and attractive to butterflies. A variety of butterflies visit the flowers for nectar and in doing so, they pollinate them. Nymphalids are very diverse and utilize the flowers until exhausted. The flowers being small in size with a small amount of nectar compel the butterflies to do a more laborious search for nectar from a greater number of flowers. But, the clustered state of the flowers is energetically profitable for butterflies to reduce search time and also flight time to collect a good amount of nectar; such a probing behaviour is advantageous for the plant to achieve self- and cross-pollination. Therefore, the study shows that the association between W. tinctoria and butterflies is mutual and such an association is referred to as psychophilous. This plant serves as a key nectar source for butterflies at the study site where floral nectar sources are scarce during the summer season

Entomophily, ornithophily and anemochory in the self-incompatible <i>Boswellia ovalifoliolata</i> Bal. & Henry (Burseraceae), an endemic and endangered medicinally important tree species

Boswellia ovalifoliolata (Burseraceae) is a narrow endemic and endangered deciduous tree species. Its flowering, fruiting and seed dispersal events occur in a leafless state during the dry season. The flowers are small, bisexual, mildly odoriferous and actinomorphic; weakly protandrous but strictly self-incompatible. While insects and sunbirds pollinate the flowers, floral characteristics suggest that entomophily is the principal mode. Both bud and flower feeding by a weevil and flower and fruit feeding by the Palm Squirrel have been found to affect the success of sexual reproduction. The Garden Lizard serves as a predator of pollinating insects, especially bees and wasps, thus influencing pollination of this tree species. Fruit set in open pollination is below 10%, rising to 34% in manual cross-pollination. Limitation of cross-pollination, space constraints for seed production from all flower ovules and availability of limited resources in rocky, dry litter of the forest floor appear to constrain higher fruit set. Mature fruits dehisce and disseminate their lightweight, papery winged seeds with the aid of wind. The study site being windy provides the necessary driving force for effective dispersal of seeds away from parent trees. Seed germination occurs following rainfall but further growth depends on soil water and nutritional status. The success rate of seedling recruitment is highly limited, and it could be due to nutrient-poor soil and water stress resulting from dry spells during the rainy season

Design and experimental analysis of solar-powered water desalination system using humidification?dehumidification

Desalination with solar-powered air heating and packed bed humidification is designed and fabricated using locally available materials. The system with fined type dehumidifier is designed using the LMTD method. There are different solar desalination techniques such as solar still, solar air humidification dehumidification and solar water flash evaporation. Among these desalination techniques, solar air humidification dehumidification was already successfully used in very large-scale desalination but, not effectively tried for small-scale desalination. Desalination system with HDH was designed and fabricated during this research project for small-scale output. There are three main components of the system: Solar air heater, humidifier and dehumidifier. The packed bed was used in the design of humidifier for increasing the surface contact area of air with water. Psychrometric properties are recorded with the use of sensors DHT11 and ESP8266 micro-controller Wi-Fi board. The water temperatures are recorded with PT100 sensors and 8 channels data logger.Scopu

Some Critical Notes on Leonotis nepetifolia (L.) R. Br. var. africana (P. Beauv.) J.K. Morton (Lamiaceae)

The much disregarded Leonotis nepetifolia (L.) R. Br. var. africana (P. Beauv.) J.K. Morton (Lamiaceae), hitherto known only from Africa, is described and illustrated from Greater Hyderabad, Andhra Pradesh, India. The present report extends its distribution to Asia. Some critical notes on diagnostic features are added for greater clarity to discern var. africana from the var. proper

Bilateral Primary Fallopian Tube Adenocarcinoma – A Rare Case

Although fallopian tubes are a common site of metastases, primary fallopian tube carcinoma is considered a rare disease and is often mistaken histologically and clinically for ovarian cancer. The etiology is poorly understood and presenting symptoms are variable and non-specific, with preoperative diagnosis rarely entertained. We put forth our experience of a case of bilateral primary fallopian tube carcinoma which was histopathologically diagnosed after being misinterpreted on ultrasonography