A Novel Fuzzy Logic Based Technique to Find the Criticality of Power Transformer

Determining the current prevailing conditions in the transformer is still a challenge and an attempt is made for meeting the same challenge. In this paper a novel system based on fuzzy logic is developed which considers thermal, electrical and mechanical conditions prevailing in the transformer and gives the critical status of the transformer at an aggregate. The developed system also facilitates to give the critical condition of Paper thermal, Oil thermal, Partial discharge, Electrical arching, Dissolved gas analysis(DGA), Break down voltage and sweep frequency response analysis(SFRA) individually so that corresponding preventive measures can be taken by the technologists. This system consists of 10 fuzzy logic controllers whose connections are made by considering technical conditions and reasons, the corresponding rule bases of these fuzzy logic controllers were developed by considering various standards and experience of TIFAC CORE in NIT-Hamirpur. This fuzzy logic based system is tested for various transformers and found that it is highly précised in classifying the critical statues of any transformer as well as all identifying the current prevailing conditions

Evaluation of the Anxiolytic Activity of NR-ANX-C (a Polyherbal Formulation) in Ethanol Withdrawal-Induced Anxiety Behavior in Rats

The present study investigates the anxiolytic activity of NR-ANX-C, a standardized polyherbal formulation containing the extracts of Withania somnifera, Ocimum sanctum, Camellia sinensis, Triphala, and Shilajit in ethanol withdrawal- (EW-) induced anxiety behavior in rats. Ethanol dependence in rats was produced by substitution of drinking water with 7.5% v/v alcohol for 10 days. Then, ethanol withdrawal was induced by replacing alcohol with drinking water, 12 hours prior to experimentation. After confirming induction of withdrawal symptoms in the alcohol deprived animals, the anxiolytic activity of the test compound in graded doses (10, 20, and 40 mg/kg) was compared to the standard drug alprazolam (0.08 mg/kg) in the elevated plus maze and bright and dark arena paradigms. In our study, single and repeated dose administration of NR-ANX-C reduced EW-induced anxiety in a dose-dependent manner. Even though the anxiolytic activity was not significant at lower doses, NR-ANX-C at the highest dose tested (40 mg/kg) produced significant anxiolytic activity that was comparable to the standard drug alprazolam. Based on our findings we believe that NR-ANX-C has the potential to be used as an alternative to benzodiazepines in the treatment of EW-induced anxiety

Ameliorative Effect of Ginger on Blood Glucose Levels and Cardiac TCA Cycle Enzymes Activity in STZ Induced Diabetic Rat

This study aimed to investigate the effects of ginger administration on altered blood glucose levels, cytosolic and mitochondrial enzymes (TCA cycle enzymes) activity in streptozotocin-induced diabetes rats. The study divided Wistar strain rats into five groups: normal control, ginger treated, diabetic control, diabetic plus ginger treated, and diabetic plus glibenclamide treated groups. The diabetic group had significantly elevated blood glucose levels, which were significantly lowered by ginger administration. The cytosolic enzyme G6PDH activity was significantly (P<0.001) decreased along with a significant increase in the LDH activity in diabetic rats heart tissue. The activities of SDH, MDH, GDH in the heart tissue of diabetic rats were significantly decreased, but the daily oral treatment of ginger to diabetic rats for thirty days reversed the above changes in a significant (P<0.001) manner. The study demonstrated that an ethanolic extract of ginger could lower blood glucose levels, improve enzyme activities and body weight in diabetic rats. This suggests that ginger extracts could be used as a cardio-protective supplement to reverse diabetic-induced complications

Effect of Magnetic field on Partial Discharge Initiated by Metallic Particle in Thermally Aged Natural Esters under AC and Harmonic Voltages

This paper reports the experimental and theoretical investigations of particle levitation voltage on thermally aged ester fluid, under AC and harmonic AC voltages, in the presence of both electric and magnetic fields (130 mT and 160 mT). The results indicate a higher sensitivity to identify partial discharge (PD) initiated due to particle movement in aged ester fluids with an ultra-high frequency (UHF) sensor than the fluorescent fiber technique. The cause for the reduction in sensitivity of PD detection due to the fluorescent fiber technique with thermally aged fluid is analyzed using steady-state fluorescent measurement. The reduction in the levitation voltage noticed under high-frequency AC voltages is much more severe than its impact under the fundamental frequency of AC supply voltage. In addition, the presence of a magnetic field reduces the magnitude of levitation voltage substantially. The UHF signals generated due to particle movement-initiated discharges with aged ester fluids indicate a shift in its dominant frequency of 0.9 GHz under the absence of a magnetic field to around 0.6 GHz with the effect of a magnetic field

Pre-Breakdown and Breakdown Behavior of Synthetic and Natural Ester Liquids under AC Stress

In the last decades, a large focus is being placed on the sustainability and safety of the power transformer spectrum. Ester liquids, which have interesting properties such as high fire point and biodegradability, are gaining needed attraction. Since in-service condition, thermal aging deteriorates the physicochemical and electrical properties of liquid dielectrics, it is important to study their long-term behavior. In this contribution, the pre-breakdown and breakdown behavior of ester fluids (synthetic and natural) under AC stress are investigated. Important characteristics, such as partial discharge pre-inception voltage, partial discharge inception voltage, breakdown voltage, average streamer velocity, and inception electric field, were assessed. The influence of the radius of curvature (of high voltage needle electrode) as well as the thermal degradation of typical ester liquids are also discussed. Mineral oil was also included in the tests loop as a benchmark for comparative purposes. It is found that the pre-inception voltage of ester liquids was, in most cases, higher than that of mineral oil. For a given radius of curvature, the streamer inception and breakdown voltages decreased with thermal aging. During the streamer initiation, the electric field at the electrode tip decreased with the increase in the radius of curvature. The velocity of the streamers seems to increase with the decrease in the radius of curvature. The period of vulnerability, the so-called “delay time”, seems to be independent of the aging or the radius of curvature for a given condition of the liquid

Green Synthesis of Silver Nanoparticles using Litsea glutinosa L. Leaves and Stem Extracts and their Antibacterial Efficacy

The present study explores the green approach for the preparation of silver nanoparticles (AgNPs) through the reduction of silver nitrate by the cell-free stem and leaf aqueous extracts of Litsea glutinosa (L.glutinosa) and its potential antibacterial activity. The analytical instruments include scanning electron microscopy, Fourier transforms infrared spectroscopy, UV-visible spectroscopy, and X-ray diffraction spectroscopy confirmed the synthesis of smaller, uniformly spherical AgNPs (10-40 nm). The average crystalline size of prepared AgNPs produced by L. glutinosa leaf extract was found to be 19 mm. From UV-visible spectral analysis, the maximum absorbance peak appeared at 444 nm for leaf extract AgNPs different from stem extract AgNPs (422 nm), which are found to be specific for AgNPs. The L.glutinosa stem extract-assisted AgNPs have shown significant antibacterial activity against Bacillus subtilis (Gram-positive) and Escherichia coli (Gram-negative) in comparison to Gentamycin. Hence, the AgNPs obtained by green synthesis can be therapeutically explored against bacterial infections

In-orbit Performance of UVIT on ASTROSAT

We present the in-orbit performance and the first results from the ultra-violet Imaging telescope (UVIT) on ASTROSAT. UVIT consists of two identical 38cm coaligned telescopes, one for the FUV channel (130-180nm) and the other for the NUV (200-300nm) and VIS (320-550nm) channels, with a field of view of 28 $arcmin$. The FUV and the NUV detectors are operated in the high gain photon counting mode whereas the VIS detector is operated in the low gain integration mode. The FUV and NUV channels have filters and gratings, whereas the VIS channel has filters. The ASTROSAT was launched on 28th September 2015. The performance verification of UVIT was carried out after the opening of the UVIT doors on 30th November 2015, till the end of March 2016 within the allotted time of 50 days for calibration. All the on-board systems were found to be working satisfactorily. During the PV phase, the UVIT observed several calibration sources to characterise the instrument and a few objects to demonstrate the capability of the UVIT. The resolution of the UVIT was found to be about 1.4 - 1.7 $arcsec$ in the FUV and NUV. The sensitivity in various filters were calibrated using standard stars (white dwarfs), to estimate the zero-point magnitudes as well as the flux conversion factor. The gratings were also calibrated to estimate their resolution as well as effective area. The sensitivity of the filters were found to be reduced up to 15\% with respect to the ground calibrations. The sensitivity variation is monitored on a monthly basis. UVIT is all set to roll out science results with its imaging capability with good resolution and large field of view, capability to sample the UV spectral region using different filters and capability to perform variability studies in the UV.Comment: 10 pages, To appear in SPIE conference proceedings, SPIE conference paper, 201

Characteristics of Aerosol Spectral Optical Depths over Manora Peak, Nainital −- A High Altitude Station in the Central Himalayas

We present, for the first time, spectral behaviour of aerosol optical depths (AODs) over Manora Peak, Nainital located at an altitude of $\sim$ 2 km in the Shivalik ranges of central Himalayas. The observations were carried out using a Multi-Wavelength solar Radiometer during January to December 2002. The main results of the study are extremely low AODs during winter, a remarkable increase to high values in summer and a distinct change in the spectral dependencies of AODs from a relatively steeper spectra during winter to a shallower one in summer. During transparent days, the AOD values lie usually below 0.08 while during dusty (turbid) days, it lies between 0.08 to 0.69 at 0.5 $\mu$m. The average AOD value at 0.5 $\mu$m during winters, particularly in January and February, is $\sim 0.03\pm0.01$. The mean aerosol extinction law at Manora Peak during 2002 is best represented by $0.10 \lambda^{-0.61}$. However during transparent days, which almost covers 40% of the time, it is represented by $0.02 \lambda^{-0.97}$. This value of wavelength exponent, representing reduced coarse concentration and presence of fine aerosols, indicates that the station measures aerosol in the free troposphere at least during part of the year.Comment: 10 pages, 5 figures, significantly shortened, main conclusions unchanged, accepted for publication in Jr. of Geophys. Reasearch - Atmosphere