Evaluation and Quantification of Anionic Surfactant in the Gomti River at Lucknow City, India

In this paper, an attempt has been made to check the level of surfactants particularly in drinking water, which can lead to toxicity in human body system. In this study, a total of 10 locations were selected to enumerate the concentration of surfactants and other physicochemical parameters with metals in the flowing water of river during pre-monsoon 2019. Analyzed result showed that the concentration of surfactants was significantly high and other parameters were also high. It was also found that river at the vicinity of town areas or midstream in the Lucknow city contained high amount of an anionic surfactants due to the nonpoint sources generated by human activities, low concentration was found in upstream, and average concentration was found in downstream, showing natural degradation of surfactants. The values of other parameters were higher than the prescribed limit, which is the serious problem for human being

Globular Cluster UVIT Legacy Survey (GlobULeS) – II. Evolutionary status of hot stars in M3 and M13

We present the first comprehensive study of the most massive globular cluster, Omega Centauri, in the far-ultraviolet (FUV), extending from the center to ∼28% of the tidal radius using the Ultraviolet Imaging Telescope on board AstroSat. A comparison of the FUV-optical color–magnitude diagrams with available canonical models reveals that horizontal branch (HB) stars bluer than the knee (hHBs) and the white dwarfs (WDs) are fainter in the FUV by ∼0.5 mag than model predictions. They are also fainter than their counterparts in M13, another massive cluster. We simulated HB with at least five subpopulations, including three He-rich populations with a substantial He enrichment of Y up to 0.43 dex, to reproduce the observed FUV distribution. We find the He-rich younger subpopulations to be radially more segregated than the He-normal older ones, suggesting an in situ enrichment from older generations. The ω Cen hHBs span the same Teff range as their M13 counterparts, but some have smaller radii and lower luminosities. This may suggest that a fraction of ω Cen hHBs are less massive than those of M13, similar to the result derived from earlier spectroscopic studies of outer extreme HB stars. The WDs in ω Cen and M13 have similar luminosity–radius–Teff parameters, and 0.44–0.46 M⊙ He-core WD model tracks evolving from progenitors with Y = 0.4 dex are found to fit the majority of these. This study provides constraints on the formation models of ω Cen based on the estimated range in age, [Fe/H], and Y (in particular) for the HB stars

Light Curve and Spectral Evolution of Type IIb Supernovae

Stripped-Envelope Supernovae constitute the sub-class of core-collapse supernovae that strip off their outer hydrogen envelope due to high stellar winds or due to interaction with a binary companion where mass transfer occurs as a result of Roche lobe overflow. We present here the photometric and spectroscopic analysis of a member of this class : SN 2015as classified as a type IIb supernova. Light curve features are similar to those of SN 2011fu while spectroscopic features are quite similar to those of SN 2008ax and SN 2011dh. Early epoch spectra have been modelled with SYN++ which indicates a photospheric velocity of 8500 km sec-1 and temperature of 6500K. Spectroscopic lines show transitioning from H to He features confirming it to be a type IIb supernova. Prominent oxygen and calcium emission features are indicative of the asymmetry of the ejecta. We also estimate the signal to noise ratio of the 3.6m telescope data. This telescope is located at ARIES, Devasthal, Nainital at an altitude of 2450m. We also show the comparison plots of spectra taken with a 2m and 4m class telescopes to enlighten the importance of spectral features displayed by bigger diameter telescopes

Voltage Profile Improvement of Transmission Lines Using Static VAR Compensator

ABSTRACT: In the present scenario the power system are operated nearer to their stability limits due to economic and environmental reasons. Now days a stable and secure operation of a power system is therefore a very important and challenging issue. Efficient transmission of voltage and stable operation of the power system is very much essential. The stability has been given much attention by power system researchers and planners in recent years, and is being regarded as one of the major sources of power system problems and insecurity. To compensate these problems in transmission system svc is used. A static VAR compensator is chosen as a low cost solution to replace a conventional capacitor bank, thus allowing a continuous and flexible nodal voltage adjustment. Due to simplest structure, easy designing and low cost, PI controller is used in SVC as voltage regulator is used to regulate the voltage in most industries. In this paper shunt FACTS device-SVC is used in transmission line for improving the voltage profile and stability. MATLAB Simulink platform has been used in this study. KEYWORDS: shunt device, transmission line, MATLAB, SVC, voltage stability. I.INTRODUCTION Static VAR Compensators can be very effective in controlling voltage fluctuations at rapidly varying loads. Unfortunately, the price for such flexibility is high. Nevertheless, they are often the only cost-effective solution for many loads located in remote areas where the power system is weak As the disturbance are arises in the system due any abnormal condition of fault, it goes to transient oscillations. These unwanted oscillations can change the performance characterics of applications. Hence this is required to control and is done by the use the same shunt FACTS device Static VAR Compensator (SVC) designed with auxiliary controllers Hence there is a requirement of devices which can control the random fluctuations and the transient oscillations comes in the transmission line voltage during transmission. It is necessary that system has very less overshoot and very less settling time for retain of voltage in steady level. So for this from the last few years static VAR compensator plays an important role in voltage regulation in AC Transmission Systems. A Static VAR Compensators provides such system improvements and benefits by controlling Shunt reactive power sources, both capacitive and inductive, with fast power electronic switching devices. The shunt connected, fixed or mechanically switched reactors are applied to minimize th

Frequency and Temperature Dependence of Dielectric Properties of Pure Poly Vinylidene Fluoride (PVDF) Thin Films

In this work we have evaluated the dielectric properties of Poly Vinylidene fluoride (PVDF) thin films of thickness ( approximately 20 mu m) as a function of temperature from 40-70 degree C and frequency varying from 500 Hz to 100 kHz respectively for Al-Al and Cu-Cu electrode configuration. The dielectric constant values increases with the increase in temperature. A broad peak is found at around (70 plus or minus 5) degree C. The maximum value of dielectric constant and dielectric losses were attributed to the phase transition of the polymer. The variation in dielectric constant and loss tangent suggest the net effect of some internal field within the polymer along with the external A.C. field