Unveiling the nature of giant radio galaxies

The thesis deals with the study of giant radio galaxies (GRGs), which are radio galaxies of megaparsec sizes. Their enormous size and rarity have been investigated in this thesis. The study included searching and consequent finding of the largest samples of GRGs and thereby enabling to study of their properties in detail. Also, the properties were compared to smaller sized radio galaxies to investigate possible differences which could be the factor for their giant sizes.Galaxie

Temperature Compensated Ultrasonic Ranging and Location finder for Blind Person

This paper is intended to provide a theoretical model of object detection and real time assistance via Global Positioning System(GPS).This paper aims at the development of an Electronic Travelling Aid (ETA) kit to help the blind people to find obstacle free path. This ETA is fixed to the stick of the blind people. When the object is detected near to the blinds’ stick it alerts them with the help of vibratory circuit. Ultrasonic sensors are used to evaluate distance of the objects around the blind person to guide the user towards the secure and available path. Output is in the form of vibrations which the blind person can easily recognize. The hardware of entire system contains ARM7 (LPC2138), temperature sensor, ultrasonic sensors and mobile vibrator, Global positioning system (GPS) module and Global System for Mobile (GSM) module. It contains temperature compensation method to reduce the error in measurement of distance using ultrasonic sensors. DOI: 10.17762/ijritcc2321-8169.15068

A low-frequency study of recently identified double-double radio galaxies

In order to understand the possible mechanisms of recurrent jet activity in radio galaxies and quasars, which are still unclear, we have identified such sources with a large range of linear sizes (220 $-$ 917 kpc), and hence time scales of episodic activity. Here we present high-sensitivity 607-MHz Giant Metrewave Radio Telescope (GMRT) images of 21 possible double-double radio galaxies (DDRGs) identified from the FIRST survey to confirm their episodic nature. These GMRT observations show that none of the inner compact components suspected to be hot-spots of the inner doubles are cores having a flat radio spectrum, confirming the episodic nature of these radio sources. We have indentified a new DDRG with a candidate quasar, and have estimated the upper spectral age limits for eight sources which showed marginal evidence of steepening at higher frequencies. The estimated age limits (11 $-$ 52 Myr) are smaller than those of the large-sized ($\sim$ 1 Mpc) DDRGs.Comment: Accepted for publication in MNRAS. 14 pages, 7 figure

A Review and an Approach of Water Pollution Indication using Arduino Uno

Drinking water is critical for the wellbeing and prosperity of all people and creatures because water play major role in all living beings and most danger disease are caused by water and it is our duty to provide clean and safe water and also to monitor the pollution level in water it is additionally essential for farming utilization for good product yielding and natural way of life linkage wellbeing issues. With over 200 children dying per day due to unsafe water, drinking water crisis is ranked one on the global risk by World Economic Forum, 2015. This paper presents an easy and comprehensive methodology is microcontroller sensor based system continuous observing and pollution recognition for both drinking and non-drinking water dissemination frameworks and in addition for customer locales

A Review and an Approach of Flying Electric Generators as Alternate Source of Energy

This paper presents a review of flying electric generators which are used to harness kinetic energy in powerful, persistent high altitude winds. It has been found that FEGs could give individual output of up to 40MW. It is a lighter wind turbine that rotates about a horizontal axis in response to wind, generating electrical energy. This electrical energy is transferred down for immediate use, or to a set of batteries for later use, or to the power grid. This paper presents the critical analysis of existing literature which is relevant to flying electric generator Though, the literature consists of a lot many research contributions, but, here, we have analyzed some important research and review papers. The existing approaches are categorized based on the basic concepts involved in the mechanisms. The emphasis is on the concepts used by the concerned authors, the database used for experimentations and the performance evaluation parameters. Their claims are also highlighted. Finally, the findings are summarized related to the studied and analyzed research papers. Paper concludes with the motivation behind identified problem

Study of effects of donepezil and aspirin on working memory in rats using electroconvulsive shock model

Background: Memory is the most common cognitive ability lost with dementia commonly seen in Alzheimer’s disease (AD). Donepezil was the first cholinesterase inhibitor to be licensed in UK for AD. There is preliminary evidence that aspirin decreases the risk and delays the onset of AD. Low dose aspirin users had numerically lower prevalence of Alzheimer’s dementia and had better cognitive function than non-users.Methods: Retention of conditioned avoidance response (CAR) was assessed by using repeated electroconvulsive shocks (ECS) in rats. Rats were divided into five groups: control (pretreated with distilled water), ECS (150 V, 50 Hz, with intensity of 210 mA for 0.5 sec) pretreated, combined aspirin (6.75 mg/kg) and pretreated ECS, combined donepezil (0.32 mg/kg) and pretreated ECS, combined aspirin, donepezil and pretreated ECS groups. Data were analyzed using the Chi-square test and ANOVA.Results: Findings show that administration of ECS daily for 8 days results in transient amnesia and disruption of retention of CAR. Aspirin and donepezil administration significantly increased the retention of CAR in comparison to ECS. However, aspirin failed to show an increase in the retention of CAR as compared to donepezil. The combination of the two drugs showed statistically significant increase in the retention of CAR than either of these drugs given alone.Conclusion: Neuroinflammation plays an important role in the pathophysiology of neurodegenerative disorder like AD. Combination of aspirin with donepezil increased the nootropic and neuroprotective effect of aspirin and thus may hold great clinical significance in such disorders

Automatic Overhead Water Tank Cleaning System: A Review and an Approach

Aim of this paper is to develop a mechanical system for cleaning domestic cylindrical water tank. The mechanical system includes two main mechanisms which are rack and pinion gear mechanism and reciprocating four bar linkage mechanism. The rack and pinion arrangement is used to move whole mechanical system up and down for cleaning the cylindrical tank. The rack is fixed on the motor and the four-bar mechanism is attached to the motor shaft. PVC brushes are attached to the ends of the four-bar linkage. Four bar linkage is made in such a way that it can be adjusted according to inside diameter of the tank. When the motor is started the linkage rotates and with the help of brushes, cleaning of wall and base of tank takes place. The purpose of this project is to reduce the human efforts and to avoid the chemical influence on health of person entering the tank for cleaning. In this modern world, cleaning of overhead tanks manually is a tedious job. To overcome this we have aimed at tackling the disadvantages of cleaning overhead tanks, so an automatic system overhead tank cleaning is designed to provide high safety, high efficiency, less time for cleaning and to avoid environmental pollution problems. Purpose of this paper is to clean domestic cylindrical water tank with the help of mechatronics system. The mechatronics system consists of a grooved gear rod attached to two arms with brushes at ends. The two arms are connected to the gear rod by nut. By rotating the gear rod, the up and down motion of the two arms is achieved. The gear rod is rotated with the help of a D.C gear motor. The main grooved shaft is powered by an A.C motor. The motor and the shaft are connected by a rubber belt. The clockwise rotation of the main shaft will make the arms move and vice versa. The whole operation is controlled by a circuit consisting of relay switches, buttons, and PIC microcontroller. The number of times for the operation to repeat can be fed into the circuit. The achievement of this project is reduction of cost and manual labour because there will be harmful diseases for the person who will go inside and it will affect the health as well as the other human being who consumes water from the tank

The LOFAR view of intergalactic magnetic fields with giant radio galaxies

Context. Giant radio galaxies (GRGs) are physically large radio sources that extend well beyond their host galaxy environment. Their polarization properties are affected by the poorly constrained magnetic field that permeates the intergalactic medium on megaparsec scales. A low frequency (< 200 MHz) polarization study of this class of radio sources is now possible with LOFAR. Aims. Here we investigate the polarization properties and Faraday rotation measure (RM) of a catalog of GRGs detected in the LOFAR Two-meter Sky Survey. This is the first low frequency polarization study of a large sample of radio galaxies that were selected on their physical size. We explore the magneto-ionic properties of their under-dense environment and probe intergalactic magnetic fields using the Faraday rotation properties of their radio lobes. LOFAR is a key instrument for this kind of analysis because it can probe small amounts of Faraday dispersion (< 1 rad m-2), which are associated with weak magnetic fields and low thermal gas densities. Methods. We used RM synthesis in the 120-168 MHz band to search for polarized emission and to derive the RM and fractional polarization of each detected source component. We study the depolarization between 1.4 GHz and 144 MHz using images from the NRAO VLA Sky Survey. We investigate the correlation of the detection rate, the RM difference between the lobes, and the depolarization with different parameters as follows: the angular and linear size of the sources and the projected distance from the closest foreground galaxy cluster. In our sample, we also included 3C 236, which is one of the largest radio galaxies known. Results. From a sample of 240 GRGs, we detected 37 sources in polarization, all of which have a total flux density above 56 mJy. We detected significant RM differences between the lobes, which would be inaccessible at gigahertz frequencies, with a median value of ∼1 rad m-2. The fractional polarization of the detected GRGs at 1.4 GHz and 144 MHz is consistent with a small amount of Faraday depolarization (a Faraday dispersion < 0.3 rad m-2). Our analysis shows that the lobes are expanding into a low-density (< 10-5 cm-3) local environment that is permeated by weak magnetic fields (< 0.1  μG) with fluctuations on scales of 3-25 kpc. The presence of foreground galaxy clusters appears to influence the polarization detection rate up to 2R500. In general, this work demonstrates the ability of LOFAR to quantify the rarefied environments in which these GRGs exist and highlights them as an excellent statistical sample to use as high precision probes of magnetic fields in the intergalactic medium and the Milky Way

Discovery of giant radio galaxies from NVSS: radio and infrared properties

Giant radio galaxies (GRGs) are one of the largest astrophysical sources in the Universe with an overall projected linear size of ∼0.7 Mpc or more. The last six decades of radio astronomy research has led to the detection of thousands of radio galaxies. However, only ∼300 of them can be classified as GRGs. The reasons behind their large size and rarity are unknown. We carried out a systematic search for these radio giants and found a large sample of GRGs. In this paper, we report the discovery of 25 GRGs from the National Radio Astronomy Observatory Very Large Array Sky Survey, in the red-shift range z ∼ 0.07 to 0.67. Their physical sizes range from ∼0.8 Mpc to ∼4 Mpc. Eight of these GRGs have sizes ≥2 Mpc, which is a rarity. Here, for the first time, we investigate the mid-infrared (IR) properties of the optical hosts of the GRGs and classify them securely into various active galactic nuclei types using the WISE mid-IR colours. Using radio and IR data, four of the hosts of the GRGs were observed to be radio-loud quasars that extend up to 2 Mpc in radio size. These GRGs missed detection in earlier searches possibly because of their highly diffuse nature, low surface brightness and lack of optical data. The new GRGs are a significant addition to the existing sample. They will contribute to a better understanding of the physical properties of radio giants.Large scale structure and cosmolog

uGMRT detection of cluster radio emission in low-mass Planck Sunyaev-Zel'dovich clusters

Galaxie