Dynamics of Metallic Particle Contamination in Gas Insulated Substation (GIS)

This paper analyses the movement of free conducting particles inside a single phase Gas Insulated Bus duct(GIB).A two dimensional mathematical model was proposed for determining the movement pattern of metallic particle in GIB by considering all the forces acting on the particle like gravitational, drag and the electric field forces. These particles may be free to move in the electric field or may be fixed on the conductors, thus enhancing local surface fields. Electric fields at the instantaneous contaminated particle locations were computed using Charge Simulation Method (CSM).To determine the particle trajectory in a single phase Gas Insulated Bus duct (GIB), an enclosure diameter 152 mm and conductor diameter 55 mm is considered. The simulation of the particle movement was carried under different AC voltage levels like 100KV, 132KV, 145KV and 175KV class enclosure of GIB for aluminum, copper and silver particles. The results of the simulation have been presented and analyzed in this paper

Renewable Energy Systems: Development and Perspectives of a Hybrid Solar-Wind System

Considering the intermittent natural energy resources and the seasonal un-balance, a phtovoltaic-wind hybrid electrical power supply system was developed to accommodate remote locations where a conventional grid connection is inconvenient or expensive. However, the hybrid system can also be applied with grid connection and owners are allowed to sell excessive power back to the electric utility. The proposed set-up consists of a photo-voltaic solar-cell array, a mast mounted wind generator, lead-acid storage batteries, an inverter unit to convert DC to AC, electrical lighting loads, electrical heating loads, several fuse and junction boxes and associated wiring, and test instruments for measuring voltages, currents, power factors, and harmonic contamination data throughout the system. The proposed hybrid solar-wind power generating system can be extensively used to illustrate electrical concepts in hands-on laboratories and also for demonstrations in the Industrial Technology curriculum. This paper describes an analysis of local PV-wind hybrid systems for supplying electricity to a private house, farmhouse or small company with electrical power depending on the site needs. The major system components, work principle and specific working condition are presented

Low-energy sector of the S=1/2 Kagome antiferromagnet

Starting from a modified version of the the S=1/2 Kagome antiferromagnet to emphasize the role of elementary triangles, an effective Hamiltonian involving spin and chirality variables is derived. A mean-field decoupling that retains the quantum nature of these variables is shown to yield a Hamiltonian that can be solved exactly, leading to the following predictions: i) The number of low lying singlet states increase with the number of sites N like 1.15 to the power N; ii) A singlet-triplet gap remains in the thermodynamic limit; iii) Spinons form boundstates with a small binding energy. By comparing these properties with those of the regular Kagome lattice as revealed by numerical experiments, we argue that this description captures the essential low energy physics of that model.Comment: 4 pages including 3 figure

Status report on the folded tandem ion accelerator at BARC

The folded tandem ion accelerator (FOTIA) facility set up at BARC has become operational. At present, it is used for elemental analysis studies using the Rutherford backscattering technique. The beams of 1H, 7Li, 12C, 16O and 19F have been accelerated up to terminal voltages of about 3 MV and are available for experiments. The terminal voltage is stable within ±2 kV. In this paper, present status of the FOTIA and future plans are discussed

Excess energy of an ultracold Fermi gas in a trapped geometry

We have analytically explored finite size and interparticle interaction corrections to the average energy of a harmonically trapped Fermi gas below and above the Fermi temperature, and have obtained a better fitting for the excess energy reported by DeMarco and Jin [Science $\textbf{285}$, 1703 (1999)]. We have presented a perturbative calculation within a mean field approximation.Comment: 8 pages, 4 figures; Accepted in European Physical Journal

Field Diagnosis of Groundnut Diseases

Diseases ar e major constraints to groundnut production throughout the world. This handbook is designed to assist agricultural research and extension workers, wh o may have little formal training in plant pathology, to make tentative diagnosis of diseases of groundnut caused by 31 fungi, 2 bacteria. 9 viruses, a mycoplasma-like organism, 4 nematodes, and a parasitic flowering plant. The most characteristic field symptoms of each disease are Illustrated and descr ibed. It is emphasized that for confirmation of field diagnosi s the assistance of skilled plant pathologists will be requi red in most cases

Sudden switch of generalized Lieb-Robinson velocity in a transverse field Ising spin chain

The Lieb-Robinson theorem states that the speed at which the correlations between two distant nodes in a spin network can be built through local interactions has an upper bound, which is called the Lieb-Robinson velocity. Our central aim is to demonstrate how to observe the Lieb-Robinson velocity in an Ising spin chain with a strong transverse field. We adopt and compare four correlation measures for characterizing different types of correlations, which include correlation function, mutual information, quantum discord, and entanglement of formation. We prove that one of correlation functions shows a special behavior depending on the parity of the spin number. All the information-theoretical correlation measures demonstrate the existence of the Lieb-Robinson velocity. In particular, we find that there is a sudden switch of the Lieb-Robinson speed with the increasing of the number of spin

On the universality of the fluctuation-dissipation ratio in non-equilibrium critical dynamics

The two-time nonequilibrium correlation and response functions in 1D kinetic classical spin systems with non-conserved dynamics and quenched to their zero-temperature critical point are studied. The exact solution of the kinetic Ising model with Glauber dynamics for a wide class of initial states allows for an explicit test of the universality of the non-equilibrium limit fluctuation-dissipation ratio X_{\infty}. It is shown that the value of X_{\infty} depends on whether the initial state has finitely many domain walls or not and thus two distinct dynamic universality classes can be identified in this model. Generic 1D kinetic spin systems with non-conserved dynamics fall into the same universality classes as the kinetic Glauber-Ising model provided the dynamics is invariant under the C-symmetry of simultaneous spin and magnetic-field reversal. While C-symmetry is satisfied for magnetic systems, it need not be for lattice gases which may therefore display hitherto unexplored types of non-universal kinetics

The (co-)occurrence of problematic video gaming, substance use, and psychosocial problems in adolescents

Aims. The current study explored the nature of problematic (addictive) video gaming and the association with game type, psychosocial health, and substance use. Methods. Data were collected using a paper and pencil survey in the classroom setting. Three samples were aggregated to achieve a total sample of 8478 unique adolescents. Scales included measures of game use, game type, the Video game Addiction Test (VAT), depressive mood, negative self-esteem, loneliness, social anxiety, education performance, and use of cannabis, alcohol and nicotine (smoking). Results. Findings confirmed problematic gaming is most common amongst adolescent gamers who play multiplayer online games. Boys (60%) were more likely to play online games than girls (14%) and problematic gamers were more likely to be boys (5%) than girls (1%). High problematic gamers showed higher scores on depressive mood, loneliness, social anxiety, negative self-esteem, and self-reported lower school performance. Nicotine, alcohol, and cannabis using boys were almost twice more likely to report high PVG than non-users. Conclusions. It appears that online gaming in general is not necessarily associated with problems. However, problematic gamers do seem to play online games more often, and a small subgroup of gamers – specifically boys – showed lower psychosocial functioning and lower grades. Moreover, associations with alcohol, nicotine, and cannabis use are found. It would appear that problematic gaming is an undesirable problem for a small subgroup of gamers. The findings encourage further exploration of the role of psychoactive substance use in problematic gaming

Design and performance of a hybrid fast and thermal neutron detector

We report the characterization, calibration and performance of a custom-built hybrid detector consisting of BC501A liquid scintillator and BC702 scintillator for the detection of fast and thermal neutrons, respectively. Pulse Shape Discrimination techniques are developed to distinguish events due to gamma-rays, fast and thermal neutrons. Software analysis packages are developed to derive raw neutron energy spectra from measured proton recoil spectra. The validity is demonstrated through the reconstruction of the (AmBe)-Am-241(alpha,n) neutron spectrum. (C) 2017 Elsevier B. V. All rights reserved