Observations of comet Levy 1990c in the (OI) 6300-A line with an imaging Fabry-Perot

We have observed the comet Levy 1990c during 16-25 August 1990 using the MPAE focal reducer system based Fabry-Perot etalon coupled with the 1 meter telescope of the Observatory of Hoher List. The free spectral range and resolution limit of the interferometer was approximately 2.18 A and approximately 0.171 A respectively. Classical Fabry-Perot fringes were recorded on a CCD in the cometary (OI) 6300 A line. They are well resolved from telluric air glow and cometary NH2 emission. Our observations indicate that the (OI) is distributed asymmetrically with respect to the center of the comet. In this paper we report the spatial distribution of (OI) emission and its line width in the coma of comet Levy

Doppler velocities in the ion tail of comet Levy 1990c

We have obtained time alternating sequences of column density maps and Doppler velocity fields in the plasma tail of comet Levy 1990c. We describe the observing technique and data analysis, and we present first results

Visualisation of an entangled channel spin-1 system

Co-variance matrix formalism gives powerful entanglement criteria for continuous as well as finite dimensional systems. We use this formalism to study a mixed channel spin-1 system which is well known in nuclear reactions. A spin-j state can be visualized as being made up of 2j spinors which are represented by a constellation of 2j points on a Bloch sphere using Majorana construction. We extend this formalism to visualize an entangled mixed spin-1 system.Comment: 4 pages,4 figure

Study of Some Debris Avalanches in Garwal Himalaya, India

This study was carried out in the Alaknanda - Dhauliganga catchment area, located in the north and northeast of Joshimath in the Garfiwal Himalaya. The snow fields, cirques and the related glaciers are located above the altitude approximate 4000 meters, while the river valley have a mean altitude of around 2000 meters. The strategic roads viz. Joshimath-Badrinath and Joshimath-Nitipass pass through this area with a number of villages along with their cultivated land are located along the roads. These roads are often blocked on huge debris avalanches not only damage the road, but also the cultivated land and forests. The geological studies has indicated the presence of a major thrust viz, Main Central Thrust (M.C.T.) in this area, with highly deformed rocks. Most of the zones with frequent debris avalanches do not follow the thrust zones etc. The glaciers have been studied on the basis of aerial photographs and landset imageries. It appears although most of the glaciers are slowly receding back, are located in the crest of Badrinath is apparently static and many crevasses etc., are formed and slumping is taking place. The slumped mass of Ice is pushing the moraines down in the valley and large scale debris avalanches are causes on the Joshimath-Badrinath roa

Arbitrarily large families of spaces of the same volume

In any connected non-compact semi-simple Lie group without factors locally isomorphic to SL_2(R), there can be only finitely many lattices (up to isomorphism) of a given covolume. We show that there exist arbitrarily large families of pairwise non-isomorphic arithmetic lattices of the same covolume. We construct these lattices with the help of Bruhat-Tits theory, using Prasad's volume formula to control their covolumes.Comment: 9 pages. Syntax corrected; one reference adde

Environmental effects of SPS: The middle atmosphere

The heavy lift launch vehicle associated with the solar power satellite (SPS) would deposit in the upper atmosphere exhaust and reentry products which could modify the composition of the stratosphere, mesosphere, and lower ionosphere. In order to assess such effects, atmospheric model simulations were performed, especially considering a geographic zone centered at the launch and reentry latitudes

Pb(Ni1/3Sb2/3)O3-PbZrTiO3 Ceramic Sensors for Underwater Transducer Application

Cymbal is a class-V flextensional transducer that consists of thickness poled ceramic disc sandwiched between the two metal end caps which acts as a mechanical transformer. Cymbal transducers were fabricated using piezoceramic discs of compositions Pb0.988(Zr0.52Ti0.48) 0.976Nb0.024O3 (PZT type 5A) and Pb0.98La0.02 (NiSb)0.05[(Zr0.52 Ti0.48)0.995]0.95O3 (PNS-PZT). Piezoelectric and hydrostatic constants for PNS-PZT composition were on higher side. End capswere made up of brass sheet having thickness 0.5 mm. Underwater testing of the polyurethane moulded cymbal hydrophones were carried out in acoustic tank and compared. The resonance frequency for both the hydrophones was 10.1 kHz. PNS-PZT hydrophone shows higher sensitivity (-183.2 dB re 1V/μPa) compared to PZT type 5A (-191.2 dB re 1V/μPa) at resonance frequency. Directivity pattern observed for PNS-PZT is omni-directional near resonance frequency.Defence Science Journal, 2012, 62(4), pp.269-273, DOI:http://dx.doi.org/10.14429/dsj.62.171

A Monopole-Antimonopole Solution of the SU(2) Yang-Mills-Higgs Model

As shown by Taubes, in the Bogomol'nyi-Prasad-Sommerfield limit the SU(2) Yang-Mills-Higgs model possesses smooth finite energy solutions, which do not satisfy the first order Bogomol'nyi equations. We construct numerically such a non-Bogomol'nyi solution, corresponding to a monopole-antimonopole pair, and extend the construction to finite Higgs potential.Comment: 11 pages, including 4 eps figures, LaTex format using RevTe