• Volume 4, Issue 4

      April 1975,   pages  153-198

    • Orbit of the spectroscopic binary b Persei

      R Rajamohan M Parthasarathy

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      New spectroscopic orbital elements have been derived for the close binary system b Persei. The period is improved to 1.527360 days. Earlier observations by Cannon (1914), Harper (1930) and Heard (1938) have been reanalysed and the reality of the variations in the orbital elements is established. The change inω indicates an aspidal motion period of about 60 years. Changes in some of the orbital elements may be due to the distortion of the radial velocity curve by gas streams present in the system. In view of the flaring radio emission detected from this system and the variations of the orbital elements, we believe that the close binary system b Persei is in an active mass transfer phase.

    • Photoelectric photometry of the open cluster NGC 1778

      U C Joshi R Sagar P Pandey

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      PhotoelectricU, B, V magnitudes and colours for 48 stars in the open cluster NGC 1778 have been determined. The colour excess is$$0_ \cdot ^m 34$$, distance to the cluster 1062 pc, and apparent diameter of the cluster 4.5 minutes of arc. The age is estimated at 1.6×108 years.

    • Conformal invariance and scalar-tensor theories

      Eric A Lord

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      A new generalisation of Einstein’s theory is proposed which is invariant under conformal mappings. Two scalar fields are introduced in addition to the metric tensor field, so that two special choices of gauge are available for physical interpretation, the ‘Einstein gauge’ and the ‘atomic gauge’. The theory is not unique but contains two adjustable parameters ζ anda. Witha=1 the theory viewed from the atomic gauge is Brans-Dicke theory (ω=−3/2+ζ/4). Any other choice ofa leads to a creation-field theory. In particular the theory given by the choicea=−3 possesses a cosmological solution satisfying Dirac’s ‘large numbers’ hypothesis.

    • Thermal emission spectrum of MgI

      S N Puri Hari Mohan

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      Thermally excited emission spectrum of MgI, hitherto known only in flame and absorption sources, has been recorded in the spectral region λλ3668–4220, using a high temperature vacuum graphite tube furnace. The bands were classified into three new band systems in the wavelength regions λλ3905–4002, λλ3834–4079 and λλ3668–3888 along with a number of additional bands in the previously known system A, λλ3955–4220. The constants for the various systems are as follows:

    • Liquid mixture excess properties by the hard sphere model

      K Narasimha Swamy

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      The excess properties of mixing were calculated for seven systems Ar-CH4; Ar-N2; Ar-O2; Ar-CO; CO-CH4; O2-N2; N2-CO, using the Caranhan and Starling equation of state of rigid spheres and the Longuet-Higgins and Widom model. Two sets of calculations were done one using the experimentalGE to calculateSE,HE andVE, and the other making use of Miller’s cross parameter values. The calculated values are compared with those of Snider and Herrington and Miller’s values and also with the experimental values. The agreement was found to be good.

    • Anomalous absorption of intense electromagnetic radiation in a non-uniform overdense plasma

      S N Antani

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      In this work, we present numerical computation of anomalous absorption of a powerful electromagnetic wave incident normally, on an isothermal plasma with a linear density gradient. We consider first, the “intensity” dependence of anomalous absorption treating two important cases: one that of a typical high temperature, high density fusion plasma occurring in a laser-pellet application and the other that of an ionospheric (F-layer) plasma. It is found that for low incident powers, reflection is almost constant, corresponding essentially, to classical electronion collisions. As we increase the incident power, however, we find that the reflection starts dropping and the absorption takes over. This result is interpreted in terms of the instability generated anomalous absorption of the incident wave. Next, we consider the “wavelength” dependence of anomalous absorption, wherein we observe that the effect of anomalous absorption is increasing for longer wavelengths of the incident laser radiation.

    • SU(3)×SU(3) symmetry breaking, (8, 8) Model and theη→3π decay

      S R Roy R K Roychoudhury

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      It is shown that the (8, 8) model and explicitηπ0 mixing successfully explain theη→3π decay width whereas the decay width calculated from the mass difference$$m_{K^ + }^2 - m_{K^0 }^2 $$ is about one order less than the experimental value.

    • The structure of bis-(L-threonine) copper (II). H2O

      V Amirthalingam K V Muralidharan

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