Browsing by Author "S.K. Tolpadi"

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Characteristics of waveguides filled with homogenous lossy anisotropic drifting plasma
(1973) Dinesh Singh; S.K. Tolpadi
In this paper the dispersion relation for rectangular waveguides filled with homogeneous lossy drifting plasma under the influence of infinite longitudinal magnetic field is derived and discussed. The properties of TE modes are found to be the same as those of air-filled guides. However, uniaxial anisotropic drifting lossy plasma has a significant effect on the propagation characteristics of TM modes. A comparison of the effects and physical significance of the changes due to isotropic and anisotropic plasma models is discussed. © 1973 Taylor & Francis Group, LLC.
Collision frequency effect on plasma-filled transversely magnetized rectangular waveguide characteristics
(1972) Dinesh Singh; P.N. Gupta; S.K. Tolpadi
The characteristics of a rectangular waveguide filled with homogeneous lossy plasma in the presence of a strong magnetic field are discussed. The B-ω curves are drawn from the dispersion relation for different values of collision frequency and the results are compared with the characteristics of transversely magnetized plasma-filled rectangular waveguides without including the effect of collisions. It is found that the effect of the collision frequency is that the non-propagating region is limited to a point dependent on wave-number in the direction of the magnetic field and independent of values of collision frequency. © 1972 Taylor and Francis Group, LLC.
Comparison of electron temperature with thermosphere probe data [5]
(1966) R.N. Singh; S.K. Tolpadi
[No abstract available]
Correction to “Dispersion Relations for Parallel-Plane Waveguide Containing Transversely Magnetized Uniaxial and Warm Plasma in Relative Motion”
(1976) G.N. Tiwari; Dinesh Singh; S.K. Tolpadi
[No abstract available]
Dispersion Relations for Parallel-Plane Waveguide Containing Transversely Magnetized Uniaxial and Warm Plasma in Relative Motion
(1973) P.K. Jain; Dinesh Singh; P.N. Gupta; S.K. Tolpadi
Starting from the dispersion relation corresponding to TM modes in the rest system and relativistic transformations, dispersion relation corresponding to TM mode, is derived in the moving system. The plasma is assumed to be homogeneous, compressible, and uniaxial in the presence of strong TM field. From the wave equation corresponding to TE modes in the moving system, it is concluded that the dispersion relation corresponding to TE modes is independent of the temperature of plasma and is the same as that for ordinary air-filled parallel-plane waveguide in the presence of strong TM field. The magnetic field has no effect on air filled guide. The dispersion relation corresponding to TEM modes is also derived. © 1973, IEEE. All rights reserved.
Experimental studies on the ionic (protonic) transport in ammonium para-tungstate pentahydrate
(1989) S. Chandra; S.K. Tolpadi; S.A. Hashmi
Proton transport in ammonium para-tungstate pentahydrate (NH 4)10W12O41.5H2O (APT.5H2O) has been established using coulometry transient ionic current IR and electrical conductivity measurements along with the TGA/DTA results of Kiss and co-workers. The mobile ions are NH4+, H+ and O2-. The ions (H+ and O2-) are the products of electrolysis of the inter-layer water. The temperature dependence of the electrical conductivity has been correlated with the accompanying dehydration and de-ammoniation reaction of APT.5H2O.
Magnetic field of the F-region from h'-f records
(1962) R.N. Singh; S.K. Tolpadi
[No abstract available]
Proton transport in Ammonium Para Tungstate (NH4)10W12O41.5H2O
(1986) S.K. Tolpadi; S. Chandra; S.A. Hashmi
The possibility of Ammonium Para Tungstate as a proton conductor has been explored. The temperature dependence of the electrical conductivity has been studied in the temperature range 308 K to 473 K at 100 KHz. It has been interpreted in terms of possible structural change and thermal dehydration as evidenced in TGA studies. The ionic transport is shown to be due to (a) H+ ion motion through the chain of interlayer H2O-H2O bondage (b) H+ ion hopping through NH4 ions (c) O2- motion obtained by the electrolysis of interlayered water. Coulometry or d-c electrolysis provides a direct proof of (c). The IR studies also support some of the above conclusion. © 1986.
Relatistic Effect On Guided Wave Propagation Through Isotropic Lossy Plasma
(1976) G.N. Tiwari; Dinesh Singh; S.K. Tolpadi
The dispersion relations and cutoff frequencies for the appropriate modes existing inside the relativistically moving lossy isotropic plasma waveguide are studied and are found to depend on waveguide dimensions, plasma-parameters and the drift velocity of plasma medium. The field as well as power flow are also studied in detail and it is found that the fields as well as power flow for TE modes are unchanged while for TM modes they are modified depending on the drift velocity of the plasma medium. The results are compared with those obtained for the case of lossless relativistically moving and lossy stationary plasma waveguides. Copyright © 1976 by The Institute of Electrical and Electronics Engineers, Inc.
Reply to comments on ‘Characteristics of waveguides filled with homogeneous lossy anisotropic drifting plasma’
(1975) Dinesh Singh; S.K. Tolpadi
[No abstract available]
Transient ionic current measurement of ionic mobilities in a few proton conductors
(1988) S. Chandra; S.K. Tolpadi; S.A. Hashmi
The aim of this paper is (a) to detect the number of mobile ionic species in some proton conductors, and (b) to evaluate their mobility. A transient ionic current measurement technique was used on the proton conductors viz. N2H6SO4, N2H6Cl2, (NH4)10W12O41·5H2O and MoO3·2H2O for the above purpose. © 1988 Elsevier Science Publishers B.V. (North-Holland Physics Publishing Division).