A K Shukla
Articles written in Pramana – Journal of Physics
Volume 40 Issue 2 February 1993 pp 81-87
Internal pressure, ultrasonic velocity and viscosity of multi-component liquid systems
J D Pandey A K Shukla Neelima Tripathi G P Dubey
Ultrasonic velocity, density and viscosity were measured in two ternary liquid systems namely,
Volume 43 Issue 5 November 1994 pp 353-360
Sound velocity in binary liquid mixtures and the statistical mechanical theories
J D Pandey Shikha A K Shukla Anil K Singh
Sound velocity in three binary liquid mixtures benzene+cyclohexane (I), cyclohexane+carbontetrachloride (II) and benzene+carbontetrachloride (III) has been measured. Significant structure and Flory — Patterson theories have been employed to evaluate ultrasonic velocity in the systems. The values are in good agreement with the experimental ones. A comparative study of significant structure theory and Flory-Patterson Theory has been made. Both the theories give satisfactory results for the three liquid mixtures.
Volume 67 Issue 2 August 2006 pp 395-400 Brief Reports
Metallic/semiconducting ratio of carbon nanotubes in a bundle prepared using CVD technique
Khurshed Ahmad Shah S S Islam H S Mavi A K Shukla Harsh
We present an investigation of the nature of single-walled carbon nanotubes (SWCNTs) in a bundle by resonant Raman spectroscopy. The calculation has been done for the three peak positions in radial breathing mode (RBM) spectra obtained by using a laser excitation wavelength (γ) of 633 nm from He-Ne laser on SWNT bundle sample prepared by chemical vapor deposition (CVD) technique using iron catalyst at 800°C. The detailed analysis in the present study is focused on peak positions 162 cm^{−1}, 186 cm^{−1}, and 216 cm^{−1}. The firs step of the analysis is to construct a list of possible (
Volume 88 Issue 4 April 2017 Article ID 0061 Research Article
R CHAUBEY A K SHUKLA RAKESH RAUSHAN
The general class of Bianchi cosmological models with dark energy in the form of modified Chaplygin gas with variable $\Lambda$ and $G$ and bulk viscosity have been considered. We discuss three types of average scalefactor by using a special law for deceleration parameter which is linear in time with negative slope. The exact solutions to the corresponding field equations are obtained. We obtain the solution of bulk viscosity ($\xi$ ), cosmologicalconstant ($\Lambda$), gravitational parameter ($G$) and deceleration parameter ($q$) for different equations of state. The model describes an accelerating Universe for large value of time $t$ , wherein the effective negative pressure induced by Chaplygin gas and bulk viscous pressure are driving the acceleration.
Volume 88 Issue 4 April 2017 Article ID 0065 Research Article
The anisotropic cosmological models in $f (R, T)$ gravity with $\Lambda (T)$
The general class of anisotropic Bianchi cosmological models in $f(R, T)$ modified theories of gravity with $\Lambda (T)$ has been considered. This paper deals with $f(R, T)$ modified theories of gravity, where the gravitational Lagrangian is given by an arbitrary function of Ricci scalar $R$ and the trace of the stress-energy tensor $T$ has been investigated for a specific choice of $f (R,T )$ = $f_{1}(R) + f_{2}(T)$. The exact solutions to the corresponding field equations are obtained in quadrature form. We have discussed three types of solutions of the average scale factor for the general class of Bianchi cosmological models by using a special law for deceleration parameter which is linear in time with a negative slope. The solutions to the Einstein field equations are obtained for three differentphysical viable cosmologies. All physical parameters are calculated and discussed in each model.
Volume 92 Issue 5 May 2019 Article ID 0079 Research Article
RAKESH RAUSHAN A K SHUKLA R CHAUBEY T SINGH
In this paper, we have studied the locally rotationally symmetric (LRS) Bianchi type-I cosmological model filled with a bulk viscous cosmological fluid in $f(R)$ gravity in the presence of time-varying gravitational and cosmological constant. We have used the power-law and intermediate scenario for scale factor to obtain thesolution of the field equations. The evolution of temperature of a viscous Universe is also analysed.
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Volume 93 | Issue 5
November 2019
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