Vishwakarma J.P.,rakhpur University |
Nath G.,National Institute of Technology Raipur
Physica Scripta | Year: 2010
A self-similar solution for the propagation of a cylindrical shock wave in a dusty gas with heat conduction and radiation heat flux, which is rotating about the axis of symmetry, is investigated. The shock is assumed to be driven out by a piston (an inner expanding surface) and the dusty gas is assumed to be a mixture of non-ideal gas and small solid particles. The density of the ambient medium is assumed to be constant. The heat conduction is expressed in terms of Fourier's law and radiation is considered to be of diffusion type for an optically thick grey gas model. The thermal conductivity K and the absorption coefficient αR are assumed to vary with temperature and density. Similarity solutions are obtained, and the effects of variation of the parameter of non-idealness of the gas in the mixture, the mass concentration of solid particles and the ratio of density of solid particles to the initial density of the gas are investigated. © 2010 The Royal Swedish Academy of Sciences.
Joshi D.,Jiwaji University |
Mittal D.,Jiwaji University |
Shrivastav S.,Jiwaji University |
Shukla S.,Jiwaji University |
Srivastav A.K.,rakhpur University
Archives of Environmental Contamination and Toxicology | Year: 2011
Mercury (Hg), widely used in industry, is a great environmental health problem for humans and animals. Despite several reports regarding Hg toxicity, there is scarcity of data on its toxic manifestations on Sprague Dawley rats under realistic exposure conditions. Experimental studies have shown that sulphur-containing antioxidants have beneficial effects against the detrimental properties of Hg. The present work was aimed to study the therapeutic potential of combined administration of N-acetyl cysteine (NAC; 2 mmol/kg ip), zinc (Zn; 2 mmol/kg po), and selenium (Se; 0.5 mg/kg po) against dimethylmercury (DMM; 1 mg/kg po)-intoxicated male rats for 12 weeks. Exposure to DMM caused significant alterations in cytochrome P450 (CYP) activity, microsomal lipid peroxidation, and proteins. Activities of transaminases (aspartate aminotransferase/alanine aminotransferase), alkaline phosphatase, and lactate dehydrogenase in serum, as well as activities of CYP enzymes aniline hydroxylase (AH), amidopyrine-N- demethylase (AND) in liver microsomes and activities of acid phosphatase, alkaline phosphatase, glucose-6-phophatase, and succinic dehydrogenase in the liver and kidney, were significantly altered after DMM administration. DMM exposure also induced severe hepato-renal alterations at the histopathological level. NAC, along with Zn and Se, dramatically reversed the alterations in all of the variables more toward control. The study results conclude that protective intervention of combined treatment of NAC, along with Zn and Se, is beneficial in attenuating DMM-induced systemic toxicity. © 2011 Springer Science+Business Media, LLC.
Botet R.S.,French National Center for Scientific Research |
Rai R.K.,rakhpur University
Earth, Planets and Space | Year: 2013
We present optical features characteristic of the shape of composite dust particles, such as grain-aggregates formed under cosmic or atmospheric conditions. The discussion develops along two examples of realistic models for the formation of the composite particles, and constant refractive indices. That way, particular features exhibited in the optical cross section behaviors result from the particle structure only. The role of the ratio between optical particle cross section and the corresponding cross section of the coated sphere of same composition and volume is highlighted. Limited wavelength ranges are defined where the coated sphere model can be used to obtain the effective radius or the volume composition of the particle. Other wavelength domains are very dependent on the particle formation mechanisms, then giving constraints on the possible formation processes. Therefore, such an approach is able to provide inverse methods to obtain the actual values of physical parameters from definite features of optical quantities. © The Society of Geomagnetism and Earth, Planetary and Space Sciences (SGEPSS);.
Singh G.,rakhpur University |
Sengupta S.K.,rakhpur University |
Kapoor I.P.S.,rakhpur University |
Dubey S.,rakhpur University |
And 2 more authors.
Journal of Energetic Materials | Year: 2013
Four transition metal nanoparticles (TMNs) of 3d series (Cu, Co, Ni, and Fe) were prepared by hydrazine reduction of metal chloride in ethylene glycol at 60°C and characterized by X-ray diffraction (XRD). The XRD pattern showed average particle sizes for Cu, Ni, Co, and Fe of 16.7, 40.5, 27.4, and 35.0 nm, respectively. The activity of these TMN accelerants on the thermal decomposition of ammonium perchlorate (AP) was investigated using thermogravimetry (TG), differential scanning calorimetry (DSC), and ignition delay studies. Isothermal TG data were used to evaluate the kinetic parameters by model fitting as well as an isoconversional methods. The activation energy for thermal decomposition of AP was found to be 66.8, 68.7, 78.5, and 85.4 kJmol-1, respectively, for Co, Cu, Ni, and Fe, when they were mixed with AP. Hence, the order of activity was found to be Co > Cu > Ni > Fe. The accelerant effect of nanoparticles of TMNs was found to be better than their respective nano-oxides. © 2013 Copyright Taylor and Francis Group, LLC.
Yadav A.K.,Anand Engineering College |
Yadav L.,rakhpur University
International Journal of Theoretical Physics | Year: 2011
The Bianchi type III dark energy model with constant deceleration parameter is investigated. The equation of state parameter ω is found to be time dependent and its existing range for this model is consistent with the recent observations of SN Ia data, SN Ia data (with CMBR anisotropy) and galaxy clustering statistics. The physical aspects of the dark energy models is discussed. © 2010 Springer Science+Business Media, LLC.
Yadav V.K.,rakhpur University |
Yadav L.,rakhpur University
Romanian Reports of Physics | Year: 2013
Some anisotropic locally rotationally symmetric (LRS) bulk viscous magnetized Bianchi type-I string cosmological models are studied in context of Lyra's geometry. The modified Einstein's field equations have been solved by taking a physically valuable condition that shear scalar (σ) is proportional to the scalar expansion (θ) which leads to A = aBn. This general solution in terms of metric potential (B) describe the characteristic of string Universe in presence of bulk viscosity and magnetic field. The study reveals that the coefficient of viscosity decreases uniformly with cosmic expansion during evolution of universe. In absence of magnetic field, the model can exit during the a span of time and the energy conditions can be fulfilled for a finite interval of time due to presence of bulk viscosity. It has been found that the displacement vector (β) is a decreasing function of time and it approaches to small positive value at late time, which is collaborated with Halford (Aust. J. Phys. 23, 863, 1970) as well as recent observations of SN Ia. The physical behavior of derived models are also described.
Singh R.P.,St Andrews College |
Yadav L.,rakhpur University
Romanian Reports in Physics | Year: 2011
A new class of a spatially homogeneous and anisotropic Bianchi type-V cosmological models of the Universe for bulk viscous fluid distribution within the framework of general relativity is investigated by applying the law of variation for the generalized mean Hubble's parameter that yields a constant value of deceleration parameter. The variation for Hubble's parameter generates two types of solutions for the average scale factor one is of power-law type and other is of the exponential form. Using these two forms, Einstein's field equations are solved separately that correspond to singular and non-singular models of the Universe respectively. It is observed that for positive value of deceleration parameter q of the Universe decelerates whereas for negative value of q the Universe accelerates. Expressions for look-back time-redshift, neoclassical tests (proper distance d(z)), luminosity distance red-shift and event horizon are derived and their significance are described in detail. Some physical and geometrical properties of the models are also discussed.
Singh R.S.,rakhpur University |
Prakash H.,Allahabad University
Physical Review A - Atomic, Molecular, and Optical Physics | Year: 2013
The classical definition of degree of polarization (DOP) is expressed in the quantum domain by replacing intensities through quantum mechanical average values of relevant number operators and is viewed as the first generalization of intensity. This definition assigns inaccurately the unpolarized status to some typical optical fields, e.g., amplitude-coherent phase-randomized and hidden-polarized light, which are not truly unpolarized light. The apparent paradoxical trait is circumvented by proposing a new definition of DOP in quantum optics through the second generalization of intensity. The correspondence of a new DOP to the usual DOP in quantum optics is established. It is seen that the two definitions disagree significantly for intense optical fields but coincide for weak light (thermal light) or for optical fields in which occupancy of photons in the orthogonal mode is very feeble. Our proposed definition of DOP, similar to other proposals in literature, reveals an interesting feature that states of polarization of optical quantum fields depend upon the average photons (intensity) present therein. © 2013 American Physical Society.
Shukla H.S.,rakhpur University |
Verma R.,rakhpur University
International Journal of Applied Engineering Research | Year: 2016
Recognition of people is a big challenging problem. Face recognition is one of them and up to date. Face recognition is a task that humans perform routinely in our daily lives. The large availability of powerful and low-cost and embedded computing systems is created. Automatic processing of digital images in a number of applications, including biometric authentication, surveillance, human computer interaction, and multimedia management. Implementation in automatic face recognition follows naturally. The face recognition technique has several advantages over other biometric modalities such as fingerprint and iris: besides being natural and nonintrusive, the most important advantage of face is that it can be captured at a distance and in a covert manner. In this paper, we proposed multilevel technique for human face recognition and we use the neural network techniques to train the data. In the last we evaluate the performance rate and compared to existing techniques. © 2016, Research India Publications.
Kumar R.,rakhpur University |
Srivastava S.K.,rakhpur University
International Journal of Geometric Methods in Modern Physics | Year: 2014
In General Relativity, the electric (Eαβ) and magnetic (Hαβ) parts of Weyl tensor are the gravitational quantities that play an analogous role to the electric and magnetic fields in classical electromagnetism. The present study deals with Bianchi type VI 0 cosmological model with purely magnetic (PM) and purely electric (PE) space time. Conditions of PM (PE) solutions satisfy E αβ = 0, Hαβ ≠ 0 (H αβ = 0, Eαβ≠ 0). We present a new class of cosmological model with PM and PE solutions when the source of gravitation is perfectly fluid. Some physical and geometrical properties of the models are also discussed. © World Scientific Publishing Company.