Papers

The variation of drift and anisotropy parameters of Ionospheric irregularities in the E-region at Waltair (dip 17.7oN; 83.3o E) during 3 geomagnetic storms has been studied mainly to resolve the controversy that has been reported in the literature about the effect of magnetic activity on the drift and anisotropy parameters. E-region spaced antenna drift records taken on frequency 2.4 MHz during the period September 1983-May 1984 at Waltair are used in the present study. In the E-region, the true drift velocity during storm period appears to be larger than the control day values. The ratio of Va/V shows a gradual decrease during storm period and random velocity during storm time is quiet less compared to the control day values. No significant variation is observed in the apparent drift direction and structure size on storm days with respect to the control days. The orientation of the semi-major axis mostly lies in the range of 120o – 150o N of E, both on storm days as well as on control days but the average value of the axial ratio shows a higher value compared to the average on control days.

ZnO nanoparticles and ZnO/CdS Core/Shell heterostructures have been prepared in the two-step hydrothermal method by using Starch as a capping agent. The tunability of the optoelectronic properties of ZnO/CdS can enhance the exciton life time. These type of Core/Shell nanostructures are coming under Type-II band alignment. The thickness of the shell CdS is varied, keeping the core ZnO nanopins are in the same sizes. The absorption and luminescence properties of ZnO/CdS Core/Shells are well studied. The longer exciton life time of these Type-II Core/Shell nanostructure could be beneficial for the potential application in Photosensor.

We have investigated Bianchi Type V stiff fluid cosmological model with variable gravitational and cosmological constant. To get the exact solution it is assumed that equation of state is P = p – 3  H, =p, where  = 0 h, p is the isotropic pressure,  is the coefficient of shear viscosity, H the Hubble constant, 0 and h are taken as constants. A, B and C are assumed as the functions of cosmic time t using power law relation. Some other physical and geometrical aspects of the model are also discussed in terms of cosmic time t.

The Cosmological principle is the hypothesis that the universe is spatially homogeneous and isotropic. In the study of cosmological model, the Einstein field equations and construct a static model of the universe. A method has proposed by Berman 1991 3 on the basis of the conservation law, to incorporate the variable Gravitational constant ‘G ’ and Cosmological constant ‘  ’ in the Einstein field equations. The solutions are obtained by choosing suitable values for the constant  and  , a number of cosmological models may be constructed and the validity of these models may be tested on the theoretical and observational grounds.

In this paper, the design and simulation of cylindrical, co-axial, Carbon Nanotube Field Effect Transistor (CNTFET) is presented using online Fettoy tool of Nanohub. This tool can provide various characteristics of CNTFET, like transfer characteristics, output characteristics, average velocity vs. gate voltage etc. To simulate the CNTFET we have considered the value of diameter of carbon nanotube 1nm which is of (13,0) chirality. Gate insulator thickness is taken as 1.5nm and the dielectic constant of the material used as gate oxide is k=20 , which is the value shown by ZrO2.

A comparison between designed CNTFET and conventional MOSFET shows improvement of various parameters which plays a significant role in design of logic circuits. With these improved properties of CNTFETs it can be concluded that it is very useful in designing of reversible logic circuits. Also, it is very efficient in terms of power consumption, speed of operations, and leakage current over conventional MOSFETs

The present paper deals with the study of amino acids and lipid concentration in the immature and mature oocyte in the fish Heteropneustes fossilis .It was observed that the essential amino acids under the influence of gonadotrophins play a vital role in the gonadal maturation as well as in the synthesis of various enzymes needed for steroidogenesis. In the present study, the rate of incorporation of amino acids and their transformation in gonads indicate their vital role in the maturation of gonads. In addition to amino acids, the lipid fraction especially the ester cholesterol and the phospholipid were also found to play a significant role during the sequential changes which occur during maturation process of the gonads of Heteropneustes fossilis.

The extreme efforts have been developed to design novel compounds to strains of resistant microorganisms. On-going search for novel and amazing drug delivery systems is primarily impact of the wellestablished fact that the convectional dosages are not sufficiently effective in conveying the drug compounds to its site of action and this has required the need to search for more efficient drugs. New five metal complexes of Nickel(II), Copper(II), Zinc(II), Cadmium(II) and Tin(II) with Schiff base ligand 4-(Benzylidene-amino)- 5- pyridin-4-yl-4H-[1,2,4] triazole-3-thiol were synthesized in ethyl alcohol as a solvent. The Synthesized compounds were characterized by different physicochemical techniques such as, elemental analysis C.H.N.S, FT-IR, UVvisible spectrophotometry, 1H NMR, conductivity and magnetic susceptibility measurements melting point, flame atomic absorption. The Schiff base ligand act as bidentate and coordinated to the metal atoms via the azomethine-N and S atom of thiol group. From the spectral studies, square planar geometry was proposed for the copper complex. The other complexes were proposed to be tetrahedral.

It is observed that every finite group is isometric to the group of Automorphisms of some Compact Riemann surface of genus 􀝃(≥ 2). Also found that the group of symmetries of a non-linear molecule (point group) is an excellent example of finite groups. In this paper we have considered the point group of Sulphur molecule S8 , which is a group of order 16. Then we prove that the bounds of the order of symmetry group of Automorphisms of Compact Riemann Surface on which the point group of S8 acts as a group of Automorphism is 4(g1), and the corresponding minimum value of g is 5, associated Fuchsian Group of signature is (2,2,2,2,2).

In this paper, a two warehouses inventory model with stock-dependent demand has been studied. In case there is limited capacity of the owned warehouse (OW), another warehouse is used named rented warehouse (RW) for large ordered quantity. The deterioration rate of inventory items is different in both the warehouses. In the case of OW, we allow for shortages and consider the time dependent backlogging rate. To achieve the optimal ordered quantity and the optimal interval for the total inventory cost, a solution procedure is established and it concludes the developed model with further extended environments.