Papers

Effects of overtaking disturbances behind the flow in CCW^1-3 approach have been included to describe the motion of cylindrical hydromagnetic shock wave in a self-gravitating rotating gas. The magnetic filed is assumed to have only constant axial (H_Zo = constant) and variable azimuthal (H_qo = r^1/2 H_z) components, taking an initial density distribution as r₀ = r'e^-lr, where r' is the density on the axis of symmetry and l is a non-dimensionalising constant. Cases of reverse trends of variation of flow variables with inclusion of e.o.d have been highlighted. 
 

A method involving the use of paper electrophoresis is described for the study of equilibria in mixed-ligand complex systems in solution. The technique is based on the movement of a spot of metal ion under an electric field with the complexants added to the background electrolyte at pH 8.5. The stability constants of the complexes were found to be 5.65, 5.25, 4.37, 3.83, 3.75, 3.61) for (Cu (II), UO₂ (II), Co (II), Zn (II), Cd (II) complexes, respectively, at µ = 0.1 and 35^oC.

Expanding energy as a function of volume in a Taylor series and using different order Pade'approximants, various equations of states have been obtained which have been combined with quasi-harmonic approximation for free energy to study the compression of BaS crystals at high pressures (up to 80 kbar). The results obtained are reasonaly good, lending support to the equations of state and the method used to extend their applicability.
 

A recent technique involving the use of paper electrophoresis is described for the study of the equilibria in binary complex systems in solution. The stability constants of ML and ML₂ complex species of some ions Cu (II)/ UO₂(II)/ Ni(II)/ Co(II)/ Zn(II)/ Cd (II) with Taurine were determined at an ionic strength of 0.1 perchloric acid and 35ºC. The stability constant of the ML and ML₂ complexes of metal - Taurine have been found to be (6.75, 5.89), (7.87, 5.10), (5.81, 3.69), (4.35, 3.58), (4.35, 3.30) and (4.31, 3.89) for Cu (II), UO₂(II), Ni(II), Co(II), Zn(II), Cd (II) complexes respectively.

A sample relation is used to calculate the ionicity (fi) and microhardness of binary tetrahedral semiconductors. An investigation into various crystal parameters and their correlation have been done. Lavin's modification of Phillip and Van Vechten (PVV) theory are discussed and hence ionic gap (E_c), homopolar gap (E_h) average gap (E_p) and ionicity (f_i) are investigated for binary tetrahedral semiconductors. The estimated value of ionicity is then used to evaluate the values of microhardness. The results have been compared with corresponding values reported in literature. A fairly good agreement has been obtained between the results and values reported by other workers.
 

This paper presents the finite element method to determine the temperature profile within the volume of the material during laser cutting of 304 grade stainless steel. The commercially available ANSYS software is used to find the solution for the finite element analysis. The results of the study showed that the temperature distribution is confined to a small region which is in agreement with the theoretical predictions.
 

In this paper, a new method of construction of modified second order slope rotatable designs with equi-spaced levels using pairwise balanced designs is suggested. The proposed method may sometimes lead to designs with less number of design points than those available in the literature. A table is provided where for a range of different values of v (v-stands for number of factors) the design points needed by different methods are compared for .
 

The demand for water has increased manifold due to population explosion and consequent increase in irrigation and industrial development. As the surface water resources are limited and mainly depend on monsoon, the increased water demand is being sustained by ground water source through many new tube wells tapping deeper aquifers. Vanur block is underlain by Coastal Alluvium, Cuddalore Sandstone, Vanur Sandstone, Limestone and Charnockite. The Vanur Sandstone is one of the main aquifers in the area and is the source for irrigation as well as for drinking water supply to Tindivanam town. The increased extraction of ground water has resulted in a steep decline of ground water levels.
An attempt has been made in this paper to study the long term behavior of ground water levels in this aquifer using the historical water level data collected from the observation wells being monitored by Auroville water service (Harvest) and Central Ground Water Board. The analysis of water level data indicates a long-term decline in the major part of the area. The result of the study indicates that urgent steps including strict regulatory meseaures on ground water extraction and augmentation of ground water resources through suitable artificial recharge structures may have to be initiated in the area to ensure sustainability of ground water extraction structures and to prevent possible saline water ingress.

India is veritable emporium of medicinal plants. A large number of different plant species contain natural pesticidal and medicinal value. The objective of this study was to determine the paradoxical nature of M. spicata. The studies have been undertaken on the life cycle, growth and mortality of T. confusum in rice grain. The survival rate of beetle is significantly reduced in the grain with increasing day and dose in extract of leaves of M. spicata. These plant extract was analyzed for certain trace metal viz. copper, zinc, manganese and iron. Concentrations of these metals in plant extract were iron (92 mg/g), copper (125 mg/g), zinc (122 mg/g) and manganese (31 mg/g).
 

The role of medicinal plants as primary tools in the maintenance of health as well as prevention and management of diseases is realized with alarming concern in recent days. The present study was undertaken to elucidate the property of some medicinal plants used in the treatment of diabeties mellitus and antioxidant related problems. There are many plants having compounds showing antidiabetic and antioxidant activity in their extracts. An attempt has been made to isolate the compounds responsible for the antidiabetic as well as antibiotic activity. This involves the extraction of the leaves from the plants Cassia auriculata and Moringa oleifera. The experimental observations made showed that there was a significant decrease in the sugar levels after the administration of the plant extracts indicating that the plants used in the present study contain antidiabetic and antioxidant factors which can bring out the hypoglycemic effect.