Priyanka Pandey

Solid-liquid equilibrium, thermal, and physicochemical studies on salicylamide-4-nitrophenol and 2-cyanoacetamide-4- aminoacetophenone organic eutectic systems

The solid–liquid phase equilibrium data of two binary organic systems, namely, salicylamide–4-nitrophenol and 2-cyanoacetamide–4-aminoacetophenone show the formation of a eutectic in each case. The values of enthalpy of fusion of pure components and binary eutectics have been determined using differential scanning calorimeter (Mettler DSC-4000 system). The thermal properties of the materials, such as, heat of mixing, entropy of fusion, roughness parameter, interfacial energy, and excess thermodynamic functions were computed using the enthalpy of fusion values. The microstructures of eutectics were developed using unidirectional thermal gradient, and regions of interest for microstructures were photographed.

Physicochemical studies on organic eutectic and monotectic alloys

Phase diagram, growth kinetics, thermal behaviour and microstructure of a monotectic system involving a non-metal-non-metal binary organic analogue are discussed here. The eutectic, monotectic and consolute temperatures are: 87.1, 107.2 and 149.0°C respectively, at 0.968, 0.154 and 0.521 mole fractions of 1,4-dibromobenzene. The upper consolute temperature lies 41.8°C above the monotectic horizontal. Growth kinetics data of the pure and binary materials show the obeyence of Hillig-Turnbull equation. Enthalpy of fusion data obtained from Mettler DSC-4000 was used to calculate the heat of mixing, entropy of fusion, Jacksons roughness parameter, excess thermodynamic functions, interfacial energy and radius of critical nucleus. The optical microphotographs of the eutectic and monotectic show their characteristic features.

[Cu2(en)2(N3)4]n – A new member in the family of copper(II)-azido assemblies: structural and magnetic studies

Abstract A copper(II) complex with ethylene diamine and azide, viz., [Cu2(en)2(N3)4]n has been isolated under self-assembling conditions and characterized both structurally and magnetically in order to probe the role of reactant molar ratios in generating supramolecular assemblies with strong magnetic interactions toward achieving molecule-based magnets as a long-term objective. The title structure with ferromagnetic interactions is an intermediate member in the family of copper-azido assemblies involving ethylene diamine, obtained by systematic modifications in the reactant molar ratios, highlighting the inherent difficulty in controlling the final solid formation and potential of the delicate equilibrium conditions in directing supramolecular structures, which may display interesting structure-correlated properties. The structure is a chain of μ-1,1 bridged dimers of Cu2, connected to Cu1 through μ-1,3 azide bridges, leading to a rail-road arrangement of polymeric chains. Two such parallel chains are further linked to each other through Cu3, which is connected to Cu2′ of the dimer, through asymmetric end-on μ-1,1 azide bridges, resulting in a 2-D network in the unit cell. The magnetic behavior revealed ferromagnetic interactions in Cu(II) pairs and is dominated by overall antiferromagnetic interactions within the network.

Phase Diagram and Growth Behaviour of Durene–resorcinol System

Phase diagram of durene–resorcinol system, determined by the thaw-melt method, shows the formation of a monotectic (0.109 mole fraction of durene) and an eutectic (0.964 mole fraction of durene) with a large liquid miscibility gap in the region from 0.109 to 0.964 mole fraction of durene. The eutectic, monotectic and consolute temperatures are 78.4, 107.8 and 165.0°C, respectively. The growth behaviour studied by measuring the linear velocity of crystallization (v) in a capillary at different undercoolings (ΔT) suggests that the data obey the Hillig–Turnbull equation,v=u(ΔT)n, where u and n are constants depending on the nature of materials involved. From the values of enthalpy of fusion of the pure components, the eutectic and the monotectic determined by the DSC method using Mettler DSC-4000 system, entropy of fusion, enthalpy of mixing, Jackson’sroughness parameter, size of the critical nucleus interfacial energy and excess thermodynamic functions were calculated. The microstructures of the eutectic, and the monotectic, determined by the Leitz Laborlux D optical microscope show their characteristic features.

Effects of Rhizobium, PSB Inoculation and Phosphorus Management on Soil Nutrient Status and Performance of Cowpea in Acid Soil of Arunachal Pradesh, India

Cowpea [Vigna unguiculata (L.) Walp.] is an important legume vegetable crop as well as pulse grown in India. It is warm season crop of humid tropics and sub tropical zones, well adapted to many areas of the country including North East India. It has manifold uses such as vegetable, pulse, green manuring and fodder crop (Singh et al., 2012). Cowpea leaves and green pods are consumed as vegetable and the dried grain is used in many different food preparations. In India, cowpea is grown on about 0.5 million ha with an average productivity of 600 to 750 kg grains/ha (Meena et al., 2010). Yield potential of cowpea can be exploited by the application of adequate amount of nutrients required by the legumes.