Electronic structure and magnetism in the frustrated antiferromagnet LiCrO2

LiCrO2 is a 2D triangular antiferromagnet, isostructural with the common battery material LiCoO2 and a well-known Jahn-Teller antiferromagnet NaNiO2. As opposed to the latter, LiCrO2 exibits antiferromagnetic exchange in Cr planes, which has been ascribed to direct Cr-Cr d-d overlap. Using LDA and LDA+U first principles calculations I confirm this conjecture and show that (a) direct d-d overlap is indeed enhanced compared to isostructural Ni and Cr compounds, (b) p-d charge transfer gap is also enhanced, thus suppressing the ferromagnetic superexchange, (c) the calculated magnetic Hamiltonian maps well onto the nearest neighbors Heisenberg exchange model and (d) interplanar inteaction is antiferromagnetic.Comment: 5 pages, 4 figure

The pressure-amorphized state in zirconium tungstate: a precursor to decomposition

In contrast to widely accepted view that pressure-induced amorphization arises due to kinetic hindrance of equilibrium phase transitions, here we provide evidence that the metastable pressure-amorphized state in zirconium tungstate is a precursor to decomposition of the compound into a mixture of simple oxides. This is from the volume collapse ΔV across amorphization, which is obtained for the first time by measuring linear dimensions of irreversibly amorphized samples during their recovery to the original cubic phase upon isochronal annealing up to 1000 K. The anomalously large ΔV of 25.7 ± 1.2% being the same as that expected for the decomposition indicates that this amorphous state is probably a precursor to kinetically hindered decomposition. A P–T diagram of the compound is also proposed

A New Subclass of Meromorphic Starlike Functions Associated with Q-Hypergeometric Functions

The fractional calculus operator has used in various field of sciences, GFT and in the engineering, if we extend the ordinary fractional calculus in the q-theory we get fractional q-calculus operator. In this paper by making use of fractional q-calculus operator we have introduced a new subclass of Meromorphic starlike functions N_q (? ,? ,?) defined in the open disk and determined coefficient estimate, neighbourhood result, subordination results, extreme points and partial sums for the functions belonging to this class

Off-Grid Energy Technologies Used in Rural Areas of India

Energy scenario in India is changing with a greater pace. Growth rate of villages has increased, likewise their energy demand. With the awareness of the decreasing natural resources, non conventional energy resources are gaining lots of interest in sparsely separated areas. The rural areas of India are having the huge scarcity of energy because of limited energy resources and Grid connectivity is not feasible due to economic factors and geographical situations. So we require to establish the off grid system for the benefit of the mass. Off-grid System's commissioning and operation done as indigenous unit, and free from grid related problems like frequency and voltage regulations and they provides flexible operation because their emphasis is on extraction of energy and conversion into useful work. This paper discusses the potential use of off-grid energy technologies as an alternative for grid extension. Off-grid Energy systems provide the solutions to the basic energy needs in the rural areas of India. These indigenously build plants are not connected to any electrical utility and can be connected with the micro grid for the better reliable operation. Due to small size their demand and load management would be easy. Off-grid system utilizes the solar thermal radiation, wind energy, geothermal energy, tidal wave, Biomass etc. There is numerous numbers of applications where we can use this energy and decrease the dependence on conventional grid