Anomalous magnetoresistance in high-temperature organic-based magnetic seminconducting V(TCNE)x films

Journal ArticleAnomalous positive magnetoresistance (MR) in high temperature organic-based magnet V(TCNE)x (TCNE=tetracynoethylene) thin films is reported. MR increases linearly with applied magnetic field and shows a maximum at the ferrimagnetic ordering temperature. The suggested roles of oppositely spin polarized (pi)* electronic subbands and magnetization fluctuations due to the disordered nature of V(TCNE)x films are discussed

Remote sensing technique- a tool for environmental studies

Environment belongs to all and is important to all. As per definition of the Environment Protection Act, environment includes all the physical and biological surroundings and their interactions. The study of environment or rather environmental studies is a multi-disciplinary which needs knowledge interest from physical sciences (physics, chemistry, mathematics), biological sciences (botany, zoology, microbiology, biochemistry), social sciences, economics, sociology, education, geography) etc

Robustness Study of Fractional Order PID Controller Optimized by Particle Swarm Optimization in AVR System

In this paper a novel design method for determining fractional order PID (PIλDµ) controller parameters of an AVR system using particle swarm optimization algorithm is presented. This paper presents how to employ the particle swarm optimization to seek efficiently the optimal parameters of PIλDµ controller. The robustness study is made for this controller against parameter variation of AVR system. This work has been simulated in MATLAB environment with FOMCON (Fractional Order Modeling and Control) tool box.The proposed PSOPIλDµ controller has superior performance and robust compared to GA tuned PIλDµ controller. The results are also compared with PSO tuned PID controller

Analysis of Regenerative System in Steam Power Plant

The development of any country directly relates on capital energy consumption. The demand for power generation on the large scale is increasing day by day. Owing to their major contribution towards power production, thermal power plants have a vital role to play in the development of nation. Due to the scarcity of power, every power plant needs to be operated at maximum level of efficiency. In case of thermal power plants this applies equally to all its auxiliaries. The feed water heaters form a part of the regenerative system to increase the overall thermal efficiency of the plant. In the operation and maintenance of a power plant the feed water heaters are virtually neglected compared with other components. To realize the effect of feed water heating and an attempt is made in this project work to find the improvement in cycle efficiency due to FWH.nbs

A re-evaluation of finite-element models and stress-intensity factors for surface cracks emanating from stress concentrations

A re-evaluation of the 3-D finite-element models and methods used to analyze surface crack at stress concentrations is presented. Previous finite-element models used by Raju and Newman for surface and corner cracks at holes were shown to have ill-shaped elements at the intersection of the hole and crack boundaries. These ill-shaped elements tended to make the model too stiff and, hence, gave lower stress-intensity factors near the hole-crack intersection than models without these elements. Improved models, without these ill-shaped elements, were developed for a surface crack at a circular hole and at a semi-circular edge notch. Stress-intensity factors were calculated by both the nodal-force and virtual-crack-closure methods. Both methods and different models gave essentially the same results. Comparisons made between the previously developed stress-intensity factor equations and the results from the improved models agreed well except for configurations with large notch-radii-to-plate-thickness ratios. Stress-intensity factors for a semi-elliptical surface crack located at the center of a semi-circular edge notch in a plate subjected to remote tensile loadings were calculated using the improved models. The ratio of crack depth to crack length ranged form 0.4 to 2; the ratio of crack depth to plate thickness ranged from 0.2 to 0.8; and the ratio of notch radius to the plate thickness ranged from 1 to 3. The models had about 15,000 degrees-of-freedom. Stress-intensity factors were calculated by using the nodal-force method

Magnetic phase diagram of the antiferromagnetic pyrochlore Gd2Ti2O7

Gd2Ti2O7 is a highly frustrated antiferromagnet on a pyrochlore lattice, where apart from the Heisenberg exchange the spins also interact via dipole-dipole forces. We report on low-temperature specific heat measurements performed on single crystals of Gd2Ti2O7 for three different directions of an applied magnetic field. The measurements reveal the strongly anisotropic behaviour of Gd2Ti2O7 in a magnetic field despite the apparent absence of a significant single-ion anisotropy for Gd3+. The H-T phase diagrams are constructed for H//111], H//[110] and H//[112]. The results indicate that further theoretical work beyond a simple mean-field model is required.Comment: 4 figure

On the stranding of sea cow Dugong dugon at Mandapam along the Gulf of Mannar coast.

A dead male sea cow Dugong dugon (Muller) measuring 194 cm in total length and about 125kg in weight was stranded along the Gulf of Mannar coast at Mandapam.The morphometric measurements of specimen were taken and identified to species level