Through Wall Imaging Radar Antenna with a Focus on Opening New Research Avenues

This review paper is an effort to develop insight into the development in antennas for through wall imaging radar application. Review on literature on antennas for use in through wall imaging radar, fulfilling one or more requirements/specifications such as ultrawide bandwidth, stable and high gain, stable unidirectional radiation pattern, wide scanning angle, compactness ensuring portability and facilitating real-time efficient and simple imaging is presented. The review covers variants of Vivaldi, Bow tie, Horn, Spiral, Patch and Magneto-electric dipole antennas demonstrated as suitable antennas for the through wall imaging radar application. With an aim to open new research avenues for making better through wall imaging radar antenna, review on relevant compressive reflector antennas, surface integrated waveguide antennas, plasma antennas, metamaterial antennas and single frequency dynamically configurable meta-surface antennas are incorporated. The review paper brings out possibilities of designing an optimum through wall imaging radar antenna and prospects of future research on the antenna to improve radiation pattern and facilitate overall simple and efficient imaging by the through wall imaging radar

Impact of Field-Dependent Electronic Trapping Across Coulomb Repulsive Potentials on Low Frequency Charge Oscillations

We have performed Monte Carlo simulations to obtain the field dependence of electronic trapping across repulsive potentials in GaAs. Such repulsive centers are associated with deep level impurities having multiply charged states. Our results reveal a field‐dependent maxima in the electronic capture coefficient, and the overall shape is seen to depend on the background electron density due to the effects of screening. Based on the Monte Carlo calculations, we have examined the stability of compensated semiconductors containing such repulsive centers. Our analysis indicates a potential for low frequency charge oscillations which is in keeping with available experimental data

Long-term stability test of a triple GEM detector

The main aim of the study is to perform the long-term stability test of gain of the single mask triple GEM detector. A simple method is used for this long- term stability test using a radioactive X-ray source with high activity. The test is continued till accumulation of charge per unit area > 12.0 mC/mm2. The details of the chamber fabrication, the test set-up, the method of measurement and the test results are presented in this paper.Comment: 8 pages, 5 figure

Solving relativistic hydrodynamic equation in presence of magnetic field for phase transition in a neutron star

Hadronic to quark matter phase transition may occur inside neutron stars (NS) having central densities of the order of 3-10 times normal nuclear matter saturation density ($n_0$). The transition is expected to be a two-step process; transition from hadronic to 2-flavour matter and two-flavour to $\beta$ equilibrated charge neutral three-flavour matter. In this paper we concentrate on the first step process and solve the relativistic hydrodynamic equations for the conversion front in presence of high magnetic field. Lorentz force due to magnetic field is included in the energy momentum tensor by averaging over the polar angles. We find that for an initial dipole configuration of the magnetic field with a sufficiently high value at the surface, velocity of the front increases considerably.Comment: 16 pages, 4 figures, same as published version of JPG, J. Phys. G: Nucl. Part. Phys. 39 (2012) 09520

Time Series Study of Rhino Habitat and its Impact on Rhino Population in Gorumara National Park through Remote Sensing Technology

Gorumara National Park located within the flood plains of Jaldhaka and Murty river in the Dooars area of Northern West Bengal has a mosaic of natural vegetation consisting of tall grasslands, woodlands, tropical semi-evergreen forests and tropical moist deciduous forests, part of which get inundated in recurring floods. The Greater Indian One Horned Rhinoceros which is the flagship specie of this National Park has positively responded to the regular Wild Life Habitat Management regime introduced since 1995 showing trends of steady increase in its population as the habitat manipulation resulted in the increase of the Rhino habitat. This review tries to establish the Rhino population dynamics vis a vis increase in Rhino habitat using Remote sensing technology over the years since the area comes under purview of Protected Area network management

The conversion of Neutron star to Strange star : A two step process

The conversion of neutron matter to strange matter in a neutron star have been studied as a two step process. In the first step, the nuclear matter gets converted to two flavour quark matter. The conversion of two flavour to three flavour strange matter takes place in the second step. The first process is analysed with the help of equations of state and hydrodynamical equations, whereas, in the second process, non-leptonic weak interaction plays the main role. Velocities and the time of travel through the star of these two conversion fronts have been analysed and compared.Comment: 18 pages including 9 figure

The Chandrasekhar limit for quark stars

The Chandrasekhar limit for quark stars is evaluated from simple energy balance relations, as proposed by Landau for white dwarfs or neutron stars. It has been found that the limit for quark stars depends on, in addition to the fundamental constants, the Bag constant.Comment: LateX fil

Recertification guidelines for Massachusetts educators

The incorporation of the extracellular matrix (ECM) is essential for generating in vitro models that truly represent the microarchitecture found in human tissues. However, the cell-cell and cell-ECM interactions in vitro remains poorly understood in placental trophoblast biology. We investigated the effects of varying the surface properties (surface thickness and stiffness) of two ECMs, collagen I and Matrigel, on placental trophoblast cell morphology, viability, proliferation, and expression of markers involved in differentiation/syncytial fusion. Most notably, thicker Matrigel surfaces were found to induce the self-assembly of trophoblast cells into 3D spheroids that exhibited thickness-dependent changes in viability, proliferation, syncytial fusion, and gene expression profiles compared to two-dimensional cultures. Changes in F-actin organization, cell spread morphologies, and integrin and matrix metalloproteinase gene expression profiles, further reveal that the response to surface thickness may be mediated in part through cellular stiffness-sensing mechanisms. Our derivation of self-assembling trophoblast spheroid cultures through regulation of ECM surface alone contributes to a deeper understanding of cell-ECM interactions, and may be important for the advancement of in vitro platforms for research or diagnostics