Infrared Background and Missiles Signature Survey

The proliferation of the missile threats in the existing threat scenario for airborne platform is a serious point of consideration for any mission planning. Missile warning system is an electronic warfare support system which gives warning to the pilot when a missile is detected in the scenario. The airborne platform has to be installed with missile warning sensors to give a spherical coverage, so that the sensors can detect the IR intensity variation in the ground scenario. This IR intensity variation has to be further analysed to differentiate the raising missile intensity from the varying background clutter. In order to differentiate the threat from the background clutter, the system should have sufficient background data set for online comparison thereby having less false alarm rate. The efficiency and performance of any missile warning system is validated with respect to its probability of declaration against the false alarm rate. Hence, to realize an efficient functioning of missile warning system, building IR background data base and missile signature database are the primary task. This paper details the methodology to be adapted for the building of tactical missile IR signatures and background data.Defence Science Journal, 2013, 63(6), pp.611-615, DOI:http://dx.doi.org/10.14429/dsj.63.576

Performance of different varieties/hybrids of black pepper (Piper nigrum L.) as mixed crop in coconut garden

A field experiment was conducted at Central Plantation Crops Research Institute, Kasaragod during 2001 to 2010 for studying the performance of black pepper varieties/hybrids when grown as mixed crop in 36 years old WCT coconut garden. Varieties such as Panniyur-1, Panniyur-2, Panniyur-3, Panniyur-4, Panniyur-5, Sreekara, Subhakara, Panchami, Kottanadan, OPKM, Collection 1041(Thevam) and hybrids such as HP-780, HP-105, HP-1411, HP-813 and HP-34 were grown in three replications. Among the varieties, Thevam, Panniyur- 4, Panniyur- 5, Sreekara, Subhakara and Panchami produced higher number of laterals with more spread (at five years age) compared to the other varieties. Thevam recorded significantly higher number of spikes (202.5), whereas the lowest was recorded in HP 780 (21.5). The spike length was the highest in Panniyur- 5 (15.4 cm), but was on par with varieties such as Panniyur-1, Panniyur-2, HP-1411 and OPKM. Sreekara recorded the lowest spike length of 8.7 cm. Six years mean dry spike yield indicated that, the yield was significantly higher with Thevam (1.81 kg/vine) followed by Panniyur- 5, which had recorded a yield of 1.12 kg/vine and differed significantly over other varieties. Panchami recorded higher oil (5.6 %) and oleoresin content (12.6%) and was on par with Panniyur-4, Kottanadan and OPKM. Due to the mixed cropping of black pepper in coconut garden an improvement in the coconut yield was noticed (132.2 nuts/palm/yr) during 2009-10 compared to the coconut monocrop (101.3 nuts/palm/yr) during 1999 to 2001

Modeling and Simulation of Triple Coupled Cantilever Sensor for Mass Sensing Applications

Cantilever sensors have been the growing attention in last decades and their use as a mass detector. This work presents design, modeling and analysis of Triple coupled cantilever(TCC) sensor using MEMS simulation software Comsol Multiphysics with critical  dimensions of 100μm length,20μm width and 2μm thickness. Simulations were performed based on finite element modeling techniques, where different resonant frequencies were observed for different modes of operation. It is also observed that the resonant frequency of the sensor decreases as some mass is applied on one particular cantilever. The various parameters greatly affecting the performance of TCC such as resonant frequency, dimensions, material and pressure or force applied on it.we also observed that while adding some mass on any one lateral cantilever, the resonant frequency of that respective mode reduced

Dynamics of FitzHugh-Nagumo excitable systems with delayed coupling

Small lattices of $N$ nearest neighbor coupled excitable FitzHugh-Nagumo systems, with time-delayed coupling are studied, and compared with systems of FitzHugh-Nagumo oscillators with the same delayed coupling. Bifurcations of equilibria in N=2 case are studied analytically, and it is then numerically confirmed that the same bifurcations are relevant for the dynamics in the case $N>2$. Bifurcations found include inverse and direct Hopf and fold limit cycle bifurcations. Typical dynamics for different small time-lags and coupling intensities could be excitable with a single globally stable equilibrium, asymptotic oscillatory with symmetric limit cycle, bi-stable with stable equilibrium and a symmetric limit cycle, and again coherent oscillatory but non-symmetric and phase-shifted. For an intermediate range of time-lags inverse sub-critical Hopf and fold limit cycle bifurcations lead to the phenomenon of oscillator death. The phenomenon does not occur in the case of FitzHugh-Nagumo oscillators with the same type of coupling.Comment: accepted by Phys.Rev.

Time Delay Effects on Coupled Limit Cycle Oscillators at Hopf Bifurcation

We present a detailed study of the effect of time delay on the collective dynamics of coupled limit cycle oscillators at Hopf bifurcation. For a simple model consisting of just two oscillators with a time delayed coupling, the bifurcation diagram obtained by numerical and analytical solutions shows significant changes in the stability boundaries of the amplitude death, phase locked and incoherent regions. A novel result is the occurrence of amplitude death even in the absence of a frequency mismatch between the two oscillators. Similar results are obtained for an array of N oscillators with a delayed mean field coupling and the regions of such amplitude death in the parameter space of the coupling strength and time delay are quantified. Some general analytic results for the N tending to infinity (thermodynamic) limit are also obtained and the implications of the time delay effects for physical applications are discussed.Comment: 20 aps formatted revtex pages (including 13 PS figures); Minor changes over the previous version; To be published in Physica

Antenatal Magnesium and Cerebral Palsy in Preterm Infants

To evaluate the relationship of maternal antenatal magnesium sulfate (MgSO4) with neonatal cranial ultrasound abnormalities and cerebral palsy (CP)