Achievements
SQUID MCG program
- A full-fledged 37 channel MCG system is being used as an advanced research tool for studying cardiac electrophysiological activities. These studies have been carried out over more than 150 patients referred by JIPMER, Pondicherry
- The MCG system has been successfully used to noninvasively measure His bundle signals as opposed to its conventional invasive recordings in hospital settings
- MCG has also been used to detect Coronary Artery Disease (CAD) on subjects under rest condition. Subsequently, this work has been extended with subjects under physical stress in order to explore the improvement on diagnostic information. Further, studies have been performed on observation of electrophysiological changes on subjects before and after treating CAD
- The MCG has also been demonstrated in an unshielded environment using signal processing techniques such as wavelet, independent component analysis, empirical mode decomposition etc.
- Novel signal processing schemes have also been developed to manage biological artefacts such as due to respiration, implanted devices and other artefacts affecting MCG.
SQUID TDEM program
- The electronic equipments required for the TDEM application were integrated with the Low Tc SQUIDs and tested in a site located near the laboratory. Subsequently, TDEM sounding measurements were carried out at a site near UCIL, Thumallapalle, AP.
- The decay transients recorded with SQUID shows the presence of a conducting layer buried at a depth of 600 m followed by an abnormal negative decay at later decay times. The negative decay is routinely attributed to induced polarization and other effects by various researchers working in the field for more than two decades. With careful interpretation of the recorded data and literature survey, it is speculated that the reason for the negative decay is due to the coupling of the self induced tertiary magnetic field produced by the transmitter loop in addition to the secondary magnetic field induced in the ground. The speculation on the existence of self induced tertiary magnetic field has been confirmed by conducting measurements in the same location with modified transmitter loop. The work has been communicated to a geophysical journal and it has attracted wide attention among the renowned geophysicists
- Similarly, the dual behaviour of fluxgate magnetometer in TDEM central loop measurements has been observed
Transient eddy current NDE program
- Transient eddy current NDE system based on fluxgate sensor for the detection of defects in conducting materials has been developed
- The transient eddy current NDE system has been used to correlate the defect depth with diffusion time of eddy currents for the defects in conducting materials
- A novel method for thickness measurement in conducting materials by apparent conductivity calculation through transient eddy current NDE has been established
- Single crystals of Cd0.9Zn0.1Te (CZT) have been grown in-house by travelling heater technique for gamma detector applications. With this sensor, the photo peaks of 133Ba and 241Am could be successfully resolved. The energy resolution at 31 keV and 81 keV of 133 Ba is found to be 8.4 % and 6.4 % respectively and the peak to valley ratio was 1.05. In the case of 241 Am source, it was 8.9 %, and the peak to valley ratio is ~ 1.8.
- Indigenously grown and fully characterized single crystals of Lead Zinc Niboate – Lead Titanate (PZN-PT) were deployed for development of surface acoustic wave (SAW) devices for examining the thermal expansion of reactor components immersed in liquid metal sodium. These piezoelectric crystals have a curie temperature of 190oC and hence can be used at temperatures below this. It is proposed to be used with waveguide for under sodium measurements now.
- LiNbO3 Oriented Wafers developed for High Temperature Transducer Applications
- Defect localization by orthogonally projected multiple signal classification approach for magnetic flux leakage fields
- Imaging buried defects in a three dimensional magnetically permeable bar using generalized inverse technique
- Localization of defects in magnetic permeable bar by Multiple signal classification approach using rotating dipole model
- Signal space separation for axial gradiometric magnetoencephalography measurements using block matrix inversion
- Utilization of SQUID based non-destructive evaluation system for detecting fatigue induced transformation of δ- ferrite to non-magnetic phases
- TDEM survey in the field at AMD camp, Cuddapah, AP
- Novel method of thickness measurement by the combination of transient eddy current NDE and apparent conductivity calculations.
- Development of novel algorithms for processing and analyzing biosignals
- Demonstration and validation of physiological signals of clinical relevance in collaboration with hospitals
- Deposition and characterization of superconducting NbN, MoN thin films with high upper critical field.
- Non-monotonic dependence of Bc2(0) and dBc2(T)/dT in Cr-Nb-Cr trilayer on superconductor thickness
- Analysis of superconducting fluctuations in MoN thin films and identification of 2D to 3D cross over under magnetic field.
- Interplay between current driven ferromagnetism in charge ordered antiferromagnetic Pr0.5Ca0.5MnO3 and superconducting YBa2Cu3O7−δ thin film multilayer
- Oscillation of TC in Pr0.5Ca0.5MnO3/YBa2Cu3O7-δ Multilayer
- Effect of current induced charge-order melting of Pr0.5Ca0.5MnO3 in partially masked superconducting Pr0.5Ca0.5MnO3/YBa2Cu3O7 bilayer
