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Coal based thermal power plants contribute about ~ 72% of the power generation in India. Indian coal is of bituminous type, having a high ash content with 55–60% ash. Due to considerable environmental importance the collected fly ash has become a subject of worldwide interest in recent years. In the present study radon exhalation rate and the activity concentration of 226Ra, 232Th and 40K radionuclides in fly ash samples from Kasimpur Thermal Power Plant, Aligarh, Uttar Pradesh, India have been measured by 'Sealed Can technique' using LR-115 type II detectors and a low-level NaI (Tl)- based gamma-ray spectrometer, respectively. Radon exhalation rate has been found to vary from 57.1 ± 5.3 to 119.4 ± 7.7 mBq m−2 h−1 with an average value of 87.3 ± 5.8 mBq m−2 h−1. Activity concentration of 226Ra ranged from 20.0 ± 8.5 to 30.0 ± 9.7 Bq kg−1 with an average value 23.4 ± 9.0 Bq kg−1, 232Th ranged from 17.0 ± 9.9 to 69.0 ± 13.8 Bq kg−1 with an average value of 46.5 ± 12.1 Bq kg−1 and 40K ranged from 130.0 ± 7.2 to 332.0 ± 11.1 Bq kg−1 with an average value of 177.0 ± 8.1 Bq kg−1. [ABSTRACT FROM AUTHOR]

Single phase Bi0.9-xLa0.1NdxFeO3 (BLNFOx) (x=0.05, 0.07, and 0.1) multiferroic ceramics were prepared to study the effect of combine substitution of La and Nd in BiFeO3 (BFO). X-ray diffraction studies revealed phase transition from rhombohedral (R3c) to triclinic (P1) on substitution of 05 and 07 mol % of Nd and subsequent transition to monoclinic C2/c with 10 mol % of Nd along with 10 mol % of La. These structural phase transitions and weakening of long range ferroelectric order with increasing x are also confirmed from Raman spectra. The existence of ferroelectricity and the corresponding Curie temperature for all noncentrosymmetric composition were determined using differential thermal analysis. Small remnant magnetization of 0.067 emu/g is observed in (BLNFO)x=0.07 as a result of collapse of space modulated spin structure. For pure BFO dielectric anomaly was observed at 355 °C corresponding to Neel temperature. Due to coexistence of long range ferroelectric order and canted antiferromagnetic orders in (BLNFO)x=0.05 and 0.07 the magnetoelectric effects were observed below Neel temperature at 302 and 294 °C, respectively, near which magnetoelectric coupling is obvious. [ABSTRACT FROM AUTHOR]

Single phase Bi0.9-xLa0.1NdxFeO3 (BLNFOx) (x=0.05, 0.07, and 0.1) multiferroic ceramics were prepared to study the effect of combine substitution of La and Nd in BiFeO3 (BFO). X-ray diffraction studies revealed phase transition from rhombohedral (R3c) to triclinic (P1) on substitution of 05 and 07 mol % of Nd and subsequent transition to monoclinic C2/c with 10 mol % of Nd along with 10 mol % of La. These structural phase transitions and weakening of long range ferroelectric order with increasing x are also confirmed from Raman spectra. The existence of ferroelectricity and the corresponding Curie temperature for all noncentrosymmetric composition were determined using differential thermal analysis. Small remnant magnetization of 0.067 emu/g is observed in (BLNFO)x=0.07 as a result of collapse of space modulated spin structure. For pure BFO dielectric anomaly was observed at 355 °C corresponding to Neel temperature. Due to coexistence of long range ferroelectric order and canted antiferromagnetic orders in (BLNFO)x=0.05 and 0.07 the magnetoelectric effects were observed below Neel temperature at 302 and 294 °C, respectively, near which magnetoelectric coupling is obvious. [ABSTRACT FROM AUTHOR]

The synthesis and the structure, dielectric and magnetic properties of the single-phase BiFe[O.sub.3] multiferroic ceramics are discussed. The impact of coalesce doping and the presence of ferroelectricity in the system are also determined.

Abstract: Bismuth ferrite (BFO) and La-substituted BFO with composition Bi1−x La x FeO3 (x=0.05, 0.1 and 0.15) (BLFO x=0.05–0.15) ceramics were prepared using the solid state reaction route. A structural phase transition from rhombohedral phase to triclinic phase was observed for BLFO x=0.05–0.15 ceramics. Modulus spectroscopy reveals the deviation of dielectric behavior from ideal Debye characteristics and the dependence of conductivity on ion hopping in BFO and BLFO x=0.05–0.15 ceramics. The conductivity of the BFO ceramics decreases for La content of 5mol%, followed by a subsequent increase with 10 and 15mol% of lanthanum doping. The typical values of the activation energies at high temperature reveal the contribution of short range movement of doubly ionized oxygen vacancies to the conduction process in BFO and BLFO x=0.05 ceramics. Both short range and long range motion of oxygen vacancies are responsible for large conductivity in BLFO x=0.1 and 0.15 ceramics. [Copyright &y& Elsevier]

This study summarizes the seasonal experimental data on the activity concentrations of indoor 222Rn (Radon), 220Rn (Thoron) and their progeny in Mansa and Muktsar districts of Punjab (India) using LR-115 solid state nuclear track detector based time integrated pin-hole cup dosimeters and deposition based progeny sensors for the assessment of radiological dose. The indoor 222Rn concentration was observed higher in the rainy and winter seasons while 220Rn concentration was observed higher in the winter season. However, Equilibrium Equivalent Concentrations (EECs) of 222Rn and 220Rn exhibited distinct seasonal behaviour unlike their parent nuclides. The average equilibrium factors for 222Rn (FRn) and 220Rn (FTn) were found 0.47 ± 0.1 and 0.05 ± 0.01, respectively. The annual arithmetic means of unattached fractions of 222Rn (fpRn) and 220Rn (fpTn) were found to be 0.09 ± 0.02 and 0.10 ± 0.02, respectively. The attachment rate (XRn) and attachment rate coefficients (β) of 222Rn progeny were also calculated to understand the proper behaviour of progeny species in the region. A new alpha flux based technique has been proposed and used for the assessment of absorbed dose rate and annual effective dose rate for radiation protection purpose. [ABSTRACT FROM AUTHOR]