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Irradiation is considered as an efficient method for the reduction of microorganisms in food. It has been used to improve the safety and shelf life of food products. The present investigation is aimed at studying the influence of gamma irradiation (3 and 5 kGy) and subsequent storage at refrigeration temperature (4oC) on the chemical, microbial qualities and extended shelf life of squid (Doryteuthis sibogae). The total volatile base nitrogen (TVB-N) and trimethyl amine nitrogen values (TMA-N) of the irradiated squid samples significantly decreased in comparison with the control (non-irradiated) stored at 4oC. The thiobarbituric acid values for the irradiated squid was significantly lower than of the non-irradiated samples stored at 4oC (p

The structural dependence of nonlinear optical properties associated with ADP-doped PVA/PVP polymer composites is discussed in this work. Polymer composites are fabricated using the solution casting method. X-ray diffraction (XRD) was used to perform structural analysis on these samples whose average crystallite size increases with an increase in dopant concentration. Results from UV–Vis–NIR spectra show that the samples are transparent in the IR region. The Z-scan technique was established by following the method described by Sheik-Bahae et al. The shape of the open aperture plot suggests that the samples exhibit two-photon absorption. The NLO properties such as nonlinear absorption coefficient (β) , two-photon absorption cross-section ( σ 2) and the imaginary part of third-order nonlinear susceptibility (χ (3)) were investigated at 1064 nm and these values were found to be in the order of ∼ 1 0 − 7 W/cm, ∼ 1 0 − 2 0 cm4/GW and ∼ 1 0 − 1 4 esu, respectively. The open aperture Z-scan method yielded optical limiting data, from which the optical limiting threshold was calculated to be in the order of ∼ 1 0 1 3 W/m2. Functional data analysis uses a suitable basis representation to assess the functional correlation between global and local variables. [ABSTRACT FROM AUTHOR]

The presence of naturally occurring radionuclides is common in all living and non-living frameworks, which are part of our environment. The activity concentration of 40K radionuclide was estimated using gamma spectrometry in some medicinal plants and transfer factors (TF), and Average Annual Committed Effective Dose (AACED) was evaluated. The standard methods were followed in the process of sample collection and processing. The mean activity concentrations of 40K were 223 and 1330 Bq kg−1 in soil and medicinal plants, respectively. The mean TF and AACED were found to be 6.5 and 8.2 μ Sv y−1, respectively. Higher activity concentration was observed in some medicinal plants due to the selective and preferential uptake of this radionuclide depending on their medicinal utility. The study may help to form the database and safety regulations connected with 40K activity in medicinal plants. [ABSTRACT FROM AUTHOR]

A series of polyaniline (Pani)-filled chain extended polyurethanes (PUs) were prepared by condensation polymerization of castor oil with methylene diisocyanate (MDI) as crosslinker and diamino diphenyl sulfone (DDS) as chain extender. The effect of different amounts of Pani (varying from 5% to 25%) on the chain extended PUs has been reported. The Pani-filled chain extended PU sheets were characterized by their physico-mechanical properties such as density, tensile strength, percentage elongation at break and surface hardness. Electrical properties, such as volume and surface conductivity, also have been reported. These results are corroborated with microcrystalline parameters of PU/Pani estimated using wide angle X-ray scattering (WAXS). Polym. Eng. Sci. 44:772-778, 2004., INTRODUCTION The physical and chemical properties of polymer mixtures are of commercial and academic interest, since they provide a convenient route for modifying polymer properties to meet specific needs. Among [...]

This research work presents the preparation of ethylene-propylene-diene-monomer (EPDM) composites filled with different concentrations of lead oxide (PbO) and magnetite (Fe3O4). The catalytic role of Fe3O4 on peroxide vulcanisation was studied. The morphological studies were done by the FESEM analysis. The evaluation of gamma shielding ability of synthesised composites was done for 59.54 keV gamma rays using a gamma spectrometer. Various shielding parameters, such as percentage attenuation (%Att), linear attenuation coefficient (μ), relaxation length (λ), half value (HVL) and tenth value layer (TVL) thickness, were evaluated for synthesised composites. The obtained results showed that, the shielding ability of the synthesised composites increases with an increase in PbO concentration. Also, the thermal stability of the synthesised composites was studied by TGA and it was found that thermal stability of the synthesised composites decreases with an increase in PbO concentration. Thus by comparing the results of radiation shielding ability and thermal stability, EPDM, with 40 phr PbO and 20 phr Fe3O4, can be considered as an ideal shielding material among the synthesised composites. [ABSTRACT FROM AUTHOR]

Silver/Polyvinyl alcohol/Polyvinylpyrrolidone (Ag/PVA/PVP) nanocomposite films were synthesized using solution casting technique and the samples were exposed to gamma radiation for different doses 0, 25, 50 and 75 kGy. The samples were characterized through Ultra Violet-Visible spectroscopy (UV-Vis), Fourier Transformation Infrared Spectroscopy (FTIR), Field Emission Scanning Electron Microscope (FESEM), Energy-dispersive X-ray spectroscopy (EDAX) and Transmission electron microscopy (TEM). The absorption spectrum shows the surface plasmon resonance (SPR) peak at 424 nm, confirming the formation of silver nanoparticles in PVA/PVP matrix. Antibacterial activity of Ag/PVA/PVP nanocomposite films was investigated against Gram-positive bacteria (Bacillus subtilis, Staphylococcus aureus) and Gram-negative bacteria (Escherichia coli, Klebsiella pneumonia) using agar diffusion method. The samples showed inhibition activity against both Gram-positive and Gram-negative bacteria. the study reveals, the irradiated Ag/PVA/PVP nanocomposite films shows good antibacterial activity against the Gram-positive and Gram-negative bacteria. [ABSTRACT FROM AUTHOR]

A walk-in type 222Rn calibration chamber of volume 22.7 m3, which has traceability to international standards, is established at the Centre for Advanced Research in Environmental Radioactivity, Mangalore University, India. It has a human–machine interface communication system, a programmable logic controller and sensor feedback circuit for controlling and data acquisition of relative humidity (RH) and temperature (T). An innovative method for the generation of desired 222Rn concentration (a few hundred Bq m−3 up to about 36 kBq m−3) using soil gas as a source was adopted. Leak rates of 222Rn from the chamber for the mixing fan ON and OFF conditions were determined to be 0.0011 and 0.00018 h−1 respectively. With the exhaust system fully turned on, the maximum clearance rate of the chamber was 0.58 ± 0.07 h−1. Excellent spatial uniformity in 222Rn concentration in the chamber was confirmed (with a mean value of relative standard deviation < 12%) through measurements at 23 locations using CR-39 film-based passive devices. Demonstration of calibration applications was performed using charcoal canister and PicoRad vials as the 222Rn adsorption devices. The study shows that gamma spectrometry is a convenient alternative approach to liquid scintillation analysis of PicoRad vials for 222Rn measurement. [ABSTRACT FROM AUTHOR]