Investigation of bio polymer electrolyte based on cellulose acetate-ammonium nitrate for potential use in electrochemical devices.

Proton conducting materials create prime interest in electro chemical device development. Present work has been carried out to design environment friendly new biopolymer electrolytes (BPEs) using cellulose acetate (CA) complex with different concentrations of ammonium nitrate (NH4NO3), which have been prepared as film and characterized. The 50mol% CA and 50mol% NH4NO3 complex has highest ionic conductivity (1.02×10-3Scm-1). Differential scanning calorimetry shows the changes in glass transition temperature depends on salt concentration. Structural analysis indicates that the highest ionic conductivity complex exhibits more amorphous nature. Vibrational analysis confirms the complex formation, which has been validated theoretically by Gaussian 09 software. Conducting element in the BPEs has been predicted. Primary proton battery and proton exchange membrane fuel cell have been developed for highest ionic conductivity complex. Output voltage and power performance has been compared for single fuel cell application, which manifests the present BPE holds promise application in electrochemical devices.

Background radiation and individual dosimetry in the costal area of Tamil Nadu, India.

South coast of India is known as the high-level background radiation area (HBRA) mainly due to beach sands that contain natural radionuclides as components of the mineral monazite. The rich deposit of monazite is unevenly distributed along the coastal belt of Tamil Nadu and Kerala. An HBRA site that laid in 2×7 m along the sea was found in the beach of Chinnavillai, Tamil Nadu, where the maximum ambient dose equivalent reached as high as 162.7 mSv y(-1). From the sands collected at the HBRA spot, the high-purity germanium semi-conductor detector identified six nuclides of thorium series, four nuclides of uranium series and two nuclides belonging to actinium series. The highest radioactivity observed was 43.7 Bq g(-1) of Th-228. The individual dose of five inhabitants in Chinnavillai, as measured by the radiophotoluminescence glass dosimetry system, demonstrated the average dose of 7.17 mSv y(-1) ranging from 2.79 to 14.17 mSv y(-1).

Evaluation of genetic alterations in inhabitants of a naturally high level background radiation and Kudankulam nuclear power project site in India.

Evaluation of genetic alterations in inhabitants of an area of Tamil Nadu, India, chronically exposed to high background radiation (HBRA), was the major purpose of the present study. A total of 216 samples (exposed inhabitants, 108; control subjects, 108) were selected based on the confirmation of radiation dose level using thermoluminescence dosimetry (TLD). After signing a consent form, volunteers provided blood samples (5 ml each) to establish cell cultures at 52 h. One hundred complete metaphase cells from each subject were evaluated for karyotyping. The frequencies of chromosomal alterations (CA) were found to be higher in the exposed groups and the aberrations predominately observed were of chromatid-type. Smoking was found to have considerable effect on the frequency of CA in exposed subjects. With the comet assay for DNA damage, a significant increase in comet tail frequency was also observed in exposed subjects compared to controls. At present there are no radioepidemiological data regarding the cytogenetic studies in these areas. Furthermore, the Kudankulam nuclear power plant nuclear power plant is being constructed in the same area. The study gives potentially important information on the general health effects due to radiation exposure and increases people's understanding of the hazardous nature of chronic low level natural radiation exposure. However, we may conclude that the HBRA by itself does not pose any significant risk of genetic damage as measured by conventional cytogenetic analysis.

Laser Raman and ac impedance spectroscopic studies of PVA: NH4NO3 polymer electrolyte.

Ion conducting polymer electrolyte PVA:NH(4)NO(3) has been prepared by solution casting technique and characterized using XRD, Raman and ac impedance spectroscopic analyses. The amorphous nature of the polymer films has been confirmed by XRD and Raman spectroscopy. An insight into the deconvoluted Raman peaks of upsilon(1) vibration of NO(3)(-) anion for the polymer electrolyte reveals the dominancy of ion aggregates at higher NH(4)NO(3) concentration. From the ac impedance studies, the highest ion conductivity at 303 K has been found to be 7.5x10(-3)Scm(-1) for 80PVA:20NH(4)NO(3). The conductivity of the polymer electrolytes has been found to depend on the degree of dissociation of the salt in the host polymer matrix. The combination of the above-mentioned analyses has proven worth while and in fact necessary in order to achieve better understanding of these complex systems.

Population dose from indoor gamma exposure in the dwellings around Kudankulam nuclear power plant.

To assess the population dose due to the natural background radiation around the upcoming Kudankulam nuclear power plant, a systematic investigation has been carried out by measuring the indoor gamma dose. In total, 159 dwellings have been selected around the Kudankulam nuclear power plant area i.e. in Radhapuram and Nanguneri taluk (sub-districts) for the measurement. The geometric mean value of indoor gamma dose rate is 305 +/- 48 nGy h(-1) and 273 +/- 50 nGy h(-1) in Radhapuram and Nanguneri taluks (sub-districts), respectively. The annual effective dose due to indoor gamma radiation to the population has been found to be 1.5 mSv and 1.36 mSv in Radhapuram and Nanguneri taluks, respectively.

Gamma dose measurement in dwellings of Agastheeswaram Taluk of Kanyakumari district, lying 30 km radius from Kudankulam nuclear power plant site.

Most of the building materials contain naturally occurring radioactive elements, the most important of which are potassium (40)K and the members of two natural radioactive series, which can be represented by the isotopes of thorium (232)Th and Uranium (238)U. The presence of these radioisotopes in the materials causes external exposure to the people who live in the building. In addition, the disintegration of Uranium (238)U increases the concentration of radon gas (222)Rn and of its daughters in the house. So a systematic indoor gamma dose measurement has been performed in the dwellings of Agastheeswaram Taluk of Kanyakumari district, which is lying within the 30 km radius from the upcoming Kudankulam nuclear power plant site. The geometric mean of annual absorbed dose from gamma radiation in dwellings has been found to be 278 nGyh(-1). The seasonal variation of indoor gamma dose measurements has also been studied. Significant differences have been observed in dwellings built of different materials such as concrete, tiled, etc.

Studies on the distribution of 210Po and 210Pb in the ecosystem of Point Calimere Coast (Palk Strait), India.

A systematic study on the natural radionuclides such as 210Po and 210Pb in the environmental matrices of Point Calimere ecosystem has been undertaken to establish a baseline data on the radiation profile of Point Calimere environment. The environmental samples such as water, sediment and biota (seaweeds, crustaceans, molluscs and fish) have been subjected to analyses. It has been observed that the concentration of 210Po and 210Pb in the water samples of Point Calimere to be 0.5 mBq/l and 1.3 mBq/l, respectively. The soft tissues of the organisms accumulated higher 210Po content while shells and bones contained more 210Pb. The bivalve molluscs Meretrix casta have been identified to accumulate higher concentration of 210Po suggesting that they could serve as bio-indicator of radionuclides like 210Po in the Point Calimere ecosystem. The concentration factor of 210Po for the biotic components ranged from approximately 10(3) to 10(6) while for 210Pb it ranged from approximately 10(3) to 10(5).

Laser Raman and FTIR studies on Li+ interaction in PVAc-LiClO4 polymer electrolytes.

The polymer electrolytes composed of poly(vinyl acetate) (PVAc) with various stoichiometric ratios of lithium perchlorate (LiClO(4)) salt have been prepared by solution casting method. The techniques Fourier transform infra-red (FTIR) and Laser Raman spectroscopy have been used to monitor polymer-salt complex formation, ion-ion and ion-polymer interactions as a function of salt concentration. Significant changes in both Laser Raman and FTIR spectra are observed which reveals an interaction between ester oxygens with lithium cation coordination. These results strongly suggest the interaction of lithium cation and network polymer chains. When the salt content is increased, the intensity of the internal Raman modes of the ClO(4)(-) increases. The ClO(4)(-) stretching mode observed at 934 cm(-1) in Laser Raman shows some additional shoulder peaks with increase in salt concentration. This reveals the presence of free anions, ion contact pairs and higher order ionic clusters. From the FTIR and Laser Raman results the transport mechanism of ions in PVAc:LiClO(4) polymer electrolytes has been discussed.

Study of radionuclide distribution around Kudankulam nuclear power plant site (Agastheeswaram taluk of Kanyakumari district, India).

The activity concentration of primordial radionuclides 238U, 232Th and 40K have been measured in the sand samples of Agastheeswaram taluk of Kanyakumari district using gamma-ray spectrometer. The average activity of 232Th, 238U and 40K are found to be 5787.1, 1082.9 Bq kg(-1) and BDL, respectively. The total average absorbed dose rate owing to the presence of 232Th, 238U and 40K is found to be 3900.4 nGy h(-1). The annual effective dose is 4.7 mSv y(-1) and the results are discussed in this paper.

Indoor gamma dose measurements in Gudalore (India) using TLD.

Indoor gamma radiation dose rates were measured inside residential buildings in Gudalore using a CaSO4:Dy thermoluminescent dosimeter for 1 year. Significant seasonal variations are observed. The highest dose rate is observed during summer and the lowest in winter. The dose rates observed are between 77.9 and 229.3 nGy h(-1) and may be attributed to the type of building materials used in the dwellings monitored. The calculated mean annual effective dose equivalent rates range between 477.6 microSv y(-1), for the inhabitants of mud houses to 1406.3 microSv y(-1), for those living in terrace houses made of cement and brick.

Natural radionuclide distribution in soils of Gudalore, India.

The concentration of primordial radionuclides in soil samples of Gudalore Taluk in the Udagamandalam district has been measured from the gamma ray spectrum of the soil. The mean activities of 232Th, 238U and 40K are 75.3 +/- 44.1, 37.7 +/- 10.1 and 195.2 +/- 85.1 Bq kg-1 dry weight, respectively. The average outdoor absorbed dose rate in air at a height of 1 m above ground is 74.3 +/- 27.8 nGy h-1, corresponding to an annual effective dose equivalent of 455.6 microSv. The dose equivalent ranges from 168.3 to 1250.5 microSv. The results have been compared with other global radioactivity measurements and evaluations.