NOPR Collection:

RF radiation from mobile phone towers and their effects on human body

2014-05-12T18:15:58Z

Title: RF radiation from mobile phone towers and their effects on human body Authors: Pachuau, Lalrinthara; Sailo, Lalrintluanga; Pachuau, Zaithanzauva; Lalngneia, P C Abstract: In the present paper, power density of RF radiation have been measured in close proximity (less than 50 m) to mobile base station Global System for Mobile Communications 900 (GSM 900) at the selected locality in Aizawl (23°44′53.5″N, 92°43′29.4″E), Mizoram, India. The mobile base station was erected in 2006. The study was carried out for the first time ever in the state in the year 2012 after six years of exposure to RF radiation with an aim to study different symptoms of health effects of RF radiation from mobile tower on nearby inhabitants. A survey was conducted on different health problems faced by the inhabitants living near the base station. Absolute power densities have been measured at some selected houses. Frequency spectrum was analysed at different sites. Different symptoms of RF exposure on human body are studied and the result is analysed. The measured power densities have been compared with standard limits given by various authorities, like International Commission on Non Ionizing Radiation Protection (ICNIRP), Bioinitiative 2012 and current National Standards. It has been observed that many inhabitants are having health complaints with different symptoms after the tower had been erected in 2006. Page(s): 186-189

Measurement of forward scattering coefficient of different water bodies at different frequencies

2014-05-14T18:15:14Z

Title: Measurement of forward scattering coefficient of different water bodies at different frequencies Authors: Calla, O P N; Bohra, Dinesh Abstract: The thrust of this study is to analyse the effect of scattering of electromagnetic waves on microwave links and tracking of low flying objects in the presence of strong ground bounce return from water bound areas. For this purpose, a ground based bi-static forward scatterometer has been used to generate co-polarized specular data at CJ, X, and Ku bands. The measurements are carried out on three types of water surfaces, i.e. tap water, natural lake water and saline water. All the three water surfaces are assumed to be slightly rough surfaces at the frequency of interest. Therefore, small perturbation model of slightly rough surface for forward scattering is a good selection to analyse data. The scattered microwave power from the terrain measured for 25° - 70° scattering angle (_s) with an interval of 5° in specular direction with transmitting antenna placed at an incidence angle (_i) of 45° from nadir illuminates the terrain keeping _i = _s = 0° at 5.825, 9.472 and 13.4 GHz in CJ, X and KU bands, respectively for vv and hh polarization with different antenna heights. The forward scattering coefficient computed with the help of experimental geometry parameters, which then compared with estimated value of scattering coefficient obtained from small perturbation model of slightly rough surface. A good agreement between observed and estimated scattering coefficient for horizontal (hh) and vertical (vv) polarization has been found in X and KU bands with a polarization reversal in CJ band. It is also observed that dissolved salt or impurities increase the value of scattering coefficient. The basic purpose of this study is to map and monitor the natural resources and to provide timely inputs for the planners to develop appropriate strategies for optimum utilisation of the resources. Page(s): 178-185

Diagnostic and statistical approach to the validation of Doppler radar rainfall around Chennai during 2006-2010

2015-02-12T11:57:03Z

Title: Diagnostic and statistical approach to the validation of Doppler radar rainfall around Chennai during 2006-2010 Authors: Amudha, B; Raj, Y E A; Thampi, S B; Ramanathan, RM A N Abstract: Rainfall data obtained from the precipitation accumulation product of the Doppler Weather Radar at Chennai has been compared and validated with the rainfall recorded at 16 stations located within 100 km range of the radar. Statistical parameters, like correlation, mean error and mean absolute error have been calculated. When rainfall is indicated by both radar and observatory, a high degree of correlation, at 0.98, between the conditional means of radar and observatory rainfall in various ranges is observed along with consistency in underestimation of rain by radar. A regression equation has been constructed to correct the rainfall estimates from radar. Physics and radar engineering aspects, which contribute towards limitations in rainfall estimation, have been discussed. Page(s): 163-177

Carbonaceous aerosols at an urban residential site in Agra

2014-05-13T18:17:26Z

Title: Carbonaceous aerosols at an urban residential site in Agra Authors: Meena, Rajneesh Kumar; Satsangi, Aparna; Lakhani, Anita; Kumari, K Maharaj Abstract: Carbonaceous aerosols are an important constituent of the aerosols and may be broadly divided in two parts, viz. organic carbon (OC) and elemental carbon (EC). Carbonaceous aerosol concentration was determined at an urban residential site in Agra. Sampling of fine particles (PM_2.5) was carried out during May to August 2011. The concentration of PM_2.5 at urban residential site was 55.3±17.4 μg m^-3, which is within the prescribed limits. OC varied from 7.6 to 37.5 µg m^-3,with an average of 18.2±6.4 µg m^-3;EC ranged 1.2 - 9.4 with an average of 3.2±1.6 µg m^-3; while total carbonaceous aerosols (TCA) varied from 13.6 to 69.4 µg m^-3. On an average, TCA accounted for 64.9% of PM_2.5 mass implying that carbonaceous aerosol is a significant component of PM_2.5. OC/EC ratio at the site was in the range of 3.5 - 11.9. OC/EC ratio indicates the contribution of both the primary and secondary sources. Page(s): 156-162