Papers

Radon and thoron is a radioactive gas that emanates from rocks and soils and tends to concentrate in an indoor environment. Soil gas infiltration is identified as the most important source of residential radon. Other sources, including building materials and water extracted from wells, are also important in some circumstances. Radon is one of the major contributors to the ionizing radiation dose received by the general population. The dose due to radon and thoron are mainly delivered by their decay products which tend to get deposited in the respiratory organs of humans during breathing. In this study the measurement of radon, thoron and their daughter products concentration were carried out in the residential houses of Shahjahanpur, Uttar Pradesh, India using solid state nuclear track detector (SSNTD). The measurements were made in residential houses in the indoor environment of Shahjahanpur, using a twin chamber radon dosimeter. In the present study, it is found that the average value of radon and thoron concentration varies from 18.77 Bq/m3 to 44.95 Bq/m3 and 10.89 Bq/ m3 to 21.20 Bq/m3 respectively while the average value of radon progeny and thoron progeny concentration varies from 2.02mWL to 4.85 mWL and .29 mWL to 0.57 mWL respectively. The observed value of radon, thoron and their progeny concentration inside the dwellings were found to be lower than the ICRP value of 200 Bq/m3 and thus are within safe limits.

In this paper we propose Minimum Absolute Deviation (MAD) And Corrected Least Square (CLS) Methods of Estimation to Measure Technical Efficiency of Cobb-Douglas Frontier Production Function as a Linear Programming Problem, which can be extended with comfortable ease, to any Parametric Frontier Production Function.

The effects of radiation and hall current on MHD convective three dimensional flow in a vertical channel filled with a porous medium has been studied. We consider an incompressible viscous and electrically conducting incompressible viscous fluid in a parallel plate channel bounded by a loosely packed porous medium. The fluid is driven by a uniform pressure gradient parallel to the channel plates and the entire flow field is subjected to a uniform inclined magnetic field of strength Ho inclined at an angle of inclination  with the normal to the boundaries in the transverse xy-plane. The temperature of one of the plates varies periodically and the temperature difference of the plates is high enough to induce radiative heat transfer. The effects of various parameters on the velocity profiles, the skin friction, temperature field, rate of heat transfer in terms of their amplitude and phase angles are shown graphically.