No abstract

Cellar workplaces are considered as confined environment with challenging indoor air quality having higher than normal pollutants particularly that of soil gas origin. Radon, a major soil gas, infiltrates and accumulates within indoor spaces and becomes harmful in the absence of ventilation. Radon level in bank basements (cellars) in Ilorin, Lagos and Akure have been sampled and analysed in this study. In Nigeria, most workers in basements are unaware of radon, and there is limited documented research on its health hazards. The survey parameters of radon concentrations were floor types, geographical locations and the influence of atmospheric conditions. Corentium monitor, a continuous, digital radon monitor, temperature meters and Prologue wireless weather station were used for the experiments. Annual average indoor radon concentration for the survey period was 23 Bq/m 3 . The calculated mean annual effective doses in basements and different floors were below the recommended ICTR level of 3 mSv/y.

The application of fluid and heat transfer in electronic and nuclear technology is gaining popularity, particularly in equipment's life span and risk management. However, further study is required for applications involving rectangular cylinders placed inside a square cavity. This study investigates the effects of height ratio (𝐻𝑅), and width ratio (𝑊𝑅) for Prandtl number 𝑃𝑟=0.71 on natural convective heat transfer and the flow field around the annulus of a square domain fitted internally with a heated rectangular cylinder. The square enclosure and the inner rectangular cylinder walls were respectively maintained at cold and hot isothermal conditions. COMSOL Multiphysics (Version 5.6) software was adopted to implement the governing equations and boundary conditions. The results are presented in the form of streamlines, isothermal contours, and Nusselt number (Nu). The study reveals that the combined average Nu of the rectangular cylinder walls improves with 𝐻𝑅, 𝑊𝑅, and Rayleigh number (Ra). The maximum Nu occurred at 𝐻𝑅=0.7, and 𝑊𝑅=0.7; however, height variation at peak average Nu was 37.7% greater than width variation at peak average Nu. This study finds applications in the cooling of electronic chips and aerospace engines.

Basement workplaces are considered as confined environment with challenging indoor air quality having higher than normal pollutants particularly that of soil gas origin. Radon a major soil gas infiltrates and accumulates within indoor spaces and becomes harmful in the absence of natural or mechanical ventilation. Radon level in bank basements in Ilorin, Lagos and Akure have been sampled and analysed in this study. The paper presents the investigations conducted to measure the radon concentration in the occupied basement component of the bank buildings. Most workers in basements are unaware of radon, and there is limited documented research on its health hazards in Nigeria. The survey parameters were radon concentrations, floor levels, geographical locations and the influence of atmospheric conditions. Corentium monitor, a continuous, digital radon monitor, in addition to, temperature meters and Prologue wireless weather station were used for the experiment. The result showed an indoor radon concentration and effective doses annual mean values of 23 Bq/m3 and 0.0896mSy/y respectively in the occupied basements.