Physics
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Item Mechanical properties and radiological implications of replacing sand with waste ceramic aggregate in ordinary concrete.(ELSEVIER, 2024) OLARINOYE, OYELEKE; Kolo, M. T.,; Amuda, D. B., Oche, C. O., Mohammed, B., Alzahrani, J. S., & Al-Buriahi, M. S.The mining of aggregates for the production of concrete creates ecological problems. In this study, the effect of partially replacing sand as fine aggregate (FA) with waste ceramic tiles (WCT) on the density, compressive strength (CS), specific radioactivity of naturally occurring radioactive materials (238U, 232Th, and 40K), and the radiation shielding competence of concrete was investigated. Ordinary concrete samples consisting of cement, fine aggregate (river sand), coarse aggregate (granite), and water were prepared in 50 mm ×50 mm x 50 mm cubical steel moulds. The samples were coded as C-WCT0, C-WCT5, C-WCT10, C-WCT15, C-WCT20, and C- WCT25, representing concrete samples in which the FA component was replaced by 0, 5, 10, 15, 20, and 25% pulverized WCT, respectively. The CS and density of the samples were determined after 7-, 14-, and 28-day curing periods. The gamma spectrometric method was used to determine the specific activity of 238U, 232Th, and 40K using a hyper pure germanium detector. The photon and neutron shielding parameters of the concrete blocks were calculated with the aid of the EPICS2017 cross-section library and relevant standard formulae. The mean CS for each concrete category increase with curing age. The density of the concrete varied from 2213 kg/ m3 to 2488 kg/m3 as the FA replacement level rose to 15%. Using WCT as a partial replacement for FA altered the chemical composition and decreased the specific activities of 238U, 232Th, and 40K, in the concrete samples. C- WCT15 had the best gamma photon and fast neutron absorption features among the concrete samples. The use of WCT as aggregate in concrete production is a sustainable and environmental-friendly way of producing concrete for general civil engineering and shielding applications in medical and other radiation facilities. This study also affirms that using alternative materials with lower specific activity to replace sand is radiologically desirable in reducing the indoor radiation dose of occupants of concrete-based structures. The replacement of 15% sand by WCT produced stronger, radiologically safer, and more effective radiation absorbing concrete.Item Assessment of Environmental Background Gamma Radiation Variation in Minna Area of Nigeria(Taylor and Francis, 2024) Adeiza Stephen, A.,; OLARINOYE, OYELEKE; Kolo, M. T.,; Kasim, I.Radiation has been acknowledged to be responsible for deleterious conditions in living tissues. Hence, environmental background gamma radiation (BGR) measurement is crucial from an environmental and health perspective. In this study, due to the absence of comprehensive background gamma radiation data and the increasing numbers of anthropogenic activities that could increase the BGR level, such as where mining activities are active. The BGR in the Minna area of Niger State, Nigeria, was measured and analyzed in this study. In-situ measurement of the background gamma radiation level was carried out using a well-calibrated portable handheld GQ GMC-500 Plus nuclear radiation detector at an elevation of about 1.0m above ground level. global positioning system from Garmin (GPSmap 78s) was adopted for identifying geographical locations. A total of 1172 points were surveyed across the study area for background environmental radiation. The BGR values ranged from 0.102 to 0.147 lSv/h, with an overall mean value of 0.126 lSv/h. The average measured dose rate was more than twice the reported world average value of 0.059 lSv/h. The annual effective dose equivalent (AEDE) for the research area was calculated to be 0.221 mSv/y on average. The mean AEDE is lower than the ICRP recommended limit. This shows that the population of the Minna area is radiologically safe based on the estimated AEDE value. Similarly, the excess lifetime cancer risk (ELCR) value ranged from 0.626�10 0.774±0.09�10 −3 −3 to 0.901�10 −3 mSv/y with a mean value of mSv/y. The mean value of AEDE is below the 0.24 mSv/y permissible limits as recommended by the International Commission on Radiological Protection (ICRP). The mean ELCR value exceeds the average world value of 0.29�10 −3 . Also, the mean organ dose values estimated for the whole body, liver, kidney, testes, bone marrow, ovaries, and lungs are 0.150±0.02, 0.102±0.01, 0.137±0.02, 0.181±0.02, 0.152±0.02, 0.128±0.02 and 0.141±0.02 mSv/y respectively. The differences in the calculated mean of BGR were attributed to natural and human factors. Geological variation is a fundamental factor that influences the changes in BGR. Human activities, mining, building materials, and the use of phosphate fertilizers in agricultural practices are responsible for the differences in BGR. The ELCR implies that terrestrial gamma radiation does not pose any immediate radiological health effects on residents of the area, but there is a tendency for long-term health hazards in the future, such as cancer, due to the dose accumulatedItem Estimation of indoor gamma radiation dose rate from concrete blocks constructed from tin mine tailings.(ELSEVIER, 2023) OLARINOYE, OYELEKE; Kolo, M. T.,; Shittu, H. O., & Anumah, A. S.The use of building materials made from geological sources contributes greatly to the indoor radiation exposure of human. As a result, it is critical for public health that building materials be screened for elevated radionuclide concentrations. This research measures the primordial radionuclide content of concrete blocks derived from mine tailings and also estimates the indoor annual effective dose rate (AEDR) and associated parameters. Furthermore, it presents a simple empirical relationship for evaluating dose rate per unit specific activity due to radionuclides from a wall of arbitrary dimensions. Twelve concrete blocks constructed using tin mine tailings as fine aggregates were collected locally and analyzed for 235U, spectrometry analysis. The concentration of 238 232Th and 40K content using gamma U ranged from 86.29 to 197.73 Bq/kg with a mean of 120.93 Bq/kg. Also, the specific activity of 232Th and 40 K is within the limits: 99.01–353.67 Bq/ kg and 500.71–1021.77 Bq/kg with mean values of 248.31 Bq/kg and 635.10 Bq/kg, respectively. Obtained dose rate per unit specific activity agreed well with data from literature. Using the derived values of dose rate per unit specific activity, the annual effective dose rate (AEDR) obtained from a typical Nigerian room varies significantly from that obtained from equations in referenced documents where a different room configuration was used. The mean AEDR from the realistic Nigerian room (3.6 × 3.6 × 3 m3 ) was higher than the world average value but less than the recommended safety limit of 1 mSvy 1 . Some of the blocks with AEDR more than the safety limits were recommended for use in superficial quantities for building construction. The model derived in this study can be applied to calculate dose rates within any room configuration.Item ASSESSMENT OF NATURAL RADIOACTIVITY LEVELS AND RADIATION HAZARDS IN THE TERTIARY INSTITUTIONS IN MINNA, NIGER STATE, NIGERIA.(2012-01-15) Kolo, M. T.,; Baba-Kutigi, A. N.,; OLARINOYE, OYELEKE; Sharifat, I.Activity concentrations of natural radionuclides in 30 surface soil samples collected across the three campuses of the two tertiary institutions in Minna, Niger State, Nigeria, were studied and evaluated. This survey was carried out using gamma spectrometric technique which employs NaI(Tl) gamma detector at the Center for Energy Research and Training (CERT), Ahmadu Bello University, Zaria, Nigeria. The mean values for the activity of 226Ra, 232Th and 40K were found to be 7.8±1.3Bqkg-1, 29.4±0.9Bqkg-1 and 229.4±1.8Bqkg-1 respectively. The activity profile of the primordial radionuclides in the soil samples investigated showed the existence of low level activity across the three campuses. The mean value of the annual effective dose equivalent obtained from this study is 0.04mSvyr-1, with mean external hazard index of 0.2. These average values fall within the internationally provided safety range for outdoor radiation exposure. The values obtained from this investigation for all the radiation parameters for the studied soil samples showed that none of the campuses investigated pose any significant radiological threat to the public.Item NATURAL RADIOACTIVITY IN BOREHOLE WATER OF SOME WARDS IN MINNA, NIGER STATE(2011-01-11) Kolo, M. T.,; Baba-Kutigi A. N.,; OLARINOYE, OYELEKE; Ibrahim. S.28 samples o~ borehole water used for drinking and domestic purposes were sampled from three wards namely Bosso ward (A), Matkunkele ward (B), and Maitumbi ward (C) in Minna city, Niger State. The water samples were analyzed at the Center for Energy Research and Training, CERT, Ahmadu Beilo University Zaria, for their natural radioactivity content, using the Eurisis system-eight-:-channel-gas-filled proportional counter. The results obtained show that none of the samples from the three wards has gross alpha activity higher than the recommended guidelines by World Health Organization (WHO). The beta activity of two samples from ward B and four from ward C, however, shows a little elevation above the recommended screening level for potable water. The elevations notwithstanding, however, the overall results generally show that water from boreholes in the three wards is safe for drinking and other domestic purposes.