Robert R. Dawam

Bio: Robert R. Dawam is an academic researcher. The author has contributed to research in topics: Viscosity & Equivalent dose. The author has an hindex of 1, co-authored 2 publications receiving 13 citations.

Assessment of Indoor and Outdoor Background Radiation Levels in Plateau State University Bokkos Jos, Nigeria

Abstract: Survey taken by the world health organization (WHO) and the international commission on radiation protection (ICRP) shows that residents of temperate climate spends only about 20% of their time outdoor and about 80% indoors and certain materials use for the construction of such buildings (rocks soils) are known to be radioactive. This work set out to assess the background ionizing radiations at Biochemistry, Chemistry, Microbiology and physics laboratories all of Plateau State University Bokkos to determine the radiation levels both within the laboratories and their immediate surroundings. The gamma-scout used for the purpose of the study was adjusted to detect the alpha, beta and gamma types of radiation in ?Sv/hr. The mean equivalent dose rate per hour for indoor background radiation for the laboratories was found to be 0.256?Sv/hr while the outdoor was 0.249?Sv/hr. The mean annual equivalent dose rate of the laboratories were compute for indoor and outdoor background radiation level to be 1.54mSv/yr and 0.44mSv/yr respectively, and are in a good proportion below the world wide average dose of 2.4mSv/yr. Keywords : Cancer,equivalent, dose rate, gamma-scout, background ionizing radiation.

Use of viscometer for monitoring purities of clinical solutions

Abstract: The activation energy, E a of an original pure liquid should change when a solute molecule is added to it since the addition may change the bond strength of the given liquid molecule as the impurity (solute) molecules tend to occupy the neighboring positions in the liquid. The change in E a is expected to be affected significantly by addition of impurity molecules and thus the viscosity coefficient and the time of flow of the mixture through a capillary tube. Monitoring purity level (concentration levels) of clinical intravenous fluids is very important for safety of patients. In this paper we study using a simple viscometer the viscosity coefficients of clinical Dextrose and Sodium Chloride solutions. We find that the viscosity, at 30.5 0 C, of dextrose solution with concentration range from 2.0% to 20.0% varied from 8.71 x 10 -4 Pa.s to 13.32 x 10 -4 Pa.s within an error of ±0.1%. For sodium chloride solution with concentration range from 1% to 10%, viscosity coefficient varied from 8.91 to 10.41x10 -4 Pa.s. With distilled water as a standard and using the concept of reduced time ratio of flow and the observed data, we find that the viscometer can be very reliably used to measure concentration of any unknown clinical Dextrose and Sodium Chloride solutions. From the measured data we also determine the positive changes of activation energy of the two types solutions with increase in solute concentrations. We recommend further measurements at three different temperatures which shall enable us to determine the absolute values of the activation energies of the two solutions of different concentrations. We present necessary theoretical analysis so that with the data, any viscometer can then be used as a reliable liquid purity(Dextrose and Sodium Chloride solutions) analyzer. The data can also be used to study variation of molecular properties of solutions with concentrations of solute. The latter studies can find applications in solution chemistry. Key words: Viscometer, Concentration, Activation energy, viscosity coefficient, clinical solutions, reduced time ratio.

General Properties of Matter

Abstract: This chapter summarises some important ideas about vapours and liquids, including Raoult’s law, diffusion and effusion of gases and the effect of a solute on the freezing point and boiling point, together with that on the osmotic pressure, of a solution. In areas where some difficulty is often encountered, rather more than a simple summary is given.

Assessment of Indoor Ionizing Radiation Profile in Radiology Department FMC Asaba Delta State, Nigeria

Abstract: A “Radiation Alert Inspector” survey meter was the instrument of choice used in measuring and obtaining the indoor ionizing radiation profile placed at 22 selected presumable hotspots of increase radiation (coded A1-A22) as identified by a global positioning system within the Radiology department of Federal Medical Centre (FMC) Asaba. Values obtained from the measurements were converted from micro Sievert per hour (μSv/hr) to mili Sievert per year (mSv/yr). The calculated mean indoor post exposure dose value was in the range of 0.09 – 0.20 μSv/hr (0.60-2.01 mSv/yr). The highest point with increased radiation dose was found to be in the diagnostic x-ray room (2.01±4.11 mSv/yr), while the lowest point was detected at the intern’s common room with a value of 0.60±0.3 mSv/yr. The overall mean of the Mean Indoor Post Exposure (mMIPE) was arrived at 0.88±0.28mSv/yr. Base on the aforementioned findings, it was deduced that radiation level were kept within permissible radiation limit as stipulated by the ICRP and UNSCEAR of 1mSv/yr and thus, FMC Asaba can be said to be Radiologically safe.

Natural Radioactivity Concentration And Effective Dose Rate From Jos Tin Mining Dumpsites In Rayfield, Nigeria

Abstract: The International Commission on Radiological Protection (ICRP) has recommended the annual effective dose equivalent limit of 1mSvy -1 for the individual members of the public and 20mSvy -1 for the radiation workers. The assessment of naturally occurring radio nuclides 226 Ra, 232 Th and 40 K in nine major tin mine dumpsites in and closely around Rayfield area of Jos Plateau were carried out using gamma-ray spectrometry with NaI(Tl) detector to determine the natural radio nuclide in the dumpsites and to evaluate the hazards these might have on the public. The calculated average activity concentration of 226 Ra, 232 Th and 40 K in the samples were 132.6±21.4, 351.4±20.9 and 319.6±37.7 Bqkg -1 respectively. The mean activity concentration of 226 Ra and 232 Th in the present study is much higher than the world-wide average values of 33 Bqkg -1 and 45 Bqkg -1 respectively but the mean concentration of 40 K is lower compared to the world average of 420 Bqkg -1 . The present study revealed that the calculated average absorbed dose rate, radium equivalent dose, indoor annual effective dose rate and outdoor annual effective dose were found as 293.27nGyh -1 , 569.68mSvy -1 , 1.44mSvy -1 and 0.34mSvy -1 respectively. The mean values of the absorbed dose rate, radium equivalent dose and the indoor annual effective dose rate are much higher than the world average recommended safety limits. Therefore it can be concluded that the present study area is radiologically unsafe from radiological hazards and will pose harmful effects to the environmental and the living population. However, no significant radiological impact have been observed on the surrounding environment and the living population, this might be attributed to the higher value of the Nigeria annual effective dose of 0.098 mSvy -1 compared to the world annual effective dose of 0.07mSvy -1 . Keywords: Radioactivity, Effective dose, Tin mining, Dumpsites.

Determination of Background Ionizing Radiations in Selected Buildings inNairobi County, Kenya

Abstract: A survey taken by the world health organization (WHO) and the international commission on radiation protection (ICRP) shows that certain materials used for the construction of such buildings (rocks soils) are known to be radioactive. Exposure to indoor ionizing radiation like exposure to any other type of ionizing radiation results in critical health challenges. This work set out to determine the levels of background ionizing radiations in selected buildings around Nairobi County and its environs. The Radiation Alert R (Digilert 200) meters were used to capture the readings. The meters were held about 1 m above ground level and readings were recorded in mR/h for all buildings. Numerical data was subjected to analysis of variance using Minitab version 17.0 to determine the statistical differences of exposure levels within various areas. A total of 400 buildings were sampled. The annual indoor readings were highest in Eastleigh (4.070 mSv) and relatively lowest in Nairobi Central Business District (CBD) at 2.763 mSv, representing a deviation from WHO recommended standard of 307.0% and 176.3%, respectively. None of the buildings sampled had exposure levels below the WHO recommended standard of 1 mSv. Overall, these results indicate presence of higher levels of ionizing radiations in buildings beyond the acceptable annual threshold thereby posing significant health risk to the public. Consequently, these results could find great application in guiding the formulation of the national building code to include routine surveillance of the background ionizing radiation levels in various buildings to assess the health risk of general public as well as exploring appropriate mitigation approaches.

Preliminary investigation of the ambient radiation levels of mining sites in Benue State, Nigeria

Abstract: The study of the ambient radiation levels around some mining sites in Benue State has been carried out using radiation meters; Inspector 06250 and Dose Meter 6150AD. A total of four mining sites were selected for measurements. These sites include the Guma salt mine, Makurdi clay mine, Mkar quarry in Gboko and the Otukpo clay mine. The values of the dose equivalent rates obtain ranged from 0.18 to 0.33mSv/yr and the value of the exposure rate range from 0.011 to 0.11mR/hr. Activity values range from 2.7 to 5.1kBq. The results show that the Mkar quarry recorded the highest values of dose equivalent rate of 0.330.003mSv/yr, exposure rate of 0.10.002mR/hr and activity of 2.70.4kBq. Results show that all the mining locations are still within the safety limits of 1.0mSv/yr, as set by the International Commission on Radiological Protection (ICRP). Keywords : Ambient, radiation, dose, exposure, activity. Nigerian Journal of Physics Vol. 18 (2) 2006: pp. 219-222