Nuclear and Radiation

A second order partial differential equation occurring frequently in applied mathematics is the wave equation. A generalization of this equation inevitably arises in many mathematical analyses of phenomena involving the propagation of waves in continuous media. Here, we applied the wave differential equation to investigate and explain neural communication using the nervous system. On application of Bloch nuclear magnetic resonance theory, a linear 1-dimensional homogeneous second order partial differential equation, as a model, is obtained which represents a nerve set in a vibrational motion. Analytical results from the solution of the differential equation show that the transmission of nerve impulses is not a flow of electrons, as in the case of electric current, but a wave of electrical activity travelling along the neurone. A three dimensional pictoral representation of the results further explains the phenomenon clearly.

An evaluation of 238U, 235U, 137Cs and 133Xe in soils from two campuses in university of Douala-Cameroon using gamma spectroscopy based Broad Energy Germanium Detector (BEGe6530) has been performed. The mean activities in soils from Campuse 1 were 40.16±8.98 Bq/kg for 238U, 3.39±0.33 Bq/kg for 235U, 0.46±0.33 Bq/kg for 137Cs and 0.14±0.16 Bq/kg for 133Xe. In Campus 2, the mean activities in soils were 31.45±12.24 Bq/kg, 3.02±1.00 Bq/kg, 0.30±0.26 Bq/kg and 0.35±0.24 Bq/kg for 238U, 235U, 137Cs and 133Xe respectively. Using the In situ survey meter, the mean values of the absorbed dose rate measured was 71.43 nGy/hr for Campus 1 and 62.72 nGy/hr for Campus 2. The evaluated average outdoor effective dose for Campus 1 and 2 were 87.60 µSv/yr and 76.93 µSv/yr respectively. The overall results obtained in this work were generally low compared to that of UNSCEAR.

In this work, the natural radionuclide contents of some building materials widely used in Nigeria were measured by the means of gamma-ray spectrometry using Na(I)Tl detector. A total of 15 samples were assayed from different materials. The mean of 226Ra, 232Th and 40K concentrations determined are 30.35±8.69BqKg-1, 20.12±6.00 BqKg-1 and 241.95±76.31 BqKg-1 respectively. These values were lower than permissible global values except for potassium which is higher than that of global permissible value of 52.2, 41.0 and 230.0 (BqKg-1 ) respectively by UNSCEAR. The obtained mean absorbed dose rate for all the collected building materials samples is 39.90(nGgh-1). These results, along with the results of the estimated annual effective dose rates, radium equivalent (Raeq), external hazard index (Hex) are presented and they are found below the internationally accepted safe limits. It suffices to say therefore the analyzed samples could be used for building and construction purposes. It is safe to say that there is no threat pose to any users of the materials.

The aim of the present study is to investigate the rectal dose during three different radiotherapy techniques of cervical cancer. The study was carried out using a Anderson Rando female phantom. The thermo-luminescent dosimeter (TLD) capsules and detectors of rainbow dosimeter were employed for rectal and target volume dose determination. Several techniques of external beam radiation therapy such as two-field (AP-PA), three-field and four-field with equal applied dose were planned. During application of different radiotherapy techniques, the maximum dose received by rectum is due to the two-field technique. The results of two dosimetry types were compared with each other, In three-field, four-field equal applied dose, rectal dose was lower than tumor dose. This study showed that using TLD and rainbow dosimetry during radiotherapy could have a useful role as a predictor of choosing appropriate technique for preventing future rectal complications. Dose limitation to the rectum could possibly be achieved by using three-field and four-field techniques with equal tumor dose while maintaining a high dose to the tumor.

The synthesized 4-hydroxy Coumarin was investigated for the purpose of developing a new chemical ?-radiation dosimeter. The compound was exposed to 60Co ?-radiation source at room temperature. The compound dosimeter exhibited good sensitivity to ?-radiation of dose less than 30 Gy and a fairly good linearity of response in dose range 0-25Gy. The present compound may be used as sensitive, and as well as cost-effective dosimeter in 0-25Gy ?-radiation environment.