# Latest Research on Magnetic Radiation : May 21

**[1] Generation of Magnetic Fields in the Radiation ERA**

It is shown that magnetic fields are generated during the radiation era of the early Universe in regions that have rotation. These fields are weak compared with the present intensity of the galactic magnetic field and therefore must be amplified as the Galaxy forms and evolves.

**[2] Radiation Damping in Magnetic Resonance Experiments**

Magnetic resonance experiments can be described by analogy to a coupled pair of circuits, one of which is the ordinary electrical resonant circuit. The other circuit is formed by the rotating magnetization. For transient phenomena, such as occur, e.g., in the pulse techniques of free nuclear induction, the coupling gives rise to a damping of the magnetic resonance by the electric circuit. Such damping can also be considered as spontaneous radiation damping. It is shown that in certain cases of nuclear induction this radiation damping is more important than the damping from the spin-spin and the spin-lattice relaxation mechanisms usually considered. For ferromagnetic materials at microwave frequencies the radiation damping can become very large.

**[3] Measurement of radiation dose distributions by nuclear magnetic resonance (NMR) imaging**

A method is described for determining the spatial distribution of radiation dose in a tissue-equivalent phantom using nuclear magnetic resonance imaging. The conversion of ferrous ions to ferric by ionising radiation alters the magnetic moment and electron spin relaxation times of the metal ion. The spin relaxation times (T1 and T2) of the hydrogen nuclei in an aqueous solution of a ferrous salt are consequently reduced substantially. These changes in T1 and T2 can be measured using standard NMR techniques. The same conversion is used in conventional Fricke dosimetry, which can be used to calibrate the technique.

**[4] Combined Effects of Hall Current and Magnetic Field on Unsteady Flow Past a Semi-infinite Vertical Plate with Thermal Radiation and Heat Source**

In the present study combined effects of Hall current and magnetic field on unsteady laminar boundary layer flow of a chemically reacting incompressible viscous fluid along a semi-infinite vertical plate with thermal radiation and heat source is analyzed numerically. A magnetic field of uniform strength is applied normal to the flow. Viscous dissipation and thermal diffusion effects are included. In order to establish a finite boundary condition () instead of an infinite plate condition, the governing equations in non- dimensional form are transformed to new system of co-ordinates. Obtaining exact solution for this new system of differential equations is very difficult due to its coupled non-linearity, so they are transformed to system of linear equations using implicit finite difference formulae and these are solved using ‘Gaussian elimination’ method and for this simulation is carried out by coding in C-Program. Graphical results for velocity, temperature and concentration fields are presented and discussed. The results obtained for skin-friction coefficient, Nusselt and Sherwood numbers are discussed and compared with previously published work in the absence of Hall current parameter. These comparisons have shown a good agreement between the results. A research finding of this study, achieved that the velocity and temperature profiles are severely affected by the Hall effect and magnetic field and also a considerable enhancement in temperature, main and secondary flow velocities of the fluid is observed for increasing values of radiation parameter.

**[5] A Survey of Radiation Levels Associated with Exposure to Power-line in Some Selected Areas in Ibadan Metropolis, Oyo State, Nigeria**

Measurement of electric field strength, magnetic field strength and power density were carried out using two instruments, electro smog meter (model TES -92) and ELF detection meter (model 480823) at an interval of 2 m starting from the base of the source. The maximum electric field strength, magnetic field strength and power density obtained in this research are 5.09 V/m, 0.2037 A/m and 0.5002 W/m2 respectively. Three of 132 KVA are located at three different communities, Ayede/Jericho, IITA and Ojoo, and three of 11 KVA are also located at three different communities, Odo – Ona, State secretariat and Sango- UI. The maximum electric field strength, magnetic field strength and power density measured as radiated from 132 KVA are 5.09 V/m, 0.0135 A/m and 0.500 W/m2 (Ayede/Jericho), 3.535 V/m, 0.003694 A/m and 0.06874 W/m2 (IITA), 1.3284V/m, 0.00942 A/m and 0.00457 W/m2 (Ojoo) respectively. Also, the maximum electric field strength, magnetic field strength and power density measured as radiated from 11 KVA are 0.0658 V/m, 0.02037 A/m and 0.0006278 (Odo- Ona), 1.619 V/m, 0.00393 A/m and 0.0696 W/m2 (State secretariat), 0.6046 V/m, 0.00225 A/m and 0.00155 W/m2 respectively. These results constitute 0% of the recommended values by the ICNRP. Therefore, peoples living or carrying out other activities along power lines at these sites will not suffer any health hazards due to electromagnetic radiations emanating from the power lines.

**Reference**

**[1] **Harrison, E.R., 1970. Generation of magnetic fields in the radiation era. *Monthly Notices of the Royal Astronomical Society*, *147*(3), pp.279-286.

**[2] **Bloembergen, N. and Pound, R.V., 1954. Radiation damping in magnetic resonance experiments. *Physical Review*, *95*(1), p.8.

**[3] **Gore, J.C. and Kang, Y.S., 1984. Measurement of radiation dose distributions by nuclear magnetic resonance (NMR) imaging. *Physics in Medicine & Biology*, *29*(10), p.1189.

**[4] **Srihari, K., 2015. Combined effects of Hall current and magnetic field on unsteady flow past a semi-infinite vertical plate with thermal radiation and heat source. *Physical Science International Journal*, pp.73-89.

**[5] **Haruna, A. and Oladayo, O.R., 2016. A Survey of Radiation Levels Associated with Exposure to Power-line in Some Selected Areas in Ibadan Metropolis, Oyo State, Nigeria. *Physical Science International Journal*, pp.1-6.