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Nepal has a long history of medical radiology since1923 but unfortunately, we still do not have any Radiation Protection Infrastructure to control the use of ionizing radiations in the various fields. The objective of this study was an assessment of the radiation protection in medical uses of ionizing radiation. Twenty-eight hospitals with diagnostic radiology facility were chosen for this study according to patient loads, equipment and working staffs. Radiation surveys were also done at five different radiotherapy centers. Questionnaire for radiation workers were used; radiation dose levels were measured and an inventory of availability of radiation equipment made. A corollary objective of the study was to create awareness in among workers on possible radiation health hazard and risk. It was also deemed important to know the level of understanding of the radiation workers in order to initiate steps towards the establishment of Nepalese laws, regulation and code of radiological practice in this field. Altogether, 203 Radiation workers entertained the questionnaire, out of which 41 are from the Radiotherapy and 162 are from diagnostic radiology. The radiation workers who have participated in the questionnaire represent more than 50% of the radiation workers working in this field in Nepal. Almost all X-ray, CT and Mammogram installations were built according to protection criteria and hence found safe. Radiation dose level at the reference points for all the five Radiotherapy centers are within safe limit. Around 65% of the radiation workers have never been monitored for radiation. There is no quality control program in any of the surveyed hospitals except radiotherapy facilities.

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The thermodynamic properties, such as free energy of mixing, heat of mixing, entropy of mixing, activity and microscopic properties, such as concentration fluctuation in long wavelength limit, chemical short range order parameter, ratio of mutual and intrinsic diffusion coefficients of AlÀFe in liquid state at 1873 K have been studied on the basis of regular associated solution model. The complex Al 3 Fe is supposed to be energetically favoured in the liquid solution which is evident from the phase diagram of AlÀFe alloys. Thus the liquid mixture is treated as the ternary solution of complex and unassociated components. The concentrations of the complex Al 3 Fe and unassociated atoms have also been estimated. The concentration fluctuation in long wavelength limit is less than ideal values in whole range of concentration indicating that the system is ordered at all compositions. Our theoretical analysis suggests that the melt is strongly interacting hetero-coordinating system. The interaction energy parameters are all found to be large negative and temperature dependent.