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Effect of Si, B, Al2O3 and ZrO2 nano-modifiers on the structural and mechanical properties of Fe + 0.5% C alloy

Karunakaran G., Van Minh N., Konyukhov Y., Kolesnikov E., Venkatesh M., Kumar G. S., Gusev A., Kuznetsov D.

Archives of Civil and Mechanical Engineering

2017

Vol. 17, no. 3

669--676

In the present study, we have incorporated different nanoparticles such as silicon (Si), boron (B), alumina (Al2O3) and zirconium (ZrO2) as modifiers in Fe + 0.5% C alloy to evaluate its influence in it. The properties such as hardness, volume shrinkage/swelling, flexural strength, relative density and fracture analysis of Fe + 0.5% C alloys with and without nanomodifier are also analyzed. The obtained result reveals that incorporation of Si, and B nanoparticles greatly improves the hardness, volume shrinkage/swelling, flexural strength, and relative density of Fe + 0.5% C alloys by increasing grain numbers and reducing the porosity. The SEM analysis of fractured samples clearly showed the involvement of nanoparticles during the alloy formation. Si and B nanoparticles completely entered into the grain and leads to the improvement of structural and mechanical properties of the alloy. However, Al2O3 and ZrO2 nanoparticles are observed on the surface of the grain, which clearly indicates that it does not take part in the alloy formation, which leads to affect its structural and mechanical properties. Thus, this study enlightens the use of nano Si and B as a modifier to enhance the structural and mechanical properties of Fe + 0.5% C alloy via powder metallurgy.

Radiation stability of 125I-brachytherapy sources

Saxena S., Ram R., Dash A., Joshi P., Venkatesh M.

Nukleonika

2007

Vol. 52, nr 1

13-16

Low energy 125I-brachytherapy sources are used for the treatment of retinoblastoma and many other forms of eye cancer. Such sources were prepared by adsorption of 125I on palladium coated silver rods and were critically evaluated for safety aspects, as per AERB standards. In order to attain low leachability and to facilitate leak free laser encapsulation of sources within titanium capsules of size 0.8 mm (f) ´ 4.75 mm (l), the radioactive source core was coated with polystyrene. With a view to study the radiation stability of such sources over a period of three weeks, both polymer coated radioactive sources and inactive source cores were separately subjected to an integrated gamma dose of ~(17.85 ´ 104) Gy (17.85 MRad), which is the dose expected to be received in three weeks from a source containing ~ 111 MBq of 125I. This was carried out to test their suitability for reuse within such period. SEM pictures of inactive source cores were taken to observe the effect of gamma radiation on palladium coating. Post-irradiation leachability and uniformity of activity of radioactive sources were evaluated and found to be satisfactory. The sources were found to be reusable safely, for repeated brachytherapy procedures over a practically useful time of at least three weeks.