Vertically aligned catalysts comprised of platinum–nickel thin films on nickel nanorods (designated as Pt–Ni@Ni-NR) with varying ratios of Pt to Ni in the thin film were prepared by magnetron sputtering and evaluated for their oxygen reduction reaction (ORR) activity. A glancing angle deposition (GLAD) technique was used to fabricate the Ni nanorods (NRs) and a small angle deposition technique for growth of a thin conformal coating of Pt–Ni on the Ni-NRs. The Pt–Ni@Ni-NR structures were deposited on glassy carbon for evaluation of their ORR activity in an aqueous acidic electrolyte using the rotating disk electrode technique. The Pt–Ni@Ni-NR catalysts showed superior area-specific and mass activities for ORR compared to those of Pt–Ni alloy nanorod catalysts prepared using the GLAD technique and compared to those of conventional large-surface area Pt and Pt–Ni alloy nanoparticle catalysts.

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The activity levels of (226)Ra, (232)Th and (40)K were determined using gamma-ray spectroscopy in different commercial brands of cement, sand and hollow concrete bricks, which were collected from the building material suppliers of Dhaka City. The activity concentrations in the samples were found to be somewhat higher than in other countries. An effort has been made to assess the radiation hazard associated with these materials by determining the gamma activity concentration index I. It was found that the value of I for all the samples was

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