Poly(acrylamide co-acrylic acid) hydrogels were prepared by free-radical copolymerization of acrylamide and acrylic acid in aqueous solutions using electron beam irradiation in the dose range of 2.5 kGy to 6 kGy in atmospheric conditions and at room temperature. The influence of the absorbed dose, the amount of cross-linker (trimethylolpropane trimethacrylate) and initiator (potassium persulfate) on the swelling properties and the diffusion coefficient and network parameters of hydrogels were investigated. The structure and morphology of hydrogels were characterized by Fourier Transform Infrared Spectroscopy (FTIR) and Scanning Electron Microscopy (SEM). The use of the obtained hydrogels by the removal of Cu2+ and Cr6+ from aqueous solutions was investigated at room temperature. During the adsorption of metal ions on hydrogels, the residual metal ion concentration in the solution was measured by an atomic absorption spectrophotometer (AAS). It has been established that the use of a relatively small amount of trimethylolpropane trimethacrylate for hydrogel preparation has led to the increasing of swelling up to 8500%.

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Concrete of various type have been used extensively for the adequate shielding of the radiological equipment using X and gamma rays. In its basic form, concrete is composed of pieces of inert aggregate held together by hardened cement paste. Dierent concrete types with special cements have been prepared. The linear attenuation coecients of conventional concrete and concrete with supplementary mineral additives (barite and witherite) at dierent gamma energies (Co-60: 1.25 MeV, Cs-137: 0.662 MeV, Ir-192: 0.37 MeV) in narrow beam conditions have been measured. This paper includes some experimental data regarding the inuence of barite and witherite additives on photon attenuation coecients of concrete.

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