Manganese ferrite spinel has been synthesized by using low grade manganese ore and ferric oxide as sources of manganese oxide and iron oxide through solid state reaction route by taking manganese and iron mole ratio of 1:2 respectively. The impact of sintering temperature on phase composition and particle size is investigated. Similarly, the impact of frequency on dielectric constant, dielectric loss, AC (alternating current) conductivity and tangent losses is also investigated. The results shows the presence of spinel structure manganese ferrite (MnFe₂O₄) as the major phase for the sample sintered at 1200 °C. It has been established that the crystallite size increase with rise in sintering temperature. The surface morphology of the sample sintered at 1200 °C show pyramidal and triangular shape grains. The dielectric constant (εʹ) and dielectric losses (εʹʹ) were observed to decrease with increasing the sintering temperature and frequency. Furthermore, the AC (alternating current) conductivity was found to rise with rise in applied frequency. On the other hand, the tangent losses falls considerably with rise in applied frequency.

In this paper, CaCO₃ waste marble dust (WMD) has been utilized in the production of concrete. Raw materials (Cement, Sand, WMD and Crush) were collected from Peshawar, Khyber Pakhtunkhwa, Pakistan. Concrete cubes were molded in the laboratory and investigated by XRD. Effect of WMD addition to the concrete was studied. It was reported that 10% addition of WMD as cement replacement showed enhanced performance of the compressive strength as compared to sand replaced WMD blended concrete. Increment in WMD contents beyond 10% resulted in significant decrement of compressive strength. Substituting WMD with cement resulted in a decrement of 29.76%, while with sand, the decrement was 6.09%. Concrete made with cement replaced WMD showed the lowest water absorption rate over 7 days curing as compared to sand replaced (intermediate water absorption) and clean concrete (highest water absorption) samples. Graphical Abstract

In medical and nuclear plants as well as industrial plants, radiation shielding materials are necessary and concrete composites are popular because they are structurally stable and economically viable. In this paper, the attenuation characteristics of barite-based concrete composites using gamma-rays were experimentally measured and compared with theoretical values. Five concrete samples with the thickness 1–5 cm, using 32.4% barite (BaSO₄) as high-density aggregate, were prepared and irradiated with 1.25 MeV gamma photons of a ⁶⁰Co source. The radiation sent through the ionization chamber was measured with the help of an ionization chamber-electrometer system and linear attenuation coefficient (µ) and mass attenuation coefficient (µ/ρ) were calculated. The experiment results indicated that µ depended on sample thickness and density depending on small differences of compaction, and µ/ρ was relatively constant across all samples. The experimental mass attenuation coefficients were found to be 0.0533–0.0548 cm²/g with high agreement to the theoretical values in the NIST XCOM database with the mean deviation of 0.67% and RMSE of 1.16. The half-value and tenth-value layers (HVL and TVL) were 4.32510 cm and 14.341695 cm respectively, which represented successful gamma attenuation. The optimized specimen was characterized mechanically and gave a compressive strength of 19.58 MPa and a Young modulus of 43.5 Gpa which showed sufficient structural performance in shielding. These findings prove barite addition as a successful technique in improving gamma attenuation and still achieving acceptable mechanical properties. These results are experimentally proven to give the use of barite-based concrete as viable shielding media to regulated radiation atmosphere.