Bangladesh Atomic Energy Commission is a scientific research organization and regulatory body of Bangladesh. Its main objective is to promote use of atomic energy for peaceful purposes It was established on 27 February 1973, after the independence of Bangladesh, the Pakistan Atomic Energy Commission no longer having jurisdiction.
Chalcogenide perovskites such as BaZrS3, which is abundant on Earth and forms a perovskite-type structure, have drawn noticeable attention for photovoltaic (PV) applications due to their nontoxic nature and offer excellent environmental stability. It demonstrates an ideal band gap, making it suitable as an absorber layer in PV devices. In this study, BaZrS3-based chalcogenide perovskite solar cells were simulated using the SCAPS-1D software. The behavior of various parameters in photovoltaic devices was explored to examine their impact on device outputs and improve solar cell efficiency. A variety of hole transport layers (HTLs), including CdTe, PTAA, C6TBTAPH2, and MoO3, were tested with PC60BM as an electron transport layer (ETL). After device optimization, the proposed device configuration is FTO/PC60BM/BaZrS3/MoO3/Au. Optimized device achieves power conversion efficiency (PCE) of 18.15
Concept erasure serves as a vital safety mechanism for removing unwanted concepts from text-to-image (T2I) models. While extensively studied in U-Net and dual-stream architectures (e.g., Flux), this task remains under-explored in the recent emerging paradigm of single-stream diffusion transformers (e.g., Z-Image). In this new paradigm, text and image tokens are processed as a single unified sequence via shared parameters. Consequently, directly applying prior erasure methods typically leads to generation collapse. To bridge this gap, we introduce Z-Erase, the first concept erasure method tailored for single-stream T2I models. To guarantee stable image generation, Z-Erase first proposes a Stream Disentangled Concept Erasure Framework that decouples updates and enables existing methods on single-stream models. Subsequently, within this framework, we introduce Lagrangian-Guided Adaptive Erasure Modulation, a constrained algorithm that further balances the sensitive erasure-preservation trade-off. Moreover, we provide a rigorous convergence analysis proving that Z-Erase can converge to a Pareto stationary point. Experiments demonstrate that Z-Erase successfully overcomes the generation collapse issue, achieving state-of-the-art performance across a wide range of tasks.
Humans are constantly exposed to radiation from their natural environment including soil and gamma radiation has harmful effects on them, so determination of radioactivity concentration in soil are very important. The present study aims to measure the activity concentrations of naturally occurring radionuclides 226Ra, 232Th, and 40K in urban soil samples collected from thirty different areas of Dhaka city. The analyzed was performed using a High-Purity Germanium (HPGe) gamma-ray spectrometer. The results showed that the mean activity concentrations of 226Ra, 232Th, and 40K were found 24.2 ± 1.0 Bqkg-1, 52.0 ± 2.0 Bqkg-1, and 352 ± 11 Bqkg-1, respectively. The average concentrations of 226Ra and 40K fall below the internationally recommended safety limits of 35 Bqkg-1 and 400 Bqkg-1, respectively, while 232Th value exceeded the recommended limit of 30 Bqkg-1 by approximately 1.7 times. The mean value of radium equivalent activity (Raeq) was calculated as 125.7 Bqkg-1, which was far below the global safety threshold of 370 Bqkg-1. The estimated outdoor effective dose rates were 0.070 mSvy-1 and below the worldwide recommended limit of 1 mSvy-1. Additionally, excess life time cancer risk (ELCR) was below than the internationally accepted limit of 0.29 × 10-3. All things considered, the study is the first comprehensive dataset of urban soil in the area and revealed that there are no immediate health dangers due to the low radioactive hazard indices.
The contamination of water by synthetic dyes such as Malachite Green (MG) remains a pressing environmental challenge due to their carcinogenic, mutagenic, and genotoxic effects. In this work, a zinc-supported hydroxyapatite/nickel ferrite (Zn/HAP/NiFe2O4) nanocomposite was synthesized via a hydrothermal route and systematically characterized for its catalytic efficiency in degrading MG. X-ray diffraction confirmed the coexistence of hexagonal HAP and cubic spinel NiFe2O4 phases, with zinc incorporation enhancing crystallinity and active site density. FTIR spectra validated the presence of phosphate, hydroxyl, and metal-oxygen vibrations, while magnetic measurements demonstrated the composite's recoverability using an external magnet. Catalytic degradation experiments revealed that H2O2 alone achieved only similar to 10 % MG removal after 120 min, whereas Zn/ HAP/NiFe2O4 achieved 82.65 % degradation under identical conditions. Kinetic analysis indicated a first-order reaction with a rate constant of 0.01499 min(-1) (R-2 = 0.97). Recyclability tests showed excellent stability, with similar to 80 % efficiency retained after five cycles. Comparative evaluation with other ferrite-based catalysts highlighted the competitive performance of the Zn/HAP/NiFe2O4 composite at low catalyst loading (0.2 mg/L). The synergistic role of zinc in stabilizing Fe2+ ions and promoting hydroxyl radical generation was identified as the key factor. These findings demonstrate the composite's promise as a cost-effective, reusable catalyst for advanced wastewater treatment.
Perovskite solar cells (PSCs) based on lead have achieved a record power conversion efficiency (PCE) in recent years; however, the toxicity and stability of Pb, especially of CH3NH3PbI3, limits its commercialization. As a result, much effort is being put into developing lead-free PSCs. This paper compares the performances of different types of lead-free PSCs and their choice of absorber materials using Solar Cell Capacitance Simulator-1D simulations. In this context, the use of MASnI3, MASnBr3, and MABiI3 as solvent-processed absorbers and their effects on Voc, Jsc, fill factor, and PCE are discussed in this part of the study snippets series. MASnI3 shows the best comprehensive cell efficiency with a maximum PCE of 30.04%. Similarly, MASnBr3 and MABiI3 deliver high performance, with maximum PCEs of 29.19% and 27.97%, respectively, obtained at optimized absorber thicknesses. The outcomes demonstrate the effect of the thickness of the absorber layer, the doping concentration, and the defect density on the performance of the device, revealing that the device with MASnI3 has proved superior performance under the above parameters. Additionally, it elaborates on the enhancement strategies for the hole transport layer and electron transport layer, propagating the idea that defect density at interfaces must be minimized. This study contributes to the ongoing efforts to make highly efficient, lead-free PSCs a practical reality while aiding in sustainable energy conversion and storage.
