Pabna University of Science and Technology

Oxygen vacancies are known to critically influence the crystal structure, electronic properties, as well as photocatalytic performance of double perovskites. In this study, we employ first-principles density functional theory (DFT) with generalized gradient approximation (GGA) and Hubbard U corrections to systematically investigate the effects of oxygen vacancies on Ba2CeMO6 (M = Bi, Sb) double perovskites. The introduction of vacancies significantly modifies the band structure, generating intermediate electronic states that reduce the band gap energy and enhance photocatalytic performance, as evidenced by band edge potential analysis. Effective mass calculation supported the results and displayed lighter mass of charge carriers in the reduction potential. Structural relaxations reveal local distortions around the vacancy sites and exhibit vacancy-mediated phase transition phenomenon. The experimental zero band gap of Ba2CeBiO6 is rationalized by the oxygen vacancy-induced semiconducting to metallic electronic configuration. Thermodynamic calculations indicated high Debye temperature and melting point with minimum thermal conductivity. Furthermore, optical property analysis suggests improved light absorption in the visible range, highlighting the potential of defect-engineered Ba2CeMO6 (M = Bi, Sb) for efficient photocatalytic applications. These results provide fundamental insights into defect-mediated property tuning in perovskite semiconductors, offering to design for next-generation functional materials.

This study develops and evaluates a high-renewable hybrid microgrid for rural Bangladesh. The objective is to design a reliable, affordable, and grid-compliant system that supports residential, institutional, and irrigation loads. The work integrates techno-economic optimization, sensitivity analysis, and voltage-frequency stability assessment within a single framework. HOMER Pro is used to analyze multiple hybrid configurations, while MATLAB evaluates dynamic stability. The proposed contribution lies in modeling realistic field-based load profiles, incorporating converter constraints, and assessing stability across different operating conditions. A PV-wind-biogas-battery microgrid emerges as the optimal option. It achieves 88.2% renewable penetration with a net present cost of USD 206,841 and a levelized cost of energy of USD 0.0207/kWh. Solar PV and wind provide most of the annual energy, while grid support remains limited. Sensitivity analysis shows that solar and converter costs strongly influence project economics. Dynamic simulations confirm secure voltage-frequency performance and compliance with Bangladesh Grid Code limits. The results demonstrate that the proposed system offers a practical pathway for low-cost, reliable, and sustainable electrification in rural communities. The framework can also be adapted to other locations with similar resource and load characteristics.

This paper examines the implementation of Financial Technology (FinTech) in pharmacy retail shops in Bangladesh, utilizing the Technology, Organization, and Environment (TOE) framework. Although FinTech has the potential to transform financial inclusion and the efficiency of businesses of the companies involved in small healthcare-related enterprises, this application has yet to be realized significantly. The study was conducted on 314 pharmacy retailers in eight divisions of Bangladesh by a structured questionnaire, and analyzed in SmartPLS through the Structural Equation Model (SEM). Results indicate that Top Management Support, Organizational Size, and IS/IT Knowledge all have a significant, positive relationship with FinTech integration and that the Relative Advantage relationship is of moderate effect. Complexity turned out to be a key barrier, whereas Compatibility, Regulatory Environment, and Competitive Pressure were of negligible effect. The model indicated 36.7 percent of the variance (R2 = 0.367), indicating a moderate predictive validity. This study is an eye-opener on how organizational readiness, simplification of technologies, and better regulatory prowess are important measures to ensure FinTech integration in pharmacy retailing within the developing world.

This data article introduces a structured pavement surface image dataset developed to advance research in automated pavement condition assessment and data-driven road infrastructure monitoring. The dataset comprises three distinct pavement condition categories: (i) alligator cracking, (ii) edge-breaking distress, and (iii) undamaged (intact) pavement surfaces, each representing a prevalent form of pavement deterioration or intact condition typically observed in flexible pavements. The dataset consists of 12,000 raw images (4000 per class) collected under real-world conditions. These images represent the primary scientific contribution of the dataset. All images were standardized through resizing and normalization, and the dataset was partitioned into training, validation, and testing subsets to ensure reproducibility and consistency in data-driven experiments. Pavement images were collected from selected segments of National Highway N6 in Pabna District, Bangladesh, under natural daylight conditions using a smartphone camera during field surveys. Image acquisition was conducted following standard safety practices without disrupting traffic flow. All images were manually reviewed and labelled to ensure annotation accuracy. This dataset is intended to support research on automated pavement crack detection and classification, benchmarking of computer vision and deep learning models, and the development of lightweight and edge-deployable inspection systems.

The widespread use of synthetic dyes in textiles, paper, paints, and plastics causes severe water pollution by blocking sunlight, reducing photosynthesis, and harming ecosystems and human health. To mitigate this, graphene oxide (GO) was synthesized from waste dry cell electrodes, followed by the preparation of GO-incorporated titanium dioxide/polyaniline (GO/TiO2/PANI) composites. The composites were then characterized for their structural and elemental properties using SEM, EDX, XRD and FTIR. The photocatalytic degradation of congo red dye was systematically examined under varying dye concentrations, pH levels, contact times, and catalyst dosages. At an initial concentration of 8 ppm, 92.7% degradation was achieved within 300 minutes under visible light irradiation at neutral pH. Catalyst dosage significantly influenced performance, with concentrations of 3, 5, 7, and 10 mg per 100 mL of an 8 ppm dye solution yielding degradation efficiencies of 80–85%, 92–95%, 96–98%, and 97–99%, respectively. Furthermore, electrochemical analysis demonstrated markedly enhanced performance, with the ternary composites exhibiting a specific capacitance of 17.50–43.87 F g−1—substantially higher than that of individual GO, PANI, and PANI/TiO2 systems. These findings demonstrate that the synthesized composite possesses enhanced photocatalytic activity, achieving efficient degradation of congo red dye under sunlight at neutral pH. The improved electrochemical performance obtained through GO incorporation further underscores the potential of recycled GO in developing electrode materials for supercapacitor applications. Moreover, the recycling of waste graphite into functional GO-based materials underscores the dual benefit of effective waste reduction and value-added material regeneration, paving the way for future research in environmental remediation and energy storage.