Efficient reservoir operation requires simultaneous consideration of competing goals related to hydropower generation, water-supply reliability, flood management, and storage regulation. However, deriving balanced operating policies becomes increasingly complex when several conflicting objectives are considered concurrently. This study develops a many-objective optimization framework for the Indira Sagar Reservoir, India, considering four objectives: maximization of hydropower generation and minimization of water deficit, spill losses, and storage deviation. The reservoir operation model integrates hydrological inputs, demand characteristics, operational constraints, and reservoir continuity relationships. Five metaheuristic algorithms Non-dominated Sorting Genetic Algorithm II (NSGA-II), Non-dominated Sorting Genetic Algorithm III (NSGA-III), Multi-Objective Particle Swarm Optimization (MOPSO), Multi-Objective Ant Colony Optimization (MOACO), and Multi-Objective Teaching–Learning-Based Optimization (MOTLBO were comparatively evaluated using Hypervolume (HV), Inverted Generational Distance (IGD), and computational performance indicators. NSGA-III achieved an HV of 0.9234 and an IGD of 0.0338, demonstrating effective convergence and diversity for the evaluated solutions. Pareto analysis revealed distinct trade-offs among energy generation, water shortage, spill, and storage regulation. The Weighted Sum Method (WSM) identified Solution S10 as the selected compromise policy, providing 4106.8 GWh/year hydropower generation, 352.9 MCM/year water deficit, and 92.3
Abstract Reinforced concrete (RC) beams frequently require web openings to accommodate building services such as plumbing, electrical conduits, and heating, ventilation, and air-conditioning (HVAC) systems. However, these openings interrupt the natural stress-transfer mechanism, induce stress concentrations, and may reduce the load-carrying capacity and stiffness of beams, particularly when located in critical shear regions. Conventional strengthening methods can involve additional construction work and may be difficult to implement in existing structures. Therefore, an efficient and practical strengthening technique is needed to improve the structural performance of RC beams containing web openings. This study experimentally investigates the influence of circular web-opening size on the structural behaviour of RC beams and evaluates the effectiveness of a mechanically anchored flanged-steel-tube strengthening technique. A total of 33 RC beams were tested under four-point bending, comprising three solid control beams, 15 beams with unstrengthened circular openings, and 15 beams strengthened using flanged steel tubes. The opening diameters ranged from 15 to 75 mm, corresponding to 0.1D-0.5D, where (D) is the overall beam depth of 150 mm. Load-carrying capacity, first-cracking load, midspan deflection, stiffness, and failure behaviour were evaluated. The experimental findings indicate that increasing the opening diameter adversely affects structural performance. The ultimate load decreased from 93.4 kN for the solid control beam to 71.5 kN for the beam with a 0.5D opening. The strengthening technique increased the ultimate load by 2.9–5.6% for opening ratios of 0.2D-0.5D, while the 0.1D configuration exhibited a 1.8% reduction relative to its unstrengthened counterpart. The strengthened beams also exhibited reductions in maximum deflection of approximately 6.1–12.4%. Finite element analysis using ANSYS was conducted to assess the numerical model against the experimental results, with predicted ultimate loads differing from the measured values by approximately 4.2-6.0%. The proposed technique has potential application in the rehabilitation and strengthening of existing RC beams in buildings and other structures where openings are required for building services, subject to further validation under different structural and environmental conditions. The novelty of this study lies in the experimental evaluation of a mechanically anchored flanged-steel-tube retrofit specifically designed for circular web openings, together with a comparative assessment of opening-size effects and experimental-numerical load-carrying behaviour.
Abstract Mild steel (MS) has potential applications in marine structures, pipelines, and industrial equipment; however, corrosion in MS severely limits its performance and durability. Effective protection strategies are therefore required to ensure extended service life and reliable use in practical environments. In this direction, the present study encompasses the controlled preparation of oleic acid-capped hydrophobic sodium ytterbium fluoride nanoparticles (NaYbF₄ NPs) via the hydrothermal method, the multilayer coating of as-prepared NPs on MS substrates via dip-coating, and their structural and electrochemical characterization. Besides, two other sets of MS substrates, one coated with bare oleic acid (OA) and the other with hydrophobic NPs incubated with excess OA, have been prepared and tested. The field emission scanning electron microscopy (FESEM) micrograph shows spherical nanoparticles with sizes of ~ 40–80 nm. FTIR spectrum confirms the successful formation of OA-capped NaYbF 4 nanoparticles via -CH 2 stretching vibrations at ~ 2920 and ~ 2850 cm − 1 . The corrosion behaviors of the dip-coated MS (1–3 layers) are inspected in 0.5 M NaCl by polarization tests, open circuit potential (OCP), and electrochemical impedance spectroscopy (EIS). The OCPs of the coated MS samples are shifted toward more positive voltages; however, the maximum positive shift in OCP of coated samples compared to bare MS has been observed for MS coated with 2 layers of NaYbF 4 NPs. Bode results further confirm superior protection for MS@NPs-2 L, exhibiting the highest impedance and the lowest corrosion current density (i corr ) of 3 µA cm − 2 (93% protection). Notably, OA-incubated NaYbF₄ nanoparticles showed lower water contact angle (WCA) and higher corrosion current density than oleic-acid-capped nanoparticles, indicating altered surface wettability and electrochemical behavior. Corrosion analysis revealed severe corrosion of bare MS, whereas nanoparticle coatings significantly enhanced corrosion inhibition, with the two-layer coating exhibiting the highest inhibition efficiency among the one-, two-, and three-layer coatings. The overall results provide an effective protective strategy against corrosion, offering a promising approach for advanced surface protection of mild steel.
Abstract This study presents a mechanics-based global–local finite element assessment of a field-modified steel truss-box (STB) system in which an originally specified solid wide-flange (WF) column was replaced during construction by a built-up assembly comprising wide-flange tee (WT) and angle (L) sections. The modification changed the local force-transfer path at the beam–column–bracing connection. Although the original project-level analysis indicated satisfactory serviceability and ultimate limit-state performance, the altered configuration required further examination of global stability, local stress concentration, and connection-level yielding. A two-stage finite element analysis was conducted using Strand7. The global model used beam elements to evaluate the overall response of the modified STB system, whereas a detailed plate-element submodel was developed for the critical WF–WT connection. The assessment considered the reference loading condition and a representative additional 10 kN bracing-related perturbation load to investigate the sensitivity of the modified connection to changes in load transfer. The study is limited to a numerical case study and does not include direct experimental validation, detailed bolt pretension and slip modelling, residual stresses, geometric imperfections, or nonlinear fracture simulation. The global analysis showed that the modified system retained an elastic eigenvalue buckling reserve, with a global buckling factor of approximately 16.8. However, the maximum global von Mises stress reached approximately $$1.16f_y$$ at the evaluated ULS deformation, indicating that the response was governed by strength demand rather than global elastic buckling. At the connection level, the WT flange developed maximum von Mises stresses of 469.97 MPa under the reference condition and 483.29 MPa after the bracing-related perturbation, corresponding to approximately $$1.88f_y$$ and $$1.93f_y$$ , respectively. The calculated local shear stresses also exceeded the von Mises pure-shear yield threshold, $$f_y/\sqrt{3}$$ . In contrast, the local eigenvalue buckling factor remained above 3.0 for all evaluated cases, indicating that local yielding, rather than local plate buckling, governed the predicted response within the adopted modelling assumptions. The progressive yielding sequence showed that yielding initiated in the WT flange before extending to the WF end plate, identifying the WT flange as the capacity-controlling component of the evaluated connection. The results demonstrate that a satisfactory global frame response and substantial elastic buckling reserve do not necessarily ensure adequate local connection performance after field modification. The proposed global–local framework provides a transferable mechanics-based approach for identifying vulnerable force-transfer regions and supporting the assessment of similar field-modified steel connections.
Universities play a crucial role in promoting the Sustainable Development Goals (SDGs) through their operations, research, and community engagement. However, current studies on campus mobility remain fragmented, often focusing separately on technological, behavioural, or governance aspects, lacking a unified framework that connects sustainable mobility initiatives to specific SDG outcomes. This study addresses the gap by conducting a systematic review and synthesising evidence from 50 peer-reviewed publications published between 2008 and 2025, examining how university campus mobility initiatives contribute to the Sustainable Development Goals through diverse ideological frameworks. Using a qualitative interpretive synthesis, the study analysed global case studies from Europe, Australia, Latin America, and Africa, categorised around four ideological domains: environmental pragmatism, behavioural change, social justice, and governance partnerships. The results suggest that integrated approaches may support multiple SDG co-benefits, including reduced carbon emissions, improved health and well-being, and more sustainable communities. Nevertheless, recurring barriers across the reviewed studies include institutional inertia, fragmented governance, and infrastructural deficiencies. Based on the reviewed evidence, the study presents a conceptual framework linking ideological foundations, mobility interventions, and SDG outcomes, while recognising that its applicability should be further examined across underrepresented regional contexts. Achieving transformational campus mobility requires paradigm fluency, integrating technological, behavioural, justice-oriented, and governance strategies, thereby reinforcing universities’ leadership in realizing Sustainable Development.
