Faculty Publications

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Publications by NITK Faculty

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    Closed-Loop Vector Formulation in Euler’s Complex Numbers for Multi-Loop Planar Mechanisms With N-bars: A Novel Modeling Approach and Algorithm
    (Defense Scientific Information and Documentation Centre, 2023) Rahul, V.M.; Bhaktha, B.S.; Gangadharan, K.V.
    This paper presents a novel iterative algorithm incorporated in a user-friendly GUI for modeling the kinematics of multiple looped N-bar closed-loop mechanisms. Past research works have used custom coding or expensive commercial software to analyze the mechanisms of specific applications. The proposed algorithm focuses on kinematics and offers a quick, easy-to-use, cost-effective solution to analyze a wide range of generic mechanisms, reducing the need for custom coding and lowering computational costs. The algorithm employs algebraic equations, such as solving complex closed-loop vector equations using the Euler form of complex numbers, to simulate and derive the unknowns necessary to characterise any generic closed-loop mechanism. The Python code implemented in the algorithm adapts to various scenarios by utilising available information on the position, velocity, and acceleration variables of the mechanisms. The simulation tool can display real-time color contour plots (RGB color scale) for linear and angular velocities and accelerations, simulate mechanisms with multiple loops and switch configurations, and find inverse mechanisms. The approach for solving multiple loop problems and the algorithm utilized to solve the configurations, methods, equations used and GUI features implementation are all described in this study. The case study considered for a four-bar mechanism indicates a strong agreement between the results obtained from the proposed kinematics-based simulator and ANSYS software. These results demonstrate the simulator’s effectiveness in providing low-cost and user-friendly simulation results for various generic mechanisms involving multiple interconnected loops. © 2023, DESIDOC.
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    Ketalization of carbohydrate-derived levulinic esters using cellulose sulfuric acid as a heterogeneous catalyst: a closed-loop biorefinery approach
    (Royal Society of Chemistry, 2025) Prabhakar, P.S.; Dutta, S.
    Levulinic ester ketals (LEKs) are carbohydrate-derived renewable chemicals with potential applications as chemical building blocks, fuel additives, solvents, monomers, and plasticizers. This work reports the synthesis of ethyl levulinate ethylene glycol ketal (LEK 1) and ethyl levulinate propylene glycol ketal (LEK 2) by the ketalization of carbohydrate-derived ethyl levulinate using cellulose sulfuric acid (CSA) as an efficient and recyclable heterogeneous acid catalyst. Cyclohexane was used as the solvent to remove water formed in the reaction by azeotropic distillation, and nearly quantitative isolated yields of LEK 1 and LEK 2 were obtained under optimized parameters. The transformation was optimized on various process parameters, and the CSA catalyst was successfully recycled. Using CSA as a catalyst for producing LEKs shows promise for a closed-loop carbohydrate-centric biorefinery approach. © 2025 The Royal Society of Chemistry.