Faculty Publications
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Item Effect of drilling parameters on Neem wood veneer epoxy composites using grey relational analysis(Elsevier Ltd, 2019) Jaiprakash, M.; Nagamadhu, M.; Karthikeyan, K.; Kiran; Shariff, M.; Kumar, G.C.In recent trend the composites based wood are replacing the normal wood and other materials in various fields. The wood composites have cosmic properties like cheaper in cost, denser, free from defect, they can be machined in any way to make desired output product. This paper is all about investigation of wood properties and its behavior for drilling process. Drilling is one of the universal machining process that being carried out in the world.The purpose of drilling is to remove the excess of material from the work piece (specimen) to produce a hole and drilling is the primary process that need to be carried on the specimen to perform other machining operation (boring, reaming and tapping) as drilling got various level of importance in different applications, studying about drilling process and its parameter on different materials is important. This paper is all about the analysis of different drilling parameters such as feed rate (mm/min), spindle speed (rpm), Drill diameter on the quality of drilled hole. To study these factors Grey relation technique and Taguchi analysis is implemented. The result shows that feed rate is the major influencing parameter when compared to other cutting parameter and by selecting the optimal value,the quality of the drilled hole can be improved. © 2019 Elsevier Ltd.Item Multi-port Converter Topology for Simultaneous Power Conversion of Buck/Boost and Inversion operation(Institute of Electrical and Electronics Engineers Inc., 2022) Gangashetty, P.A.; Karthikeyan, K.Multiport converters are given more importance for different applications due to the advantages such as high efficiency, high power density and low cost. Each multiport converter topology has different number of power processing stages, different number of switches and different control techniques. This paper proposes a single-stage multiport power converter topology for integrating PV-Battery to the three phase ac load application. Power flow between all the three ports are managed using Finite Control Set Model Predictive technique. The proposed converter has reduced number of switches and conversion stages to connect PV and battery to the three phase ac load system compared to conventional switches. The converter topology is based on bidirectional simultaneous power conversion of dc/dc and dc/ac system. The topology allows the connection of a low voltage battery that acts as a buffer in the standalone system. Simulation results show the efficacy of the multiport bidirectional converter to manage the power flow between PV- Battery connected to three-phase ac load system. © 2022 IEEE.Item Syntheses, quantum mechanical modeling, biomolecular interaction and in vitro anticancer – Tubulin activity of thiosemicarbazones(Academic Press Inc. apjcs@harcourt.com, 2020) Xavier, J.S.; Karthikeyan, K.; Ragavendran, V.; NityanandaShetty, A.A new series of thiosemicarbazones were designed and synthesized. Their structures were confirmed by spectral characterization and single crystal XRD studies. Compounds MTSC-2 and ETSC-3 crystallized in the orthorhombic crystal system with space group Pbc21 andPca21respectively. Density functional theory computational studies were performed on MTSC-2 and ETSC-3 along with natural bond orbital analysis and Mulliken population analysis to study the structural and electronic properties of the thiosemicarbazones. The HOMOs of the two thiosemicarbazones are ?5.2943 and ?5.1133 eV respectively while the LUMOs are ?1.6879 and ?1.6398 eV respectively. The energy gap is 3.6064 and 3.4736 eV respectively. Molecular docking studies were performed to determine the binding mode of the thiosemicarbazones against ?-tubulin. The theoretical studies were further supplemented with tubulin polymerization inhibition assay. All the four thiosemicarbazones proved effective in inhibiting the polymerization of ?- and ?-tubulin heterodimers into microtubules. The anticancer activity of these compounds showed their extreme potency against A549 and HepG2 cancer cell lines with IC50 values of 0.051 – 0.189 µm and 0.042 – 0.136 µm respectively. Compound PTSC-4 showed the highest activity both against tubulin and the two cancer cell lines. This was in correlation with the theoretical studies. Hence, these four compounds, specifically PTSC-4, can be considered to be potential leads in the development of non-metallic anticancer agents. © 2020 Elsevier Inc.Item An Efficient Pseudo-Derivative-Feedback-Based Voltage Controller for DVR Under Distorted Grid Conditions(Institute of Electrical and Electronics Engineers Inc., 2021) Krishna, D.G.A.; Karthikeyan, K.; Koothu Kesavan, K.K.; Kumar, S.Grid integration of distributed energy resources has become a technical challenge in the distribution network operation due to the intermittent nature of renewable energy sources and their impact on grid voltage stability. Thus, a dynamic voltage restorer (DVR) is installed in the distribution network system to reduce such grid voltage impact on sensitive loads. In this article, a pseudo-derivative-feedback (PDF)-based voltage controller is implemented for the effective operation of DVR under voltage disturbances. Response of DVR primarily depends upon its controller action. This article addresses the issues in conventional P and PI multiloop controller with and without feedforward path then proposes PDF control strategy for DVR. Using the proposed controller, dynamic performance of DVR is improved. The efficacy of the proposed controller is illustrated by a comparative study with conventional P and PI controller using time response and relative stability analysis. Finally, PSCAD simulation studies for a 10 kV medium voltage DVR and experimental results using a low voltage laboratory prototype DVR are presented to prove the robustness of proposed controller for DVR under symmetric and asymmetric voltage sags. © 2020 IEEE.Item Virtual and experimental high throughput screening of substituted hydrazones on ?-Tubulin polymerization(Academic Press Inc., 2021) Xavier, J.S.; Karthikeyan, K.; Ragavendran, V.; Manoharan, M.T.; Nityananda Shetty, A.Microtubule targeting agents that disrupt the dynamic functioning of the mitotic spindle are some of the best chemotherapeutic agents. Interruption of microtubule dynamics through polymerization or depolymerization causes cell arrest leading to apoptosis. We report a novel class of aroylhydrazones with anticancer properties. Tubulin inhibition studies were performed using both computational and biological methods. Docking and pharmacophore mapping showed efficient binding between the ligands and the protein. Tubulin inhibition assay showed the aroylhydrazones to be inhibitors of tubulin polymerization. DFT studies explains the geometrical and electronic properties of the compounds. Furthermore, anticancer studies using lung and liver cancer cell lines gave low IC50 values with the methyl substituted hydrazone MH-2 being the most potent. (IC50 of 0.0896 and 0.1040 µM respectively). The methyl group is responsible for the effective binding to the protein. Thus, a new class of tubulin binding agents have been identified as potential agents in cancer therapy. © 2021 Elsevier Inc.Item Enhancing Smart City Connectivity: Implementing Channel-Adaptive Strategies for FSO-Based Drone-Assisted Mobile Access Networks in Urban Environments(Institute of Electrical and Electronics Engineers Inc., 2025) Aarthi, G.; Bhargava Kumar, L.; Vaidya, M.; Nema, S.; Krishnan, P.; Sangeetha, A.; Natarajan, R.; Karthikeyan, K.The global surge in urbanization has catalyzed the evolution of smart city infrastructures, characterized by expansive interconnected networks spanning vast urban landscapes. To address the connectivity challenges inherent in smart city environments, this study advocates for the utilization of autonomous aerial vehicles (AAVs) as an alternative to traditional mobile air base stations. Leveraging Free-Space Optical (FSO) links for downlink transmission from AAVs to users, the proposed system confronts atmospheric turbulence and pointing loss impairments. In this context, the study explores the average spectral efficiency (ASE) performance of the proposed FSO-based Drone-Assisted system employing various channel adaptive techniques, including Optimal Rate Adaptation, Channel Inversion with Fixed Rate, Optimal Power and Rate Adaptation, and Truncated Channel Inversion with Fixed Rate. Additionally, the investigation underscores the impact of factors such as link range, coverage distance, AAV orientation fluctuation standard deviation, AAV position vibration standard deviation, and beam divergence on system performance. By elucidating these aspects, the research aims to contribute valuable insights into the optimization of smart city connectivity, paving the way for enhanced communication infrastructure in urban environments. Notably, the study achieved a maximum ASE of 101 bits/s/Hz using the TIFR adaptation scheme, underscoring the efficacy of the proposed approach. © 2013 IEEE.Item Cyclic back shift method for maximizing PV array power under partial shading(Springer Science and Business Media Deutschland GmbH, 2025) Ramesh, D.; Karthikeyan, K.Partial shading leads to reduction in power output and efficiency of photovoltaic (PV) systems. The physical arrangement of PV modules without changing electrical circuitry plays vital role in reducing the effects caused by partial shading. This paper presents a cyclic back shift (CBS) method to enhance the PV power under partial shading conditions (PSCs). In this method, relocation of modules is based on row positions of modules in a particular column. The proposed CBS method is cost-effective, simple and applicable for both square and non-square array. The proposed CBS method is implemented on 9×9 PV array and tested in both software (20.25 kW system) and hardware (0.81 kW system) environments under various shading patterns. The performance parameters such as fill factor (FF), mismatch loss (ML) and efficiency (?) are plotted. Further, a comparative analysis is carried between the proposed CBS method, total cross tied (TCT) and different existing reconfiguration schemes. From the experimental results, it is observed that the proposed CBS method is able to enhance the GMPP by minimum 11.83% under shading pattern-II and maximum of 18.78 under shading pattern-III compared to TCT configuration. Hence, the CBS method of module arrangement is an effective solution in reducing the partial shading effects. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2024.Item Enhanced Power Management in Multiport Converter with SRF-PI Control and SVPWM for PV-Battery Standalone Systems(Springer, 2025) Gangashetty, P.A.; Karthikeyan, K.This paper presents a novel single-stage three-port power converter topology for standalone renewable energy systems that integrate photovoltaic (PV) generation and battery energy storage to supply a three-phase AC load. The proposed converter architecture combines a multi-phase bidirectional interleaved direct current-to-direct current (DC/DC) converter with a full-bridge inverter, forming a compact and modular power interface that reduces the number of conversion stages and minimizes component count and volume. A synchronous reference frame-based proportional–integral (SRF-PI) controller is employed for decoupled regulation of the DC-link and AC output voltages, while Space Vector Pulse Width Modulation (SVPWM) ensures fixed-frequency switching and optimal DC bus utilization. The control strategy enables effective power flow management between the PV, battery, and load under dynamic irradiance and load variations. Real-time implementation on an FPGA-based platform validates the feasibility and performance of the proposed control method, with a 300 W experimental prototype demonstrating practical applicability. The system is also modeled and simulated in MATLAB/Simulink to evaluate transient and steady-state behavior under different operating conditions. A comparative analysis with the Finite Control Set Model Predictive Control (FCS-MPC) technique highlights that the SRF-PI controller offers improved lower transient overshoot, reduced steady-state error, and superior power quality while significantly reducing the computational burden and implementation complexity. The proposed system offers a scalable, efficient, and hardware-friendly solution suitable for standalone PV-battery-based microgrids and rural electrification applications. © The Author(s), under exclusive licence to Springer Nature Singapore Pte Ltd. 2025.