Faculty Publications

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Author: search.filters.author.Karanth P, N.

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    Advances in micro electro discharge machining of biomaterials: a review on processes, industrial applications, and current challenges
    (Taylor and Francis Ltd., 2024) Korgal, A.; Shettigar, A.K.; Karanth P, N.; Prabhakar, D.A.P.
    Micro Electro-Discharge Machining is a precision machining process that uses electrical discharge to produce small-scale components with high accuracy. A metal workpiece is machined in this process by repeatedly generating spark between a tool electrode and the workpiece, removing material in a controlled manner. The significance of µ-EDM lies in its ability to produce highly accurate and complex components with a high surface finish, making it ideal for use in various industries, including aerospace, medical, and electronics. The critical parameters to the success of µ-EDM include the electrical discharge energy, voltage, current, pulse duration, and spark gap between the tool electrode and workpiece, including the shape and size of the tool electrode. This review article discusses the µ-EDM process used to machine biological materials and also examines the µ-EDM, dry µ-EDM procedure, and the features of biomedical materials for biocompatibility, 3D micro shape machining with tool wear composition, and thin film coating for microelectrodes. The impact of introducing nanoparticles to dielectric fluids is further clarified in this article. This study addresses the prospective future research subjects and application areas for the µ-EDM process in order to fulfill the demanding criteria for biomaterials and their usage in the production of bioimplants. © 2024 Taylor & Francis Group, LLC.
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    Investigations on the thermal actuation of carbon black reinforced pdms composite uni-layer and bi-layer cantilever beams
    (ModTech Publishing House office@hotelfloramamaia.ro, 2020) Hiremath, H.; Desai, S.; Kulkarni, S.M.; Karanth P, N.; Desai, V.
    Actuators are the essential components of robots, switches, relays, and many other automatic systems. There are various actuator types based on material, geometry, and stimulus. Nowadays, polymer composite based actuators are gaining importance due to their flexibility, ease of processing, low cost, and easy way of tailoring the properties. Among the polymers, Polydimethylsiloxane (PDMS) is one of the promising polymers for the actuator. In the present study, unilayer and bilayer cantilever beams of PDMS based composite subjected to a thermal stimulus are investigated. The Finite Element (FE) and the analytical models are developed for unilayer and bilayer polymer composite beams and simulated for actuator response. The deflection behavior of these beams is investigated for a temperature input range of 308K to 368K. The beams are analyzed for varying Carbon Black(CB) content from 5 to 25 Vol% in PDMS polymer and beam thickness from 1mm to 5mm. It is observed that with an increasing percentage of filler content, the increment in deflection of the bilayer beam is appreciably higher when compared to the unilayer beam. For 25 Vol% of CB, the bilayer beam shows 11.48 times improvement in deflection value. Also, it is noticed that the thickness of the beams influences deflection more compared to the percentage of the CB content. The deflection of the unilayer and bilayer beam is observed to increase linearly with temperature input. At 368K, the bilayer beam deflection is 6.87 times greater than the unilayer. Hence this analysis is the baseline for predicting the actuator performance of the unilayer and bilayer polymer composite beams considering the set of variables. © International Journal of Modern Manufacturing Technologies.
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    Performance analysis of valveless micropump with disposable chamber actuated through Amplified Piezo Actuator (APA) for biomedical application
    (Elsevier Ltd, 2020) Mohith, M.; Karanth P, N.; Kulkarni, S.M.
    The precise manipulation of fluid through pumping systems has been the technological challenge in microfluidic applications. The biomedical applications call for precise and accurate delivery of fluid through miniaturized pumping systems. This paper presents a novel valveless micropump for biomedical applications operated by the Amplified Piezo Actuator. Integrating the disposable chamber and reusable actuator with the proposed micropump allows the actuator to be reused and eliminates the possibility of infection or contagion. The micropump was fabricated using low-cost polymeric materials like Polymethylmethacrylate (PMMA), Silicone rubber through CNC milling, Laser Cutting, conventional moulding operation. The micropump chamber, nozzle/diffusers, and a bossed diaphragm constituted disposable part and Amplified Piezo Actuator with structural support formed the reusable part of the micropump. The bossed diaphragm of the pump chamber consists of a central cylindrical protrusion to reduce the force of adhesion on the diaphragm and transmit force required for micropump actuation. A theoretical analysis was performed to assess the effect of diaphragm thickness and the bossed region on the effective stiffness of the diaphragm, which in turn influences the deflection achieved. Besides, an analytical approach has been presented to address the effect of adhesive force on the diaphragm surface due to the residual fluid and chamber depth. The experimental characterization of the micropump was carried out to determine the optimal performance parameters with water, fluids mimicking blood plasma, and whole blood. Based on the experimental results, the pumping rate and head developed by the micropump have been significantly affected by factors such as bossed ratio, diaphragm thickness, depth of the micropump chamber, and viscosity of the fluid. The optimum configuration of the micropump cosidered silicone rubber diaphragm with thickness of 0.20 mm having a bossed ratio of 0.33 and a chamber depth of 1.25 mm. With the optimal operating parameters of 150 V sinusoidal input of frequency 5 Hz, the proposed micropump was capable of delivering 7.192 ml/min, 6.108 ml/min, and 5.013 ml/min of water and blood plasma, whole blood mimicking fluid with the maximum backpressure of 294.00 Pa, 226.243 Pa, and 204.048 Pa respectively. The corresponding resolution, i.e., pumping volume/stroke of the micropump was about 23.972 µl, 20.358 µl, and 16.708 µl, respectively. © 2020 Elsevier Ltd
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    Performance comparison of piezo actuated valveless micropump with central excitation and annular excitation for biomedical applications
    (IOP Publishing Ltd, 2021) Mohith, S.; Karanth P, N.; Kulkarni, S.M.; Desai, V.; Patil, S.S.
    In recent years, microfluidic devices, particularly micropumps, are extensively utilized in biomedical applications. The micropump used in biomedical applications needs to possess precise delivery of fluids at requires rate and pressure. The present work proposes a valveless mechanical micropump with a disposable chamber integrated with a novel concept of annular excitation of the diaphragm to fulfil the need for precise delivery of fluids in biomedical applications. The proposed design of the micropump involves a reusable configuration of the amplified piezoelectric actuator (APA) for micropump actuation and a disposable pump chamber. The pumping of the fluids occurs through the oscillation of the silicone rubber bossed diaphragm. The performance of a mechanical micropump depends on the oscillation amplitude of the diaphragm. Thus, the conventional approach of central excitation of the bossed diaphragm is replaced by a novel approach of annular excitation intended to enhance the deflection range, thus the volumetric performance of the micropump. An experimental comparative study is carried out to assess the deflection characteristics of central excitation and annular excitation of the bossed diaphragm. The maximum deflection measured with the annularly excited configuration of the bossed diaphragm is about 1953.4 ± 8.00 µm at 150 V, 43.5 Hz, which is superior to the maximum deflection of centrally excited configuration delivering 717.99 ± 4.00 µm at 150 V, 9.5 Hz. Further, the experimental studies aimed to fabricate and characterize the micropump with central and annular excitation approaches. The proposed micropump with central excitation delivered the maximum water flow rate of about 7.192 ± 0.147 ml min-1 and backpressure of 0.294 kPa at 150 V, 5 Hz. However, the enhancement of the deflection characteristics of the bossed diaphragm under annular excitation leads to performance enhancement of the micropump with the flow rate of 95.10 ± 0.444 ml min-1 and backpressure of 1.472 kPa at 150, 30 Hz. © 2021 IOP Publishing Ltd.
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    Design and characterization of a pneumatic muscle actuator with novel end-fittings for medical assistive applications
    (Elsevier B.V., 2021) do Rosario Carvalho, A.D.; Karanth P, N.; Desai, V.
    Pneumatic muscle actuators (PMA) are a class of soft actuators known for their high power to weight ratio and inherent compliance. The pneumatic muscle's inherent properties make them very favorable for assistive applications (e.g., medical exoskeletons). This study presents a novel end-fitting design that makes the developed pneumatic muscle actuator lightweight, cost-effective, and modular, thus simplifying the process of assembly and maintenance. The pneumatic muscle actuator assembled using the novel end fittings achieves a shorter overall length without compromising its contraction. The pneumatic muscle actuator has been assembled using a commercial bladder and a braided sleeve alongside a pair of 3D printed novel end-fittings. The paper also details the developed actuator's characterization for force and deflection parameters at various operating pressures. A total of four muscle actuators of varying diameters with constant actuation length (100 mm) were developed and tested to showcase the effect of size on the muscle actuator's behavior. The study presented here also involved comparing three mathematical models developed for pneumatic muscles in order to find a model which closely resembles the developed muscle actuator. Finally, the developed pneumatic muscle actuator's behavior is compared with a commercially available muscle to determine the efficacy of the developed muscle's design. The tests showed that the muscle using a bladder of smaller volume but higher tensile modulus had a higher accuracy and stable performance. As the muscle is intended for medical applications, it was also put through an endurance test with realistic loading and pressure conditions, which revealed very promising results. © 2021 Elsevier B.V.
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    Development of a Convolutional Neural Network Model to Predict Coronary Artery Disease Based on Single-Lead and Twelve-Lead ECG Signals
    (MDPI, 2022) Vasudeva, S.T.; Rao, S.S.; Karanth P, N.; Shettigar, A.; Mahabala, C.; Kamath, P.; Gowdru Chandrashekarappa, M.; Linul, E.
    Coronary artery disease (CAD) is one of the most common causes of heart ailments; many patients with CAD do not exhibit initial symptoms. An electrocardiogram (ECG) is a diagnostic tool widely used to capture the abnormal activity of the heart and help with diagnoses. Assessing ECG signals may be challenging and time-consuming. Identifying abnormal ECG morphologies, especially in low amplitude curves, may be prone to error. Hence, a system that can automatically detect and assess the ECG and treadmill test ECG (TMT-ECG) signals will be helpful to the medical industry in detecting CAD. In the present work, we developed an intelligent system that can predict CAD, based on ECG and TMT signals more accurately than any other system developed thus far. The distinct convolutional neural network (CNN) architecture deals with single-lead and multi-lead (12-lead) ECG and TMT-ECG data effectively. While most artificial intelligence-based systems rely on the universal dataset, the current work used clinical lab data collected from a renowned hospital in the neighborhood. ECG and TMT-ECG graphs of normal and CAD patients were collected in the form of scanned reports. One-dimensional ECG data with all possible features were extracted from the scanned report with the help of a modified image processing method. This feature extraction procedure was integrated with the optimized architecture of the CNN model leading to a novel prediction system for CAD. The automated computer-assisted system helps in the detection and medication of CAD with a high prediction accuracy of 99%. © 2022 by the authors.
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    Characterization of pneumatic muscle actuators and their implementation on an elbow exoskeleton with a novel hinge design
    (Elsevier B.V., 2022) do Rosario Carvalho, A.D.D.R.; Karanth P, N.; Desai, V.
    The exoskeleton plays an essential role in the field of physical rehabilitation. Several actuators are used for the exoskeleton application, but the pneumatic muscle actuator has proved to be the best due to its high power to weight ratio, compliance, and safe operation. The objective of this paper involves the fabrication and experimental characterization of a pneumatic muscle actuator to actuate an exoskeleton for the elbow joint. This paper presents the development and testing of twelve pneumatic muscles of varying materials and sizes, to find the best combination to suit the intended application. The characterization process involved several tests, which related force, deflection, and pressure at various loading conditions. A modular test rig was developed to conduct all the tests with minor adjustments to the test setup. The study also involved designing and developing an elbow exoskeleton to test the pneumatic muscle in the real-world scenario. The exoskeleton is designed with a novel hinge to compensate for the antagonistic nature of the pneumatic muscle actuator. The tests showed the muscles with higher tensile modules bladders having a lower hysteresis and better load handling capability, but these suffered from lower contraction and force characteristics. The styrene-based muscle with a 12mm bladder (S12LB) showed the best force and deflection characteristics at various pressures and loading conditions. The styrene bladder has a modulus closer to the skeletal muscle, therefore demonstrating higher compliance and making it a preferred choice for the exoskeleton application © 2022