Faculty Publications

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Author: search.filters.author.Kulkarni, S.M.Subject: search.filters.subject.Adhesives

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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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    An experimental study on adhesion, flexibility, interlaminar shear strength, and damage mechanism of jute/rubber-based flexible “green” composite
    (SAGE Publications Ltd, 2022) Mahesh, V.; Joladarashi, S.; Kulkarni, S.M.
    Determining the interlaminar shear strength (ILSS) of the composite laminates is vital for deciding their usage in any engineering applications. The matrix used and its curing characteristics are vital in deciding the ILSS of the composite. Present work deals with an experimental study on adhesive behavior, degree of flexibility, ILSS, and damage mechanism of the novel jute/rubber-based flexible “green” composite. The proposed flexible composites were prepared in three different stacking sequences, namely jute/rubber/jute (JRJ), jute/rubber/rubber/jute (JRRJ), and jute/rubber/jute/rubber/jute (JRJRJ), using compression molding technique. After determining the optimal curing characteristics of the proposed rubber-based matrix, the constituents are tested for their adhesive strength with the matrix which showed that rubber matrix system is compatible with jute fabric and natural rubber sheet. Composites are prepared and degree of flexibility for each stacking sequence is found out. Results pertaining to ILSS show that JRJRJ has better ILSS compared to JRJ and JRRJ. Fractographic analysis using scanning electron microscope reveals the mode of failure of the composites and the mechanism governing their failure. Fourier transform infrared spectroscopic study reveals the bonding between the constituents is good enough to be used in composites with flexibility. © The Author(s) 2019.