Faculty Publications
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Item Biocompatible Nanohydroxyapatite from Cuttlefish Bone by Mechanochemical Method for Bone Tissue Engineering Applications(Springer, 2024) Jalageri, M.B.; Kumar, G.C.Hydroxyapatite was synthesized from coral cuttlebone using a mechanochemical method in this study. The synthesized material was characterized using various techniques to determine its phases and functional groups. Field emission scanning electron microscope (FESEM), Fourier transform infrared spectroscopy (FTIR), and thermogravimetric analysis TGA were employed. FESEM analysis revealed an onedimensional nanorod morphology of the developed material. X-ray diffraction (XRD) confirmed that the primary phase was hydroxyapatite, with slight traces of tricalcium phosphate detected after calcination at 800 °C. The FTIR spectra exhibited peaks corresponding to phosphate and hydroxyl groups. At the same time, TGA results indicated the absence of any organic phase. Furthermore, the synthesized hydroxyapatite displayed excellent antimicrobial activity against Escherichia coli and Staphylococcus aureus bacteria. Cytocompatibility tests with MG63 fibroblast cells demonstrated that these materials are both antimicrobial and biocompatible, making them suitable for various biomedical applications. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Dynamic Mechanical Analysis and Thermal Stability of Neem Wood Veneer Plastic Composites(Elsevier Ltd, 2019) Nagamadhu, M.; Vijay Kumar, S.; Ravi Kumar, S.; Suraj, R.; Kumar, G.C.The neem wood veneer is used as core materials in many of the wood structural applications. In this research work, neem wood polymer composite (NWPC) were prepared to understand the effect of weight fraction, stacking sequence, and interfacial bonding between neem wood veneer and epoxy material. NWPC were prepared conventional compression molding and Thermo-mechanical properties of wood epoxy composite samples were investigated by the dynamic mechanical analyzer over the temperature range from 30 to 180°C. Storage modulus (G') and Loss modulus (G") of NWPC samples exhibited significant effect with respect weight fraction of wood veneer. Similarly epoxy has good interfacial bonding agent to enhance the strength of multilayered wood polymer composites. However, the stacking sequence having major changes in dynamic mechanical properties, G' & G" increases along the wood fiber direction with negligible load bearing capacity in transfers direction. By changing the orientation of the wood veneer properties improved in both the direction. Additionally, scanning electron microscopy (SEM) evidently shows the interfacial bonding efficiency. © 2019 Elsevier Ltd.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 Influence of extender on Thermo-mechanical Properties of melamine-urea-formaldehyde [MUF] for wood adhesive applications(Elsevier Ltd, 2019) Nagamadhu, M.; Ravi Kumar, S.; Suraj, R.; Manjunath Iyer, K.B.; Kumar, G.C.Now a day's many researchers are trying to build alternative materials for raw wood, by using wood composite materials as an alternative. However, in wood polymer composites major limitations on adhesive materials and its bonding strength effect with economy. In this paper melamine-urea-formaldehyde (MUF) wood adhesive properties were determined over a range of temperature. MUF prepared by considering 1:2.3 weight ratio of urea to the formalin, at 90°C and pH is adjusted to 7.5-8.0 and second urea is added at certain time interval to reduce the formaldehyde emission. MUF has certain properties like flow time, viscosity, solid content, water tolerance, shelf life which is calculated by the observation made. The cost of MUF adhesive can be controlled by adding extender (Maida). As wood polymer composites subjected to over a range of temperature. It's necessary to understand the thermo-mechanical properties of MUF reinforced with Maida as an extender using Dynamic Mechanical Analyzer (DMA). The DMA gives in-phase component like storage modulus, loss modules and tan delta. The results show that storage modulus increases with adding extender even at higher temperature, these shows that by adding extender MUF resist the intermolecular motion. The damping factors were found to be increases by adding extender. Tan delta of MUF exhibiting narrow peak with higher magnitude indicates more energy dissipates, by adding the extender it reduces. The adding extender Maida (MD) water absorption decreases, this shows better MUF having better bonding with extender. © 2019 Elsevier Ltd.Item Finite Element Analysis for Material Optimization of a Spur Gear by Radial Holes(Springer Science and Business Media Deutschland GmbH, 2022) Sutar, S.; Kumar, G.C.; Doddamani, M.Use of advanced materials in gear manufacturing lead to the best use of the material is achieved by geometric optimization, which uses less material. Removal of the material from gear makes lighter weight gear, and the simulation study helps in understanding their effects on stress distribution. This present research work focuses on removing material from the gear tooth for developing lightweight gears. Circular holes are introduced radially through the gear tooth and holes of 1.5 mm diameter created from top land of the gear tooth with varying depth from 5 to 20 mm. This leads to a volume reduction of 2.49% to a maximum of 12.451% as compared to no radial hole on gear. The analysis of CAD models created in CREO software of pinion and gear assembly is carried out in Ansys Workbench 17.2. Stresses in gear proposed are compared with the gear without a hole. The magnitude of stresses at the roots for both pinion and gear is observed and discussed. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Comparison of Stress Distribution of Graphene-Based Bioactive Material for Zirconia and Titanium by Applying Orthotropic Properties: A Finite Element Analysis(Springer Science and Business Media Deutschland GmbH, 2024) Singh, R.K.; Verma, K.; Kumar, G.C.This study employs finite element analysis to examine stress distribution at the bone–implant interface in graphene-based dental implants. Four implant models, encompassing titanium and zirconia with and without graphene coating, are assessed under axial and oblique loading. Considering their anisotropic nature, bone tissues are simulated as orthotropic, while implants are treated as homogeneous and isotropic. The study utilizes one-way ANOVA and Kruskal–Wallis tests for statistical analysis to compare stress distribution among implant groups. Results indicate superior von Mises stress distribution in graphene-based implants (A2 and A4) compared to the pure material group. The incorporation of graphene coating significantly reduces implant stresses under axial and oblique loads compared to titanium and zirconia. In conclusion, the study underscores the potential benefits of graphene-based implant models in optimizing stress distribution at the bone–implant interface, emphasizing the importance of suitable implant models and biomaterial selection for enhanced dental implant performance. © The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd. 2024.Item Potential of Graphene-Functionalized Polymer Surfaces for Dental Applications: A Systematic review(Taylor and Francis Ltd., 2025) Singh, R.K.; Verma, K.; Kumar, G.C.; Jalageri, M.B.Graphene, a two-dimensional carbon nanomaterial, has garnered widespread attention across various fields due to its outstanding properties. In dental implantology, researchers are exploring the use of graphene-functionalized polymer surfaces to enhance both the osseointegration process and the long-term success of dental implants. This review consolidates evidence from in-vivo and in-vitro studies, highlighting graphene’s capacity to improve bone-to-implant contact, exhibit antibacterial properties, and enhance mechanical strength. This research investigates the effects of incorporating graphene derivatives into polymer materials on tissue response and compatibility. Among 123 search results, 14 articles meeting the predefined criteria were analyzed. The study primarily focuses on assessing the impact of GO and rGO on cellular function and stability in implants. Results indicate promising improvements in cellular function and stability with the use of GO-coated or composited implants. However, it is noted that interactions between Graphene derivatives and polymers may alter the inherent properties of the materials. Therefore, further rigorous research is deemed imperative to fully elucidate their potential in human applications. Such comprehensive understanding is essential for unlocking the extensive benefits associated with the utilization of Graphene derivatives in biomedical contexts. © 2024 Informa UK Limited, trading as Taylor & Francis Group.Item Dynamic study of composite material shaft in high-speed rotor-bearing systems(Inderscience Publishers, 2019) Gonsalves, T.H.; Kumar, G.C.; Ramesh, M.R.In this work the composite material shaft in high-speed rotor-bearing systems is analysed to achieve better rotor dynamics along with the effect of internal damping of the composite shaft. The pioneering studies on rotating composite shaft and internal damping are revisited to evaluate its effects on rotor dynamics of high-speed rotor-bearing systems. Two practical rotor-bearing systems are selected to study their suitability for composite shaft application where the composite material is used in the cold section while the existing steel alloy is retained in the hot section as well as at the ends. The rotor dynamic analysis shows significant improvements in rotor dynamics of one of the rotor-bearing systems where the first lateral mode changes to desirable rigid mode from flexure mode shape of existing metallic shaft rotor-bearing system. The frequency values of second and third modes also increase above the operating speed indicating a clear advantage in rotor dynamics. © © 2019 Inderscience Enterprises Ltd.Item Hydroxyapatite Reinforced Polyvinyl Alcohol/Polyvinyl Pyrrolidone Based Hydrogel for Cartilage Replacement(MDPI, 2022) Jalageri, M.B.; Kumar, G.C.Polyvinyl alcohol (PVA) and Polyvinyl Pyrrolidone (PVP) hydrogels are desirable biomaterials for soft tissue repair and replacement. However, the bio-inertness and poor cell adhesive potency of the PVA and PVP hinder the wide range of biomedical applications. In the present work, PVA and PVP were blended with a one-dimensional hydroxyapatite nanorod (HNr), and PVA/PVP/HNr composite hydrogel was synthesized by the freeze-thaw process. The developed hydrogels were characterized by Scanning Electron Microscope (SEM). The bio-ceramic nanohydroxyapatite content was optimized, and it was found that reinforcement improves mechanical strength as well as bioactivity. The compression strength values are 2.47 ± 0.73 MPa for the composite having 2 wt% of nanohydroxyapatite. The storage modulus was much higher than the loss modulus, which signifies the elastic dominancy similar to cartilage. Besides, the antimicrobial activity of nanohydroxyapatite reinforced PVA hydrogel towards bacterial species, Escherichia coli (E. Coli), Staphylococcus aureus (S. aureus) was satisfactory, and the in vitro biocompatibility response towards Human Mesenchymal stem cells(hMSC) after 72 h of culture confirms nanohydroxyapatite reinforced PVA/PVP hydrogels are the promising alternatives for next-generation cartilage substitutes. © 2022 by the authors.Item Study on tearing strength of woven sisal fabrics for tents and polymer composite applications(Taylor and Francis Ltd., 2023) Nagamadhu, M.; Kivade, S.B.; Jeyaraj, J.; Kumar, G.C.; Shivaraj, B.W.; Bharath, K.N.The use of plant fibers as a reinforcement in composites has increased daily owing to their favorable environmental considerations. Fabric properties play a significant role in alignment during composites processing, enhancing the composite properties. However, the fabric structures are formed by warp and weft yarns. These yarns are subjected to axial and shear loads, respectively. However, very limited work has been carried out on the study involving the tearing strength of the fabric. So it is necessary to study the effect of the tearing load of fabrics before converting them into composites. This paper focuses on the tearing strength of the sisal woven fabrics in both warp and weft directions. Two plain and one weftrib fabrics are prepared using sisal fibers, and their physical properties were characterized as per textile testing standards. Tear strength has been determined by Elmendorf Tear and Single Rip Tear Method by varying crosshead speeds. The result shows that woven patterns and number yarns significantly impact tearing strength. In the case of the weft rib pattern, the warp direction exhibits the highest tearing strength compared to the weft direction. Also, in the case of weftrib fabrics, the weft direction indicates better-tearing strength than another woven pattern. © 2023 The Author(s). Published with license by Taylor & Francis Group, LLC.