Faculty Publications

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Publications by NITK Faculty

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    A new strategy to refine crude Indian sardine oil
    (Japan Oil Chemists Society yukagaku@jocs-office.or.jp, 2017) Charanyaa, S.; Belur, B.D.; Iyyaswami, R.
    Current work aims to develop a refining process for removing phospholipids, free fatty acids (FFA), and metal ions without affecting n-3 polyunsaturated fatty acid (n-3 PUFA) esters present in the crude Indian sardine oil. Sardine oil was subjected to degumming with various acids (orthophosphoric acid, acetic acid, and lactic acid), conventional and membrane assisted deacidification using various solvents (methanol, ethanol, propanol and butanol) and bleaching with bleaching agents (GAC, activated earth and bentonite) and all the process parameters were further optimized. Degumming with 5%(w/w) ortho phosphoric acid, two stage solvent extraction with methanol at 1:1 (w/w) in each stage and bleaching with 3% (w/w) activated charcoal loading, at 80ºC for 10 minutes resulted in the reduction of phospholipid content to 5.66 ppm from 612.66 ppm, FFA to 0.56% from 5.64% with the complete removal of iron and mercury. Under these conditions, the obtained bleached oil showed an enhancement of n-3 PUFA from 16.39% (11.19 Eicosapentaenoic acid (EPA) + 5.20 Docosahexaenoic acid (DHA)) to 17.91% (11.81 EPA + 6.1 DHA). Replacing conventional solvent extraction with membrane deacidification using microporous, hydrophobic polytetrafluoroethylene membrane (PTFE), resulted in a lesser solvent residue (0.25% (w/w)) in the deacidified oil. In view of lack of reports on refining of n-3 PUFA rich marine oils without concomitant loss of n-3 PUFA, this report is significant. © 2017 by Japan Oil Chemists’ Society.
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    Comparative evaluation of organic contamination sources from roller and pencil type PVA brushes during the Post-CMP cleaning process
    (Elsevier Ltd, 2020) Lee, J.-H.; Poddar, M.K.; Han, K.-M.; Ryu, H.-Y.; Yerriboina, N.P.; Kim, T.-G.; Wada, Y.; Hamada, S.; Hiyama, H.; Park, J.-G.
    In post-CMP (chemical mechanical polishing) processing, the use of poly vinyl acetal (PVA) brushes to clean the wafer surface is one of the most effective and prominent techniques applied for the removal of CMP contaminants. Recently, organic contaminants induced in different types of PVA brushes during brush manufacturing have been drawing substantial research interest in CMP communities. In this study, investigated the root cause of these residual organic impurities in two different types of PVA brushes was investigated: roller and pencil type brushes. PVA roller brushes have a skin layer due to the brush molding process, but pencil-type PVA brushes do not have the skin layer. Extraction of organic impurities from both types of brushes was accomplished using an ultrasound-assisted technique at a sonication frequency of 40 kHz, and input power of 600 W. Further evaluation of these organic impurities using Field Emission Scanning Electron Microscopy (FE-SEM) revealed a large number of organic impurities in roller brushes and negligible impurities in pencil brushes. Time of flight secondary ion mass spectrometry (TOF-SIMS) analysis confirmed polydimethylsiloxane (PDMS) as the organic impurities extracted from PVA roller brushes, which were generated during the brush manufacturing process. The PDMS content in PVA roller brushes was further analyzed using FE-SEM micrographs via dissolving the organic impurities in tetramethylammonium hydroxide solution (TMAH). During brush fabrication, the high content of PDMS organic impurities in roller PVA brushes is essentially attributed to the presence of the additional skin layer formed by the mold releasing agent at the mold-cavity interface. © 2020 Elsevier Ltd
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    Isolation of microcrystalline cellulose from Musa paradisiaca (banana) plant leaves: physicochemical, thermal, morphological, and mechanical characterization for lightweight polymer composite applications
    (Springer Science and Business Media B.V., 2024) Indra Reddy, M.I.; Sethuramalingam, P.; Sahu, R.K.
    Natural cellulose owing to its remarkable microstructural and physiochemical behaviour, and its eco-friendliness have attracted significant interest among the researchers. Therefore, in this work, microcrystalline cellulose (MCC) is extracted from the Musa paradisiaca plant leaf (MPPL) debris which is accumulated in large quantity and treated as waste material. The purified micro-cellulose is obtained by subjecting the MPPL raw material to alkali treatment followed by acid hydrolysis, bleaching and slow pyrolysis. From the FT-IR spectra of the cleaned cellulose, it is observed that its amorphous phase is eliminated. The crystallinity index is found to be 87.42% and this value is attributed to the sodium chlorite bleaching. The particle size analyzer results show that the micro-cellulose found to have a bimodal distribution with an average size of 35.97 μm and standard deviation 16.53. It is evident from SEM that the microcrystalline cellulose is of semi-spherical in shape and found to be aggregated with uneven distribution. Further, TGA analysis is carried out in this work and the results show that the microcrystalline cellulose can exhibit high heat resistance up to 297 °C. Surface roughness values (Ra) for MPPL MCC is 58.41 μm. The properties are well suited for futuristic polymer composite applications such as filler addition in biofilm for packaging industries and coating material in pharma industries. © The Polymer Society, Taipei 2024.
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    Comprehensive Characterization of Novel Jute Fabrics with Musa Paradisiaca Leaf Agro-Waste Based Micro Cellulosic Fillers Reinforced Epoxy Composites For Lightweight Applications
    (Korean Fiber Society, 2025) Indra Reddy, M.I.; Sethuramalingam, P.; Sahu, R.K.
    For lightweight, sustainable, high-strength products, hybrid bio-epoxy composites materials were the most excellent choice for the production industry. The investigation proceeds in developing a four-stacked sequence jute-woven mats reinforced with epoxy composite and added with micro-cellulose fillers. The extraction of micro cellulose from Musa paradisiaca plant leaf (MPPL) was carried out through a series of processes, including alkali treatment, acid hydrolysis, bleaching, and slow pyrolysis. The composite was fabricated using the conventional hand lay-up method and compression molding. The microcellulose was added to the stacked composite at varying weight percentages (0, 2.5, 5, 7.5, and 10%). Thermo-mechanical and water intake characterization were investigated using ASTM. The findings revealed that incorporating 5% MPPL cellulose into the jute-stacked layer sequence resulted in improved hardness (95 HRRW), tensile modulus (3407.69 MPa), tensile strength (79.74 MPa), flexural modulus (2195.752 MPa), flexural strength (56.87 MPa), and crystallinity index (72.7%). However, a reduction in impact strength (23.27 kJ/m2) was noted compared to the unfilled composite. The higher thermal degradation (480 °C) behavior of the filler-reinforced composite makes them a suitable material for applications in high-temperature environments. Fractographical morphology was also investigated to reveal the bonding behavior, voids formations, agglomeration of fillers, and fracture behavior. Thus, this distinguishable composite characterization will aid the manufacturing industries in producing high-strength biodegradable materials. © The Author(s), under exclusive licence to the Korean Fiber Society 2025.
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    Impact of sulfate supplement on bioleaching of iron from fly ash residue using isolated Acidithiobacillus ferrooxidans strain: A Box-Behnken process optimisation
    (Korean Society of Environmental Engineers, 2025) Bhaskar, S.; Apoorva, K.V.; Ashraf, S.; Shruthi, R.; Manoj, A.
    Fly ash, a residue from coal combustion contains significant iron content (10-40%), has potential applications in various fields. Present study investigated the impact of sulfate on bioleaching of iron from fly ash, using a novel Acidithiobacillus ferrooxidans strain. Iron dissolution obtained was 95.5 mg/L with 100 rpm shake flask speed, 3% pulp density, pH 3.0, and 5.5 g/L sulphate supplement, compared to 74.5 mg/L without sulphate over 15 days. The study employed Box-Behnken design for Design of Experiments. Variables ranged from 50 rpm – 150 rpm for shake flask speed, 2.5 – 3.5 for pH, 1% – 5% for pulp density, and 1.0 g/L – 10 g/L for sulfate concentration. In the experiment with sulfate supplement, the concentration of sulfate was treated as a variable parameter, as opposed to the pulp density, while taking into account other relevant characteristics. Iron dissolution was taken as a response. Pulp density and sulfate concentration significantly affected iron dissolution. A quadratic regression model was fit and an ANOVA was performed. According to the model, sulfate concentration has a positive linear influence with sulfate supplement, while for no sulfate supplement, shake flask speed and pulp density have a positive effect on the bioleaching of iron from fly ash. © 2025 Korean Society of Environmental Engineers.