Faculty Publications
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Item Evaluation of water quality index for drinking purposes for river Netravathi, Mangalore, South India(2008) Avvannavar, S.M.; Shrihari, S.An attempt has been made to develop water quality index (WQI), using six water quality parameters Dissolved oxygen (DO), Biochemical oxygen Demand (BOD), Most Probable Number (MPN), Turbidity, Total Dissolved Solids (TDS) and pH measured at eight different stations along the river basin. Rating curves were drawn based on the tolerance limits of inland waters and health point of view. Bhargava WQI method and Harmonic Mean WQI method were used to find overall WQI along the stretch of the river basin. Five point rating scale was used to classify water quality in each of the study areas. It was found that the water quality of Netravathi varied from Excellent to Marginal range by Bhargava WQI method and Excellent to Poor range by Harmonic Mean WQI method. It was observed that the impact of human activity was severe on most of the parameters. The MPN values exceeded the tolerable limits at almost all the stations. It was observed that the main cause of deterioration in water quality was due to the lack of proper sanitation, unprotected river sites and high anthropogenic activities. © Springer Science+Business Media B.V. 2007.Item Effects of electric potential, NaCl, pH and distance between electrodes on efficiency of electrolysis in landfill leachate treatment(Taylor and Francis Inc. 325 Chestnut St, Suite 800 Philadelphia PA 19106, 2017) Erabee, I.K.; Ahsan, A.; Jose, B.; Arunkumar, T.; Sathyamurthy, R.; Idrus, S.; Daud, N.N.N.This study investigated the effects of different parameters on the removal efficiencies of organic and inorganic pollutants in landfill leachate treatment by electrolysis. Different parameters were considered such as the electric potential (e.g., 24, 40 and 60 V), hydraulic retention time (HRT) (e.g., 40, 60, 80, 100 and 120 min), sodium chloride (NaCl) concentration (e.g., 1, 3, 5 and 7%), pH (e.g., 3, 7 and 9), electrodes materials [e.g., aluminum (Al) and iron (Fe)] and distance between electrodes (e.g., 1, 2 and 3 cm). The best operational condition of electrolysis was then recommended. The electric potential of 60 V with HRT of 120 min at 5% of NaCl solution using Al as anode and Fe as cathode (kept at a distance of 3 cm) was the most efficient condition which increased the removal efficiencies of various parameters such as turbidity, salinity, total suspended solids (TSS), total dissolved solids (TDS), biochemical oxygen demand (BOD), chemical oxygen demand (COD) and heavy metals (e.g., Zn and Mn). The higher removal percentages of many parameters, especially COD (94%) and Mn (93%) indicated that the electrolysis is an efficient technique for multi-pollutants (e.g., organic, inorganic and heavy metals) removal from the landfill leachate. © 2017 Taylor & Francis Group, LLC.Item Customizable ceramic nanocomposites using carbon nanotubes(MDPI AG indexing@mdpi.com Postfach Basel CH-4005, 2019) Okolo, C.; Rafique, R.; Sagar, S.S.; Subhani, T.; Saharudin, M.S.; Badekai Ramachandra, B.R.; Inam, F.A novel tweakable nanocomposite was prepared by spark plasma sintering followed by systematic oxidation of carbon nanotube (CNT) molecules to produce alumina/carbon nanotube nanocomposites with surface porosities. The mechanical properties (flexural strength and fracture toughness), surface area, and electrical conductivities were characterized and compared. The nanocomposites were extensively analyzed by field emission scanning electron microscopy (FE-SEM) for 2D qualitative surface morphological analysis. Adding CNTs in ceramic matrices and then systematically oxidizing them, without substantial reduction in densification, induces significant capability to achieve desirable/application oriented balance between mechanical, electrical, and catalytic properties of these ceramic nanocomposites. This novel strategy, upon further development, opens new level of opportunities for real-world/industrial applications of these relatively novel engineering materials. © 2019 by the authorsItem The high energy supercapacitor from rGO/Ni(OH)2/PANI nanocomposite with methane sulfonic acid as dopant(Academic Press Inc. apjcs@harcourt.com, 2019) Viswanathan, A.; Nityananda Shetty, A.N.The low energy densities of supercapacitors limit their utilization as energy storage and energy conversion devices. To overcome this limitation, here we present a ternary nanocomposite of reduced graphene oxide (rGO)/nickel hydroxide (Ni(OH)2/polyaniline (PANI), with methane sulfonic acid as dopant, having weight percentages of 14%:14%:72% (G14NP), respectively, as an electrode material for supercapacitor. With 1 M sulfuric acid (H2SO4) as the electrolyte, the supercapacitor yields a high energy density of 120.48 W h kg?1, comparable with those of Li-ion batteries. The G14NP also exhibits good electrochemical performance with a specific capacitance of 602.40 F g?1 and a power density of 2584.83 W kg?1, at a current density of 1 A g?1. The G14NP also exhibits a promising stability of its electrochemical performances even after 16,500 cycles at a potential scan of 400 mV s?1. Remarkably, the composite performs exceptionally well at a potential window available in an aqueous electrolyte. The sustainability to high current loading while charging and its power backup application is satisfactorily demonstrated, by charging with a commercial 9 V battery. © 2019 Elsevier Inc.Item High rate capable and high energy supercapacitor performance of reduced graphene oxide/Al(OH)3/polyaniline nanocomposite(Academic Press Inc., 2020) Viswanathan, A.; Gururaj Acharya, M.; Nityananda Shetty, A.N.The high rate capable, high energy (higher than the lead acid batteries & Nickel-cadmium batteries and comparable with Li-ion batteries) and long lasting supercapacitive performance was achieved from a ternary nanocomposite of rGO/Al(OH)3/PANI (5.88%:11.77%:82.85%) (GAlP82). The GAlP82 exhibited high cyclic stability till 47,500 cycles at 400 mV s?1, with increasing trend of specific capacitance (Cs) with increase in No. of energy storage/delivery cycles. After 41,500 cycles the GAlP82 exhibited a Cs of 490.19 F g?1, an energy density (E) of 98.03 W h kg?1 and a power density (P) of 2.2829 kW kg?1 at 1 A g?1. The GAlP82 exhibited a good rate capability by retaining 73% of Cs up to 10 A g?1 before cyclic stability study and 33% of Cs up to 23 A g?1 after 41,500 cycles; and all these impressive performances are achieved from the symmetric supercapacitor cell of GAlP82. © 2020 Elsevier Inc.Item Resonance levels in GeTe thermoelectrics: Zinc as a new multifaceted dopant(Royal Society of Chemistry, 2020) Bhat, D.K.; Shenoy, U.S.Recently doping has been widely used in enhancing the thermoelectric properties of lead-free GeTe. But much of the work has been concentrated on carrier concentration tuning or phonon scattering. Until now, only indium has been reported to be the best resonant dopant in cubic GeTe. Herein, for the first time we introduce zinc as a resonant dopant to the cubic GeTe family. We show that zinc in GeTe not only introduces resonance states but also increases the band gap and raises the heavy hole valence band above the light hole valence band leading to enhanced Seebeck values. This multifunctional dopant incorporation in GeTe leads to enhanced transport properties as predicted by Boltzmann transport properties calculations based on first principles density functional theory electronic structure calculations. This journal is © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique.Item Spatial and temporal variations in river water quality of the Middle Ganga Basin using unsupervised machine learning techniques(Springer Science and Business Media Deutschland GmbH, 2020) Krishnaraj, A.; Deka, P.C.In this study, cluster analysis (CA), principal component analysis (PCA) and correlation were applied to access the river water quality status and to understand spatiotemporal patterns in the Ganga River Basin, Uttara Pradesh. The study was carried out using data collected over 12 years (2005–2017) regarding 20 water quality parameters (WQPs) covering spatially from upstream to downstream Ankinghat to Chopan, respectively (20 stations under CWC Middle Ganga Basin). The temporal variations of river water quality were established using the Spearman non-parametric correlation coefficient test (Spearman R). The highest Spearman R (?0.866) was observed for temperature with the season and a very significant p value of (0.0000). The parameters EC, pH, TDS, T, Ca, Cl, HCO3, Mg, NO2 + NO3, SiO2 and DO had a significant correlation with the season (p < 0. 05). K-means clustering algorithm grouped the stations into four different clusters in dry and wet seasons. Based on these clusters, box and whisker plots were generated to study individual clusters in different seasons. The spatial patterns of river WQ on both seasons were examined. PCA was applied to screen out the most significant water quality parameters due to spatial and seasonal variations out of a large data set. It is a data reduction process and a more conventional way of speeding up any machine learning algorithms. A reduced number of three principal components (PCs) were drawn for 20 WQPs with an explained total variance of 75.84% and 80.57% is observed in the dry and wet season, respectively. The parameters DO, EC_ Gen, P-Tot, SO4 are the most dominating parameters with PC score more than 0.8 in the dry season; similarly, TDS, K, COD, Cl, Na, SiO2 in the wet season. The different components of water quality monitoring, such as spatiotemporal patterns, scrutinize the most relevant water quality parameters and monitoring stations are well addressed in this study and could be used for the better management of the Ganga River Basin. © 2020, Springer Nature Switzerland AG.Item Role of coconut shell biochar and earthworm (Eudrilus euginea) in bioremediation and palak spinach (Spinacia oleracea L.) growth in cadmium-contaminated soil(Academic Press, 2022) Noronha, F.R.; Manikandan, S.K.; Nair, N.The contamination of soil with heavy metals is known to affect the yield the soil fertility, which in turn affects the growth of agricultural crops. This study investigates the role of coconut shell biochar (CSB) and earthworms (Eudrilus euginea) in the bioremediation and growth of Palak spinach (Spinacia oleracea L.) in cadmium (Cd) contaminated soil. The soils were amended with different combinations of CSB and earthworms and incubated for 35 days. Later, the soil samples were analyzed for the changes in the soil properties, soil enzyme activity, and heavy metal contents. It is observed that the treatments with both CSB and earthworms resulted in the improvement of soil properties and soil enzyme activity which was directly related to soil fertility. Meanwhile, the maximum removal of 94.38% of total Cd content in the soil was obtained for the soil sample contain both CSB and earthworms. The improved soil properties resulted in a higher germination percentage of Spinacia oleracea L. seeds in the Cd contaminated soil. © 2021 Elsevier LtdItem Emphasized temperature dependent electrical properties study of fabricated ZnO/PVA/PANI nanocomposite films(Elsevier Inc., 2022) Kanavi, P.S.; Meti, S.; Fattepur, R.H.; Patil, V.B.Polyvinyl alcohol-Polyaniline composite films with different amounts of zinc oxide (ZnO) (0.2%, 0.4%, 0.6% and 1%)were prepared by in situ polymerization followed by film casting and drying. The samples, ZnO and PPZ films, were characterized by various techniques. The presence of ZnO in PPZ films was confirmed by the X-Ray Diffractometer (XRD). The surface morphology of the ZnO and PPZ films were examined by the Field-Emission Scanning Electron Microscopy(FESEM). The formation of absorption bonds corresponding to the PPZ films were illustrated by the Fourier Transform Infrared Spectroscope (FTIR)analysis. The films were found to be stable up to 150 °C, which was confirmed from the Differential Scanning Calorimetry (DSC) and Thermo-Gravimetric Analyzer (TGA) technique. The absorption peaks of PPZ, around visible and UV region, was studied by the UV–Vis spectra. The electrical conductivity plots obtained from the impedance analyzer, between frequency ranges of 10 Hz to 100 kHz, show that the increase in concentration and temperature of the samples resulted in the higher conductivity of the PPZ films. For 1% ZnO concentration at 150 °C, the AC conductivity of PPZ1 was found to be 20.06 S/m. Such conductivity behavior samples render the applicability of the PPZ films. © 2022Item A study on effect of MgO nanoparticles loading on the electrical conducting properties of polyvinyl alcohol/polyaniline polymer composite films(Springer Science and Business Media B.V., 2022) Kanavi, P.S.; Meti, S.; Fattepur, R.H.; Patil, V.B.; Hunagund, S.M.; Patil, S.A.; Inamdar, S.R.In this work, the polyvinyl alcohol/polyaniline/magnesium oxide (PPM) polymer nanocomposite films were fabricated for electrical conductivity studies. Initially, the magnesium oxide (MgO) nanoparticles were synthesized by sol–gel method. Different PPM films were fabricated by varying the weight percent (0.2, 0.4, 0.6 and 1%) of MgO in the polyvinyl alcohol/polyaniline polymer blend. The films were obtained by casting the PPM solution in the Petri-dish and dried. The crystallinity and morphology of MgO and PPM films were characterized by the X-ray diffraction spectroscopy and field emission scanning electron microscopy (FESEM). The absorption spectra of MgO and PPM films were obtained by UV–visible spectroscopy. The Fourier transform infrared (FTIR) spectra were obtained to determine the chemical nature. The thermal stability of the films was studied by the differential scanning calorimetry (DSC) and thermo-gravimetric analysis (TGA) techniques. The temperature-dependent (up to 150 °C) electrical conductivity of the PPM films was analysed by impedance equipment within the frequency band of 4 Hz to 1 MHz. The variation of MgO nanoparticles concentration in the polymer composite matrix and the increase in temperature influences the electrical conductivity of the films. Graphical Abstract: [Figure not available: see fulltext.] © 2022, The Author(s), under exclusive licence to Springer Nature B.V.