Conference Papers
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Item Mechanical and tribological behaviour of epoxy reinforced with nano-Al2O3 particles(Trans Tech Publications Ltd ttp@transtec.ch, 2014) Kurahatti, R.V.; Surendranathan, A.O.; Ramesh Kumar, A.V.; Auradi, V.; Wadageri, C.S.; Kori, S.A.In the present work systematic study has been conducted to investigate the matrix properties by introducing nanosize Al2O3 (particle size 100 nm, 0.5-10 wt %) fillers into an epoxy resin. High shear mixing process was employed to disperse the particles into the resin. The experimental results indicated that frictional coefficient and wear rate of epoxy can be reduced at rather low concentration of nano-Al2O3. The lowest specific wear rate 0.7 × 10-4 mm3/Nm is observed for the composites with 1 wt.% which is decreased by 65% as compared to unfilled epoxy. The reinforcement of Al2O3 particles leads to improved mechanical properties of the epoxy composites. The results have been supplemented with scanning electron micrographs to help understand the possible wear mechanisms. © (2014) Trans Tech Publications, Switzerland.Item Multilayer Zn-Ni-Al2O3 coatings for corrosion protection(Inderscience Publishers, 2014) Ullal, Y.; Hegde, A.C.The paper reports the development of composite coatings of Zn-Ni-Al2O3 by composition modulated multilayer (CMM) technique using m-aminophenol and gelatin as additives. The bath constituents and deposition parameters were optimised by conventional method. The role of gelatin and m-aminophenol in the bath was analysed by cyclic voltammetry (CV) study. Corrosion performance of the monolayer coatings was enhanced further by multilayer technique. The modulation in composition was effected by pulsing the DC in square-wave patterns. The coatings configurations were optimised for peak performance of the coatings against corrosion. It was found that corrosion resistance of CMM coatings increased with number of layers up to certain optimal numbers, and then decreased. Incorporation of Al2O3 particles into metal matrix was confirmed by EDAX. Formation of layered coating and their phase structures were analysed by scanning electron microscopy (SEM) and X-ray diffraction (XRD) study. Reasons responsible for better corrosion resistance of CMM composite coatings are analysed and results are discussed. Copyright © 2014 Inderscience Enterprises Ltd.Item Studies on corrosion of Mg-Al-Zn alloy in 30% aqueous ethylene glycol(Trans Tech Publications Ltd ttp@transtec.ch, 2015) Medhashree, H.; Nityananda Shetty, A.The Mg-Al-Zn alloy is used in the coolant systems of automobile engines. Corrosion of Mg-Al-Zn engine components by coolants, which consist of 30% aqueous ethylene glycol as a coolant composition, is an important issue in automobile industries. With this preview, in the present study it is intended to study the effect of environmental contaminant sulphate ions on the corrosion behavior of Mg-Al-Zn alloy in 30% (v/v) aqueous ethylene glycol solution. Electrochemical investigations were carried out by potentiodynamic polarization and electrochemical impedance spectroscopy techniques. Scanning electron microscopy (SEM) and energy dispersion X-ray analysis (EDX) were used to study the surface morphology and composition of the alloy. Activation parameters for the corrosion process were calculated by conducting the corrosion studies at different temperatures. It was observed that corrosion rate of the alloy in 30% (v/v) aqueous ethylene glycol increases with the increase in the concentration of sulphate ions and also with the increase in temperature. © (2015) Trans Tech Publications, Switzerland.Item Electrodeposited Ni-P alloy thin films for alkaline water splitting reaction(Institute of Physics Publishing michael.roberts@iop.org, 2016) Elias, L.; Damle, V.H.; Hegde, A.Ni-P alloy thin films was developed as a robust electrode material for alkaline water splitting for hydrogen evolution reaction (HER) and oxygen evolution reaction (OER), through electrodeposition technique. The influence of alloy composition, achieved through induced codeposition of the reluctant non-metal, i.e. phosphorous (P) on its electrocatalytic activity was studied, and arrived at the best composition of alloy for HER and OER. The water splitting efficacy of the alloy films was tested in 1.0 M KOH using electrochemical methods such as cyclic voltammetry and chronopotentiometry. The experimental observation shows that the alloy thin film with 9.0 wt.% of P and 4.2 wt.% of P are the best electrode materials for HER and OER, respectively. The electrocatalytic performance of alloy films towards HER and OER were related to its surface topography, composition and crystal structure through field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD) analyses, respectively. © Published under licence by IOP Publishing Ltd.Item Effective role of P2O5 on in-vitro bioactivity of soda lime phosphosilicate glasses(Elsevier Ltd, 2017) Kiran, P.; Udayashankar, N.K.; Shashikala, H.D.In-vitro bio active properties have been studied on Sol-gel derived 58SiO2-33CaO-(5-X) Na2O-(4+X) P2O5 (where X=0, 5) bio glass samples soaked for seven days in a simulated body fluid (SBF) solution. X-ray diffraction studies indicated the presence of Hydroxyl Apatite (HA) crystalline phase in the synthesized samples. The spherical shaped hydroxyl carbonated apatite (HCA) nuclei were observed under scanning electron microscope. The Fourier transform infrared (FTIR) and Raman spectroscopic analysis confirmed the presence of carbonates in the glass matrix. In particular, larger concentration of P2O5 in the bioglass resulted in superior bioactivity compared to low concentration of P2O5. © 2017 Elsevier Ltd.Item Influence of Fineness of Mineral Admixtures on the Degree of Atmospheric Mineral Carbonation(Springer Science and Business Media Deutschland GmbH info@springer-sbm.com, 2021) Farsana, C.; Das, B.B.; Snehal, K.Global carbon dioxide concentration is rising at the rate of 2 ppm every year, which had led to the demand of sustainable development. In construction industry, manufacturing of cement is the main source of global anthropogenic carbon dioxide emissions. Carbon capture and storage is a recent technology which had helped to sequester carbon dioxide from atmosphere and thus helps in reducing the greenhouse effect to a certain extent. This study mainly focuses on the atmospheric mineral carbonation of mineral admixtures like fly ash (FA), ground granulated blast furnace slag (GGBS), and silica fume (SF), which are the industrial by-products and are being treated as waste. This study also focuses on the effect of fineness of different mineral admixtures on the degree of atmospheric mineral carbonation. Fly ash with three different levels of fineness (FA, FA I, and FA II), GGBS with three different levels of fineness (GGBS, GGBS I, and GGBS II), and silica fume were mixed with activators like lime and gypsum and were left for atmospheric mineral carbonation. Mineralogical characterisations were done using X-ray diffraction (XRD), thermo gravimetric analysis (TGA), and scanning electron microscopy (SEM). Degree of carbonation of the samples was analyzed and calculated using the TGA results. From the comparative analysis of all the samples, it was found that GGBS II had highest degree of carbonation. It was also observed that calcium-based compounds like calcite, aragonite, vaterite, calcite magnesium syn, gismondine, waikarite, calcium silicate hydrate, diopside, calcium sulfate, and portlandite were formed in the samples after 45 and 90 days of atmospheric mineral carbonation. However, it was observed that with increasing levels of fineness of mineral admixtures, there was no significant change in the degree of atmospheric mineral carbonation. © 2021, Springer Nature Singapore Pte Ltd.Item Synthesis and characterization of nano-alumina powder by milling of Al and MnO2powder mixture(Elsevier Ltd, 2021) Ravikumar, K.S.; Ghanaraja, S.; Ramesh, M.R.There are extensive study on nano composites because of its outstanding mechanical properties when compared with the monolithic materials. The manufacturing of nano particles presents an increasing interest. There are two basic strategy for the synthesis of nano particles, they are bottom up and top down approach. Nano particles are built atom by atom in the bottom up approach. In the synthesis of nano particles, top down approach is most applied one. In this approach, bulk materials are broken down gradually into smaller sizes until they reach nano size. Ball milling is most widely used method for the top down approch. Ball milling process involves milling of constituent powders in a vial where mechanical deformation and chemical reactions takes place between the powders to form new phase. In the present study, constituent powder mixture of Al (1.845 μm) and MnO2(0.75 μm) are subjected to high energy planetary ball milling to form new phase which is of nano alumina (Al2O3). Initially, Al and MnO2powder mixture are taken in the ratio of 1:2.416 by weight for different milling duration of 120 min, 240 min and 360 min. The constant speed of the mill was maintained at 300 rpm. The powder mixture inside the mill subjected to impact force between ball to ball and between ball to wall of the container undergo cyclic deformation, cold welding and fracture ensures the generation of nano alumina particles in the range of 50 nm to 560 nm. The effect of mechanical alloying on the microstructure of the powder mixture have been studied by scanning electron microscope (SEM), X-ray diffraction (XRD) and EDS. Toluene was used during milling appears effective process control agent to avoid severe agglomeration and to enhance milling effect. © 2021 Elsevier Ltd. All rights reserved.Item A study on dimensional analysis modeling of crater size during wire electrical discharge turning process by using Buckingham Pi theorem(Elsevier Ltd, 2022) Naik, G.M.; Hipparagi, M.A.; Bellubbi, S.; Roy, A.; Anjan, B.N.; Ramesh, S.; Narendranath, S.The investigation on material removal by thermal erosion of discrete spark and vaporization in wire electrical discharge turning process was made to understand the crater size variation on turned components. In this study the modelling is done to establish the relationship between dependent and independent variables through Buckingham's Pi-theorem, to predict the variations of crater diameter depending on physical and thermal properties, subsequently the dimensional model was validated by conducting experiments on wire-electrical discharge turning process for two distinct density variant materials such as Aluminium 6061 and INCONEL 718 super alloys. The density, enthalpy of vaporization, radius of spark, specific heat and other quantities effect on crater diameter have been discussed in this research paper. © 2022Item Alkali Activated Black Cotton Soil with Partial Replacement of Class F Fly Ash and Areca Nut Fiber Reinforcement(Springer Science and Business Media Deutschland GmbH, 2023) Chethan, B.A.; Ravi Shankar, A.U.; Chinnabhandar, R.K.; Kumar, D.H.Alkali activation has received great attention for improving the soil properties with suitable precursor materials. Industrial byproduct class F fly ash was suitably utilized to improve Black Cotton (BC) soil properties along with ordinary Portland cement by various researchers. However, the CO2 emission associated with cement production has enforced the evaluation of alternative binders. Laboratory investigations were conducted on BC soil by admixing various fly ash dosages (0–50%) and reinforcing the mix with 0.5% areca nut fiber. Alkali activator solution prepared using 8 molar sodium hydroxide solution (SH) and sodium silicate solution (SS) at 1.5 SS/SH ratio showed significant improvement in Unconfined Compressive Strength (UCS) of stabilized BC soil on 7 and 28 days curing. The reinforcement was effective in improving the flexural strength of stabilized mixes. Exorbitant unsoaked California Bearing Ratio (CBR) values were observed on 28 days of curing. However, the samples could retain low soaked CBR values despite reinforcement. Scanning Electron Microscope (SEM) images showed the reduction of shrinkage cracks and strong bonding of fibers in the stabilized mix. X-Ray Diffraction (XRD) patterns evidenced the formation of various hydration products due to the alkali reaction, which resulted in the high strength gain of mixes at ambient temperature curing. The leaching of mineral constituents from the set mix lead to the failure of durability samples. Due to nondurability, the alkali activation with a selected precursor cannot suit pavement materials requirements. © 2023, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.Item Examining the Effect of Diverse Calcium Sources on Cement Mortar Using Bacillus Subtilis Through MICP: A Preliminary Investigation(Springer Science and Business Media Deutschland GmbH, 2024) Hosamane, C.C.; Chaudhary, P.; Palanisamy, T.Calcite, a crystal form of calcium carbonate, plays a crucial role in Microbially Induced Calcium Carbonate Precipitation (MICP). In this process, bacteria aid in forming calcite crystals, strengthening materials like mortar. Bacteria interact with calcium ions, causing calcite to precipitate, thus enhancing the strength and durability of the cement matrix. This study presents a method to improve cement mortar properties through MICP. Gram-positive Bacillus subtilis bacteria were introduced into cubes containing four different calcium sources: calcium chloride, calcium hydroxide, calcium lactate, and calcium oxide. After curing for 7, 14, and 28 days, calcium carbonate quantification, EDTA testing, and compressive strength testing were conducted on the mortar cubes. Results showed that cubes with calcium chloride exhibited peak compressive strengths of approximately 37.4 MPa, 45.7 MPa, and 58 MPa after each respective curing duration. This highlights the superior performance of cubes with CaCl2 compared to other calcium sources. The increase in strength and decrease in water absorption is attributed to the proliferation of calcite crystals within the cement matrix voids, confirmed by microstructural analyses using scanning electron microscopy (SEM). © The Author(s), under exclusive license to Springer Nature Switzerland AG 2024.