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    Phase transformation, structural evolution, and mechanical property of nanostructured feal as a result of mechanical alloying
    (Springer New York LLC barbara.b.bertram@gsk.com, 2009) Rajath Hegde, M.M.R.; Surendranathan, A.O.
    The objective of the work is to synthesize nanostructured FeAl alloy powder by mechanical alloying (MEA). The work concentrates on the synthesis, characterization, and structural and mechanical properties of the alloy. Nanostructured FeAl intermetallics are prepared directly by MEA in a high-energy ball mill. Milling is performed under toluene solution to avoid contamination from the milling media and atmosphere. Mixtures of elemental Fe and Al are progressively transformed into a partially disordered solid solution with an average composition of Fe-50 at.% Al. Phase transformation, structural changes, morphology, particle size measurement, and chemical composition during MEA are investigated by X ray diffraction (XRD), scanning electron microscopy (SEM), and energy dispersive x-ray spectroscopy (EDS). Vickers microhardness (VMH) indentation tests are performed on the powders. The XRD and SEM studies reveal the alloying of elemental powders as well as transition to nanostructured alloy; crystallite size of 18 nm is obtained after 28 h of milling. Expansion/contraction in lattice parameter accompanied by reduction in crystallite size occurs during transition to nanostructured alloy. Longer milling introduces ordering in the alloyed powders as proved by the presence of superlattice reflection. Elemental and alloyed phases coexist while hardness increases during MEA. copy2009 Springer Science+Business Media, Inc.
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    Phase transformation, structural evolution and mechanical property of nanostructured FeAl as a result of mechanical alloying
    (2009) Rajath Hegde, M.M.R.; Surendranathan, A.O.
    Objective of the work was to synthesize nanostructured FeAl alloy powder by mechanical alloying (MEA). The work concentrated on synthesis, characterization, structural and mechanical properties of the alloy. Nanostructured FeAl intermetallics were prepared directly by MEA in a high energy rate ball mill. Milling was performed under toluene solution to avoid contamination from the milling media and atmosphere. Mixtures of elemental Fe and Al were progressively transformed into a partially disordered solid solution with an average composition of Fe-50 at % Al. Phase transformation, structural changes, morphology, particle size measurement and chemical composition during MEA were investigated by X-ray diffraction (XRD), Scanning electron microscopy (SEM) and Energy dispersive X-ray spectroscopy (EDS) respectively. Vickers micro hardness (VMH) indentation tests were performed on the powders. XRD and SEM studies revealed the alloying of elemental powders as well as transition to nanostructured alloy, crystallite size of 18 nm was obtained after 28 hours of milling. Expansion/contraction in lattice parameter accompanied by reduction in crystallite size occurs during transition to nanostructured alloy. Longer milling duration introduces ordering in the alloyed powders as proved by the presence of superlattice reflection. Elemental and alloyed phase coexist while hardness increased during MEA. © 2009 Allerton Press, Inc.
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    Adsorption of benzene vapor onto activated biomass from cashew nut shell: Batch and column study
    (Bentham Science Publishers, 2012) Suresh, S.; Vijayalakshmi, G.; Rajmohan, B.; Subbaramaiah, V.
    The preparation of chemically modified activated cashew nut shell (ACNSB) of different impregnation ratios and their effects in adsorption of benzene vapor were studied. Effects of chemical pre-impregnation using phosphoric acid at different ratios (1:1 and 2:1) were investigated in order to patent. Physico-chemical characterization including surface area, scanning electron microscopy, energy dispersive X-ray spectroscopy, High-resolution Transmission Electron Microscopy and Fourier transform infrared spectroscopy of the ACNSB before and after benzene adsorption have been done to understand the adsorption mechanism. Optimum conditions for benzene removal were found to be, adsorbent dose m=10 g/l of solution and time (t) 120 min for the C0 range of 300-500 mg/l. Adsorption of benzene followed pseudosecond-order kinetics. Langmuir and R-P isotherms were found to best represented data for benzene adsorption onto ACSNB. In ACNSB column experiments, it can be concluded that concentration of benzene increases with the longer breakthrough time and hence higher adsorption capacity. ACSNB are many advantages includes simple and fast, organic solvent recovery, economical, energy savings, environmentally safe aspect and minimize the waste management problem. © 2012 Bentham Science Publishers.
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    Influence of 2-(4-chlorophenyl)-2-oxoethyl benzoate on the hydrogen evolution and corrosion inhibition of 18 Ni 250 grade weld aged maraging steel in 1.0 M sulfuric acid medium
    (2012) Sanatkumar, B.S.; Nayak, J.; Nityananda Shetty, A.N.
    Electrochemical corrosion behavior and hydrogen evolution reaction of weld aged maraging steel have been investigated, in 1.0 M sulfuric acid solution containing different concentrations of 2-(4-chlorophenyl)-2-oxoethyl benzoate (CPOB). The data obtained from polarization technique showed that the corrosion current density (i corr) and the hydrogen evolution rate decrease, indicating a decrease in the corrosion rate of weld aged maraging steel as well as an increase in the inhibition efficiency (?%) with the increase in inhibitor concentration. Changes in impedance parameters were indicative of adsorption of CPOB on the metal surface, leading to the formation of protective film. Both activation (E a) and thermodynamic parameters (?G ads 0, ?H ads 0 and ?S ads 0) were calculated and discussed. The adsorption of CPOB on the weld aged maraging steel surface obeyed the Langmuir adsorption isotherm model. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) study confirmed the formation of an adsorbed protective film on the metal surface. © 2012, Hydrogen Energy Publications, LLC. Published by Elsevier Ltd. All rights reserved.
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    Cadmium (II) and nickel (II) biosorption by Bacillus laterosporus (MTCC 1628)
    (Taiwan Institute of Chemical Engineers, 2014) Kulkarni, R.; Shetty K, V.; Srinikethan, G.
    Biosorption of heavy metals is a promising technology that involves removal of toxic metals from industrial waste streams and natural waters. The study describes the sorption of cadmium (II) [Cd (II)] and nickel (II) [Ni (II)] by dead biomass of Bacillus laterosporus, MTCC 1628. The biosorption conditions for the removal of Cd (II) and Ni (II) were examined by studying the effect of pH, contact time, biosorbent dosage and initial metal ion concentration. Shake flask studies yielded adsorption equilibrium in almost 120. min, for both the metals. It was found from Langmuir model that the maximum adsorption capacity for Cd (II) and Ni (II) ions was 85.47. mg/g and 44.44. mg/g respectively. Kinetic evaluation of the experimental data showed that the biosorption process followed pseudo-second order kinetics. Thermodynamic analysis showed that biosorption is an endothermic process with ?. H° of 5.45. kJ/mol for Cd (II) biosorption and 24.33. kJ/mol for Ni (II) biosorption. The surface characteristics of B. laterosporus biomass before and after metal biosorption were analyzed by using scanning electron microscope (SEM) with energy dispersive X-ray spectroscopy (EDAX) to study the changes in surface morphology and elemental constitution of the adsorbent. B. laterosporus exhibited a higher and better potential biosorbent for the removal of Cd (II) as compared to Ni (II) from aqueous solution. © 2013 Taiwan Institute of Chemical Engineers.
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    RGO supported Co-Ni bimetallic magnetically separable nanocatalysts for the reduction of 4-Nitrophenol
    (Elsevier Ltd, 2016) Prasad, R.; Lolakshi, M.K.; Badekai Ramachandra, B.R.
    The Cobalt-Nickel-reduced graphene oxide ternary composite was prepared using eco-friendly, solvent-free and low temperature CVD method where in metal formates were used as metal precursor. The structure, composition and morphology of synthesized samples were characterized by several related techniques like X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), energy dispersive X-ray spectroscopy (EDS), transmission electron microscopy (TEM) and X-ray photoelectron spectroscopy (XPS). The catalytic efficiency towards reduction of an organic pollutant such as 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) was explored and the reaction parameters like temperature, weight ratio of the composite was optimised and rate constant of the reactions were measured. The results show 8% Co-Ni-rGO are having high catalytic efficiency and can complete the reduction reaction within 250 s at 45 °C. Furthermore, catalyst being magnetically separable shows high stability after ten successive reactions. Hence, the Co-Ni-rGO composite can be a potential promising material to catalyse the reduction of 4-NP. © 2016 Elsevier B.V. All rights reserved.
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    Hydrous Cerium Oxide Nanoparticles Impregnated Enteromorpha sp. for the Removal of Hexavalent Chromium from Aqueous Solutions
    (American Society of Civil Engineers (ASCE) onlinejls@asce.org, 2016) Selvasembian, S.; Selvaraju, N.; Raj Mohan, B.; Muhammed Anzil, P.K.; Amith, K.D.; Ushakumary, E.R.
    A novel nanobiocomposite, hydrous cerium oxide nanoparticles impregnated Enteromorpha sp. (HCONIE) was used effectively for the adsorption of Cr(VI) from aqueous solutions. The chemical and structural characteristics of the nanobiocomposite were investigated using Fourier transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDX) analysis. Adsorption studies were determined as a function of pH, contact time, initial concentration of Cr(VI), HCONIE dose, and temperature. The equilibrium adsorption data were modeled using two parameter isotherms, including Langmuir, Freundlich, Dubinin-Radushkevich (D-R), Temkin, Jovanovic, Halsey, and Harkin-Jura. Adsorption data were well described by the Freundlich and Halsey isotherm. The kinetics data were analyzed using adsorption kinetic models like the pseudo-first-order, pseudo-second-order and intraparticle diffusion equation. Kinetic data showed good agreement with the pseudo-second-order kinetic model. The obtained thermodynamic parameters showed that the adsorption of Cr(VI) onto the HCONIE was exothermic in nature. The presence of foreign ions showed a decreased effect on the adsorption capacity of HCONIE towards Cr(VI) removal. The desorption study was carried out with 0.1 and 0.5 M of three different desorbing agents. The study suggests that HCONIE nanobiocomposite could be used for the removal of Cr(VI) from aqueous solution. © 2015 American Society of Civil Engineers.
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    Development and properties evaluation of Mg-6% Zn/Al multilayered composites processed by accumulative roll bonding
    (Cambridge University Press, 2017) Anne, G.; Ramesh, M.R.; Shivananda Nayaka, H.; Arya, S.B.; Sahu, S.
    Accumulative roll bonding (ARB) process was used to develop Mg-6% Zn/Al and Mg-6% Zn/anodized-Al multilayered composites. Microstructural characterization was done using scanning electron microscopy, energy-dispersive X-ray spectroscopy, electron backscattered diffraction, and transmission electron microscopy. An average grain size measured in the roll-bonded layers of Al, anodized Al, and Mg-2% Zn was found to be 1.8 ?m, 1.6 ?m, and 0.6 ?m, respectively. Phases Al17Mg12, AlMg4Zn11, and Al2O3 after 5-pass of ARB were confirmed by X-ray diffraction analysis. The Mg-6% Zn/Al and Mg-6% Zn/anodized Al composites exhibited tensile strengths ?252 MPa and ?256 MPa, respectively, after a 5-pass ARB process. Hardness of the individual layers of composite increased linearly with an increase in the number of ARB passes. Fractographs of the multilayered composite illustrated the ductile failure in Al and anodized Al layers and transgranular brittle fracture in Mg-6% Zn layers. © Materials Research Society 2017.
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    Synthesis of effective electrocatalyst for water splitting application from simple Cu-Ni bath
    (Allerton Press Incorporation journals@allertonpress.com, 2017) Elias, L.; Banjan, R.U.; Hegde, A.C.
    Electrocatalytically active Cu-Ni alloy coatings have been developed from a simple electrolyte having only Cu+2 and Ni+2 ions, without the use of any additive. Electrocatalytic character of the coatings was tested for their hydrogen evolution reaction (HER) and oxygen evolution reaction (OER) in 1.0 M KOH medium, alongside with their corrosion behaviours. Cyclic voltammetry and chronopotentio-metry study revealed that the deposition current density has a prominent role on the alkaline water splitting behaviour of the coatings, depending on their phase structure, composition and surface morphology. It was found that the c.d. has an inverse dependence on HER and OER. The Cu-Ni alloy coatings developed, respectively at 3.0 and 4.0 A dm–2, were found to be the best coatings for HER and OER, depending on the surface morphology. The electrocatalytic activity of Cu-Ni alloy coating for HER, deposited at 3.0 A dm–2 (optimal), was further improved through electrochemical dissolution of the as-deposited coating. The increase in the electrocatalytic activity for HER has been attributed to the enhancement in the exposed surface area of Ni active sites due to the leaching of Cu from the alloy matrices, evidenced by the energy-dispersive X-ray spectroscopy and scanning electron microscopy. The dependencies of HER and OER on to the surface of Cu-Ni alloy coatings were analysed in terms of deposition c.d. of the coatings, and the results are discussed. © 2017, Allerton Press, Inc.
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    Porous nickel telluride nanostructures as bifunctional electrocatalyst towards hydrogen and oxygen evolution reaction
    (Elsevier Ltd, 2017) Bhat, K.S.; Barshilia, H.C.; Nagaraja, H.S.
    Electrochemical water splitting technology has attracted researchers for the development of next generation fuels. Herein, we report the synthesis of nanostructured porous hollow nickel telluride nanosheets and their use as bifunctional electrocatalyst towards hydrogen and oxygen evolution reaction, anticipating an enhanced performance owing to their 2D sheet like morphology, conductivity, porous nature providing larger catalytic surface for water splitting reaction. In this regard, nickel telluride nanostructures were synthesized via an anion-exchange-reaction between pre-synthesized nickel hydroxide hexagonal nanosheets and tellurium ions under hydrothermal conditions. The as-synthesized nanostructures were characterized for structural, morphological and compositional properties using X-ray diffraction, X-ray photoelectron spectroscopy, scanning electron microscopy, high resolution transmission electron microscopy and energy dispersive X-ray spectroscopy. Nickel telluride modified electrodes were tested as bifunctional electrocatalyst under acidic and alkaline conditions, through linear sweep voltammetry and constant current chronopotentiometry methods. The modified electrodes revealed an onset potential of ?422 mV and 87.4 mV dec?1 Tafel slope towards HER and overpotential of 679 mV and 151 mV dec?1 Tafel slope towards OER. The lower onset potentials are complimented with excellent electrocatalytic stability. © 2017 Hydrogen Energy Publications LLC