443 results on '"L. John"'
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2. Effective microwave assisted synthesis of CoFe2O4@TiO2@rGO ternary nanocomposites for the synergic sonophotocatalytic degradation of tetracycline and c antibiotics
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R. Esther Nimshi, J. Judith Vijaya, L. John Kennedy, P. Stephen Selvamani, M. Bououdina, and P. Joice Sophia
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Process Chemistry and Technology ,Materials Chemistry ,Ceramics and Composites ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2023
3. Configuring Nd0.7Ca0.3Mn1-xNixO3 perovskite nanocomposites with magnetocaloric performance
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P. Amalthi, J. Judith Vijaya, L. John Kennedy, A. Mustafa, M. Bououdina, K.P. Shinde, and D.H. Kim
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Process Chemistry and Technology ,Materials Chemistry ,Ceramics and Composites ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials - Published
- 2022
4. Emerging trends in biomass-derived porous carbon materials for energy storage application: A critical review
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Priya, D. Siva, primary, Kennedy, L. John, additional, and Anand, G. Theophil, additional
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- 2023
- Full Text
- View/download PDF
5. Effective conversion of waste banana bract into porous carbon electrode for supercapacitor energy storage applications
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Priya, D. Siva, primary, Kennedy, L. John, additional, and Anand, G. Theophil, additional
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- 2023
- Full Text
- View/download PDF
6. Synthesis and thermal properties of two novel cobalt (II) Schiff's base complexes as precursors for coating cobalt oxide (Co3O4) thin film by a Plasma Enhanced Metallo-Organic Chemical Vapour Deposition
- Author
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Roniboss, A., primary, Sindhu, S., additional, Kennedy, L. John, additional, and Arockiasamy, S., additional
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- 2023
- Full Text
- View/download PDF
7. Magnetically recoverable Nd0.7Ca0.3Mn1-Ni O3 polygonal-shaped perovskite nanophotocatalysts for efficient visible-light degradation of methylene blue and tetracycline
- Author
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Amalthi, P., primary, Vijaya, J. Judith, additional, Kennedy, L. John, additional, Mustafa, A., additional, and Bououdina, M., additional
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- 2022
- Full Text
- View/download PDF
8. Common Genetic Variation and Age of Onset of Anorexia Nervosa
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Watson, Hunna J., primary, Thornton, Laura M., additional, Yilmaz, Zeynep, additional, Baker, Jessica H., additional, Coleman, Jonathan R.I., additional, Adan, Roger A.H., additional, Alfredsson, Lars, additional, Andreassen, Ole A., additional, Ask, Helga, additional, Berrettini, Wade H., additional, Boehnke, Michael, additional, Boehm, Ilka, additional, Boni, Claudette, additional, Buehren, Katharina, additional, Bulant, Josef, additional, Burghardt, Roland, additional, Chang, Xiao, additional, Cichon, Sven, additional, Cone, Roger D., additional, Courtet, Philippe, additional, Crow, Scott, additional, Crowley, James J., additional, Danner, Unna N., additional, de Zwaan, Martina, additional, Dedoussis, George, additional, DeSocio, Janiece E., additional, Dick, Danielle M., additional, Dikeos, Dimitris, additional, Dina, Christian, additional, Djurovic, Srdjan, additional, Dmitrzak-Weglarz, Monika, additional, Docampo-Martinez, Elisa, additional, Duriez, Philibert, additional, Egberts, Karin, additional, Ehrlich, Stefan, additional, Eriksson, Johan G., additional, Escaramís, Geòrgia, additional, Esko, Tõnu, additional, Estivill, Xavier, additional, Farmer, Anne, additional, Fernández-Aranda, Fernando, additional, Fichter, Manfred M., additional, Föcker, Manuel, additional, Foretova, Lenka, additional, Forstner, Andreas J., additional, Frei, Oleksandr, additional, Gallinger, Steven, additional, Giegling, Ina, additional, Giuranna, Johanna, additional, Gonidakis, Fragiskos, additional, Gorwood, Philip, additional, Gratacòs, Mònica, additional, Guillaume, Sébastien, additional, Guo, Yiran, additional, Hakonarson, Hakon, additional, Hauser, Joanna, additional, Havdahl, Alexandra, additional, Hebebrand, Johannes, additional, Helder, Sietske G., additional, Herms, Stefan, additional, Herpertz-Dahlmann, Beate, additional, Herzog, Wolfgang, additional, Hinney, Anke, additional, Hübel, Christopher, additional, Hudson, James I., additional, Imgart, Hartmut, additional, Jamain, Stephanie, additional, Janout, Vladimir, additional, Jiménez-Murcia, Susana, additional, Jones, Ian R., additional, Julià, Antonio, additional, Kalsi, Gursharan, additional, Kaminská, Deborah, additional, Kaprio, Jaakko, additional, Karhunen, Leila, additional, Kas, Martien J.H., additional, Keel, Pamela K., additional, Kennedy, James L., additional, Keski-Rahkonen, Anna, additional, Kiezebrink, Kirsty, additional, Klareskog, Lars, additional, Klump, Kelly L., additional, Knudsen, Gun Peggy S., additional, La Via, Maria C., additional, Le Hellard, Stephanie, additional, Leboyer, Marion, additional, Li, Dong, additional, Lilenfeld, Lisa, additional, Lin, Bochao, additional, Lissowska, Jolanta, additional, Luykx, Jurjen, additional, Magistretti, Pierre, additional, Maj, Mario, additional, Marsal, Sara, additional, Marshall, Christian R., additional, Mattingsdal, Morten, additional, Meulenbelt, Ingrid, additional, Micali, Nadia, additional, Mitchell, Karen S., additional, Monteleone, Alessio Maria, additional, Monteleone, Palmiero, additional, Myers, Richard, additional, Navratilova, Marie, additional, Ntalla, Ionna, additional, O’Toole, Julie K., additional, Ophoff, Roel A., additional, Padyukov, Leonid, additional, Pantel, Jacques, additional, Papežová, Hana, additional, Pinto, Dalila, additional, Raevuori, Anu, additional, Ramoz, Nicolas, additional, Reichborn-Kjennerud, Ted, additional, Ricca, Valdo, additional, Ripatti, Samuli, additional, Ripke, Stephan, additional, Ritschel, Franziska, additional, Roberts, Marion, additional, Rotondo, Alessandro, additional, Rujescu, Dan, additional, Rybakowski, Filip, additional, Scherag, André, additional, Scherer, Stephen W., additional, Schmidt, Ulrike, additional, Scott, Laura J., additional, Seitz, Jochen, additional, Silén, Yasmina, additional, Šlachtová, Lenka, additional, Slagboom, P. Eline, additional, Slof-Op ‘t Landt, Margarita C.T., additional, Slopien, Agnieszka, additional, Sorbi, Sandro, additional, Świątkowska, Beata, additional, Tortorella, Alfonso, additional, Tozzi, Federica, additional, Treasure, Janet, additional, Tsitsika, Artemis, additional, Tyszkiewicz-Nwafor, Marta, additional, Tziouvas, Konstantinos, additional, van Elburg, Annemarie A., additional, van Furth, Eric F., additional, Walton, Esther, additional, Widen, Elisabeth, additional, Zerwas, Stephanie, additional, Zipfel, Stephan, additional, Bergen, Andrew W., additional, Boden, Joseph M., additional, Brandt, Harry, additional, Crawford, Steven, additional, Halmi, Katherine A., additional, Horwood, L. John, additional, Johnson, Craig, additional, Kaplan, Allan S., additional, Kaye, Walter H., additional, Mitchell, James E., additional, Olsen, Catherine M., additional, Pearson, John F., additional, Pedersen, Nancy L., additional, Strober, Michael, additional, Werge, Thomas, additional, Whiteman, David C., additional, Woodside, D. Blake, additional, Gordon, Scott, additional, Maguire, Sarah, additional, Larsen, Janne T., additional, Parker, Richard, additional, Petersen, Liselotte V., additional, Jordan, Jennifer, additional, Kennedy, Martin, additional, Wade, Tracey D., additional, Birgegård, Andreas, additional, Lichtenstein, Paul, additional, Landén, Mikael, additional, Martin, Nicholas G., additional, Mortensen, Preben Bo, additional, Breen, Gerome, additional, and Bulik, Cynthia M., additional
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- 2022
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9. Synergic effect of Cu2O/MoS2/rGO for the sonophotocatalytic degradation of tetracycline and ciprofloxacin antibiotics
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A. Mustafa, M. Bououdina, P. Stephen Selvamani, R. Jothi Ramalingam, L. John Kennedy, J. Judith Vijaya, and P. Joice Sophia
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010302 applied physics ,Materials science ,Nanocomposite ,Tetracycline ,Process Chemistry and Technology ,Composite number ,Kinetics ,Nanoparticle ,02 engineering and technology ,021001 nanoscience & nanotechnology ,01 natural sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Reaction rate constant ,0103 physical sciences ,Materials Chemistry ,Ceramics and Composites ,medicine ,Degradation (geology) ,0210 nano-technology ,Ternary operation ,Nuclear chemistry ,medicine.drug - Abstract
A ternary Cu2O/MoS2/rGO (Cu2MG) composite, synthesized by cost-efficient and eco-friendly microwave method, is potentially used for the sonophotocatalytic (visible light and ultrasonic irradiation) degradation of antibiotics namely tetracycline and ciprofloxacin. SEM and TEM observations reveal that the spherical Cu2O nanoparticles are decorated with MoS2 and rGO layered sheets. Furthermore, the incorporation of MoS2/rGO binary composite to Cu2O nanoparticles results in the reduction in fast electron-hole recombination and improve charge carrier ability of Cu2MG composite as confirmed by PL analysis. The Cu2MG composite demonstrates the synergic sonophotocatalytic degradation of Tetracycline (20 mg/L) and Ciprofloxacin (10 mg/L) antibiotics with high efficiency of 100% and 94% within a short duration of 10 min and 75 min, respectively. The kinetics study indicates that the degradation process obeys a pseudo-first order reaction with a rate constant as Ksonophotocatalytic > Kphotocatalytic > Ksonocatalytic. The high synergic value of 3.83 and 1.71 has been achieved for the degradation of TC and CIP antibiotics, respectively. The synergic effect of degradation is owing to the spontaneous production of OH˙ and ˙O2− radicals favoring free electrons to actively participate in the degradation process. This research work proves that the as-fabricated ternary Cu2MG nanocomposite is an efficient candidate for the degradation of antibiotics for better environmental protection.
- Published
- 2021
10. Emerging trends in biomass-derived porous carbon materials for energy storage application: A critical review
- Author
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D. Siva Priya, L. John Kennedy, and G. Theophil Anand
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Renewable Energy, Sustainability and the Environment ,General Materials Science ,General Chemistry - Published
- 2023
11. Magnetically recoverable Mg substituted zinc ferrite nanocatalyst for biodiesel production: Process optimization, kinetic and thermodynamic analysis
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Anchu Ashok, T. Ratnaji, L. John Kennedy, R. Gnana Pragash, and J. Judith Vijaya
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Biodiesel ,Materials science ,060102 archaeology ,Renewable Energy, Sustainability and the Environment ,020209 energy ,06 humanities and the arts ,02 engineering and technology ,Activation energy ,Transesterification ,Endothermic process ,Catalysis ,Zinc ferrite ,Reaction rate constant ,Chemical engineering ,Biodiesel production ,0202 electrical engineering, electronic engineering, information engineering ,0601 history and archaeology - Abstract
The purpose of this work is to develop a magnetically recoverable magnesium substituted zinc ferrite nanocatalysts for production of biodiesel from waste cooking oil. Microwave assisted combustion process were employed to synthesis the nanocatalyst. The catalyst were characterized by XRD, FTIR, HR-SEM, EDX, DRS and VSM analysis. The VSM study revealed a relatively high magnetic moment and high saturation magnetization property useful for magnetic separation of the catalyst from the reaction medium. Biodiesel conversion of 99.9% was achieved at the optimized reaction conditions like 3 wt% of Mg2+ doped ZnFe2O4 nanocatalyst (ZnMgF5 sample), reaction temperature about 65ᵒC, methanol-oil molar ratio of 18:1 and reaction time 30 min. Investigation on the transesterification kinetics using ZnMgF5 revealed the rate constants ranging from 0.0375 min−1 to 0.2382 min−1, activation energy Eg = 52 kJ mol−1 and frequency factor A = 2.31 × 107 min−1. The negative values of entropy (ΔS°) indicates, increased randomness of the system. Thermodynamic parameters ΔG° = 87.17 kJ mol−1 at 338 K and ΔH° = 49.31 kJ mol−1 indicate that the transesterification reaction is non-spontaneous and endothermic in nature. The magnetically separated catalyst retained 94% of biodiesel yield even after ten cycles of recovery showing a very good performance.
- Published
- 2021
12. Magnetically separable Zn1-xCuxFe2O4 (0 ≤ x ≤ 0.5) nanocatalysts for the transesterification of waste cooking oil
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L. John Kennedy, Anchu Ashok, J. Judith Vijaya, and T. Ratnaji
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Materials science ,General Chemical Engineering ,Spinel ,Analytical chemistry ,chemistry.chemical_element ,02 engineering and technology ,Transesterification ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Copper ,Nanomaterial-based catalyst ,0104 chemical sciences ,Catalysis ,Zinc ferrite ,chemistry ,Mechanics of Materials ,Biodiesel production ,engineering ,Crystallite ,0210 nano-technology - Abstract
Copper doped zinc ferrite Zn1-xCuxFe2O4 (0 ≤ x ≤ 0.5) spinels were synthesized via sonication assisted microwave method. The prepared nanoparticles were characterized by XRD, FTIR, HR-SEM, EDX, DRS and VSM analysis. Average crystallite size were in range 5.84 nm to 8.55 nm. FTIR results reveal, bands at 420 cm−1 (Zn2+ O2−) and 547 cm−1 (Fe3+ O2−) confirming tetrahedral and octahedral positions of the spinel structure formation. All the samples showed ferromagnetic behavior at room temperature. The Zn0.5Cu0.5Fe2O4 sample showed high saturation magnetization (Ms = 74.09 emu/g) and high magnetic moment (3.0 μB). The prepared magnetic nano spinels were subsequently employed to evaluate the catalytic activity for biodiesel production. The transesterification process followed pseudo first order rate kinetic model. An excellent catalytic activity for biodiesel production was acheived (98.9%) and the catalyst was recoverable quickly using an external magnet.
- Published
- 2020
13. Growth, Quantum Chemical Computations, NLO and Spectroscopic Studies of 2-Amino 5-Chloro Pyridine Single Crystal in Comparison with Certain Aminopyridine Derivatives
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Nimmy L. John, Sunila Abraham, Jesby George, P. Aswathy, and V. Sivasubramani
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Inorganic Chemistry ,Organic Chemistry ,Spectroscopy ,Analytical Chemistry - Published
- 2023
14. Synthesis and thermal properties of two novel cobalt (II) Schiff's base complexes as precursors for coating cobalt oxide (Co3O4) thin film by a Plasma Enhanced Metallo-Organic Chemical Vapour Deposition
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A. Roniboss, S. Sindhu, L. John Kennedy, and S. Arockiasamy
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Inorganic Chemistry ,Organic Chemistry ,Spectroscopy ,Analytical Chemistry - Published
- 2023
15. Magnetically recoverable Nd0.7Ca0.3Mn1-Ni O3 polygonal-shaped perovskite nanophotocatalysts for efficient visible-light degradation of methylene blue and tetracycline
- Author
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P. Amalthi, J. Judith Vijaya, L. John Kennedy, A. Mustafa, and M. Bououdina
- Subjects
General Materials Science ,General Chemistry ,Condensed Matter Physics - Published
- 2022
16. Design of copper (II) oxide nanoflakes decorated with molybdenum disulfide@reduced graphene oxide composite as an electrode for high performance supercapacitor
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Selvamani, P. Stephen, primary, Vijaya, J. Judith, additional, Kennedy, L. John, additional, Saravanakumar, B., additional, Bououdina, M., additional, and Rajabathar, Jothi Ramalingam, additional
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- 2021
- Full Text
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17. Facile microwave synthesis of cerium oxide@molybdenum di-sulphide@reduced graphene oxide ternary composites as high performance supercapacitor electrode
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Selvamani, P. Stephen, primary, Vijaya, J. Judith, additional, Kennedy, L. John, additional, Saravanakumar, B., additional, Selvam, N. Clament Sagaya, additional, and Sophia, P. Joice, additional
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- 2021
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18. High-temperature oxidation and hot corrosion behavior of Er2Sn2O7 + Inconel 625 composite
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S. Sundaravignesh, Mukiri Soban Babu, N. Dharuman, M. Kiruba, L. John Berchmans, S. Sankarapandian, V. Prabu, and Gosipathala Sreedhar
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Materials science ,Composite number ,Oxide ,Pyrochlore ,02 engineering and technology ,engineering.material ,01 natural sciences ,Corrosion ,Thermal barrier coating ,Metal ,chemistry.chemical_compound ,0103 physical sciences ,Materials Chemistry ,Yttria-stabilized zirconia ,010302 applied physics ,Process Chemistry and Technology ,Metallurgy ,021001 nanoscience & nanotechnology ,Inconel 625 ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,chemistry ,visual_art ,Ceramics and Composites ,visual_art.visual_art_medium ,engineering ,0210 nano-technology - Abstract
In this work, a strategically designed method is employed to attain the oxidation and hot corrosion rate constants of thermal barrier oxide materials without being developed as coatings. For this, low thermal conducting oxide, Er2Sn2O7 is considered as thermal barrier oxide material and blended with metallic Inconel 625 in 1:1 wt ratio to make composite. The oxidation and hot corrosion experiments conducted on bare Inconel 625, Er2Sn2O7 + 50 wt % In 625 and YSZ +50 wt % In 625 samples. The oxidation and hot corrosion results indicate that Er2Sn2O7 pyrochlore showed superior performance than that of YSZ. This work also addresses the role of Cr on destabilization, which may be interesting for fundamental understanding.
- Published
- 2019
19. Structural, optical, and magnetic properties of Ca2+ doped La2CuO4 perovskite nanoparticles
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M. Bououdina, J. Judith Vijaya, L. John Kennedy, B. Al-Najar, Gopinath Mudhana, and M. Sukumar
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010302 applied physics ,Materials science ,Diffuse reflectance infrared fourier transform ,Band gap ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,Surfaces, Coatings and Films ,Crystallography ,Tetragonal crystal system ,Paramagnetism ,0103 physical sciences ,Grain boundary ,Orthorhombic crystal system ,Crystallite ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Instrumentation - Abstract
Ca2+ substituted La2CuO4 (LCC) perovskite nanostructures have been prepared by microwave combustion. X-ray diffraction analysis indicates that the undoped La2CuO4 (LCC0) crystallizes within a single perovskite-type phase with an orthorhombic crystal structure. For smaller Ca2+ doping of 0.1 (LCC1), a minor impurity was observed, while for concentrations 0.2 (LCC2) and 0.3 (LCC3), orthorhombic-to-tetragonal phase transformation occurs. In contrast, the tetragonal phase disappears at 0.4 and 0.5 (LCC4 and LCC5) as confirmed by XRD and Rietveld refinements. The orthorhombic and tetragonal perovskite phases have an average crystallite size in range 34.2–54.3 nm and 39.8–39.4 nm, respectively. Fourier transform infrared spectroscopy study established the characteristic absorption bands of La2CuO4 perovskite orthorhombic structure; the correlated bands are observed at 683 cm−1 for La-O and 516 cm−1 for Cu-O stretching modes. The optical band gap as determined by diffuse reflectance spectroscopy (DRS) increases then decreases with increasing Ca2+ content due to the quantum confinement effect. The surface morphology observations using scanning electron microscopy display nano-sized pores and pore walls are fused grain boundaries. Magnetization-field curves exhibit a ferro-/paramagnetic behavior for undoped La2CuO4 while Ca-doped system has only a paramagnetic behavior due to the exchange of A and B sites within La2CuO4 host lattice.
- Published
- 2019
20. Facile synthesis of Fe3+ doped La2CuO4/LaFeO3 perovskite nanocomposites: Structural, optical, magnetic and catalytic properties
- Author
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M. Sukumar, J. Judith Vijaya, B. Al-Najar, L. John Kennedy, and M. Bououdina
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010302 applied physics ,Nanocomposite ,Materials science ,Band gap ,Mechanical Engineering ,Doping ,02 engineering and technology ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,law.invention ,Paramagnetism ,Chemical engineering ,Mechanics of Materials ,law ,0103 physical sciences ,General Materials Science ,Orthorhombic crystal system ,Crystallite ,Crystallization ,0210 nano-technology ,Perovskite (structure) - Abstract
La2CuO4/LaFeO3 perovskite nanocomposites were prepared using a microwave combustion technique. The structural characterization by XRD and Rietveld refinements confirmed that Fe3+ substitution in La2CuO4 (LFC) induced the crystallization of secondary LaFeO3 phase. The orthorhombic/cubic nanostructured composites exhibited an average crystallite size in the range 37–47 nm and 14–39 nm, respectively. FTIR spectra revealed bands at 517, 683, and 561 cm−1, characteristics of perovskites orthorhombic and cubic stretching modes. With the increase in Fe3+ doping concentration, the optical band gap increased gradually. Surface morphology showed nanosized crystalline grains agglomerated with spherical and non-spherical shapes. The doping dependence of the magnetisation indicated magnetic transition from ferromagnetic to the paramagnetic state at room temperature. The bifunctional nanocomposites La2CuO4/LaFeO3 exhibited excellent catalytic performance and better conversion efficiency (conversion 100% and selectivity 98.6%) for glycerol.
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- 2019
21. Examining the associations between offending trajectories in adolescence/young adulthood and subsequent mental health disorders
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Joseph M. Boden, David M. Fergusson, L. John Horwood, and Grace H. Walker
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Sociology and Political Science ,Social Psychology ,050901 criminology ,05 social sciences ,medicine.disease ,Mental health ,Adult life ,medicine ,Anxiety ,0501 psychology and cognitive sciences ,0509 other social sciences ,Substance use ,medicine.symptom ,Young adult ,Psychology ,Law ,Applied Psychology ,Anxiety disorder ,Deviance (sociology) ,Depression (differential diagnoses) ,050104 developmental & child psychology ,Clinical psychology - Abstract
Purpose To examine associations between offending trajectory in adolescence/young adulthood and mental health outcomes in adulthood. Methods Data were used from the Christchurch Health and Development Study, a longitudinal birth cohort studied to age 35. Latent trajectory models were fitted to conduct problems and offending data from ages 8 to 21. Outcome measures included measures of DSM-IV major depression and anxiety disorders during the periods 21–25, 25–30, and 30–35 years. Associations between trajectory groups and mental health were adjusted for a series of childhood/adolescent sociodemographic, family functioning, and individual characteristics. In addition, the associations were adjusted for the mediating effects of life circumstances in adulthood, including substance use disorders, life stress, police contacts, and partner deviance. Results The bivariate associations showed clear linkages between offending and major depression and anxiety disorder in adulthood, which were reduced in magnitude following control for childhood and adolescent covariate factors. Finally, the analyses showed that these residual associations were largely mediated by adult life circumstances. Conclusions The results suggest that offending in adolescence/early adulthood is a risk marker for later mental health disorders, but that the causal role of offending in later mental health problems is likely to be relatively weak.
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- 2019
22. Alcohol and parenthood: An integrative analysis of the effects of transition to parenthood in three Australasian cohorts
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Elizabeth Spry, George C Patton, Craig A. Olsson, Margarita Moreno-Betancur, Edmund Silins, Joseph M. Boden, Denise Becker, George J. Youssef, Rohan Borschmann, Delyse Hutchinson, Richard P. Mattick, Louisa Degenhardt, Helena Romaniuk, Jake M. Najman, and L. John Horwood
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Adult ,Male ,Adolescent ,Alcohol Drinking ,Population Dynamics ,Population ,Binge drinking ,Alcohol abuse ,Toxicology ,Young Adult ,03 medical and health sciences ,0302 clinical medicine ,medicine ,Humans ,Pharmacology (medical) ,Prospective Studies ,030212 general & internal medicine ,education ,Prospective cohort study ,Pharmacology ,education.field_of_study ,Parenting ,business.industry ,Age Factors ,Australia ,Infant ,medicine.disease ,Substance abuse ,Alcoholism ,Psychiatry and Mental health ,Child, Preschool ,Relative risk ,Female ,business ,030217 neurology & neurosurgery ,Demography ,Cohort study ,Adolescent health - Abstract
Aims: To determine the extent to which the transition to parenthood protects against heavy and problematic alcohol consumption in young men and women. Design: Integrated participant-level data analysis from three population-based prospective Australasian cohort studies. Setting: General community; participants from the Australian Temperament Study, the Christchurch Health and Development Study, and the Victorian Adolescent Health Cohort Study. Measurements: Recent binge drinking, alcohol abuse/dependence and number of standard drinks consumed per occasion. Findings: 4015 participants (2151 females; 54%) were assessed on four occasions between ages 21 and 35. Compared to women with children aged
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- 2019
23. Structural, optical and magnetic properties of Zn1-xMnxFe2O4 (0 ≤ x ≤ 0.5) spinel nano particles for transesterification of used cooking oil
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L. John Kennedy, J. Judith Vijaya, and A. Ashok
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Materials science ,Diffuse reflectance infrared fourier transform ,Mechanical Engineering ,Spinel ,Metals and Alloys ,Analytical chemistry ,chemistry.chemical_element ,Infrared spectroscopy ,02 engineering and technology ,Transesterification ,Zinc ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Zinc ferrite ,chemistry ,Mechanics of Materials ,Biodiesel production ,Materials Chemistry ,engineering ,Fourier transform infrared spectroscopy ,0210 nano-technology - Abstract
Pure and manganese doped zinc ferrite nanoparticles were prepared via sonication assisted microwave irradiation method and it's employed for biodiesel production from used cooking oil (UCO). The nanoparticles were characterized by XRD, FTIR, DRS, HR-SEM, EDX and VSM techniques. The X-ray diffraction (XRD) results confirmed the formation of cubic spinel structure with Fd-3m space group without any impurities. The average crystalline size of manganese doped and undoped zinc ferrites were in the range from 7.49 nm to 9.65 nm as calculated from Scherer's formula. Fourier transformed infrared spectroscopy (FTIR) studies show the characteristic bands at 550 cm−1 and 419 cm−1 which confirming the presence of Fe-O and Zn-O vibrational stretching frequencies related to octahedral and tetrahedral positions of the zinc ferrite spinel's. UV–vis diffuse reflectance spectroscopy (DRS) revealed the optical energy band gap values in the range 1.90 eV–1.99 eV. The magnetic parameter such as coercivity (Hc), remanence magnetization (Mr) and saturation magnetization (Ms) were determined from hysteresis curves recorded at room temperature. The prepared ferrite nanoparticles were employed for the production of biodiesel from used cooking oil by transesterification process. The maximum yield of biodiesel 98.3% was achieved with 4 wt% of Mn2+ doped ZnFe2O4 nanocatalyst (ZnMnF5), reaction time 50 min, reaction temperature about 65 °C and methanol to oil molar ratio of 21:1. The ZnMnF5 sample was reused atleast 10 times with less reduction in activity. The standard values of biodiesel was measured using ASTM D-6751 method. The formation and composition of fatty acid methyl esters (FAME) were conformed using Gas chromatography-Mass spectroscopy. Mechanism for the biodiesel production using the doped zinc ferrite nanoparticle was proposed.
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- 2019
24. Catalytic studies of NiFe2O4 nanoparticles prepared by conventional and microwave combustion method
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K. Kombaiah, L. John Kennedy, J. Judith Vijaya, and K. Kaviyarasu
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Materials science ,Rietveld refinement ,Scanning electron microscope ,Nanoparticle ,02 engineering and technology ,Coercivity ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,law.invention ,Catalysis ,law ,General Materials Science ,Calcination ,Crystallite ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Nuclear chemistry - Abstract
A simple and rapid synthesis has been developed to synthesize NiFe2O4 nanoparticles with tunable optical, magnetic and catalytic properties by using Hibiscus rosa sinensis plant extract in the current study. The crystalline structure of the synthesized NiFe2O4 nanoparticles was confirmed by X-Ray diffraction (XRD) and Rietveld refinement analysis. Morphological, elemental, magnetic and optical properties of the synthesized nanoparticles were interpreted by fourier transform infra-red spectroscopy (FTIR), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX), UV–Visible diffused reflectance spectroscopy (UV-DRS), photoluminescence (PL) studies, and vibrating sample magnetometer (VSM). XRD analysis showed the single phase crystalline nature with average crystallite size of 50–70 nm. SEM and EDX analysis recognize the spherical shape nanoparticles and phase purity of the samples. The optical band gap is determined using UV-DRS spectra and is observed to decrease with increasing the calcination temperature. VSM studies obviously demonstrate the ferromagnetic property of the samples. The value of saturation magnetization has decreased with an increase in the calcination temperature and the coercivity is decreased. Additionally, NiFe2O4 nanoparticles were investigated for the catalytic reduction capability for different dyes like Rhodamine-B (Rh-B), Methylene blue (MB), Rose Bengal (RB), and Congo red (CR). It is found that the dye solution was degraded with increasing irradiation time. Hence, the prepared nanoparticles have been used as high potential catalysts for the reduction of organic dyes in the application of waste water treatment. NiFe2O4 is an active agent in catalyzing the oxidation of glycerol to formic acid with good conversion percentage and high selectivity. This catalytic system in the polar solvents, such as, acetonitrile provides the enhanced conversion results. The very important role played by a variety of reaction parameters in deciding the catalytic effectiveness is well established and every parameter has an optimal value to acquire the maximum catalytic activity.
- Published
- 2019
25. Synthesis, structure, NBO, Hirshfeld surface, NMR, HOMO-LUMO, UV, photoluminescence, z scan, vibrational and thermal analysis of piperazinedi-ium tetrakis (μ2‑chloro)-diaqua-dichloro-di-cadmium single crystal
- Author
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Nimmy L. John, Sunila Abraham, Jesby George, P. Karuppasamy, M. Senthilpandian, P. Ramasamy, and G. Vinitha
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Inorganic Chemistry ,Organic Chemistry ,Spectroscopy ,Analytical Chemistry - Published
- 2022
26. Facile microwave assisted combustion synthesis, structural, optical and magnetic properties of La2−Sr CuO4 (0 ≤ x ≤ 0.5) perovskite nanostructures
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J. Judith Vijaya, L. John Kennedy, Mohamed Bououdina, B. Al-Najar, and M. Sukumar
- Subjects
Materials science ,Photoluminescence ,Diffuse reflectance infrared fourier transform ,Scanning electron microscope ,Analytical chemistry ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Electronic, Optical and Magnetic Materials ,Tetragonal crystal system ,Orthorhombic crystal system ,Crystallite ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Perovskite (structure) - Abstract
Strontium doped lanthanum cuprate perovskite-type nanostructures were synthesized by facile microwave assisted combustion method. The structural, optical, morphological, and magnetic properties were studied by using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX), photoluminescence (PL) and vibrating sample magnetometer (VSM) techniques.The XRD patterns of pure La 2 CuO 4 (LC) and La 1.9 Sr 0.1 CuO 4 confirmed the formation of perovskite structure without impurities. However with the increase in Sr 2+ content from ( x = 0.2–0.5), phase transformation from orthorhombic to tetragonal structure, occurred. The average crystallite size of orthorhombic and tetragonal phases were in the range 39.6–47.4 nm and 22.3–88.0 nm, respectively. The presence of tensile strain in Sr 2+ doped LC (LSC) was determined from Williamson–Hall (W–H) analysis. The appearance of FT-IR bands at around 688 and 521 cm -1 were correlated to the La-O and Cu-O stretching modes of orthorhombic La 2 CuO 4 phase. The direct band gap estimated using Kubelka–Munk (K–M) method increased with increasing Sr 2+ content (1.88–2.03 eV), due to quantum confinement. For LC and LSC, PL spectra showed emission bands in UV and visible regions, due to the defect centers acting as trap levels. The LSC system showed the formation of nanosized crystallized grains with pores and pore-walls due to fused grains. Magnetization–Field (M−H) hysteresis curves revealed the appearance of ferro-/para- magnetic behavior at room temperature.
- Published
- 2018
27. Synergic effect of Cu2O/MoS2/rGO for the sonophotocatalytic degradation of tetracycline and ciprofloxacin antibiotics
- Author
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Selvamani, P. Stephen, primary, Vijaya, J. Judith, additional, Kennedy, L. John, additional, Mustafa, A., additional, Bououdina, M., additional, Sophia, P. Joice, additional, and Ramalingam, R. Jothi, additional
- Published
- 2021
- Full Text
- View/download PDF
28. Mild COVID-19 infection despite chronic B cell depletion in a patient with aquaporin-4-positive neuromyelitis optica spectrum disorder
- Author
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Jaime Imitola, Enrique Ballesteros, Marina A. Creed, and L. John Greenfield
- Subjects
Multiple Sclerosis ,coronaviruses ,Clinical Neurology ,Disease ,Neuromyelitis Optica Spectrum Disorder (NMOSD) ,medicine.disease_cause ,Article ,03 medical and health sciences ,0302 clinical medicine ,Medicine ,Humans ,Immunologic Factors ,030212 general & internal medicine ,Coronavirus ,Autoantibodies ,Aquaporin 4 ,B-Lymphocytes ,Neuromyelitis optica ,SARS-CoV-2 ,business.industry ,pandemic ,Multiple sclerosis ,Neuromyelitis Optica ,COVID-19 ,General Medicine ,Middle Aged ,medicine.disease ,Pneumonia ,Neurology ,Immunology ,Rituximab ,Female ,Neurology (clinical) ,business ,Cytokine storm ,030217 neurology & neurosurgery ,medicine.drug - Abstract
Coronavirus disease 2019 (COVID-19) is caused by the novel coronavirus SARS-CoV-2, which affects the lung and other organs. After an incubation period of 3-14 days, the infection presents with symptoms of variable severity, from mild flu-like disease to severe pneumonia and cytokine storm with increased mortality. Immunosuppressed patients may have higher risk of adverse outcomes; hence, there is an urgent need to evaluate the immune response and clinical outcomes of SARS-CoV-2 infection in these patients. Here, we report a 59-year-old woman with aquaporin-4-positive (AQPR4+) neuromyelitis Optica treated with rituximab who developed mild respiratory symptoms with COVID-19, despite B cell depletion at the time of infection.
- Published
- 2020
- Full Text
- View/download PDF
29. Structural, magnetic and catalytic properties of La2-Ba CuO4 (0 ≤ x ≤ 0.5) perovskite nanoparticles
- Author
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B. Al-Najar, J. Judith Vijaya, L. John Kennedy, Mohamed Bououdina, and M. Sukumar
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Materials science ,Diffuse reflectance infrared fourier transform ,Band gap ,Process Chemistry and Technology ,Analytical chemistry ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,0104 chemical sciences ,Surfaces, Coatings and Films ,Electronic, Optical and Magnetic Materials ,Tetragonal crystal system ,Materials Chemistry ,Ceramics and Composites ,Direct and indirect band gaps ,Orthorhombic crystal system ,Crystallite ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Perovskite (structure) - Abstract
Barium doped La 2 CuO 4 perovskite nanoparticles were synthesized via microwave assisted combustion method. The effects of Ba 2+ doping on structural, optical, magnetic and catalytic activity of La 2 CuO 4 have been studied by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), diffuse reflectance spectroscopy (DRS), scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDX) and vibrating sample magnetometer (VSM) techniques. The XRD patterns of pure La 2 CuO 4 and La 1.9 Ba 0.1 CuO 4 confirmed the formation of perovskite structure without impurities. However, with increasing Ba 2+ content in the range 0.2–0.5, phase transformation from orthorhombic to tetragonal structure, occurred. The average crystallite size of orthorhombic and tetragonal phases were in the range 45.2–52.2 nm and 0.5–41 nm, respectively. The appearance of FT-IR bands at around 685 and 517 cm −1 were correlated to the La-O and Cu-O stretching modes of orthorhombic La 2 CuO 4 phase. The direct band gap estimated using Kubelka–Munk (K–M) method decreased with the increase in Ba 2+ content (1.88–1.64 eV), due to the formation of sub-bands in the energy band gap. Magnetic measurements of doped La 2 CuO 4 samples showed either para- or ferro-/para- magnetic behaviour at room temperature. The catalytic activity (oxidation) tests carried out in a batch reactor operating under atmospheric conditions indicated that the prepared catalysts, in particular (La 1.7 Ba 0.3 CuO 4 ), showed excellent catalytic activity.
- Published
- 2018
30. Value added porous carbon from leather wastes as potential supercapacitor electrode using neutral electrolyte
- Author
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L. John Kennedy, T. Ratnaji, J. Judith Vijaya, and Niketha Konikkara
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Supercapacitor ,Materials science ,Municipal solid waste ,Renewable Energy, Sustainability and the Environment ,020209 energy ,Strategy and Management ,chemistry.chemical_element ,02 engineering and technology ,Electrolyte ,021001 nanoscience & nanotechnology ,Industrial and Manufacturing Engineering ,Dielectric spectroscopy ,Chromium ,Chemical engineering ,chemistry ,0202 electrical engineering, electronic engineering, information engineering ,Specific energy ,Cyclic voltammetry ,0210 nano-technology ,Carbon ,General Environmental Science - Abstract
Leather industries produce a large quantity of chromium containing wet blue leather solid waste (WBW), that are either thrown away or dumped in open lands causing environmental issues. These WBW are biologically resistant as a result of complexation between chromium (III) salts and the carboxyl groups of collagen. The objective of this study is to propose an unusual way to minimize environmental contamination routing through waste to energy concept, adopting cleaner methodologies. The research is also specifically focussed to bring in, new initiatives through interdisciplinary approach serving as a decisive key to transform wet blue leather wastes into a high performance supercapacitor electrode material. Electrochemical measurements such as cyclic voltammetry, galvanostatic charge discharge, and electrochemical impedance spectroscopy techniques using 1 M Na2SO4 aqueous electrolyte were performed to evaluate the suitability of the prepared carbon for supercapacitor applications. Na2SO4, is chosen as it can serve as neutral electrolyte, and has less corrosion behavior. The values of specific capacitance, specific energy, specific power and cycle stability for WBW activated at 900 °C (LSAC9) were 2203 Fg-1, 624.7 Whkg−1, 749.9 Wkg-1 and over 10,000 cycles respectively and are comparable with graphene like carbons. The performance of WBW porous carbons are consequence of micro-meso porosity and graphitic structure and are an initiative of waste to energy storage conversion concepts.
- Published
- 2018
31. In-vitro anti-cancer activity of organic template-free hierarchical M (Cu, Ni)-modified ZSM-5 zeolites synthesized using silica source waste material
- Author
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K. Kaviyarasu, P. Iyyappa Rajan, L. John Kennedy, J. Judith Vijaya, S. K. Jesudoss, and S. Narayanan
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Thermogravimetric analysis ,Biophysics ,Antineoplastic Agents ,Apoptosis ,02 engineering and technology ,010402 general chemistry ,01 natural sciences ,Metal ,Adsorption ,Microscopy, Electron, Transmission ,X-Ray Diffraction ,Nickel ,Desorption ,Spectroscopy, Fourier Transform Infrared ,Humans ,Radiology, Nuclear Medicine and imaging ,MTT assay ,Fourier transform infrared spectroscopy ,High-resolution transmission electron microscopy ,Radiation ,Radiological and Ultrasound Technology ,Chemistry ,Oryza ,Silicon Dioxide ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,Oxidative Stress ,A549 Cells ,visual_art ,Microscopy, Electron, Scanning ,Zeolites ,visual_art.visual_art_medium ,Nanoparticles ,ZSM-5 ,0210 nano-technology ,Copper ,DNA Damage ,Nuclear chemistry - Abstract
The present paper is focused on a simple and economical route to synthesize the organic template-free hierarchical pure and M (Cu, Ni)-modified ZSM-5 zeolites (1%, 3% and 5%) using hydrothermal treatment in the presence of silica rich rice husk ash and its application studies through the evaluation of their anti-cancer activity on A459 human lung epithelial cancer cell lines. The physical properties of the samples were characterized by X-ray diffraction, Fourier transform infrared spectroscopy, high resolution scanning electron microscopy, high resolution transmission electron microscopy, N2 adsorption/desorption techniques and thermogravimetric analysis respectively. These metals modified hierarchical ZSM-5 zeolites showed considerable in-vitro anticancer efficiency towards human lung cancer (A549) cell lines through (3-(4, 5-dimethyl thiazolyl)-2, 5-diphenyl tetrazolium bromide) MTT assay. Among the all M (Cu, Ni)-modified ZSM-5 zeolites, 5% Cu-ZSM-5 zeolites showed higher potential cytotoxicity against A459 cell lines. The possible mechanism was explored from the fundamental signaling pathways of cell death by hierarchical metal modified ZSM-5 zeolites in A459 human lung epithelial cancer cell lines. Finally, our experimental results revealed that the organic template-free hierarchical pure and M (Cu, Ni)-modified ZSM-5 zeolites have significant anti-cancer mediating action by inducing oxidative stress to intercede DNA damage and can be considered as a potential applicant in the biomedical field.
- Published
- 2018
32. Synthesis of MoS2 nanoparticle deposited graphene/mesoporous MnOx nanocomposite for high performance super capacitor application
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Shaban R.M. Sayed, S. K. Khadheer Basha, R. Jothi Ramalingam, L. John Kennedy, Dhaifallah Al-Dhayan, Niketha Konikkara, and Hamad A. Al-Lohedan
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Supercapacitor ,Nanocomposite ,Materials science ,Renewable Energy, Sustainability and the Environment ,Graphene ,Oxide ,Energy Engineering and Power Technology ,Nanoparticle ,chemistry.chemical_element ,02 engineering and technology ,Substrate (electronics) ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,law.invention ,chemistry.chemical_compound ,Fuel Technology ,chemistry ,Chemical engineering ,law ,Molybdenum ,0210 nano-technology ,Mesoporous material - Abstract
The present study deal with the fabrication of low cost nanocomposite based electrodes based on Nickel foam binder free substrate for supercapacitor applications. The composition of nanocomposite is molybdenum sulphide nanoparticle/graphene coated on mesoporous manganese oxide. The first step is to involve the preparation of mesoporous manganese oxide by non-ionic surfactant assisted method. In the second stage is to deposit the reduced graphene on mesoporous manganese oxide in the presence of ultrasonic irradiation followed by addition of known quantity of commercial MoS2 nanopowder (particle size below 90 nm). The manganese oxide based nanocomposite is showing porous architecture with graphene sheet formation together with MoS2 nanoparticle deposition. N2 adsorption-desorption Isotherm curves for MoS2 nanoparticle (NP) modified graphene oxide/meso-MnO2 and pure meso-MnO2 displayed type IV isotherm with improved surface area values. The reduced graphene oxide (graphene) and MoS2 exist in the form of glassy flaky morphology as well as tubular/needle shapes are obtained after the deposition process in the final nanocomposite. The orderly arranged and anchored nano-sized mesoporous manganese oxide nanocomposites are showed increased specific capacitance (up to 527, 727 and 1160 F/g) and continuous cyclic stability.
- Published
- 2018
33. Effect of zinc precursors on the hydrogen evolution reaction and electrochemical corrosion studies of ZnWO 4 nanoparticles synthesized by hot injection method
- Author
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P. Rupa Kasturi, A. Shanmugavani, L. John Berchmans, S. Gowrimeena, Subramanian Yuvaraj, and R. Kalai Selvan
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Tafel equation ,Materials science ,chemistry.chemical_element ,Nanoparticle ,02 engineering and technology ,General Chemistry ,Zinc ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Zinc nitrate ,General Materials Science ,Sodium tungstate ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Thermal analysis ,Monoclinic crystal system ,Nuclear chemistry - Abstract
ZnWO 4 nanoparticles were synthesized by a hot injection method using different zinc precursors (zinc nitrate, zinc acetate, zinc sulphate and zinc chloride) with sodium tungstate. Similarly, the ZnWO 4 particles were prepared by co-precipitation and solid-state method for comparative analysis. The phase formation temperature of ZnWO 4 was identified through thermal analysis. X-Ray diffraction (XRD) analysis enumerates that the formation of a single-phase monoclinic wolframite structure with the space group P2/c. The characteristic functional groups of Zn-O, Zn-O-W, and W-O were identified through Fourier Transform Infrared Spectroscopy (FTIR). The microscopic images revealed that the formation of spherical shape particles in size range between 60 and 100 nm. The room temperature electrical conductivity was measured using LCR meter, and it shows that the conductivity is in the range of 2.2 × 10 −5 to 6.2 × 10 −6 S.cm −1 . The calculated corrosion rate of ZnWO 4 using Tafel Polarization curve in 1 M H 2 SO 4 at 1 mV s −1 was 0.2554 mmpy. The electrocatalytic activity towards the hydrogen evolution reaction (HER) was studied using linear sweep voltammogram in 1 M H 2 SO 4 solution at a scan rate of 1 mV s −1 . Further, the zinc acetate precursor assisted particles have shown a low onset potential (0.42 V) and higher current density (−228.52 mA cm −2 ) in the potential range of 0 to −1.0 V compared with other samples.
- Published
- 2018
34. Carbon nanotube mediated miscibility of polyhydroxyalkanoate blends and chemical imaging using deuterium-labelled poly(3-hydroxyoctanoate)
- Author
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Peter J. Holden, L. John R. Foster, and Robert A. Russell
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Materials science ,Polymers and Plastics ,General Physics and Astronomy ,Nanoparticle ,02 engineering and technology ,Carbon nanotube ,engineering.material ,010402 general chemistry ,01 natural sciences ,Miscibility ,law.invention ,law ,Materials Chemistry ,chemistry.chemical_classification ,Nanocomposite ,Organic Chemistry ,Percolation threshold ,Polymer ,021001 nanoscience & nanotechnology ,0104 chemical sciences ,chemistry ,Chemical engineering ,engineering ,Polymer blend ,Biopolymer ,0210 nano-technology - Abstract
Biopolymers have potential as scaffolds supporting regrowth of damaged tissues, however their material properties may limit the range of applications. Blending polymers with different thermomechanical properties has been demonstrated to extend the range of possible applications for polyhydroxyalkanoate (PHA) polymers, while the addition of nanoparticles can be used to modulate miscibility which influences strength and flexibility of the blend. Here we report on the blending of Poly(3-hydroxybutyrate) and Poly(3-hydroxyoctanoate) which possess different thermomechanical properties, and the effect of single wall carbon nanotubes (SWCNT) on their miscibility, electrical conductivity and thermomechanical performance. The apparent perturbation of phase boundaries in nanocomposite films observed by Scanning Electron Microscopy (SEM) was complemented by chemical mapping of film cross sections containing a deuterium-labelled poly(3-hydroxyoctanoate) phase in the blend using Infrared Microspectroscopy (IRM), suggesting increased miscibility due to nanoparticle addition. The electrical percolation threshold in nanocomposite films was observed between 0.5 and 1 wt% SWCNT, where the surface resistivity was reduced by eight orders of magnitude compared to the insulating polymer blend. Addition of SWCNT did not impact significantly on mechanical properties of films containing up to 2.5 wt% SWCNT. A solvent cast bionanocomposite film containing optimally 1 wt% SWCNT yielded a material with improved electrical conductivity compared to the SWCNT-free blend and which supported growth of Olfactory Ensheathing Cells, providing a basis for developing biopolymer scaffolds capable of conducting electrical stimulation.
- Published
- 2018
35. Conventional and microwave combustion synthesis of optomagnetic CuFe2O4 nanoparticles for hyperthermia studies
- Author
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B. Al-Najar, J. Judith Vijaya, M. Bououdina, L. John Kennedy, and K. Kombaiah
- Subjects
Materials science ,Rietveld refinement ,Analytical chemistry ,Nanoparticle ,02 engineering and technology ,General Chemistry ,Coercivity ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,law.invention ,Magnetic hyperthermia ,law ,Ferrite (magnet) ,General Materials Science ,Calcination ,Particle size ,Crystallite ,0210 nano-technology - Abstract
Nanosized copper ferrite (CuFe2O4) nanoparticles have been prepared by conventional (CCM) and microwave (MCM) combustion methods using Hibiscus rosa sinensis plant extract as a fuel. XRD and rietveld analysis confirmed the formation of single cubic phase and with crystallite size varying from 25 to 62 nm owing to grain growth after calcination. FT-IR analysis confirms the modes of the cubic CuFe2O4 phase, due to the stretching and bending vibrations. Spherical shaped particles are observed by scanning electron microscopy and the average particle size is found to be in the range of 50–200 nm. The chemical composition is confirmed by energy dispersive X-ray analysis. The optical band gap energy estimated using Kubelka-Munk function with the help of UV–Visible diffused reflectance spectroscopy, is found to be 2.34 and 2.22 eV for CCM and MCM respectively. Photoluminescence analysis indicates that both samples absorb light in the UV–visible region and exhibit emissions at 360, 376, and 412 nm. Magnetic measurements indicate a ferromagnetic behavior, where both magnetic properties very much influenced by the preparation method and calcination temperature: both saturation magnetization and coercivity are found higher when using CCM and MCM; from 29.40 to 34.09 emu/g while almost double from 224.4 to 432.2 Oe. The observed changes in physical properties are mainly associated with crystallinity, particle size, better chemical homogeneity, and cations distribution among tetrahedral/octahedral sites. The maximum specific absorption rate obtained was 14.63 W/g, which can be considered suitable and favorable for magnetic hyperthermia. This study highlighted the benefits of green synthesis of CuFe2O4 nanoparticles providing better magnetic properties for the platform of hyperthermia application.
- Published
- 2018
36. Self heating efficiency of CoFe2O4 nanoparticles: A comparative investigation on the conventional and microwave combustion method
- Author
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K. Kombaiah, L. John Kennedy, Basma Al Najar, M. Bououdina, and J. Judith Vijaya
- Subjects
010302 applied physics ,Materials science ,Diffuse reflectance infrared fourier transform ,Band gap ,Mechanical Engineering ,Metals and Alloys ,Analytical chemistry ,02 engineering and technology ,Coercivity ,021001 nanoscience & nanotechnology ,Combustion ,01 natural sciences ,Mechanics of Materials ,0103 physical sciences ,Materials Chemistry ,Magnetic nanoparticles ,Particle size ,Crystallite ,0210 nano-technology ,Microwave - Abstract
In the present study, we have focused on opuntia dilenii haw mediated green synthesis of cobalt ferrite (CoFe2O4) nanoparticles through microwave combustion method (MCM) and it is further compared with the conventional combustion method (CCM). The effect on structural, morphological, optical and magnetic properties of the synthesized nanoparticles was investigated systematically. In addition, the efficiency of self heating measurements was investigated for hyperthermia applications. X-ray diffraction studies confirmed the formation of single phase crystalline nature of CoFe2O4 nanoparticles. The crystallite size of 58 nm and 49 nm is obtained for CCM and MCM respectively. The functional groups occurred at 597 cm−1, 599 cm−1, 427 cm−1 and 437 cm−1 that corresponds to Fe-O and Co-O bands at tetrahedral and octahedral sites are analyzed by FT-IR studies. Scanning electron microscopy images of the samples revealed the morphology as spherical with the average particle size range of 40–200 nm. The existence of Co, Fe, O present in the sample is confirmed by EDX analysis which shows the purity of the samples. UV–Visible diffuse reflectance spectroscopy is used to analyze the optical band gap energy of the samples estimated from Kubelka-Munk function as 2.01 eV, 1.93 eV for CCM and MCM respectively. The structural defects present in the samples are investigated by photoluminescence studies and the samples emit the light at two different wavelengths of 494 nm, and 621 nm. Vibrating sample magnetometer is carried out to analyze the magnetic properties of the samples at room temperature. The saturation magnetization of the CoFe2O4 nanoparticles is found to be 77.29 emu/g and 68.76 emu/g for MCM and CCM respectively. The results obtained in this work suggested that the value of crystallite size, particle size, band gap value, luminescence intensities, and coercivity values increases with an increase in calcination temperature in conventional combustion method. Specific absorption rate (SAR) increases with a decrease in the crystallite size and particle size in microwave combustion method. The gradual increase in SAR is due to the hysteresis loss that occurs because of the ferromagnetic nature obtained by the microwave combustion method. An overview of the present work gives a summary on the green synthesis of magnetic nanoparticles, which provides comprehensive evaluation of hyperthermia through self heating process. Finally, from our results, the SAR obtained by microwave combustion method has higher efficiency compared to the conventional combustion method.
- Published
- 2018
37. Okra extract-assisted green synthesis of CoFe2O4 nanoparticles and their optical, magnetic, and antimicrobial properties
- Author
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K. Kombaiah, J. Judith Vijaya, L. John Kennedy, R. Jothi Ramalingam, Hamad A. Al-Lohedan, and M. Bououdina
- Subjects
Photoluminescence ,Materials science ,Band gap ,Analytical chemistry ,Nanoparticle ,chemistry.chemical_element ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,Crystallinity ,chemistry ,General Materials Science ,Fourier transform infrared spectroscopy ,0210 nano-technology ,Spectroscopy ,Cobalt ,Microwave ,Nuclear chemistry - Abstract
Cobalt ferrite nanoparticles are synthesized using biological agents as fuel by both conventional and microwave heating methods. We focused on the green synthesis of cobalt ferrite, which is eco friendly, inexpensive, and easy to produce by large-scale synthesis. Synthesis methods were carried out under the same conditions. The role of the plant extract and advantages of microwave techniques are discussed. Plant extract-mediated nanoparticles were characterized by various techniques to analyze the size, shape, crystallinity, optical, magnetic, and antimicrobial properties. The X-ray diffraction pattern revealed single-phase crystalline structures with an average size of 45–55 nm. The functional groups present in the samples were confirmed by Fourier transform infrared spectroscopy. From SEM and DLS studies, it is confirmed that the spherical nanoparticles range in the size of 300–500 nm for CHM and 5–50 nm for MHM. Energy-dispersive X-ray spectroscopy analysis confirmed the presence of cobalt, iron, and oxygen. The energy band gap of the samples was measured by UV–Visible diffuse reflection spectroscopy. In photoluminescence analysis, the band emission was observed in the visible region. Samples prepared by microwave heating showed better magnetic behavior than those prepared by conventional heating based on vibrating sample magnetometer analysis. The plant extract makes the synthesis of cobalt ferrite nanoparticles a potentially low-cost and ecofriendly remediation method. The synthesized nanoparticles also exhibited excellent antimicrobial activity against bacteria and fungus strains.
- Published
- 2018
38. Bioreduction potentials of dried root of Zingiber officinale for a simple green synthesis of silver nanoparticles: Antibacterial studies
- Author
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L. John Kennedy, K. Kaviyarasu, Malik Maaza, Hamad A. Al-Lohedan, R. Jothi Ramalingam, J. Judith Vijaya, N. Jayaprakash, K. Kombaiah, and V M Mansoor-Ali
- Subjects
Silver ,Scanning electron microscope ,education ,Biophysics ,Analytical chemistry ,Metal Nanoparticles ,02 engineering and technology ,Ginger ,010402 general chemistry ,Plant Roots ,01 natural sciences ,Silver nanoparticle ,Crystallinity ,Microscopy, Electron, Transmission ,X-Ray Diffraction ,Gram-Negative Bacteria ,Spectroscopy, Fourier Transform Infrared ,Radiology, Nuclear Medicine and imaging ,Particle Size ,Radiation ,Radiological and Ultrasound Technology ,Plant Extracts ,Chemistry ,Spectrometry, X-Ray Emission ,Green Chemistry Technology ,Electrochemical Techniques ,021001 nanoscience & nanotechnology ,Anti-Bacterial Agents ,0104 chemical sciences ,Transmission electron microscopy ,Microscopy, Electron, Scanning ,Crystallite ,Selected area diffraction ,Cyclic voltammetry ,0210 nano-technology ,Antibacterial activity ,Nuclear chemistry - Abstract
Green synthesis of silver nanoparticles (Ag NPs) using an extract of dried Zingiber officinale (ginger) root as a reducing and capping agent in the presence of microwave irradiation was herein reported for the first time. The formation of symmetrical spheres is confirmed from the UV-Visible spectrum of Ag NPs. Fourier transform infra-red spectroscopy confirms the formation of the Ag NPs. X-ray diffraction analysis was utilized to calculate the crystallite size of Ag NPs and the value was found to be 10nm. High-resolution transmission electron microscopy and high-resolution scanning electron microscopy were used to investigate the morphology and size of the synthesized samples. The sphere like morphology is confirmed from the images. The purity and crystallinity of Ag NPs is confirmed by energy-dispersive X-Ray analysis and selected area electron diffraction respectively. The electrochemical behavior of the synthesized Ag NPs was assessed by cyclic voltammetry (CV) and shows the redox peaks in the potential range of -1.1 to +1.1V. Agar diffusion method is used to examine the antibacterial activity of Ag NPs. For this purpose, two gram positive and two gram negative bacteria were studied. This single step approach was found to be simple, short time, cost-effective, reproducible, and eco-friendly.
- Published
- 2017
39. Hierarchical porous carbon derived from tea waste for energy storage applications: Waste to worth
- Author
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Ratnaji, T., primary and Kennedy, L. John, additional
- Published
- 2020
- Full Text
- View/download PDF
40. Facile microwave synthesis of cerium oxide@molybdenum di-sulphide@reduced graphene oxide ternary composites as high performance supercapacitor electrode
- Author
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P. Joice Sophia, B. Saravanakumar, J. Judith Vijaya, P. Stephen Selvamani, L. John Kennedy, and N. Clament Sagaya Selvam
- Subjects
Supercapacitor ,Cerium oxide ,Graphene ,General Chemical Engineering ,Oxide ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,01 natural sciences ,Capacitance ,Energy storage ,0104 chemical sciences ,Analytical Chemistry ,law.invention ,chemistry.chemical_compound ,chemistry ,law ,Electrode ,Electrochemistry ,Composite material ,0210 nano-technology ,Ternary operation - Abstract
There is a huge requirement for renewable energy resources to avoid the usage of fossil fuel attracted the researchers to work on the energy storage devices, such as supercapacitors. Herein, the novel synthesis of CeO2@MoS2@rGO (CeMG) ternary composite by two step microwave synthetic route that will be employed as an outstanding electrode material for supercapacitor. In particular, the morphology studies confirm that the cerium oxide has spherical morphology with the controlled size in the range of 12–15 nm embedded with the layered sheets of MoS2 and reduced graphene oxide. The CeMG composites exhibit excellent specific capacitance of 635 F g−1 which is achieved at the current density of 1 A g−1 compared to the pure CeO2. In addition, prolonged cyclic stability with 88.9% capacitance is retained after 10,000 cycles of charging and discharging.
- Published
- 2021
41. Design of copper (II) oxide nanoflakes decorated with molybdenum disulfide@reduced graphene oxide composite as an electrode for high performance supercapacitor
- Author
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P. Stephen Selvamani, B. Saravanakumar, Jothi Ramalingam Rajabathar, Mohamed Bououdina, L. John Kennedy, and J. Judith Vijaya
- Subjects
Supercapacitor ,Nanostructure ,Materials science ,Nanocomposite ,Graphene ,Mechanical Engineering ,Metals and Alloys ,Electrolyte ,Condensed Matter Physics ,Electronic, Optical and Magnetic Materials ,Copper(II) oxide ,law.invention ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Mechanics of Materials ,law ,Electrode ,Materials Chemistry ,Molybdenum disulfide - Abstract
A simple and cost-efficient microwave route has been adopted to synthesize CuO/MoS2/rGO (CuMG) nanostructure as a potential electrode for supercapacitor. The morphological investigation indicates that the nanoflakes of bare CuO are decorated with the layered MoS2/rGO nanostructures. CuMG composite exhibits a higher specific capacitance of 1445 F g−1 @1 A g−1 compared to 535 F g−1 @1 A g−1 for CuO. This result demonstrates that the addition of MoS2/rGO to CuO initiates the rapid migration of electrolyte ions. Moreover, this interesting nanocomposite possesses good cyclic stability; i.e. only 9.1% loss after 3000 charge-discharge cycles at the high-applied current of 30 A g−1. The excellent electrochemical properties of CuMG extend its usage as high performance electrode materials in next-generation energy storage applications.
- Published
- 2021
42. P225 Parents’ feedback on virtual paediatric cystic fibrosis clinics during COVID-19 pandemic
- Author
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L. John, R. Rees, R. Street, M. Powell, and R. Evans
- Subjects
Pulmonary and Respiratory Medicine ,2019-20 coronavirus outbreak ,medicine.diagnostic_test ,Coronavirus disease 2019 (COVID-19) ,business.industry ,Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) ,Physical examination ,medicine.disease ,Cystic fibrosis ,Pediatrics, Perinatology and Child Health ,Pandemic ,medicine ,Medical emergency ,Health board ,business ,Lung function - Abstract
Introduction: The COVID-19 pandemic led to cancellation of all face-to-face clinics in our health board in mid-March 2020. Overnight we had to develop an alternative service for our cystic fibrosis children. We set up video clinics from end of March 2020 using Webex initially and then Attend Anywhere when this became available in July 2020. We also arranged supplies of rescue antibiotics at home and arranged to collect cough swabs from patients’ doorsteps. Objectives: To obtain feedback from parents on the cystic fibrosis service provided during COVID-19 pandemic, including virtual clinics, and to get their opinion about use of virtual cystic fibrosis clinics post COVID-19. Methods: Short questionnaire was devised and e-mailed to parents in January 2021. Results: 23 of 26 questionnaires have been returned to date. 100% were very satisfied with service provided during the COVID-19 pandemic and 78%were very satisfied, with 17% satisfied with use of virtual consultations. Mean score for ease of use of Attend Anywhere was 9.4 out of 10. 74% were very satisfied and 22% satisfied that their needs were met via virtual consultations. 39% were very satisfied, 35% satisfied with alternate virtual and face-to-face clinic appointments post-COVID-19. Concerns were raised around no clinical examination and delays in replacing physiotherapy equipment with virtual appointments. Areas suggested for improvement included the ability to do lung function at home. Conclusion: Parents were supportive of the use of virtual clinics during COVID-19 but there were mixed views with continuing virtual clinics post-COVID-19.
- Published
- 2021
43. Green synthesis of nickel oxide nanoparticles using Solanum trilobatum extract for cytotoxicity, antibacterial and photocatalytic studies
- Author
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Ezhilarasi, A. Angel, primary, Vijaya, J. Judith, additional, Kaviyarasu, K., additional, Zhang, Xu, additional, and Kennedy, L. John, additional
- Published
- 2020
- Full Text
- View/download PDF
44. High-performance supercapacitor based on Cu2O/MoS2/rGO nanocomposite
- Author
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Selvamani, P. Stephen, primary, Vijaya, J. Judith, additional, Kennedy, L. John, additional, Saravanakumar, B., additional, and Bououdina, M., additional
- Published
- 2020
- Full Text
- View/download PDF
45. Mild COVID-19 infection despite chronic B cell depletion in a patient with aquaporin-4-positive neuromyelitis optica spectrum disorder.
- Author
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Creed, Marina A., primary, Ballesteros, Enrique, additional, Jr, L. John Greenfield, additional, and Imitola, Jaime, additional
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- 2020
- Full Text
- View/download PDF
46. A simple self-assembly fabrication of tin oxide nanoplates on multiwall carbon nanotubes for selective and sensitive electrochemical determination of antipyretic drug
- Author
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Keerthika Devi, R., primary, Muthusankar, G., additional, Gopu, G., additional, and Berchmans, L. John, additional
- Published
- 2020
- Full Text
- View/download PDF
47. Green mediated NiO nano-rods using Phoenix dactylifera (Dates) extract for biomedical and environmental applications
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Ezhilarasi, A. Angel, primary, Vijaya, J. Judith, additional, Kennedy, L. John, additional, and Kaviyarasu, K., additional
- Published
- 2020
- Full Text
- View/download PDF
48. Microwave synthesized α-Fe2O3/MoS2/rGO composites as high-performance supercapacitor
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P. Stephen Selvamani, B. Saravanakumar, L. John Kennedy, J. Judith Vijaya, and Mohamed Bououdina
- Subjects
Supercapacitor ,Materials science ,Mechanical Engineering ,Composite number ,Nanoparticle ,02 engineering and technology ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electrochemistry ,01 natural sciences ,Capacitance ,Energy storage ,0104 chemical sciences ,Mechanics of Materials ,General Materials Science ,Composite material ,0210 nano-technology ,Current density ,Microwave - Abstract
Cost-efficient microwave synthesisized α-Fe2O3/MoS2/rGO (Fe2MG) composite has been fabricated with promising energy storage characteristics. SEM and TEM analyses corroborate that the spherical α-Fe2O3 nanoparticles are wrapped over MoS2 and rGO sheets. The Fe2MG composite electrode exhibits high specific capacitance of 551 F.g−1 at 1 A.g−1 and improved cyclic stability with only 2.1% of capacitance loss after 2000 charge–discharge cycles at a high current density (30 mA.s−1). The Fe2MG composite is a suitable choice as an electrode material for supercapacitor and other electrochemical applications.
- Published
- 2021
49. Electrochemical properties of solid leather wastes based supercapacitor electrodes using H2SO4 electrolyte
- Author
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Niketha Konikkara and L. John Kennedy
- Subjects
Supercapacitor ,Materials science ,Mechanical Engineering ,02 engineering and technology ,Electrolyte ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Electrochemistry ,01 natural sciences ,Capacitance ,0104 chemical sciences ,Dielectric spectroscopy ,Chemical engineering ,Mechanics of Materials ,Electrode ,General Materials Science ,Cyclic voltammetry ,0210 nano-technology ,Porous medium - Abstract
Solid leather wastes (SLW) based porous carbons were used as the electrode material for supercapacitors in acid (H2SO4) medium. Electrochemical investigations indicate that samples activated at 900 °C shows a maximum capacitance of 1833 F/g at a scan rate of 1 mV/s in 1 M H2SO4 electrolyte. Moreover, SLW porous carbon electrodes show excellent cycling stability over 500 cycles at a constant current density of 20 A/g. Cyclic voltammetry (CV), galvanostatic charge/discharge (GCD) and electrochemical impedance spectroscopy (EIS) studies propose porous carbons developed from SLW could be an excellent electrode material for supercapacitors even in strong acid electrolyte medium.
- Published
- 2017
50. Visible light driven photocatalytic degradation of rhodamine B using Mg doped cobalt ferrite spinel nanoparticles synthesized by microwave combustion method
- Author
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L. John Kennedy, M. Bououdina, P. Nithya, J. Judith Vijaya, and M. Sundararajan
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Materials science ,Scanning electron microscope ,Spinel ,Analytical chemistry ,Mineralogy ,02 engineering and technology ,General Chemistry ,engineering.material ,010402 general chemistry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,01 natural sciences ,0104 chemical sciences ,chemistry.chemical_compound ,chemistry ,Remanence ,Rhodamine B ,engineering ,Photocatalysis ,General Materials Science ,Diffuse reflection ,Crystallite ,0210 nano-technology ,Spectroscopy - Abstract
Co1-xMgxFe2O4 (0≤x≤0.5) spinel nanoparticles were synthesized by a simple microwave combustion method. The characterization of the samples were performed using X-ray diffraction (XRD) analysis, scanning electron (SEM) microscopy, energy dispersive X-ray (EDX) analysis, UV–visible and diffuse reflectance (DRS) spectroscopy, photoluminescence (PL) spectroscopy, Fourier transformed infrared (FT-IR) spectroscopy and vibrating sample magnetometry (VSM) analysis. The XRD patterns indicate the formation of cubic inverse spinel structure. The calculated average crystallite size using Debye Scherrer's equation is found to be around 46–38 nm. The morphology of spinel nanoparticles was observed from SEM images and the elemental mapping of magnesium doped cobalt ferrite was obtained by using energy dispersive X-ray technique. Optical studies were carried out for the deeper understanding of the conduction band (CB) and valence band (VB) edges of the synthesized nanoparticles. The intrinsic stretching vibrations of Fe3+-O2- in tetrahedral sites leads to the appearance of IR band at around 573 cm−1. The magnetic properties such as remanence magnetization (Mr), coercivity (Hc) and saturation magnetization (Ms) were calculated from the hysteresis curves. The maximum photocatalytic degradation efficiency for Co0.6Mg0.4Fe2O4 is around (99.5%) when compared to that of CoFe2O4 whose efficiency is around (73.0%). The improvement in photocatalytic degradation efficiency is due to the effective separation and prevention of electron-hole pair recombination. The R2 values for the first order rate kinetics are found to be better than R2 values for the second order rate kinetics and this proves that photocatalytic degradation of RhB dye follows first order kinetics. The probable mechanism for the photocatalytic degradation of RhB dye is proposed.
- Published
- 2017
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