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951 results on '"Mahapatra, M."'

8. Hydroxylation of ZnO/Cu(1 1 1) inverse catalysts under ambient water vapor and the water-gas shift reaction

Author

Orozco, I, Huang, E, Gutiérrez, RA, Liu, Z, Zhang, F, Mahapatra, M, Kang, J, Kersell, H, Nemsak, S, Ramirez, PJ, Senanayake, SD, Liu, P, and Rodriguez, JA

Subjects
warter dissociation, water-gas shift reaction, zno, copper oxide, copper, ambient-pressure x-ray photoeelectron spectroscopy, Applied Physics, Physical Sciences, Engineering
Abstract

The interaction of water vapor with ZnO/CuOx/Cu(1 1 1) surfaces was investigated using synchrotron-based ambient pressure x-ray photoelectron spectroscopy (AP-XPS) and density-functional theory (DFT) calculations. Cu(1 1 1) does not dissociate the water molecule. Cleavage of O-H bonds was seen with AP-XPS after depositing ZnO or preparing CuOx on the copper substrate. The results of DFT calculations show unique behavior for ZnO/CuOx/Cu(1 1 1), not seen on Cu(1 1 1), CuOx/Cu(1 1 1) or ZnO(0 0 0). The ZnO/CuOx/Cu(1 1 1) system binds water quite well and exhibits the lowest energy barrier for O-H bond cleavage. The presence of unsaturated Zn cations in the islands of ZnO led to high chemical reactivity. In order to remove the OH from ZnO/CuOx/Cu(1 1 1) and ZnO/Cu(1 1 1) surfaces, heating to elevated temperatures was necessary. At 500-600 K, a significant coverage of OH groups was still present on the surfaces and did react with CO during the water-gas shift (WGS) process. The final state of the sample depended strongly on the amount of ZnO present on the catalyst surface. For surfaces with a ZnO coverage below 0.3 ML, the adsorption of water did not change the integrity of the ZnO islands. On the other hand, for surfaces with a ZnO coverage above 0.3 ML, a ZnO → ZnxOH transformation was observed. This transformation led to a decrease in the WGS catalytic activity.

Published
2019

9. Measurement of Through-Thickness Residual Stresses Under Restrained Condition in Pressure Vessel Steel Weld

Author

Taraphdar, P. K., Mahapatra, M. M., Pradhan, A. K., Singh, P. K., Sharma, Kamal, Kumar, Suranjit, Chaari, Fakher, Series Editor, Haddar, Mohamed, Series Editor, Kwon, Young W., Series Editor, Gherardini, Francesco, Series Editor, Ivanov, Vitalii, Series Editor, Cavas-Martínez, Francisco, Series Editor, Trojanowska, Justyna, Series Editor, Saran, V. H., editor, and Misra, Rakesh Kumar, editor

Published
2021
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15. Modeling the Resistance Spot Welding of Galvanized Steel Sheets Using Neuro-Fuzzy Method

Author

Boriwal, L., Sarviya, R. M., Mahapatra, M. M., Kacprzyk, Janusz, Series editor, Pal, Nikhil R., Advisory editor, Bello Perez, Rafael, Advisory editor, Corchado, Emilio S., Advisory editor, Hagras, Hani, Advisory editor, Kóczy, László T., Advisory editor, Kreinovich, Vladik, Advisory editor, Lin, Chin-Teng, Advisory editor, Lu, Jie, Advisory editor, Melin, Patricia, Advisory editor, Nedjah, Nadia, Advisory editor, Nguyen, Ngoc Thanh, Advisory editor, Wang, Jun, Advisory editor, Reddy, M. Sreenivasa, editor, Viswanath, K., editor, and K.M., Shiva Prasad, editor

Published
2018
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42. Characterization of AZ91D/Al7075 FGMs fabricated through gravity casting: effect of Zn interface.

Author

Surekha, B., Mahapatra, M M, and Samal, Priyaranjan

Subjects
*FUNCTIONALLY gradient materials, *DIE castings, *GRAVITY, *IMPACT strength, *SHEAR strength
Abstract

The present paper attempts to fabricate the functionally graded materials (FGMs) with two dissimilar metals using Gravity Die Casting (GDC) with and without an interfacing layer. AZ91D and Al7075 alloys are used in this study as base metals. The Zn layer is used as interfacing material to prepare the FGMs. The interfacial microstructures of the said FGMs reveal α-Mg, Al5Mg11Zn4, and MgZn2 compounds. The absence of a Zn interface layer revealed harmful Al-Mg intermetallics such as Al12Mg17, Al3Mg2, and Mg5Al8. The microstructural examination reveals that the presence of the Zn interface protects the diffusion of Al particles with Mg particles. Further studies on the Zn interfacing layer increased the microhardness value, whereas FGMs without interface showed increased shear and impact strength. [ABSTRACT FROM AUTHOR]

Published
2023
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48. Studies on the Adsorption of 2-Chlorophenol onto Rice Straw Activated Carbon from Aqueous Solution and its Regeneration

Author

Mahapatra, M. K. and Kumar, A.

Subjects
adsorption, 2-chlorophenol abatement, rice straw activated carbon, adsorption kinetics, adsorption equilibrium, regeneration
Abstract

For this study a low-cost adsorbent, rice straw activated carbon (RSAC) was prepared via thermochemical routes after being impregnated with ZnCl2. Characterization studies performed on RSAC have revealed that RSAC is a mesoporous adsorbent with significant affinity towards 2-chlorophenol (2-CP). The optimal values for process parameters were investigated via experimental runs. The optimal values of process parameters such as RSAC dose, pH of 2-CP solution, contact time, and temperature were found to be; 1.25 g L–1, 8, 125 min, and 303 K, respectively. The Langmuir isotherm and pseudo-first-order kinetics models were found to be in good agreement with the experimental data for this adsorption system. The adsorption thermodynamics studies have revealed that the adsorption of 2-CP onto RSAC is exothermic and spontaneous. Regeneration studies of RSAC using hydrogen peroxide have revealed that RSAC was effectively regenerated for four consecutive cycles. This research has proved the potential of RSAC for abating 2-CP from aqueous solutions. This work is licensed under a Creative Commons Attribution 4.0 International License.

Published
2022

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