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Arjunan V.,Kanchi Mamunivar Center for Post Graduate Studies | Raj A.,Kanchi Mamunivar Center for Post Graduate Studies | Sakiladevi S.,Ar Engineering College | Carthigayan K.,Dr Br Ambedkar Polytechnic College | Mohan S.,Hawassa University
Journal of Molecular Structure | Year: 2012

The structural characteristics and substituent effects of o-Chloronitrobenzene, m-Chloronitrobenzene and p-Chloronitrobenzene have been analysed by experimental FTIR, FT-Raman and FT-NMR spectroscopic studies. A detailed quantum chemical calculations have been performed using DFT/B3LYP method with 6-311++G, 6-31G and cc-pVTZ basis sets. Complete vibrational analyses of the compounds were performed. The temperature dependence of thermodynamic properties has been analysed. The atomic charges and charge delocalisation of the molecule have been performed by natural bond orbital (NBO) analysis. Molecular electrostatic surface potential (MESP), total electron density distribution and frontier molecular orbitals (FMOs) are constructed at B3LYP/6-311++G level to understand the electronic properties. The charge density distribution and site of chemical reactivity of the molecules has been obtained by mapping electron density isosurface with electrostatic potential surfaces (ESPs). The electronic properties, HOMO and LUMO energies were measured by time-dependent TD-DFT approach. 1H and 13C NMR spectra were recorded and 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were calculated. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecules in chloroform solvent were calculated by using the Gauge-Independent Atomic Orbital (GIAO) method and are found to be in good agreement with experimental values. © 2011 Elsevier B.V. All rights reserved. Source


Arjunan V.,Kanchi Mamunivar Center for Post Graduate Studies | Kalaivani M.,Kanchi Mamunivar Center for Post Graduate Studies | Sakiladevi S.,Ar Engineering College | Carthigayan C.,Dr Br Ambedkar Polytechnic College | Mohan S.,Hawasa University Main Campus
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

N-(2,4-Dimethylphenyl)-2,2-dichloroacetamide (24DMPA) and N-(3,5-dimethylphenyl)-2,2-dichloroacetamide (35DMPA) of the configuration X yC 6H 5-yNHCOCHCl 2 (where, X = CH 3 and y = 2) were synthesised and an extensive spectroscopic investigations have been carried out. The ab initio and DFT studies were carried out with 6-31G** and cc-pVDZ basis sets to determine the structural, thermodynamical and vibrational characteristics of the compounds and also to understand the steric influence of methyl groups on the characteristic frequencies of amide (CONH) group. The most stable conformer has been determined by PES scan. Normal co-ordinate analysis has been carried out in an effort to provide mixing of the fundamental modes with the help of potential energy distribution (PED). The energies of the frontier molecular orbitals have been determined. Complete NBO analysis was also carried out to find out the intramolecular electronic interactions and their stabilisation energy. All the computed values are well agreed with the experimental data. © 2011 Elsevier B.V. All rights reserved. Source


Arjunan V.,Kanchi Mamunivar Center for Post Graduate Studies | Sakiladevi S.,Ar Engineering College | Mythili C.V.,Rani Anna Government College for Women | Mohan S.,Hawasa University Main Campus
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2012

The FT-IR (4000-400 cm -1) and FT-Raman (4000-100 cm -1) spectral measurements and complete assignments of the observed spectra of 2-amino-4-methylbenzothiazole (2A4MBT) have been proposed. Ab initio and DFT calculations have been performed and the structural parameters of the compound were determined from the optimised geometry with 6-31G(d,p), 6-311++G(d,p) and cc-pVDZ basis sets and giving energies, harmonic vibrational frequencies, depolarisation ratios, IR intensities and Raman activities. 1H and 13C NMR spectra were recorded and 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were calculated using the gauge independent atomic orbital (GIAO) method. UV-visible spectrum of the compound was also recorded and the electronic properties, such as HOMO, LUMO and band gap energies were measured by time-dependent DFT (TD-DFT) approach. The geometric parameters, energies, harmonic vibrational frequencies, IR intensities, Raman activities chemical shifts and absorption wavelengths were compared with the available experimental data of the molecule. The influences of methyl and amino groups on the skeletal modes and on the proton chemical shifts have been investigated. © 2011 Elsevier B.V. All rights reserved. Source


Arjunan V.,Kanchi Mamunivar Center for Post Graduate Studies | Sakiladevi S.,Ar Engineering College | Kalaivani M.,Kanchi Mamunivar Center for Post Graduate Studies | Mohan S.,Hawassa University
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2011

Experimental FTIR, FT-Raman and FT-NMR spectroscopic studies of o-fluoronitrobenzene and p-fluoronitrobenzene have been carried out. A detailed quantum chemical calculations have been performed using DFT/B3LYP method with 6-311++G** and 6-31G** basis sets. Complete vibrational analyses of the compounds were performed. The temperature dependence of thermodynamic properties has been analysed. The atomic charges, electronic exchange interaction and charge delocalisation of the molecule have been performed by natural bond orbital (NBO) analysis. Molecular electrostatic surface potential (MESP), total electron density distribution and frontier molecular orbitals (FMOs) are constructed at B3LYP/6-311++G** level to understand the electronic properties. The charge density distribution and site of chemical reactivity of the molecules have been obtained by mapping electron density isosurface with electrostatic potential surfaces (ESP). The electronic properties, HOMO and LUMO energies were measured by time-dependent TD-DFT approach. 1H and 13C NMR spectra were recorded and 1H and 13C nuclear magnetic resonance chemical shifts of the molecule were calculated. The 1H and 13C nuclear magnetic resonance (NMR) chemical shifts of the molecules in chloroform solvent and in gas phase were calculated by using the Gauge-Independent Atomic Orbital (GIAO) method and are found to be in good agreement with experimental values. The theoretical parameters obtained at B3LYP levels have been compared with the experimental values. © 2011 Elsevier B.V. All rights reserved. Source


Purushothaman R.,Pondicherry Engineering College | Mani S.,Ar Engineering College
ACI Materials Journal | Year: 2014

Recycled aggregate obtained from crushed concrete rubble can be reused in building industry, instead of being stored. An attempt has been made to study the possibility of reusing the recycled concrete aggregate from demolished structures in place of fresh natural aggregate. The basic properties of aggregates, such as water absorption, specific gravity, and bulk density, and mechanical properties, such as crushing value, impact value, and abrasion resistance, were considered. Twelve series of mixtures comprising reference concrete with natural aggregate and 100% recycled concrete aggregate with natural fine aggregate replaced with quarry dust ranging from 10 to 100% were prepared for this study. All these mixtures were designed for M30 grade (f c' = 24 MPa [3480 psi]) of concrete. Workability of fresh concrete and strength parameters of hardened concrete, such as compressive strength and tensile strength, were studied. In this work, a comparison was made between the results of a laboratory investigation on various physical properties of concrete made with 100% recycled aggregate concrete and 100% natural aggregate concrete and found that the results are encouraging to use this 100% recycled aggregate concrete with quarry dust. Copyright © 2014, American Concrete. Source

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