Mahendra Educational Institutions

Nāmakkal, India

Mahendra Educational Institutions

Nāmakkal, India
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Gnanendra T.S.,Mahendra Educational Institutions | Anbarasan P.M.,Periyar University | Aroulmoji V.,Mahendra Educational Institutions
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2015

In this work, we reported a combined experimental and theoretical study on molecular structure, vibrational spectra and Homo-Lumo analysis of Purpurin and TiO2/Purpurin. The geometries, electronic structures, molecular orbital analysis of natural dye sensitizer Purpurin were studied based on density functional theory (DFT) using the hybrid functional B3LYP. Fourier transform infrared (FT-IR) and FT-Raman spectra have been recorded and extensive spectroscopic investigations have been carried out on Purpurin. The optimized geometries, wave number and intensity of the vibrational bands of Purpurin have been calculated using density functional level of theory (DFT/B3LYP) employing 6-311G (d,p) basis set. Based on the comparison between calculated and experimental results, assignments of the fundamental vibrational modes are examined. Features of the electronic absorption spectrum in the visible and near-UV regions were assigned based on TD-DFT calculations. The calculated results suggest that the three excited states with the lowest excited energies in 1,2,4, trihydroxy 9-10 anthraquinone was due to photo-induced electron transfer processes. Frontier molecular orbitals (FMO), LUMO, HOMO, and energy gap, of these dyes have been analyzed to show their effect on the process of electron injection and dye regeneration. Interaction between HOMO and LUMO of Purpurin are investigated to understand the recombination process and charge transfer process involving these dyes. We also performed analysis of I-V characteristics to investigate the role of charge transfer and the stability of the dye molecule. © 2015 Elsevier B.V.


Mohr T.,Mahendra Educational Institutions | Mohr T.,Ulm University of Applied Sciences | Aroulmoji V.,Mahendra Educational Institutions | Ravindran R.S.,Mahendra Educational Institutions | And 3 more authors.
Spectrochimica Acta - Part A: Molecular and Biomolecular Spectroscopy | Year: 2015

The geometries, electronic structures, polarizabilities and hyperpolarizabilities of 2-hydroxynaphthalene-1,4-dione (henna1), 3-(5-((1E)-2-(1,4-dihydro-1,4-dioxonaphthalen-3-yloxy) vinyl) thiophen-2-yl)-2-isocyanoacrylic acid (henna2) and anthocyanin dye sensitizers were studied based on density functional theory (DFT) using the hybrid functional B3LYP. The Ultraviolet-Visible (UV-Vis) spectrum was investigated by using a hybrid method which combines the properties and dynamics of many-body in the presence of time-dependent (TD) potentials, i.e. TDSCF-DFT (B3LYP). Features of the electronic absorption spectrum in the visible and near-UV regions were plotted and assigned based on TD-DFT calculations. Due to the absorption, bands of the metal-organic compound are n → π* present. The calculated results suggest that the three lowest energy excited states of the investigated dye sensitizers are due to photoinduced electron transfer processes. The interfacial electron transfer between semiconductor TiO2 electrode and dye sensitizer is owing to an electron injection process from excited dye to the semiconductor's conduction band. The role of linking the henna1 dye with a carboxylic acid via a thiophene bridge was analyzed. The results are that using a stronger π-conjugate bridge as well as a strong donator and acceptor group enhances the efficiency. © 2014 Elsevier B.V. All rights reserved.


Hariharan V.,Mahendra Arts and Science College | Aroulmoji V.,Mahendra Educational Institutions | Prabakaran K.,Mahendra Arts and Science College | Gnanavel B.,CN College | And 3 more authors.
Journal of Alloys and Compounds | Year: 2016

Nanocrystalline WO3·H2O nanopowders, doped with cobalt (2 and 5 wt%) have been synthesized using CoCl2·6H2O and Na2WO4·2H2O in a facile microwave irradiation process, followed by the annealing process. The samples were characterized with powder X-ray diffraction, field emission scanning electron microscopy, UV-VIS diffusion reflectance spectroscopy, photoluminescence spectroscopy and cyclic voltammetry (CV). X-ray diffraction patterns showed both undoped and Co doped WO3·H2O crystallized with orthorhombic phase. Annealing h-WO3at 600 °C 6 h in air resulted in the different products, W17O47(monoclinic) for undoped, WO3orthorhombic for 2 wt% Co doped and WO3(monoclinic) for 5 wt% Co doped. FE-SEM micrographs suggested that the dopants are able to influence the growth rate and morphology of the prepared nanopowders. UV-VIS-DRS spectra revealed that the dopant (Co ion) is incorporated in the intermediate energy level. Blue emissions (450–550 nm) were verified using PL at room temperature for the annealed samples (W17O47and WO3) with excitation wavelength 390 nm. The difference in peak intensity observed through PL spectra attributed to the possible distortions in WO4 2−tetrahedron group during microwave irradiation process. Electrochemical studies showed the possible enhanced catalytic behaviour of cobalt doped (5 wt%) as prepared samples than that of others. The temperature dependent magnetic susceptibility (300 K–2 K) and isothermal magnetization measurements showed the enhancement in magnetic behaviour of the samples for diamagnetic to antiferromagnetic nature which is clearly shows the incorporation of Cobalt ion at tungsten lattice site and in determining the resultant magnetic behaviour of the samples. © 2016


Aroulmoji V.,Mahendra Educational Institutions | Mohr T.,Mahendra Educational Institutions | Mohr T.,Ulm University of Applied Sciences | Anbarasan P.M.,Periyar University
Acta Physica Polonica A | Year: 2014

The geometries, electronic structures, polarizabilities, and hyperpolarizabilities of natural dye sensitizer alizarin from madder fruit was studied based on density functional theory using the hybrid functional B3LYP. Features of the electronic absorption spectra in the visible and near-UV regions were assigned based on time- -dependent density function theory calculations. The calculated results suggest three excited states with the lowest excited energies in 1,2-dihydroxy-9,10-anthraquinone and it was due to photoinduced electron transfer processes. The interfacial electron transfer between semiconductor TiO2electrode and dye sensitizer 1,2-dihydroxy-9,10- -anthraquinone is due to an electron injection process from excited dye to the semiconductor conduction band. The importance of hydroxyl group in geometries, electronic structures and spectral properties were reported.


PubMed | Mahendra Educational Institutions, Ulm University of Applied Sciences and Periyar University
Type: | Journal: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy | Year: 2014

The geometries, electronic structures, polarizabilities and hyperpolarizabilities of 2-hydroxynaphthalene-1,4-dione (henna1), 3-(5-((1E)-2-(1,4-dihydro-1,4-dioxonaphthalen-3-yloxy) vinyl) thiophen-2-yl)-2-isocyanoacrylic acid (henna2) and anthocyanin dye sensitizers were studied based on density functional theory (DFT) using the hybrid functional B3LYP. The Ultraviolet-Visible (UV-Vis) spectrum was investigated by using a hybrid method which combines the properties and dynamics of many-body in the presence of time-dependent (TD) potentials, i.e. TDSCF-DFT (B3LYP). Features of the electronic absorption spectrum in the visible and near-UV regions were plotted and assigned based on TD-DFT calculations. Due to the absorption, bands of the metal-organic compound are n(*) present. The calculated results suggest that the three lowest energy excited states of the investigated dye sensitizers are due to photoinduced electron transfer processes. The interfacial electron transfer between semiconductor TiO2 electrode and dye sensitizer is owing to an electron injection process from excited dye to the semiconductors conduction band. The role of linking the henna1 dye with a carboxylic acid via a thiophene bridge was analyzed. The results are that using a stronger -conjugate bridge as well as a strong donator and acceptor group enhances the efficiency.


PubMed | Mahendra Educational Institutions and Periyar University
Type: | Journal: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy | Year: 2015

In this work, we reported a combined experimental and theoretical study on molecular structure, vibrational spectra and Homo-Lumo analysis of Purpurin and TiO2/Purpurin. The geometries, electronic structures, molecular orbital analysis of natural dye sensitizer Purpurin were studied based on density functional theory (DFT) using the hybrid functional B3LYP. Fourier transform infrared (FT-IR) and FT-Raman spectra have been recorded and extensive spectroscopic investigations have been carried out on Purpurin. The optimized geometries, wave number and intensity of the vibrational bands of Purpurin have been calculated using density functional level of theory (DFT/B3LYP) employing 6-311G (d,p) basis set. Based on the comparison between calculated and experimental results, assignments of the fundamental vibrational modes are examined. Features of the electronic absorption spectrum in the visible and near-UV regions were assigned based on TD-DFT calculations. The calculated results suggest that the three excited states with the lowest excited energies in 1,2,4, trihydroxy 9-10 anthraquinone was due to photo-induced electron transfer processes. Frontier molecular orbitals (FMO), LUMO, HOMO, and energy gap, of these dyes have been analyzed to show their effect on the process of electron injection and dye regeneration. Interaction between HOMO and LUMO of Purpurin are investigated to understand the recombination process and charge transfer process involving these dyes. We also performed analysis of I-V characteristics to investigate the role of charge transfer and the stability of the dye molecule.


Banu P.K.N.,B.S. Abdur Rahman University | Andrews S.,Mahendra Educational Institutions
Proceedings of the 2013 International Conference on Current Trends in Information Technology, CTIT 2013 | Year: 2013

Feature selection is one of the major challenges in the analysis of gene expression data, as the number of genes significantly exceeds the number of samples. Principal Component Analysis (PCA), one of the most popular dimensionality reduction techniques, reveals the underlying factors or combinations of original variables without any information loss. This paper studies the application of PCA based on Eigen vectors of covariance and Singular Value Decomposition (SVD) for gene expression dataset as well and explores the problem of feature subset selection, by selecting highly dominating genes to predict cancer at an early stage. The proposed Informative Gene Selection method aims to identify a subset of genes with higher accuracy to represent original genes. Computational time and clustering accuracy is also recorded separately. The proposed method results with more interpretable features that help to identify the target disease quickly. The prominent results show the effectiveness of the proposed algorithm. © 2013 IEEE.


Niraimathi V.,Salem College | Aroulmoji V.,Mahendra Educational Institutions | Anbarasan P.M.,Periyar University | Rajarajan G.,Mahendra Educational Institutions
Journal of Optoelectronics and Advanced Materials | Year: 2015

The influence of dopant Mg2+ on the growth process, crystalline properties of potassium acid phthalate (KAP) has been investigated. Optically transparent single crystals have been grown from aqueous solution by slow evaporation technique. Powder X-ray diffraction (XRD) and inductively coupled plasma-optical emission spectrometry (ICP-OES) studies confirmed the Mg2+ ion doping into KAP crystals. The modes of vibration in the crystal lattice have been determined by Fourier Transform Infrared (FTIR) analysis. Optical transmission studies were carried out by allowing the UV-NIR ray of wavelength between 190 and 1000 nm, which is to pass through the (010) face of the grown KAP crystals and the results confirm that both the pure and doped KAP single crystal shows good transparency in the entire visible region, which is suitable for optical device applications. Thermogravimetric (TGA) studies reveal that the purity of the sample and no decomposition is observed below the melting point. Microhardness studies reveal that the Mg2+ doped crystals have higher hardness values than that of pristine KAP. Dielectric constant value of Mg2+ doped KAP at 100 Hz was found to be extensively higher than that of pristine KAP. The grown crystals were also subjected to second harmonic generation (SHG) efficiency tests.


Niraimathi V.,Salem College | Aroulmoji V.,Mahendra Educational Institutions | Rajarajan G.,Mahendra Educational Institutions
Optik | Year: 2015

This article has been retracted: please see Elsevier Policy on Article Withdrawal (http://www.elsevier.com/locate/withdrawalpolicy). This article has been retracted at the request of the Author with the Editor's approval. The article is a duplicate of a paper that has already been published in JOURNAL OF OPTOELECTRONICS AND ADVANCED MATERIALS Vol. 17, No. 1-2, January-February 2015. One of the conditions of submission of a paper for publication is that authors declare explicitly that the paper is not under consideration for publication elsewhere. As such this article represents a severe abuse of the scientific publishing system. The scientific community takes a very strong view on this matter and apologies are offered to readers of the journal that this was not detected during the submission process.


Dharmalingam T.,Salem College | Udhaya V.,Annamalai University | Umaarasu T.,Vivekananda Dental College for Women | Elangovan V.,Salem College | And 2 more authors.
Current HIV Research | Year: 2015

The emergence of drug resistance among HIV-positive patients undergoing Anti- Retroviral Therapy (ART) with poor adherence to the HAART is a major concern in India. As the HIV accumulates the key mutations, the drug resistance occurs, that pose challenges to the ART regimens currently being used. Thus, the present study was carried out among the ART- naive patients attending ART Centre at Salem district, Tamil Nadu, India. The mutations that concern the drug resistance were discriminated by determining the viral load before and after 6 months. The drug resistance was analyzed by HIV genotyping from the patients possessing a viral load of >1000 copies/mL after 6 months of ART. The mutations pertaining to drug resistance were analyzed by the online Stanford HIV Database. The 3D structures of the RT were modeled and the drugs used in the first-line regimens were docked to explore the effect of mutations on the binding pattern of the drugs. Among the 250 patients, the viral load data were obtained for 213 patients. The study found 23 patients with both virological and immunological failures and HIV drug mutations were also revealed by genotyping. The mutations of I135R/T/V/X, L178 I/M, M184V/I, D67N, K70R, and K103N were the most common among these 23 patients. The present study revealed that the NACO recommended first-line ART regimen is efficient in most of the patients attending ART center. The emergence of drug resistance of HIV variant is common even under the best circumstance of ART. This study reveals that there is a necessity for the implementation of improved and economically systematic attempt that allows the clinicians to make a rational choice of therapy regimen to overcome the first- line therapy failures among the ART- naive. © 2015 Bentham Science Publishers.

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