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Search Results: 1 - 10 of 325393 matches for " S. Thirumaran "
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Ultrasonic study of intermolecular association through hydrogen bonding in ternary liquid mixtures
S. Thirumaran,Deepesh George
Journal of Engineering and Applied Sciences , 2009,
Abstract: The ultrasonic velocity, density and viscosity have been measured for the liquid mixtures of cresols namely, m-cresols, o-cresols and p-cresols with N,N-Dimethyl formamide (DMF) in CCl4 at 303, 308 and 313K. The experimental data have been used to calculate the acoustical parameters such as adiabatic compressibility (β), free length (Lf), free volume (Vf), internal pressure (πi), acoustic impedance (Z) and molar volume (Vm). The excess values of some of the above parameters have also been evaluated and fitted to Redlich-Kister Polynomials and the results are interpreted in terms of molecular interactions present in the mixtures.
International Journal of Chemical Research , 2011,
Abstract: The observed experimental parameters such as density (ρ), viscosity (η) and ultrasonic velocity (U) of ternaryliquid mixtures of substituted benzenes such as chlorobenzene, bromobenzene, nitrobenzene, ethylbenzene and tolueneadded in the fixed binary solvent mixtures of (ratio 4:2) acetophenone and 1-heptanol at 303.15, 308.15 and 313.15K weredetermined. The observed experimental data have been utilized to evaluate some of the excess thermo acousticalparameters such as adiabatic compressibility (βE), intermolecular free length (LfE), free volume (VfE), internal pressure (πiE),Gibb’s energy (ΔGE), viscosity (ηE) molar volume (VmE)and Grunberg’s Nissan interaction parameter (d). It is eventuallyobserved that weak molecular association between acetophenone and 1-heptanol is through hydrogen bonding andsubstituted benzenes through weak dipole-dipole interactions. The existence of formation of donor – acceptor complexes inthe present study has been identified and promptly discussed. Further, the impact due to the elevation of temperature onthese liquid systems has also been interpreted.
Structural Elucidation of Some Borate Glass Specimen by Employing Ultrasonic and Spectroscopic Studies
S. Thirumaran,N. Karthikeyan
Journal of Ceramics , 2013, DOI: 10.1155/2013/485317
Abstract: Quantitative analysis has been carried out in order to obtain more information about the structure of two glass systems, namely, (B2O3-MnO2-PbO) (BML glass system) and (B2O3-Na2CO3-P2O5) (BSP glass system). Their structural elucidation has been carried out by studying the ultrasonic velocities (longitudinal velocities and shear velocities ) and density of these glass samples. The present investigation has been interpreted by focusing more on elastic and mechanical properties of glass specimen through ultrasonic study and the elemental analysis study through spectroscopic studies. The scanning electron microscopic (SEM) study was also carried out with a view to throwing more light on their morphological aspects. The results are corroborated in the light of the role of borate (B2O3) glasses in the formation of glassy structural network. 1. Introduction The acoustical properties are particularly suitable for describing glasses as a function of composition because they give some information about both the microstructure and the dynamics of the glasses. The elastic properties are related to microscopic properties through the behavior of the network and the modifier. Attempts have been made to measure and interpret the acoustical properties of borate glasses in terms of structural changes [1–3]. Bahatti and Singh [4] discussed the composition dependence of ultrasonic velocity. The ultrasonic nondestructive testing has been found to be one of the best techniques to study the microstructure, characterization, mechanical properties, and phase changes as well as to evaluate elastic constants. One can also characterize the materials such as semiconducting glasses, superconducting glasses, glass ceramics and bioactive glasses by this nondestructive testing technique. The propagation of ultrasonic wave in solids such as glass provides valuable information regarding the solid state motion in the material. Interest in glasses has rapidly increased in recent years because of diverse applications in electronic, nuclear, solar energy and acoustooptic devices. The acoustic wave propagation in bulk glasses has been of considerable interest to understand the mechanical properties [5]. The velocity of sound is particularly suitable for characterising glasses as function of composition because it gives information about the microstructure and dynamics of glasses [6]. The study of elastic properties of the glasses has inspired many researches [7, 8] and significant information about the same has been obtained. The elastic moduli of glasses are influenced by the many physical
Structure-making and Breaking Behaviour of Some a-amino Acids in Aqueous Sodium Butyrate Medium at 298.15K
S. Thirumaran,K. Job Sabu
Journal of Applied Sciences , 2011,
Abstract: The present study aims for the structure-making and structure-breaking behaviour of some amino acids in aqueous sodium butyrate solution at 298.15 K. The present investigation exploring the possible molecular interactions between the amino acids and organic salts such as sodium butyrate, which is known to have much dissociation of proteins in the solvent mixture. Experimental values of density, viscosity and ultrasonic velocities were carried out on the ternary mixtures of water+sodium butyrate+amino acids namely (L-asparagine, L-glutamine, L-serine and L-threonine) at 298.15 K. The present study was carried out by varying the different mass percentages of binary mixtures (water+sodium butyrate) varying from pure water to 20% (0, 5, 10, 15 and 20%) in increments of 5%. The related and relevant parameters correlated to our present study such as adiabatic compressibility (), molar hydration number (nH), apparent molar compressibility (fK), apparent molar volume (fV), limiting apparent molar compressibility (fk), limiting apparent molar volume (fv) and their associated constants (SK, SV), transfer volume (?fv) from water to aqueous solution viscosity B-Coefficient of Jones-Dole equations were meticulously evaluated. The molecular associations such as ion-ion, ion-solvent, solute-solvent, solute-solute etc are identified and critically discussed in terms of the structure-making and structure-breaking behaviour of amino acids in the solvent mixture.
Bis(1,2,3,4-tetrahydroquinoline-1-thiocarbonyl) disulfide
N. Srinivasan,S. Thirumaran,S. Selvanayagam
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812047320
Abstract: In the title compound, C20H20N2S4, the N-containing six-membered rings of the two tetrahydroquinoline moieties adopt half-chair conformations. Intramolecular C—H...S hydrogen bonding stabilizes the molecular structure. In the crystal, molecules associate via weak C—H...π interactions.
E. Sathiyaraj,S. Thirumaran,S. Selvanayagam
Acta Crystallographica Section E , 2012, DOI: 10.1107/s1600536812036161
Abstract: The molecule of the title compound, [Pb(C16H16NS2)2], is located on a twofold rotation axis, which runs through the PbII atom. The two dithiocarbamate ligands coordinate the metal in a pyramidal configuration through the S atoms. The two phenyl rings of each dithocarbamate ligand are aligned at a dihedral angle of 78.4 (1)°. The molecular conformation is stabilized by intramolecular C—H...S interactions.
P. Valarmathi,S. Thirumaran,S. Selvanayagam
Acta Crystallographica Section E , 2011, DOI: 10.1107/s1600536811050550
Abstract: The NiII atom in the mononuclear title compound, [Ni(C10H10NS2)(NCS)(C18H15P)], exists within a S2PN donor set that defines a distorted square-planar geometry. A significant asymmetry in the Ni—S bond lengths support the less effective trans effect of SCN over PPh3.
Synthesis and Characterization of New Heterocyclic Liquid Crystals
D. Srividhya,S. Manjunathan,S. Thirumaran
Journal of Chemistry , 2009, DOI: 10.1155/2009/697928
Elastic and mechanical properties of glass specimen by ultrasonic method
A. N. Kannappan,S. Thirumaran,R. Palani
Journal of Engineering and Applied Sciences , 2009,
Abstract: Ultrasonic velocity and density measurements in Na2CO3 – ZnO – B2O3 and Na2CO3 – PbO – B2O3 composition glasses have been made at a temperature of 303K. These measured values are used to evaluate elastic modulii such as longitudinal, Young’s, bulk and shear, Poisson’s ratio, acoustic impedance, micro hardness, Debye temperature and thermal expansion coefficient. The results of these parameters have been discussed in terms of the structural and physical properties of the prepared glasses.
Volumetric and Thermodynamic Studies of Molecular Interactions in Ternary Liquid Mixtures at 303, 308 and 313K
AN. Kannappan1,S. Thirumaran,R. Palani
Journal of Physical Science , 2009,
Abstract: Ultrasonic velocity, density and viscosity were measured for mixtures of 1-alkanols, namely, 1-propanol, 1-butanol, 1-pe ntanol and 1-hexanol, with N, N-dimethylformamide (DMF) in cyclohexanone at 303, 308 and 313K. The experimental data were used to calculate the excess free volume (Vf E), excess internal pressure ( π iE),and Gibb’s free energy (ΔG*), which were discussed in the light of molecular interaction existing in the mixtures. It was observed that the addition of DMF to mixtures caused the dissociation of the hydrogen-bonded structure of 1-alkanols. Furthermore, the DMFalkanolinteractions were weaker than the alkanol-ketone interactions in the mixtures.
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