S. Kumar

Asthagiri Herbal Research Foundation, Chennai, Tamil Nādu, India

Are you S. Kumar?

Claim your profile

Publications (20)15.84 Total impact

  • IOSR Journal of Applied Physics 01/2014; 6(2):59-63. DOI:10.9790/4861-06225963 · 1.35 Impact Factor
  • IOSR Journal of Applied Physics 01/2014; 6(2):64-68. DOI:10.9790/4861-06226468 · 1.35 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: Densities (ρ), viscosities (η) and refractive indices (nD) were measured for the binary mixtures of o- and m-chloroaniline with 2-alkoxyethanols like 2-methoxyethanol, 2-ethoxyethanol and 2-butoxyethanol at 303.15 K. From the experimental data, the values of excess molar volume (VE), deviation of viscosity (ηE), deviation of refractive index (ΔnD), excess molar refraction (RmE) and excess Gibbs free energy (ΔG⁎ E) for the six binary mixtures were calculated and the values are fitted with Redlich–Kister polynomial equation. The values of all calculated parameters of the binary mixtures and their deviations indicate a strong specific type of interaction between the amino group (single bondNH2) of chloroanilines with hydroxyl group (single bondOH) of 2-alkoxyethanols.
    Journal of Molecular Liquids 12/2013; 188(1):203-209. DOI:10.1016/j.molliq.2013.09.035 · 2.08 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: Alcoholysis of sodium borohydride offers advantages due to reduction in number of steps for recycling of sodium borohydride, elimination of freezing problems that are associated with the use of water, fast generation of hydrogen, etc. Methanol was used to liberate hydrogen from sodium borohydride. The influence of the amount of solvent, substrate concentration, temperature and catalyst on the kinetics of alcoholysis reaction in non‐stabilized sodium borohydride has been examined in the present study. The reaction was found to be first order with respect to substrate concentration and zero order with respect to solvent concentration. Effect of soluble metal salts, metal powder and metal boride as catalysts on hydrogen generation rate has also been investigated. It was found that NiCl2, Ni2B and RuCl3 were effective catalysts and hydrogen generation proceeds with high efficiency in the presence of these catalysts. Copyright © 2013 John Wiley & Sons, Ltd.
    International Journal of Energy Research 11/2013; 37(14). DOI:10.1002/er.3006 · 2.74 Impact Factor
  • [Show abstract] [Hide abstract]
    ABSTRACT: The dielectric properties of aniline, o–chloroaniline and o–anisidine with carbon tetrachloride were calculated at 303.15 K. The Kirkwood correlation factor (g) described something about the orientational ordering of molecules in a liquid through the angular correlations of neighboring dipoles and hence it will give useful information about the local structure of the liquid. The calculated values of excess dielectric constant (εE), excess molar polarization (PE) and excess Helmholtz free energy (ΔFE) suggests that the structural behaviour and dipolar rotation of the binary liquid mixtures. The Bruggeman factor (fB) values are deviate from unity, which describe the interaction behaviour of the above said anilines in carbon tetrachloride. From all the studied systems indicates the solute–solvent type of interactions taking place
  • S. Kumar, P. Jeevanandham
    [Show abstract] [Hide abstract]
    ABSTRACT: Densities, viscosities and refractive indices have been measured for the binary mixtures of aromatic amines such as aniline and o-anisidine with 2-alkoxyethanols like 2-methoxyethanol, 2-ethoxyethanol and 2-butoxyethanol at 303.15 K. The excess properties are excess molar volume (VE), deviation of viscosity (ηE), deviation of refractive index (ΔnD), excess molar refraction (RmE) and excess Gibbs free energy (ΔG* E) for the six binary mixtures that were calculated and the values are fitted with Redlich–Kister polynomial equation. The measured refractive index values are analyzed by different theoretical mixing rules and the standard deviations are predicted. From the values of excess properties of the binary mixtures and its deviations indicate that a strong specific type of interaction is formed between the amino group (–NH2) of aniline and o-anisidine with hydroxyl group (–OH) of 2-alkoxyethanols. The strength of interaction is in the following order: aniline > o-anisidine in 2-alkoxyethanols (2-BE > 2-EE > 2-ME). Further the hydrogen bonding interaction of anilines with 2-alkoxyethanols is confirmed by FT-IR spectra.
    Journal of Molecular Liquids 10/2012; 174:34–41. DOI:10.1016/j.molliq.2012.07.025 · 2.08 Impact Factor
  • S.Kumar, P.Jeevanandham
    [Show abstract] [Hide abstract]
    ABSTRACT: Densities, viscosities and refractive indices have been measured for the binary mixtures of aromatic amines such as aniline and o-anisidine with 2-alkoxyethanols like 2-methoxyethanol, 2-ethoxyethanol and 2-butoxyethanol at 303.15 K. The excess properties are excess molar volume (VE), deviation of viscosity (ηE), deviation of refractive index (nDE), excess molar refraction (RmE) and excess Gibbs free energy (ΔG* E) for the six binary mixtures that were calculated and the values are fitted with Redlich–Kister polynomial equation. The measured refractive index values are analyzed by different theoretical mixing rules and the standard deviations are predicted. From the values of excess properties of the binary mixtures and its deviations indicate that a strong specific type of interaction is formed between the amino group (–NH2) of aniline and o-anisidine with hydroxyl group (–OH) of 2-alkoxyethanols. The strength of interaction is in the following order: aniline > o-anisidine in 2-alkoxyethanols (2-BE > 2-EE > 2-ME). Further the hydrogen bonding interaction of anilines with 2-alkoxyethanols is confirmed by FT-IR spectra.
    Journal of Molecular Liquids 07/2012; · 2.08 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The incidence of acute kidney injury (AKI) after cardiac surgery remains high. The nonspecific adenosine receptor antagonist aminophylline has been shown to confer benefit in experimental and clinical acute renal failure (ARF) due to ischemia, contrast media, and various nephrotoxic agents. We conducted a prospective open label trial to assess the effectiveness of aminophylline for prevention of renal impairment after cardiac surgery. One hundred and thirty-eight patients undergoing cardiac surgery were risk stratified as per Cleveland score to assess for prediction of AKI. Sixty-three patients received a bolus aminophylline of 5 mg/kg and a subsequent continuous infusion of 0.25 mg/kg/h for up to 72 h, while 75 patients received usual postoperative care. Serum creatinine concentrations were measured preoperatively and daily until day 5 after surgery and the glomerular filtration rate estimated using Cockcroft and Gault formula. Hourly urine output was recorded and patients assigned to respective RIFLE stage of AKI. Cleveland score ≥6 was associated with higher incidence of AKI: I and F (P<0.005). Number needed to treat, an insight into the clinical relevance of a specific treatment, is 8. These results suggest that the perioperative use of aminophylline infusion is associated with lower incidence of deterioration in renal function following cardiac surgery in high-risk patients.
    Indian Journal of Nephrology 05/2012; 22(3):179-83. DOI:10.4103/0971-4065.98752
  • [Show abstract] [Hide abstract]
    ABSTRACT: Aloin (10-glucopyranosyl-1,8-dihydroxy-3-hydroxymethyl-9(10H)-anthracenone), a bioactive compound in Aloe vera, although known to have an anticancer effect, has not been used in current drug research. Optimization of the lead structure could enhance the utility of this compound. Hence, aloin was modified using natural amino acids to produce Schiff's base, a potential pharmacophore, and its corresponding aglycones. The synthetic derivatives exhibited significant enhancement in their efficacy toward antioxidant (DPPH radical scavenging) and cytotoxic activities than those of the parent compound, aloin showing promise for application in cancer treatment.
    Journal of Asian natural products research 05/2010; 12(5):360-70. DOI:10.1080/10286021003775327 · 0.97 Impact Factor
  • Indian Journal of Thoracic and Cardiovascular Surgery 03/2006; 22(1):63-63. DOI:10.1007/s12055-006-0601-1
  • Indian Journal of Thoracic and Cardiovascular Surgery 03/2006; 22(1):81-81. DOI:10.1007/s12055-006-0669-7
  • [Show abstract] [Hide abstract]
    ABSTRACT: Dielectric relaxation study of amine–alcohol mixtures have been carried out for different concentrations at 303 K. Time Domain Reflectometry (TDR) in reflection mode has been used to measure the reflection coefficient in the frequency range of 10 MHz to 20 GHz. The bilinear calibration method has been used to obtain dielectric quantities viz., static dielectric constant (ε0) and relaxation time (τ). Using these fundamental dielectric quantities the parameters like the Bruggeman factor, Kirkwood correlation factor and excess relaxation time were evaluated. The Bruggeman factor (FBM) shows a positive deviation for pyridine [PYR] with the alcohol system and it shows a negative deviation for triethylamine [TEA] with the alcohol system. The effective Kirkwood correlation factor (geff) is almost unity for amines and > 1 for alcohols and their mixtures, showing parallel orientation of dipoles. The relaxation time is increasing with increasing chain length of the alcohols and it is decreasing with increasing amine concentration. The enthalpy of activation (ΔFτ) for the dielectric relaxation is always greater than the theoretically predicted values for all the mixtures studied.
    Journal of Molecular Liquids 11/2005; 122(1):11-14. DOI:10.1016/j.molliq.2004.11.004 · 2.08 Impact Factor
  • Indian Journal of Thoracic and Cardiovascular Surgery 01/2004; 20(1):11-11. DOI:10.1007/s12055-004-0316-0
  • Source
    S. Kumar, S. Krishnan, D. Manocha
    [Show abstract] [Hide abstract]
    ABSTRACT: A new paradigm for designing complex engineering systems has emerged from computer graphics and CAD/CAM technology. Virtual design environments allow users to design and visualize all stages of the product. They not only free designers from the two dimensions of pencil and paper but also eliminate costly construction of physical mock-ups. We are developing the necessary technology for interactive walkthroughs of large mechanical and architectural models. This development includes model construction, display and interfacing with high-performance graphics systems and immersive technologies. Our ultimate goal is to create an environment where users will explore the complete model of a large design, such as a submarine, and verify that all constraints are satisfied in the same way they would a real one-by walking around in it. In applying our approach to a submarine storage and handling system model, we improved the overall frame rate by three to four times compared with rendering the polygonal B-rep. The online triangulation allows us to spend our rendering resources in the parts of the model significant for the current image. The overall system is currently being applied to large CAD models like submarines and fighting vehicles
    IEEE Computer Graphics and Applications 04/1996; DOI:10.1109/38.486674 · 1.12 Impact Factor
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: We present efficient parallel algorithms for interactive display of higher order surfaces on current graphics systems. At each frame, these algorithms approximate the surface by polygons and rasterize them over the graphics pipeline. The time for polygon generation for each surface primitive varies between successive frames and we address issues in distributing the load across processors for different environments. This includes algorithms to statically distribute the primitives to reduce dynamic load imbalance as well a distributed wait-free algorithm for machines on which re-distribution is efficient, e.g. shared memory machine. These algorithms have been implemented on different graphics systems and applied to interactive display of trimmed spline models. In practice, we are able to obtain almost linear speed-ups (as a function of number of processors). Moreover, the distributed wait-free algorithm is faster by 25-30% as compared to static and dynamic schemes.
    Supercomputing, 1996. Proceedings of the 1996 ACM/IEEE Conference on; 02/1996
  • S. Kumar, D. Manocha
  • Source
    [Show abstract] [Hide abstract]
    ABSTRACT: The dielectric relaxation and dipole moment of different concentration binary mixtures of Ethylene glycol, Propylene glycol and Butylene glycol with dilute solutions of 1,4-Dioxane at 33°C. The dielectric relaxation of binary mixtures of polar liquids in non polar solvents at microwave frequencies has been attempted such studies provide meaningful information regarding intermolecular and intramolecular association between the solutes and solvent molecules. The static dielectric constants (e 0) of glycols like ethylene glycol, propylene glycol and butylene glycol in dilute solutions of 1,4-Dioxane were determined at 303K. The measuring frequency of the dipole meter was 2MHz. X-band and J-band microwave benches operating at 9.52GHz and 7.72GHz were used for determination dielectric permittivity (e¢) and dielectric loss factor (e²). The values of molecular relaxation time (t 0) and dipole moment (m) for the different composition of binary mixtures are determined. The comparative values of relaxation time (t 0) of the two bands (X-Band) and (J-Band) for various binary mixture molecular conformation of these system.
  • Source

Publication Stats

41 Citations
15.84 Total Impact Points

Top co-authors View all

Institutions

  • 2010–2013
    • Asthagiri Herbal Research Foundation
      Chennai, Tamil Nādu, India
  • 2005–2013
    • Annamalai University
      • Department of Physics
      Anamalainagar, Tamil Nādu, India
  • 2004–2012
    • Meenakshi Mission Hospital & Research Centre (S.R. Trust ),
      Mathurai, Tamil Nadu, India
  • 1996
    • University of North Carolina at Chapel Hill
      North Carolina, United States