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Search Results: 1 - 10 of 220481 matches for " C. NAGESWARA RAJU "
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Indo-Japanese Lidar Observations of the Tropical Middle Atmosphere During 1998 and 1999
Y BHAVANI KUMAR,C NAGESWARA RAJU,M KRISHNAIAH,
Y. BHAVANI KUMAR
,C. NAGESWARA RAJU,M. KRISHNAIAH

大气科学进展 , 2006,
Abstract: A state-of-the art Rayleigh and Mie backscattering lidar was set up at Gadanki (13.5°N, 79.2°E) in the Tropics in India. Using this system, regular observations of upper tropospheric clouds, aerosols at stratospheric heights and atmospheric temperatures in the range from 30 to 80 km were made. In this paper, the data collected during the period of 1998-99 were selected for systematic investigation and presentation. The Mie scattering lidar system is capable of measuring the degree of depolarization in the laser backscattering. Several tropical cirrus cloud structures have been identified with low to moderate ice content. Occasionally, thin sub-visible cirrus clouds in the vicinity of the tropical tropopause have also been detected. The aerosol measurements in the upper troposphere and lower stratosphere show low aerosol content with a vertical distribution up to 35 km altitude. Rayleigh-scattering lidar observations reveal that at the tropical site, temperature inversion occurs at mesospheric heights. Atmospheric waves have induced perturbations in the temperatures for several times at the upper stratospheric heights. A significant warming in the lower mesosphere associated with a consistent cooling in the upper stratospheric heights is observed particularly in the winter season during the events of sudden stratospheric warming (SSW).
Formation of binary complexes of Co(II), Ni(II) and Cu(II) with L-DOPA in dioxan-water mixtures
Rama Raju Bendi, Venkata Santhee Devi Karri, Nageswara Rao Gollapalli
Bulletin of the Chemical Society of Ethiopia , 2011,
Abstract: Complexation of essential metal ions with (S)-2-amino-3-(3,4-dihydroxyphenyl) propanoic acid (dopa) in (0-60% v/v) dioxan-water mixtures has been studied pH-metrically at a temperature of 303 K and an ionic strength of 0.16 M. The existence of different binary species was established from modeling studies using the computer program MINIQUAD75. The best-fit chemical models were selected based on statistical parameters like crystallographic R factor and sum of the squares of residuals in mass-balance equations. The models for binary complex systems contain the chemical species ML, ML2, MLH, ML2H and ML2H2 for Co(II), Ni(II) and Cu(II) in dioxan-water mixtures. The trend in the variation of stability constants with change in the mole fraction of the medium was explained based on electrostatic and non-electrostatic forces. Distribution of the species with pH at different compositions of dioxan-water mixtures was also presented. KEY WORDS: Binary species, Stability constants, Metal, Dopa, Dioxan, pH-metry Bull. Chem. Soc. Ethiop. 2011, 25(1), 43-52.
Formation of binary complexes of Co(II), Ni(II) and Cu(II) with L-DOPA in dioxan-water mixtures
Rama Raju Bendi,Venkata Santhee Devi Karri,Nageswara Rao Gollapalli
Bulletin of the Chemical Society of Ethiopia , 2011,
Abstract: Complexation of essential metal ions with (S)-2-amino-3-(3,4-dihydroxyphenyl) propanoic acid (dopa) in (0-60% v/v) dioxan-water mixtures has been studied pH-metrically at a temperature of 303 K and an ionic strength of 0.16 M. The existence of different binary species was established from modeling studies using the computer program MINIQUAD75. The best-fit chemical models were selected based on statistical parameters like crystallographic R factor and sum of the squares of residuals in mass-balance equations. The models for binary complex systems contain the chemical species ML, ML2, MLH, ML2H and ML2H2 for Co(II), Ni(II) and Cu(II) in dioxan-water mixtures. The trend in the variation of stability constants with change in the mole fraction of the medium was explained based on electrostatic and non-electrostatic forces. Distribution of the species with pH at different compositions of dioxan-water mixtures was also presented.
Radiative Damping and Functional Differential Equations
C. K. Raju,Suvrat Raju
Physics , 2008, DOI: 10.1142/S021773231103698X
Abstract: We propose a general technique to solve the classical many-body problem with radiative damping. We modify the short-distance structure of Maxwell electrodynamics. This allows us to avoid runaway solutions as if we had a covariant model of extended particles. The resulting equations of motion are functional differential equations (FDEs) rather than ordinary differential equations. Using recently developed numerical techniques for stiff FDEs, we solve these equations for the one-body central force problem with radiative damping with a view to benchmark our new approach. Our results indicate that locally the magnitude of radiation damping may be well approximated by the standard third-order expression but the global properties of our solutions are dramatically different. We comment on the two body problem and applications to quantum field theory and quantum mechanics.
Comparison of Alkaline Treatment of Lead Contaminated Wastewater Using Lime and Sodium Hydroxide  [PDF]
Sudhakar M. Rao, G. C. Raju
Journal of Water Resource and Protection (JWARP) , 2010, DOI: 10.4236/jwarp.2010.23032
Abstract: A lead-acid storage battery manufacturing industry in India produces several thousand liters of lead con-taminated acidic wastewater on a daily basis and uses hydrated lime to render the lead-contaminated acidic wastewater alkaline (pH = 8.0). Alkaline treatment of the acidic wastewater with lime though a cost-effective method, generates copious amount of lead-contaminated gypsum sludge. Other alkali agents such as sodium hydroxide, sodium carbonate and dolomite are also used for alkali treatment of the acid wastewaters. The present paper compares the relative efficiency of hydrated lime and 0.05 M to 1 M NaOH solutions with re-spect to 1) amounts of sludge produced, 2) immobilization of the soluble lead in the acidic wastewater (AWW) and 3) increase in TDS (total dissolved solids) levels upon treatment of AWW with NaOH solutions and lime. The study also performs equilibrium speciation upon alkaline treatment of AWW with lime and NaOH (sodium hydroxide) solutions using the Visual MINTEQ program to understand the chemical reac-tions occurring during treatment process.
Substrate Effect on Plasmon Resonance of a Gold Nanoparticle Embedded Amorphous BaTiO3 Film  [PDF]
S. Ramakanth, K. C. James Raju
Soft Nanoscience Letters (SNL) , 2013, DOI: 10.4236/snl.2013.34A009
Abstract: Two sets of gold nanoparticles (NP) embedded in amorphous BaTiO3 films were prepared by sol-gel method using spin coating. Sample (1) is having BaTiO3 sol with 0.025 gm of Chloroauric acid dissolved in 10 ml of propan-2-ol, while sample (2) is having 0.086 gm of Chloroauric acid in the same amount of propan-2-ol. The films have been deposited on various substrates like borosilicate glass and fused silica. TEM images show that the particles are of 5 and 10 nm in size for the two set of samples, and some are having elongated morphology. Optical absorption properties of these films reveal the substrate and size effect on localised surface plasmon resonance (SPR). It shows a marginal red shift in the plasmon resonance peak from 414 nm to 420 nm in the case of sample (1) and 566 nm to 568 nm for sample (2) as the substrate changed from borosilicate glass to fused silica. It also shows red shift in Plasmon peak as the size increases from 5 to 10 nm and coincides with Mie explanation for the shift with size.
Determination of Phase Transitions of p,n-Alkyloxy Benzoic Acid Mesogens Using Legendre Moments and Image Analysis  [PDF]
S. Sreehari Sastry, C. Nageswara Rao, K. Mallika, S. Lakshminarayan, Ha Sie Tiong
World Journal of Condensed Matter Physics (WJCMP) , 2013, DOI: 10.4236/wjcmp.2013.31010
Abstract:

Phase transition temperatures of p,n-alkyloxy benzoic acids (nOBA, n = 3 to 10 and 12) are investigated basing on the textural image analysis of liquid crystal. The analysis is carried out by the computation of Legendre moments. Textures of the homeotropically aligned compounds are recorded as a function of temperature using POM in arthroscopic mode attached to the hot stage and high resolution camera. A recurrence formula is used to compute the liquid crystal textures based on Legendre polynomial. The discontinuities and fluctuations in the values of Legendre moments as a function of temperature are related to the phase transition temperatures of the sample. This method is successful in conforming or detecting the phase transition temperatures and the present findings are comparable with literature.

 

Speciation Studies of L-Histidine Complexes of Pb(II), Cd(II), and Hg(II) in DMSO-Water Mixtures
K. Bharath Kumar Naik,B. Ananda Kumar,S. Raju,G. Nageswara Rao
International Journal of Inorganic Chemistry , 2012, DOI: 10.1155/2012/265249
Abstract: Equilibrium study on complex formation of L-histidine with Pb(II), Cd(II), and Hg(II) has been investigated pH metrically in DMSO-water mixtures (0–60% v/v) at 303?K and 0.16?mol?L?1 ionic strength. The predominant species detected for Pb(II) and Cd(II) are ML2H4, ML2H3, ML2H2, ML2H, and ML2 and those for Hg(II) are ML2H4, ML2H3, ML2, and ML. The appropriateness of experimental conditions is verified by introducing errors intentionally in the concentrations of ingredients. The models containing different numbers of species were refined by using the computer program MINIQUAD75. The best-fit chemical models were arrived at based on statistical parameters. The trend in variation of stability constants of the complexes with dielectric constant of the medium is attributed to the electrostatic and nonelectrostatic forces. The species distribution and the plausible equilibria for the formation of the species are also presented. 1. Introduction The speciation study of toxic metal ion complexes is useful to understand the role played by the active site cavities in biological molecules and the bonding behavior of protein residues with the metal ion. The species refined and their relative concentrations under the experimental conditions represent the possible forms of aminoacids in biofluids. Due to its numerous uses and high persistence, lead is a major environmental contaminant [1]. Lead is toxic even at low concentrations for living organisms, who can absorb it in various ways [2]. Lead intake by humans can be due to the consumption of crop plants grown on soils with high plant-available metal concentrations [3]. It can, however, migrate through the soil with dissolved organic matter [4] or mobilized by certain plants [5]. Moreover, carried from the air to the soils as fine particles, lead could be released more easily in soil solution [6]. Cadmium causes iron deficiency by binding to cysteine, glutamate, aspartate, and histidine ligands [7]. Cadmium inhibits enzymes that participate in bilirubine conjunction [8]. It increases urine Ca2+ excretion which can cause severe bone pathology [9]. The possible effects of long term low-level exposure to cadmium are of concern because it is readily distributed to tissues of liver and kidney, which are the main target organs in acute and chronic cadmium exposure [10, 11]. Other tissues involved in cadmium toxicity include the testis, heart, bone, eye, and brain [12]. Mercury is one of the most toxic elements and has negative health effects in human populations, highly dependent on fish consumption [13, 14]. Recent
PROTONATION EQUILIBRIA OF L-DOPA AND 1,10 PHENONTHROLINE IN PROPYLENE GLYCOL-WATER MIXTURES
RAMA RAJU,B; SANTHEE DEVI,K V; PADMAJA,N; NAGESWARA RAO,G;
Journal of the Chilean Chemical Society , 2011, DOI: 10.4067/S0717-97072011000400004
Abstract: protonation equilibria of l-dopa and 1,10 phenonthroline have been studied in varying concentrations (0-60% v/v) of propylene glycol-water mixtures maintaining an ionic strength of 0.16 mol dm-3 at 303 k using ph metric method. the protonation constants have been calculated with the computer program miniquad75 and the best fit models are arrived at based on statistical grounds employing crystallographic r factor, χ2 , skewness and kurtosis. dopa has three dissociable protons and one amino group which associate with proton. it exists as lh4+ at low ph and gets deprotonated with the formation of lh3, lh2- and lh2- successively with increase in ph. phen forms lh22+ at low ph and gets deprotonated with the formation of lh+ and l with increase in ph. secondary formation functions confirm the existence of 3 and 2 protonation equilibria for dopa and phen, respectively. the linear increase of log values of protonation constants of dopa with decreasing dielectric constant of pg-water mixtures indicates the dominance of electrostatic forces in the protonation-deprotonation equilibria. phen exhibits non-linear trend indicating the dominance of non-electrostatic forces.
Effect of dielectric constant of medium on chemical speciation of L-histidine complexes of Co(II), Ni(II) and Cu(II)
Raju Sala, Ananda Kumar Bokka, Bharath Kumar Naik Kethavath, Nageswara Rao Gollapalli
Bulletin of the Chemical Society of Ethiopia , 2012,
Abstract: Chemical speciation of binary complexes of Co(II), Ni(II) and Cu(II) ions with L-histidine have been studied pH metrically in the concentration range of 0–60% v/v DMSO-water mixtures maintaining an ionic strength of 0.16 M at 303 K. Alkalimetric titrations were carried out in different relative concentrations of metal and histidine. Stability constants of various models of binary complexes were refined with MINIQUAD75. The best-fit chemical models were selected based on statistical parameters and residual analysis. The species detected are MLH, ML-2, ML2H, ML2H2 and ML2H4 for Co(II); ML-2, ML2H, ML2H2 and ML2H4 for Ni(II); and MLH, ML2, ML2H and ML2H2 for Cu(II). The chemical speciation, metal bioavailability and transportation are explained based on the distribution diagrams. KEY WORDS: L-Histidine, Chemical speciation, Essential metals, Binary complexes, Bioavailability, DMSO Bull. Chem. Soc. Ethiop. 2012, 26(2), 227-238. DOI: http://dx.doi.org/10.4314/bcse.v26i2.6
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