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Ramana C.V.,Central University of Costa Rica | Parag B.,Central University of Costa Rica | Girija K.R.,Central University of Costa Rica | Raghu Ram B.,Central University of Costa Rica | And 2 more authors.
International Journal of Systematic and Evolutionary Microbiology | Year: 2013

Two strains (JC85T and JC108) of Gram-stain-negative, motile bacteria were isolated from endolithic beach sand samples on an oligotrophic medium. Based on the 16S rRNA gene sequence analysis, both strains were identified as belonging to the genus Rhizobium. Strain JC108 had 16S rRNA gene sequence similarity of 100% with Rhizobium pusense NRCPB10T and formed a cluster with this strain. Strain JC85T had 96.9% 16S rRNA gene sequence similarity and was 18% related (based on DNA-DNA hybridization) to Rhizobium borbori DN316T. With other strains of the genus Rhizobium, the 16S rRNA gene sequence similarity was less than 96.3%. Strain JC85T could tolerate up to 3% salinity, fix N2, was resistant to ampicillin (10 mg) and was positive for catalase and oxidase. The major fatty acid was C18: 1ω7c (69%) with minor amounts of C19: 0 cyclo ω8c (8.9%), C16: 0 (6.9%), C12: 0 (5.7%) and C19: 1ω7c/ C19: 1ω6c (2.2%). Polar lipids of strain JC85T include two unidentified aminophospholipids (APL1,2), two unidentified phospholipids (PL1,2), phosphatidylcholine and four unidentified lipids (L1-4). Q-10 is the major quinone of strain JC85T. Based on polyphasic taxonomic analysis, strain JC85T represents a novel species for which, the name Rhizobium subbaraonis JC85T is proposed. The type strain is JC85T (=DSM 24765T=KCTC 23614T). © 2013 IUMS.

Naik M.T.,University Hyderabad | Sundar L.S.,University of Aveiro
Heat Transfer Engineering | Year: 2014

The article deals with the transition flow convective heat transfer and friction factor characteristics of water/propylene glycol-based CuO nanofluids flowing in a horizontal circular tube fitted with and without helical inserts. CuO nanoparticles of average particle diameter less than 50 nm were suspended in the base fluid and nanofluids of three different concentrations were prepared. Experiments were also conducted by inserting helical inserts having twist ratio in the range of 0 to 9 and Reynolds number ranging from 2500 to 10,000. The Nusselt number obtained with 0.5% concentration of CuO nanofluids is about 28% higher in a plain tube and is increased further up to 5.4 times over the base fluid when the helical insert with twist ratio 3 is used. In the plane tube the friction factor is increased by 10% and further enhanced to 140% with the usage of helical insert compared to the friction factor obtained with the base fluid alone. The friction factor penalty is very much less compared to the benefit of heat transfer enhancement. Correlations for predicting Nusselt number and friction factor are developed using the experimental data pertaining to CuO nanofluids in a plain tube with and without the helical inserts. © Taylor and Francis Group, LLC.

Sundar L.S.,University of Aveiro | Shusmitha K.,University Hyderabad | Singh M.K.,University of Aveiro | Sousa A.C.M.,University of Aveiro
International Communications in Heat and Mass Transfer | Year: 2014

The stable nanodiamond-nickel (ND-Ni) nanocomposite based magnetic nanofluids were prepared by dispersing them into water (W) and ethylene glycol (EG) without adding any surfactant and their electrical conductivity has been investigated experimentally. The nanocomposite was synthesized by an in-situ method and characterized by X-ray diffraction, micro-Raman, high-resolution transmission electron microscopy, and vibrating sample magnetometer. The electrical conductivity investigations were performed in very low particle concentrations of 0.02%, 0.05% and 0.1% in the temperature range from 24. °C to 65. °C. The results indicate that an anomalous increase in electrical conductivity was observed with an increase in particle loadings in both the base fluids of water and ethylene glycol. The enhancement values in electrical conductivity for 0.1% of water based ND-Ni nanofluid are 1339.81% and 853.15% at temperatures of 24. °C and 65. °C, respectively compared to water without particles. Similarly, the enhancement values in electrical conductivity for 0.1% of EG based ND-Ni nanofluid are 199.52% and 200.23% at temperatures of 24. °C and 65. °C, respectively compared to EG without particles. Conventional models, such as the Maxwell model and the Bruggeman correlation were considered for comparison and we observed disagreement. © 2014 Elsevier Ltd.

Darga Kumar N.,University Hyderabad | Narasimha Rao S.,Indian Institute of Technology Madras
Applied Ocean Research | Year: 2010

This investigation refers to an experimental study on earth pressure mobilization in caissons embedded in soft clay. Based on the results, a contiguous wall made up of embedded caissons in soft clay is proposed to serve as a coastal protection wall. Tests were conducted on model caissons embedded in stiff marine clay. Lateral load tests were carried out on models with embedment depth ratios of L/D=2,3 and 4 at load eccentricity ratios of e/D of 0.5, 1.0, 1.5 and 2.0. Earth pressure cells were embedded into the caissons at various depths. Using a pneumatic type of arrangement, controlled lateral loading was applied. The test results show that these caissons can be loaded to produce lateral deflection in the ratios of 30%-35% expressed in terms of diameter. The capacities are estimated corresponding to lateral deflection ratios of 20%. These results suggest that the lateral capacity is a function of undrained strength (su), embedment depth ratio (L/D) and load eccentricity ratio (e/D). There is a good correlation between lateral load and the maximum earth pressure mobilized. At a higher L/D ratio of 4, the lateral earth pressure is found to be unique function of lateral load irrespective of e/D. A unique relation is established between lateral load and deflection in the normalized form. This relation matches very well with the published field lateral load deflection curves. © 2010 Elsevier Ltd.

Shivali K.,University of Hyderabad | Sasikala C.,University Hyderabad | Ramana C.,University of Hyderabad
Systematic and Applied Microbiology | Year: 2012

Thirty-one members of the genus Marichromatium were analysed based on multilocus sequence analysis (MLSA) of four concatenated protein-coding genes (fusA, pufM, dnaK, recA) along with the internal transcribed spacer (ITS; 16S-23S rRNA) region and 16S rRNA gene. The restriction patterns obtained from the in silico analysis of the concatenated sequences were good barcodes for the identification of Marichromatium spp. Distinct phenotypic, chemotaxonomic and molecular differences allowed the separation of Marichromatium fluminis JA418T into a new genus in the family Chromatiaceae, for which we propose the name Phaeochromatium fluminis gen. nov. comb. nov. © 2012 Elsevier GmbH.

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