Effects of H2 and H preferential diffusion and unity Lewis number on superadiabatic flame temperatures in rich premixed methane flames

Peer reviewed: YesNRC publication: Ye

Non-grey gas radiative transfer analyses using the statistical narrow-band model

Peer reviewed: YesNRC publication: Ye

Soot formation and temperature field structure in laminar propane-air diffusion flames at elevated pressures

Peer reviewed: YesNRC publication: Ye

An accurate efficient and flexible SNBCK-based unified band model for calculations of spectrally resolved and integrated quantities in participating media containing real gases

Peer reviewed: YesNRC publication: Ye

Numerical investigation of the effects of a skimmer on the structure of dense sprays

Peer reviewed: YesNRC publication: Ye

Numerical study of breakup processes of water jet injected into a cross air flow

Peer reviewed: YesNRC publication: Ye

Effects of gas and soot radiation on soot formation in a coflow laminar ethylene diffusion flame

A computational study of soot formation in an undilute axisymmetric laminar ethylene-air coflow jet diffusion flame at atmospheric pressure was conducted using a detailed gas-phase reaction mechanism and complex thermal and transport properties. A simple two-equation soot model was employed to predict soot formation, growth, and oxidation with interactions between the soot chemistry and the gas-phase chemistry taken into account. Both the optically thin model and the discrete-ordinates method coupled with a statistical narrow-band correlated-K based wide band model for radiative properties of CO, CO\u2082, H\u2082O, and soot were employed in the calculation of radiation heat transfer to evaluate the adequacy of using the optically thin model. Several calculations were performed with and without radiative transfer of radiating gases and/or soot to investigate their respective effects on the computed soot field and flame structure. Radiative heat transfer by both radiating gases and soot were found to be important in this relatively heavily sooting flame studied. Results of the optically thin radiation model are in good agreement with those obtained using the wide band model except for the flame temperature near the flame tip.)Peer reviewed: YesNRC publication: Ye

Influence of Pressure on Soot Formation in Laminar Diffusion Flames of Methane-Air up to 40 bar

Peer reviewed: YesNRC publication: Ye

Investigation of the Soot Formation in Ethylene Laminar Diffusion Flames When Diluted with Helium or Supplemented by Hydrogen

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Energy and Fuels, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/ef401970qA new optical diagnostic technique has been used to measure the spatially distributed temperatures, soot diameters, and soot volume fractions in several different ethylene laminar diffusion flames to investigate the effect of adding hydrogen and helium on the soot formation. The test results show that adding hydrogen increases the flame temperature in all regions, while adding helium does not significantly affect the flame temperature in the reaction region but does increase the flame temperature elsewhere. The flame heights when adding helium and hydrogen can be calculated using the correlation introduced by Roper if the ethylene diffusion coefficient is used. This indicates that the flame height is determined by the diffusion of ethylene molecules when the hydrogen fraction is below 20%. It was also found that either adding helium or hydrogen does not significantly affect the soot diameter but does reduce the soot volume fraction. A total of 20% of helium addition by volume was measured to reduce the total soot number by 19%, while a total of 20% of hydrogen addition reduced the total soot number by 23%. In comparison, replacing the hydrocarbon with hydrogen is much more effective in reducing soot formation. Replacement of 25% ethylene by hydrogen was measured to reduce the total soot number by 66%. Apart from demonstrating the influence of hydrogen and helium on ethylene diffusion flames, these measurements provide additional data for modelers of diffusion flames, especially those with an interest in the formation of particulate matter. © 2014 American Chemical Society

The Kolumbo submarine volcano of Santorini island is a large pool of bacterial strains with antimicrobial activity

Microbes in hydrothermal vents with their unique secondary metabolism may represent an untapped potential source of new natural products. In this study, samples were collected from the hydrothermal field of Kolumbo submarine volcano in the Aegean Sea, in order to isolate bacteria with antimicrobial activity. Eight hundred and thirty-two aerobic heterotrophic bacteria were isolated and then differentiated through BOX-PCR analysis at the strain level into 230 genomic fingerprints, which were screened against 13 different type strains (pathogenic and nonpathogenic) of Gram-positive, Gram-negative bacteria and fungi. Forty-two out of 176 bioactive-producing genotypes (76 %) exhibited antimicrobial activity against at least four different type strains and were selected for 16S rDNA sequencing and screening for nonribosomal peptide (NRPS) and polyketide (PKS) synthases genes. The isolates were assigned to genus Bacillus and Proteobacteria, and 20 strains harbored either NRPS, PKS type I or both genes. This is the first report on the diversity of culturable mesophilic bacteria associated with antimicrobial activity from Kolumbo area; the extremely high proportion of antimicrobial-producing strains suggested that this unique environment may represent a potential reservoir of novel bioactive compounds