the physical adsorption of hydrogen sulfide and carbon dioxide gases on the zigzag (5,0) carbon nanotubes doped with nitrogen was investigated through the application of b3lyp/6-31g* at the level of theory on gaussian 03 software. a variety of stable and high abundance structures of nitrogen doped carbon nanotubes were considered in order to study the interaction between the mentioned gases in ...

The O2:CH4 ratio significantly effects nitrogen removal in mixed cultures where aerobic methane oxidation is coupled with denitrification (AME-D). The goal of this study was to investigate nitrogen removal of the AME-D process at four different O2:CH4 ratios [0, 0.05, 0.25, and 1 (v/v)]. In batch tests, the highest denitrifying activity was observed when the O2:CH4 ratio was 0.25. At this ratio...

Vegetative cells and heterocysts in the filamentous cyanobacterium Anabaena sp. PCC 7120 were observed by soft X-ray microscopy. Carbon-to-nitrogen (C/N) ratio of each cell was estimated by the difference of the absorbance of the images below and above the nitrogen K-edge absorption. It was revealed that the C/N ratios in vegetative cells and heterocysts are 4.54 and 2.46, respectively.

We found that concentrations of nitrogen (N) in the stomach of voles varied between forest sites. Concentrations of nitrogen as well as the ratio of nitrogen to carbon (C) in stomach content were not different between the sexes or with season. Body mass varied between sites and between seasons but were unrelated to N concentration in spite that the body mass of voles in the spring season were o...

Though carbon (C): nitrogen (N) stoichiometry has been widely studied in terrestrial ecosystems, little is known about its variation following afforestation. By synthesizing the results of 53 studies, we examined temporal and spatial variation in C: N ratios and in N-C scaling relationships of both the organic and the mineral soil horizons. Results showed that C: N ratios remained constant in t...

Grasslands have a long history of invasion by exotic annuals, which may alter microbial communities and nutrient cycling through changes in litter quality and biomass turnover rates. We compared plant community composition, soil chemical and microbial community composition, potential soil respiration and nitrogen (N) turnover rates between invaded and restored plots in inland and coastal grassl...

The objective of this work was to study the effects of tillage and liquid manure applications on some physical and chemical properties as well as on the carbon and nitrogen mineralization potential of a meadow soil. Our results indicated that tillage and manure applications had no effect on the concentration of Cu, Mn, total N and organic C in 0-15 cm layer of soil after 15 years of treatment. ...

A pilot-scale modified Orbal oxidation ditch with internal recycle of the nitrified liquor was developed to significantly enhance total nitrogen (TN) removal through simultaneous nitrification/denitrification (SND) coupled with pre-denitrification under the aerated-anoxic condition. Long-term operational results showed that the highest TN removal efficiency was achieved at very low dissolved ox...