atomic nitrogen
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2021 ◽  
Author(s):  
Daniel Palmquist ◽  
Vijay Gopal ◽  
Luca Maddalena
Keyword(s):  

ACS Omega ◽  
2021 ◽  
Author(s):  
Yuto Tsuchida ◽  
Naoya Murakami ◽  
Tatsuya Sakakura ◽  
Yoshiyuki Takatsuji ◽  
Tetsuya Haruyama

2021 ◽  
Author(s):  
Nikolaos Gougoulias ◽  
George Papapolymerou ◽  
Anastasios Mpesios ◽  
Dorothea Kasiteropoulou ◽  
Maria N. Metsoviti ◽  
...  

Abstract The aim of this work was to investigate the kinetics of the heterotrophic growth of Chlorella vulgaris as a means of producing bio-oil for biodiesel production. Glycerol was used as the sole organic carbon substrate. Anaerobic digestrate from a local plant was used to examine its effect on the kinetics and the protein and lipid content of the biomass. The effect of the initial carbon and nitrogen concentrations on the carbon uptake rate was studied independently. In one set of five experiments the organic carbon in the form of glycerol, varied from 0.27 g L-1 to 5.36 g L-1 while the concentration of atomic nitrogen was held constant and equal to 45.4 mg L-1. The Co/No ratio varied from 6 to 118.1. In a second set, also of five experiments, the organic carbon was held constant and equal to 3.3 g L-1 and atomic nitrogen varied from 22.7 mg L-1 to 450 mg L-1. The Co/No ratio varied from 7.3 to 145.4. In a third set of experiments anaerobic digestrate was added in increasing amounts into the culture media from 4% to 16%. It was found that the carbon uptake rate as well as the lipid and protein content depended on the Co/No ratio. Increasing ratios of Co/No lead to higher carbon uptake rates, higher lipid content and lower protein content. The initial nitrogen concentration was also found to affect the growth rate of C. vulgaris. The addition of anaerobic digestrate did not affect appreciably the protein and lipid content of the biomass while, addition of anaerobic digestrate up to 16% in the culture medium increased the carbon uptake rate up to about 24%.


2021 ◽  
Vol 254 ◽  
pp. 01005
Author(s):  
Vasily Bychkov ◽  
Ilia Seredkin ◽  
Alexei Dmitriev

An analysis of the Kamchatka lidar station data obtained in January-February 2021 is presented. Pronounced light scattering layers at altitudes of 300 km have been detected. Layers at these heights appear during precipitation of electrons with energies of about 300 eV. Analysis of the lidar data showed that increased light scattering was observed at the heights of the mesosphere, accompanied by an increase in the ionospheric parameter fmin. It was concluded that the observed aerosol formations in the mesopause region could be caused by precipitation of charged particles with energies of ∼ 500 keV. Aerosol formations in the area of 60-75 km should be recognized as imaginary. This is a manifestation of resonant scattering by excited ions of atomic nitrogen


2020 ◽  
Author(s):  
Sharma Yamijala ◽  
Giorgio Nava ◽  
Zulfikhar A. Ali ◽  
Davide Beretta ◽  
Bryan Wong ◽  
...  

By combining experimental measurements with <i>ab initio</i> molecular dynamics simulations, we provide the first microscopic description of the interaction between metal surfaces and a low-temperature nitrogen-hydrogen plasma. Our study focuses on the dissociation of hydrogen and nitrogen as the main activation route. We find that ammonia forms via an Eley-Rideal mechanism where atomic nitrogen abstracts hydrogen from the catalyst surface to form ammonia on an extremely short timescale (a few picoseconds). On copper, ammonia formation occurs via the interaction between plasma-produced atomic nitrogen and the H-terminated surface. On platinum, however, we find that surface saturation with NH groups is necessary for ammonia production to occur. Regardless of the metal surface, the reaction is limited by the mass transport of atomic nitrogen, consistent with the weak dependence on catalyst material that we observe and has been reported by several other groups. This study represents a significant step towards achieving a mechanistic, microscopic-scale understanding of catalytic processes activated in low-temperature plasma environments.


2020 ◽  
Author(s):  
Sharma Yamijala ◽  
Giorgio Nava ◽  
Zulfikhar A. Ali ◽  
Davide Beretta ◽  
Bryan Wong ◽  
...  

By combining experimental measurements with <i>ab initio</i> molecular dynamics simulations, we provide the first microscopic description of the interaction between metal surfaces and a low-temperature nitrogen-hydrogen plasma. Our study focuses on the dissociation of hydrogen and nitrogen as the main activation route. We find that ammonia forms via an Eley-Rideal mechanism where atomic nitrogen abstracts hydrogen from the catalyst surface to form ammonia on an extremely short timescale (a few picoseconds). On copper, ammonia formation occurs via the interaction between plasma-produced atomic nitrogen and the H-terminated surface. On platinum, however, we find that surface saturation with NH groups is necessary for ammonia production to occur. Regardless of the metal surface, the reaction is limited by the mass transport of atomic nitrogen, consistent with the weak dependence on catalyst material that we observe and has been reported by several other groups. This study represents a significant step towards achieving a mechanistic, microscopic-scale understanding of catalytic processes activated in low-temperature plasma environments.


ACS Omega ◽  
2020 ◽  
Vol 5 (41) ◽  
pp. 26776-26785
Author(s):  
Atsushi Tanide ◽  
Shohei Nakamura ◽  
Akira Horikoshi ◽  
Shigeru Takatsuji ◽  
Takahiro Kimura ◽  
...  

2020 ◽  
Vol 27 (11) ◽  
pp. 2050013
Author(s):  
RAFAŁ LEWANDKÓW ◽  
RADOSŁAW WASIELEWSKI ◽  
PIOTR MAZUR

The growth and stability of hafnium films on [Formula: see text]-GaN(0001) surface with native oxide was investigated with X-ray and ultraviolet photoelectron spectroscopy (XPS, UPS). It is shown that hafnium creates a continuous and stable layer on GaN substrate. Thermal treatment at [Formula: see text]C of Hf/GaN system causes decomposition of GaN and reaction of hafnium with atomic nitrogen from the substrate. XPS spectra demonstrate the reaction by a strong shift of the N 1s and Hf 4f lines. An attempt for bringing on the same reaction with molecular nitrogen under pressure of [Formula: see text] mbar was not successful. UPS spectra show a metallic character of the hafnium adlayer in such instances.


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