Mass Spectrometric Detection of Ionic and Neutral Species During Highly Preheated Air Combustion by Alkali Element Ion Attachment

2002 ◽  
Vol 124 (4) ◽  
pp. 749-756 ◽  
Author(s):  
T. Ishiguro ◽  
A. Matsunami ◽  
K. Matsumoto ◽  
K. Kitagawa ◽  
N. Arai ◽  
...  
Keyword(s):  
Oxygen Concentration ◽  
Chemical Species ◽  
Ionic Species ◽  
Combustion Mechanism ◽  
Low Oxygen ◽  
Neutral Species ◽  
Alkali Element ◽  
Compact Size ◽  
Ion Attachment ◽  
Low Oxygen Concentration

The use of high temperature and low oxygen concentration air as the oxidizer for regenerative combustion has become of increasing interest because this technology results in higher thermal efficiency, low energy consumption, and reduced emission of pollutants, such as NOx and CO2, and compact size of the equipment. In this study information is provided on the effect of preheating the low oxygen concentration air on the formation and detection of chemical ions and neutral species formed in flames. These ions and species were detected directly using mass spectrometry. Such information also assists in determining the combustion mechanism. The intact ionic species have been detected only at downstream position of the flames. By applying an alkali element Li+ ion attachment technique, neutral species, such as Li+-attached ions have been also detected successfully. Three specific flame cases have been examined. They include using normal air (flame I), preheated air (flame II), and preheated air with low (diluted) oxygen concentration in air (flame III). The results show significant change in the spectra of the intact ionic species and the Li+-adduct neutral species amongst the three flames. The results also show that preheating the combustion air increases the number of chemical species formed in the flames. However, these chemical species decrease with low oxygen concentration (diluted) combustion air.

Effect of low oxygen concentration on activation of inflammation by Helicobacter pylori

2021 ◽  
Vol 560 ◽  
pp. 179-185
Author(s):  
Adiza Abass ◽  
Tokuju Okano ◽  
Kotchakorn Boonyaleka ◽  
Ryo Kinoshita-Daitoku ◽  
Shoji Yamaoka ◽  
...  
Keyword(s):  
Helicobacter Pylori ◽  
Oxygen Concentration ◽  
Low Oxygen ◽  
Low Oxygen Concentration

The Constant Low Oxygen Concentration in All the Target Cells for Mouse Tail Radionecrosis

1982 ◽  
Vol 92 (1) ◽  
pp. 172 ◽  
Author(s):  
J. H. Hendry ◽  
J. V. Moore ◽  
B. W. Hodgson ◽  
J. P. Keene
Keyword(s):  
Oxygen Concentration ◽  
Target Cells ◽  
Low Oxygen ◽  
Low Oxygen Concentration

scholarly journals Zooplankton fluctuations in Jurumirim Reservoir (São Paulo, Brazil): a three-year study

2009 ◽  
Vol 69 (1) ◽  
pp. 1-18 ◽  
Author(s):  
LP. Sartori ◽  
MG. Nogueira ◽  
R. Henry ◽  
EM. Moretto
Keyword(s):  
Water Column ◽  
Oxygen Concentration ◽  
Retention Time ◽  
Sao Paulo ◽  
Seasonal Effect ◽  
São Paulo ◽  
Low Oxygen ◽  
High Concentration ◽  
Heterogeneous Distribution ◽  
Low Oxygen Concentration

During three consecutive years, monthly samples of zooplankton were taken in the lacustrine (dam) zone of Jurumirim (São Paulo, Brazil). The seasonal effect on basic limnological features (thermal regime, oxygen distribution, phytoplankton biomass, etc.) was also examined. The influence of the seasonality on the fluctuation of the zooplankton composition and abundance was not clearly detected (low degree of recurrent patterns). Rotifers (32 taxa) were the most abundant organisms during almost the entire study period with some seasonal alternations in the maximum abundance peaks of the main taxa (Conochilus unicornis, Keratella americana, K. cochlearis and Hexarthra spp.), except for Polyarthra (mainly P. vulgaris). Only occasionally copepods were numerically dominant. Higher copepod abundance was positively associated to periods of increase in the water retention time. Among the Copepoda (10 taxa) the calanoids (mainly Notodiaptomus iheringi) were more abundant, especially in warmer periods. Conversely, cyclopoids had higher abundance in autumn and winter. The species Thermocyclops minutus and T. decipiens co-occurred, but the first attained higher abundance. Some evidence of co-existence strategies between both species are considered. Cladocera (17 taxa) was never numerically dominant and the main taxa (Bosmina spp., Ceriodaphnia spp. and Diaphanosoma spp.) occurred almost the whole study period and did not present a seasonal pattern of fluctuation. Diaphanosoma (mainly D. birgei) attained the highest abundance among cladocerans. Most organisms were always found at the surface, but they also occupy the whole water column, even in periods of stratified conditions and low oxygen concentration in the bottom layers. Among the main zooplanktonic taxa, only Hexarthra avoids deep layers. An exceptionally high concentration of Copepoda nauplii on the surface was influenced by low transparency, high concentration of phytoplankton at this layer and low oxygen concentration at the bottom. In periods of higher retention timevariability there was a more heterogeneous distribution of the zooplankton in the water column. The increase in the retention time seems also to favor the copepod development. Finally, some inter-decade changes are considered on the basis of zooplankton assemblage structure observations.

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