Conversion Of Nitrogen Dioxide Research Articles

Testing of an Integrated Nitrogen Oxide Catcher

A gas-purification system with maximum capacity 50 m3/h was developed, fabricated, and tested to catch nitrogen oxides released during hydrometallurgical processing of spent fuel from the BREST reactor. To catch nitrogen oxides, the setup employs water aerosols introduced into the gas duct; it also includes a tank for mixing water aerosols with gas flow, coarse and fine filters, and BRUNS and SMOG apparatus. The filtering complex (mixing tank, FCGO and FAROS filters) gave 72–76% conversion of nitrogen dioxide with initial concentration of 11 g/m3; this confirmed that aerosol fiberglass filters can be used to catch nitrogen dioxide. In the tests, the complex of units comprising the setup gave 95.4–98.5% conversion of nitrogen oxide with initial concentration 11–50 g/m3. After the design of the mixing tanks is improved and remote extraction of the cartridges of the gas purification apparatus is organized, the tested gas purification setup can be used in radiochemical production.

Effect of Acclimation to Intermittent Hypobaric Hypoxia on NO Homeostasis

Hypoxia is one of the major stimuli to produce nitric oxide (NO). Recent studies have shown that conversion of nitrogen dioxide (NO2) to NO is independent of nitric oxide synthase (NOS) activity, and exercise is responsible for NO production by its reduction of metabolic products NOx, nitrite (NO2−)/nitrate (NO3−). This study was to examine the effects of training on NO homeostasis after high altitude exposure.Aerobic capacity (i.e., VO2max) and NO related molecules, cyclic guanosine monophosphate (cGMP), NOx or NO2, were measured by use of an fluorometric and enzyme immunoassay (EIA) analysis (Cayman Inc., USA) from bloods: Fourteen healthy exercisers comparatively corresponding to mountaineers during high‐intensity aerobic exercise who has climbed up 5,000 meters above the sea level, and volunteers who had 7 days before and after aerobic training on treadmill and bicycle ergometer based on 75% HR max and sleeping in hypobaric hypoxic conditions (3000m~5000m) for 4 days.VO2/75%HRmax of acclimation at an altitude of 5,000 meters was significantly increased by 21.45% (p = 0.0016). In addition, cGMP concentration in post‐training group (3.35 ± 1.082 pmol/ml) was also increased compared to pre‐training one (1.54 ± 0.751 pmol/ml) (p < 0.001), whereas NOx or NO2 concentration was decreased significantly (i.e., NOx, 16.49 ± 6.357 vs. 11.32 ± 2.805 μM, p = 0.0027; NO2, 12.62 ± 8.321 vs. 7.39 ± 2.273 nM, p = 0.0395) These findings suggest that increase of cGMP via an NO production may ameliorate physical activity at high altitudes, which is associated with the changes of systemic concentration of NOx and NO2.

Particulate matter characteristics during agricultural waste burning in Taichung City, Taiwan

Agricultural waste burning is performed after harvest periods in June and November in Taiwan. Typically, farmers use open burning to dispose of excess rice straw. PM 2.5 and PM 2.5–10 measurements were conducted at National Chung Hsing University in Taichung City using a dichotomous sampler. The sampling times were during straw burning periods after rice harvest during 2002–2005. Ionic species including SO 4 2−, NO 3 −, NH 4 +, K +, Ca 2+, Cl − and Na + and carbonaceous species (EC and OC) in PM 2.5 and PM 2.5–10 were analyzed. The results showed that the average PM 2.5 and PM 2.5–10 concentrations were 123.6 and 31.5 μg m −3 during agricultural waste burning periods and 32.6 and 21.4 μg m −3 during non-waste burning periods, respectively. The fine aerosol ionic species including Cl −, K + and NO 3 − increased 11.0, 6.7 and 5.5 times during agricultural burning periods compared with periods when agricultural waste burning is not performed. K + was found mainly in the fine mode during agricultural burning. High nitrogen oxidation ratio was found during agricultural waste burning periods which might be caused by the conversion of Nitrogen dioxide (NO 2) to NO 3 −. It is concluded that agricultural waste burning with low dispersion often causes high PM 2.5 and gases pollutant events.

Chemiluminescent gas analyzers

Theoretical and experimental studies are reported on the chemiluminescent interactions of nitric oxide, and the hydrides of arsenic and phosphorus with ozone, as well as on the thermal conversion of nitrogen dioxide and ammonia into nitric oxide. Chemiluminescent analyzers have been developed for monitoring atmospheric air, air in working areas, and gas discharges.

Conversion of nitrogen dioxide, nitric acid, and n-propyl nitrate to nitric oxide by a gold-catalyzed reduction with carbon monoxide

A new technique is described for the real-time, quantitative conversion of several XNO/sub 2/ compounds to NO, where X denotes a radical group. The technique utilizes the reduction of these compounds by CO at heated gold catalyst to yield NO. The NO product was detected by a sensitive chemiluminescence detector. The technique was demonstrated to convert NO/sub 2/, HNO/sub 3/, and n-propyl nitrate quantitatively to NO for mixing ratios in the range of 1-120 ppbv in synthetic air at atmospheric pressure. Conversion results were obtained for CO mixing ratios in the range of 0.2-1000 ppmv and for temperatures in the range of 20-600 /sup 0/C. The Gormley-Kennedy equation was used to analyze the results for consistency with known diffusion coefficients. The CO reduction process is discussed in terms of the thermochemistry of the net conversion reactions and catalytic properties of the gold surface. In addition, the potential of this technique for atmospheric measurements is noted. 8 figures, 3 tables.