Nitrates ambient concentrations

Thompson, C. R., and G. Kats. Effects of ambient concentrations of peroxyacetyl nitrate on navel orange trees. Environ. Sci. Technol. 9 35-38, 1975. 

Rees, A., Woodward, M., and Joint, I. (1999a). Measurement of nitrate and ammonium uptake at ambient concentrations in oligotrophic waters of the north-east Atlantic Ocean. Mar. Ecol. Prog. Ser. 187, 295-300. 

Figure ll.ll Results from a set of in situ nutrient addition bioassays conducted at three locations along the axis of the Neuse River Estuary that was routinely monitored for ambient nutrient (ammonium, nitrate, phosphate) concentrations and chlorophyll a as an indicator phytoplankton biomass. All nitrogen forms were added at 20 jlM-N, while phosphate was added at 5 pM-P. The locations of bioassays are shown (symbols) on the map (A) just upstream of the chlorophyll a maximum (Cniax)l ( ) the Cmax i d (C) downstream of the Cmax- Strong N limitation was encoun-... 

In 1986, Teramoto et al. [56] reported a series of experiments on the permeation of ethylene and ethane through supported liquid membranes containing silver nitrate (AgNO3) aqueous solutions at ambient temperature. It was found the highest selectivity for ethylene over ethane of approximately 1000 when sUver nitrate (AgNO3) concentration was 4 mol/dm and an ethylene permeabihty of 3 x 10 barrer/cm. However, the selectivity was lost in about 200 min. 

It seems possible that other well-known nitro esters might also be effective. Indirect nitration of phenol in ether/water (1 1) by the addition of sodium nitrate and concentrated (11M) hydrochloric ackJ and stirring of the mixture at ambient temperature for more than 12 hours gave the isomeric 2- and 4-nitrophenols in 65% yield with the ratio 3 2 respectively (ref.62). Although this percentage of products is the same as in standard laboratory methods the conditions are essentially milder. 

CMB Application to Central California PM Chow et al. (1992) apportioned source contributions to aerosol concentrations in the San Joaquin Valley of California. The source profiles used for CMB application are shown in Table 26.1. The standard deviations oa.. of the profiles (three or more samples were taken) are also included. To account for secondary aerosol components in the CMB calculations, ammonium sulfate, ammonium nitrate, sodium nitrate, and organic carbon were expressed as secondary source profiles using the stoichiometry of each compound. The average elemental concentrations observed at one of the receptors—Fresno, California, in 1988-1989— are shown in Table 26.2. The ambient concentrations of some species (c.g., Ga, As, Y, Mo, Ag) included in the source profiles were below the detection limits. These species... 

In addition due to inadequate methods for in situ analysis at ambient concentrations analysis of airborne particles in their various forms has been limited. Even if the aerosols are analysed in detail changes have been found to occur in aerosol composition when collected by filters as they tend to react with the filter material itself. Therefore not only is improved identification of sulphate and nitrate speciation reaction mechanisms required but also improved techniques for in situ analysis to facilitate greater understanding of the quantitative aspects of the atmosphere which play a fundamental role in the long range transport of these pollutants. 

All other dangerous reactions consist of oxidations of bismuth by strong oxidants. Thus, chloric and perchloric acids lead to highly sensitive explosives (probably bismuth chlorate and perchlorate). Fuming nitric acid causes the incandescence of bismuth at ambient temperature whereas a detonation occurs when molten bismuth is mixed with concentrated nitric acid. Rnally, a bismuth/molten ammonium nitrate mixture causes a very violent or even an explosive reaction. 

In 2007, Dickson et al. found that it is possible to stain fixed cells with fluorescent silver clusters instead of silver nanoparticles by tuning the staining conditions [57]. The new approach consists of staining fixed cells with a low concentrated silver nitrate solution 20-100 mM, within 20 h at ambient conditions, and reducing the silver by photoactivation, with the result of small silver clusters that present a broad emission band between 500 and 700 nm (Fig. 8a-d). The discovery that fluorescent silver clusters can be generated by photoactivation of cells fed with silver salt, opens up new paths for the application of silver clusters in biological systems. 

An unusual feature of the KA-process is that the reaction is conducted at 60-80 °C. Solutions of nitric acid in acetic anhydride are known to be prone to dangerous fume off at temperatures above ambient. However, a saturated solution of ammonium nitrate in fuming nitric acid can be added to warmed acetic anhydride without such danger. In fact, these reactions are commonly conducted at 60-80 °C as a matter of safety by preventing a build-up of unreacted starting material. The hexamine used in these reactions is in the form of the dinitrate salt, which is formed as a crystalline salt on addition of a saturated aqueous solution of hexamine to concentrated nitric acid below 15 °C. The use of hexamine dinitrate in this process reduces the amount of nitric acid needed for the nitrolysis. 

Wilson, N. K., T. R. McCurdy, and J. C. Chuang, Concentrations and Phase Distributions of Nitrated and Oxygenated Polycyclic Aromatic Hydrocarbons in Ambient Air, Atmos. Environ., 29, 2575-2584 (1995). 

Potassium salts are known to act as suppressants of spontaneous ignition of hydrocarbon flames arising from interdiffusion with ambient air. It has been reported that potassium salts act to retard the chemical reaction in the flames of nitropolymer propellants. Two types of potassium salts used as plume suppressants are potassium nitrate (KNO3) and potassium sulfate (K2SO4). The concentration of the salts is varied to determine their region of effectiveness as plume suppressants. 

Several formal and informal intercomparisons of nitric acid measurement techniques have been carried out (43-46) these intercomparisons involve a multitude of techniques. The in situ measurement of this species has proven difficult because it very rapidly absorbs on any inlet surfaces and because it is involved in reversible solid-vapor equilibria with aerosol nitrate species. These equilibria can be disturbed by the sampling process these disturbances lead to negative or positive errors in the determination of the ambient vapor-phase concentration. The intercomparisons found differences of the order of a factor of 2 generally, and up to at least a factor of 5 at levels below 0.2 ppbv. These studies clearly indicate that the intercompared techniques do not allow the unequivocal determination of nitric acid in the atmosphere. A laser-photolysis, fragment-fluorescence method (47) and an active chemical ionization, mass spectrometric technique (48) were recently reported for this species. These approaches may provide more definite specificity for HN03. Challenges clearly remain in the measurement of this species. 

Nitro-6-methyl-4//-pyrido[l,2-a]pyrimidin-4-one was prepared from 6-methyl-4//-pyrido[l,2-a]pyrimidin-4-one by nitration with a mixture of concentrated nitric and sulfuric acids at ambient temperature for 2 hours (85JHC481). 

Wilson, N.K., T.R. McCurdy, and J.C. Chuang. 1995. Concentrations and phase distributions of nitrated and oxygenated polycyclic aromatic hydrocarbons in ambient air. Atmos. Environ. 29 2575-2584. 

Oxidized forms of DIN (NC>3 and NO2-) must also be converted into ammonia by either nitrate or nitrate reductases before being fixed into organic matter. Similarly, there is a nitrogenase reductase reaction involved in the fixation of N2. The range of fractionation observed with NC>3 assimilation is similar to that observed with NH4+, with more fractionation (by diatoms) occurring with higher ambient NO3 concentrations (Wada and Hattori, 1978). Active transport of NC>3 has been observed by marine diatoms however, details of the membrane-bound enzyme involved with this reaction remain unclear (Falkowski, 1975 Packard, 1979). 

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