Nitrate distributions

Figure 18 Simulated uptake of nitrate from a "patchy soil. The relative nitrate distribution from held data is shown in D. In A, the plant roots were allowed to respond in a plastic fashion to local resource availability while B shows the nonplastic response both plots show the relative nitrate uptake over the 0.5m area C. The total nitrate acquired in each plot. Pla-stic roots acquired 61% more nitrate during the 2-day simulation, (From Ref. 88.)...

Anderson et al. (1980) worked on nitrate distribution in the Karup Basin,... 

Trade name of a cartridged powder-form explosive containing ammonium nitrate distributed in Austria by DYNAMIT NOBEL WIEN. 

Bianchi, M., Fehatra, Treguer, P., Vincendeau, M. A., and Morvan, J. (1997). Nitrification rates, ammonium and nitrate distribution in upper layers of the water column and in sediments of the Indian sector of the Southern Ocean. Deep-Sea Research 44, 1017—1032. 

Anderson, J.J., Okubo, A., Robbins, A. S., and Richards, F. A. (1982). A model for nitrite and nitrate distributions in oceanic oxygen minimum zones. 

Nitrate distribution and the nutrient-rich surface regions... 

These analyses, combined with data from in situ sensors, provide information on small-scale and mesoscale features not otherwise available. Signals in the sample stream are modified by passage through the hose. This modification and time delays introduced by analysis must be considered in sampling strategy and data management approaches. This system has been used to determine nutrients, in vivo fluorescence, and temperature in a warm core ring. Examples of the results are provided the fluorescence, temperature, and nitrate distributions show considerable independence. 

Johnston CT, Cook PG, Frape SK, Plummer LN, Busenberg E, Blackport RJ (1998) Ground water age and nitrate distribution within a glacial aquifer beneath a thick unsaturated zone. Ground Water 36 171-180... 

Rawahy S, Larson DL, Walworth J, Slack DC. (2003). Effect of an electrical input with drip irrigation on nitrate distribution in soil. Applied Engineering in Agriculture 19 55-58. 

Again the uncertainty about the proportion of an observed result which is due to nitration and the proportion which is due to nitrosation exists. Thus, in expt. 11 phenol was being nitrated above the encounter rate and the observed isomer distribution could arise from a combination of nitration by whatever is the usual electrophile with nitration by a new, less reactive electrophile, or with nitrosation, or all three processes could be at work. 

The nitration of some substituted nitrobenzenes has been studied in connection with the high o -ratios produced by [ —/ — A/] substituents. Thus nitration in sulphuric acid of 2,5-dialkyl-nitrobenzenes produces the isomer distributions shown below. As has been seen ( 9.1.3), one explanation for the occurrence of high o -ratios with [-/—A/] substituents is that the latter specifically deactivate para positions. In the... 

Some work has been done on the nitration of polyphenyls the case of -terphenyl presents problems in connection with isomer distributions similar to those met with that of biphenyl. 

The nitration of phenylpyridines and related compounds has attracted attention for a long time, and measurements of isomer proportions have been made for several compounds of this type. Nitration occurs in the phenyl ring. For 2-phenylpyridine and 2-phenylpyridine i-oxide measurements of the dependence of rate of nitration upon acidity in 75-81 % sulphuric acid at 25 °C show that both compounds are nitrated as their cations (table 8.1). The isomer distribution did not depend significantly upon the acidity, and by comparison with the kinetic data for quinolinium ( 10.4.2) the partial rate factors illustrated below were obtained.They should be compared with those for the nitration of 2-nitrobiphenyl ( 10.1). The protonated heterocyclic groups are much... 

TABLE in-46. ISOMER DISTRIBUTION OBTAINED DURING THE NITRATION OF PHEN YL-THIA20LES (250)... 

Urea processes provide an aqueous solution containing 70—87% urea. This solution can be used directiy for nitrogen-fertilizer suspensions or solutions such as urea—ammonium nitrate solution, which has grown ia popularity recentiy (18). Urea solution can be concentrated by evaporation or crystallization for the preparation of granular compound fertilizers and other products. Concentrated urea is sohdified ia essentially pure form as prills, granules, flakes, or crystals. SoHd urea can be shipped, stored, distributed, and used mote economically than ia solution. Furthermore, ia the soHd form, urea is more stable and biuret formation less likely. 

Mixed with additives, urea is used in soHd fertilizers of various formulations, eg, urea—ammonium phosphate (UAP), urea—ammonium sulfate (UAS), and urea—phosphate (urea + phosphoric acid). Concentrated solutions of urea and ammonium nitrate (UAN) solutions (80—85 wt%) have a high nitrogen content but low crystallization point, suitable for easy transportation, pipeline distribution, and direct spray appHcation. 

Chemical composition data for CPM and FPM for a variety of locations are summarized in Table 5. These data illustrate several important points. First, the distributions of the PM q between CPM and FPM vary from about 0.4 to 0.7. Second, the ratio of PM q to TSP varies from 0.58 to 0.79. In general, both this ratio and the ratio of FPM to PM q tend to be higher at mral sites, but Bermuda, because of the large influence of sea salt in the CPM, is an exception. Sulfate (SO ), carbon (as organic carbon, OC, and elemental carbon, EC), and nitrate (NO3 ) compounds generally account for 70—80% of the FPM. In the eastern United States, compounds are the dominant species, although very Httie is emitted directiy into the atmosphere. Thus... 

Calcium. Calcium is the fifth most abundant element in the earth s cmst. There is no foreseeable lack of this resource as it is virtually unlimited. Primary sources of calcium are lime materials and gypsum, generally classified as soil amendments (see Calcium compounds). Among the more important calcium amendments are blast furnace slag, calcitic limestone, gypsum, hydrated lime, and precipitated lime. Fertilizers that carry calcium are calcium cyanamide, calcium nitrate, phosphate rock, and superphosphates. In addition, there are several organic carriers of calcium. Calcium is widely distributed in nature as calcium carbonate, chalk, marble, gypsum, fluorspar, phosphate rock, and other rocks and minerals. 

Therefore the extent of extraction or back-extraction is governed by the concentration of X ia the aqueous phase, the distribution coefficients, and selectivities depending on the anion. In nitrate solutions, the distribution coefficient decreases as the atomic number of the REE increases, whereas ia thiocyanate solutions, the distribution coefficient roughly increases as the atomic number of the REE increases. The position of yttrium in the lanthanide series is not the same in nitrate and thiocyanate solutions, and this phenomenon has been used for high purity yttrium manufacture in the past. A combination of extraction by carboxyUc acids then by ammonium salts is also utilized for production of high purity yttrium. 

The only method utilized commercially is vapor-phase nitration of propane, although methane (70), ethane, and butane also can be nitrated quite readily. The data in Table 5 show the typical distribution of nitroparaffins obtained from the nitration of propane with nitric acid at different temperatures (71). Nitrogen dioxide can be used for nitration, but its low boiling point (21°C) limits its effectiveness, except at increased pressure. Nitrogen pentoxide is a powerful nitrating agent for alkanes however, it is expensive and often gives polynitrated products. 

The distribution of highly extractable solutes such as and Pu between the aqueous and organic phases is strongly dependent upon the nitrate anion concentration in the aqueous phase. This salting effect permits extraction or reextraction (stripping) of the solute by controlling the nitric acid concentration in the aqueous phase. The distribution coefficient, D, of the solute is expressed as... 

Homogeneous Aqueous Reactors. As a part of the research on neutron multiphcation at Los Alamos in the 1940s, a small low power reactor was built using a solution of uranium salt. Uranyl nitrate [36478-76-9] U02(N0 2> dissolved in ordinary water, resulted in a homogeneous reactor, having uniformly distributed fuel. This water boiler reactor was spherical. The 235u... 

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