Nitrogen Ratio

Essential for synthesis considerations is the abiUty to determine the amount of ammonia present ia an equiUbrium mixture at various temperatures and pressures. ReHable data on equiUbrium mixtures for pressures ranging from 1,000 to 101,000 kPa (10 —1000 atm) were developed early on (6—8) and resulted ia the determination of the reaction equiUbrium constant (9). Experimental data iadicates that is dependent not only on temperature and pressure, but also upon the ratio of hydrogen and nitrogen present. Table 3 fists values for the ammonia equilibrium concentration calculated for a feed usiag a 3 1 hydrogen to nitrogen ratio and either 0 or 10% iaerts (10). 

Table 3. Equilibrium Percent of Ammonia for a Gas Containing a Hydrogen to Nitrogen Ratio of 3 1 at Various Pressures...

Initial carbon-nitrogen ratios (by mass) hetween 35 and 50 are optimum for aerobic composting. At lower ratios ammonia is given off Biological activity is also impeded at lower ratios. At higher ratios nitrogen maybe a limiting nutrient. 

A recent development that has substantially raised our knowledge about the carbon cycle is the measurement of the O2/N2 atmospheric ratio (Heimann, 1997). Figure 11-3 shows the combined curves of CO2 for Mauna Loa and South Pole as well as the recent development of data regarding the oxygen to nitrogen ratio in... 

An important experimental task therefore remains to determine at least around the stoichiometrical composition, the variation of Kp with the composition. At high pressures the maximal yield of ammonia may occur at a hydrogen-nitrogen ratio different from three. 

A number of substituted triazines are used as herbicides, and their biodegradation has been discussed in Chapter 10, Part 1. Treatment of soil contaminated with atrazine (2-chloro-4-(ethylamino)-6-isopropylamino-l,3,5-triazine) illustrated a number of significant features. Although the soil that was used had the potential for degradation, a laboratory experiment with Pseudomonas sp. strain ADP that had an established potential for atrazine degradation revealed important limitations. There was a substantial decline in the numbers of Pseudomonas sp. strain ADP and only limited mineralization. Supplementation with citrate or succinate increased the survival of the strain, and successful mineralization was dependent on the preservation of a carbon/nitrogen ratio >10 (Silva et al. 2004). The last would apply generally to substrates with a low C/N ratio such as triazines. 

Although these studies utilizing Incorporated debris are valuable because they show the potential for allelochemlcals to be released from plant litter, they suffer from a disadvantage. The amount of debris added and Its carbon to nitrogen ratio might lead to alterations In nutrient contents In the soil as the result of proliferation or shifts In populations of micro-organisms. Thus, a control In which a material of similar C/N ratio but lacking allelochemlcals needs to be Included for such studies to be conclusive. The above studies did not Include such controls and thus are not definitive. 

Several researchers emphasized that compost is also an excellent material to use to prevent the acidification and the deterioration of soil productivity [8, 51-54]. Several factors including moisture content, temperature, aeration rate, and carbon to nitrogen ratio have direct influence on composting process, which has been reviewed in detail in the past. 

Polymeric formulations contain a well-proportioned mix of macronutrients, with or without fiber, and are best suited for tube feeding due to lack of sweetening to maintain isotonicity. Standard formulations have a nonprotein calorie-nitrogen ratio of 125 1 to 150 1. 

High-protein formulations have a nonprotein calorie-nitrogen ratio of less than 125 1. Candidates for these formulations require more than 1.5 g of protein/kg/day and are generally critically ill because of trauma, burns, pressure sores, surgical wounds, or high fistula output. 

MCT, medium-chain triglyceride NPC N, nonprotein calorie-to-nitrogen ratio. 

Figure 2. Calcium-nitrogen ratio of the nonepiphyseal parts of the human femur during development. (Reproduced with permission from Ref. 1. Copyright 1965 W. B. Saunders Company.)...

Calculations Involving Nitrogen, Calorie Nitrogen Ratio, and Protein-Calorie Percentage of TPN Solutions... 

Note Do not take into account the calories from protein sources in computing calorie nitrogen ratio. 

A TPN solution contains 0.5 L of 25% dextrose and 0.5 L of 8.5% amino acid solution. What is the non-nitrogen calories to grams of nitrogen ratio (Cal N) for this TPN formula ... 

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