Nitrogen, solid models

For the conversion of the solid reburn fuel complete fuel conversion is assumed. The model for the conversion of the fuel bound nitrogen during pyrolysis into HCN and NHj is based on experimental data of single particle pyrolysis at 800 °c Table 4 . Since the correlation found between the HCN/NHj ratio and the fuel-0/fue -N ratio is valid for various fuels and nitrogen containing model substances, it is also base for the implemented model. 

Results of model calculation of isotherms of adsorption and desorption of nitrogen on model porous solids parameters listed in Table 1 are shown in Pig. 2. The isotherms in Pig. 2 are numerated as the corresponding model porous solids in the upper line of the table. All isotherms were normalized by limiting values of adsorption for P/P = 0.99. The model porous solid 1 and the isotherm 1 are results of averaging of 40 oalculatlons. 

Experimental data on nitrogen obtained from spin-lattice relaxation time (Ti) in [71] also show that tj is monotonically reduced with condensation. Furthermore, when a gas turns into a liquid or when a liquid changes to the solid state, no breaks occur (Fig. 1.17). The change in density within the temperature interval under analysis is also shown in Fig. 1.17 for comparison. It cannot be ruled out that condensation of the medium results in increase in rotational relaxation rate primarily due to decrease in free volume. In the rigid sphere model used in [72] for nitrogen, this phenomenon is taken into account by introducing the factor g(ri) into the angular momentum relaxation rate... 

The interstellar dust was shown to contain quinone derivatives as well as oxygen-rich condensed aromatic compounds the quinones were present in both hydrated and carboxylated form. Very little nitrogen was present in the compounds detected. The cometary material, however, contained condensed nitrogen heterocycles. Hardly any oxygen was detected in the solid phase of the cometary dust it possibly evaporates from the tail of the comet in the form of water or oxidized carbon compounds. The authors assume that these analytical results could lead to a reconsideration of the current biogenesis models (Kissel et al 2004 Brownlee, 2004). 

Fig. 1. Abundance gradient of N/O predicted by models adopting stellar yields where rotation is not taken into account (as model 7 of [3] - thin solid line) and the same models computed with MM02 yields ([2] - thick solid line). A model where we increased only the amount of primary N in massive stars for metallicities below Z=10-B overlaps with the thick solid line shown here [1], This shows that the N/O gradient along the MW disk is affected mainly by the amount of nitrogen production in low and intermediate mass stars and not the primary N in massive stars. For the abundance data see [3] and references therein - asterisks are B stars (see Cunha, this conference).

Larsen T, Luxhoi J, Magid J, Jensen LS, Krogh PH (2007) Properties of anaerobically digested and composted municipal solid waste assessed by linking soil mesofauna dynamics and nitrogen modeling. Biol Fertil Soils 44 59-68... 

Dohrmann also supply an automated nitrogen analyser with video display and data processing (model DN-1000) based on similar principles which is applicable to the determination of down to O.lmg L 1 nitrogen in solid and liquid samples. 

Mono(bromophenoxy)phenol (I). The mono(bromophenoxy)phenols required for the monomeric models were synthesized by two methods. Method A A mixture of pyridine (90mL), diol (60 mmol), dibromobenzene (56.4g, 240 mmol), anhydrous potassium carbonate (33.3g, 250 mmol) and cuprous iodide (1.62g, 9 mmol) was heated at reflux under nitrogen for 20h. After cooling to room temperature, the reaction mixture was acidified with IN HC1 and the product extracted with chloroform. The chloroform was evaporated and the residue extracted with 10% aq. NaOH. The aqueous phase was acidified, extracted with chloroform, and reduced in volume to an oil that was stirred with 20% aq NaOH to afford the sodium salt of the product. The salt was Isolated and dried to give a white solid. The solid was acidified to pH 1 in water, and the freed mono(bromophenoxy)phenol was washed with water and dried. C-H analysis for products was satisfactory. 

Air at room temperature and pressure consists of 99.9% void and 0.1% molecules of nitrogen and oxygen. In such a dilute gas, each individual molecule is free to travel at great speed without interference, except during brief moments when it undertakes a collision with another molecule or with the container walls. The intermolecular attractive and repulsive forces are assumed in the hard sphere model to be zero when two molecules are not in contact, but they rise to infinite repulsion upon contact. This model is applicable when the gas density is low, encountered at low pressure and high temperature. This model predicts that, even at very low temperature and high pressure, the ideal gas does not condense into a liquid and eventually a solid. 

Figure 46 presents the comparison between experimental results (symbols), obtained over a different monolith sample (volume 10cm3) upon performing a TPR run, and the corresponding model predictions (solid lines) 1,020 ppm of NH3 and 960 ppm of NO were fed in a stream of 10% H20, 10% 02, balance nitrogen, with an SV = 36,000 h-1. 

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