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It does not, however, give a measure of true protein content, as it measures nonprotein nitrogen in addition to the nitrogen in proteins. This is evidenced by the 2007 pet food incident and the 2008 Chinese milk powder scandal, when melamine, a nitrogen-rich chemical, was added to raw materials to fake high protein contents. Also, different ...
The measured signal from the thermal conductivity detector for the unknown sample can then be converted into a nitrogen content. As with the Kjeldahl method , conversion of the concentration of nitrogen in a sample to the crude protein content is performed using conversion factors which depend on the particular amino acid sequence of the ...
Nitrogen-15 (15 N) tracing is a technique to study the nitrogen cycle using the heavier, stable nitrogen isotope 15 N. Despite the different weights, 15 N is involved in the same chemical reactions as the more abundant 14 N and is therefore used to trace and quantify conversions of one nitrogen compound to another.
Nitrogen is a chemical element; it has symbol N and atomic number 7. Nitrogen is a nonmetal and the lightest member of group 15 of the periodic table, often called the pnictogens. It is a common element in the universe, estimated at seventh in total abundance in the Milky Way and the Solar System.
Liquid nitrogen is a compact and readily transported source of dry nitrogen gas, as it does not require pressurization. Further, its ability to maintain temperatures far below the freezing point of water, specific heat of 1040 J ⋅kg −1 ⋅K −1 and heat of vaporization of 200 kJ⋅kg −1 makes it extremely useful in a wide range of ...
Frequently used in mixtures with e.g. nitrogen or air. Nitrogen: N 2: 1.15: 28: 1.251 – – not Often used at high pressure. Does not facilitate combustion. Can be used with 10–20% of SF 6 as a lower-cost alternative to SF 6. Can be used standalone or in combination with CO 2. Non-electron attaching, efficient in slowing electrons. Air: 29 ...
Ab-initio-MO calculations have shown that, in addition to the σ binding of the free electron pair of nitrogen to the metal, there is a π binding from the d orbitals of the metal to the π* orbitals of nitrogen, which strengthens the iron-nitrogen bond. The nitrogen in the α state is more strongly bound with 31 kJmol −1.
When the bed reaches the limit of its capacity to adsorb nitrogen, it can be regenerated by decreasing the pressure, thus releasing the adsorbed nitrogen. It is then ready for another cycle of producing oxygen-enriched air. Using two adsorbent vessels allows for near-continuous production of the target gas.