N/Ar ratios

Nitrogen abundances in the atmospheres of Earth and Venus are comparable, being much higher than that of Mars. Meteoritic 8 N values overlap the terrestrial-atmosphere and the lower-mantle values, while that of Mars atmosphere is much higher. Planetary N/ Ar ratios fall between meteorite and solar ratios. While much of the terrestrial nitrogen at the surface is in the atmosphere with = o%o (where =... 

Esters and amides may be sulfinylated. Addition of a mixture of t-butyl acetate and sulfinate ester 19 to a THF-ether solution of magnesium diisopropylamide led to the formation of (R)-(+)-f-butyl p-toluenesulfinylacetate (49) in 90% yield (equation 14)7. t-Butyl propanoate and butanoate also underwent this sulfinylation to give 50 and 51 in yields of 68 and 45%, respectively83. The diastereomeric ratio was 1 1 for 50 and 3 7 for 51. These esters may also be obtained by alkylation of 49. Similarly, treatment of a-lithio-A, A -dimethylacetamide with sulfinate ester 19 gave (R)-( + )-N, Ar-dimethyl-p-toluene-sulfinylacetamide (52) (equation 15)84. 

The comparison of coronal and photospheric abundances in cool stars is a very important tool in the interpretation of the physics of the corona. Active stars show a very different pattern to that followed by low activity stars such as the Sun, being the First Ionization Potential (FIP) the main variable used to classify the elements. The overall solar corona shows the so-called FIP effect the elements with low FIP (<10 eV, like Ca, N, Mg, Fe or Si), are enhanced by a factor of 4, while elements with higher FIP (S, C, O, N, Ar, Ne) remain at photospheric levels. The physics that yields to this pattern is still a subject of debate. In the case of the active stars (see [2] for a review), the initial results seemed to point towards an opposite trend, the so called Inverse FIP effect , or the MAD effect (for Metal Abundance Depletion). In this case, the elements with low FIP have a substantial depletion when compared to the solar photosphere, while elements with high FIP have same levels (the ratio of Ne and Fe lines of similar temperature of formation in an X-ray spectrum shows very clearly this effect). However, most of the results reported to date lack from their respective photospheric counterparts, raising doubts on how real is the MAD effect. 

XPS analyses of the deposits made under He showed the presence of V, C, N and O. Upon sputtering the surface with Ar+ ions, the amount of O and C decreased and the V 2p signal was enhanced. However, the N Is signal remained low in all cases. Carbon occurred both as carbide and free carbon. The temperature had no appreciable effect on the N/V ratio (Table... 

Figure 14.8 Vertical profiles of properties at 19°N, 67°E in the Arabian Sea (all data except for N2 collected onTN039 cruise of US JGOFS on 1-2/10/1994). (A) O2 (circles) and NOs (triangles) (B) N2O (circles) and N02 (triangles) (C) NOs deficit according to Codispoti et al. (2001) (dots connected by the solid line), N according to Gruber and Sarmiento (2002) (small filled triangles connected by the dashed line), and excess N2 calculated from the N2/Ar ratio (larger unconnected symbols - crosses for data collected on two different cruises from this site and triangles for those from other stations also located within the denitrification zone).

Figure 14.11 N2/Ar ratio normalized by equilibrium saturation values within (circles) and outside (crosses) the denitrification zone. Note that stations outside the denitrification zone were located within a broad latitudinal band (29°S-8.5°N) (from Devol eta/., 2006b).

Figure 3 Helium and argon isotope compositions of MORE ( Popping Rock from the Atlantic, Shona ridge section, and N. Chile ridge) and selected islands. " °Ar/ Ar ratios vary widely due to variahle amounts of atmospheric...

We are now producing 3,000 tons of N,Ar-diethylgeranylamine 1 annually according to Eq. (2) [6]. In the industrial operation, where drastic conditions such as the higher reaction temperature of 120 °C and the lower catalyst ratio (1 to 100) are required, the regioselectivity drops to 92%. The crude telomer consists of six regioisomers, which were formed by all possible modes of addition between di-ethylamine and the conjugated diene of 4 (Scheme 1) [3]. 

The abundance ratio N/ Ar in lunar samples is about an order of magnitude higher than the corresponding solar wind ratio (e.g., Kerridge 1993). 

Gas discharges from island arc volcanoes and associated hydrothermal systems have N2/ Ar ratios that reach a maximum of 9.7x10", with 5 N values up to +4.6%o (Sano et al. 2001). This would indicate that a significant proportion (up to 70%) of the N2 could be derived from a subducted sedimentary or crustal source. The situation is reversed in the... 

Figure 8. (A) A water column is divided into fifty equal unit cells and it is assumed there is no liquid or dissolved gas between cells. Each cell originally has the noble gas content of air-equilibrated water and all calculated Ne/Ar ratios are normalized to this value to obtain a fractionation factor F. The column temperature is taken to be 325 K, which for pure water gives Knc = 133245 atm and Kaf= 55389 atm. A gas bubble of constant volume is passed sequentially through the column, equilibrium assumed to occur in each water cell and the Ne and Ar partitioned into the respective gas and water phases (Eqn. 16). The evolution of the Ne/Ar ratio in the gas bubble (bold) and each water phase increment (Faint) is shown for different gas/water volume ratios, Vg/Vi. The gas bubble Ne/Ar ratio approaches the maximum fractionation value predicted for a gas/water phase equilibrium where as Vg/Vi -> 0, F Knc/Kat. The cell Vg/Vi ratio only determines the rate at which this hmit is approached. (B) The same water column with a fixed cell Vg/Vi ratio of 0.01. n subsequent bubbles are passed through the column and the He/Ne distribution between phases calculated at each stage. The gas bubble Ne/Ar ratio evolution for n = 1, 10, 20 and 30 is shown in bold, together with the residual Ne/Ar in the water colunm cells (faint lines). All gas bubbles approach the limit imposed by the phase equilibrium model. The water phase is fractioned in the opposite sense and is fractionated in proportion to the magnitude of gas loss following the Rayleigh fractionation law (Eqn. 24).

The influence of ionization on the electrical conductivity is quite obvious the plasma is an electrical conductor when the gas is sufficiently ionized. Ar, Nj and wich have a comparable ionization energy have consequently about the same conductivity (a) as a function of temperature at 10000 K a is 30 Q cm . At the same temperature He has a very low <7 of 5 2 cm" due to its high ionization energy. Figure 12 shows the curves a(T) for He, Ar, Nj and H. The conductivity increases sharply with temperature and reaches a limiting value at 10 cm until second ionization occurs. Finally it must be noted that the electrical conductivities of the mixtures Ar N, Ar—Hj, N —H do not depend on the ratio of the mixture. 

Ar = area required, base plate, in. f = ultimate 28-day strength, psi fu = bearing pressure, psi fi = equivalent bearing pressure, psi Fb = allowable bending stress, psi Ft = allowable tension stress, psi F, = allowable compression stress, psi E, = modulus of elasticity, steel, psi Ec = modulus of elasticity, concrete, psi n = modular ratio, steel-concrete n = equivalent cantilever dimension of base plate, in. Bp = allowable bearing pressure, psi Ki,2,3 = factor... 

Guigon heated T300 fiber at 21°C per min in Ar up to 1100, 1400 and 1700°C with dwell times of lOmin at the temperature and determined the H/C, N/C and N/H ratios (Table 5.13), when molecular N2 was released, but H2 was not released until the temperature was above 1400°C. Toray T800 fiber, with a smaller diameter (about 5 pm instead of 7 pm), showed a lower nitrogen content initially, but maintained a constant N/H ratio of 1, which is consistent with good mechanical properties. 

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