Oxygen, determination

M. A. IT insky and G. Knorre proposed l-nitroso-2-naphthol as a reagent for cobalt and Zh.I. lotsich - magnesium diiodine acetylene as a reagent for carbonyl group. F.M. Flavitsky developed a method for qualitative analysis based on solid substances as well as a portable laboratory for qualitative analysis. G.V. Khlopin proposed a method for determining oxygen dissolved in water. 

M. De Crescenzi. Phys. Rev. Letts. 30,1949,1987. Use of surface electron energy-loss fine structure (SEELFS) to determine oxygen-nickel bond length changes for oxygen absorbed on Ni (100) on a function of coverage from 0 to 1.0 monolayer. 

Assessing fire or explosion risks from atmospheres eontaining flammable gas, vapour or dust. Determining oxygen eontent of the working atmosphere. 

The low background pressure (10 mbar) together with the purity of the gases used ensures a low concentration of contaminants. Amorphous silicon films made in the intrinsic reactor have been analyzed by using ERD, which is available in our laboratory [114]. The determined oxygen content in these films typically is lower than 3 x lO cm - which is somewhat lower than the values required for obtaining device quality films reported by Morimoto et al. [167]. 

It is important to note that oxygen bound to hemoglobin has no effect on the P02 of the blood. The amount of oxygen bound to hemoglobin determines oxygen content of the blood. The POz of the blood is determined by the amount of oxygen dissolved in the plasma. 

We have determined oxygen abundances in two large samples, a set of planet-harbouring stars and a volume-limited comparison sample of stars with no known planets, using 3 different indicators [OI] at 6300 A, the OI 7771-5 A triplet, and a set of 5 near-UV OH lines (see [7]). Non-LTE corrections were calculated and applied to the LTE abundance results for the triplet. 

Arterial blood gases are measured to determine oxygenation and acid-base status (Fig. 74-1). Low pH values (less than 7.35) indicate acidemia, whereas high values (greater than 7.45) indicate alkalemia. The PaC02 value helps to determine if there is a primary respiratory abnormality, whereas the I IC( )3 concentration helps to determine if there is a primary metabolic abnormality. Steps in acid-base interpretation are described in Table 74-2. 

Table 2.6 Experimentally determined oxygen isotope fractionation factors relative to water for the aqueous system CO2 — H2O between 5 and 40°C according to 10 hia = A(10 /T ) + B (Beck et al, 2005)...

Factors determining oxygen demand. The heart muscle cell consumes the most energy to generate contractile force. O2 demand rises with an increase in (1) heart rate, (2) contraction velocity, (3) systolic wall tension ( afterload ). The latter depends on ventricular volume and the systolic pressure needed to empty the ventricle. As peripheral resistance increases, aortic pressure rises, hence the resistance against which ventricular blood is ejected. O2 demand is lowered by 3-blockers and Ca-antago-nists, as well as by nitrates (p. 308). 

BASIC PROTOCOL 1 POLAROGRAPHIC MEASUREMENT OF OXYGEN UPTAKE Oxygen electrode equipment is used to determine oxygen uptake as a function of time. After preparing the enzyme (see Support Protocol) and calibrating the instrument, substrate and enzyme are added sequentially to a buffered solution, and the rate of oxygen uptake is monitored by a recorder. 

C. All copolymerizations were carried out without solvent. Below 80 °C azobisisobutyronitrile was used as initiator. At 100 °C the reactions were initiated thermally. At temperatures of 50°, 60°, and 80 °C the reactions were carried out in dilatometers. At 20°C small flasks were used, and the reactions were conducted in a temperature-controlled room over a period of days. At 100 °C sealed glass tubes were preferred. The reactions were stopped at yields below 5%. The composition of the copolymers was determined by oxygen analysis in the analytical laboratories of BASF. The method for determining oxygen was developed in the Untersuchungslaboratorium of BASF (18). 

The use of gas chromatography to determine oxygen in coal is considerably faster than the methods just described. The oxygen produced from coal pyrolysis in a vacuum was converted to carbon monoxide catalytically, and the total quantity of gas was measured. Gas chromatography was then used to measure the concentration of carbon monoxide in the gas. 

All of the reactions just described closely parallel the reactions of the same substrates with organic peracids. They probably involve rate-determining oxygen transfer from a metal-hydroperoxide complex to the substrate via a cyclic transition state, described earlier for the epoxidation of olefins with these reagents433,435... 

Another method, devised by Cohen et al. to determine oxygen-rate gas collision parameters is to define an effective spin-orbit operator that includes r dependence, Zeff/r3, where the value of Zeff is adjusted to match experimental data (76). Langhoff has compared this technique with all-electron calculations using the full microscopic spin-orbit Hamiltonian for the rare-gas-oxide potential curves and found very good agreement (77). This operator has also been employed in REP calculations on Si (73), UF6 (78), U02+ and Th02 (79), and UF5 (80). The REPs employed in these calculations are based on Cowen-Griffin atomic orbitals, which include the relativistic mass-velocity and Darwin effects but do not include spin-orbit effects. Wadt (73), has made comparisons with calculations on Si by Stevens and Krauss (81), who employed the ab initio REP-based spin-orbit operator of Ermler et al. (35). 

The evidence for the proposed mechanism comes from kinetic, spectroscopic (multinuclear NMR), X-ray structure, and theoretical calculations. The kinetic rate law under optimum catalytic conditions is very complex. Under pseudo-first-order conditions, where the concentrations of both 9.35 and the hydroperoxide are much greater than that of allyl alcohol, the rate expression 9.5 is obeyed. In this expression the inhibitor alcohol is an inert alcohol such as isopropanol or f-butanol that is deliberately added to slow down the reaction for convenient rate measurements. The inert alcohol acts as an inhibitor, since it competes with both hydroperoxide and allyl alcohol for coordination to the Ti center. Note that expression 9.5 is consistent with the formation of an intermediate like 9.36, before the rate-determining oxygen atom transfer step. 

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