Oxygen vs. time

Figure 1. Dissolved oxygen vs time data. The experiments were basalt + synthetic Grande Ronde groundwater (B+SW) and synthetic Grande Ronde groundwater (SW) at 300 bars. Determination of uncertainties for B+SW data points is discussed in Table IV. Uncertainties for SW data were derived from replicable tests.

Figure 17. Core-level spectra of a high-density polyethylene sample after exposure to a stream of oxygen rich in singlet molecular oxygen vs. time of x-ray irradiation...

Figure 7. Measured ppm s oxygen vs Time for LEP Bottles (8.5 mil PP/1.3 Eval - F /45 PC volume-150 cm3, area-155 cm2 Storage 20°C, 65% RH).

In Fig. 1 we display the log(N/0) vs. time and log(N/0) vs. log(0/H)+12 behaviours predicted by two successful models for NGC 1569 and NGC 1705. These models well reproduce several observational constraints - the present-day gaseous and total masses as well as the overall metallicity and oxygen content of the gas - by adopting the same prescriptions on the stellar nucleosynthesis, stellar IMF and galactic outflow onset conditions and efficiency. However, as can be seen from Fig. 1, the present-day N/O ratio is reproduced only for NGC 1569, whilst for NGC 1705 the theoretical N/O ratio during the last 4 Gyr of galaxy s evolution is 0.3-0.4 dex higher than observed at the present time. 

Figure 14. Fourier transform of (A) the oxygen isotope ratio vs. time in C. japonica and (B) deuterium isotope ratio vs. time in C. japonica, transformed into power vs. reciprocal period (average slope subtracted) (26).

Figure 16. Oxygen isotope ratio vs. time in S. gigantea, measured for each year.

Figure 17. Fourier transform, power vs. period, of oxygen isotope ratios vs. time,...

Figure 3. COs pressure vs. time during heating a polycrystalline Rh sample covered with CO and O. These species were deposited at 360 K in varying amounts by predosing oxygen (15.9 L) and then titrating with CO(g) at 7 X 10 3 torr. The heating was then done in vacuo. Titration times are marked in minutes. The small high temperature peak is due to CO interactions with the walls (14).

Figure 11. C02 signal vs. time for the titration of oxygen chemisorbed on Ag...

Fig. 16. Slow isotopic exchange at 35.0°C on Re(V) center, (a) Oxygen-17 spectra showing signal growth vs time for [Re02(CN)4]3. (b) Least-squares fit of the data to the modified exponential McKay equation (7). The total complex concentration [Re] = 0.2 m, pH = 6.6, and fi = 1.2 m (KN03). (Adapted with permission from Roodt, A. Leipoldt, J. G. Helm, L. Abou-Hamdan, A. Merbach, A. E. Inorg. Chem. 1995, 34, 560-568. Copyright 1995 American Chemical Society.)...

Figure 12. Modeling and measurement of oxygen surface diffusion on Pt. (a) Model I adsorbed oxygen remains in equilibrium with the gas along the gas-exposed Pt surface but must diffuse along the Pt/YSZ interface to reach an active site for reduction. Model II adsorbed oxygen is reduced at the TPB but must diffuse there from the gas-exposed Pt surface, which becomes depleted of oxygen near the TPB due to a finite rate of adsorption, (b) Cotrell plot of current at a porous Pt electrode at 600 °C and = 10 atm vs time. The linear dependence of current with at short times implies semi-infinite diffusion, which is shown by the authors to be consistent only with Model II. (Reprinted with permission from ref 63. Copyright 1990 Electrochemical Society, Inc.)...

The relations of molar extinction coefficients and oxygen absorption rates, plotted vs. time, are illustrated in Figures 3 and 4 (solvents, benzene and butyric acid, respectively). The variation of coefficients was parallel to the rate of oxygen absorption—i.e. the larger the coefficient, the higher the oxygen absorption rate. It is considered therefore that the catalyst at its maximum absorption coefficient is in a desirable form for oxidizing acrolein. 

In all cases, the oxidation rate was smallest for experiments involving thiophenol and ferf-butanethiol. The oxygen uptake vs. time curves for cobalt-catalyzed reactions showed an initial high slope followed by a decrease in slope after ca. 30% reaction to a final steady value. 

Li et al. [107] also reported the change in residual radical concentration vs oxygen permeation time for a homopolymerization of EGDMA. At 110°C, the radical concentration decreased by approximately 12.5% in 90 min. While at 180 °C, the radical concentration dropped nearly 62.5% over the same time period. While these reactions occurred over a relatively short time period, the temperatures were quite high and certainly one would expect significantly reduced rates at lower temperatures below the glass transition temperature of... 

Transient kinetic experiments were performed also in the presence of a higher concentration of oxygen, namely 6% v/v. Results collected at different temperatures are displayed in Fig. 37B (symbols) in terms of NH3, NO and N2 outlet concentration traces vs. time ( = 200, 225, 250, 275°C). They are qualitatively similar to those with 2% v/v oxygen feed in Fig. 37A and discussed above. Particularly, two different behaviors of the NO and the N2 concentration traces were again observed when the NH3 feed was opened up/shut down. In the high-T range, monotonic temporal evolutions were observed e.g. at NH3... 

Co-Oxidation in absence of Added Catalysts or Inhibitors. Figure 1 (curves A,A, B,B ) shows typical oxygen uptake vs. time curves obtained after using the procedures for purifying indene, thiophenol, and benzene and cleaning the reaction vessel as described above. On the experience of several hundred runs, the reproducibility expected was such that the time for uptake of 0.5 mole of 02 per mole of PhSH would be in the range 150 to 200 minutes. Despite all efforts, it was estimated that iron... 

Further experiments were therefore carried out with oxygen in the gas phase in order to maintain a high concentration of lattice oxygen in the solid phase. In fig.2 conversion vs time plots are shown for experiments in which the molar ratio 02/l was lower than 0.5. After each experiment (2a and 2b) the catalyst (l.Og of H-Cu-0203T) was reactivated in an Oz-He gas stream which restores its initial activity. 

Fig. 21. Time-course for phosphate-oxygen exchange catalyzed by glutamine synthetase. The fractional concentrations of the species P[lsO]4 ( ), P[ia0]3[l60]1 (O), P[180]2[,60]2 ( ), P[180]i[I60]3 ( ), and P[160]4 (A) are plotted vs. time for the scheme given in Balakrish-nan et al. (90). Reprinted with permission of Academic Press.

Fig. 2.10 Amounts of 02 consumed as a result of photocatalytic reactions in ethanol-containing aqueous solution, with and without 0.1 M phenol present, under UV irradiation for 1 min. The amount of 02 consumed was estimated using a finite difference method from the oxygen concentration vs. time curves (light intensity, 2.5 mW/cm2 microelectrode potential, -1 V vs. SCE).

The exciton migration within aggregates of cyanine dyes and the possibility of oxygen diffusion into the porous dye film result in a bulk generation of photocurrent [80]. Photoholes produced due to the oxidation of excitons by molecular oxygen diffuse to the back contact. The diffusion coefficient of charge carriers in dye layer (Dc) can be evaluated from the potential-step chronoamperometric measurements in the indifferent electrolyte. Considering dye film as a thin-layer cell, the current vs. time dependence can be described as follows [81] ... 

For typical oxygen pressures, the transition from passive to active oxidation occurs at around 600-750 °C surface temperature. Curves for oxygen uptake vs. time display a transition from a simple Langmuir-Hinshelwood (LH) form for passive oxidation, to a more slowly increasing but sigmoidal form (reflecting autocatalytic aspects to the oxide island formation process) for active oxidation. 

Figure L Uptake of oxygen by selected coals vs. time no heat or pumping (%) heated at 65° C under vacuum ( ).

Figure 1. Plots of oxygen uptake vs. time after Kelleher...

Fig, 3. 58 Effect of amount of active oxygen vs. amount of igniter that results in the maximum rale of pressure increase at deflagration of organic peroxides in the improved time/pressure test... 

Figure 8. PBS thickness removed vs time in fluorocarbon plasma post 3 minute oxygen plasma exposure.

Fig. 5. Concentration of sulfur dioxide in an oxygen plasma measured by mass spectrometry vs. time during PBTMSS etching under various conditions. RIE (20 mTorr Oj 10 seem) A -320 V, B -350 V, C -380 V, D -450 V, E -550 V SME (20 mTorr, 10 seem Oj) F 50 W, G 100 W...

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