Pumping reactions

The metal lost from the inside of pumps, reaction vessels, pipework, etc. usually contaminates the product. The implications of this depend upon the product. Ppb levels of iron can discolor white plastics, though at this level the effect is purely cosmetic. Ppm levels of iron and other metals affect the taste of beer. Products sold to compositional requirements (such as reagent-grade acids) can be spoiled by metal pick-up. Pharmaceutical products for human use are often white tablets or powders and are easily discolored by slight contamination by corrosion products. 

If the rate of polymerization over this small range of overall conversion can be assumed to be constant, then the average Ap is 1.16 x 10 4 0.10 x 10 4g/cm3 The standard deviation leads to an error in the percentage conversion of 0.02% for the 59% conversion datum. By comparing the estimate for the error in the percentage conversion within the calculated value in Table I shows that the actual pumped reaction mixture leads to an order to magnitude larger error. 

Polvani, C. Blostein, R. (1988). Protons as substitutes for sodium and potassium in the sodium pump reaction. J. Biol. Chem. 263,16757-16763. 

Temperature dependent studies of reaction (1) show that the energy transfer rate constant for the pump reaction (la) is approximately independent of temperature, and does not follow the T dependence suggested by earlier studies. For supersonic devices operating at temperatures near 150 K the pump rate estimated from the T dependence is too high by a factor of two. Recent measurements of rate constants for I hyperfine level... 

N2F4 + HC1(CH4, ch3f, CH2Fa, CHaBr, CaH, C2H8F, C2H5I) / Av Comparison of hydrogen compounds, analysis of pumping reactions Brus, T.in 158)... 

The carbon-monoxide chemical laser exhibits a variety of pumping reactions. Laser action was first reported by Pollack in CS2/02 photolysis 125>. The pumping scheme in this case is believed to be the following 126> ... 

CSg + O2 / hv Analysis of pumping reactions, new lines Gregg, Thomas... 

There is a large number of chemical laser publications that deal with the investigation of the output spectra, mostly in a rather empirical fashion. The two questions which may be answered qualitatively concern the identification of the pumping reaction and the confirmation of predictions for the output composition. Such predictions may be based on spontaneous infrared luminescence measurements. 

Power levels above 1 kW are reported. The efficiency of emission of chemical energy to laser power is 16% at low SFe flow rates and approximately 10% at peak power. Fig. 19 gives a schematic representation of some of the operational features. It is intuitively obvious that, in order to have an efficient laser, it is necessary that the rate of H2 diffusion into the jet and the rate of the pumping reaction be rapid compared with the rates of collisional deactivation. The performance of a corresponding DF laser has also been investigated 78>. The ratio of DF to HF laser power is 0.7 under similar flow conditions. The observed output spectra are reproduced in Table 13. It has been suggested that the lower DF efficiency is due to vibrational deactivation by N2. The efficiency and intracavity power of HF and DF is indeed the same with He as a diluent instead of N2. The efficiency of HF lasers with He and, with N2 carrier gases is compared in Fig. 20. 

It is somewhat difficult to compare these predictions with experimental results since no really systematic experimental study has yet been published. This is due in part to difficulties in preparing mixtures of H2 and Fa of any desired composition and pressure and also to experimental limitations in the sufficiently rapid initiation of the pumping reaction. However, as far as the experimental information goes, it can be concluded that the efficiency is considerably lower than expected. For instance, in flash photolysis-initiated HF lasers a chemical efficiency of below 1% is usually found 101>. Two suggestions may be made to explain this discrepancy. One may look at it as either a chemical rate problem or a laser problem. In the first case, some unknown rate process must be assumed to reduce the build-up of excited HF. Since the formation and deactivation rates are known with some accuracy, this could only be excessive recombination or an unusually high rate of the reverse reaction 102>. Alternatively, parasitic oscillations or superradiance have been claimed to cause radiation losses in off-axis... 

A simple approach is to obtain overall rate constants for the pumping reactions from the pulse shape of the emission signal. 

The reactants ( fuel ) consumed by the pumping reaction are equivalent to a hot reservoir supplying energy E, and entropy to the system at rates... 

Figure 5.15 Swenson atmospheric up-pumping reaction-type DTB crystallizer.

Detection tubes, such as civil defense kit, contain special reagents impregnated on inert supports. Air is sucked through the tube with a special pump. Reaction between the reagents in the tube and CWA takes place, and different colors are produced based on the CWA. 

Ogura H, Shimojyo R, Kage H, Matsuno Y, Mujumdar AS. Simulation of hydration/ dehydration of CaO/Ca(OH)2 chemical heat pump reaction for cold/hot heat generation. Drying Technology 17(7 8) 1579-1592, 1999. 

The absence of a complete population Inversion in the flash-initiated CFBr3 - SO2 system accounts for the weak CO laser intensity, compared with that detected in the CHBr3 - SO flash (18). In the CHBr3 - SOj system, the primary pumping reaction was assumed to be 0 + CH, which probably proceeds through the HCO complex with a shallower depth of about 20 kcal/ mole. The dynamics of this highly exothermic reaction (Ah° =... 

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