R ratio

The hydrolysis and polycondensation reactions initiate at numerous sites within the TMOS/H2O solution as mixing occurs. When sufficient intercoimected Si—O—Si bonds are formed in a region, the material responds cooperatively as colloidal (submicrometer) particles or a sol. The size of the sol particles and the cross-linking within the particles, ie, the density, depends on the pH and R ratio, where R = [H2 0]/[Si(0R)4]. 

R = ratio (number teeth in gear divided by number teeth in pinion) The allowable K faetor is given by Allowable K = Material index number/Serviee faetor... 

Crack extension is often observed to vary significantly at the same nominal value of AK (= Y AOpos Tta) for different values of R-ratio. Elber [26] was the first to explain this observation for metals in terms of the crack closure phenomenon. He determined, by measuring specimen compliance, that fatigue cracks open and close at the crack tip at positive values of stress due to contact between crack surfaces behind the crack tip. For elastic fatigue conditions it is generally found that P p = P, and Kop = K, where P is the applied load. 

V = viscosity force G = gravity C = interfacial tension R = ratio m = model p = prototype... 

These MTD (or LMTD) correction factors are read from the appropriate chart, which descrihes the exchanger mechanical and temperature terminal operational conditions. The P and R ratios must he calculated as represented in the diagrams otherwise the factor read will have no meaning. A true counterflow or parallel flow exchanger does not require any correction to the LMTD. 

R = Ratio of the heat capacities of tube-side to shell-side fluid, dimensionless... 

Tj = discharge temperature from cylinder, Rankine R = ratio of cylinder compression... 

R = ratio of compression of compressor cylinder rpm = revolutions per minute... 

R = ratio OD/ID of the tubing r = tubing and casing radial clearance in in. 

In common with many of the alloy-environment systems described so far, if the alloy is not susceptible to stress-corrosion cracking under constant stress or stress intensity, then little or no effect of environment on fatigue crack growth is observed. In these cases, frequency, R ratio and potential within the passive or cathodically protected ranges for titanium have no effect on growth rates. 

Starting Material R Ratio i wtm Product Ratio (smlanti)... 

R = ratio of the maximum deflagration pressure to the maximum initial pressure, as described in NFPA Code-69, Par 5-3.3.1... 

The R2+/R+ ratios for the other rare gases and ethylene were examined, but less extensively. The results were similar to those for argon (Figure 6). We shall mention such data when needed in further discussion. 

Manufacturing economics require that many devices be fabricated simultaneously in large reactors. Uniformity of treatment from point to point is extremely important, and the possibility of concentration gradients in the gas phase must be considered. For some reactor designs, standard models such as axial dispersion may be suitable for describing mixing in the gas phase. More typically, many vapor deposition reactors have such low L/R ratios that two-dimensional dispersion must be considered. A pseudo-steady model is... 

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