Temperature delayed--------coefficient

If both the prompt and delayed temperature coefficients are negative, then Cl, C2, and C3 are all positive, as is also 73. We consider first the condition for sustained oscillations. In this case si = 0, and we must have... 

The delay, t0, preceding the onset of the main reaction may include contributions from (i) the time required for the sample to attain reaction temperature, h, (ii) additions to fh resulting from changes within the reaction sample, e.g. water removal (endothermic) from a hydrate, td, phase transitions, etc. and (iii) slow processes preceeding establishment of the main reaction, which are to be regarded as the true induction period, The effective values of th, td and may show different temperature coefficients so that the magnitude of t0(=th + ta + i) may vary with temperature in a complex manner, perhaps differently from that of the subsequent rate process. 

Fig. 22 B. Exeitation spectrum at room temperature showing the intensity of delayed fluorescence of a naphthalene crystal as a function of the wavelength of the exciting light. The ordinate is proportional to the square of the singlet-triplet absorption coefficient. (From Avakian and Abramson, Ref.52))...

See also Delay to Ignition and Its Temperature Coefficient in Vol 3 of Encycl, pp D53-D54 and Notes 1 2, which are given after the Refs... 

Effect of Varying Both the Zinc Stearate and Barium Chromate Content on the Burning Rate and Temperature Coefficient of a Tungsten Delay Composition... 

Here A//adS is the enthalpy of adsorption, T is the temperature, and AAads is the entropy change associated with the adsorption of the protein onto the surface. Protein adsorption will take place if AGads < 0. Considering a complex system, where proteins are dissolved in an aqueous environment, and are brought into contact with an artificial interface, there are a vast number of parameters that impact AGads due to their small size (i.e., large diffusion coefficient), water molecules are the first to reach the surface when a solid substrate is placed in an aqueous biological environment. Hence, a hydrate layer is formed. With some delay, proteins diffuse to the interface and competition for a suitable spot for adsorption starts. This competition... 

In the vicinity of 90° K the temperature coefficient of the amount adsorbed can be estimated from the published isotherms (8). This coefficient is, of course, dependent upon the pressure and the apparatus dimensions. In the pressure range where the delay occurred, and on the basis of the dimensions of the apparatus, the temperature coefficient of the amount adsorbed was calculated to be about 2% per °K. The temperature coefficient of residual pressure was of the order of 20% per °K. The greater temperature sensitivity of the residual pressure suggests that this measurement might account for the delay, but the observed pressure changes associated with delay are relatively very large. 

A few results using different sample sizes indicated that the temperature coefficient did not vary greatly with coverage in the range examined, in spite of the effect of sample size on peak delay at a given temperature. 

In fact this reaction has been suggested by Benson and Buss as a replacement for reaction (31). If reaction (48) is in equilibrium and reaction (49) replaces reaction (31), then the rate coefficient attributed to reaction (31) is really 49 48,-48- Nicholas and Norrish have re-examined the flash photolysis of CI2-O2 mixtures at room temperature and monitored the products at short delay times before [CIO] became large. Their results support reaction (49) and they report it-48/ 49 15 or 7.7, depending on the extinction coefficient of CIO. They also found = (6.2+1.l)x 10 l. mole . sec with N2 as a chaperone. 

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