Temperature coefficient of delay

The fundamental parameters controlling operating characteristics of SAW-based sensors are the SAW velocity, the temperature coefficients of delay (TCD), the electromechanical coupling factor, and the propagation loss. In SAW applications, the coupling factor relates to the maximum bandwidth obtainable and the amount of signal loss between input and output that determines the fractional... 

The temperature dependencies of the permittivity of the nanocomposite materials based on low-density polyethylene with iron nanoparticles obtained in our experiments can be used for determining the optimum geometric parameters of acoustic waveguides, the type and operating frequencies of waves in structures of the piezoelectric plate nanocomposite layer, in which the temperature coefficient of delay for acoustic waves can be significantly decreased while the electromechanical coupling coefficient has a fairly high level [10]. 

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

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. 

Moderator (and coolant) temperature coefficient of reactivity Moderator void coefficient of reactivity Fuel temperature coefficient of reactivity Effective prompt neutron lifetime Delayed neutron fraction(s)... 

Inherent safety and ease of control. Any liquid fuel which expands on heating gives an immediate negative temperature coefficient of reactivity. This effect is not delayed by any heat-transfer process. The rate of expansion is limited only by the speed of sound (shockwave) in the liquid. This instantaneous effect tends to make the reactor self-regulating. Adjustment of fuel concentration can be used as an operating control. 

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... 

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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