Full rise time

For each formulation evaluated, free rise cup foams (see Section 1.2.2.1) were poured to determine reactivities and foam shrinkage. Data recorded were gel time, full rise time and final height. The free rise cup foams were tested for final heights and free rise density after 24 hours. Height measurements were carried out using a Mitutoyo height gauge. All experimental formulations reported in this work were matched by rise profile to each control formulation. 

Take i0 = 10-6 A cm-2 at 25°C. Explore the appropriate time and potential range to form a galvanostatic transient relation with the parameters stated. (Note The so-called "rise time of the potential is about 4C R, where R = dV/ddt. Calculate the full V—t curve to 99% of the steady state. (Bockris)... 

Measurements were made with a cathode-ray beam switched on and off with a flat-topped pulse having 20 nsec rise and fall times. For the europium-doped sample, the rise time to 90 per cent of full intensity was 10 4 sec the decay to 10 per cent luminescence was also 10 4 sec. 

Time Constant. The time constant t is a measure of the speed of response of a detector. Specifically, it is the time (usually in seconds or milliseconds) a detector takes to respond to 63.2% of a sudden change of signal, as shown in Figure 7.4. The full response (actually 98%) takes four time constants and is referred to as the response time. Unfortunately, some workers define response time as 2.2 time constants (not 4.0), corresponding to 90% of full scale deflection (not 98%) others define a rise time as the time for the signal to rise from 10 to 90%. To further confuse the situation, some use the terms time constant and response time interchangeably. This lack of consistency can be found in the ASTM specifications. 

The rise time for airless-sprayed urethane foam is about 30 s. It can be refoamed for additional thickness after this period. The foam can be walked on after 3 to 4 minutes and reaches its full properties in 24 h. The airless spray gun is held about 30 in. (76 cm) from the surface and moved steadily over it. Dispensing rates of 4 to 6 lb (1.8 to 3.6 kg) per minute are generally considered optimum for most spray applications. The surface on which the foam is sprayed must be free of loose scale or grease. The adhesion of urethane foam to steel is essentially equal to the tensile strength of the foam, provided the surface is clean. Aluminum surfaces, on the other hand, do not provide a good bond unless a primer coat, such as vinyl wash, is used prior to spray foaming. 

The rise time for airless sprayed urethane foam is about 30 seconds. It can be refoamed for additional thickness after this period. The foam can be walked on after 3-4 minutes and reaches its full properties in 24 hours. The airless spray gun is held about 30 inches (76 centimeters) from the surface and moved steadily over it (12). Dispens-... 

As a consequence of these difficulties, a full kinetic analysis of the fluorescence decay times and their amplitudes was mostly not carried out, except for Py on Si-C. g in contact with methanol/water (21), see Section 4.2.3. Instead, the excimer rise time has been used to obtain information on the surface dynamics of Py on silica (Section 4.5). As has been shown in Section 2.2.3, even this procedure has to be handled with caution. 

In Figure 9, the rate of evolution of carbon dioxide from formulation "A" is compared with the rise and "gel profiles" for this formulation. A maximum in cell-opening is measured before full rise height is achieved and at the time of an inflexion in the rise-rate curve. This maximum in the rate of cell-opening happens while the processes measured by "gel profile" are occurring. 

Unfortunately, some workers define response time as 2.2 time constants (not 4.0) that corresponds to 90% (not 98%) of full scale deflection others define a rise time as the time required for a signal to rise from 10% to 90%. This lack of consistency can even be found in some ASTM specifications. 

FIGURE 30 Temporal variation of (a) intensity, (b) phase, and (c) frequency produced by a medium with a positive nonlinear refractive index, (d) Spectrum of a self-phase-modulated pulse. The asymmetry results from a rise time that was 1.4 times faster than the full time. [Part (d) reproduced from Reintjes, J. (1984). Nonlinear Optical Parametric Processes in Liquids and Gases, Academic Press, Orlando, FL.]... 

Cabling, which might be thought as the least likely component of a system to cause problems, is a potential source of serious signal distortion and attenuation. The behaviour of a pulse in a cable may vary depending upon the shape of the pulse, and in particular on its rise time. (Rise time is defined as the time it takes a pulse to rise from 10 % of its full height to 90 % see Figure 4.7 below.) A pulse whose rise time is short compared to the time the... 

It has been said that, in the fullness of time, all lead used by human populations eventually becomes lead dispersed and lead contamination in the form of future background with the rise and fall of cultures and civilizations (NAS/NRC, 1993, p. 18). There are nmnerous examples of this inexorable movement of lead from use to waste stream, a movement aided by complex entries and exits from numerous and diverse environmental compartments. Examples include lead that becomes the material of discrete artifacts as well as lead that is dispersed uniformly with its production into environmental compartments as constituents of the atmosphere, leaded dusts from atmospheric fallout, lead in riverine and marine sediments, lead in biota, etc. The close relationship of lead production to eventual lead dispersal and environmental contamination over both the near and long term means that one cannot get a handle on the latter without some quantitative assessment of the former. 

The reaction to form polyurethane foams goes through a number of clearly defined and measurable stages. These stages are Cream time, I/2 Cup time, Full Cup time. String time. Tack Free time and End of Rise time. The effect of various loadings of PFA upon the reactivity of the polyurethane system was measured. These were compared to the reaction times for the standard polyurethane system. The results are given in table 3 and table 4 for undried PFA and dried PFA respectively. 

The original pressure should not be more than 2,000 lb. per sq. in. if the maximum working pressure for the autoclave is 5,000 lb. The full operating pressure is not applied at the beginning because the pressure will rise as the bomb is heated thus at 256°, the pressure will be 1 - 8 times that at 20°. 

The speed control operates the governing valve to maintain steam flow commensurate with load demand while holding speed essentially constant. For sudden load changes there will be a short-time overshoot, and a special case is the instantaneous loss of load, load dump at full load. The usual specification states that the overshoot on load dump must not exceed 9 to 10 percent of rated speed. The settled speed rise will of course be equal to the regulation, 4 or 6 percent for a NEMA Class C or B governor and less than I percent for Class D. 

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