Set delayed

In this technique a whole absorption spectrum is obtained for one set delay time between the pump and probe pulses. The delay time can be varied to obtain spectra at different times. 

A long-lived transient was observed following the excitation of C2H2 using a 3000 J 5 ps flash in Nj. A 2 ps spectroscopic flash, triggered by a set delay after excitation, monitored the transient absorption in the wavelength region 140— 157 nm. The reactions of OH and OD with butane, [ H io]-butane, and pentane, ... 

This is a simple and yet very powerful use of Mathematica s set-delay utility =. The right-hand side is the whole recursive equation with an equal sign, but by placing this after the set-delay = it becomes a pattern that will not be evaluated until n is specified. When n is specified, then it begins with the seed and evaluates the function until it gets to the value of n. Thus, when we set n = 4, we obtain the concentration expression for the exit of the fourth CSTR. If we place the function in a Table, and set n = 4 we obtain the exit concentrations for all four of the CSTRs. We follow the same procedure for cb[n] as shown here ... 

Within the Do loop we have the same recursion that we had implemented by rules—we specify the seed as call] and then the recursion relation as ca[m]. The set-delayed function argument of cal[n ] supplies n, as the limit of the iterative sequence. The last statement just outside the Do loop writes the value of ca[n] and then it stops. We implement the same approach for species B ... 

Figures 4.8l °l and 4.91 show the setting behavior of the latex-modified mortars and concretes respectively. The setting is delayed with an increase in the polymer-cement ratio. The slower setting does not cause inconvenience in practical applications. NR-modified mortar causes the most delay in setting. Usually, the reasons for the setting delay are that the surfactants such as alkylbenzene sulfonates and caseinates contained in latexes inhibit the hydration of cement.I J Rheological studies on PVAC-modified concrete by Zivical l revealed that the hydration of cement is inhibited by the adsorption of the surfactants on the binder surface.

When a free induction decay is Fourier transformed, some of the peaks may appear distorted or even inverted. They are then said to be out-of-phase with respect to a reference peak. Examples of the quartet of ethylbenzene before and after phase adjustment are given in Figure 3.14. The phase errors may be due to the phase detector setting, delay between pulse and start of data acquisition, or filter settings. The phase is digitally corrected after Fourier transformation. 

The chemistry of cement slurries is complex. Additives will be used to ensure the slurry remains pumpable long enough at the prevailing downhole pressures and temperatures but sets (hardens) quickly enough to avoid unnecessary delays in the drilling of the next hole section. The cement also has to attain sufficient compressive strength to withstand the forces exerted by the formation over time. A spacer fluid is often pumped ahead of the slurry to clean the borehole of mudcake and thereby achieve a better cement bond between formation and cement. 

Fig. 3 Measurement of signal stored in the memory buffer. Two markers can be set to arbitrary selected delay positions along the buflfer length and signal values can be read and compared.

Figure 1. shows the measured phase differenee derived using equation (6). A close match between the three sets of data points can be seen. Small jumps in the phase delay at 5tt, 3tt and most noticeably at tt are the result of the mathematical analysis used. As the cell is rotated such that tlie optical axis of the crystal structure runs parallel to the angle of polarisation, the cell acts as a phase-only modulator, and the voltage induced refractive index change no longer provides rotation of polarisation. This is desirable as ultimately the device is to be introduced to an interferometer, and any differing polarisations induced in the beams of such a device results in lower intensity modulation. 

The required acoustic verifications depend on what the probe is made for. If the probe is used as an angular scamiing system with a fix set of elements, then we think it is only needed to characterize the array behavior with a few selected time delay laws to isolate the angular steering capability and the foeusing capability as explained before. 

At still shorter time scales other techniques can be used to detenuiue excited-state lifetimes, but perhaps not as precisely. Streak cameras can be used to measure faster changes in light intensity. Probably the most iisellil teclmiques are pump-probe methods where one intense laser pulse is used to excite a sample and a weaker pulse, delayed by a known amount of time, is used to probe changes in absorption or other properties caused by the excitation. At short time scales the delay is readily adjusted by varying the path length travelled by the beams, letting the speed of light set the delay. 

Figure C3.6.1 (a) WR single-handed chaotic attractor for k 2 = 0.072. This attractor is projected onto tire (c, C2) plane. The maximum value reached by c (t) is 54.1 and tire minimum reached by <7 " 2.5. The vertical line, at Cj = 8.5 for < 1, shows the position of tire Poincare section of tire attractor used later, (b) A projection, onto tire cft- ),cft2)) plane, of tire chaotic attractor reconstmcted from tire set of delayed coordinates cft),cft ),c (t2), where t = t + and t2 = t -I- T2, for 0 < t < 00, and fixed delays = 137 and T2 = 200. Note tliat botli cft ) and cftf) reach a maximum of P and a minimum of <"T""so tliat tire tliree-dimensional reconstmcted attractor is...

The elongation of a stretched fiber is best described as a combination of instantaneous extension and a time-dependent extension or creep. This viscoelastic behavior is common to many textile fibers, including acetate. Conversely, recovery of viscoelastic fibers is typically described as a combination of immediate elastic recovery, delayed recovery, and permanent set or secondary creep. The permanent set is the residual extension that is not recoverable. These three components of recovery for acetate are given in Table 1 (4). The elastic recovery of acetate fibers alone and in blends has also been reported (5). In textile processing strains of more than 10% are avoided in order to produce a fabric of acceptable dimensional or shape stabiUty. 

Fiber Immediate elastic recovery, % Delayed recovery, % Permanent set, %... 

Although delayed cure cotton was the primary impetus in the rise to durable-press performance, the emergence of DP blends had the effect of reducing the importance of a tme delayed cure. The industry tended to revert back to precure fabrics and the utilisation of hot-head presses to set in creases, using the thermoplastic characteristics of the synthetic components as weU as a touch of recure from the hot-head presses. 

When a fiber is stressed, the instantaneous elongation that occurs is defined as instantaneous elastic deformation. The subsequent delayed additional elongation that occurs with increasing time is creep deformation. Upon stress removal, the instantaneous recovery that occurs is called instantaneous elastic recovery and is approximately equal to the instantaneous elastic deformation. If the subsequent creep recovery is 100%, ie, equal to the creep deformation, the specimen exhibits primary creep only and is thus completely elastic. In such a case, the specimen has probably not been extended beyond its yield point. If after loading and load removal, the specimen fails to recover to its original length, the portion of creep deformation that is recoverable is still called primary creep the portion that is nonrecoverable is called secondary creep. This nonrecoverable elongation is typically called permanent set. 

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