Instantaneous flux

The winding that is static is termed a stator and that which rotates is a rotor. If l is the rotor current and 0 the instantaneous flux, then the force in terms of torque, T, produced by these parameters can be expressed by... 

The instantaneous flux at the surface of the bubbles in subreactor j will thus be given by (G7) Eq. (176). 

This result gives the flux for a small portion of the surface that has been exposed for exactly t seconds. Other portions of the surface will have been exposed for different times and thus will have different instantaneous fluxes. To And the average flux, we need the differential distribution of exposure times,/(f). Danckwerts assumed an exponential distribution ... 

Compute the advantage factor for using a reactor pulse to produce 20-s 46Scm compared to the activity produced by steady-state irradiation. Assume the reactor is of the TRIG A type and produces a 15-ms 3000-MW pulse with a peak instantaneous flux of 21 x 1015 n/cm2-s. Assume steady-state operation is at 1 MW. 

FIGURE 15.1 Instantaneous flux of estradiol through human epidermal membrane. Membranes were electroporated by either 5 x 100 V pulses with a pulse width of 100 ms (closed symbols) or 50 x 100 V pulses with a pulse width of 10 ms (open symbols) (n — 3). 

Results are presented as instantaneous fluxes versus time plots for estradiol and L-glutamic acid in Figure 15.3 and Figure 154, respectively. Apparent fluxes for the two permeants during three stages of the experiment are also shown in Table 15.2, along with respective enhancement and DRs. 

FIGURE 15.3 Instantaneous flux profiles of estradiol through human epidermal membrane during a three stage experiment. Electrical procedures were iontophoresis (0.8 mA/cm2), electroporation (5 x 100 Y pulses with a pulse width of 100 ms), or electroporation followed by iontophoresis (n = 5-9). 

This is the solution for an instantaneous flux rate at the interface, since we are considering dilute solutions any diffusion-induced convection can be neglected. This means that the total mole flux is equal to the diffusion flux, and that we can write the instantaneous mass transfer rate directly in the form derived for the diffusion flux ... 

Further retaxation of the assumptions of the film aed penetration theories was suggested by Danckwerta1 who viewed the process as one of transient one-dimensioual diffusion to packets or elements of fluid that reside at the phase interface for varying periods of time. Therefore, the model is that of the penetration theory with a distribution of conract times, The surface age distribution p(t) is defined such that 4(i)tb is the fraction of surface that has seslded at the interface for a time between I and t + di. The mass transfer flua for the entire surface is obtained by integration or the instantaneous flux over all exposure times ... 

The most critical parameter in the characterisation of membranes is their flux. For the characterisation of clean membranes flux is measured with MilliQ water as pure water flux . The definition of the instantaneous flux is given in equation (3.2), where V is the filtrate volume, t the filtration time, and A the membrane surface area. 

Johnstone and Pigford obtained a series solution to the above problem using the complete velocity profile. For short contact times, the diffusing solute effectively encounters only the fluid moving at the surface velocity (v ) since It has penetrated into the film only a short distance. Under these circumstances the solution for tin composition profile is obtained in terms of the error function and the instantaneous flux into the liquid is given by... 

Instantaneous flux over a 3 msec wide pulse. 

FIGU RE 13.15 The ratio of the number of ablated and cooled ytterbium atoms to the number emitted into the beam for a simple slit aperture (no suppressor nozzle). At high buffer-gas densities, which correspond to long diffusion times and therefore high (see main text), up to 40% of the cold ablated atoms are detected in the peak instantaneous flux represented here of 5 X 10 atom/sec sr . (From Patterson, D., and Doyle, J.M., J. Chem. Phys., 126, 154307, 2007. With permission.)... 

Abstract Instantaneous distribution of mass and thermal fluxes inside and outside of an evaporating sessile droplet is considered using computer simulations. The latter distribution is calculated in a self consistent way by considering an intercoimected problem of vapour transfer in the vapour phase outside the droplet heat transfer in vapour, liquid and solid substrate and Marangoni convection inside the liquid droplet. The influence of thermal conductivity of the solid support on the evaporation process is evaluated. The deduced dependences of instantaneous fluxes can be applied for self-consistent calculations of time evolution of the evaporation processes of sessile droplets. 

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