Range of entrainment

Menaker There is old work by Kavanau in the 1960s (Kavanau 1962a,b) which has recently been repeated in hamster (Boulos et al 2002). This clearly shows that natural transitions in light/dark cycles increase the range of entrainment dramatically. The clock will entrain to T cycles much longer or shorter with natural transitions than it will with abrupt transitions. This has to mean something. It isn t clear what it means, but the complexity of the retinal input to the SCN must be functional at some level. Perhaps the function is in getting information about the rate of transition. 

In a series of experiments we have tested the type and range of entrainment of glycolytic oscillations by a periodic source of substrate realizing domains of entrainment by the fundamental frequency, one-half harmonic and one-third harmonic of a sinusoidal source of substrate. Furthermore, random variation of the substrate input was found to yield sustained oscillations of stable period. The demonstration of the subharmonic entrainment adds to the proof of the nonlinear nature of the glycolytic oscillator, since this behavior is not observed in linear systems. A comparison between the experimental results and computer simulations furthermore showed that the oscillatory dynamics of the glycolytic system can be described by the phosphofructokinase model. 

The model makes a number of specific and testable predictions. Entrainment is predicted to be possible only within a symmetric i nterval of driving frequencies, specifically oi-A[Pg.105]

By measuring the range of entrainment experimentally, one can nail down the... 

Wever, R.A. 1972. Virtual synchronization towards the limits of the range of entrainment. J. Theor. Biol. 36 119-32. 

Knitted wire mesh serves as an effective entrainment separator when it cannot easily be foiiled by sohds in the liquor. The mesh is available in woven metal wire of most alloys and is installed as a blanket across the top of the evaporator (Fig. ll-122d) or in a monitor of reduced diameter atop the vapor head. These separators have low-pressure drops, usually on the order of 13 mm [ M in) of water, and collection efficiency is above 99.8 percent in the range of vapor velocities from 2.5 to 6 iti/s (8 to 20 ft/s) [Carpenter and Othmer, Am. nsi. Chem. 

Stichlmair uses the ratio of actual velocity to this maximum velocity together with a term that increases entrainment as the distance gets small between the hquid-vapor layer and the tray deck above. His correlation spans a 10 fold range in entrainment. He shows a sharp increase in entrainment at 60 percent of the maximum velocity and attributes the increase to a shift to the spray regime. 

Flyash - Flyashes are finely divided matter generally entrained in flue gases that arise from combustion. Particles range from 1 /im in size on down. This is not within the operational range of gravity settling chambers. Wet... 

It is not uncommon to supply air into the room with jets attached both to the ceiling and to the wall surfaces. Air jets can be parallel to both surfaces or be directed at some angle to one or both surfaces (Fig. 7.28). Studies of compact wall jets supplied parallel to both surfaces reported by Grimitlyn show that the correction factor value is in the range from 1.6 to 1.7, which means that restriction of entrainment from two sides reduces velocity decay by 20% to 30% compared to the case of a wall jet. 

Generally the maximum allowable velocities are lower under conditions of pressure, and higher under conditions of vacuum. The limits and ranges of each area being determined by the relative operating densities of the vapor and liquid, the nature of the entrainment, and the degree of separation required. 

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