Threshold saturation

Threshold, Saturation, and Adaptation. Several aspects of flavor perception are not accounted for in the Weber-Stevens laws, eg. 

Figure 21. Oscilloscope picture showing photodiode response (change in optical transmittivity of the cell) to triangular pulses of opposite polarity (4 V peak-to-peak), demonstrating threshold, saturation, memory, and symmetry bistability cf. Fig. 11. The material is DOBAMBC at 60 X. Horizontal scale 1.5 V/div (from [95]).

The key to understanding dewatering by air displacement is the capillary pressure diagram. Figure 6 presents an example typical for a fine coal suspension there is a minimum moisture content, about 12%, called irreducible saturation, which cannot be removed by air displacement at any pressure and a threshold pressure, about 13 kPa. 

Saturation is the concentration of a stimulus above which no increase in perception can be detected. It is tme that Weber-Stevens laws can predict the relationship between stimulus intensity and sensory response with some precision however, they do not describe the very common situation of stimuli at or near the threshold or point of saturation. 

Because naphthalene vapors can cause eye irritation at concentrations of 15 ppm in air and because continued exposure may result in adverse effects to the eye, a threshold limit value of 10 ppm (50 mg/m ) has been set by the ACGIH (45). This amount is about 30% of the air-saturation value at 27°C. 

Several overall features of the shock-induced polarization are apparent. First, there appears to be a threshold compression below which the signals are not observed. The compression for this threshold is considerable, about 15%, such that it is not difficult to believe that the material must be considerably altered in structure before polarizations appear (shown in Fig. 5.22). Following the threshold compression, the polarizations increase extraordinarily rapidly with increasing compression, finally reaching a saturation value at compressions of perhaps 30%. 

Each oil-dispersant combination shows a unique threshold or onset of dispersion [589]. A statistic analysis showed that the principal factors involved are the oil composition, dispersant formulation, sea surface turbulence, and dispersant quantity [588]. The composition of the oil is very important. The effectiveness of the dispersant formulation correlates strongly with the amount of the saturate components in the oil. The other components of the oil (i.e., asphaltenes, resins, or polar substances and aromatic fractions) show a negative correlation with the dispersant effectiveness. The viscosity of the oil is determined by the composition of the oil. Therefore viscosity and composition are responsible for the effectiveness of a dispersant. The dispersant composition is significant and interacts with the oil composition. Sea turbulence strongly affects dispersant effectiveness. The effectiveness rises with increasing turbulence to a maximal value. The effectiveness for commercial dispersants is a Gaussian distribution around a certain salinity value. 

Raff Many of these experiments that suggest that cells have a size threshold are done in culture, with saturating amounts of extracellular signals that stimulate cell growth and cell cycle progression. In these conditions, cells will tend to be the same size, but these signals are not saturating in vivo. 

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