Haze, temperature dependence

Hence, extrapolating to 100 C, the refractive index would be about 1.375 which is a sizable change in refractive Index units. Although the refractive indicies may be matched at room temperature, at elevated temperature there develops a mismatch and consequently there is an increase in haze. The new silica filler compositions show some temperature dependent haze, however not to as great an extent as compositions which depend upon matched refractive indices to achieve optical clarity. Table IX shows these differences in temperature dependent haze. For applications which require optical transparency over a range of temperatures, the new silica filled compositions offer a distinct advantage. 

This evidently accounts for the presence of isoprene in the breath.34 Isoprene is also formed by many plants and is released into the atmosphere in large amounts, which contribute to photochemical formation of haze. A Mg2+-dependent enzyme catalyzes the elimination of pyrophosphate.35 Isoprene emissions rise with increasing temperature, and it has been suggested that the isoprene may dissolve in chloroplast membranes and in some way confer increased heat resistance.36 37 Hydrolytic dephosphorylation can lead to dimethylallyl alcohol, which is oxidized in the liver to dimethy-lacrylyl-CoA (Eq. 22-1). 

The success of gelatin fining essentially depends on the temperature of the juice. At low temperature (less than 7°C) the gelatin does not flocculate completely (so hazes may develop later). The process should therefore be carried out at temperatures around 15°C. 

From the phase behavior of both binary mixtures (water-amphiphile and oil— amphiphile), it is now possible to account, at least qualitatively, for the three-component phase diagram as a function of temperature. The presence of a haze point on the oil-amphiphile phase diagram (critical point a) at temperature Ta shows that the surfactant is more compatible with the oil at high than at low temperature. The presence of a cloud point on the water-amphiphile phase diagram (the lower critical point (>) at temperature Tjj shows that (at least in the neighborhood of the temperature domain) the amphiphile is less compatible with water at high than at low temperature. As a consequence (the other parameters being kept constant), the amphiphile behavior depends on temperature. 

The polymer melt flows through a die to the next process step flat, circular, or slot dies are preferred. The flow through the die must be uniform across the exit plane. However, this is complicated by the nonlinear dependence of melt viscosity on both temperature and shear rate in the die (23,24). The suitability of a material is determined by measuring the flow properties with a capillary rheometer in the temperature and shear-rate range expected. Melt elasticity can cause flow instabilities, which affect haze and thickness (27,28) or the operation of downstream equipment. Exit melt velocity, flow characteristics, and quenching rate may impart significant orientation to the polymer. In some instances, melt orientation is reduced in others, it is maintained by quenching. 

Nonionic ethoxylated surfactants can also be used to produce isotropic W/O microemulsions. A low HLB number surfactant may be dissolved in an oil, and such a solution can solubilize water to a certain extent, depending on surfactant concentration. If water is added above the solubilization limit, the system separates into two phases W/O solubilized - - water. If the temperature of such a two-phase system is reduced an isotropic W/O microemulsion is formed below the solubilization temperature. If the temperature is then further reduced below the haze point, sep-... 

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