Water loss, separators

The egg shell is 94% calcium carbonate [471-34-17, CaCO, 1% calcium phosphate [7758-23-8] and a small amount of magnesium carbonate [546-93-0]. A water-insoluble keratin-type protein is found within the shell and in the outer cuticle coating. The pores of the shell allow carbon dioxide and water to escape during storage. The shell is separated from the egg contents by two protein membranes. The air cell formed by separation of these membranes increases in size because of water loss. The air cell originally forms because of the contraction of the Hquid within the egg shell when the temperature changes from the body temperature of the hen at 41.6°C to a storage temperature of the egg at 7.2°C. 

The closest relative to the wood veneer surprisingly has retained some of its properties, which differentiate these separators from pure synthetic ones primarily, a positive effect in reducing the water loss in starter batteries [39, 70-72], This impact tends to decrease as the antimony content in the alloys is lowered, but it still represents an advantage over other leaf separators, unless a microporous pocket is required by the alloy anyway. 

Surprisingly the water consumption of a starter battery, provided it contains anti-monial alloys, is affected by the separator. Some cellulosic separators as well as specially developed polyethylene separators (e.g., DARAMIC V [76]) are able to decrease the water consumption significantly. The electrochemical processes involved are rather complex and a detailed description is beyond the scope of this chapter. Briefly, the basic principle behind the reduction of water loss by separators is their continuous release of specific organic molecules, e.g., aromatic aldehydes, which... 

Special applications are often governed by different priorities as already discussed in relation to golf carts, the low water loss and the delay in antimony poisoning in heavy-duty service of a forklift are of eminent importance, with the result that rubber separators remain the preferred product there. Submarine batteries offer a different... 

In the case of trace metals, adsorption is typically much faster than the time intervals for which it is practically possible to separate the cells. Therefore, in practice, values of kf and kr are most often estimated by assuming that water loss from the hydrated cation is rate-limiting (Eigen-Wilkins mechanism, see Section 4.3.1 above). In some cases, uptake transients can be observed at the start of a short-term uptake experiment or by using pulse-chase experiments for which a metal solution containing a radioactive tracer is replaced by a solution... 

All of the disadvantages of throwaway flue gas treatment systems can be lessened considerably by minimizing the amount of waste material produced. This can be accomplished by the choice of an effective sorbent material and the use of sorbent recycle to increase utilization. In turn, sorbent recycle can be optimized by the use of a separation process to remove the spent sorbent from unreacted sorbent. As water usually contributes significantly to the mass of the waste produced, the dewatering characteristics of the waste material are important. Efficient dewatering will not only minimize water losses but also reduce the disposal space required. 

The acetonitrile layers are mixed and poured into another separatory funnel. In cases of dimethoate, Dasanit, phosphamidon and DDVP poisonings, the three acetonitrile fractions are combined and evaporated to dryness, and the residue is taken up in one milliliter of acetone. Further extraction of acetonitrile is avoided as this results in appreciable loss of pesticides. The acetonitrile layer is diluted with water to ten times of its original volume. Twenty-five ml. of saturated sodium sulfate solution is added to this solution and extracted three times with twenty-five milliliter-portions of n-hexane previously saturated with distilled water. The separated n-hexane layers are combined and then concentrated to two milliliters on a warm water bath. 

Isotope effects have been separated from randomisation in water loss from isonicotinic acid. The water loss involves exchange of hydroxyl and j3-hydrogens and it was found that the isotope effect increased with decreasing internal energy being 1.6, 2.0 and 2.3 for source reactions, first and second field-free region metastable ions, respectively [641]. 

It should be repeated that in such processes the carbonium ion itself has only a very transitory existence. The loss of the /8-proton probably occurs at the instant the water molecule separates from the oxonium ioiy... 

Other examples of reaction occurring in advance of the product recrystallization interface include the dehydrations of NiS04.6H20 [91] and of Ca(OH)2 [92]. For dehydration reactions, a complete sequence of types of behaviour can be distinguished, based on the degree of separation of the zones of water loss and of product recrystallization. This pattern of reactivity may have wider application. 

Homogeneous reaction. The occurrence of water loss throughout the bulk of the crystal has been discussed [172], This may be followed by recrystallization by a separate rate process (as in 1(c) and l(d))[171]. 

Water loss is identified [13] as being diffusion controlled across a dehydration layer of significant thickness that advances into the reactant particles (see Figure 8.1.). The Ca(OH)2 structure is maintained during the greater part of reaction [14]. The rate of this reaction is more deceleratory than the requirements of the contracting volume equation and data satisfactorily fit the first-order equation. The anhydrous residue later recrystallises to CaO but the principal water elimination zone and the phase transformation interface are separated and may advance independently. 

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