Extended wash ratio

Under mass production conditions, all hair samples are washed in an identical manner by the truncated wash procedure. This consists of one 15-min wash with dry isopropanol and three 1/2-h washes with phosphate buffer. Not aU hair samples will have reached plateau conditions by this procedure. To identify those samples which require further washing, we have defined two additional wash kinetic criteria " the curvature ratio, R, and the extended wash ratio, R w These are defined as follows ... 

Percentage Distribution of Extended Wash Ratio Values Using the Truncated Wash Procedure... 

Extended wash ratio Percentage distribution of positive samples ... 

Another aspect of our diagnostic algorithm that is not sufficiently appreciated is that the validity of the extended wash ratio and the safety zone ratio depends on the wash kinetics showing a significant amount of curvature as measured by the... 

The analysis for washing can be extended to a variety of modifications. These include simulation problems, use of efficiencies, calculation of maximum U/0 ratios, and calculations for cross-flow systems. The Kremser equation can also be applied to countercurrent washing with no additional assumptions. This adaptation is a straightforward translation of nomenclature and is illustrated in Example 14-1. Brian (1972) discusses application of the Kremser equation to washing in considerable detail. 

One application for SMEs and sulfonated fatty acids not usually found in the literature is soap bars. These can be personal wash/toilet bars or laundry bars. A 1942 patent discusses the use of SMEs in soap bars [41]. SMEs are also typically included in the extended list of anionic surfactants in more recent bar soap patents. However, they are rarely the focus of the patent. Sulfonated fatty acids do promote feel and improve smear properties [42,43]. More recently, the use of SMEs and sulfonated fatty acids in specific ratios was recommended [44]. 

During use, a product is stressed enough that after some time it can no longer be used (Fig. 13.4). Appropriate care (such as washing of textiles) can extend the life span of a product. A natural limit is set by the cost effor benefit or cost/effort ratio for a new product. 

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