Water hardness distribution

Dishwashing foam stability performance of an LAS-based light-duty liquid (LDL) is strongly affected by the carbon chain distribution, by water hardness, and, under some conditions, by phenyl isomer distribution. Foaming characteristics of C)2 phenyl isomer blends have been reported previously for conditions where LAS is the single anionic surfactant in the formulation (phosphate-built laundry powder) and the level of residual water hardness is low [30,31]. Under these conditions the internal phenyl isomers of C,2 LAS gave better foam performance than the 2-phenyl isomer. 

Matrix extrapolation undertaken by this model means that the model calculates the free metal ion concentration as the toxic species, given a total metal concentration and site-specific conditions in terms of water hardness, DOC, salinity, and so on. As an example, according to the MINTEQ model, a type of water with a hardness of 10 mg/L CaC03, a DOC content of 10 mg/L, a total Zn concentration of 10 mg/L, and a variable pH gives a distribution of Zn species as given in Table 2.5. 

Several authors have described the effect of alkyl chain length on performance. For LAS, a widely used surfactant in LDLDs, the most important factor in the performance is the carbon chain distribution [87], The optimum chain length of LAS for foam stability in a typical LDLD formulation varies depending on water hardness. This is illustrated in Table 7.13 for a formulated product of 24% LAS, 6% AEOS, and 2% LMMEA. 

The structures of some common nonionic surfactants are shown in Figure 3.2. Ethoxylated alcohols are produced from the reaction of fatty alcohols with ethylene oxide, which results in a broad distribution in the number of EO units per molecules. These surfactants are generally excellent detergents, very mild, and less sensitive to water hardness ions, and also act as solubilizers. A typical ethoxylated alcohol used in LDLDs has approximately 9 EO units and a carbon chain length distribution centered around Cll. 

Pair energy distributions. Pair energy distributions represent another source of useful micro-thermodynamic information easily obtainable from computer simulations, but hardly measurable in real experiments. These functions, p(Eij), represent the probability density of finding a pair of water molecules that have some particular interaction energy under given thermodynamic conditions. Figure 4 shows such functions for several typical thermodynamic states of supercritical water. Similar distribution for normal liquid water under ambient conditions is also shown in Figure 4 for comparison. 

Second, as demonstrated by the results interacting lead pipes with water hardness and new water mains, much of the impact observed in Massachusetts was driven by a handful of cities on the upper end of the distribution Cities with very soft and corrosive water and/or cities with a high proportion of newly installed water mains had unusually high infant mortality rates. Perhaps the sample of cities from England included no cities with similarly corrosive water supplies and new lead piping. 

The particle size distributions were determined by means of laser diffraction (Particle Size Analyzer, Sympatek, model Helos KA). The filler suspensions were prepared under the same conditions as the corresponding flotation tests (pH, water hardness, collector concentrations, stirring conditions). The solid material concentration was between 40 and 100 mg/1. 

One utility of such diagrams is in the prediction of the hardness traverse along the cross section of a specimen. For example. Figure 11.19a compares the radial hardness distributions for cylindrical plain carbon (1040) and alloy (4140) steel specimens both have a diameter of 50 mm (2 in.) and are water quenched. The difference in hardenabil-ity is evident from these two profiles. Specimen diameter also influences the hardness distribution, as demonstrated in Figure 11.19h, which plots the hardness profiles for oil-quenched 4140 cylinders 50 and 75 mm (2 and 3 in.) in diameter. Example Problem 11.1 illustrates how these hardness profiles are determined. 

Occurs in the form of esters (glycerides) in oils and fats of vegetable and animal origin. Usually obt. from palm oil. Widely distributed in plants. Used in detn. of water hardness. Cryst. Mp 63-64°. Bp 390°, Bpjoo 268.5°, Bp,5 215°. 

The American Water Works Association (AWWA) Water QuaUty Goals recommend a maximum total hardness of 80 ppm for municipal purposes (19). Municipal softening plants, however, distribute waters containing 70—150 ppm the final quaUty is estabUshed based on such factors as pubHc demand and economics. 

In general, the water uptake of D films tended to be higher than that of / films, but a more significant difference was shown by microhardness measurements. The results obtained with all three vehicles showed that the D areas were significantly softer than the / areas and that the distribution of the hardness values corresponded to that of the resistances. It was concluded that these films have a very heterogeneous structure and that / and D areas are brought about by differences in crosslinking density within the film. 

Our first example of an application of the potential distribution formula [Eq. (5)] is in the calculation of the excess chemical potential of a simple hydrophobic solute dissolved in water (Hummer et al., 1998a, 2000), which we consider to be a hard-core particle that excludes all water molecules from its molecular volume. We note that these purely... 

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