Interpreting water analyses

A convenient method of interpreting water analysis for the purpose of determining the calcium carbonate solubility equilibrium conditions is embodied in the Langelier equation. The Langelier equation can be used to... 

A derived expression relating to the saturation point of calcium carbonate solubility in water. Used frequently to interpret water analysis in order to determine the potential for CaCC>3 supersaturation and deposition (scaling) and also by inference, but not always correctly, the opposite nonscaling potential (corrosion risk). Although LSI is scaleless, the industry generally accepts and promotes the following ... 

Most water analysis results are rather easily interpreted. However, two simple and useful tests need explanation. These are the P and M alkalinity. The water is titrated with N/30 HCl to the phenolphthalein end point at pH 8.3. This is called the P alkalinity. Similar titration to the methyl orange end point at pH 4.3 is called the M alkalinity. They are reported as ppm CaCO,. 

Note There are many different tests and different versions of the same test for water analysis. If there is any doubt as to method or interpretation consult a reputable water-treatment supplier. The letters ND in the table indicate not detectable. Parts per million (ppm) are also commonly used to express concentration and are essentially identical to mg/l. 

For larger plants some water analysis, results interpretation, and recommendations for operational changes may be carried out by a boiler operator, water treatment plant technician or a laboratory analyst (or even by an outsourced subcontractor) these recommendations complement similar work undertaken by the water treatment service company representative. 

It should not come as a surprise during the inspection that a boiler needs cleaning. Unfortunately, for the owners and operators of many smaller plants, it can be just that, simply because there are no MU water meters or steam charts installed, fuel consumption records are not studied, and water analysis sheets are not properly interpreted and proactive steps taken. 

This section covers some examples and notes on common but unrelated problems, all of which rely in part on the effective observation of boiler plant operating conditions and the interpretation of daily water analysis log sheets. 

Stiff, Jr. H.A., 1951. The interpretation of chemical water analysis by means of patterns. 

Zurcher F, Thuer M. 1978. Rapid weathering processes of fuel oil in natural waters Analysis and interpretations. Environ Sci Technol 12 838- 843. 

The absorption of light by the diphenylanthracene was found to result in efficient intracoil sensitization by fluorescene. The quantum efficiency of this process was determined to be 0.4 in methanol and 0.8 in water. This increase corresponds to a decrease in polymer coil size in water. Analysis of the fluorescence decay also demonstrates that the intracoil energy transfer is essentially a static process and that aggregation can result in nonexponential fluorescence decay that is interpreted as a dynamic equilibrium that takes place between diphenylanthracene and a nonfluorescent dimer state... 

Recently, many experiments have been performed on the structure and dynamics of liquids in porous glasses [175-190]. These studies are difficult to interpret because of the inhomogeneity of the sample. Simulations of water in a cylindrical cavity inside a block of hydrophilic Vycor glass have recently been performed [24,191,192] to facilitate the analysis of experimental results. Water molecules interact with Vycor atoms, using an empirical potential model which consists of (12-6) Lennard-Jones and Coulomb interactions. All atoms in the Vycor block are immobile. For details see Ref. 191. We have simulated samples at room temperature, which are filled with water to between 19 and 96 percent of the maximum possible amount. Because of the hydrophilicity of the glass, water molecules cover the surface already in nearly empty pores no molecules are found in the pore center in this case, although the density distribution is rather wide. When the amount of water increases, the center of the pore fills. Only in the case of 96 percent filling, a continuous aqueous phase without a cavity in the center of the pore is observed. 

Proper control of the properties of drilling mud is very important for their preparation and maintenance. Although oil-base muds are substantially different from water-base muds, several basic tests (such as specific weight, API funnel viscosity, API filtration, and retort analysis) are run in the same way. The test interpretations, however, are somewhat different. In addition, oil-base muds have several unique properties, such as temperature sensitivity, emulsion stability, aniline point, and oil coating-water wettability that require other tests. Therefore, testing of water and oil-base muds will be considered separately. 

A primary goal of this chapter is to learn how to achieve control over the pH of solutions of acids, bases, and their salts. The control of pH is crucial for the ability of organisms—including ourselves—to survive, because even minor drifts from the optimum value of the pH can cause enzymes to change their shape and cease to function. The information in this chapter is used in industry to control the pH of reaction mixtures and to purify water. In agriculture it is used to maintain the soil at an optimal pH. In the laboratory it is used to interpret the change in pH of a solution during a titration, one of the most common quantitative analytical technique. It also helps us appreciate the basis of qualitative analysis, the identification of the substances and ions present in a sample. 

X-Ray diffraction analysis of oriented polysaccharide fibers has had a long history. Marchessault and Sarko discussed this topic in Volume 22 of Advances, and a series of articles by Sundararajan and Marchessault in Volumes 33, 35, 36, and 40 surveyed ongoing developments. The comprehensive account presented here by Chandrasekaran (West Lafayette, Indiana) deals with some 50 polysaccharides, constituting a wide range of structural types, where accurate data and reliable interpretations are available. The regular helical structures of the polysaccharide chains, and associated cations and ordered water molecules, are presented in each instance as stereo drawings and discussed in relation to observed functional properties of the polymers. 

Qu et al. (2000) carried out experiments on heat transfer for water flow at 100 < Re < 1,450 in trapezoidal silicon micro-channels, with the hydraulic diameter ranging from 62.3 to 168.9pm. The dimensions are presented in Table 4.5. A numerical analysis was also carried out by solving a conjugate heat transfer problem involving simultaneous determination of the temperature field in both the solid and fluid regions. It was found that the experimentally determined Nusselt number in micro-channels is lower than that predicted by numerical analysis. A roughness-viscosity model was applied to interpret the experimental results. 

Here we revisit two important topics in limnology just to show that climate change studies that only include data from lakes are not applicable to reservoirs. Firstly, we show that temperature trends in reservoirs and lakes cannot be interpreted in the same way. Secondly, we show that drivers of the deep-water oxygen content in reservoirs and lakes can be very different. This last analysis will be used in the following section as the starting point for a new framework for climate change impact studies in reservoirs. 

Recently, a / -dodecapeptide was found to display a CD spectrum in water which was very similar to that assigned to the 12/10-helix, with a single maximum near 200 nm. Careful NMR analysis however, revealed a predominantely extended conformation without regular secondary structure elements [174]. This result stresses that the CD signature assigned to the 12/10-structure might not be unique and again (see Section 2.2.3.1) that CD spectra must be interpreted with caution. 

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