Group-specific component description

The main, currently used, surface complexation models (SCMs) are the constant capacitance, the diffuse double layer (DDL) or two layer, the triple layer, the four layer and the CD-MUSIC models. These models differ mainly in their descriptions of the electrical double layer at the oxide/solution interface and, in particular, in the locations of the various adsorbing species. As a result, the electrostatic equations which are used to relate surface potential to surface charge, i. e. the way the free energy of adsorption is divided into its chemical and electrostatic components, are different for each model. A further difference is the method by which the weakly bound (non specifically adsorbing see below) ions are treated. The CD-MUSIC model differs from all the others in that it attempts to take into account the nature and arrangement of the surface functional groups of the adsorbent. These models, which are fully described in a number of reviews (Westall and Hohl, 1980 Westall, 1986, 1987 James and Parks, 1982 Sparks, 1986 Schindler and Stumm, 1987 Davis and Kent, 1990 Hiemstra and Van Riemsdijk, 1996 Venema et al., 1996) are summarised here. 

Chapter 5 contains a description of the evaluation of substance classes that can be detected from their own color or fluorescence or from components that absorb UV light. Compounds that do not show such properties must be converted into other substances (derivatives) that are detectable in order to evaluate a TLC separation, i.e. they must be derivatized. These can be universal reactions or, if suitable functional groups are present, they can be selective. Substance-specific derivatizations are practically impossible. 

The latest development in food technology is the manufacture of engineered products. Additives are often used as functional components [B.71] to obtain materials with specific, predetermined, and controlled properties. They are formulated from particulate ingredients and then agglomerated to yield consumer products that feature desirable characteristics. For the new food groups, descriptive names have been coined during the past years [B.97]. 

Figure 61 lists a small number of general stmctural component properties. Each particular structural component has specific properties, making it practically impossible to provide a detailed description of properties for all structural components. They can be divided into groups, for instance body parts, seals, toys, electronics components, etc. 

This text does not explain toierancing as an activity of mechanical design it just outlines the advanced description and analysis of tolerances in integrated part and assembly models. Because manufacturing processes have some level of errors and more precise manufacturing is much more expensive, dimensions must be defined with a tolerance specification in accordance with the requirements of the operation and manufacturing of the product. However, tolerance cannot be evaluated for an individual dimension but for purposeful chains of dimensions. For this purpose, dimensions are grouped in chains with component and resultant dimensions. 

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