Introduction - Chemical Weathering

Chemical weathering of minerals results not only in the introduction of solutes to the aqueous phase but often in the formation of new solid phases. Dissolution is described as congruent, where aqueous phase solutes are the only products, or incongruent, where new solid phase(s) in addition to aqueous phase solutes are the products. These reactions... 

Another class of models relevant to chemical weathering is based on the reaction path approach originally developed by Helgeson et al. (1970). EQ3/EQ6 (Wolery et al. (1990), PHREEQC (Parkhurst and Plummer, 1993), and PATHARC.94 (Gunter et al., 2000) are some codes currently used to describe the progressive reaction of primary silicates and the precipitation of secondary phases as a function of time and mass. These codes are discussed in Nordstrom (see Chapter 5.02). They commonly permit the introduction of user-defined silicate reaction rates. Such models also commonly consider solubility controls on reaction kinetics as defined by... 

Nahon D. B. (1991) Introduction to the Petrology of Soils and Chemical Weathering. Wiley, New York. 

The introduction of high levels of drugs, enzymes, or chemicals may damage the biological components of the system. Cold weather can also reduce system efficiency. A greenhouse and source of artificial heat may be required in colder climates. 

The weight and strength properties of wood, together with the behavior of wood in response to weather, chemical treatment, fire, or microbial organisms, are influenced greatly by the wood s water content and the mass of wood tissue per unit volume (its density). The physical characteristics of wood tissue at given levels of moisture and density will be given specific attention in Chapter 3. However, some basic aspects of wood physics are included here to provide a more comprehensive introduction to the technical nature of solid wood. 

The results of this analysis can be arolied in the study of real systems in two ways. As mentioned in the Introduction, it may Ik used as a tool to predict weather impedance spectroscopy is senalive enough to monitor a specific phenomenon (e.j.diffusion) in a complex system. Also, one can use these results to chedc the consistency of experimental data with hypotheses concerning the physico-chemical modification of systems, as follows ... 

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