Model conceptual diagram

This model conceptually forms the theoretical basis for the later development of electrolyte additives, as evidenced by the success of CO2 and VC in suppressing the irreversible capacity in the initial cyclings. But so far as major electrolyte components are concerned, this model is not widely applied, since many other properties such as ion conduction and phase diagrams must also be taken into account if the component is present in high concentrations. 

Figure 3.1 Decomposition and carbon turnover in soil A conceptual diagram summarizing the main elements of the initial Rothamsted carbon model (Jen-kinson 1971). To this we have added other small, but potentially functionally important, compartments the volatile organic carbon and the dissolved organic carbon derived during both decomposition of litter and exudation from plants. An inert organic matter pool is added as this appears in later versions of the Rothamsted model.

Pharmacokinetic/pharmacodynamic modeling relates the dose or concentration (exposure) of a drug provided by the kinetic model to its observed pharmacological effects (response) by establishing an exposure-response relationship. The conceptual diagram of a typical PK/PD model is illustrated in Fig. 3. 

This model has been developed by Kemp et al (1995) and the conceptual diagram is shown in Figure 17. 

Figure 1. Conceptual diagram of the Unified Field Model. (Reproduced with premission from Ref. 15. Copyright 1980, American Industrial Hygiene Association.)...

Upon completion of both the preliminary and detailed site investigation, a conceptual model can be prepared. A conceptual model is essentially a site model which includes all of the information that has been acquired for the site from both preliminary and detailed investigations, as well as other investigations not directly related to the site. The conceptual model can be anything from simple diagrams to detailed computer simulations, depending ujran the complexity of the site. The model must be continually updated to include new information as it is developed. 

Various approaches and graphical conventions have been used in drawing conceptual model diagrams. Consideration could be given to recommending a standardized approach for use in probabilistic assessments. 

That conceptual model diagrams be constructed as a cascade of alternating processes and states... 

Careful construction of the conceptual model diagram, and the use of a tabular approach such as Table 2.1, should help to avoid these problems. The diagram should show clearly the point at which individual exposure is used to predict individual effects and the process by which individual effects are aggregated to generate the risk estimate. In addition, it should be remembered that the risk estimate may be combined quantitatively or qualitatively with other lines of evidence to address the assessment endpoint. 

Show at least the major uncertainties in the diagram of the conceptual model, linked to the model components they affect (e.g.. Figure 2.3). 

FIGURE 2.3 A simple approach to identifying variables, uncertainties, and dependencies in a conceptual model diagram. For key, see Table 2.2. 

There is a conceptual model of hydrated ions that includes the primary hydration shell as discussed above, secondary hydration sphere consists of water molecules that are hydrogen bonded to those in the primary shell and experience some electrostatic attraction from the central ion. This secondary shell merges with the bulk liquid water. A diagram of the model is shown in Figure 2.3. X-ray diffraction measurements and NMR spectroscopy have revealed only two different environments for water molecules in solution of ions. These are associated with the primary hydration shell and water molecules in the bulk solution. Both methods are subject to deficiencies, because of the generally very rapid exchange of water molecules between various positions around ions and in the bulk liquid. Evidence from studies of the electrical conductivities of ions shows that when ions move under the influence of an electrical gradient they tow with them as many as 40 water molecules, in dilute solutions. 

Diagrams can be used to illustrate the relationships described by the conceptual model and risk hypotheses. Conceptual model diagrams are useful tools for communicating important pathways and for identifying major sources of uncertainty. These diagrams and risk hypotheses can be used to identify the most important pathways and relationships to consider in the analysis phase. The hypotheses considered most likely to contribute to risk are identified for subsequent evaluation in the risk assessment. 

Figure 28.2 An example of a conceptual model for a watershed. Human activities, shown at the top of the diagram, result in various stressors that induce ecological effects. Assessment end points and related measures that are associated with these effects are shown at the bottom of the diagram.

Figure 2.13. Upper panel is a summary diagram of the standard model of metabolic regulation in this conceptualization, accelerating tissue ATP utilization leads to increasing concentrations of ADP and Pi, which serve as substrates for oxidative phosphorylation, to activate ATP production. Lower panel summarizes an alternate model of metabolic regulation in which ATP demand and ATP supply pathways are simultaneously activated during large-scale change in tissue work rates. See text for further details.

Fig. 8 Schematic diagram of the conceptual model showing the unidirectional velocity Ux, the DNAPL pool with aqueous saturation concentration Cs, the humic substance line source of height Lh> and the modes of interaction between dissolved contaminant, dissolved humic substances, and the solid matrix (adopted from Tatalovich et al. [57])...

Cotecchia et al. (1974) studied the salinization of wells on the coast of the Ionian Sea. A fingerprint diagram (Fig. 6.23) served to define a conceptual model. The lowest line (MT) is of a fresh water spring and the uppermost line (I.S.) is of the Ionian Sea water. The lines in between (SR and CH) are of groundwaters with increasing proportions of seawater intrusion. The CH well met the nondiluted seawater at a depth of 170 m. This interpretation seems to be well founded as it is based on six dissolved ions. The whole story is condensed into one fingerprint diagram. 

The observations discussed in light of the composition diagrams lead to the following conceptual model for the Kalahari groundwaters ... 

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