Modeling, of nature

The introductory chapter of this book identified four basic motivations for studying CA. The subsequent chapters have discussed a wide variety of CA models predicated on the first three of these four motivations namely, using CA as... (1) as powerful computational engines, (2) as discrete dynamical system simulators, and (3) as conceptual vehicles for studying general pattern formation and complexity. However, we have not yet presented any concrete examples of CA models predicated on the fourth-and arguably the deepest-motivation for studying CA as fundamental models of nature. A discussion of this fourth class of CA models is taken up in earnest in this chapter, whose narrative is woven around a search for an answer to the beisic speculative question, Is nature, at its core, a CA "... 

Abramova, A. V., Slivinsky, Ye. V., Goldfarb, Y.Y., Kitaev, L. Ye., Kubasov A. A., Modeling of Nature and Strength of Acid Centres in Ultrastable Zeolites as a Component of Hydrocracker Catalysts, in Hydrotreatment and Hydrocracking of Oil Fractions. 1999, Elsevier Science B. V New York. pp. 377-380. 

Models of natural waters calculated assuming redox disequilibrium generally require more input data than equilibrium models, in which a single variable constrains the system s oxidation state. The modeler can decouple as many redox pairs as can be independently constrained. A completely decoupled model, therefore, would require analytical data for each element in each of its redox states. Unfortunately, analytical data of this completeness are seldom collected. 

Runnells, D. D. and R. D. Lindberg, 1990, Selenium in aqueous solutions, the impossibility of obtaining a meaningful Eh using a platinum electrode, with implications for modeling of natural waters. Geology 18, 212-215. 

Jantzen, C.M. and Plodinec, M.J. (1984). Thermodynamic model of natural, Medieval and nuclear waste glass durability. Journal of Non-Crystalline Solids 67 207-223. 

Guy R. D., Chakrabarti C. L., and Schraumm L. L. (1975). The application of a simple chemical model of natural waters to metal fixation in particulate matter. Canadian Jour. Chem., 53 661-669. 

The idea of a fully deterministic world received its final blow from the modem physics of the twentiest century. Quantum mechanics abandoned the model of complete determinism. From a pragmatic point of view it is not relevant whether nature is inherently nondetermini Stic (as quantum theory states) or whether randomness is just a consequence of the complexity of natural systems. In fact, most descriptions (or models) of natural processes are made up of a mixture of deterministic and random elements. 

When the initial discoveries about atoms were being made, scientists based their conclusions on experimental evidence, and such evidence is always open to critical review. Investigators were thus able to look beyond the biases of the past to conceive new and more accurate models of nature. 

Numerous systems of this type, such as the carotenoid-porphyrin-quinone triad 94 [8.62a] (for PeT in a pentad see [8.62b]), have been extensively studied in many laboratories from the photochemical point of view and as models of natural photosynthetic centres [8.62-8.69, A. 10, A.20], especially in order to achieve very fast charge separation [8.69] and slow recombination, for instance in multiporphyrin... 

Model of Natural Draft Cooling Tower Performance Winiarski, L. D. Tichenor, B. A. 

Wershaw, R. L. (2004). Evaluation of conceptual models of natural organic matter (humus) from a consideration of the chemical and biochemical processes of humification. Scientific Investigations Report 2004-5121, U.S. Geological Survey, Reston, VA. 

Gulyaev Yu.V. Rogalsky V.I. Krapivin V.F. Novitchikhin E.P. and Yushkov V.P. (1991). Mathematical Modeling of Natural Objects in Global Space System of Ecological Control. Institute of Radioengineering and Electronics, Russian Academy of Sciences, Report No. 2(553), Moscow, 33 pp. [in Russian]. 

We need fossils and we need them badly. But discovery has many facets and it is imperative that the various aspects come together from different and independent efforts to average out an individual s bias creators of models of nature may be great guides through the minefields of ideas but they are never good scouts for evidence. The perils are not so much poisonous snakes and yellow fever as the capacity for self-deception. 

First, we should note that in practice experiment does not automatically trump calculations calculations which are considered to be reliable have been used to correct experimental results - or rather experimental claims, in contrast to confirmed experiments. Examples of this are the (likely) correction of dubious bond energies [1] and heats of formation [2], So the interesting question is, why should confirmed experiments take precedence in credibility to calculations Remove the quotation marks and the question almost answers itself as scientific realists [3] we believe that a good experiment reflects a reality of nature a calculation, on the other hand, is a kind of model of nature, possibly subject to revision. 

It is worth noting at this point that the various scientific theories that quantitatively and mathematically formulate natural phenomena are in fact mathematical models of nature. Such, for example, are the kinetic theory of gases and rubber elasticity, Bohr s atomic model, molecular theories of polymer solutions, and even the equations of transport phenomena cited earlier in this chapter. Not unlike the engineering mathematical models, they contain simplifying assumptions. For example, the transport equations involve the assumption that matter can be viewed as a continuum and that even in fast, irreversible processes, local equilibrium can be achieved. The paramount difference between a mathematical model of a natural process and that of an engineering system is the required level of accuracy and, of course, the generality of the phenomena involved. 

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