Theoretical systems analysis

However, theoretical system analysis may also refer to individual technical installations. This, under safety aspects, is called safety analysis. In other words, system analysis can be technology oriented (technology assessment) or installation oriented (safety analysis). 

Theoretical system analysis may be of a quantitative or a qualitative nature. In each case, quantitative analysis must be preceded by a qualitative analysis in order to discover relevant problems and recognize the areas where qualitative analysis must be complemented by quantitative analysis. Even then, a certain restriction will be necessary because of the scarcity of the possibilities at one s disposal, e.g., mathematical models, data, and computers. The instrument of quantitative theoretical system analysis is mathematical simulation. Due to its importance for modern safety analysis, this will be treated separately in the following section. 

By means of theoretical systems analysis, the effects of a new technology on society and the environment can be ascertained prior to its realization, and possible dangers which can be expected, together with the benelits, can be identified. This type of procedure, known as technology assessment, which will be explained in Section 9.1, has its limitations since it is not based on its own specific scientific methodology. However, in view of the serious and, under some circumstances, irreversible effects of a technical innovation, from case to case technology assessment cannot be waived. 

Since these initial contributions, many works followed, which may be classified into three broad categories (1) Control structure development based mainly on process experience and engineering judgment [7], (2) Control structure development that follows the guidelines of the steady-state process design synthesis hierarchy [1], and (3) Control structure development that relies on a mathematical formulation based on dynamic system theory, optimization, and control-theoretic systems analysis. Some contributions can be classified in more than one category. 

Tight turns were first recognized from a theoretical conformational analysis by Venkatachalam (1968). He considered what conformations were available to a system of three linked peptide units (or four successive residues) that could be stabilized by a backbone hydrogen bond between the CO of residue n and the NH of residue n + 3. He... 

In order to understand the above questions/paradoxes, a mode coupling theoretical (MCT) analysis of time-dependent diffusion for two-dimensional systems has been performed. The study is motivated by the success of the MCT in describing the diffusion in 3-D systems. The main concern in this study is to extend the MCT for 2-D systems and study the diffusion in a Lennard-Jones fluid. An attempt has also been made to answer the anomaly in the computer simulation studies. 

Chandrashekar, M. and Wong, F. C., "Thermodynamics Systems Analysis - 1. A Graphic-Theoretic Approach," Energy (Oxford), 539 (1982). 

A theoretical analysis of oxalate-carbonate transformation The objective of this theoretical approach is to try to compare the equilibrium diagrams of the CaCOs—CaC204—CO2—H2O system with the biogeochemical data available on the oxalate-carbonate transformation. The initial hypothesis is that the oxido-reduction reaction of oxalate-carbonate occurs biochemically, i.e. due to bacterial activity. In other words, activation energy is present and high enough to initiate the reactions. The theoretical system studied is defined by three different phases present ... 

Savageau, M. A. (1969a). Biochemical systems analysis I. Some mathematical properties of the rate law for the component enzymatic reactions. J. Theoret. Biol. 25, 365-369. 

There have been extensive experiments on the isomerization of stilbene and its derivatives (125, 126), none of which to date have received any serious theoretical numerical analysis. In this experiment, changes in pressure have caused changes of orders of magnitude in the rate. It is time that a serious molecular dynamics study of this system be undertaken. This might also be useful in understanding the importance of multidimensional effects, since typically, in an isomerization of a big molecule, one could expect that more than one angle participates strongly in the isomerization process. 

Specimens are loaded under drained conditions. Pore pressure is measured in order to check possible excess pore water pressure. Several times before failure, loading is stopped. Axial force is kept constant and when pressure equilibrium is installed through the specimen, permeability measurement is performed using a transient method the pulse technique. This method has been introduced by Brace et at. (1968) to measure very low permeability (less than 10 m"). The more classical steady state method is inadequate because of the very low flow induced. In addition the time to reach steady state can be very large, indicating stability problems in time (long term behaviour of the specimen, chemical effects). Theoretical data analysis of pulse method is based on the diffusion equation of pressure wave. The specimen is surrounded by two reservoirs and the system is under equilibrium (at the same water pressure). A pulse of pressure is created at one end of the specimen and the propagating wave induced is recorded at the other end. Pore pressure then reaches a new equilibrium. The shape of the wave... 

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