Boundaries, phase studies, definition

The particular experimental studies, which have been described here, have provided a basis for a practical definition of the boundary of the mobile phase in coals, and some tentative clues to the nature of its association with the network. Inevitably, other research techniques will bring different perspectives. 

In the inventory phase the boundaries between the inputs from and the outputs to the environmental system and the boundaries between the product system under study and other product systems are specified. In this stage three elements may be distinguished the definition of the processes of the product system the specification of all processes and their data and the compilation of the inventory tables. 

Although the number of valence electrons present on an atom places definite restrictions on the maximum formal oxidation state possible for a given transition element in chemical combination, in condensed phases, at least, there seem to be no a priori restrictions on minimum formal oxidation states. In future studies we hope to arrive at some definitive conclusions on how much negative charge can be added to a metal center before reduction and/or loss of coordinated ligands occur. Answers to these questions will ultimately define the boundaries of superreduced transition metal chemistry and also provide insight on the relative susceptibility of coordinated ligands to reduction, an area that has attracted substantial interest (98,117-119). 

The second task involves defining the boundaries within which the model was derived and can be expected, without further motivation, to be an adequate description of the data. Within these bounds the model can replace the raw data (after all, the model is supposed to capture all salient features of the data), which will be useful when presenting the knowledge summarized by the developed model to nonpharmacometricians. The definition of these bounds can be based on the inclu-sion/exclusion criteria of the study or the realized covariate distribution. In the latter case, some of the exploratory plots from the before-analysis phase are useful. 

The International Standard Organization (ISO 14040) [26] breaks the LCA framework into four main stages (1) Goal and scope definition of the study. This stage clarifies the purposes of carrying the study while the assumptions and system boundaries are described clearly. (2) Life Cycle Inventory (LCI) analysis. LCI involves data collection and calculation procedures to quantify relevant inputs and outputs of the entire system defined within the system boundaries. (3) Life cycle impact assessment involves qualifying the potential environmental impacts of the inventory analysis results. (4) The interpretation of the results from the previous phases of the study in relation to the objective of the study. This interpretation can be in form of conclusions and recommendations to decision-makers for process changes to deliver improvement in the environmentel performance. 

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