Detail, level Purpose

Production planning has to determine on the detailed level which production step (operation) has to be carried out at which time and on which resource. For this purpose a resource allocation problem has to be solved (this is denoted as a scheduling problem in mathematical theory). It is natural to desire this allocation to be optimal in a certain sense (minimal number of setups and/or violations of requirements dates, etc.). 

Recall from table 1.1 that audience and purpose are communicated through four subcomponents (conciseness, level of detail, level of formality, and word choice). The first of these, conciseness, is a hallmark of writing in chemistry. Chemistry readers (experts and nonexperts alike) want crisp, clean sentences that say what needs to be said and no more. They do not want to be bogged down in words that fail to advance or, worse, confuse meaning. Because concise writing is... 

Usually models are created for a certain purpose, and that purpose drives their structure, level of detail, level of complexity, etc. A model may be excellent, but it must not be used for inappropriate purposes. If the output of the model does not match the assessment endpoint and the questions raised in the problem formulation phase, then the model obviously is not suitable for the specihc case. 

Another class of methods, which is not listed in the classification proposed by Toschkoff and Khinast (2013) and which can be effectively appUed for modeling of industrial scale FBs, is a multiscale simulation approach. This methodology implies a combination of submodels and computational methods applied for process simulation on different time and length scales. According to Werther et al. (2011), the models of different apparatuses and processes in the solids industry can be distinguished by detailing levels and application purposes, whereby each level can only be applied to some specific application of modeling Fig. 1. 

A major difficulty in an inorganic text is to strike a balance between a short readable book and a longer, more detailed text which can be used for reference purposes. In reaching what we hope is a reasonable compromise between these two extremes, we acknowledge that both the historical background and industrial processes have been treated very concisely. We must also say that we have not hesitated to simplify complicated reactions or other phenomena—thus, for example, the treatment of amphoterism as a pH-dependent sequence between a simple aquo-cation and a simple hydroxo-anion neglects the presence of more complicated species but enables the phenomena to be adequately understood at this level. 

Analytical Approaches. Different analytical techniques have been appHed to each fraction to determine its molecular composition. As the molecular weight increases, complexity increasingly shifts the level of analytical detail from quantification of most individual species in the naphtha to average molecular descriptions in the vacuum residuum. For the naphtha, classical techniques allow the isolation and identification of individual compounds by physical properties. Gas chromatographic (gc) resolution allows almost every compound having less than eight carbon atoms to be measured separately. The combination of gc with mass spectrometry (gc/ms) can be used for quantitation purposes when compounds are not well-resolved by gc. 

Polymerization Reactions. Polymerization addition reactions are commercially the most important class of reactions for the propylene molecule and are covered in detail elsewhere (see Olefin polymers, polypropylene). Many types of gas- or liquid-phase catalysts are used for this purpose. Most recently, metallocene catalysts have been commercially employed. These latter catalysts requite higher levels of propylene purity. 

The purpose of this stage is to specify how underlying causes will be derived from plant data and the type and level of detail required to perform these... 

In order to identify and then establish the risk level of a chemical, one uses a certain number of risk parameters. The purpose of this chapter is to consider these parameters in detail. It is also to enable the reader to submit these parameters to critical analysis if values are available, or to estimate them if they are unknown. The user of this book should then be able to offer an evaluation of the risk level of inflammability of a particular chemical. This is necessary even if the chemical is not in the tables included later in this book. 

Ab initio atomic simulations are computationally demanding present day computers and theoretical methods allow simulations at the quantum mechanical level of hundreds of atoms. Since an electrochemical cell contains an astronomical number of atoms, however, simplifications are essential. It is therefore obvious that it is necessary to study the half-cell reactions one by one. This, in turn, implies that a reference electrode with a known fixed potential is needed. For this purpose, a theoretical counterpart to the standard hydrogen electrode (SHE) has been established [Nprskov et al., 2004]. We will describe this model in some detail below. 

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