Levels of Detail

To give some structure to the process design it is common to present information and ideas in the form of process flow schemes (PFS). These can take a number of forms and be prepared in various levels of detail. Atypical approach is to divide the process into a hierarchy differentiating the main process from both utility and safety processes. 

For example a process flow scheme for crude oil stabilisation might contain details of equipment, lines, valves, controls and mass and heat balance information where appropriate. This would be the typical level of detail used in the project definition and preliminary design phase described in Section 12.0. 

This section has focused mainly on the internal dynamics of small molecules, where a coherent picture of the detailed mtemal motion has been emerging from intense efforts of many theoretical and experimental workers. A natural question is whether these kinds of issues will be important m the dynamics of larger molecules, and whether their investigation at the same level of detail will be profitable or tractable. 

Molecular spectroscopy offers a fiindamental approach to intramolecular processes [18, 94]. The spectral analysis in temis of detailed quantum mechanical models in principle provides the complete infomiation about the wave-packet dynamics on a level of detail not easily accessible by time-resolved teclmiques. 

The methodology presented so far allows the calculations of state-to-state. S -matrix elements. However, often one is not interested in this high-level of detail but prefers instead to find more average infomiation, such as the initial-state selected reaction probability, i.e. the probability of rearrangement given an initial state Uq. In general, this probability is... 

Molecular dynamics (MD) metliods can be used to simulate tribological phenomena at a molecular level. These have been used primarily to simulate behaviour observed in AFM and SFA measurements. Such simulations are limited to short-timescale events, but provide a weaitli of infonnation and insight into tribological phenomena at a level of detail tliat cannot be realized by any experimental metliod. One of tire most interesting contributions of molecular dynamics... 

At one time, computational chemistry techniques were used only by experts extremely experienced in using tools that were for the most part difficult to understand and apply. Today, advances in software have produced programs that are easily used by any chemist. Along with new software comes new literature on the subject. There are now books that describe the fundamental principles of computational chemistry at almost any level of detail. A number of books also exist that explain how to apply computational chemistry techniques to simple calculations appropriate for student assignments. There are, in addition, many detailed research papers on advanced topics that are intended to be read only by professional theorists. 

The section on applications examines the same techniques from the standpoint of the type of chemical system. A number of techniques applicable to biomolecular work are mentioned, but not covered at the level of detail presented throughout the rest of the book. Likewise, we only provide an introduction to the techniques applicable to modeling polymers, liquids, and solids. Again, our aim was to not repeat in unnecessary detail information contained elsewhere in the book, but to only include the basic concepts needed for an understanding of the subjects involved. 

Other methods are also used to contrast the regions of an orbital where the signs of the wave function are differ ent Some mark one lobe of a p orbital + and the other — Others shade one lobe and leave the other blank When this level of detail isn t necessary no differentiation IS made between the two lobes... 

For a quantum mechanical calculation, the single point calculation leads to a wave function for the molecular system and considerably more information than just the energy and gradient are available. In principle, any expectation value might be computed. You can get plots of the individual orbitals, the total (or spin) electron density and the electrostatic field around the molecule. You can see the orbital energies in the status line when you plot an orbital. Finally, the log file contains additional information including the dipole moment of the molecule. The level of detail may be controlled by the PrintLevel entry in the chem.ini file. 

However, even if there is some disclosure of the invention in the prior activity, the law of patents in the United States requires a high level of detail concerning the invention. A summary of factors to consider in establishing that an invention is not obvious is as foUows ... 

A hierarchical design procedure for process synthesis can be used in conjunction with a flow-sheeting program to analyze, evaluate, and optimize the options (60). The emphasis is on starting with the simplest possible models that will give answers to a particular question quickly so that the questions to be asked at the next decision level can be formulated. At each stage, it is necessary to ensure that the level of detail in the model is sufficient to give rehable information. 

Who needs training for this process and to what level of detail ... 

The standard operating procedures demand great attention as they reflect personnel safety issues, safe operating limits and quality considerations. They should be written simply and clearly. The level of detail is determined by the training and experience of the operations staff but should also take into account the hazards inherent in the process. 

If special materials of construction are needed, provisions need to be in maintenance procedures to make sure these materials are used. If there are prohibitions on certain materials of construction, the procedures need to have provisions to make sure that they are not used. These considerations are especially true if there are multiple operations involved in the tolling unit. Answering the questions below can help determine which maintenance procedures need to be written and the level of detail required ... 

Emergency response plan procedures may need to be evaluated against new material hazards introduced by the toll. This is primarily a concern when the toller is handling a feedstock or product that introduces hazards that may not have been present previously at that facility. Most emergency response plan procedures are written at a high enough level of detail that they will be unaffected, but it is necessaiy to evaluate the plan s adequacy. 

The question to answer for this pre-startup task is Who needs training for this process and to what level of detail One method to analyze training needs is offered by the Instructional Systems Design (ISD) technical training model. It points to the job task analysis method mentioned previously (Appendix D, ISD Model and Job Task Analysis Techniques) to identify procedure titles as a first step for determining which job positions require specific knowledge and skills. 

Revisit the operating procedures to ensure they are written to the appropriate level of detail for the new operators. 

The initial incident report is very important. This document captures the initiator s firsthand knowledge of what occurred in the moments after the specific event. Example 5-2, Sample Toller Initial Incident Report, is an example of the data that should be documented as soon as possible. Note that it should be modified using the company s management system procedure and incident investigation procedure, which should describe the type of data needed, and level of detail desired. 

The level of effort required for a frequency analysis is a function of the complexity of the system or process being analyzed and the level of detail required to meet the analysis objectives. Frequency analysis can typically require 25% to 50% of the total effort in a large-scale QRA study. If an uncertainty analysis is performed, the effort required for the frequency analysis can be much greater. 

Return to step 1 and refine the two intermediate segments in the same manner, and so on, until the desired level of detail is obtained. 

Although the folding of short proteins has been simulated at the atomic level of detail [159,160], a simplified protein representation is often applied. Simplifications include using one or a few interaction centers per residue [161] as well as a lattice representation of a protein [162]. Some methods are hierarchical in that they begin with a simplified lattice representation and end up with an atomistic detailed molecular dynamics simulation [163]. 

The current understanding of the protein folding process has benefited much from studies that focus on computer simulations of simplified lattice models. These studies try to construct as simple a model as possible that will capture some of the more important properties of the real polypeptide chain. Once such a model is defined it can be explored and studied at a level of detail that is hard to achieve with more realistic (and thus more complex) atomistic models. 

To conclude, although the models used in lattice simulations are very simplified, the results provide general information on possible protein folding scenarios, albeit not on the detailed behavior of specific proteins, which would require more complex models and more accurate potentials. The contribution made by these simulations is that they enable an analysis of the structures, energetics, and dynamics of folding reactions at a level of detail not accessible to experiment. 

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