Requirements and Constraints

The designers of a new material follow a checklist. First they look at why the new material is needed what is its purpose, what functions are required, which properties must it have and not have, what fabrication methods are permitted, what resources are necessary and their cost, what is the availability of necessary elements. 

In design, there are steps that gradually narrow down the number of possible materials by imposing additional constraints. In each of them the success of the final design depends on originality, not on mechanically following a checklist, although that may help  

The first step is to survey the requirements. A list of purposes is created and constraints derived from product requirements and uses envisaged. Which features are wanted in the material and what is unwanted  

Then a list is made of all existing materials that have intrinsic properties that come close to the ones wanted. It should also include materials that only meet some of the requirements. The undesirable features of each possibility must be explicitly noted and perhaps also some seemingly irrelevant features that might come in useful later. 

The third step is to make a list of the extrinsic modifications (morphology, purity) that would improve the performance of the materials that come out of step 2. Materials are combined in composites to form so-called sum and product properties that improve properties or eliminate unwanted characteristics. The result of this step is a list of potentially suitable materials and composites, including the compounds that make them up and their microstructures. 

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Some special requirements and constraints of this example are ... 

The first paper. Challenges Associated With the Design of Oil-Gas Separation Systems for North Sea Platforms" by Penick and Thrasher, discusses and reviews the different design aspects, requirements, and constraints associated with oil and gas separation facilities in the North Sea. Specifications of crude-oil vapor pressure and gas dewpoint are reviewed from a pipeline standpoint, and potential solutions and design approaches to meet the separation objectives are presented. 

This paper first discusses critical infrastructures, its relation with security concepts, and the features that are relevant for understanding the challenges they pose to society. Then, the critical information infrastructure is analyzed, with reflections on the requirements and constraint for its protection, and the... 

Reversible immobilization is a relatively new approach for immobilizing the catalytic component. Table 3 indicates the various interactions that could be explored for this purpose. Their usefulness is largely unexplored for reversible immobilization and individual researchers should consider their individual requirements and constraints before adopting any one of them for their purposes. 

The process requirements and constraints are summarized in Fig. 6. The distinctive aspects of this problem definition are the large delay in measurement response due to the sampling arrangement employed, the tight constraint on total volume of the treatment system, and the presence of tanks upstream and downstream which assist in meeting the specification. 

The properties of thin films in automotive sensors often have to meet different requirements than those in microelectronics. In general, the electrical properties are of less importance than the mechanical properties. The special requirements and constraints for the materials are detailed below. 

It is important to recognize that environmental scientists make measurements for a variety of reasons, each of which imposes its own requirements and constraints on the instrumentation and measurement systems to be used. General environmental measurement modes include exploratory mapping and surveying, process investigations, baseline establishment and trend monitoring, and emission-deposition and other flux measurements. Table 1 lists some of the goals that drive each mode of measurement and some of the measurement system capabilities that they require. 

Among the sub-systems mentioned above, the design of the electrode array (also called the exciter array) is the critical factor that will determine the design requirements and constraints for the other three sub-systems. 

Non-risk remedial action objectives are used to identify remedial actions that will satisfy the current and future non-risk requirements for the site. While risk-based remedial action objectives ensure long-term protection of human health and the environment, non-risk objectives address all other site remedial action requirements and constraints. The non-risk remedial action objectives should cover all non-risk site constraints that will define an... 

Fig. 1. The problem of reactor selection to meet the desired process requirements and constraints.

Blood Gas Analysis Cell. The blood gases enter the mass spectrometer by permeation through a thin Teflon membrane enclosed in the blood gas cell (BGC). The design of the stirred BGC was determined by the following general requirements and constraints ... 

What schedule requirements and constraints do you have Different contracting methods support different schedule requirements. Make sure that you understand the typical time hne for each project delivery method. 

Schedule requirements and constraints (must start and/or must complete dates)... 

Identifying environmental requirements and constraints. Environmental conditions influence performance and functional capacities in humans. They should therefore be measured or estimated in task analyses. Table 80.1 describes common environmental constraints. 

At each level, the context in which the behaviors took place is considered. The context for each level includes the hazards, the safety requirements and constraints, the controls in place to prevent the hazard, and aspects of the environment or situation relevant to understanding the control flaws, including the people involved, their assigned tasks and responsibilities, and any relevant environmental behaviorshaping factors. Following a description of the context, the dysfunctional interactions and failures at that level are described, along with the accident factors (see figure 4.8) that were involved. 

Safety Requirements and Constraints The ACE and mission director must follow the procedures specified and implied by the ROE, the ACE must ensure that pilots... 

This level of the control structure contains more examples of inconsistent mental models and asynchronous evolution. In addition, this control level provides interesting examples of the adaptation over time of specified procedures to accepted practice and of coordination problems. There were multiple controllers with confused and overlapping responsibilities for enforcing different aspects of the safety requirements and constraints (figure 5.8). The overlaps and boundary areas in the controlled processes led to serious coordination problems among those responsible for controlling aircraft in the TAOR. 

Safety Requirements and Constraints The general safety constraint involved in the accident at this level was to prevent misidentification of aircraft by the pilots and any friendly fire that might result. More specific requirements and constraints are shown in figure 5.8. 

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