System design review

System design review (SDR) the hardware SDR immediately follows the preliminary design phase and will encompass a top-level review of the system hardware characteristics such that preliminary design may proceed with confidence. Key hardware characteristics will be reviewed at this stage to ensure that there are no major mismatches between the system requirements and what the hardware is capable of supporting. 

Transport Models. Many mechanistic and mathematical models have been proposed to describe reverse osmosis membranes. Some of these descriptions rely on relatively simple concepts others are far more complex and require sophisticated solution techniques. Models that adequately describe the performance of RO membranes are important to the design of RO processes. Models that predict separation characteristics also minimize the number of experiments that must be performed to describe a particular system. Excellent reviews of membrane transport models and mechanisms are available (9,14,25-29). 

Reviews of concentration polarization have been reported (14,38,39). Because solute wall concentration may not be experimentally measurable, models relating solute and solvent fluxes to hydrodynamic parameters are needed for system design. The Navier-Stokes diffusion—convection equation has been numerically solved to calculate wall concentration, and thus the water flux and permeate quaUty (40). 

Cure Systems of Butyl Rubber and EPDM. Nonhalogenated butyl rubber is a copolymer of isobutjiene with a small percentage of isoprene which provides cross-linking sites. Because the level of unsaturation is low relative to natural mbber or SBR, cure system design generally requites higher levels of fast accelerators such as the dithiocarbamates. Examples of typical butyl mbber cure systems, thein attributes, and principal appHcations have been reviewed (26). Use of conventional and semi-EV techniques can be used in butyl mbber as shown in Table 7 (21). 

Melt crystallization is carried out either with a suspension of crystals or an advanciag front (layer) of soHds, although a more complete categorization of melt crystallization is available (71). FoUowiag is a brief review of processes ia which melt crystallization is used a more complete review, including a worked out case study for system design, is available (69). 

Some approaches to quality management suggest that companies reduce the total number of suppliers for a service or material to just a few high quality entities. This allows the companies to symbi-otically develop relationships. Both parties can benefit greatly by using a system designed to rank preferred tollers. However, do not let the motivation to reduce the number of suppliers inhibit the critical review of potential tollers capable of performing the toll successfully. 

Rigorous design reviews must include the often highly complex resonance behavior of impellers and blading to ensure vibration-free or vibration-tolerant design of these critical turboexpander components. In other words, the manufacturer must perform comprehensive theoretical and experimental studies of the blade oscillations in the rotating system. 

The number of flare headers and individual subheaders connected to them depends upon the type of vapors handled, process temperature conditions, and the available back-up pressure or limitations of the pressure receiving devices specified for the system. This section reviews some of the important design criteria and considerations for the headers and subheaders, which is an integral part of the overall flare system design. 

Designs should be based on knowledge of what the human body (and human nature) will do. Include educated operators in design reviews. The HAZOP methodology for process hazard analysis offers an excellent opportunity to identify design and procedural opportunities for inherently safer systems. After all, the OP in HAZOP stands for operability (COPS, 1992). For example, a safe start-up procedure that requires the operator to walk up and down the stairs three times to manipulate valves in the correct sequence can be made inherently safer by locating the valves so that operator has to walk up the stairs only once during the start-up. 

In one site, the project team installing a DCS (Distributed Control System) carefully developed and tested techniques to make the displays clear for red-green color blind personnel (see discussion in 6.4). The displays were effective and were applauded by the operators. However, in subsequent DCS installation projects at the same site, different project teams made no provision to make displays visible to red-green color blind personnel. This inherently less safe condition was found during a design review at one unit and at the pre-start-up safety review for another unit. 

The standard doesn t require a procedure for Management Review and while it does require procedures for Design Control it does not specify that a Design Review Procedure is required. The phrases consistent with and in accordance with have the same meaning as both imply compatibility and agreement. If you restrict yourself to a literal interpretation of the standard, you need produce no more than 43 documented procedures - possibly less if some aspects do not apply to your business. You can combine several procedures in one document, the size of which depends on the complexity of your business. The more complex the business the greater the number of quality system documents. The more variations in the ways that work is executed, the larger the quality system will need to be. If you have a small business and only one way of carry-... 

At this point in the process, you may find it useful to review the preliminary plan you presented for initial management approval (see Chapter2). That "first take" necessarily lacked the detail you are now able to provide. For example, your initial estimates of time requirements might have predicted 18 months for system design and installation now you reali2e that 24 months will be needed. While the initial plan will require changes, it should have components (organizational, stylistic, narrative) that can be adapted for use in the formal plan. 

A review of these thresholds can help you select the best approach to systems design for your company s needs. Also consider other factors, such as ... 

Changes in process and materials do not trigger MOC review Causes MOC system design gap... 

What Incentives andjor Performance Criteria Apply. Participating in PSM system design may be its own reward however, this may not always be entirely realistic, especially when an assignment falls outside a team member s usual job description. Consider what incentives may apply to the design team s contribution to your company s PSM initiative. These need not necessarily be monetary they maybe incorporated into performance reviews, which should recogruze extra effort. Whatever the method, incentives (and disincentives) need consideration in advance and should be communicated clearly to team members. 

When looking at one-time problems, it is important to consider whether this could have directly led to an undesired consequence, such as an accident or incident or a noncompliance situation, or if there is another level of safeguard. If it is concluded that the problem or weakness could have directly led to an undesired consequence, the system design should be reviewed to find a way in which a safeguard can be provided. Systematic issues require a redesign of the system to remove the potential for the problem. 

It is important, especially when consistency has not been designed or built into the maintenance reporting system, to review the data reported to minimize misinterpretation. Clearly defined equipment boundaries for plant hardware are essential for the generation of relevant data. For example, one classification method may define pumps as only the mechanical portions of the pump, whereas another may include the driver (e.g., the motor) and associated controls. Interviews with operating and maintenance personnel as well as review of the maintenance procedures and documents can provide insight into the... 

Identify potential applications for technology in transportation security with a focus on likely threats derived from threat analyses that drive security system requirements. Review security system developments structured to meet the changing threat environment. Assess government and commercial industry plans designed to address these threats. 

In the next section of this chapter, we will review a variety of instrumentation approaches to the FLIM experiment. In particular, we describe conventional systems as well as those designed to observe variation in a, and systems designed for the collection of multifrequency data. In this context, we will also look at data collection strategies and the subsequent first pass analysis of the acquired... 

The primary donor in Photosystem I P700 is thought to be a special pair of chlorophyll a molecules. Katz and Hindman (18) have reviewed a number of systems designed to mimic the properties of P700 ranging from chlorophyll a in certain solvents under special conditions where dimers form spontaneously (19) to covalently linked chlorophylls (20). Using these models it has been possible to mimic many of the optical, EPR and redox properties of the in vivo P700 entity. 

Phase quadrature is an over-arching concept for all interferometric detection. However, achieving a common-path configuration that locks in a stable quadrature condition puts constraints on possible system designs. This section reviews the several configurations of common-path quadrature that have been demonstrated so far in spinning-disc systems. These are the micro-diffraction class, the adaptive optical class, the phase contrast and the in-line class. At the end of this section, we show that the phase-contrast and in-line classes are conjugate quadratures of each other. 

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