Initiator design

Enhancements to the process may be required due to sub-optimal initial design of the equipment, or to implement new technology, or because an idea for improving the production system has emerged. De-bottlenecking would be an example of an... 

The radiation and temperature dependent mechanical properties of viscoelastic materials (modulus and loss) are of great interest throughout the plastics, polymer, and rubber from initial design to routine production. There are a number of laboratory research instruments are available to determine these properties. All these hardness tests conducted on polymeric materials involve the penetration of the sample under consideration by loaded spheres or other geometric shapes [1]. Most of these tests are to some extent arbitrary because the penetration of an indenter into viscoelastic material increases with time. For example, standard durometer test (the "Shore A") is widely used to measure the static "hardness" or resistance to indentation. However, it does not measure basic material properties, and its results depend on the specimen geometry (it is difficult to make available the identity of the initial position of the devices on cylinder or spherical surfaces while measuring) and test conditions, and some arbitrary time must be selected to compare different materials. 

The way a pilot plant is designed affects its cost, operabiUty, and effectiveness. AH operating ranges may not yet be fully defined at the initial design stage, but a reahstic preliminary range is required before the design is commenced, as is a clear definition of the pilot plant s purpose. 

Prevention of Significant Deterioration. EPA originally issued regulations for Prevention of Significant Deterioration (PSD) in December 1974 to protect clean air areas. Three air quaUty classes were designated Class I to protect pristine areas. Class II to allow moderate development, and Class III to permit more intensive development. Most areas in the United States were initially designated as Class II. Many large national parks and wildlife areas have been classified as Class I. 

Under current regulations, chemicals allowed for use in various European countries (Table 3) are either fully Hcensed for aquacultural use (oxytetracycline, oxolinic acid) or can be prescribed by veterinarians if they are Hcensed for use on other food animals (14—16). In addition, previously unHcensed chemicals that are appHed to the water (topicals) may now be used under a grandfather clause if no one questions their safety. The question of whether a chemical is a medicine or a pesticide has also been addressed. Eor example, dichlorvos (Nuvan 500 EC) was initially designated as a pesticide in the United Kingdom, but was later categorized as a medicine. A similar product, trichlorfon (Masoten), was treated the same way in the United States. 

This case study concerns the initial design and redesign of a security cover assembly for a solenoid. The analysis only focuses on those critical aspects of the assembly of the product that must be addressed to meet the requirement that the electronics inside the unit are sealed from the outside environment. An FMEA Severity Rating (S) for the assembly was determined as S = 5, a warranty return if failure is experienced. 

The initial design of the cover assembly as shown in Figure 2.35 uses an O-ring to seal the electronics against any contamination. Concerns were raised about three mains aspects of the assembly, these being ... 

Comparing this value with the initial design s high potential eost of failure, it is evident that a major design fault in the eover has been eliminated although the assembly proeess must remain within speeial eontrol. Subsequently, the redesign solution was ehosen for further design development. 

The initial design is analysed using CA at a component level for their combined ability to achieve the important customer requirement, this being the tolerance of 0.2 mm for the plunger displacement. Only those characteristics involved in the tolerance stack are analysed. The worst case tolerance stack model is used as directed by the customer. This model assumes that each component tolerance is at its maximum or minimum limit and that the sum of these equals the assembly tolerance, given by equation 2.16 (see Chapter 3 for a detailed discussion on tolerance stack models) ... 

Figure 2.42 Variability risks analysis for the solenoid end assembly initial design...

For studies or initial design it is good to have quick estimates of pump NPSH. Evans discusses the general formula... 

The best and most effective time to provide for reliability is in the initial design. The importance of initial design is illustrated by a study" undertaken by Sohio at their Toledo refinery. Their first listed major finding from the study was as follows ... 

Since the process engineer plays a large role in initial design, what are some things he/she can do to help assure reliability ... 

Solution After thorough analysis, including heat and material balances and hydraulic calculations, the initial design flaws were corrected including ... 

If the above procedure is executed, the initial design of any magnetic component should take less than 30 minutes. Please refer to the end of Appendix D for the listing of the core manufacturer s websites where the needed information can be downloaded. 

The reader should refer to the chapter on pumps for more detailed calculation methods and for a description of common pumping equipment and pumping applications. The simple relationships provided here are useful in obtaining initial design specifications information in sizing a pump for an application. 

Process and Layout Requirements The key to a successful enclosure installation is to consider all process and layout requirements during the initial design stage. When planning an enclosure for a metallurgical furnace, the following questions should be asked ... 

Relief valves are often seen to be undersized for the required relieving rate, due either to poor initial design or changes in the process conditions which occurred during design. The most common system problem is that the relief valve was adequately sized for blocked discharge but not sized for the flowrate that could occur as a result of a failure in the open position of an upstream control valve (i.e., gas blowby). See Chapter 13. 

The engineer providing the initial design of major facilities is faced with the decision of providing a motor control center building or indi id-ual (usually rack-mounted) motor starters and corresponding branch circuit protection devices. For installations using only several motors it fre-... 

Risk-based decision making and risk-based corrective action arc decision making processes for assessing and responding to a health hazard. The processes take into account effects on human healdi and the enviroiunent, inasmuch as chemical releases vaiy greatly in terms of complexity, physical and chemical characteristics, and in the risk that they may pose. Risk-based corrective action (RBCA) was initially designed by the American Society for Testing and Materials (ASTM) to assess petroleum releases, but tlie process may be tailored for use with any hazard. 

Interestingly, many companies use standard checklists for controlling die development of a project from initial design dirougli plmit shutdown. It serves a form for approval by various staff and management functions before a new or retrofit project can mo e ahead. 

Capillary viscometers are simple and inexpensive. They are normally constructed from glass and resemble a U-tube with a capillary section between two bulbs. The initial design originated with Ostwald and is shown as part A in Figure 3.2-1. The Cannon-Fenske type, a popular modification of the Ostwald design that moves the bulbs into the same vertical axis, is shown as part B in Figure 3.2-1. 

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