Design for Responsiveness

Assume we want to heat a pot of water on the stove from room temperature to a particular temperature below the boiling point. The time it takes to heat the water depends, in part, on how much heat Qs is contained (stored) in the water when we reach the final temperature TV 

The time for heating also depends on the supply of heat from the burner 

U = heat transfer coefficient A = heat transfer area 

Finally, the time for heating depends on rate of heat loss Qd (dissipation) due to evaporation and convection. If we assume that the supply and dissipation rates remain constant (true only over narrow intervals of water temperature), the time th for heating the pot to the target temperature is 

As we all know, the heating time is reduced when there is little water in the pot, when the target temperature is low, when the burner is hot, and when there is a lid on the pot. Assume now that we took all those measures and managed to overshoot the target temperature. What do we do then We turn off the burner, remove the lid, and probably stir to improve the rate of heat dissipation. The time it takes for the water to settle to the correct temperature is 

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Mojo, S. A. 1996. Designing for responsible disposal. In Biodegradable Polymers and Packaging, C. Chung, D. L. Kaplan, and E. L. Thomas, eds. Technomic Publishing, Lancaster, Pennsylvania. 

Innovative product An innovative product has high margins and uncertain demand. The supply chain for such products should be designed for responsiveness to demand, rather than efficiency. (See functional product.)... 

Hanna, G. (1993) Designing for responsible disposal. Recycle 93, Maack Business Services, Switzerland, Paper 18/2. 

Curved one-factor response surface showing (a) the limitation of a 2 factorial design for modeling second-order effects and (b) the application of a 3 factorial design for modeling second-order effects. 

Four replicate measurements were made at the center of the factorial design, giving responses of 0.334, 0.336, 0.346, and 0.323. Determine if a first-order empirical model is appropriate for this system. Use a 90% confidence interval when accounting for the effect of random error. 

Deodorization can be carried out ki batch, continuous, or semicontkiuous systems. Figure 4 shows a typical design for a semicontkiuous deodorizer. The heated ok is passed through a series of trays under vacuum. Steam is passed through the ok through a steam sparge ki the bottom of the tray. Volatiles are carried through the headspace and condensed. In addition to fatty acids and compounds responsible for odor, some tocopherols and sterols are also distilled kito the condensate. The amount of tocopherols distilled depends on deodorization temperature and vacuum. 

Rheometric Scientific markets several devices designed for characterizing viscoelastic fluids. These instmments measure the response of a Hquid to sinusoidal oscillatory motion to determine dynamic viscosity as well as storage and loss moduH. The Rheometric Scientific line includes a fluids spectrometer (RFS-II), a dynamic spectrometer (RDS-7700 series II), and a mechanical spectrometer (RMS-800). The fluids spectrometer is designed for fairly low viscosity materials. The dynamic spectrometer can be used to test soHds, melts, and Hquids at frequencies from 10 to 500 rad/s and as a function of strain ampHtude and temperature. It is a stripped down version of the extremely versatile mechanical spectrometer, which is both a dynamic viscometer and a dynamic mechanical testing device. The RMS-800 can carry out measurements under rotational shear, oscillatory shear, torsional motion, and tension compression, as well as normal stress measurements. Step strain, creep, and creep recovery modes are also available. It is used on a wide range of materials, including adhesives, pastes, mbber, and plastics. 

The P-lactam antibiotics ate produced by secondary metaboHc reactions that differ from those responsible for the growth and reproduction of the microorganism. In order to enhance antibiotic synthesis, nutrients must be diverted from the primary pathways to the antibiotic biosynthetic sequences. Although most media for the production of penicillins and cephalosporins are similar, they ate individually designed for the specific requkements of the high yielding strains and the fermentation equipment used. 

Ceramic-matrix composites are a class of materials designed for stmctural applications at elevated temperature. The response of the composites to the environment is an extremely important issue. The desired temperature range of use for many of these composites is 0.6 to 0.8 of their processing temperature. Exposure at these temperatures will be for many thousands of hours. Therefore, the composite microstmcture must be stable to both temperature and environment. Relatively few studies have been conducted on the high temperature mechanical properties and thermal and chemical stability of ceramic composite materials. 

The half-pipe jacket is used when high jacket pressures are required. The flow pattern of a liquid heat-transfer fluid can be controlled and designed for effective heat transfer. The dimple jacket offers structural advantages and is the most economical for high jacket pressures. The low volumetric capacity produces a fast response to temperature changes. 

As we ve di,seussed, system design is responsible for much of cavitation. Yet, the maintenanee mechanic is responsible for stopping and preventing eavitation. And certainly, it s the maintenance mechanic who has to deal with the results of cavitation, the constant changing of bearings, meehanical seals, damaged impellers, wear rings and other pump parts. 

Figure 1.16 Designer s responsibility for mechanical failures (designer s share is shaded) (Larsson etal., 1971)...

Components/eharaeteristies in the unaeeeptable design zone are virtually eertain to eause expensive failures unless redesigned to an oeeurrenee level aeeeptable for their failure severity rating (minimum Cpi = 1.33). In the intermediate zone, if aeeeptable design eonformability eannot be aehieved, then speeial eontrol aetion will be required. If speeial aetion is needed then the eomponent/eharaeteristie is eritieal. However, it is the designer s responsibility to ensure that every effort is made to improve the design to eliminate the need for speeial eontrol aetion. 

Does the SAHP designate an individual responsible for authorizing eutting and welding operations in areas not speeifieally designed for sueh proeesses [OSHA Referenee. 252(aX2Xxiii)(B)]... 

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