Section Design

We will now consider the special problems in tall tower design which are not described in the ASME Code for Unfired Pressure Vessels. As discussed previously, circumferential stresses control the design of cylindrical vessels if external loads are of small magnitude. In tall vertical vessels, four major factors (wind load, seismic loads, dead weight and vibration) may contribute to axial stresses — in addition to axial stress produced by the operating pressure or vacuum of the vessel. 

Wind loads become a special problem if the vessel is located in hurricane areas such as the U.S. Gulf Coast. Winds apply force which causes the tall vertical vessel to be loaded as a vertical cantilever beam that is fixed at its base. 

The bending stress induced by the cantilever beam action is zero at the top of the tower and a maximum at the base. The bending stress produces a compressive axial stress on the downwind side of the column and a corresponding tensile stress on the upwind side. Thus, regardless of whether a taU vertical tower is operated under vacuum or under internal pressure, there will be an increase of the axial stresses on one side and a subtraction on the opposite side. When this combination of axial stresses equals or exceeds the combined circumferential stress, the axial stresses, rather than the circumferential stresses, will control the thickness requirement of the shell. 

Another environmental factor that must be considered in the design of tall towers is seismic stress produced by earthquakes. In areas where earthquakes have never been a problem in the past, there is no need to consider such stresses. In other areas such as California — and, in fact, in the entire perimeter of land bordering the Pacific Ocean — earthquakes are a serious consideration. Earthquakes have also caused serious damage in isolated interior areas of the United States and in other countries as well. 

---

During 1974—1985, about 200 sulfur—asphalt roads were constmcted worldwide, half of which were ia the United States. AH U.S. SEA experimental sections designed and constmcted according to standard practices usiag standard materials are performing as well as the control sections of conventional asphalt ia these experimental projects (49). 

Modify the cross-sectional design (Fig. 6-35) the slot is thus farther away from the influence of feed-stream velocity. 

Uniform wall thickness Wall requirements are usually governed by the load, the support needs for other components, attachment bosses, and other protruding sections. Designing a product to meet all these requirements while still producing a reasonably uniform wall will greatly benefit its durability. A uniform wall thickness will minimize stresses, differences in shrinkage, possible void formation, and sinks on the surface it also usually contributes to material saving and economy in production. 

Because of the difficulties of presses with HIPS cited earlier, it is usual to transfer the syrup to a suspension reactor containing water and a suspending agent for the completion of polymerization. Design problems for suspension reactors will be discussed in the next section. Design problems for HIPS prepoly batch-mass reactors are analogous to HIPS continuous reactors as discussed in Section 2.3. 

Examples of the protection of alkynes, carboxylic acids, alcohols, phenols, aldehydes, amides, amines, esters, ketones, and alkenes are also indexed on p. xvii. Section (designated with an A 15A, 30A, etc.) with protecting group reactions are located at the end of pertinent chapters. 

Figu re 34. Tidd boiler enclosure with scaled section designated. (From Glicksman and Farrell, 1995.)... 

This book is based on that symposium. It is divided into five sections, designed to capture a representative segment of the latest research on fire and polymers. The book also includes some key contributions not presented at the symposium, all edited and organized for this book. The contributors are major figures in fire research, drawn from not only the United States but also Europe and Israel. 

Figure 6.23 Schematic for the position of the barrier flight via the width of the solids channel [W,) and the depths of the solids and melt channels a) a barrier section design with a continuously decreasing /V b) constant-width solids channel, and c) a hybrid design. The designs all utilize a constant lead length for the primary flight...

Read excerpts 15A and 15B. While reading them, think about the difference(s) in section designations (Abstract and Project Summary) and funding agency expectations and answer the following questions ... 

The Statistical Abstract of the United States is published annually by the U.S. Census Bureau, which groups all the economic activities in the United States into 11 divisions by the Standard Industrial Classification (SIC). The manufacturing division is divided into 20 sections designated by two-digit numbers. The manufacturers that involve chemistry intensively are listed in table 9.1, by two 2-digit numbers, such as 20 Food, 28 Chemicals, and 29 Petroleum Refining. The table lists the number of establishments, the number of employees and value of shipment in 1996. The SIC 28,... 

The finite solution volume model for solid-diffusion control (Patterson s model) will be used (eq. (4.52)). Following the procedure presented in the section Design of a batch reactor system for adsorption and ion exchange (eqs. (4.119)-(4.125)), we obtain the results shown in Table 4.23. 

Size Measurement. After the fractions were filtered, the millipore filters were sectioned to provide separate portions for chemical analysis and for size distribution measurements. One-eighth or one-fourth was set aside in reserve. The section designated for optical microscopy was transferred to a microscope slide and placed in a covered petri dish with a few drops of acetone. The acetone vapor is absorbed by the millipore and renders the filter transparent. 

Reactions are listed by section followed by number equations, by section followed by letter. In the rate constant subscripts, the section designation is omitted for brevity. 

Jeon, N.L., Chiu, D.T., Wargo, C.J., Wu, H.K., Choi, I.S., Anderson, J.R., White-sides, G.M., Microfluidics section Design and fabrication of integrated passive valves and pumps for flexible polymer 3-dimensional microfluidic systems. Biomed. Microdevices 2002, 4(2), 117-121. 

Cross- sectional Design that simultaneously ascertains exposures and outcomes Appropriate for exploring research questions as a first attempt or to generate hypotheses for analytic study designs Can be completed in a relatively short period of time, often at reduced cost Useful initial approach for evaluating human health risks Disease prevalence only Cannot assess causality or the temporal relation between exposure and health outcome Residual confounding may threaten internal validity... 

The pyrolysis furnace effluent is processed for heat and product recovery in an efficient, low-cost recovery section. The recovery section design can be optimized for specific applications and/or selected based on operating company preferences. Flow schemes based on demethanizer first, deethanizer first and depropanizer first configurations are available for particular applications. Shown above is the depropanizer first scheme, which is primarily applicable to liquid crackers. 

McGhee, R.J. and Beasley, W.D. (1973) Low-speed aerod3mamic characteristics of a 17-percent thick airfoil section designed for general aviation applications. NASA TN D-7428. 

This additional material is intended to bring to the readers attention the recent major developments. For easy identification, the following comments are marked by the same section designations to which they pertain in the text of the chapter. 

No two tickets from the same concert hall can have the same set of section designation, row number, seat number, and date. 

---