Design with cracks

Figure 5.13 Calomel reference electrodes (a, b) commercial designs with cracked-glass and fiber junctions, respectively (c) home-made design with cracked-glass junction on the bottom of left tube.

Installation for Ultrasonic Testing AKV-S is designed for testing of diesel motors pistons. Particularly, this device identifies the areas with cracks and lowered adhesion on interfacial boundary between niresist ring and base material. 

In 1974, 28 people died in an explosion resulting from a large release of cyclohexane in Flixborough, U.K. The source of the hydrocarbon release was a failed expansion joint in a section of 20-inch (508-mm) diameter pipe. Investigation revealed the pipe had been designed with little technical input as a temporary bypass for a reactor that had been removed after it cracked. 

Design of layered composites with crack bifurcation in compressed layers... 

While originally designed for cracking the overhead stream from vacuum distillation units, known as vacuum gas oil (4), most FCC units currently operate with some higher boiling vacuum distillation bottoms (Resid) in the feed. Table 5.1 illustrates the difficult challenges faced by refiners, process licensors and FCC catalysts producers the resid feeds are heavier (lower API gravity), contain many more metals like Ni and V as well as more polyaromatic hydrocarbons prone to form coke on the catalysts (Conradson Carbon Residue, or CCR). 

Several attempts were made to prepare pillared smectites with sufficient hydrothermal stability for use as active components in catalysts for catalytic cracking of heavy oil fractions. Although improvements were made, none of the attempts resulted in pillared materials stable enough to withstand the hydrothermal conditions found in the regenerator of a commercial FCC. One type of materials studied, i.e. alumina-montmorillonites, may be attractive alternatives to the active matrices, often alumina, currently used in FCC-catalysts designed for cracking of heavy oils. The alumina-montmorillonites can, perhaps, not be considered to be bona fide pillared smectites as they have considerably larger pores and a wider pore-size distribution than what is characteristic for pillared smectites. 

Fig. 4. Experimental determination (i) of in case of linear elastic material behaviour (ii) of K ir by correction with the radius of the plastic zone, present at the vicinity of the crack tip designs the crack length used for...

Acrylic coatings designed for their crack-bridging capability are based on soft polymers which have a low glass transition temperature (as low as -45°C). Such coatings move with cracks in a wall over a wide range of temperatures and prevent ingress of bulk water and penetration by carbon dioxide and chloride ions. 

Fig. 11. Thennofor catalytic cracking (TCC) unit. Early design with bucket elevators. (Courtesy of Socony-Vacuum Oil Company, Inc.)...

Initial investment for horizontal tube evaporators is low, but heat transfer rates may also be relatively low. They are well suited for non-scaling, low viscosity liquids. For several scaling liquids, scale can sometimes be removed from bent-tube designs by cracking it off periodically by shockcooling with cold water or, removable bundles can be used to confine the scale to that part of the heat transfer surface which is readily accessible. 

OB of nonfragmenting explosives is conducted in burning trays, which are designed without cracks or angular comers to prevent the buildup of explosive residues. The depth of explosive material in a tray may not exceed 3 inches, and the net explosive weight of materials in a tray may not exceed 1,000 lb. The distance between the trays for explosive devices is determined by hazards analysis, but, in the absence of such analysis, trays are placed parallel to one another and separated by at least 150 ft. These distances may vary for OB of bare explosives or explosives-contaminated soils. When wet explosives are being burned, trays may be lined with nonexplosive combustible materials, such as scrap wood, to ensure complete combustion. An OB tray may not be inspected until 12 hours after the conclusion of the bum, and a tray may not be reused until 24 hours after the conclusion of the bum or until all ash and residues have been removed from the tray. 

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