Drums structure

Figure 1. Schematic representation of the drum structure of [PhSn(0)02CCgHii]g. (Reproduced from Ref. 3.

Other than the chloro derivative, 2, the drum and ladder compounds are prepared in high yield, > 70%. All are soluble in organic solvents and show characteristic infrared spectra. The drum compounds and A exhibit a symmetrical doublet for the carboxylate stretching frequency, Vqqq, centered near 1550 cm 1 and a single Sn-0 stretch, v Q, near 600 cm-1. In contrast, the open-drum structures, 2 and 3, show an unsymmetrical vcoo doublet in the same region as that for the drums and the presence of two Sn-0 stretches near 600 cm. ... 

The ladder structure is also a common structural motif for higher nuclearity tin carboxylate clusters and can be seen as an unrolled drum structure, and this structural type (120), seen in such complexes as [(Bu Sn(0)02CPh)2(Bu SnC102CPh)2]2 and [Bu2Sn0(R)]20 2 (R = C(0)CH2SC(0)N(CH2CH2)20) is commonly found. The latter compound was more active than cwplatin against a number of cancer cell lines. 

Not until X-ray diffraction studies were performed was their structure finally clarified. Now, two types of hexanuclear organotin oxo-carboxylates are known -hexamers of composition [RSnO(OOCR )]6, which have a hexagonal prismatic cage structure, 165, (or drum structure) and ladder type compounds, 166, of composition [ RSnO(OOCR ) 2 RSn(OOCR )2X ] (X = R COO or Cl) both contain Sn202 aggregates. The compounds have been reviewed (510). 

The forest has largely reclaimed the Amoco Refinery in Destre-han, Louisiana. A large sugar maple sprouts from a long since forgotten control room. If one didn t know, the delayed coker drum structure might be mistaken for a ruined temple. Brick chimney stacks rise defiantly above the feathery tops of the cypress trees. 

Rotary Drum Filters The rotaiy drum filter is the most widely used of the continuous filters. There are many design variations, including operation as either a pressure filter or a vacuum filter. The major difference between designs is in the technique for cake discharge, to be discussed later. All the alternatives are characterized by a horizontal-axis drum covered on the cylindrical portion by filter medium over a grid support structure to allow drainage to manifolds. Basic materials of construc tion may be metals or plastics. Sizes (in terms of filter areas) range from 0.37 to 186 m (4 to 2000 ft ). 

Response of Equipment The response of equipment to blast is usually a combination of two effects one is the displacement of the equipment as a single entity and the other is the faihire of the equipment itself. The displacement of the equipment is an important consideration for small, unsecured items—e.g., empty drums, gas cyhnders, empty containers. Most damage resmts from the faihire in part or totally of the equipment or containing structure itself. 

The second failure mode to consider is fatigue. The drum will revolve about once every second, and each part of the shaft surface will go alternately into tension and compression. The maximum fatigue stress range (of 2 x 56 = 112 MPa) is, however, only a quarter of the fatigue limit for structural steel (Fig. 28.5) and the shaft should therefore last indefinitely. But what about the welds There are in fact a number of reasons for expecting them to have fatigue properties that are poorer than those of the parent steel (see Table 28.1). 

Fig. 28.5. Fatigue data for a typical structural steel in dry air. Note that, if the fatigue stress range is less than 440 MPa (the fatigue limit] the component should last indefinitely. The data relate to a fatigue stress cycle with a zero mean stress, which is what we have in the case of our tail drum.

High molecular weight HDPE (HMW-HDPE) is used for blown film and for demanding moulding and structural uses. Examples are blow moulded drums for packing dangerous chemicals and pressure piping. 

From the viewpoint of accommodation to the filter-supporting structure, some cloths cannot be used, even though the filtering characteristics are excellent. For rotary drum filters, for example, the cloth is pressed onto the drum by the caulking method, which uses cords that pass over the drum. In this case, the closely woven cloths manufactured from monofilament polyethylene or polypropylene fiber are less desirable than more flexible cloths of polyfilament fibers or staple cloths. 

Preferably, the HjS flare system should consist of a segregated header and separate line routed up the side of a conventional elevated flare stack, sharing the same structure, pilots and igniters. However, the HjS header may be tied into the regular flare seal drum if there are special mechanical design problems associated with the separate stack e.g., in the case of a flare which is to be dismantled for overhaul. Flare elevation must be sufficient to meet atmospheric pollution and ground level concentration requirements for the sulfur dioxide produced. 

This specification covers the minimum requirements for the process, mechanical and structural design, materials, fabrication, shop inspection testing and supply for a flare system. The knock-out drum will be by N P Refinery. 

Each of the three process lines is supported within a structural steel framework that is 20 m tall. Each line contains a number of vessels (reactors, flash drums, separa-... 

Alpha quartz (aSi02) is found throughout the boiler and post-boiler sections. It is a very hard, adherent scale, found in the mud drum, on boiler tubes, and on turbine blades as a hexagonal crystal structure. 

As outlined elsewhere (A), we have employed a variation of the original reaction hy Lambourne (3) in exploring condensation products leading to the drum composition as well as to a mixed oxycarboxylate-tricarboxylate formulation, [ (R Sn(0)02CR) 2R Sn CR) 3 ] 2. The latter was identified as having an unfolded drum or ladder structure (A). 

Our investigation using 119Sn NMR establishes the retention of the drum and ladder structures in solution and shows their interconversion according to Equation 3. 

Structural Details. For 1, the hexameric "drum" has idealized Sg molecular symmetry. The geometry of the stannoxane framework of the molecule consists of six-membered rings in a chair conformation. 

Phosphinic Acid Reactions. Reaction of n-butylstannoic acid with diphenylphosphate instead of a carboxylic acid also results in the formation of a drum composition [ n-BuSn(0) 02P (OPh)2] g (Chandrasekhar, V. Holmes, J. M. Day, R. 0. Holmes, R. R., unpublished work). However, when diphenylphosphinic acid is reacted with n-butylstannoic acid under reflux in toluene, a new structural form of tin is obtained (7 ). The reaction proceeds according to Equation 4 giving the stable oxide composition in 90% yield, mp 198-208°C dec. 

Figure 7 Suggested structural representation just prior to closure to yield the drum. (Reproduced from Ref. 5- Copyright 198 American Chemical Society.)...

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