Site Preparation and Structures

Once the plant location area and plot plans have been chosen, as explained in Chaps. 5 and 7, the specific site must be selected and developed for installation of structures. Preliminary exploration of the subsurface conditions should be done prior to purchase of a piece of land, since foundation construction may be abnormally high if the bearing load of the underground strata is poor, even though the surface conditions appear satisfactory. Topographical maps of the site to establish plant grades and excavation, together with transportation facility locations, frost-line, and water-table information, are other important site data required. Some detailed aspects of these factors will be presented next. 

Soil Testing. The prime purpose of soil testing is to determine the load-bearing characteristics of subsurface soil. Representative test borings at different locations in the plant site and at varying strata are made to obtain information on many of the following soil and subsurface properties covered by ASTM standard tests  

Capillarity—measures rate of rise and height of water rise against gravitational forces 

Compressibility—measures volume reduction under load 

Elasticity—measures shape recovery after release of applied load 

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CsPuF6 was prepared and verified to be isostructural with corresponding compounds of uranium and neptunium. Its decomposition was studied in an inert gas atmosphere and in vacuum. Its spectrum has been measured in the region 400-2000 nm. The energy level structure of Pu5+ in the trigonally distorted octahedral CsPuF6 site was computed from a predictive model and compared with the observed spectrum. 

Mono-dispersed silicalite and ZSM-5 type zeolite nanocrystals with a diameter of 80-120 nm were successfully prepared in a surfactant-oil-water solution. The ionicity of the surfactants used in the preparation affected the crystallinity and structure of the silicalite crystals, and silicalite nanocrystals could he obtained when using a nonionic sur ctant. By adding an A1 source into the synthetic solution, ZSM-5 type zeolite nanocrystals with strong acid sites could be obtained. 

Kim and Somorjai have associated the different tacticity of the polymer with the variation of adsorption sites for the two systems as titrated by mesitylene TPD experiments. As discussed above, the TiCl >,/Au system shows just one mesitylene desorption peak which was associated with desorption from low coordinated sites, while the TiCl c/MgClx exhibits two peaks assigned to regular and low coordinated sites, respectively [23]. Based on this coincidence, Kim and Somorjai claim that isotactic polymer is produced at the low-coordinated site while atactic polymer is produced at the regular surface site. One has to bear in mind, however, that a variety of assumptions enter this interpretation, which may or may not be vahd. Nonetheless it is an interesting and important observation which should be confirmed by further experiments, e.g., structural investigations of the activated catalyst. From these experiments it is clear that the degree of tacticity depends on catalyst preparation and most probably on the surface structure of the catalyst however, the atomistic correlation between structure and tacticity remains to be clarified. 

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