Indented joining

A column involving the same principle can be made from two reflux condensers. The lower outlet of the outer jacket of the condenser connected to the flask is closed, and the jacket is filled to about two-thirds its height with methyl alcohol. A few small pieces of pumice are introduced to prevent bumping of the alcohol. The upper outlet of this jacket is joined to a second condenser to prevent loss of the methanol vapors. The inner tube of the fractionating column is filled with glass beads which are held in place by indentations made in the lower part of the tube. The outlet of this tube is connected to the U-tube immersed in the freezing mixture. 

For simple distillations a Claisen flask is often used. This flask is, essentially, a round-bottomed flask to the neck of which is joined another neck carrying a side arm. This second neck is sometimes extended so as to form a Vigreux column [a glass tube in which have been made a number of pairs of indentations which almost touch each other and which slope slightly downwards. The pairs of indentations are arranged to form a spiral of glass inside the tube]. 

Notice that a table alias n is used to refer to the table nci h23. This shorthand notation will make it easier to express complex SQL when more and more table joins are used. This statement is spread over several lines with indentation in order to locate and modify SQL clauses more easily. 

Fig. 5.20 Pores in SiC pipe and a disk joined to it by spark plasma sintering (SPS) a pores in the pipe and the interface to pore free the disk is seen, b indent by nano indentation and cracks emanation from the corners. Stern et al. (unpublished). Courtesy of Prof A. Stern...

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