Tube Selection

The volatile liquid (boiling point, 22° melting point, —10°) must now be distilled from the U tube and sealed in a glass tube. Select a strong tube of suitable diameter of soft glass, seal one end, and blow it out to rounded form like a test tube. At a height of the tube such that the volume below will be about twice that of the liquid to be preserved, soften the tube and draw it to a constriction of such diameter that the smallest tubing... 

Fuel oil of 18,500 Btu/lb is fired with 13% excess air at 80°F. Flue gas leaves at 410°F. A simplified cross section of the boiler is shown. Heat and material balances are summarized. Tube selections and arrangements for the five heat transfer zones also are summarized. The term Ag is the total internal cross section of the tubes in parallel. (Steam Its Generation and Use, 14.2, Babcock and Wilcox, Barberton, OH, 1972). (a) Cross section of the generator (b) Heat balance ... 

AR ratio of area of fin tube to exterior area of 1-in-OD bare tube (select from Table 5.3 or vendor data)... 

Pressure drop from the length and diameter of the tubes selected. 

These equations can be used to point out the direct proportionality between residence time and the inside diameter of the tube selected. Thus, heat transfers are adjusted to the requisite level by adjusting the number of tubes and their length. 

Attention should be given to HPLC and collection tubing selection as well Tygon tubing that can leach phthalates should not be used in HPLC and fraction-collection equipment. 

Since this may easily clog the connecting tubes, the tubes selected are as wide as possible. On cleaning the tubes with water, this reacts with the phosphonium iodide with the evolution of phosphine, a gas with a garlic-like odour, and which in this case is not spontaneously inflammable. The phosphonium iodide decomposes with water into its components, in accordance with this equation ... 

Lodding and Hammel (28) system incorporated a DTA, a TCD, and gas absorption tubes. The absorption tubes selectively removed certain gaseous products from the DTA furnace effluent gases. Likewise, Wend]andt (32) employed a DTA, TCD, and glass sample bulb manifold. Gaseous products were collected in glass bulbs, which are later analyzed by a mass spectrometer. 

This is a very abridged list. For specific information the reader is advised to consult the catalogs supplied by various manufacturers of pumping tubes. The British company Watson-Marlow has issued a highly recommendable and very detailed Tubing Selection Guide. 

Selective corrosion caused by differences in concentration can be reduced by homogenizing heat treatment or by laying one weld pass over the edges of sheets and tubes. Selective corrosion can be caused by segregation on the face of a heat exchanger tube in boiling highly concentrated nitric acid. 

Phage Display Test-tube selection technique that genetically fuses a protein to the outer-coat protein of a virus that infects bacteria, resulting in display of the fused protein on the outside of the virus. This allows screening of vast numbers of variants of the protein, each encoded by its corresponding DNA sequence. 

Krupke et al. (2003) have shown that the bulk separation of various CNT types could be carried out using alternating current dielectrophoresis. It was established that, when submitted to an electric field, the SWNTs have an induced dipole moment which can be used to move these tubes selectively. Of course, the bundles must be separated previously in individual tubes using an ultrasonication treatment of the nanotubes with surfactants such as the SDS (sodium dodecyl sulfate). The dielectrophoresis is then applied to this solution. The metallic tubes are deposited onto the electrodes, while the semiconducting ones remain in suspension. 

SM Heat Shrink Tubing Selection Guide. [Online]. Available at http //www.3m.com/market/ electrical/elpd/oem/pdf/heat shrink tubing guide.pdf. Accessed 29 Sept. 2004. 

Filter Tube Selection Cotton filter tubes are recommended for moderately acid and alkaline solutions in the pH range of 3 to 11. Polypropylene, Dynel and porous carbon filter tubes are recommended for concentrated acid and alkaline solutions and for all fluoborate solutions over the entire pH range of 0 to 14. Polypropylene filter tubes are also recommended for electropolishing solutions, as well as certain other highly corrosive solutions. Porous stone filter tubes are recommended for concentrated acid solutions. Acetate filter tubes are recommended for water. Sethco filter tubes are available in densities to filter out particles from 150 down to 1 micron. 

Experimental tests were carried out with irregular glass particles in order to compare both calibration techniques. The orifice tube selected was a 140 jum tube which was calibrated with a 20 jam nominal size latex (Coulter Electronics Ltd.) using the so called "half count method". For the mass calibration technique, a sieve fraction of the material under test, in the range of 37 44 tni, was used and a suspension of known concentration (4 8xl0 g/ / cm ) was carefully prepared. The density of the glass particles (Schott Duran 50) was measured to be 2.23 g/cm. ... 

Table 2.16 Thermal desorption tube selection by regulated method (Supelco, 2013).

Sigma-Aldrich (2014) Thermal Desorption Tube Selection Guide, http //www.sigmaaldrich.com/analytical-chromatography/air-monitoringAearning-center/td-tube-selectorhtml (accessed 9 May 2014). 

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