Finger surface

A reasonably dust-free cabinet stocked with a variety of standard wall tubing, heavy-walled capillary tubing, and rod A ring stand and clamps with woven-glass-covered fingers Surface-mix bench burner for large items... 

Fig. 9 FT-IR image of a finger surface acquired using the diamond ATR accessory. An extracted spectrum from the area indicated by the arrow is shown on the right...

Figure 10.17 ATR-FT-IR image of the finger surface. The image on the left represents the protein distribution while the image on the right represents the ibuprofen distribution.

Heating the sample with a miCToburner or a sand bath to just below the melting point of the solid causes sublimation to occur. Vapors condense on the cold-finger surface, whereas any less volatile residue will remain at the bottom of the flask. Apparatus for sublimation of small quantities are now commercially available (Fig. 5.52). Two examples of simple, inexpensive apparatus suitable for sublimation of small quantities of material in the microscale organic laboratory are shown in Figure 5.53. 

A drop of surfactant solution will, under certain conditions, undergo a fingering instability as it spreads on a surface [27, 28]. This instability is attributed to the Marongoni effect (Section IV-2D) where the process is driven by surface tension gradients. Pesach and Marmur have shown that Marongoni flow is also responsible for enhanced spreading... 

Stoppers. Those fitted with 514,519, and 524 cones are useful sizes. Stoppers with flat heads are to be preferred, since they may be stood on end when not in pse, thus avoiding contamination of the ground surface. An additional refinement is the provision of a finger grip as in Fig. II, 56,1. 

Pressure-Sensitive Adhesives. A pressure-sensitive adhesive, a material which adheres with no more than appHed finger pressure, is aggressively and permanently tacky. It requkes no activation other than the finger pressure, exerts a strong holding force, and should be removeable from a smooth surface without leaving a residue. 

Fig. 4.10. The two main types of dear-ice machine. In the top one, the ice grows on the outside of a set of aluminium cold fingers. In the bottom one, the cubes grow in aluminium troys. Cubes ore removed when they ore big enough by stopping the flow of refrigerant and heating the aluminium electrically. This melts the surface of the ice so that it con fall away from the metal (remember that the easiest way to take the wrapper off on ice lolly is to worm the outside with your hands for a minutel)...

Solvent-borne adhesives. Although the NR polymer is inherently tacky, tack-ifying resins are generally added to improve bonding to polar surfaces. Because the solids content in these adhesives is lower than 35 wt%, they are not suitable for gap filling. The quick-grab (cements) adhesives are particular because they contain about 65 wt% rubber, and set within a few seconds under finger pressure. 

Tack slight stickiness of the surface of a film of paint, varnish or lacquer, apparent when the film is pressed with the finger. 

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