Solid compressive pressure technique

The terminology of L-B films originates from the names of two scientists who invented the technique of film preparation, which transfers the monolayer or multilayers from the water-air interface onto a solid substrate. The key of the L-B technique is to use the amphiphih molecule insoluble in water, with one end hydrophilic and the other hydrophobic. When a drop of a dilute solution containing the amphiphilic molecules is spread on the water-air interface, the hydrophilic end of the amphiphile is preferentially immersed in the water and the hydrophobic end remains in the air. After the evaporation of solvent, the solution leaves a monolayer of amphiphilic molecules in the form of two-dimensional gas due to relatively large spacing between the molecules (see Fig. 15 (a)). At this stage, a barrier moves and compresses the molecules on the water-air interface, and as a result the intermolecular distance decreases and the surface pressure increases. As the compression from the barrier proceeds, two successive phase transitions of the monolayer can be observed. First a transition from the gas" to the liquid state. 

Cook (Ref 2) devotes Chapter 9 to a discussion of compressive elastic props of solids under expl attack. Modern applications of expls involve the compressibility of solids under extremely high pressures. Walsh et al (Ref 1) reported the equations of state of 27 metals under shock compression. Schall Thomer (Ref 3) measured the shock compressibility of Mg-Al alloy, Lucite polyethylene by flash radiographic techniques... 

If you find that the holes in your preholed stopper are the wrong size or in the wrong location, you can take a solid stopper and custom drill holes which meet your specific requirements. There are several techniques for drilling holes in stoppers, but regardless of the technique used, always start with a solid stopper. Because rubber distorts with pressure, it is more difficult to alter a holed stopper than to drill a new hole. In addition, because elastomers distort and compress, drill hole(s) the same size (rather than slightly smaller) as the tubing you wish to insert. This practice will allow easier insertion of the tube into the hole, yet will still provide a satisfactory leakproof seal. When the stopper is placed into its final location, compression from the container neck will further improve the seal. 

The compression of a solid to transparency is really not new. A standard technique in infrared spectroscopy is the use of mulls made of the heavier alkali halides. These materials are squeezed transparent at relatively low pressures. However, when these low pressures are used, evacuation of the sample is essential. In our work, evacuation is not necessary. A reasonable review of the alkali halide work is given by Ford, Wilkinson, and Price (4). 

A final technique presented for the continuous production of solid dosage forms is extrusion/ spheronization—a technique producing spherical agglomerates of very uniform size. The process is based on low-pressure extrusion and shaping the moist, plastic extrudate into spheres in a spheronizer. These spheres (pellets) are, in most cases, coated after drying and filled into hard gelatin capsules or compressed into... 

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