Frequency infrared drying

Special drying methods, such as superheated steam, solvent, vacuum, infrared radiation, and high frequency dielectric and microwave heating, are occasionally employed when accelerated drying is desired and the species being dried can withstand severe conditions without damage. None of these methods is of significant commercial importance. 

The sparingly water-soluble triethylammonium saltofBi2H122-is readily converted to the highly water-soluble sodium salt. A carefully weighed sample of the triethylammonium salt is treated with an exactly equivalent amount of standardized aqueous sodium hydroxide. The mixture is heated to effect solution and then boiled to expel the free triethylamine until the vapors are no longer basic. Evaporation to dryness then leaves a crystalline hydrate of Na2Bi2Hi2. The anhydrous salt is obtained by drying at 100°/1 n for 24 hours and has characteristic infrared absorption frequencies as a Nujol mull (exclusive of any frequencies coincident with Nujol) at 2470 (s), 1010 (w), 1070 (m), 770 (w), 727 (m),710 (m),and 700 (m) cm. 1... 

The usefulness of infrared spectroscopy of proteins and membranes is increased when spectra of dry films are compared with those taken in deuterium oxide. Exchange of protons for deuterons can affect both the amide I and amide II bands. For randomly coiled proteins in D20 the amide I band is shifted down by about 10 cm."1 but for many proteins D20 does not affect the frequency of the carbonyl stretch of either the ft structure or the a-helix. In addition, upon complete exchange the amide... 

Moisture analyzers include a large variety of designs listed here. The list includes their inaccuracies (1) electrolytic hygrometer (2-5% FS), (2) capacitance (3% FS), (3) impedance (3% FS), (4) piezoelectric (10% AR or 2 ppm by volume), (5) heat of adsorption, (6) infrared (0.5-1% FS), (7) microwave (for a 1-15% moisture range, error is within 0.5%, less if corrected for density), (8) Karl Fischer titrator (0.5-1% FS), (9) drying oven (0.5-1% FS), (10) dipole, (11) cavity ring down, (12) fast neutron (0.2% in solid s density corrected), and (13) radio-frequency absorption (5 ppm). 

An ink must be transformed to a solid from its liquid supply form once on the substrate. This change of state is referred to as an ink drying, and can be physical (absorption or evaporation) or chemical (oxidative or photochemical radiation induced). There are several forms of radiation used to dry ink, including UV, infrared, EB, microwave, and radio frequency. 

The third heat transfer mechanism is radiation, examples of which are infrared and radio frequency dryers. Radiant heaters are often used as predryers, removing much of the moisture from wet fabric prior to entering the actual drying process (Fig. 2.14). Use of predryers minimises finish migration and increases dryer productivity since less water must be removed in the dryer. A more detailed description of drying methods and machines is given by Miles. ... 

Field Effects Drying—Drying with Infrared, Radio-Frequency, and Microwave Methods... 

For catalysts that were simply dried in air at 110°C after impregnation of the alumina with H2PtClfe and Re207, it was concluded that a platinum-rhenium alloy formed on reduction. This conclusion was based on the observation that the presence of platinum accelerated the reduction of oxygen chemisorbed on the rhenium and on results showing that the frequencies of the infrared absorption bands of carbon monoxide adsorbed on platinum and rhenium sites in platinum-rhenium catalysts were different from those found with catalysts containing only platinum or rhenium. However, for catalysts calcined in air at 500°C prior to reduction in hydrogen, it was concluded that the platinum exhibited much less interaction with the rhenium (66,71). 

Figure 14 shows infrared absorption spectra of sol-gel-derived (Bao.2Pbo.8)Ti03 calcined powder for various dispersives in pH. The intensity of the hydrogen bond and the characteristic bond of the organic compound in the dried gel decrease as the pH is increased. Peaks 2 and 3 become sharper with an increase in pH and shift to higher frequencies as the crystalline phase becomes more stable. Figure 15 shows the apparent and relative density for... 

Dostie, M., 1992. Optimization of a drying process using infrared radio frequency and convection heating. In Drying 92f A.S. Muiumdar (Ed.). Elsevier, Amsterdam, the Netherlands, 679pp. 

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