Applications of drying methods

Accidents have occurred with almost every method in the past drying in the sunshine, with infra-red rays, in warm air and even with hot water. To minimize accident it is quite important to select the drying method so that it is suitable for the articles to be dried. It is also important to always keep the drier clean. The dried compositions or pieces must be treated with great care, especially when they are removed from the drier. 

In general they must be removed after they have completely cooled to room temperature and it sometimes takes a long time, at least one day. Naturally this does not fit the busy work pattern in an ordinary firework factory, but it is quite dangerous if it is not observed in practice. 

Shaped compositions which contain an inflammable solvent must be thoroughly exposed to the air in a large room to vaporize the solvent as much as possible before transferring it to the drier. 

Compositions which are used for fireworks are mixtures of various components and all the oxidizers dissolve in water. These compositions therefore are easily damaged by moisture. Sometimes this is useful for temporarily keeping a composition in a safe state, as in the wet process for example,sometimes however this can lead to a misfire. 

So many kinds of composition are used for fireworks that a particular kind of operation may be required for each type. This is quite complicated and troublesome, but important. 

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Moisture content is of concern in dry flavorings (e.g., dry whole spices and encapsulated flavors). Since flavorings are volatile, one has to be careful in the application of drying methods. Several methods are available for this purpose [10]. 

Owing to the fact that organic substances have to be separated from a complex sample, transferred to the mass spectrometer target and desorbed, it seems impossible so far to analyse cross-linked binding media from artwork (e.g. dried oil, aged proteins, cross-linked synthetic polymers). Application of classical methods of sample treatment for... 

The whole procedure normally takes about 1 hr. The acid is then evaporated, and the dry matter can be analyzed. This method can be applied to cellulose from wood, as a-cellulose or pulp, or to other celluloses (e.g., cotton) as well as to cellulosic materials with higher amounts of other polysaccharides (e.g., holocellulose). The chromatograms of the hydrolysates of a-cellulose from beechwood and of holocellulose from sprucewood (Figure 6) are examples of the application of this method. Compared with sulfuric acid hydrolysis, the total sugar yield from the spruce holocellulose is higher after the hydrolysis with concentrated TFA (Table II). Regarding the individual sugars, it can be seen that the... 

Lindberg SE, Owens JG, Stratton WJ. 1994. Application of throughfall methods to estimate dry deposition of mercury. In Watras CJ, Huckabee JW, eds. Mercury pollution integration and synthesis. Boca Raton, Florida Lewis Publishers, 261-271. 

The purpose of dry separation is the removal of a part in the dry phase. The process allows avoiding problems of dissolution in water and relevant contamination. An air flotation method is used for dry separation. Specially designed machines combining the effects of vibration and air flotation ensure separation of flakes with different specific weight. Such machines are very usefiil for removal of parts of labels that were freed by grounding. An extremely interesting application of this method is the separation of PVC labels from PET bottle flakes. 

Foam mat dryers can only be used to dehydrate liquid foods that are capable of forming stabilized foams. This requirement imposes a restriction on the wide applicability of the method in the food industry because only a few foods, such as whole milk, have a foam-stabilizing capability. Fruit juices have been dried successfully by adding foam stabilizers. Vegetable gum and soluble protein have successfully been used in the food industry as foam-stabilizing agents. 

Freeze drying is the best method for drying highly heat-sensitive or easy oxidizable materials. However, its selection must be governed by economic considerations. Early applications of this method were the drying of blood plasma and serum during World War II. 

Wojdyo, A., Figiel, A., Oszmianski, J., 2009. Effect of drying methods with the application of vacuum microwaves on the bioactive compounds, color, and antioxidant activity of strawberry fruits. J. Agric. Food Chem. 57 1337-1343. 

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