SPECIALISED DRYING METHODS

Superheated-solvent drying in which a material containing non-aqueous moisture is dried by contact with superheated vapours of its own associated liquid, and, 

Solvent dehydration in which water-wet substances are exposed to an atmosphere of a saturated organic solvent vapour. 

The most important applications of solvent dehydration lie within the field of kiln drying for seasoning timber where substantial reductions in drying times have been achieved150 . 

The replacement of air by superheated steam to take up evaporating moisture is attractive in that it provides a high temperature heat source which also gives rise to a much higher 

In tests on the drying of sand, Wenzel and White 53 1 found that the use of steam rather than air did not alter the general characteristics of the drying process, and that the drying rate during the constant rate period was determined by the heat transfer rate. In these tests, the heat transferred by radiation from the steam and surrounding surfaces was 7.5-31 

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UMEs used in our laboratory were constructed by sealing of carbon fibre into low viscosity epoxy resin (see Fig. 32.4) [118]. This method is simple, rapid and no specialised instrumentation is required. Firstly, the fibres are cleaned with this aim. They are immersed in dilute nitric acid (10%), rinsed with distilled water, soaked in acetone, rinsed again with distilled water and dried in an oven at 70°C. A single fibre is then inserted into a 100- iL standard micropipette tip to a distance of 2 cm. A small drop of low-viscosity epoxy resin (A. R. Spurr, California) is carefully applied to the tip of the micropipette. Capillary action pulls the epoxy resin, producing an adequate sealing. The assembly is placed horizontally in a rack and cured at 70°C for 8h to ensure complete polymerization of the resin. After that, the electric contact between the carbon fibre and a metallic wire or rod is made by back-filling the pipette with mercury or conductive epoxy resin. Finally, the micropipette tip is totally filled with epoxy resin to avoid the mobility of the external connection. Then, the carbon fibre UME is ready. An optional protective sheath can be incorporated to prevent electrode damage. 

Starter cultures and probiotics are produced and distributed world wide by specialised companies. Therefore, stabilization of the bacteria is essential. Drying is a common stabilization method as it leads to an increased storage stability and facilitated transport compared to freezing. However, drying leads to an inactivation of the cells. The dehydration damage is especially pronounced at low Water content where structural water is removed from the biomolecules such as proteins and hydrophilic surfaces of biomembranes. 

Decontamination must take place before the patient leaves the hot and warm zones and therefore is best performed at the border of the inner cordon upwind of the threat and in close proximity to the treatment facility. It should only be carried out by trained personnel wear-ing appropriate PPE. Ambulatory casualties should be directed to self-decontamination facilities, initially with dry decontamination by removal of all clothing, which should be disposed of appropriately. If specialised decontamination imits are initially imavailable, improvised methods may be utilised as outlined in Box 5.5. However, no attempt should be made to carry this out imtil appropriate PPE is available. Contaminated casualties may self-present to local hospitals and will require decontamination outside emergency departments. 

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