Moisture Migration

Ziegler, G.R., MacMillian, B., and Balcom, B.J. 2003. Moisture migration in starch molding operations as observed by magnetic resonance imaging. Food Res. Int. 36, 331-340. 

More recently, moisture migration towards growing ice cry-... 

Although not the primary function, the retardation of moisture migration into insulated spaces, where condensation may occur, is an important engineering consideration in the design of thermal insulation systems. 

The second method is to separate the components and measure each individually. Since water activity is a driving force for moisture migration, it might be necessary to know the water activity values for the individual components. For example, in a flake cereal with fruit pieces, it might be important to know the individual component water activities. The water activity of the cereal flakes and fruit pieces should be as close as possible to prevent moisture migration, which would cause the flakes to become soggy and the fruit pieces to become hard and brittle. 

Dimensional changes due to moisture migration, thermal expansion, etc., are generally greater than with other materials. 

Ghosh, V., Ziegler, G.R., and Anantheswaran, R.C. (2005). Moisture migration through chocolate-flavored eonfeetionery coatings. J. Food Eng. 66, 177 186. 

Low Temperature [-101 to -1°C (-150 to -l-30°F)] Cellular glass, glass fiber, polyurethane foam, and polystyrene foam are frequently used for this service range. A vapor-retarder finish with a perm rating less than 0.02 is required. In addition, it is good practice to coat all contact surfaces of the insulation with a vapor-retardant mastic to prevent moisture migration when the finish is damaged or is not properly maintained. Closed-cell insulation should not be relied... 

In a survey of recent Soviet research on the drying of solids, Fulford (F3) outlined the importance of internal moisture migration and suggested various approaches to determine the rate of moisture movement. The results of Soviet research showed that there seems to be a trend to applying the capillarity concept to describe moisture flow during the drying. The approach is very similar to that described in this section. 

Moisture migration in the walls, floors, or ceilings of buildings and in other applications is controlled by either vapor barriers or vapor retarders. Vapor barriers are materials that are impermeable to moisture, such as sheet metals. 

There are a number of variables that influenee panel formation. They include press temperature, press time, moisture eontent, glue formulation, and modulation of the pressure. The influenee of these variables is diseussed further when considering the manufacture of fibreboard and partieleboard (Chapter 12). The trend to pressing high moisture content veneer suggests that moisture migration through the veneers will contribute more to heat transfer than hitherto. 

Precautions should be taken to prevent moisture migration that increases the load on the HVAC system. 

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