High moisture

Polyimide. Polyimide is a biaxiaHy oriented high performance film that is tough, flexible, and temperature- and combustion-resistant. Its room temperature properties compare to poly(ethylene terephthalate), but it retains these good characteristics at temperatures above 400°C. Its electrical resistance is good and it is dimensionally stable. The principal detriment is fairly high moisture absorbance. The main uses are for electrical insulation, particularly where high temperatures are prevalent or ionizing radiation is a problem. The films may be coated to reduce water absorption and enhance... 

In a variant of the horizontal form/fill/seal operation, the material, moving in a horizontal direction, is folded on itself vertically. Vertical sections of the two faces are heat-sealed to each other to form a pouch, which may then be filled. The pouch, usually made from film or paper bonded to aluminum foil plus a plastic laminant and heat sealant, is closed by a heat seal. This type of pouch gives high moisture and oxygen protection and is used for moisture-and flavor-sensitive condiments and beverage mixes. 

Each food or food ingredient shows a characteristic equiHbrium relative humidity at a given moisture content and temperature. Thus as a food is dried and its moisture content is reduced from its fresh value where water activity is generally 1.0, to lower and lower values, the equiHbrium water activity of the food decreases as a complex function of residual moisture. The shape of the equiHbrium relative humidity—moisture content curve is set by the chemistry of the food. Foods high ia fmctose, for example, biad water and thus show lower water activities at high moisture contents. Dried pmnes and raisias are examples. Drying can be terminated at any desired moisture content and hence any water activity. 

There are many interacting parameters and possible feedstock—process—product combinations, but all are not feasible from a practical standpoint eg, the separation of small amounts of metals present in biomass and the direct combustion of high moisture content algae are technically possible, but energetically unfavorable. 

Drying. In many cases, the high moisture content of young coals dictates significant drying (qv) before use. In some cases, partial removal of mineral matter, especially water-soluble species, is desirable. 

A high, moisture content necessitates finer grinding of coal for rapid water release. For such coals, the classifier in the pulverizer is set to return more of the oversize material for further grinding. 

In theory, whole-tree-energy plants have the potential to be more efficient than existing wood-fired generators, which are fueled by chipped wood with a relatively high moisture content (45%). The dried whole trees have a moisture content below 25%, and whole-tree plants potentially can be built to have a greater capacity and to employ high pressure, high temperature steam. 

Glass Frosting. Deposition of siUcon dioxide is used to impart a translucent coating on glass (qv) (50). The surfaces are either exposed to tetraethoxysilane or tetramethoxysilane under high moisture conditions, or the alkoxysilanes are ignited and the resulting powder is appHed to the surface. 

As energy costs have escalated in recent years, the use of high moisture food by-products in commercial animal feeds has also escalated, particularly in beef cattie and dairy rations, as a means of reducing production costs. Because of the broad activity spectmm, sorbates are extremely effective in the preservation of wet by-products, eg, brewers and distillers grains, beet pulp, citms pulp, and condensed whey (139). 

Moisture. Moisture is usually determined by a vacuum oven-dry method at 80°C. Moisture levels of more than 0.05% are likely to lead to caking or lumping problems which can make storage and transfer of bulk sugar difficult. The usual standard is 0.03%, which manufacturers can easily meet. Care must be taken to avoid temperature differentials ia storage which cause moisture to migra te and estabUsh pockets of unacceptably high moisture levels. 

Resoles can be cured by the addition of base or by heat alone. Their shelf life is thus limited, which is a significant deterrent to their use in fiber-reinforced composites. Resoles are often used in unreinforced appHcations in electronics and high moisture areas. 

The highly polar nature of the TGMDA—DDS system results in high moisture absorption. The plasticization of epoxy matrices by absorbed water and its effect on composite properties have been well documented. As can be seen from Table 4, the TGMDA system can absorb as much as 6.5% (by weight) water (4). This absorbed water results in a dramatic drop in both the glass transition temperature and hot—wet flexural modulus (4—6). 

Environment Electrostatic precipitator receives air from steel blast furnace 50-180°F (10-82°C) high moisture, chlorides, sulfides and sulfate, iron oxides... 

The copper complex 1s available from Strem Chemicals, Inc., under the name cuprous triflate (benzene complex). The checkers recommend handling the material In a dry box because of Its high moisture and air sensitivity. 

Certain copolymers of this type have been found to have excellent gas barrier properties, with the dry polymer having an oxygen permeability only about 1/lOth that of polyvinylidene chloride. Unsurprisingly, the copolymer has a high moisture absorption and a high moisture vapour transmission rate. Where the material is swollen by water, gas permeability is also higher. 

They can be breathable with high moisture vapor transmission. 

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