Explore: Coefficient

Plastics have evolved into sophisticated food packages. This evolution requires flavor management from the package. Flavor loss can occur from a variety of mechanisms. Of particular interest are flavor losses that result from interactions of flavor molecules with the package. This paper presents the permeability, P, and the component parts, the diffusion coefficient, D, and the solubility coefficient, S, for selected flavor molecules. Use of these parameters to estimate flavor loss is included. The effects of temperature, humidity, concentration of the flavor, combination of flavors, size of the flavor molecule, and type of flavor molecule on the diffusion and solubility coefficients are discussed.

Composite materials such as concrete usually are not composed of materials of the same coefficient of thermal expansion, and, therefore, temperature changes cause stresses in their components. In the paper, two simple equations are derived--one for tensile stress in binding material, and the other for tensile stress in aggregate. If coefficients of thermal expansion of aggregate and binder differ too much, large diurnal or seasonal temperature changes cause in portland cement concrete excessive tensile stresses in hardened cement paste, and in polymer concrete excessive tensile stresses in aggregate. So, for certain climatic conditions, and with known elastic and thermal properties of components, by using derived equations, it is possible to calculate tensile stresses in binder or aggregate, and estimate if they affect durability of concrete or some other material with two components. Typical applications of the derived equations are in the cases of the Middle East concretes or polymer concretes.