Stability Maps

FIG. 15 A comprehensive stability map illustrating the general relationship between the occurrence of various reactions important in foods, as a function of water activity, superimposed on a sorption isotherm. M, mold Y, yeast B, bacteria. The isotherm is plotted as moisture content (left y axis) versus water activity, whereas all other curves are plotted as relative reaction rate (right y axis) versus water activity. Additional information corresponding to regions I, II, and III is given in Table IV. 

Labuza et al. (1970) originally partitioned the stability map into three zones zone I ranged from 0.0 to 0.25 aw, zone II ranged from 0.25 to 0.80 aw,... 

LIG. 37 Stability map for dairy powders containing amorphous lactose. The critical water activity (0.37 aw) corresponds to the water activity of amorphous lactose with Tg of 24 °C (and a moisture content of 6.8 g water/100 g solids) [reproduced with permission from Roos (2003)]. 

Figure 6.9 (a) The pair interaction force for a polystyrene particle with a I pm radius and Ka = 100 with a steric barrier of about 2nm. (b) The stability map for the system with the pair potential shown in Figure 6.9(a). The applied shear is represented by the Peclet number Pe versus the surface potential ij/0... 

Villars, P., Mathis, K. and Hulliger, F. (1989) Environment classification and structural stability maps. In The Structures of Binary Compounds, eds. de Boer, F. and Pettifor, D. (North-Holland, Amsterdam), Vol. 2, p. 1. 

Stability maps and correlation diagrams. As a concluding remark to some topics considered in this chapter and a recapitulation of procedures often employed in the description and classification of intermetallic systems, a little additional information about correlation diagrams is included here. 

Pettifor s structure maps additional remarks. We have seen that in a phenomenological approach to the systematics of the crystal structures (and of other phase properties) several types of coordinates, derived from physical atomic properties, have been used for the preparation of (two-, three-dimensional) stability maps. Differences, sums, ratios of properties such as electronegativities, atomic radii and valence-electron numbers have been used. These variables, however, as stressed, for instance, by Villars et al. (1989) do not always clearly differentiate between chemically different atoms. 

Prediction of the properties of selected families of alloys Gschneidner s relations as an example. Stability maps and/or correlation diagrams... 

The marginal stability envelopes are shifted when a bias voltage is applied, and recently Iwamoto et al. (1991) prepared a number of stability maps showing the effects of bias voltage. They solved the governing equations numerically. 

Figure 20.12 shows a stability map of the conical preburner system investigated. In developing the stability map, the fuel flow rate is maintained constant at 0.36 g/s while the primary and secondary air flow rates are varied systematically. The flame is considered to be stable if it could be sustained for a long period of time. As shown in Fig. 20.12, unstable regimes can be noted both for low and high secondary air flow rates. 

Figure 6.5 Equilibrium void stability map for a typical epoxy resin system. Curves indicate stable void equilibrium states for liquid-resin pressures indicated. Growth takes place above the lines and dissolution occurs below the lines for any given resin pressure...

A plot of Equation 6.32 for two relative humidities (50 and 100%) yields a void stability map, which is shown in Figure 6.10. It is evident from this map that vacuum can be applied... 

Figure 6.10 Void stability map for pure water void formation in epoxy matrixes. Note the significant effect of initial relative humidity exposure of the resin...

A pressure-temperature stability map can be constructed as a function of humidity exposure, which identifies the resin pressure values for each temperature below which void growth is possible and above which voids cannot grow but rather tend to collapse via dissolution. 

Figure 7.17 Stability map for non-fat milk solids showing schematic rates of various deteriorative changes and growth of micro-organisms as a function of water activity (from Roos,...

Figure A2.2.1 Water activity stability map (adapted form Labuza, 1970). A representation of a typical sorption isotherm for food materials and of the effects of water activity on the relative reaction rates of several chemical processes, as well as the growth of microorganisms, in foods are shown.

The water activity of a food describes the energy status of water in a food and, hence, its availability to act as a solvent and participate in chemical or biochemical reactions (Labuza, 1977). Figure A2.2.1 is a global stability map of foods, showing stability as a function of aw (Labuza, 1970). Water s ability to act as a solvent, medium, and reactant increases with increasing water activity (Labuza, 1975). 

The effect of the pH on suspension stability was measured and is shown in a so-called stability map, see Figure 6. 

A plot of Eq. (32) for two relative humidities (50 and 100%) yields a void stability map which is shown in Fig. 10. It is evident from this map that vacuum can be applied without encouraging void growth if such application is coordinated with the temperature of the system. Brown and McKague 14) have experimentally observed that the void content is reduced significantly when pressure is applied to the prepreg early in the cycle, which is in accordance with the stability map. 

Figure 2. Stability Map with Dominating Flow Effect.

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