Crust formation

Krusten-bildung, /. crust formation," incrustation. -tier, n. crustacean, krustieren, v.t. crust, incrust, krustig, a. crusty, crusted. 

By using 300 ml. of methanol at this point, the checkers were able to avoid crust formation on the gas-dispersion tube during ozonolysis (see Note 5). 

Brogli, F. et al., Runaway Reactions, 1981, Paper 3/M, 5-6, 10 Unstable plant-scale operation in the catalysed cyclisation by sodium hydroxide to cyclopropanecarbonitrile was investigated using a bench scale calorimeter. Crust formation on the reactor wall, which caused the erratic operation, was eliminated by using liquid alkali instead of solid. 

Mechanical cleaning of a multitubular stainless steel condenser (blocked by a rigid polyurethane foam) by rodding the tubes was laborious, so chemical cleaning with cone, nitric acid was attempted. When the initial vigorous reaction ( fireworks ) subsided, owing to crust formation, the rod was again inserted, but a sudden explosion occurred which ruptured the condenser. 

Crust formation thus is attributed to the disaggregation of the uppermost soil layer, initiated by the mechanical impact of the rain drops, and the subsequent dispersion of the clay fraction facilitated by the high ESR of the soil and by the low electrolyte content of rain water (Shainberg, 1990). Upon drying, the dispersed clay is responsible for the formation of the hard crust and decreases in infiltration rate. 

Ludden, J. Hynes, A. 2000. The Lithoprobe Abitibi-Grenville transect two billion years of crust formation and recycling in the Precambrian Shield of Canada. Canadian Journal of Earth Sciences, 37, 459-476. 

Figures 10.9S(a,b) show isopleths calculated between (a) corium and siliceous concrete and (b) corium and limestone concrete. Comparison between experimental (Roche et al. 1993) and calculated values for the solidus are in reasonable agreement, but two of the calculated liquidus values are substantially different. However, as the solidus temperature is more critical in the process, the calculations can clearly provide quite good-quality data for use in subsequent process simulations. Solidus values are critical factors in controlling the extent of crust formation between the melt-concrete and melt-atmosphere interface, which can lead to thermal insulation and so produce higher melt temperatures. Also the solidus, and proportions of liquid and solid as a function of temperature, are important input parameters into other software codes which model thermal hydraulic progression and viscosity of the melt (Cole et al. 1984).

It has been found that a decrease in the initial porosity in the food may reduce oil absorption (Pinthus et al., 1995). However, as explained by the authors, crust formation plays an additional and fundamental role as soon as frying commences. As the moisture turns to steam and exits the product, it leaves behind a sponge-like tunnel network, which constitutes the oil reservoir. In accordance, the microstructure of the crust region,... 

Myr after CAIs formed (Bizzarre et al., 2005). Taken together, these data imply that differentiation and crust formation began on the HED parent body 2.5-3 Myr after CAIs formed (Fig. 9.9). This, in turn, implies very rapid accretion, heating, and melting in Vesta, probably within 1 Myr of the origin of the solar system. 

Furthermore, the data presented indicate that a thermally induced rupture of the yeast cells during crust formation is an important step to liberate precursors of the Acp or to liberate the Acp already formed in the interior of the yeast. This would also provide an explanation for the fact that much higher amounts of Acp are present in wheat bread crust compared to the crumb (see chapter by Schieberle and Grosch, this book). 

Comparison of flavor extracts from white cake batter, micro-wave, and conventionally baked cakes have provided insight as to the types of flavor compounds initially present before baking and as to the types of compounds which form (or do not form) during the baking process. Ultimately, this type of information will aid in the formulation of conventionally baked flavors to be added to microwave products. frJien used in conjunction with microwave accessories which promote crust formation, these flavors can benefit the food industry in the development of quality microwave baked products. 

These nonenzymatic reactions are responsible for numerous changes on food properties and may impair food safety. Although these reactions are of great importance in the production of aroma, taste and color, they are often accompanied by a reduction of the nutritive value of different foods and by the formation of toxic compounds harmful for human health (Ledl and Schleicher, 1990). Results of nonenzymatic browning can be either desirable or undesirable. The brown crust formation on bread is desirable the brown discoloration of evaporated and sterilized milk is undesirable. For products in which the browning reaction is favorable, the resulting color and flavor characteristics are generally experienced as pleasant. In other products, color and flavor may become quite unpleasant. 

Increasing water infiltration Maximum infiltration of rainfall water through the soil surface and top layer must be achieved. Crust formation and clogged soil pores (often a result of soil erosion) that promote water run-off should be prevented. Application of compost, incorporation of plant material and mulching are important means of building up organic matter in the topsoil layer, which increases infiltration and improves the rate of water conservation. 

This crust formation or efflorescence results in undesirable agglomerate properties [26]. Strength is reduced to that of the bonded hoop at the surface, with the core of the pellet contributing little or nothing (see Section 4.5). Reduced drying rates result from blocked surface pores [3]. Caking tendencies are increased by the high concentration of soluble material in the surface. 

Agassi, M., 1. Shainberg, and J. Morin. 1981. The effect of electrolyte concentration and soil sodicity on infiltration and crust formation. Soil Sci. Soc. Am. J. 45 848-851,... 

Inadequate heat transfer can be caused not only by an air space, but to an even greater extent by salt crust formation on the inside of the vessel. Hence, mixtures from which salts separate must always be stirred, and the stirrer should come as near to the walls as possible in order to keep them free from incrustation. When large amounts of salt separate, even the best stirrers are inadequate. One case is known where a salt crust only 4 cm. thick resulted in overheating an autoclave to the point where it was red hot. At an internal temperature of 240°C. and pressure of 48 atmospheres, the autoclave was blown out like a balloon and the bottom split. The escaping gas cooled the steel enough so that no further danger was involved. It is almost certain, however, that cast iron would have exploded. (Fusions such as those in the preparation of -naphthol, if done without a metal bath, would certainly ruin any pressure vessel.)... 

FIGURE 8.6 Frames of a motion crust formation and final structure... 

Walker D. (1983) Lunar and terrestrial Crust Formation. Proc. 14th Lunar Planet. Sci. Conf, B17—B25. 

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