Bubble rapid heating

The rapid formation of a liquid can entrap a portion of the air which initially occupies the space between particles, and result in bubble formation. Rapid heating of such a melt can lead to expansion of these bubbles and foaming of the melt. It is possible for the foaming due to trapped air to cause the melt to rise above the upper rim of a crucible, if the crucible is initially filled to the top with batch. Since glass forming melts are usually very efficient at dissolving the bottom of furnaces, care should always be taken to ensure that this does not occur. 

The entry zone where the food is rapidly heated and is covered in a few seconds with small steam bubbles, more or less uniform in size and distribution. Bubbles keep the food pieces separated and. 

C. T. Avedisian, W. S. Osbourne, F. D. McLeod, and C. M. Curley Measuring bubble nucleation temperature on the surface of a rapidly heated thermal inkjet heater immersed in a pool of water. Proceedings of the Royal Society of London, Series A, 455, 3875-3899... 

Thermal inkjet printheads produce ink droplets from the thermal vaporization of the ink solvent (25). In the inkjet process, a resistor is rapidly heated to produce a vapor bubble, which subsequently ejects a droplet from the orifice. 

If the effective absorption coefficient of the material with respect to the external radiation is small, a large amount of the material beneath the surface is heated, which slows the rate at which the material approaches its degradation temperature range. However if the effective absorption coefficient is large, most of the radiation is absorbed close to the surface and a thin layer of the material is rapidly heated to its degradation temperature range. In this case, the ignition delay time becomes shorter for the same external radiant flux [11]. Also, the maximum temperature occurs in the surface material instead of below the surface with in depth absorption [11,12]. Two different temperature distributions are shown in Fig. 1.1. The solid line is the temperature distribution for an opaque material, and the dashed line is for a diathermic material. Bubbles are often formed at or near the surface of a thermoplastic sample [13]. 

The entry zone where the food is rapidly heated and is covered in a few seconds with small steam bubbles, more or less uniform in size and distribution. Bubbles keep the food pieces separated and, along with the flow of oil, prevent clump formation. Mechanical pressure or even pressure due to excessive oil flow that would force the food pieces into close contact must be avoided in the entry zone. The food must move freely with the aid of a smooth oil flow. At the end of the entry zone a breaker bar or any other appropriate device may be used for the separation of any clumps that have been formed. Starch, in starch containing foods like savory snacks and potato products, begins to gelatinize in the entry zone, first on the surface and later through to the interior. 

In order to achieve rapid heat transfer and temperature uniformity, the reactant gas flow velocity should be high enough at least to form gas bubbles in the catalyst bed. However, the need for large-scale operation and relatively small catalyst particles makes operation in the slug... 

Sometimes an air bubble enters the tube E and prevents the regular flow of liquid from B the air bubble is easily removed by shaking the rubber tube. The flask A is heated (e.g., by a ring burner) so that distillation proceeds at a rapid rate the process is a continuous one. If the liquid to be steam distilled is lighter than water, the receiver must be modified so that the aqueous liquors are drawn off from the bottom (see Continvmia Extraction of Liquids, Section H, 44). 

Heat is used to darken amber, ivory, and jade to simulate age. Pieces of amber and tortoiseshell can be reconstmcted, ie, joined under heat and moderate pressure. By careful heating in oil, milky amber can be clarified when the gas and water within small bubbles diffuse out of the stone. If heating is rapid, the attractive sun-spangle cracking shown in Figure 1 results. 

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