Saturation point

Crystallization. Acidified aluminum sulfate solutions can be supercooled 10 °C or more below the saturation point. However, once nucleation begins, the crystallization rate is rapid and the supersaturated solution sets up. The onset of nucleation in a gentiy stirred supersaturated solution is marked by the appearance of silky, curling streamers of microscopic nuclei resulting from orientation effects of hydraulic currents on the thin, platelike crystals. Without agitation, nucleation in an acidified solution, in glass tubes, can yield extended crystalline membranes of such thinness to exhibit colors resulting from optical interference. 

At red heat, a low carbon ferrous metal, in contact with carbonaceous material such as charcoal, absorbed carbon that, up to the saturation point of about 1.70%, varied in amount according to the time the metal was in contact with the carbon and the temperature at which the process was conducted. A type of muffle furnace or pot furnace was used and the kon and charcoal were packed in alternate layers. 

The reaction involves two electrons per thionyl chloride [7719-09-7] molecule (40). Also, one of the products, SO2, is a Hquid under the internal pressure of the cell, facihtating a more complete use of the reactant. Finally, no cosolvent is required for the solution, because thionyl chloride is a Hquid having only a modest vapor pressure at room temperature. The electrolyte salt most commonly used is lithium aluminum chloride [14024-11-4] LiAlCl. Initially, the sulfur product is also soluble in the electrolyte, but as the composition changes to a higher SO2 concentration and sulfur [7704-34-9] huA.ds up, a saturation point is reached and the sulfur precipitates. 

Fiber saturation point is the bound moisture content of ceUular materials such as wood. 

Fiber-saturation point is the moisture content of celhilar materials (e.g., wood) at which the cell walls are completely saturated while the cavities are liquid-free. It may be defined as the equihbrium moisture content as the humidity of the surrounding atmosphere approaches saturation. 

Capillary Flow Moisture which is held in the interstices of solids, as liquid on the surface, or as free moisture in cell cavities, moves by gravity and capiUarity, provided that passageways for continuous flow are present. In diying, liquid flow resulting from capiUarity appUes to liquids not held in solution and to aU moisture above the fiber-saturation point, as in textiles, paper, and leather, and to all moisture above the equiUbrium moisture content at atmospheric saturations, as in fine powders and granular solids, such as paint pigments, minerals, clays, soU, and sand. 

Figure 18.4 The hanging-drop method of protein crystallization, (a) About 10 pi of a 10 mg/ml protein solution in a buffer with added precipitant—such as ammonium sulfate, at a concentration below that at which it causes the protein to precipitate—is put on a thin glass plate that is sealed upside down on the top of a small container. In the container there is about 1 ml of concentrated precipitant solution. Equilibrium between the drop and the container is slowly reached through vapor diffusion, the precipitant concentration in the drop is increased by loss of water to the reservoir, and once the saturation point is reached the protein slowly comes out of solution. If other conditions such as pH and temperature are right, protein crystals will occur in the drop, (b) Crystals of recombinant enzyme RuBisCo from Anacystis nidulans formed by the hanging-drop method. (Courtesy of Janet Newman, Uppsala, who produced these crystals.)...

If, in addition, the air is humidified so that it reaches the saturation point, with the corresponding temperature we will now use the notations... 

The presence of moisture on steel above the critical humidity but below the saturation point may be caused by an adsorption mechanism or by the presence of particles of deliquescent salts on the surface. Once rusting has begun, the composition of the rust already formed will influence the relative humidity at which further rusting will occur, because rusts formed in polluted atmospheres contain hygroscopic salts. The method by which moisture reaches the surface is probably less important, however, than the length... 

The data should indicate the temperature and time of immersion and the percentage of weight gain of a test specimen. The same applies to data at the saturation point of 73.4°F (23°C), and, if the material is usable at 212°F (100°C), also to saturation at this temperature. 

B. l0-Bromo-ll-hydroxy-10,ll-dihydrofarnesyl Acetate [2,6-Dodeca-diene-1,11-diol, 10-bromo-3,7, -trimethyl-, 1-acetate, (E,E)-]. Farnesyl acetate (29 g., 0.11 mole) is dissolved in 1 1. of /erf-butyl alcohol (Note 4) contained in a 3-1. Erlenmeyer flask. Water is added (500 ml.), and the solution is cooled to about 12° using an external ice water bath. Maintaining this temperature, rapid magnetic stirring is begun, and more water is added until a saturated solution is obtained. The second addition of water may be rapid initially, but the saturation point must be approached carefully, like the end point of a titration. A total of about 1200 ml. of water is required for the above amounts of farnesyl acetate and ferf-butyl alcohol. The solution must remain clear and homogeneous at about 12°, and if the saturation point is accidentally passed by adding too much water, ferf-butyl alcohol should be added to remove the turbidity. 

If additional heat is applied within the confines of a pressure vessel, the pressure of the steam increases and the boiling point is raised, requiring yet more heat energy to reach the new saturation point. 

The application of heat beyond the saturation point results in superheated steam and a further increase in steam temperature. Superheated steam is particularly useful in power generation boilers because the heat-... 

Maintaining condensate temperatures at or near saturation points to minimize carbonic acid formation. This includes heating intermediate condensate receivers to maximum practical temperatures. 

In arid environments, where the soluble products of weathering are not completely removed from the soil, saline solutions may circulate in the soil as well as in rock fractures. If upon evaporation the salt concentration increases above its saturation point, salt crystals form and grow (Goudie et al, 1970). The growth of salt crystals in crevices can force open fractures. Salt weathering occurs in cold or hot deserts or areas where salts accumulate. Boulders, blocks. 

From the qualitative analysis, Chan found that students mental models could be categorized into three types initial, synthetic, and scientific mental models (Fig. 11.4). The initial model refers to the static model, which had only solute dissolved into the solution and then stopped at the saturation point. The synthetic model refers to the coexistence of two models the unidirectional model and... 

FIGURE 68 Wooden bowl. A wooden bowl made of boxwood, first century c.e., from Qumran, Israel the wood used to make the bowl seems to have been imported from Turkey. The excellent preservation of the bowl is due to extremely hot and dry environmental conditions in the region. Three conditions are necessary for wood to decay (1) a favorable temperature (0-32°C), (2) moisture in excess of the fiber saturation point (above 25-30%) and (3) an adequate supply of oxygen. If any one of these is eliminated wood remains well preserved for long periods of time. 

The fluid is undersaturated if Qi is less than A). This condition indicates that Reaction 3.34 has not proceeded to the right far enough to reach the saturation point, either because the water has not been in contact with sufficient amounts of the mineral or has not reacted with the mineral long enough. Values of Qi greater than A), on the other hand, indicate that the reaction needs to proceed to the left to reach equilibrium. In this case, the fluid is supersaturated with respect to the mineral. 

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