Immersion type comparison

The general type of approach, that is, the comparison of an experimental heat of immersion with the expected value per square centimeter, has been discussed and implemented by numerous authors [21,22]. It is possible, for example, to estimate sv - sl from adsorption data or from the so-called isosteric heat of adsorption (see Section XVII-12B). In many cases where approximate relative areas only are desired, as with coals or other natural products, the heat of immersion method has much to recommend it. In the case of microporous adsorbents surface areas from heats of immersion can be larger than those from adsorption studies [23], but the former are the more correct [24]. 

In the present work, steel surfaces polished, phosphated and painted are studied using AC Impedance technique In order to evaluate the protection efficiency of a commercial phosphatlng solution. The AC Impedance behavior of painted metal has been correlated with the Immersion time In the phosphatlng solution and with the desirability of a phospho-chromic rinse (18-23). A comparison of the Impedance behavior of two different types of commercial paints Is made for various durations of Immersion In sodium chloride solution at room temperature, and also for various temperatures at a given duration of Immersion. 

Tissue penetration of endotamponade media should be avoided because of non-calculable side effects. One way to reduce the penetration rate is the use of branched species. In a similar experiment as described above, small pieces of fatty tissue and muscle tissue from pig were immersed in the test liquids for 15 min and then rinsed with PFD to clean the surfaces. Table 13 shows the reduced ratio of penetration of branched perfluorobutyl-butane in comparison to the linear form (044 perfluorobutyl-n-butane and 044v 1-perfluorbutyl-2-methyl-propane, own unpublished results). The relative penetration ratio was determined on the basis of the concentration of the two types of perfluorobutyl-butane indicated by GC/MS measurements. 

The drying shrinkage of concrete containing calcium chloride is increased in comparison to plain concrete, even though the amount of moisture lost is less [22]. This is illustrated in Fig. 5.37 and it is thought that the reduced moisture loss will be due to the more advanced state of hydration in the specimens containing calcium chloride. The increased shrinkage must, therefore, be a characteristic of the type of cement hydration products formed. Under saturated conditions, such as total water immersion, the amount of expansion of the concrete is reduced when calcium chloride is present. 

Figure 10.5 shows the data obtained on an epoxy-nitrile film adhesive on 5052-H34 aluminum alloy after immersion in hot water for 50, 100, 300, 500, and 1000 hours. This test is very useful because it permits a large number of adhesive-bonded specimens with different adhesives, adher-ends, and surface pretreatments to be tested at the same time with a relatively small investment in man hours and equipment. Figure 10.6 shows a comparison of the stressed-durability data and unstressed hot-water-soak data on the same epoxy-nitrile film adhesive, using 2024-T3 aluminum alloy. Note the parallelism of the plots. The curve in the lower left was obtained when lap-shear specimens were subjected to various levels of stress and then exposed to an environment of 60°C and 95% RH until failure. The failure time is plotted as a log function. The curve in the upper right portion is a plot of the data when the same types of lap-shear specimens were subjected to 60°C water for specified periods of time and then tested for their residual strength. In the first case, failure time was recorded. In the latter case, residual strength was determined. The same type of data is obtained with both curves. ... 

To compensate for the dopant anions, the as-grown film was immersed in an ammonia solution, which caused the film to undergo a color change from black to red [373]. The undoped film had a conductivity of about 10 S cm" at room temperature. Exposure of the film to iodine vapor increased the conductivity to 10" S cm". The maximum conductivity achieved was 10" S cm". Elemental analysis of the polynaphthalene film gave a carbon-to-hydrogen ratio of 1.60 1 in comparison with the calculated ratio of 1.67 1. The infrared spectra matched that of poly-2,6-naphthylene prepared by a chemical Grignard-type polymerization [373J. 

It is worth mentioning that at 0.6 M NaCI concentration for 46 days, the corrosion rate for CS and WS were of 3l00 xm per year and 3686 xm per year, respectively. For comparison purposes, it is possible to see that the performance of both steels in such aggressive environments of high chloride content is very poor, but it is even three to five times worse than in the case of total immersion tests. These corrosion rates seem to be inversely related to the iron conversion factor, which is lower (about 0.21) in the immersion tests than in the dry-wet tests (about 0.80). The different behaviors should be related to the type of iron phases, their characteristics, and their relative amounts. 

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