Specific Gravity of the Composite

It was mentioned above that composite deck boards are porous by virtue of their manufacturing. The pores are typically open and interconnected, forming chains of cavities. Air oxygen flows in, through these pores, and effectively oxidizes composite materials from inside, particularly at elevated temperatures, which often take place on the surface of decks. 

As a result, neat HDPE-made shapes, for example, are oxidized only from the surface, whereas HDPE-based composite profiles (as other composites) are oxidized largely from within, wherever air oxygen can penetrate through pores. Inner surface, available to oxygen, is sometimes hundreds of times larger, compared to the outer surface of plastics, available to oxygen. Pore volume of composite materials available to 

Besides water absorption, another approach for estimations of an inner volume of composites is as follows. Let us consider two composite materials, Trex and Geo-Deck. Trex composites consists of two major ingredients (50 50), that is, polyethylene (density 0.94 g/cm ) and wood flour (density 1.30 g/cm ). Hence, the overall specihc gravity of Trex composites should be 1.12 g/cm (0.94 X 0.5 + 1.30 X 0.5). In reality, it is 0.94 g/cm If we assume that the difference between the two figures is due to porosity, the latter is equal to 19%. That is, about one-fifth of the whole volume of the composite material is open for oxygen to destroy plastic from within the material. 

GeoDeck s overall density should be equal to 1.24 g/cm. Therefore, when GeoDeck board has specihc gravity of 1.06 g/cm, its porosity is 17%, and when it is of 1.23 g/cm its porosity is only 0.8%. Hence, the last material is more than 20 times less likely to suffer from oxidative degradation compared to the hrst one. In a simplihed manner, it will serve 20 times longer. This was conhrmed by direct experiments in the weathering box (Table 15.12 below). 

Certainly, the density of a composite material is only one of the factors that determine the rate of the oxidative degradation of the composite material. However, all condihons equal, density plays a very signihcant role in determining the lifetime of a deck board. 

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Figure 12.13 Effect of HDPE content (horizontal axis) in WPC material on density (specific gravity) of the composite and its water absorption (data in Table 12.13).

The hardness of the UDPNCs (uniformly dispersed polymeric nanocomposites) was measured according to ASTM D-2240 with a shore durometer. Specific gravity of the composite for respective loading was calculated from the density values of the compounds. 

QuaHty control in the production of organic solvent finish removers may be done by gas—Hquid chromatography, which allows the manufacturer to determine the actual ratio of volatile solvent present in the finished product. If the product does not meet specifications, solvents can be added to bring the product to an acceptable composition. A less expensive approach is to use a hydrometer to determine the specific gravity of the product. The specific gravity indicates if the proper blend has been reached. Nonaqueous acid—base titration may be used to determine the amount of acid or alkaline activator present in a remover. 

The resulting melt is cooled lapidly to prevent reversion to calcium cyanamide. The product is marketed in the form of flakes, dark gray because of the presence of carbon. Typical composition is shown in Table 7. Because the rate of hydrogen cyanide evolution is relatively high, it is readily adaptable to fumigation. Specific gravity of the product is 1.8 to 1.9. The price of black cyanide is generally lower than sodium cyanide it is manufactured in Canada and South Africa. 

Some work has been done to correlate oxide CMP performance with pad properties [46]. This work indicated that the specific gravity of the pads and the cross-linking densities affect polish performance. Other work has been done to correlate CMP performance with slurry composition [47]. This work suggests that the friction during polish is proportional to the removal rate when the abrasive content is greater than 10%, and inversely proportional to the removal rate when it is less than 10%. 

N = normality of the NaOH soln Retest. Retest the lot if the results of tests of the composite and the individoal samples vary over a range greater than 0.335 Water. Determine the water content of a 50-ml specimen of the EtnO as specified in ASTM Standard D1364. Calculate the weight of the specimen tested using the specific gravity of the ethylene oxide determined by means of a suitable hydrometer... 

Answer—yes But why Well, the liquid is cooled by 5°F after it leaves the drum. The cooled liquid is not in equilibrium with the vapor in the drum. It has been subcooled by 5°F. This means that the bubble-point liquid has been cooled, without altering its composition. The vapor pressure of the liquid has been reduced. As can be seen in Fig. 25.3, subcooling this particular liquid by 5°F reduces its vapor pressure by about 2 psi. As the specific gravity of the liquid is 0.58, this is equivalent to an increase in the NPSH by 8 ft. Once again, our objective is to increase the flow from 250 to 300 GPM. Figure 25.2 tells us that the required NPSH increases from 20 to 26 ft. However, when we subcool the liquid by 5°F, the available NPSH increases from 20 to 28 ft. As the available NPSH now exceeds the required NPSH by 2 ft, the flow can be increased without risk of pump cavitation. 

Dry gases are the easiest to deal with because no liquid condenses from the gas as it moves from the reservoir to the surface. The composition of the surface gas is equal to the composition of the gas in the reservoir, and the specific gravity of the surface gas is equal to the specific gravity of the reservoir gas. Thus, a gas sample taken at the surface can be analyzed and the resulting composition or specific gravity used in correlations to determine the properties of the gas in the reservoir. 

If compositional analysis is unavailable, the engineer must rely on production data to estimate the specific gravity of the reservoir gas. Other properties.of the reservoir gas are estimated using specific gravity. 

The specific gravities of the separator gas and stock-tank gas are measured, Often the composition of the separator gas is determined. 

Often, the only property of the surface liquid that is known is the specific gravity—although the composition of the gas associated with that liquid is known. In this situation, the procedure given in the previous section can be used to estimate the density of the liquid at reservoir conditions with comparable accuracy by simply considering the surface liquid as a single component. 

Step 7 The compositions of the gases and liquids can be used to calculate various properties. Example 6-12 is a calculation of the heating value of die separator gas. Example 7-9 is a calculation of liquids content of the separator gas. Specific gravities of the gases can be calculated. 

When the hydrochloric acid has cooled to room temperature determine the volume and the specific gravity of the solution in both absorption bottles. Use either a hydrometer or the apparatus shown in Fig. 19. Consult the table on page 371 and determine the percentage composition of the preparation. Calculate the weight of hydrogen chloride obtained, the normality of the solution, and the percentage yield. 

Stamm AJ, Sanders FIT (1966) Specific gravity of the wood substance of loblolly pine as affected by chemical composition Tappi 49 397-400 Tolansky S (1968) Interference microscopy for the biologist Charles C Thomas, Springfield, Illinois, USA, 166 pp... 

Various methods can be used to determine the amounts of monoethylaniline and diethylaniline in a given tra xture. One method depends on the determination of the temperature increase occurring when a prescribed amount of the base mixture is mixed with an accurately measured amount of pure acetic anhydride. More reliable and accurate results are obtained, however, by determining the specific gravity of the mixture. From the table below, the composition of the mixture can be determined directly, and with great accuracy, from the density at 15 . It is necessary, of course, that no unchanged aniline be present. This condition is fulfilled in the procedures described above. 

The second, experimental part of the Opuscules consists of three genres of experiments, accurately reflecting Lavoisier s work during the previous year—a review of the principal experiments involved in the Black-Meyer controversy, the calcination of metals, and the combustion of phosphorus and sulphur. In the first three chapters, Lavoisier repeated the experiments related to the main controversy to prove that the same elastic fluid was involved in them. He maintained a quantitative thread by tracking the specific gravity of the air produced in each experiment. In the plan and execution of these experiments, he assumed that a chemical substance was uniquely defined by its composition (constituents and... 

To apply the above method to mixtures, it is necessary to know the gas composition in order to calculate the pseudo-eriticals. If data on the composition are not available, it is still possible to approximate a value for Z if the specific gravity of the gas is known. It has been found that if the pseudo-oritioal pressure is plotted as a function of specific gravity for a large number of gases, most points fall on a straight line. Similarly, a plot of pseudo-critical temperature versus... 

Effect of Oil Composition. Experimental data on the gas solubility in numerous crude oils indicate that the solubility increases as the specific gravity of the oil decreases. A low liquid gravity indicates the presence of appreciable concentrations of low molecular weight liquid hydrocarbons. Consequently there is a greater chemical similarity between the gas and the oil and a greater gas solubility is to be expected. 

A liquid mixture containing 45.0% benzene (B) and 55.0% toluene (T) by mass is fed to a distillation column. A product stream leaving the top of the column (the overhead product) contains 95.0mole% B, and a bottom product stream contains 8.0% of the benzene fed to the column (meaning that 92% of the benzene leaves with the overhead product). The volumetric flow rate of the feed stream is 2000 L/h and the specific gravity of the feed mixture is 0.872. Determine the mass flow rate of the overhead product stream and the mass flow rate and composition (mass fractions) of the bottom product stream. 

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