Data, temperature range

Correlations for standard-state fugacities at 2ero pressure, for the temperature range 200° to 600°K, were generated for pure fluids using the best available vapor-pressure data. 

Gobalt is a brittle, hard metal, resembling iron and nickel in appearance. It has a metallic permeability of about two thirds that of iron. Gobalt tends to exist as a mixture of two allotropes over a wide temperature range. The transformation is sluggish and accounts in part for the wide variation in reported data on physical properties of cobalt. 

Smoothed data presented at rounded temperatures, such as are available in Tables 6.2 and 6.4, plus the C° values at 298 K listed in Table 6.1 and 6.3, are especially suitable for substitution in the foregoing parabolic equations. The use of such a parabolic fit is appropriate for interpolation, but data extrapolated outside the original temperature range should not be sought. 

Revised material for Section 5 includes the material on surface tension, viscosity, dielectric constant, and dipole moment for organic compounds. In order to include more data at several temperatures, the material has been divided into two separate tables. Material on surface tension and viscosity constitute the first table with 715 entries included is the temperature range of the liquid phase. Material on dielectric constant and dipole... 

The constant, C, is proportional to the ductility of the material in tension the exponent, b, is near 0.5 for most materials over a wide temperature range. This equation applies usually in the range 1—10 cycles, and typical data are shown in Figure 4a (5). The exponent rises when creep or environmental interactions affect fatigue behavior. 

Hydrogen Chloride—Water System. Hydrogen chloride is highly soluble in water and this aqueous solution does not obey Henry s law at ah concentrations. Solubhity data are summarized in Table 5. The relationship between the pressure and vapor composition of unsaturated aqueous hydrochloric acid solutions is given in Reference 12. The vapor—Hquid equiHbria for the water—hydrogen chloride system at pressures up to 1632 kPa and at temperatures ranging from —10 to +70° C are documented in Reference 13. 

Electrical Properties. Polysulfones offer excellent electrical insulative capabiUties and other electrical properties as can be seen from the data in Table 7. The resins exhibit low dielectric constants and dissipation factors even in the GH2 (microwave) frequency range. This performance is retained over a wide temperature range and has permitted appHcations such as printed wiring board substrates, electronic connectors, lighting sockets, business machine components, and automotive fuse housings, to name a few. The desirable electrical properties along with the inherent flame retardancy of polysulfones make these polymers prime candidates in many high temperature electrical and electronic appHcations. 

Stress-relaxation measurements, where stress decay is measured as a function of time at a constant strain, have also been used extensively to predict the long-term behavior of styrene-based plastics (9,12). These tests have also been adapted to measurements in aggressive environments (13). Stress-relaxation measurements are further used to obtain modulus data over a wide temperature range (14). 

The accurate representation of vapor pressure data over a wide temperature range requires an equation of greater complexity. The Wagner equation (eq. 22) expresses the reduced vapor pressure as a function of reduced temperature TIT/... 

The a-form, which crystallines as the kinetic product, is the commercial form of ammonium pentaborate tetrahydrate and the P-form is the thermodynamic product but is slow to crystalline. Its heat capacity has been measured over a broad temperature range (85). Solubihty data are given ia Table 9 and pH data ia Table 10. 

Viscosity is an important property of calcium chloride solutions in terms of engineering design and in appHcation of such solutions to flow through porous media. Data and equations for estimating viscosities of calcium chloride solutions over the temperature range of 20—50°C are available (4). For example, at 25°C and in the concentration range from 0.27 to 5.1 molal (2.87—36.1 wt %) CaCl2, the viscosity increases from 0.96 to 5.10 mPa-s (=cP). 

For additional physical property data over large temperature ranges, see Ref. 120. 

Two empirical parameters are evident in equation 7, the heat of vaporization and the integration constant, I. Experimental data indicate that the linear relationship suggested by Clausius-Clapeyron may not be followed over a large temperature range (4) therefore additional adjustable parameters have been added to equation 7 to improve its correlating abiUty. The most prominent of these is the Antoine equation ... 

Values converted and mostly rounded off from those of Goodwin, NBSIR 77-860, 1977. t = triple point c = critical point. The notation 3.O.—9 signifies 3.0 X 10 . Later tables for the same temperature range for saturation and for the superheat state from 0.1 to 1000 har, 85.5 to 600 K, were published by Younglove, B. A. and J. F. Ely, J. Fhys. Chem. Ref. Data, 16, 4 (1987) 685-721, but the lower temperature saturation tables contain some errors. 

Solid density data are sparse and usually only available over a narrow temperature range, for which the general decrease in density with temperature is approximately linear. 

If data are available over a wide range, all four regression constants (A, B, C, and D) are usually used. Over narrow temperature ranges, only constants A and B are necessary. 

For predicting the liquid viscosity of pm e hydi ocai bon mixtiu es at high temperatiu es, the method of Letsoii and StieP is available. Error analyses with only a small amount of data shows errors averaging 34 percent in the reduced temperature range of 0.76 to 0.98. Equation (2-121) deBnes the method with inputs of Eqs. (2-122) and (2-123). 

The molecules in a gas-hquid interface are in tension and tend to contract to a minimum surface area. This tension may be quantified by the surface tension, which is defined as the force in the plane of the surface per unit length. Jasper" has made a critical evaluation of experimental surface tension data for approximately 2200 pure chem-ic s. He correlates surface tension C (mN/m = dyn/cm) with temperature T (°C) over a specified temperature range as... 

Tyn-Calus This correlation requires data in the form of molar volumes and parachors = ViCp (a property which, over moderate temperature ranges, is nearly constant), measured at the same temperature (not necessarily the temperature of interest). The parachors for the components may also be evaluated at different temperatures from each other. Quale has compiled values of fj for many chemicals. Group contribution methods are available for estimation purposes (Reid et al.). The following suggestions were made by Reid et al. The correlation is constrained to cases in which fig < 30 cP. If the solute is water or if the solute is an organic acid and the solvent is not water or a short-chain alcohol, dimerization of the solute A should be assumed for purposes of estimating its volume and parachor. For example, the appropriate values for water as solute at 25°C are = 37.4 cmVmol and yn = 105.2 cm g Vs mol. Finally, if the solute is nonpolar, the solvent volume and parachor should be multiplied by 8 Ig. 

Data on Illinois No. 6 and Kentucky No. 9 coals were used by Wen and Han (Prepi Pap.—Am. Chem. Soc., Div. Fuel Chem. 20(1) 216-233, 1975) to obtain a rate equation for coal dissolution under hydrogen pressure. These data included a temperature range of 648 to 773 K (705 to 930°F) and pressures up to 13.8 MPa (2000 psia). An empirical rate expression was proposed as... 

A more complex reaction model was proposed from the results of a kinetic study of thermal liquefaction of subbituminous coal. Data were obtained over a temperature range of 673 to 743 K (752 to 878°F) at 13.8 MPa (2000 psia) by using two solvents, hydrogenated anthracene oil (HAO), and hydrogenated phenanthrene oil (HPO), at a coal-solvent ratio of 1 15. Results were correlated with the following model ... 

In the steam reforming reaction, /rC02/p C0 = 2.08 (hr = 5.64) at this temperamre, and at lOOOK the results are hr A = 0.55 for carbon formation, and the PCO2/p CO ratio is 0.155 (hr A = 1.16), and tlrus the tendency for carbon formation passes from zero to unity in tlris temperature range. The presence of CO2 is not indicated in this reaction as given above, but its partial pressure can be obtained from data for the concunent reaction... 

The temperature dependence of the thermal conductivity of CBCF has been examined by several workers [10,13,14]. Typically, models for the thermal conductivity behavior include a density term and two temperaUrre (7) terms, i.e., a T term representing conduction within the fibers, and a term to account for the radiation contribution due to conduction. The thermal conductivity of CBCF (measured perpendicular to the fibers) over the temperature range 600 to 2200 K for four samples is shown in Fig. 6 [14]. The specimen to specimen variability in the insulation, and typical experimental scatter observed in the thermal conductivity data is evident in Fig. 6. The thermal conductivity of CBCF increases with temperature due to the contribution from radiation and thermally induced improvements in fiber structure and conductivity above 1873 K. 

Recently, Dinwiddie et al. [14] reported the effects of short-time, high-temperatme exposures on the temperature dependence of the thermal conductivity of CBCF. Samples were exposed to temperatures ranging from 2673 to 3273 K, for periods of 10, 15, and 20 seconds, to examine the time dependent effects of graphitization on thermal conductivity measured over the temperature range from 673 to 2373 K. Typical experimental data are shown in Figs. 7 and 8 for exposure times of 10 and 20 seconds, respectively. The thermal conductivity was observed to increase with both heat treatment temperature and exposure time. 

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