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Density values, measurement

I, the extremely low concentration of polymer in the fractions collected reduced the precision in the ultraviolet optical density values measured, the influence of which is amplified in the figures in the last column. Therefore, the average styrene content was used as the composition of the peak point to calculate the MW of the polymer by Equation 5. The MW of the styrene homopolymer which is present in small amounts was taken as the MW of the first block, as explained above. In this manner the molecular structure of the polymer was found to be S( 15,000) B(61,000)S( 14,000) the figures given in parentheses being the MW s of the successive blocks. [Pg.168]

Weight losses measured during the transformation indicated that the two phases differed in their chemical composition. Assuming a MoS2 —> MoNx reaction, the x values were close to 1.2 and 1.0 for L-MoN and H-MoN respectively. Analysis of nitrogen and sulphur were again performed in a LECO analyser. N was determined as before, while S was detected as S02 by an infrared method. The results are reported in Table 13.9 as well as the density values measured in tetrachloromethane. [Pg.146]

Methods of measurement of coal density include use of a gas pycnometer and particle density by mercury porosimetry. However, the difference in density values using different gases must be recognized since, for example, density values measured by nitrogen may be greater than those obtained when helium is used. Density measurement depends on adsorption of gas molecules, and differences (between nitrogen and helium) may be due to nitrogen adsorption on the coal surface. [Pg.113]

Fig. 2.4 Comparison of wet bulk densities determined on discrete samples by weight and volume measurements and calculated from gamma ray attenuation, (a) Cross plot of wet bulk densities of gravity cores PS 1821-6 from the Antarctic and PS1725-2 from the Arctic Ocean. The dashed lines indicate a difference of 5% between both data sets, (b) Wet bulk density logs derived from gamma ray attenuation for two 1 m long core sections of gravity core PS1725-2. Superimposed are density values measured on discrete samples. Modified after Gerland and Villinger (1995). Fig. 2.4 Comparison of wet bulk densities determined on discrete samples by weight and volume measurements and calculated from gamma ray attenuation, (a) Cross plot of wet bulk densities of gravity cores PS 1821-6 from the Antarctic and PS1725-2 from the Arctic Ocean. The dashed lines indicate a difference of 5% between both data sets, (b) Wet bulk density logs derived from gamma ray attenuation for two 1 m long core sections of gravity core PS1725-2. Superimposed are density values measured on discrete samples. Modified after Gerland and Villinger (1995).
Fig. 2.6 Comparison of porosities and wet bulk densities measured on discrete samples and by electrical resistivities. Boyce s (1968) values for the coefficients (a) and (m) and pore fluid and grain densities of 1.024 g cm" and 2.67 g cm were used to convert formation factors into porosities and wet bulk densities. Wet and dry weights and volumes were analyzed on discrete samples, (a) Cross plots of both data sets for square barrel kastenlot core PS2178-5. The dashed lines indicate an error of 10% for the porosity and 5% for the density data, (b) Porosity and wet bulk density logs of core PS2178-5 derived from resistivity measurements. Superimposed are porosity and density values measured on discrete samples. Data from Bergmann (1996). Fig. 2.6 Comparison of porosities and wet bulk densities measured on discrete samples and by electrical resistivities. Boyce s (1968) values for the coefficients (a) and (m) and pore fluid and grain densities of 1.024 g cm" and 2.67 g cm were used to convert formation factors into porosities and wet bulk densities. Wet and dry weights and volumes were analyzed on discrete samples, (a) Cross plots of both data sets for square barrel kastenlot core PS2178-5. The dashed lines indicate an error of 10% for the porosity and 5% for the density data, (b) Porosity and wet bulk density logs of core PS2178-5 derived from resistivity measurements. Superimposed are porosity and density values measured on discrete samples. Data from Bergmann (1996).
As Hounsfield units should be related hnearly with attenuation, the calculation can be performed based on CT density values measured for the respective substance. However, as the definition of Hounsfield units implies that an attenuation of 0 is reflected by a value of -1,000 for air, the formula for the Dual-Energy Index resolves to (Eq. 5.2) ... [Pg.67]

Different density values have also been reported for PTMSP films prepared from toluene and n-hexane (d). We believe that, also in this case, the higgler density values measured for films cast from n-hexane solution can be ascribed to the better thermodynamic characteristics of this solvent. Indeed, based on results from our laboratory the solubility parameter of n-hexane, as compared to btoiuene is nearer to that ofPTMSP. [Pg.91]

With respect to experimental ethyl lactate physical properties, liquid density, refraction index and viscosity data have been measured and reported by several authors. Table 20.4.1 shows experimental ethyl lactate density values measured at atmospheric pressure and different temperatures. Table 20.4.2 presents the experimental refraction index for ethyl lactate as a function of temperature. [Pg.740]

The monolayer density, as measured by x-ray reflectivity, is only - 90% of the value of a crystalline paraffin such as suggesting a significant... [Pg.543]

The first term in Eq. (3-27) represents the voltage drop between the reference electrode over the pipeline and the pipe surface. The second term represents the potential difference AU measured at the soil surface (ground level) perpendicular (directly above) to the pipeline. Average values of the values measured to the left and right of the pipeline are to be used (see Fig. 3-24) [2]. In this way stray IR components can be eliminated. The third term comprises the current densities where, in the switched-off state of the protection installation, there is a cell current J. In the normal case J = 0 and also correspondingly AU f = 0 as well as = t/ ff On... [Pg.95]

The Thermodynamics Research Center staff have assigned an uncertainty value to each observed and recommended density value listed in the tables. The tme value of the property has a 95% probability of being in the range covered by + or - the uncertainty about the reported value. Assignment of uncertainty is a subjective evaluation based upon what is known about the measurement when the value is entered into the database, and includes the effects of all sources of experimental error. The errors have been propagated to the listed density at the reported temperature. Uncertainties reported by the investigators are considered but not necessarily adopted. Often, investigators report repeatability, but they usually do not provide uncertainty. [Pg.10]

The terms in Eq. (6) include the gravitational constant, g, the tube radius, R, the fluid viscosity, p, the solute concentration in the donor phase, C0, and the penetration depth, The density difference between the solution and solvent (ps - p0) is critical to the calculation of a. Thus, this method is dependent upon accurate measurement of density values and close temperature control, particularly when C0 represents a dilute solution. This method has been shown to be sensitive to different diffusion coefficients for various ionic species of citrate and phosphate [5], The variability of this method in terms of the coefficient of variation ranged from 19% for glycine to 2.9% for ortho-aminobenzoic acid. [Pg.107]

Densities were measured using a Paar DMA 60 meter equipped with DMA 512 and DMA 601 HP external cells. Values in the 50-150°C range were interpolated from measured data (3-5 points) values above 150°C were extrapolated and are less accurate. Interfacial tension measurements at the minimum density difference encountered (0.05 g/cm3) could be in error by as much as 10%, which is within the repeatability of measurements with heavy crude oil samples (see below). [Pg.332]

Table II summarizes surface roughness values measured for PMMA and VMCH samples etched for 1.0 minute at 35mTorr at various power densities. Although the measured values of 80 - 105 A fall within the ranges obtained from the interferometer and transition layer theory, there is no significant variation with power density. Differences in surface roughness between pre-etched films of PMMA and VMCH are also negligible according to the stylus measurements. Table II summarizes surface roughness values measured for PMMA and VMCH samples etched for 1.0 minute at 35mTorr at various power densities. Although the measured values of 80 - 105 A fall within the ranges obtained from the interferometer and transition layer theory, there is no significant variation with power density. Differences in surface roughness between pre-etched films of PMMA and VMCH are also negligible according to the stylus measurements.
Thus, there are two limitations of the pycnometric technique mentioned possible adsorption of guest molecules and a molecular sieving effect. It is noteworthy that some PSs, e.g., with a core-shell structure, can include some void volume that can be inaccessible to the guest molecules. In this case, the measured excluded volume will be the sum of the true volume of the solid phase and the volume of inaccessible pores. One should not absolutely equalize the true density and the density measured by a pycnometric technique (the pycnometric density) because of the three factors mentioned earlier. Conventionally, presenting the results of measurements one should define the conditions of a pycnometric experiment (at least the type of guest and temperature). For example, the definition p shows that the density was measured at 298 K using helium as a probe gas. Unfortunately, use of He as a pycnometric fluid is not a panacea since adsorption of He cannot be absolutely excluded by some PSs (e.g., carbons) even at 293 K (see van der Plas in Ref. [2]). Nevertheless, in most practically important cases the values of the true and pycnometric densities are very close [2,7],... [Pg.284]

Figure 19.9 shows the dependence of NaCl and NaCl03 in the 32% NaOH produced upon the current density value. A value of 3 ppm NaCl in 32% NaOH was measured as a remarkable quality of caustic soda at 7kA m-2. [Pg.257]

The volume of a substance changes with the temperature, thus affecting its density. When determining the density of a substance, the temperature should also be measured and recorded. It is generally reported along with the density value in one of the following formats ... [Pg.432]

The doping densities calculated from the slope of the C 2 versus V plots, as shown for example in Fig. 10.2, agree well with values measured by other methods [Otl]. Deviation between results obtained by spreading resistance measurements and electrochemical CV measurements are usually found to be below 20% for doping densities between 1012 and 1018 cnT3 [Pe3]. [Pg.210]

Fig. 7. Power spectrum density. The measured time series comprise several fundamental frequencies. Since frequencies have low-order (< 0.03 Hz) noise effect can be neglected. Note that if the values reference outlet substrate and the control gains decrease (experiment E.ld), then the number of fundamental frequencies in PSD decreases. This leads us to belief that there is a suitable values such that system displays hmit cycle. However, this behavior was not experimentally found. Fig. 7. Power spectrum density. The measured time series comprise several fundamental frequencies. Since frequencies have low-order (< 0.03 Hz) noise effect can be neglected. Note that if the values reference outlet substrate and the control gains decrease (experiment E.ld), then the number of fundamental frequencies in PSD decreases. This leads us to belief that there is a suitable values such that system displays hmit cycle. However, this behavior was not experimentally found.

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Density measuring

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Measured value

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