Bulk density measurements

The bulk density measured by the logging tool is the weighted average of the rock matrix and fluid densities, so that ... 

Stmcture is usually measured by a void volume test such as the absorption of dibutyl phthalate (DBPA) (15), or by bulk density measurements of the carbon black under compression. In order to eliminate the effects of pelletizing conditions the DBPA test has been modified to use a sample that has been precompressed at a pressure of 165 MPa (24,000 psi) and then broken up four successive times (24M4) (16). This procedure causes some aggregate breakdown and is claimed to more closely approximate the actual breakdown that occurs duting mbber mixing. 

A key factor in the suitabihty of cokes for graphite production is their isotropy as determined by the coefficient of thermal expansion. After the calcined coke was manufactured into graphite, the axial CTE values of the graphite test bars were determined using a capacitance bridge method over a temperature range of 25 to 100°C. The results are summarized in Table 24. Also included in the table are bulk density measurement of calcined cokes and the resistivity values of their graphites. 

Tap density (ptap) is an extension of bulk density measurements, and the procedure used to measure the tap density again varies from lab to lab and can affect the final results. To measure tap density, a graduated cylinder is filled with powder and the weight and volume are recorded. The difference observed between procedures is the number of taps used for the measurement. In some cases, a particular number of taps is used, such as 200 [65], 500 [66], or even 1000 taps [67]. Other procedures involve tapping the cylinder for a number of times, recording the volume, and repeating the procedure until the volume remains constant [68]. This method ensures more consistent results. 

The compressibility of a material can be estimated from the tap and bulk density measurements [69] ... 

A number of issues relative to the prediction of solids conveying in smooth bore single-screw extruders are exposed from the theoretical fits to the data in Fig. 5.32. First, the data needed to carry out an effective simulation is difficult to take and is very time consuming, and only a few labs have the proper equipment that is, bulk density measurement, dynamic friction data, lateral stress, and solids conveying data. Moreover, care must be taken to develop an accurate representation of the surface temperature for the barrel and screw as a function of the axial position. This would be quite difficult in a traditional extruder with only a control thermocouple to measure the temperature at the midpoint of the barrel thickness. Second... 

The method of product porosity measurement depended on the size of product particles. The porosity of granules for the size fraction dg < 4 mm was determined on the basis of bulk density measurement. The porosity of granules from a given size fraction was calculated from the formula... 

In addition to expressing soil C stocks on an areal basis, it may be preferable, particularly for comparisons of C stocks due to land use changes that alter bulk density, to express soil C stocks on an equivalent mass basis. This approach, nicely explained by Ellert et al. (2001), samples to a depth giving a constant mass of soil at all locations or time points, rather than a constant depth of soil. Calculating the required depth requires bulk density measurements. 

There are several new in situ soil carbon measurement techniques undergoing field testing. Some devices, such as those using a neutron generator, measure total C atoms to a known depth, and as a result do not require a bulk density measurement (L. Wielopolski, personal communication, March 2007). In addition, such in situ and noninvasive techniques would allow the same location to be measured repeatedly. However, for the time being, and likely for many applications in the future, the importance of carefully measuring bulk density cannot be overstated. 

In conclusion, definite information on the density of adsorbed interlayer water cannot be derived from the bulk density measurements. However, such measurements supplement adsorption isotherm data, and both will be helpful in the interpretation of x-ray structure analysis of the configuration of water molecules and exchange cations in the interlayer space. 

Powder properties Bulk density measurement Determine Carr s index... 

Bulk density (Dj,) is defined as the mass (weight) of a rmit volume of diy soil. This volume includes both solid and pores. The values for clay, clay loam and silt loam surface soils varies from 1.00 - 1.60 g/cm, for sand and sandy loams from 1.20 - 1.80 g/cm. Fine - texture soils tend to have lower bulk densities and therefore higher porosities in comparison to the coarse textured soils due to loose packing of the clay particles. Bulk density measurement for soils is important since it determines the degree of compactness as a measure for soil structure and is used for calculating pore space of soils. 

The general use of soil pits means that samples and bulk density measurements are usually made horizontally into the pit wall at the mid-point of the sample interval, rather than by collecting the whole depth interval this can potentially introduce (smaller) biases if the distribution of carbon with depth is not uniform. In addition, there is little uniformity in the literature with regard to whether samples are sieved or not, and whether/how soil carbonate is considered. 

Porosity and wet bulk density are closely related, and often porosity values are derived from wet bulk density measurements and vice versa. Basic assumption for this approach is a two-component model for the sediment with uniform grain and pore fluid densities (p ) and (p, ). The wet bulk density can then be calculated using the porosity as a weighing factor... 

A detailed comparison of both data sets is shown in Figure 2.4b for two segments of core PS 1725-2. Wet bulk densities measured on discrete samples agree very well with the density log derived from gamma ray attenuation. Additionally,... 

Fig. 2.5 Influence of an iterative mass attenuation coefficient determination on the precision of wet bulk densities. The gamma ray attenuation log of gravity core PS 1725-2 was used as test data set. (a) Wet bulk densities calculated with a constant mass attenuation coefficient ( processing porosity =50%) are displayed versus the data resulting from die iteration. A pore fluid density of 1.024 g cm and a constant grain density of 2.7 g cm were used, and the iteration was stopped if densities of two successive steps differed by less than 0.1%o (b) Cross plot of wet bulk densities measured on discrete samples versus wet bulk densities calculated from gamma ray attenuation with a constant mass attenuation coefficient (O) and with the iterative scheme (+). (c) Influence of grain density on iteration. Three grain densities of 2.65, 2.75 and 2.1 g cm were used to calculate wet bulk densities. Modified after Gerland (1993).

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).

Bulk density is determined by weiring a container, of a known volume, that is filled level-full with the sample. There are two types of bulk density measurements - loose pour and tapped. ... 

Although more labor-intensive and less efficient, information on the densification kinetics and densification can also be obtained from density measurements on different individual samples as a function of time for otherwise identical sintering conditions. Bulk density measurements on <92% dense sintered samples containing open porosity can be determined from the measured mass and dimensions of the compact, while Archimedes method works well for closed pore, >92% dense bodies. The density of closed pore samples can also be determined by pycnome-try (e.g., helium pycnometry),, 37 mercury porosimetry, and by the sink-float method (i.e., whereby the buoyancy of the sample is assessed and compared in different density liquids). Density can also be estimated from micrographs using quantitative stereology. 

A serious limitation of the Hausner ratio is the elimination of any consideration of bulk density in the final calculation. As discussed below, two materials with similar Hausner ratios but different densities are likely to behave much differently in practice. Finally, it has been shown that tapped bulk density measurements are extremely sensitive to the apparatus being used and the number of taps. Standardization of these factors is necessary to ensure consistent and comparable results. 

Figure 5 Transition energy of phenol blue in SC 1,1-difluoroethane as a function of the bulk density. Measured values (symbols) and values expected on the basis of the dielectric constant of the bulk fluid (line) reprinted from Ref. 15...

Bulk density Measurement of the apparent density of a given material such as grains or processed products. It is named bulk because it measures the product weight contained in a certain volume that includes air spaces. 

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