Measurement effective diameter

The fimctiong(ri is central to the modem theory of liquids, since it can be measured experimentally using neutron or x-ray diffraction and can be related to the interparticle potential energy. Experimental data [1] for two liquids, water and argon (iso-electronic with water) are shown in figure A2.4.1 plotted as a fiinction ofR = R /a, where a is the effective diameter of the species, and is roughly the position of the first maximum in g (R). For water, a = 2.82 A,... 

Many particles are not spherical and so will not have the same drag properties as spherical particles. The effective diameter for such particles is often characterized by the equivalent Stokes diameter, which is the diameter of the sphere that has the same terminal velocity as the particle. This can be determined from a direct measurement of the settling rate of the... 

The initial momentum of the jet must also be considered, as it is significant. An effective nozzle diameter can be determined to account for this momentum since sprinkler discharges lose momentum when they strike the droplet dispersal plate. This effective diameter can be found by measuring the initial thrust (Fa) of the spray. Consequently, another group follows as... 

The data were plotted, as shown in Fig. 11, using the effective diameter of Eq. (50) as the characteristic length. For fully turbulent flow, the liquid and gas data join, although the two types of systems differ at lower Reynolds numbers. Rough estimates of radial dispersion coefficients from a random-walk theory to be discussed later also agree with the experimental data. There is not as much scatter in the data as there was with the axial data. This is probably partly due to the fact that a steady flow of tracer is quite easy to obtain experimentally, and so there were no gross injection difficulties as were present with the inputs used for axial dispersion coefficient measurement. In addition, end-effect errors are much smaller for radial measurements (B14). Thus, more experimentation needs to be done mainly in the range of low flow rates. 

Oda, T., Makino, K., Yamashita, I., Namba, K., and Maeda, Y. (1998). Effect of the length and effective diameter of F-actin on the filament orientation in liquid crystalline sols measured by X-ray fiber diffraction. Biophys. J. 75, 2672-2681. 

At 15°C the viscosity of water is 0.0114 g cm-1 s (poises), and the measured diffusion coefficient for glucose in water is 0.52 x 10"5 cm2/s. What is the friction coefficient / What is the effective diameter of the glucose molecule, assuming that it behaves as a spherical particle in a continuous medium ... 

Fairs (1943) has criticized the method of linear measurements above described. He points out that the diameter so measured does not correspond with the Stokes or effective diameter det but is usually greater. The importance of avoiding some shape factor to convert d to de is obvious but over and above this lies the fact that a linear measure is of statistical interest only, as already inferred. A diameter to be useful must be related to measures of mass or surface. Schweyer (1942) in his comprehensive analysis of particle size techniques (about which more will be said later) has dealt with this subject in detail. 

The microscopic method was used in only one set of experiments, viz., for a material whose median effective diameter was 25 /x. Good agreement was found between pipette, hydrometer, and microscopic methods for sizes ranging from 25 to the upper limit of the experiment, 100 ix. Below 25 ix, both sedimentation methods gave similar results, but there was a marked difference with the microscopic method. Thus, at 10 ix, the percent found undersize by the sedimentation methods was 25 percent and that found undersize by the microscopic method was 12 percent. This difference can be attributed in part to difficulties in preparing samples for measurement, but undoubtedly the failure to commute shape factors can be regarded as the chief source of divergencies. 

We have seen that electron microscopy and scanning probe microscopies are very complementary techniques to characterize the structure and the morphology of supported clusters. The internal structure can only be resolved by HRTEM while the surface atomic structure can be only revealed by STM or AFM. TEM gives accurate diameter measurements and height can only be measured in profile view that needs special sample preparation. STM or AFM give accurate height measurements but diameters can be obtained only after correction from the tip-sample convolution effect. 

Spacings are from 6.35 to 31.75 mm (in 6.35 mm increments) with 9.5 mm the most common. Stud densities are 60 x 60 to 110 x 110 mm, the former the most common. The width (measured to the spiral flow passage), is from 150 to 2500 mm (in 150 mm increments). By varying the spacing and the width, separately for each fluid, velocities can be maintained at optimum rates to reduce fouling tendencies or utilize the allowable pressure drop most effectively. Diameters can reach 1500 mm. The total surface areas exceed 465 sqm. Materials that work harder are not suitable for spirals since hot-forming is not possible and heat treatment after forming is impractical. 

Effective density. The diameter and volume of the micropores were determined by the measurement of the density using as displacement molecules with different sizes of effective diameter, e g., helium (0.25 nm), water (0.264 nm), benzene (0.370 x 0.528 nm), and decaline (0.472 X 1.01 X 0.624 nm). All pycnometric fluids are non-polar, except water. This adsorbate was used for the sake of the little diameter of its molecule. In the case of CMSs studied - not including of oxygen surface groups [8] - water molecule is good molecular probe. 

Note (1) Average effective diameter measured by light scattering. 

In flow through a tube, therefore, the measured effective viscosity, which is defined to be proportional to the pressure drop, depends on the Ericksen number. Note that the Ericksen number is proportional to Vh, the velocity times the tube diameter, where we take h = 2R. Since the velocity V is proportional to QfR, Vh is proportional to Q/R. Thus, the data for various tube radii in Fig. 10-11a collapse onto a single line when plotted against AQfjtR (see Fig. 10-1 lb). This shows that the effective viscosity is a function of the Ericksen number, which is proportional to the velocity times the tube diameter. (For shear-thinning isotropic liquids, on the other hand, the viscosity depends on y ff, which is the velocity divided by the tube diameter.) Because of the orientation-dependence of the viscosity (illustrated in Fig. 10-9a), the wall layer is much more viscous than the core fluid and since the thickness 5 of the wall layer scales as it follows... 

Figure 10.47 shows for the % in. inside diameter mixer reactor the importance of the initial molar feed ratio. For relatively low initial molar feed ratios (below about 1.0) the recycle loop/static mixer system can actually give poorer performance than the agitated vessel without a recycle loop. The data indicate that this ratio should be kept above 3 to ensure that the recycle loop/static mixer system is used to fullest advantage. At recycle ratios of 2.4, the feedpipe velocity had a minor, although measurable, effect on the yield of the slowest reaction. 

A cytostatic effect will result in a reduction in the number of cell doublings in a given time and thus a reduction in the number of cells within a colony. There are several ways of quantifying a cytostatic effect. The most direct method is to count the number of cells in 50 representative colonies per dish. Alternatively, it can be estimated by measuring the diameter of the colony and thus calculating the area of the colony. This method assumes that there is no change in cell size. 

This wavelength is far too short to give any measurable effects. Recall that atomic diameters are in the order of 10-2° rn, which is 24 powers of 10 greater than the baseball wavelength. ... 

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