Cross-sectional surface area

For low purity hydrocarbon fraction, the number of drip or separate flow points shoitid be 6-10 drip points/ft of tower cross-section surface area. 

The velocity of blood flow through capillaries is slow compared to the rest of the circulatory system because of the very large total cross-sectional surface area of the capillaries. Although each individual capillary has a diameter of... 

The cross-sectional surface area of the N2 molecule at 77 K, assuming that it is packed like a liquid on the surface of the adsorbent, is Am = 0.167 nm2. But the cross-sectional surface area of a given adsorptive may not be constant, because it depends somewhat on the nature of the adsorbent, and the conventional picture of an Am value for a monolayer completely filled with adsorbate molecules in a liquid-like packing does not correspond to the physical reality. This is evident since anomalous results (significantly different values) have been obtained when the surface area of a given solid was obtained from the adsorption isotherms of different adsorbates [4,7],... 

In the equations above a is the true tensile stress, i.e. F/A. In practice in general use is made of engineering stress, which is equal to F/Aa, where F is the tensile load and A and A0 are the cross-sectional surface areas of the sample in the deformed and non-deformed state, respectively. Because the Poisson constant Vi for rubbers A = A0/A, so that the equations for the tensile stress become ... 

Flux (7) of a species is the mass (M) (or number of molecules of this species) transported per unit time across the barrier, normalized by the cross-sectional surface area A of the barrier ... 

Miller, L., Banson, F.L., Bazir, K., Korimilli, A., Liu, J.B., Dewan, R., Wolfson, M, Panganamamula, K.V., Carrasquillo, J., Schwartz, J., Chaker, A.E., Black, M. Risk of esophageal variceal bleeding based on endoscopic ultrasound evaluation of the sum of esophageal variceal cross-sectional surface area. Amer. J. Gastroenterol. 2003 98 454-459... 

Figure 18.2 Cost of a chromatographic column skid versus the cross-sectional surface area of the column. Reproduced with permission from A. Katti, in Handbook of Analytical Separations, Vol. 1, "Separation Methods in Drug Synthesis and Purification," K. Valko, Ed., Elsevier, Amsterdam, The Netherlands, 2000, p. 213 (Fig. 7.7).

Reduction ratio, the ratio of the cross sectional surface areas of the preform and the extrudate, is an important variable in paste extrusion. For a given extruder barrel, the smaller the cross section of the final product, the higher the reduction ratio. The size of the preform can be varied in a fairly limited range, therefore, resins must be able to undergo the reduction during extmsion. Different fine powder grades have been developed by suppliers to accommodate the wide range of reduction ratios of commercial operations. 

Reduction Ratio - This factor is the ratio of cross-sectional surface areas of the preform and the extrudate in paste extrusion. Different dispersion polymerized polytetrafluoroethylene powders accommodate different reduction ratio ranges. In general, reduction ratio of the resin decreases as molecular weight increases. Melt fracture and defects appear in the extrudate if it is processed at above its maximum reduction ratio. 

C2 is the cross-sectional surface area shape factor, n(Z) is the particulate size distribution function dN/dl, and Kext is the extinction eflBciency (a function of A., the wavelength of the incident light, I, the particulate size, and m, the particulate refractive index relative to the surrounding medium). Thus, the contribution of any given size fraction of the distribution to the extinction coeflBcient is partly a function of the size frequency distribution as shown by the expression... 

Answer Boundary condition (1) in the solution to part (e) indicates that there is no flow through a point on the symmetry axis at r = 0. In other words, if both ends of a vector lie on this centerline, then no cross-sectional surface area results from a 360° rotation of this vector around the symmetry axis. Hence, the volumetric flow rate Q and the stream function if vanish at r = 0. One concludes that A = C = 0 and... 

Nonetheless, an initial difficulty may arise with respect to the correct assessment of the cross-sectional surface area of the adsorbate molecule, which also depends on the adsorbate-adsorbent interaction since this can change the orientation of the adsorbed molecules. Often, the adsorbed molecule occupies not only the site on the surface, but also some neighboring volume, thus creating steric difficulties for the adsorption of other molecules and leading to a possible underestimation of the monolayer capacity [20], Moreover, in the case of some specific interactions, e.g. associative interactions, the stiucture of the adsorbed layer may change as an effect of adsorbate-adsorbate interactions. Under these circumstances, it may be useful to refer to appropriate literature data for cd [9],... 

The amount of active substance applied to the eye depends not only on the concentration but also on the drop size, which is influenced by the surface tension of the solution. The design, dimensions of the dropper tip, the cross-sectional surface area on which the drop is formed and the dispensing angle at which the patient manipulates the bottle influence the drop volume instilled [43]. 

Second, when a solid having an initial cross-sectional surface area A, measured at a reference temperature r , is heated to a final temperature T, it exhibits a final cross-sectional surface area A > A . The relative increase of cross-section AA/A is directly proportional to... 

Consider first the case of confined cylindrical channels. This was the first configuration studied. Lucas, Washburn and Rideal gave a non-inertial solution as early as 1921 [7-9]. In (1.46), the value of A can be determined by considering the value of the hydraulic resistance per unit length =S/Ijthe wetted perimeter = 2 nR, and the cross-sectional surface area and using (1.45). One obtains A = Rf 4. After substitut-... 

Cross-sectional surface area of nm 0.34 Swarup, S Nigam, A N, J. Appl. 

In the model of the representative layer that we present here, each particle type is characterized by its composition, volume, and the average cross-sectional surface area that it presents to the incident beam. We will picture a particle as having two flat ends, each perpendicular to the incident beam. While the shape of the cross section is not important for our model, it may be pictured as a square. 

For all particle types, the cross-sectional surface area in the layer is in the same proportion as the surface area of the particle type in the sample as a whole. 

The fraction of the cross-sectional surface area that is made up of voids is the same as the void fraction of the sample as a whole. 

The absorption is a property of a molecule and can be well represented as a continuum, but remission is a property of an interface and may not be well represented as a continuum. In the absence of absorption, the remission is independent of the thickness of a layer. The remission fraction from a single representative layer is dependent only on the fraction of the cross-sectional surface area occupied by each type of particle and the remission power of the material of which the particle is composed. In the presence of absorption, the remission fraction diminishes (causing a reduction in the remission coefficient). 

The contribution of a particle type to remission is proportional to the total cross-sectional surface area of the particle type in the representative layer and the remission power of the material making up the particle. 

An interesting scale-up technique exists for centrifuges. Essentially, it indirectly compares a given centrifuge to a settling tank that will perform the same function. This is done by using the cross-sectional surface area, of such a settling tank. The... 

The specific surface area of a powder is conveniently determined through a Brunauer-Emmett-Teller (BET) analysis. Here, the adsorption of nitrogen is determined and then analysed. Since the cross-sectional surface area of a nitrogen molecule is known, the total area of a powder sample can therefore be determined. BET analysis is conveniently carried out by using commercial instruments build solely for this purpose. In some cases, the solid sample cannot be treated (dried) to give a dry powder. In such cases, the specific surface area can be determined by the adsorption of a surfactant, with a known cross-sectional surface area, that adsorbs as a monolayer at that specific surface. This method is, of course, rather uncertain since it requires the assumption of monolayer adsorption. 

Consistently, the cross-sectional surface area occupied by the SAN chain at the interface (A) was calculated for samples with an average particle size of 0.4 pm and found to increase with the RGC of SAN-NH2, whereas A did not change with the RGC of... 

Table 4.1 Calculated Cross-Sectional Surface Area per Bound SAN Chain (A) and Experimental Impact Strength (in Brackets) vs. the NH2(carb)/MA Molar Ratio...

Cross-sectional surface area per bound SAN chain (nm )... 

The mass flow rate of the engine being rhS, and with m being the unit mass flow rate of propellant and S the cross-sectional surface area of the engine outlet, the thrust of the rocket is given by the momentum balance T = mS g, with the ejection velocity of the propellant in relation to the body of the rocket. The specific impulse is equal to the thrust provided per unit weight of propellant consumed (and therefore ejected) ... 

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