Sizing holes

Quench. Attempts have been made to model this nonisotherma1 process (32—35), but the complexity of the actual system makes quench design an art. Arrangements include straight-through, and outside-in and inside-out radial patterns (36). The optimum configuration depends on spinneret size, hole pattern, filament size, quench-chamber dimensions, take-up rate, and desired physical properties. Process continuity and final fiber properties are governed by the temperature profile and extension rate. 

Bar Length of Bolt Dimension.s Bolt size Hole Minimum Typical size of... 

Particle Size Distribntion (PSD) is the particle size fractions of the FCC cataly,st expressed as percent through a given sized hole. 

The two parts should be prepared by blowing a hole in the end of the side arm smaller than the bore of the tube and then blowing a similar sized hole in the cross-piece. These parts should next be clamped so that the tubes are nearly touching and can readily be... 

Pressure effects The diffusion through liquids is governed by the number of defects or atomic-sized holes in the liquid. A high external pressme can reduce the concentration of holes and slow diffusion. Therefore, in a liquid, a diffusion-controlled rate constant also depends on the pressure. 

Crown ethers are cyclic poly ethers and their structure permits a conformation with certain sized holes in which cations can be trapped by co-ordination with the lone... 

Can you push a quarter through a dime-sized hole in a piece of paper Take a dime and trace around it on a piece of paper. Then carefully cut out along the circle you ve drawn, leaving a hole... 

FIG. 14-118 Aerodynamic cut diameter for a single-sieve-plate scrubber as a function of hole size, hole-gas velocity, and froth density, F, g/cm3. To convert meters per second to feet per second, multiply by 3.281 to convert grams per cubic centimeter to pounds per cubic foot, multiply by 62.43. [Calvert, J. Air Pollut. Control Assoc., 24, 929 (1974).]... 

The striker is disassembled and an appropriate-sized hole drilled in the nail (the size depends on the type of solder used). The striker assembly is reassembled, with a small nail in the solder hole. 

The conductivities of Type I ionic liquids based on anhydrous zinc and iron salts tend to be lower than those of the corresponding aluminum ionic liquids. This is due largely to the higher viscosity of the former, primarily because of the large size of the ions and the availability of suitably sized holes in the ionic liquids for the ions to move into. This has been quantified by the application of hole theory as is explained in Section 2.3.4. In general imidazolium-based liquids have lower viscosities and higher conductivities than the corresponding pyridinium or quaternary ammonium eutectics formed under the same conditions. 

The conductivity of ionic liquids can be modeled in the same manner as the viscosity, i.e. despite the high ionic strength of the liquid, ionic migration is limited by the availability of suitably sized voids [130]. Since the fraction of suitably sized holes in ambient temperature ionic liquids is effectively at infinite dilution, migration should be described by a combination of the Stokes-Einstein and Nernst-Einstein equations. This is explained in greater detail in Chapter 11.3 on process scale-up but it is sufficient to say that an expression can be derived for the conductivity, k... 

Another test for determining the viscosity of liquid adhesives measures the time it takes the test liquid to flow by gravity completely out of a cup with a certain size hole in the bottom. These consistency cups are designed to expel 50 mL of sample in 30 to 100 s under controlled temperature and relative humidity conditions. The number of seconds for complete flow-out of the sample is determined. There are different cup volumes and hole sizes... 

For DBES data three main factors contribute to the S parameter in polymers (1) free-volume content, (2) free-volume size, and (3) chemical composition. First, larger free-volume content contributes to a larger S value. DBES measures radiation near 511 keV where a major contribution comes from p-Ps. This p-Ps contribution is only 1/3 the o-Ps intensity as that in I3 of PAL data. Second, when p-Ps is localized in a defect with a dimension fix, the momentum Ap has a dispersion according to the Heisenburg uncertainty principle AxAp > h/4n. The S parameter from DBES spectra is a direct measure of the quantity of momentum dispersion. In a larger size hole where Ps is localized, there will be a larger S parameter due to smaller momentum uncertainty. Therefore, in a system with defects or voids, such as polymers, the S parameter is a qualitative measure of the defect size and defect concentration. The value of the S parameter also depends on the momentum of the valence electrons, which annihilate with the positrons. The absolute value of the S parameter therefore, may differ from polymer to polymer. Third, the S parameter depends on the electron momentum of the elements. As the atomic number of the elements increases, the electron momentum increases, and thus the S parameter decreases. Fortunately, in chemicals of... 

Thermodynamics can also be used for determining of the work W, for fluctuation formation of an / -sized hole, i = 1,2,3,... being the number of amphiphile molecules that would fill the hole. Since the hole appears as a result of the passage of / molecules from the bilayer into the solution, the work associated with this process is - /A//. On the other hand, work equal to the hole total peripheral free energy /, > 0 is done in creating the hole periphery. Hence, W, is given by [399,402,403]... 

The application of an external electric field across a bilayer may also affect the bilayer stability for otherwise-stable BLMs, for example, it is known [e.g. 425,426] that an electric field can drastically shorten their lifetime. This effect arises from a decrease in the work involved in hole formation due to the application of the field. If W l is the work involved in the formation of an /-sized hole in the presence of an externally applied electric field of voltage V it has been found [e.g. 426] that... 

White phosphorus filled munitions are a major item in the current Army demilitarization inventory. Ammunition Equipment Office engineers are developing methods to punch a sized hole into the white phosphorus filled munition to control the rate at which burning occurs when the munition is processed through the deactivation furnace. By controlling the burning rate, the... 

Temple holes 2-5 sequential holes (V32-3/32 in. in diameter) in the selvedges randomly placed holes, pressure marks, or sequentially distributed pin-sized holes in the selvedges... 

Fig. 5.17. The hole model with randomly located and variable-sized holes in the liquid.

The theory of an indication of molecular-sized holes supports the idea that the model reflects some aspects of reality in liquids. How can bubbles in liquids be used as the basis of a calculation of liquid properties The answer is given by the degree to which such an approach predicts facts, for example, the compressibility (Table 5.16). The fact that it indicates the calculated size of holes seems to suggest a diffusion model in which critical acts may be the formation of the holes and the jumping into them of neighboring ions (but see Section 5.4.1). 

The theoretical basis of the transport of solute ions during iontophoresis can be compared to electrophoresis through a gel network. When the ionized solute has a mean Stokes radius smaller than the average mesh size (hole in the network), the solute is considered as a rigid sphere undergoing Brownian movement, with a mobility dependent on the frequency of solute interaction with the porous network. The sphere mobility is assumed to be proportional to the fractional volume of the pore that is accessible to the sphere [92]. The electrophoretic mobility, u, of such a solute sphere has been shown to be directly related to the molecular weight of the solute [93] ... 

The multiphcity of individually controlled air inlets is, of course, an experimental expedient. In a fully developed combustor each air inlet could be replaced by a correctly sized hole, or set of holes, to give the same volume and momentum fiux as in the experimental combustor. 

A flow device was developed with movable orifices that attempted, through the geometry of the system, to eliminate wall friction as a factor. Most consistent results were obtained when a stainless steel cylinder was used as the main hopper. The orifice was a movable end piece with different size holes. In order to select the best excipients for the direct compression of microtablets a funnel flow device, using interchangeable orifices was used. The lengths of the orifices were also varied to keep the angle of inclination constant. 

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