Effect on Flow

Free phenol is a major concern in the manufacture of novolac resins. This is true for several reasons. The strongest drivers are probably EPA classification of phenol as a Hazardous Air Pollutant and worker safety concerns. However, free phenol also has significant technical effects on such parameters as melt flow characteristics. In this role, free phenol may undermine the desired effects of a molecular weight design by increasing flow beyond the desired point. Since free phenol is often variable, the effects on flow may also cause variation in product performance from batch to batch. Fig. 18 shows the effects of free phenol on the flow across a series of molecular weights. Free phenol contents between 1 and 10% are commonly seen. In recent years, much work has been aimed at reducing the free phenol. 

For a given level of fuel at a given thickness with the same halogen content, most halogenated compounds show more or less the same flame retardancy. The key differences among these FR additives are effects on flow, melt stability, mechanical properties and long-term ageing of the FR-PBT blend. Different end-use requirements may call for the addition of different FR additives. 

Dams and reservoirs have been built in the last 100 years in vast numbers throughout many mountain areas. They serve different purposes, mainly irrigation, hydropower, water supply or flood control, or they aim at pursuing multipurpose functions. Effects on flow regime, for example shifts in summer and winter patterns, on sediment dynamics, and on other features of the aquatic ecosystems can be dramatic (cf. Sects. 2.2 in [11], this volume, 2 in [15], this volume). 

Govier and Omer, in a recent article in the Canadian Journal of Chemical Engineering, have summarized the present (G4) state of knowledge concerning the calculation of pressure drop and other quantities in two-phase flow The principal flow patterns are understood in a qualitative way and the effect on flow pattern of the major variables, mainly the lineal or maffi velocities of the phases, is recognized. In nearly all cases the real significance of the viscosities of the phases, the possible separate roles of the densities of the phases, and the influence of the diameter of the pipe is not known. 

Kosterin (K3) investigated the effect of tube inclination on flow patterns for air-water systems. As tube inclination increases, the flow patterns become more dispersed tube slope is an important variable at the lower liquid or gas rates. At high gas rates, when annular or dispersed flow normally occurs in horizontal tubes, tube inclination has little effect on flow-pattern. 

In a placebo-controlled, randomized, crossover study with 21 peri- and postmenopausal women treated for 5 weeks with a supplement delivering 80 mg total soy isoflavones/day, a significant improvement was reported in systemic arterial compliance, but had no etfect on flow-mediated vasodilation. This lack of an effect on flow-mediated vasodilation is in... 

Figure 1 shows the battery discharge effect on flow rate(3). 

When the line containing the jbursting disc is short and the disc itself has low frictional resistance after burst (total equivalent length to diameter ratio less than about 40), the friction associated with the inlet contraction from the vessel will dominate the overall frictional effect on flow capacity. Also, the critical pressure ratio can be reasonably approximated to that for a nozzle (see Annex 8, Figure A8.2). This is needed to check that flow is choked. 

Ultrasonic Effects on Flow through Porous Media... 

As previously discussed, the density of the fluid whose flow is to be measured can have a large effect on flow sensing instrumentation. The effect of density is most important when the flow sensing instrumentation is measuring gas flows, such as steam. Since the density of a gas is directly affected by temperature and pressure, any changes in either of these parameters will have a direct effect on the measured flow. Therefore, any changes in fluid temperature or pressure must be compensated for to achieve an accurate measurement of flow. 

The barrel surface exerts a retarding effect on flow rate, just as the flights in a screw extruder do. Edelist and Tadmor (45) derived the shape correction factors for Newtonian fluids, which are plotted for parallel disks as a function of H/ (Rd — Rs) in Fig. 6.32 and for wedge-shaped disks in Fig. 6.33. 

Most polysaccharides affect the mobility and structuring of water (Blanshard, 1970) beyond the immediate interface (Barfod, 1988) to a thickness of several molecular diameters (Rickayzen, 1989). The reciprocal effect on flowing polysaccharides of surface-water immobilization and structuring is a contribution to distortions from sphericity, and hence to flow birefringence. 

Vafai. K. and Tien. C.-L.. Boundary and Inertia Effects on Flow and Heat Transfer in Porous Media , Int. J. Heat Mass Transfer, Vol. 24, pp. 195-203, 1981. 

Gaseous flow has usually been investigated by theoretical means. Some experiments were also performed to verify the theoretical results. When gases are at low pressures, or are flowing in small geometries, the interaction of the gas molecules with the wall becomes as frequent as intermolecular collisions, which makes the boundaries and the molecular structure more effective on flow. This type of flow is known as rarefied gas flow. 

Effect of Emulsion Characteristics. As discussed in Chapter 4, the rheology of emulsions is affected by several factors, including the dis-persed-phase volume fraction, droplet size distribution, viscosity of the continuous and dispersed phases, and the nature and amount of emulsifying surfactant present. All of these parameters would be expected to have some effect on flow behavior of the emulsion in porous media. However, the relationship between bulk rheological properties of an emulsion and its flow behavior in porous media is feeble at best because, in most cases, the volume... 

In each case, preconditioned material was placed in the hopper of an instrumented tablet machine and the performance of these two materials was compared at constant machine settings. The sample with 5.1% MC produced tablets that weighed slightly less (an effect on flow and bulk density), and as a result were exposed to lower compression force. However, the moist microcrystalline cellulose resulted in harder tablets, even though it had been exposed to lower compression force. The loci of points on the compression force versus hardness profile (Fig. 20) for the tablets indicate a different fundamental behavior for the two materials. 

In the medium pressure range (1-10 bar) the is almost always above 4000 and below 400,000, so its effect on flow pattern is almost nonexistent, and consequently, it has a minor effect on dimensionless flow characteristics. If the valve range is truly geometrically similar, then the discharge coefficient will be unaffected... 

Lakatos., I., Lakatos-Szabo, J., Toth, J., 1979. Eactors influencing polyacrylamide adsorption in porous media and their effect on flow behavior, Paper presented at the Symposium on Surface Phenomena in EOR, Stockholm, August, Plenum. 

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