Bore fluid

The relationship between the bore fluid pressure drop, AP and its flow rate is defined by Poiseuike s law ... 

Fiber dimensions have been studied for hemodialysis. When blood is circulated through the fiber lumen (m vivo), a significant reduction in apparent blood viscosity may occur if the flow-path diameter is below 100 p.m (11). Therefore, current dialy2ers use fibers with internal diameters of 180—250 p.m to obtain the maximum surface area within a safe range (see Dialysis). The relationship between the fiber cross section and the blood cells is shown in Figure 5. In many industrial appUcations, where the bore fluid is dialy2ed under elevated pressure (>200 kPa or 2 atm), fibers may burst at points of imperfection. Failure of this nature is especially likely for asymmetric fibers that display a large number of macro voids within the walls. 

N. Monfreux, P. Perrin, F. Lafuma, and C. Sawdon. Invertible emulsions stabilised by amphiphilic polymers and application to bore fluids (emulsions inversables stabilisees par des polymeres amphiphiles et application a des fluides de forage). Patent WO 0031154, 2000. 

Both floating and trunnion-mounted designs are available with other design variations that include metal seied valves, soft seated valves, top-entry valves, end-entry valves, and split body valves. Valves in all these design variations are available as either full port or reduced port. Port refers to the round-bore fluid flow area through the ball. Full port valves have a bore that is approximately equal to the inside diameter of the mating pipe. Reduced port valves have a bore that is approximately equal to the inside diameter of pipe one size smaller than full bore. 

Figure 3.35 Depending on the bore fluid and the composition of the coagulation bath, the selective skin layer can be formed on the inside, the outside or both sides of the hollow fiber membrane...

Casting dope Bore fluid Precipitation bath Membrane type... 

There are many methods by which well-bore fluids can be raised to the platform or land level. In situations where high flow rates are required, the main options are -... 

Y. Su, G.G. Lipscomb, H. Balasubramanian, and D.R. Lloyd, Theoretical Observations of Recirculation Regions in the Bore Fluid during Hollow Fiber Spinning, AIChEJ, 52 (2006) 2072-2078. 

Feng et al. [32] studied the morphology of the inner and outer surfaces of hollow fibers fabricated from poly(etherimide) by TM-AFM. The hollow fibers were fabricated by the dry-wet phase inversion method at two different bore fluid flow rates, 0.1 and 0.4 mLmin and their effect on the surface morphology was investigated. The average pore sizes on the inner surface were 39.8 and 81.9 nm, respectively, for 0.1 and 0.4 mLmin while those on the outer surface were 218.4 and 93.4, respectively, for 0.1 and 0.4 mLmin h It is interesting to note that the pore size increased with an increase in the bore fluid flow rate at the inner surface, while the opposite was the case at the outer surface. 

The first observation mutually confirms the nodules sizes observed either by SEM or by AFM. The second observation is expected because the coagulation of the polymer occurs soon after the extrusion of the casting dope from the spinneret, when it is brought into contact with the bore fluid (water). The third observation is similar to the result obtained by Fujii et al. [13] for their PAN hollow fiber, in which the mean diameters of the nodules, called spheres in their paper, are reported at the area near the inner surface, in the middle section, and at the area near the outer surface to be 118.0,166.0, and 109.0 nm, respectively. The fourth observation is probably due to the stretching of the outer surface that occurs while the hollow fiber is traveling through the air gap. 

In flat sheet membranes, the nodules/nodule aggregates observed in the cross section are aligned parallel to the surface-forming layers. In hollow fibers, the aUgnment of the nodules was observed in the angular direction. In hollow fiber formation, the rate of the bore fluid influences the alignment of the nodules. 

Bore fluid Mean surface PWP PEO separation (%) Pore size, dia-... 

The general process for preparation of the precursors consists of four steps, i.e. dope formation, casting/spinning, dehydration and post-treatment. There are many parameters that will affect the precursor properties during the preparation process. An example for the optimization of spinning condition was reported by He et al., who reported that the optimal conditions for spinning cellulose acetate hollow fiber membranes was found to be as follows bore fluid, water+ NMP (85%) air gap 25 mm bore flow rate, 40% of dope flow rate (2.2 mL min ) and temperature of quench bath, 50... 

Jian and Pintauro (1997) used asymmetric PVDF hfs for organic-water PV separations. They reported that organic-water separation properties depend on the spinning solution viscosity and bore fluid composition. Variations in the membrane performance (benzene separation factor and flux) with the changes in organic-feed concentration, downstream pressure, and feed temperature were qualitatively similar to those observed for flat sheet asymmetric PVDF membranes and elastomeric PV membranes. 

Tan, X., Liu, N., Mengand, B. and Liu, S. (2011) Morphology control of the perovskite hollow fibre membranes for oxygen separation using different bore fluids. Journal of Membrane Science, 378, 308-318. 

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