Vertical rods

For a vertical rod anode, the general formula comparable with Eq. (24-21) is given by ... 

BIO. Becker, K. M., A correlation for burn-out predictions in vertical rod bundles, paper presented at Symp. Boiling and Two-Phase Flow, EURATOM, ISPRA, June 1966. 

Venkateswararao et al. (1982), in evaluating the flow pattern transition for two-phase flow in a vertical rod bundle, suggested the calculation of pressure gradient for annular flow by... 

Becker, K. M., 1963, Burnout Conditions for Flow of Boiling Water in Vertical Rod Clusters, AIChE J. 9 216-222. (5)... 

Another well-known phenomenon is the Weissenberg effect, which occurs when a long vertical rod is rotated in a viscoelastic liquid. Again, the shearing generates a tension along the streamlines, which are circles centred on the axis of the rod. The only way in which the liquid can respond is to flow inwards and it therefore climbs up the rod until the hydrostatic head balances the force due to the normal stresses. 

The vertical rod method of the preceding problem was used to study the contact angle of water at the gold-water-air junction at 25°C. The following data show how the value of 0a depends on the prior history of the metal surface. For a gold surface polished, washed, and heat treated for 1 hr at T°C, then allowed to stand in air for t hr we obtain... 

Figure A.5 Ewald construction for surface diffraction, a) a side view of the reciprocal lattice at the surface. Constructive interference occurs for all intersection points of the vertical rods with the Ewald sphere. This is equivalent to the condition when the component qj of the scattering vector parallel to the surface is identical to a reciprocal lattice vector of the surface lattice, b) the top view of the reciprocal surface lattice. The circle is the projection of the Ewald sphere. If we disregarding the radiation scattered into the crystal, the number of lattice points within the circle (corresponding to the intersections of the rods with the Ewald sphere) is identical to the maximum number of observed diffraction peaks.

Viscoelastic fluids have elastic properties in addition to their viscous properties. When under shear, such fluids exhibit a normal stress in addition to a shear stress. For example, if a vertical rod is partly immersed and rotated in a non-viscoelastic liquid the rod s rotation will create a centrifugal force that drives liquid outwards toward the container walls, as shown in Figure 6.16(a). If, on the other hand, the liquid is viscoelastic then as the liquid is sheared about the rod s axis of rotation, a stress normal to the plane of rotation is created which tends to draw fluid in towards the centre. At some rotational speed, the normal force will exceed the centrifugal force and liquid is drawn towards and up along the rod see Figure 6.16(b). This is called the Weissenberg effect. Viscoelastic fluids flow when stress is applied, but some of their deformation is recovered when the stress is removed [381]. 

It is common in corrosion laboratories and in field corrosion monitoring probes to immerse two vertical rods parallel to one another in an electrolyte. In the lab, one of the rods consists of a high-density graphite counterelectrode while the other is a working electrode. A reference electrode may be placed in between the two rods. In the field, polarization resistance or electrochemical noise measurements are often made between two nominally identical rods that both consist of the material of interest. The primary current distribution is nonuniform with respect to circumferential position about each electrode when the distance between the two rods is small in comparison to the radius of the rod, Fig. 10a (16). Again, the value of Ra varies from where the rods face each other to where they... 

Zone refining a modem method of refining where a narrow ring furnace melts a thin disk in a vertical rod of impure material under an inert atmosphere. Impurities are more soluble in the melt, and as the ring furnace traverses the rod the impurities are swept to the end for eventual discard. The process may be repeated until the desired degree of purity has been achieved... 

In all these approaches the weight of the object plus the adhering fluid is measured. Basically the inverse process in which the weight of the liquid is measured is also possible, by placing the vessel with liquid on a sensitive toploading anal3dical balance. Christian et al. ) proved the viability of this concept for the pulling-out of a vertical rod ( Padday s pencil, see sec. 1.8c). 

The reader may note that the far-field hydrodynamic interactions cause the vertical configuration to sediment slightly faster than the horizontal configuration. This is qualitatively similar to the fact that a vertical rod falls faster than the same rod in a horizontal orientation [see equations (8-191) and (8-193)]. 

The U-235 chain reaction is harnessed for commercial power as illustrated in this model of a nuclear-electric power plant near Chicago. Enclosed in concrete beneath the upper crane is the uranium reactor with its vertical rods which are the fuel elements. 

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