Concentric rings

Lin et al. [70, 71] have modeled the effect of surface roughness on the dependence of contact angles on drop size. Using two geometric models, concentric rings of cones and concentric conical crevices, they find that the effects of roughness may obscure the influence of line tension on the drop size variation of contact angle. Conversely, the presence of line tension may account for some of the drop size dependence of measured hysteresis. 

Microscope appearance. Place a small amount of dry starch on a microscope slide, add a drop of water, cover with a slip and examine under the microscope. Characteristic oval grains are seen which have concentric rings round a hilum which is towards one end of the grain. Run a drop of very dilute iodine solution under the slip from a fine dropping-tube the grains become blue. 

Figure 9.20 (a) Stimulated Raman scattering experiment, (b) Concentric rings observed, in the... 

Polytetrafluoroethylene (PTFE) provides the most satisfactory electrical insulation. Concentric rings of PTFE and PTFE impregnated with calcium fluoride are used for the packing glands which support the anode and cathode posts. Rubber is used as the gasket material to form a seal between the cover... 

Fig. 2. Gas-fired denitration pots for denitration of U02(N02)2 6H20. (a) The large pot (1.68 M ID, 0.81 m height) is heated by three concentric rings of small radiant gas burners, (b) The small pot (76 cm ID, 46 cm height) is heated by four gas burners iaside a ceramic furnace (40).

When both solids and gases pass through the distributor, such as in catalytic-cracldng units, a number of variations are or have been used, such as concentric rings in the same plane, with the annuli open (Fig. 17-9a) concentric rings in the form of a cone (Fig. 17-9b) grids of T bars or other structural shapes (Fig. 17-9c) flat metal perforated plates supported or reinforced with structural members (Fig. 17-9d) dished and perforated plates concave both upward and downward (Fig. 17-9e and f). The last two forms are generally more economical. 

The graphical integration method is based on graphical presentation of the average flow profile. For a circular duct, the cross-section is virtually divided into several concentric ring elements. The spatial mean velocity of such an element is determined as an arithmetical mean of local velocities along the circumference of the corresponding radius. For a circular cross-section the flow rate can be expressed as... 

In the arithmetical methods a circular flow cross-section is divided into concentric rings and a central element. The areas of the elements are equal except for the outermost ring, which has only half of that area, A hypothesis is made for the velocity profile for each element. For example the log-linear rule assumes a velocity profile of... 

An important principle is that security must be built in depth - otherwise known as defense in depth. In this context, it may be helpful to think of security as a set of concentric rings, where the target is located at the center. Each ring represents a level of physical protection (perimeter fence, building shell, security case) but the number of rings and security resistance will vary relative to the risk. The spaces between the rings may represent other defensive measures such as closed-circuit television (CCTV), security lighting, intruder alarm systems, etc. 

Feitknecht has examined the corrosion products of zinc in sodium chloride solutions in detail. The compound on the inactive areas was found to be mainly zinc oxide. When the concentration of sodium chloride was greater than 0-1 M, basic zinc chlorides were found on the corroded parts. At lower concentrations a loose powdery form of a crystalline zinc hydroxide appeared. A close examination of the corroded areas revealed craters which appeared to contain alternate layers and concentric rings of basic chlorides and hydroxides. Two basic zinc chlorides were identified, namely 6Zn(OH)2 -ZnClj and 4Zn(OH)2 ZnCl. These basic salts, and the crystalline zinc hydroxides, were found to have layer structures similar in general to the layer structure attributed to the basic zinc carbonate which forms dense adherent films and appears to play such an important role in the corrosion resistance of zinc against the atmosphere. The presence of different reaction products in the actual corroded areas leads to the view that, in addition to action between the major anodic and cathodic areas as a whole, there is also a local interaction between smaller anodic and cathodic elements. 

Moreover, Thomson considered that the electrons rotated within the positive charge in the form of concentric rings, an idea which he adopted on reading about Alfred Meyer s... 

X-rays. The diffraction from this polycrystalline and disoriented fiber is the sum of the diffraction from all the randomly oriented microcrystallites, and it corresponds to a series of concentric rings, each with its characteristic (/-spacing. The intensity is uniform on a ring, but it varies among rings. This type of diffraction, commonly referred to as a powder pattern, is prevalent among minerals and polymers that have a low degree of polymerization. 

Fic. 2. (continued)—(b) an assembly of randomly oriented microcrystallites (left) diffracts to produce a series of concentric rings (right) (c) an assembly of partially oriented blocks of microcrystallites (left) diffracts to produce large arcs (right). 

Fig 6 Immunodot-blots of culture-medium aliquots sampled during the time-course of differentiation of Zinnia mesophyll cells to tracheary elements and dotted on to nitrocellulose. I = Inductive medium, N = Non-inductive medium. The JIM 7 epitope dries in a series of concentric rings on the nitrocellulose, indicating a mixed population of pectins. During the time-course, the rhamnose content of inductive culture medium increases dramatically compared with non-inductive medium. 

If the position of sample application and the point of entry of the mobile phase are at the center of the plate and the flow of mobile phase is towards the periphery of the plate, then this node of development is called circular chromatography [6,110]. Samples can be injected into the mobile phase, in which case they will be separated as a series of concentric rings. If the samples are applied as a cluster of spots in a radial pattern around the solvent entry position, after development, spots near the origin remain symmetrical and compact trtiile those near the solvent front are compressed in the direction of development and elongated at right angles to this direction. Figure 7.10(A). 

Around the wedge are drilled a number of holes known as easers, arranged in approximately concentric rings. The detonators used in these holes have delays which gradually increase in number as the hole is farther from the wedge. This is to ensure that the inner holes nearest the free face always fire first and can produce a fresh free face against which the farther shots can work. Finally, an outer row of holes, known as trimmers, are drilled close to the intended outline of the tunnel. The trimmers have the longest delays, particularly at the top of the tunnel. 

These pixels are found on concentric rings about the center of the pattern. 

For isotropic materials all reflections represent concentric rings (Debye-Scherrer rings) in an image recorded on 2D detector5 if during exposure the detector was... 

Concentric-Ring Sparger Consider for example, a configuration of four concentric rings of 0.4-m diameter supplied by a number of gas entry points. 

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