Variable Thickness

Materials to be inspected are, for example Concrete with lest frequencies of about 50 kHz, sandwich components with 500 kHz, metallic materials up to 10 MHz and thin components up to 35 MHz. Apart from the difference of materials, variable thicknesses and attenuations require different amplifications and signal processings. 

Thickness. The traditional definition of thermal conductivity as an intrinsic property of a material where conduction is the only mode of heat transmission is not appHcable to low density materials. Although radiation between parallel surfaces is independent of distance, the measurement of X where radiation is significant requires the introduction of an additional variable, thickness. The thickness effect is observed in materials of low density at ambient temperatures and in materials of higher density at elevated temperatures. It depends on the radiation permeance of the materials, which in turn is influenced by the absorption coefficient and the density. For a cellular plastic material having a density on the order of 10 kg/m, the difference between a 25 and 100 mm thick specimen ranges from 12—15%. This reduces to less than 4% for a density of 48 kg/m. References 23—27 discuss the issue of thickness in more detail. 

The spht is of variable thickness, and some of the spUt is too thin for leather production. The thin parts are trimmed off and discarded for coUagen recovery. The trimmed spUt is tanned separately. 

For the composite spoiler design, the bottom is a variable-thickness skin on one side in Figure 1-33, but with composite materials that construction is not difficult. We do not have to chem-mill a composite material to change its thickness. All we do is stop building up the material in layers in the middle, but continue to build it up at the sides. That s a very natural process for composite materials and does not involve a costly machining operation. Instead of machined extruded stiffeners, a honeycomb core is placed on the inside of the laminae. That honeycomb... 

Disharmonic folds—(o As in layered rock that have variable thickness and competence and, thereby, fold in accordance to their ability (see Figure 2-46). 

Richard, A. and Nicolaides, G., Differential Aeration Corrosion of Passivating Metal Under a Moist Film of Locally Variable Thickness , J. Electrochem. Soc., 121, 183 (1974)... 

Consequently, the composite may be considered as consisting of three phases, that is the matrix, the inclusions and a third phase, which is a layer of variable thickness, including all these changes and which surrounds each one of the inclusions. This hybrid phase is called the mesophase. 

Underdosing and overdosing of the slick because of its variable thickness... 

MMT (32) is a 1- or 2-dimensional solute transport numerical groundwater model, to be driven off-line by a flow transport, such as VTT (Variable Thickness Transport). MMT employs the random-walk numerical method and was originally developed for radionuclide transport. The model accounts for advection, sorption and decay. 

Successful development of such systems will lead to foamed materials having useful stress-absorbing characteristics in addition to controlled physics properties. Although our work in this area is currently in a very early stage, prototype materials have been successfully synthesized and assessed structurally using three-dimensional (3D) X-ray microtomography. The technique offers a unique insight into the internal microstructure of cellular materials (see Fig. 3). The diameter of the mainly open cell pores varies from approximately 100 to 250 pm (the resolution of the instrument is 5 pm), with cell walls of variable thickness. 

Figure 5.3 Diagram depicts the further-designed studies to test our hypothesis with respect to standardization of immunohistochemistry based on the antigen retrieval technique exemplified in a multiple direction to draw a conclusion, (a) Periods of formalin fixation, (b) Variable delay of fixation, (c) Storage of FFPE tissue blocks or sections, (d) Variable thickness of FFPE tissue sections, (e) Other variable conditions of processing FFPE tissue blocks. The stereoscopic frame of a cube represents the reliable limitation of quantitative IFIC demonstrated by serial studies as recommended in the text. Reproduced with permission from Shi et al., J. Histochem. Cytochem. 2007 55 105-109.

Powder impression moulding (PIM) can produce large parts such as truck beds (Dodge Dakota) with variable thickness skin and a foamed thermoplastic core, capable of structural performances. 

Because the mucus layer or the underlying cells may serve as either final accumulation sites of toxic gases or layers through which the gases diffuse en route to the blood, we need simplified models of these layers. Altshuler et al. have developed for these layers the only available model that can be used in a comprehensive system for calculating tissue doses of inhaled irritants. It assumes that the basement membrane of the tracheobronchial region is covered with three discrete layers an inner layer of variable thickness that contains the basal, goblet, and ciliated cells a 7-Mm middle layer composed of waterlike or serous fluid and a 7-Mm outer layer of viscous mucus. Recent work by E. S. Boatman and D. Luchtel (personal communication) in rabbits supports the concept of a continuous fluid layer however, airways smaller than 1 mm in diameter do not show separate mucus and serous-fluid layers. 

Chalcedony is a variety of quartz composed of fibrils that are not separable. The fibrils may have variable thickness, and lengths, from a few to hundreds of microns, and may be twisted (Fig. 2.19C). The fiber axis, usually perpendicular to the free or growing surface, is easily detected in the crystalline material consisting of tightly packed, parallel or subparallel fibrils. The range of color, and the mechanisms of inclusion of impurities, and especially of water and (OH) in chalcedony, have been described and discussed by many authors, most recently by Frondel (1978, 1982). 

The third aspect to consider is the electrochemical stability of the material used. For the oxygen reduction reaction, the electrode potential is highly anodic and at this potential, most metals dissolve actively in acid media or form passive oxide films that will Inhibit this reaction. The oxide forming metals can form non-conducting or semi-conducting oxide films of variable thickness. In alkaline solutions, the range of metals that can be used is broader and can include non-precious or semi-precious metals (Ni, Ag). 

All the structures belonging to this system have the sequence represented in the scheme of Figure 9. The rock-salt slab is made of four layers of type (AX), followed by slabs of variable thickness having the perovskite structure. Since the number of layers (AX) is even, every one of these structures is made of two identical halves shifted by t = l/2a + l/2b. The Tl-Ba system is isomorphous with the Bi-Sr system. However, compounds Bi2Sr2Can 1Cun02n+4 have superstructures whose atomic configurations have not been completely clarified. 

Again, decomposition of urea in an acidic metal salt solution in the presence of preformed particles can yield homogeneous layers of variable thicknesses of metal basic carbonates on the core materials of different chemical composition. In order to obtain uniformly coated particles (rather than a mixture of the latter and of the independently precipitated coating material), a balance between the amount of the initial dispersed matter and the concentration of the reacting solutes must be optimized. 

It appeared that the experimental conditions used in the present study favoured the formation of microspheres of a new type which could be defined as film-type microspheres. They consisted of spherical micromatrices comprising an internal void space and a polymeric membrane of variable thickness where the drug is dispersed in either a molecular or a solid state depending on the payload. 

Figure 8. Tangential section of coalified Persea wood cut thicker than that shown in Figure 7 to show effect of variable thickness on appearance. Note that the various coalified products are still readily differentiated. 113X...

Cells with solid electrodes have incorporated a thin-layer volume in the form of either a slab or cylindrical shell. The latter have all been of fixed L value, whereas the former have been constructed with either fixed or variable thickness. A comprehensive review of thin-layer cells and applications has been published [50]. Since many of these are quite complex and will only be of interest to the specialist, only one approach is described in detail here. 

Under the microscope (Fig. 76, Plate VII) they are mostly isolated, of marked dimensions and in the form of a ribbon of somewhat variable thickness. The wall is copiously and finely striated with pronounced, very deep fissures, which appear as dark lines, rather oblique to the axis of the fibre. In some cases thin fibres are detached from the walls in the form of very thin ribbons. The very wide lumen is clearly visible the ends are blunt and rounded, with very thick walls. The fibre consists of cellulose and is hence coloured blue with iodine and sulphuric acid. 

Figure 4.21. Geometrical scheme of a flow field pattern for a rotating liquid film with a variable thickness h(6). [Adapted, by permission, from J. A. Deiber, R.L. Cerro, Ind. Eng. Chem. Fund., 15 (1976), 103.]...

Figure 8.55 Ways of packing monoalcohols with variable thickness of substituent (a) thin substituents pack by translation or by 2, screw or glide operations, (b) with thicker substituents rings are favoured, (c) thicker substituents may also pack with more than one molecule in the asymmetric unit and (d) very thick substituents result in packing about higher order screw or improper rotation axes.84...

Crustal thickness in the Sicily volcanic province is about 20 to 25 km (Boccaletti et al. 1984 Him et al. 1997 Nicolich 2001, and references therein). The lithosphere shows variable thickness from about 50 km beneath the Ustica island, to 60 km beneath the Sicily Channel and some 70 km in the Etna and Iblei area (Calcagnile et al. 1982). Heath flow is about 50 to 70 mW/m2 at the regional scale but is higher than 80-100 mW/m2 in the areas affected by recent magmatism (Della Vedova et al. 2001). 

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