Tenth-value thickness

Moteff, J. Tenth-value Thicknesses for Gamma-ray Absorption, Nucleonics, 13(7) 24 (1956). 

Because attenuation is exponential, the effect of different shields can be evaluated by use of "half-value thickness" or "tenth-value thickness."... 

Along the same line, the tenth-value layer (TVL) is defined by the thickness of the absorber that reduces the initial intensity of the photons by a factor of 10. It is given by... 

The information discussed above is summarized in Table I. This includes the X-ray mean energy, the X-ray emission efficiency, the tenth value layer for attenuation in water, the optimum thickness of water for maximum X-ray power utilization efficiency and the DUR at... 

Electron Energy (MeV) X-ray Mean Energy (MeV) X-ray Emission Effic. (%) Tenth Value Layer (cm) Present Work Previous Calc. Meas. Work Optimum Thickness Double Sided (g/cm2) DUR ... 

Estimates of the relative concentations of selected elements in fine particles collected upstream from the FGD system are listed in Table II. The values listed are some of the highest concentrations yet reported in the literature for fine coal- derived aerosols, especially those of V, Cr, and 2n, which lie in the tenth-percent range. Additional enhancements in the concentration of these elements resulting from FGD were about a factor of 2 for V, U, W, and As, a factor of 4 for Cr and Mn, and a factor of 15 for Se. If, as predicted by vapor-deposition models, the mass of there constituents resides in 0.02-ym-thick surface layers (10), then the surface concentration would be yet another 5 times greater, yielding concentrations of V, Zn, Cr, and Se in the range of 1 to 5%. 

Since both laminar and turbulent boundary layers contain laminar or viscous layers, it would seem logical that diffusion would primarily take place across these regions. If the boundary layer thickness were known, assuming a linear decrease in concentration, Eq. 10.3 could be used to estimate diffusion current. Unfortunately, the point of uniform velocity is not necessarily the point of uniform concentration. This is because particles, with their large inertia compared to air, can be carried into laminar boundary regions by mixing as well as by diffusion. The value for 8 in Eq. 10.3 will always be less than the equivalent value for the aerodynamic boundary layer thickness, in some cases being only one-tenth or even smaller (Levich, 1962). 

Typical values for crazes in glassy polymers [29,30,38] are a few microns in thickness and tenths of millimeters in length. The measures of Acr and Ac are used by Brown and Ward [38] to estimate the toughness and the craze... 

In his studies Sheludko established that lower values (hundredths of mN/m) of excessive pressure (see Chapter VII, 1), Acf, were typical for the common black films, as compared to the Newtonian black films (tenths of mN/m) [27,31,32], The thickness of common film exceeds 7 nm (Fig. VIII-7). One can observe reversible transitions between these two types of films upon changes in the capillary pressure. The relationship between the... 

To understand how chemical reaction enhances the mass transfer process, consider the concentration gradients sketched in Figure 7.4. For /M = 3, the gradient at the interface is about three times steeper than that for physical absorption, which is shown as a dashed line. Much of the A reacts quite close to the interface, and a negligible amount diffuses into the bulk liquid. For -/M = 10, the rate of absorption of A is enhanced 10-fold, as if the effective film thickness was only one-tenth the actual value. 

In the literature, most studies have adopted the approximate guideline of limiting the indentation depth to less than one tenth of the film thickness in order to obtain reliable values for the elastic modulus of the film . In the present study we have shown that, for the materials investigated here, indentation depths up to 20% of film thickness could be used before the influence of the substrate became much prominent. 

Spin-casting is the most common method of preparation of thin films of desired 1-3 (im thickness. Material solubility in traditional spin-casting solvents, solution viscosity, and spinning speed are important variables that define material homogeneity and thus scattering loss. For multicomponent composite materials, care must be exercised to avoid phase separation. Typical scattering loss values should be a few tenths of a dB/cm but losses of many dB/cm can be observed if the aforementioned conditions are not controlled. 

Figure 1 shows the simulated concentration profile of hydroxyl radicals (Eq. 14 and 15) during oxygen evolution as a function of the distance from the electrode surface. It can be seen that, for a ciurent density of j = 300 A m, the thickness of the reaction layer is about 1 pm, whereas the maximum (siuface) concentration of hydroxyl radicals reaches values in the range of several tenths of pM. 

Calculations for other oxides for which the standard free-energy difference between amorphous and crystalline oxides is large yield correspondingly smaller critical thicknesses [9]. For example, for MgO on Mg the value is on the order of a few tenths of a nanometer, i.e. less than a lattice parameter, such that vitreous MgO would not be expected to form. 

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