Penetration ratio

The biological processes in biofilms are either described by 1-order or 0-order kinetics. However, the 0-order reaction is of specific importance for sewer biofilms as is also the case for treatment processes of wastewater in biofilters. The saturation constant, Ks, is normally insignificant compared with the substrate concentration, and the biofilm kinetics [cf. Equation (2.20)], is therefore 0-order. As shown in Figure 2.8, two different conditions exist the biofilm is either fully penetrated or partly penetrated, corresponding to either a fully effective or a partly effective biofilm. The distinction between these two situations can be expressed by means of a dimensionless constant, P, called the penetration ratio (Harremoes, 1978). For each of these two situations, the flux of substrate across the biofilm surface can neglect the stagnant liquid film being calculated [Equations (2.23) and (2.25)] ... 

Tissue penetration of endotamponade media should be avoided because of non-calculable side effects. One way to reduce the penetration rate is the use of branched species. In a similar experiment as described above, small pieces of fatty tissue and muscle tissue from pig were immersed in the test liquids for 15 min and then rinsed with PFD to clean the surfaces. Table 13 shows the reduced ratio of penetration of branched perfluorobutyl-butane in comparison to the linear form (044 perfluorobutyl-n-butane and 044v 1-perfluorbutyl-2-methyl-propane, own unpublished results). The relative penetration ratio was determined on the basis of the concentration of the two types of perfluorobutyl-butane indicated by GC/MS measurements. 

Tissue penetration, particularly in the kidneys and prostate, is excellent (Table 2). Those quinolones with longer half-life have smaller penetration ratios... 

Fig. 5. Comparison of rat skin penetration ratio between ATP-vesicles and free Mg-ATP at 2, 4, and 24 h (F< 0.005, N= 9). Encapsulation of ATP dramatically increased nucleotide penetration through the skin. It appeared that the penetration occurred fast and the ATP was gradually metabolized or hydrolyzed with time...

Isoniazid, the mainstay in virtually any regimen to treat M. tuberculosis, penetrates the CSF with or without meningeal inflammation and achieves concentrations of more than 30 times the MIC of M. tuberculosis (MICs of 0.05 to 0.2 mg/L)." Rifampin s penetration of CSF approximates only 20% of sernm concentrations in the presence of meningeal inflammation. M. tuberculosis typically is so exquisitely sensitive to rifampin, however, that the low penetration ratio is of little clinical significance. However, the incidence of M. tuberculosis resistance to rifampin has increased, necessitating empirical multiple-antibiotic regimens. 

We can check that the available height of 2.3 mm is big enough to accommodate this diameter of wire. The penetration ratio X is (using the equivalent foil transformation)... 

Figure 14-14. Penetration ratio of the testprobe at 0.5g into the test samples against heat treatment temperature under various heating rates. Heating rates are (a) 20° C/min, (b) 10° C/min, (c) 1° C/min, and (d) 1° C/min with pre-heat treatment (Hasegawa, 2000).

Figure 14-20. Penetration ratios of (a) PhSiOs/z and (b) BnSiOs/2 nwnoliths under a probe load of 0.5 g and a heating rate of lO " C/min (Matsuda, 2000).

PEI. See poly(ethylenimine) penetration ratios of benzylsilsesquioxane, 326 polysilsesquixone thick films, 326 pentanedione (PD), 372 pentanedione-modified lithium-niobate precursors, 377 peptization mechanism acidic, 351 basic, 351 peptization of... 

Together these two ratios determine the degree of penetration of these reactor types into the total system nuclear capacity. The higher these ratios are the greater will be the breeder penetration, ratio (a) being more significant initially and ratio (b) on a long-term basis. 

None of the above methods is sufiBcient for neutrons, however. Neutrons penetrate mader so easily that the only effective approach is to use materials with a very high surface-to-vohuue ratio. This can be accomplished with small particles and exfoliated graphite, for instance, but the teclmique has essentially been abandoned in surface sdidies [7, 8]. 

Automotive and architectural laminates of PVB develop maximum impact strength near 20°C, as shown in Figure 2. This balance is obtained by the plasticizer-to-resin ratio and the molecular weight of the resins. It has been adjusted to this optimum temperature based on environmental conditions and automobile population at various ambient temperatures. The frequency and severity of vehicle occupant injuries vs temperature ranges at the accident location have been studied (5), and the results confirm the selection of the maximum performance temperature and decreasing penetration resistance at temperature extremes. 

Catalytic Properties. In zeoHtes, catalysis takes place preferentially within the intracrystaUine voids. Catalytic reactions are affected by aperture size and type of channel system, through which reactants and products must diffuse. Modification techniques include ion exchange, variation of Si/A1 ratio, hydrothermal dealumination or stabilization, which produces Lewis acidity, introduction of acidic groups such as bridging Si(OH)Al, which impart Briimsted acidity, and introducing dispersed metal phases such as noble metals. In addition, the zeoHte framework stmcture determines shape-selective effects. Several types have been demonstrated including reactant selectivity, product selectivity, and restricted transition-state selectivity (28). Nonshape-selective surface activity is observed on very small crystals, and it may be desirable to poison these sites selectively, eg, with bulky heterocycHc compounds unable to penetrate the channel apertures, or by surface sdation. 

The more penetrating P-rays were easily studied. In 1899 their direction of deflection in a magnetic field was observed, indicating the negative charge. Then Becquerel was able to deflect P-rays in electric and magnetic fields and thereby deterrnined the charge-to-mass ratio. This ratio showed that the mass was much smaller than that of any atom and corresponded to that of electrons. 

Mass-Transfer Coefficient Denoted by /c, K, and so on, the mass-transfer coefficient is the ratio of the flux to a concentration (or composition) difference. These coefficients generally represent rates of transfer that are much greater than those that occur by diffusion alone, as a result of convection or turbulence at the interface where mass transfer occurs. There exist several principles that relate that coefficient to the diffusivity and other fluid properties and to the intensity of motion and geometry. Examples that are outlined later are the film theoiy, the surface renewal theoiy, and the penetration the-oiy, all of which pertain to ideahzed cases. For many situations of practical interest like investigating the flow inside tubes and over flat surfaces as well as measuring external flowthrough banks of tubes, in fixed beds of particles, and the like, correlations have been developed that follow the same forms as the above theories. Examples of these are provided in the subsequent section on mass-transfer coefficient correlations. 

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