Saturation stage

In the paper [112] the following accumulation equation was proposed on the basis of results of simulating the accumulation of point defects in a one-dimensional crystal in the saturation stage ... 

The two stage process has the advantage to combine the moderate pressure in deep HDS stage with the same moderate pressure in aromatics saturation stage since the second stage can be operated essentially at low sulphur content. It should be mentioned that the moderate to severe proposed reduction of aromatics content in diesel fuels will have a major impact on the hydrogen availability on the refinery. 

A number of investigations have focused on potential plant and soil responses as indicators of N saturation stages. Analyses of results from multiple studies have shown that forest floor chemistry can vary with N inputs. For example, forest floor C N ratios have been reported to decrease with N deposition in the northeastern United States (Aber et al. 2003) and Europe (Emmett et al. 1998 Gundersen et al. 1998). As discussed above, decreased forest floor C N (or increased percent N) could result from increased decomposition of soil organic matter, higher concentrations of N in litter and root inputs to soils, greater incorporation of N inputs into microbial biomass, or any combination of these responses to N deposition. Forest floor C N ratios typically vary with climate and tree species composition in the absence of elevated N deposition. For example, forest floors developing... 

As a product moves into the maturity and saturation stages, it is necessary to review past pricing decisions and determine the desirability of a price change. Replacement sales now constitute the major demand, and manufacturers may also incur regional competition from local brands. Market conditions do not appear to warrant a price increase, hence the pricing decision usually is to reduce price or stand pat. 

All the samples had a polycrystalline structure. Nevertheless, it has been established that the appearance of the isolated clusters of defects is observed in the FSZ structure at the initial stage of irradiation with high-energy xenon and iodine ions. In the sequel, the density of defects increases. However, at a relatively low dose of 3 dpa, the saturation stage is formed, and after its formation the material structure remains unchanged. The exposure of monoclinic zirconium oxide to the radiation dose of 2 dpa results in the transformation of monocUnic structme into more densely packed cubic and tetragonal structmes. During further increase in the radiation dose up to 680 dpa, amorphization is not observed. 

Stage I. Saturation stage A polymer is introduced into a pressure vessel under a controlled... 

Furthermore, the plasticization effect by CO2 of amorphous polymers decreases the effective value of the glass transition temperature (Tg ef) [68-70]. The relationship between this Tg ef and the temperature of the saturation stage allows differentiating two main gas processes. 

On the other hand, at saturation temperatures lower than the Tg f of the polymer (ie, the polymer is in the glassy state at the end of the saturation stage), the foaming process will be triggered in a second stage by heating the sample over its Tg ef (Fig. 9.5). This process is usually called two-step or solid-state foaming [19]. 

Figure 9.5 Schemes of (a) one-step gas dissolution foaming and (b) two-step gas dissolution foaming. Evolution of the samples from solid to foamed are represented schematically, together with the usual evolution of both temperature (T) and pressure (P) during the foaming process (from the saturation stage to the foaming stage).

Extruded films of PP/rubber blends [89] showed that the CO2 concentration is higher in the rubber domains than in the PP matrix. In addition, as expected, the rubber domains were the only place where the porous phase can develop according to different CO2 solubility and viscoelastic behavior of both phases. Nanostructured PP/TPS blends were foamed with a saturation stage performed at 20 MPa and 25°C during 1 h, followed by a pressure release at a rate of 1 MPa/s and a foaming stage at 120°C. In this study the 80-PP/20-HSIS blend presented the best results, with pore sizes of approximately 200-400nm but low porosities below 25% (Fig. 9.19). Another remarkable output from this study is the perfect relationship found between the sizes of the rubber domains of the precursor and the pores of the foam as well as between the shape and orientation of the nanostructure of the precursor and the porous structure of the foam. 

PS-b-PFMA films were foamed by a modified gas foaming process to obtain nanoporous polymers [83,84,88,91]. After the usual saturation stage (1 h at pressures between 7.5 and 30MPa and 60°C), the temperature was quenched to 0°C, maintaining the CO2 pressure, and then the pressure was released at a very low rate of 0.5 MPa/ min. The resulting porous structures were studied in thick films by SAXS and SEM, obtaining pore sizes between 10 and 30 nm and very high pore densities more than 10 pores/cm, but low porosity ( 30% Fig. 9.20). Moreover, they found that without... 

Films of PMMA/copolymer blends nsed by Siripurapu et al. [77] were foamed by a saturation stage nnder pressnres from 6.89 to 34.5 MPa and temperatures between 40 and 120°C, followed by a qnick depressurization stage under isothermal conditions to promote the pressure-indnced phase separation. They observed that the copolymers play a role in the stabilization of the growing pores, but only a clear effect on the pore nucleation was found for PMMA blends with 2wt% of a low-molecular-weight PMMA-b-PFMA BCP foamed at 40°C and 34.5 MPa, leading to pore sizes of approximately 300 nm and pore densities of approximately 10 pores/cm. No information about the porosities obtained is provided, but according to the published parameters of the porous structure with low porosities can be expected. 

Pleochroic haloes have been used to date minerals and rocks. The method depends on the fact that the intensity of their colors increases with the alpha dose to which they have been exposed. The relationship between the two may fall into any one of three categories. In the first place, a normal stage exists in which color increases linearly with radiation dose. Secondly, there is a saturated stage in which the color reaches a maximum density and does not show any further increase with increasing radiation dose. Thirdly, there is an inversion stage in which coloration actually decreases with the intensity of the radiation dose - this is caused by extreme radiation damage. Only those from the first category are used for age determinations. 

Figure 17.L10 shows an area fraction of the second phase arranged in the array (f) as a function of trial number of arranging the second phase with various aspect ratios. In this simulation, / increase rapidly with trial number in the early stage, but it saturates to a certain value, which is lower in case of higher aspect ratio. Graphic expressions of the computer simulation with the second phase of different aspect ratios in a nearly saturated stage are shown in Figure 17.1.11. It is clearly seen that the second phases with higher aspect ratio...

Fig. 5.8 Distribution of fluid concentration at the fully-saturated stage of absorption and initial condition for desorption (Weitsman and Guo 2002)...

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