Repartitioning

If uranium is internally cycled in coastal environments or if the riverine delivery of U shows some variability, residence time estimates (regardless of their precision) cannot be sensitive indicators of oceanic uranium reactivity. Based on very precise measurements of dissolved uranium in the open ocean, Chen et alJ concluded that uranium may be somewhat more reactive in marine environments than previously inferred. Furthermore, recent studies in high-energy coastal environments " indicate that uranium may be actively cycled and repartitioned (non-conservative) from one phase to the next. 

In the asymptotic region, an electron approximately experiences a Z /f potential, where Z is the charge of the molecule-minus-one-electron ( Z = 1 in the case of a neutral molecule) and r the distance between the electron and the center of the charge repartition of the molecule-minus -one-electron. Thus the ip orbital describing the state of that electron must be close to the asymptotic form of the irregular solution of the Schrodinger equation for the hydrogen-like atom with atomic number Z. ... 

J.E. Dalidowicz, T.D. Thomson, and G.E. Babbitt, Ractopamine hydrochloride, a phenethanolamine repartitioning agent, in Xenobiotics in Food Producing Animals Metabolism and Residues, ed. D.H. Hutson, D.R. Hawkins, G.D. Paulson, and C.B. Stru-ble, American Chemical Society, Washington, DC, Chapter 16, pp. 234-243 (1992). 

At 375°C with the ZSM-5, the main products formed are n-alkanes. Other products are observed ramified alkanes and alkenes, 1-alkenes, aromatics and cyclic saturated hydrocarbons. The majority of hydrocarbons formed have a carbon number between 3 to 6. In the case of the zeolite Y, the n-alkanes and similar secondary products are formed but their repartition is different i.e. the normal and ramified alkanes are the main products and no cyclic compound can be observed. All these products are in higher quantity with the ZSM-5 than with the zeolite Y. This is in agreement with the calculated n-dodecane conversions. With the increase of the temperature, the same products are formed but their quantities increase. The analysis of the gaseous phase shows the presence of hydrogen, light normal and ramified alkanes and 1-alkenes. 

Ribeyre, F. and A. Boudou. 1984. Bioaccumulation et repartition tissulaire du mercure-HgCl2 et CH3HgCl2 -chez Salmo gairdneri apres contamination par voie directe. Water Air Soil Pollut. 23 169-186. 

We say the solution is saturated if solute is partitioned between a liquid-phase solution and undissolved, solid material (Figure 5.16). In other words, the solution contains as much solute as is feasible, thermodynamically, while the remainder remains as solid. The best way to tell whether a solution is saturated, therefore, is to look for undissolved solid. If -Repartition) is small then we say that not much of the solute resides in solution, so most of the salt remains as solid - we say the salt is not very soluble. Conversely, most, if not all, of the salt enters solution if K(partition) is large. 

Like all equilibrium constants, the value of Repartition) depends on temperature, sometimes strongly so. It also depends on the solvent polarity. For example, K(partition)... 

The energy necessary to dissolve 1 mol of solute is called the enthalpy of solution Absolution) (cf- P- 125). A value of AH can be estimated by analysing the solubility s of a solute (which is clearly a function of Repartition)) w t 1 temperature T. 

Figure 7. Repartition of the main domains of biomaterials applications.

Casting microprobe analysis (Fig. 13.30) shows the very pronounced eggshell repartition of Pd and Sn across the diameter of the alumina beads. This is an important feature in the case of intragranular limited reactions such as selective hydrogenations. The thickness of the shell is very small (about 50 xm) and both elements are located in the same zone, which is a necessary condition for an interaction between the two metals. 

FIGURE 13.30. Repartitions of Pd and Sn obtained by casting p probe analysis for the PdOSn catalyst (PdO—Sn). 

E-ct-phenylcinnamic acid, 6 edges, 281 EDX, 168 EDX analyses, 315 EELS, 223 eggshell, 277 eggshell repartition, 257 electrical conductivity, 8 electro-optical properties and quantum confinement,... 

Audier, H.E. Ionisation et fragmentation en spectrometrie de masse I. sur la repartition de la charge positive entre fragment provenant des memes raptures. Org. Mass Spectrom. 1969,2,283-298. 

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