Plutonium disproportionation: maxima in the fractions of two oxidation states

The equilibrium fractions of soluble tri- and hexavalent Pu depend on the pH and the Pu oxidation number. Both fractions can exhibit maxima as the pH changes at constant N. A fraction at maximum can be used to estimate the equilibrium constant of the first hydrolysis reaction of tetravalent Pu. A new formula that renders least-squares estimates of this constant is illustrated.     

Alpha coefficients for tetravalent plutonium

The complexation of tetravalent plutonium in aqueous solutions derives from several sources including counterions, hydrolysis, additives, and impurities. A quantitative tool accounting for all such effects, known and unknown, is the alpha coefficient. It can be expressed in six ways by means of the equilibrium fractions of two Pu oxidation states.     

Detection of Water-in-Oil Droplet Formation within an Interfacial Region Formed by an Aqueous/1, 2-Dichloroethane Interface Using Transient Cell Impedance Measurements at a Single High Frequency

Russian Journal of Electrochemistry - The detection of water-in-oil (w/o) droplet formation within an interfacial region formed by an interface between an aqueous phase and 1,2-DCE using transient...     

A fast heuristic for minimising total average cycle stock subject to practical constraints

We address a problem of setting reorder intervals (time supplies) of a population of items, subject to a restricted set of possible intervals as well as a limit on the total number of replenishments per unit time, both important practical constraints. We provide a dynamic programming formulation for obtaining the optimal solution. In addition, a simple and efficient heuristic algorithm has been developed. Computational experiments show that the performance of the heuristic is excellent based on a set of realistic examples.     

The 3C/3D line ratio in Ni XIX: New Ab Initio theory and experimental results

We report a fully relativistic close-coupling calculation of the electron impact excitation of Ni xix to derive the 3C/3D line intensity ratio, with an uncertainty of 5%. Convergence of the calculation with respect to both channel coupling effects and the many interacting Rydberg series of resonances has been achieved. New measurements in an electron beam ion trap agree with our calculation. We show that the 3C/3D x-ray line ratio depends sensitively on both electron energy and beamwidth in an optically thin plasma. Accounting for this dependence improves the accuracy of the Ni abundance determination in astrophysical sources.     

A qualitative analysis of individual trajectories in the rotationally inelastic LiHHe collision system

Individual trajectories corresponding to classical mechanical collisions between He and LiH (rigid rotor) are examined to identify characteristics of the rotational transfer process. Torque is found to be useful for understanding rotational transitions and for defining an interaction time.     

Problems in plutonium chemistry: Generalized proportional equations and polymer formation

Summary This paper illustrates a generalized form of the method of proportional equations. It permits equilibrium calculations for Pu disproportionation reactions at any oxidation number and any pH by means of combining arbitrary proportions of tri- and hexavalent plutonium. Two methods for estimating the work of Pu polymer formation are illustrated. One method uses the work of disproportionation of tetravalent plutonium. The other method suggests the transition between hydrous Pu(IV) oxide and polymer is accompanied by a small change in free energy.