Work integrals for plutonium

Free energy changes in Pu disproportionation reactions can be measured by integrating the reaction isotherm with respect to one of the reaction products. Separate integrations can be made for the isotherms of the component reactions contributing to the equilibrium.Mound is operated for the U.S. Department of Energy by EG&G Mound Applied Technologies Incorporated under contract No. DE-AC04-88DP43495.     

Plutonium valence state distributions

A method for ascertaining equilibrium valence state distributions of plutonium in acid solutions as a function of the plutonium oxidation number and the solution acidity is illustrated with an example. The method may be more practical for manual use than methods based upon polynomial equations. Mound Laboratory is operated by Monsanto Research Corporation for the U.S. Atomic Energy Commission under Contract No. AT-33-1-GEN-53.     

Actinide pollutants and the oxygen/water couple

The redox potential of environmental water influences the speciation of pollutants like plutonium. This potential cannot be reliably predicted from diagrams for irreversible couples like oxygen/water.Mound is operated for the U. S. Department of Energy by EG&G Mound Applied Technologies Incorporated under Contract No. DE-AC04-88DP43495.     

Charge balance vs. charge conservation for plutonium

A recent paper about plutonium disproportionation confuses charge balance with charge conservation. To explain disproportionation, impossible solutions in which the charges do not balance were proposed.Mound is operated for the U. S. Department of Energy by EG & G Mound Applied Technologies Incorporated under Contract NO. DE-AC04-88DP43495.     

The ratio Pu(V)/Pu(IV) in natural water

The behavior of the ratio Pu(V)/Pu(IV) depends on whether the symbols represent absolute concentrations of soluble species, or fractions of the total soluble plutonium, or insoluble, colloidal substances.Mound is operated by EG&G Mound Applied Technologies for the U.S. Department of Energy under Contract No. DE-AC04-88DP43495.     

Environmental plutonium: Reference states and alpha coefficients

The results of plutonium oxidation state distribution calculations do not depend on special attention to any oxidation state as has been incorrectly supposed in some literature sources. Experimentally determined alpha coefficients for natural water could make the distribution of environmental plutonium easy to estimate with a programmable pocket calculator.Mound is operated for the U.S. Department of Energy by EG&G Mound Applied Technologies, Inc., under Contract No. DE-AC04-88DP43495.     

Formation of plutonium/IV/ colloid from plutonyl cations

Solutions of plutonyl cations in dilute acids gradually form Pu/IV/ polymer under the influence of alpha radiations. These systems have properties that can be illuminated by assuming conditions to be near equilibrium and constrained by mass conservation.Mound is operated by Monsanto Research Corporation for the U.S. Department of Energy under Contract DE-AC04-76-DP00053.     

Continuous removal of radioactive cobalt from water

More than 99% of radioactive cobalt can be removed from water by precipitation as cobalt/III/ hydroxide. The process is continuous and uses either sodium hypochlorite or oxygen and calcium sulfite to oxidize the cobalt. Carbonate and phosphate interfere with cobalt removal, but the process has potential for other applications such as thallium removal and sewage treatment.Mound is operated by Monsanto Research Corporation for the U.S. Department of Energy under Contract No. DE-AC04-76-DP00053.     

Environmental plutonium: What is the redox potential of seawater?

The potential of seawater has recently been reported as 0.8 V. This number conflicts with many literature sources on oceanography.Mount is operated for the U.S. Department of Energy by EG&G Mound Applied Technologies Incorporated under contract No. DE-AC04-88DP43495.     

Potentiometric titration of plutonium

In the potentiometric titration of plutonium(III), it has been customary to take the equivalence point as the inflection point on a plot of potential vs. volume of titrant.¹ That the stoichiometric end point corresponds to the inflection point does not seem to have been theoretically demonstrated, however. The purpose of this letter is to suggest that these points may not correspond in the potentiometric titration of plutonium(III). Mound Laboratory is operated by Monsanto Research Corporation for USERDA under contract No. EY-76-C-04-0053.     

Activation of uranium metal

Treatment of uranium with hydrochloric or hydrobromic acid produces an adherent layer of hydride on the metal surface. When this hydride is decomposed by heat in a vacuum, the resulting metal surface reacts immediately with hydrogen at ambient temperature.Mound is operated by Monsanto Researh Corporation for the U.S. Department of Energy under Contract No. DE-AC04-76-DP00053.     

Programming the HP 48 Calculator to Control the Lab Works Interface

While the balanced chemical equations for a multireaction system are generally not unique, the minimum number of independent equations, R, is a characteristic property of the system. Deleting one nonspectator species from the system leads to a system with R reduced by one. In this way each system can be reduced to a single-reaction system and ultimately to a no-reaction system. The least number of chemical species that can be deleted to obtain a no-reaction system equals R. Every multireaction system, therefore, can be reduced to a number of single-reaction equations which can be balanced by any one of the standard techniques. Some examples are given where balancing by inspection is employed.     

Chemical Equations for Multireaction Systems

While the balanced chemical equations for a multireaction system are generally not unique, the minimum number of independent equations, R, is a characteristic property of the system. Deleting one nonspectator species from the system leads to a system with R reduced by one. In this way each system can be reduced to a single-reaction system and ultimately to a no-reaction system. The least number of chemical species that can be deleted to obtain a no-reaction system equals R. Every multireaction system, therefore, can be reduced to a number of single-reaction equations which can be balanced by any one of the standard techniques. Some examples are given where balancing by inspection is employed.     

On finding the rate constants of linear and nonlinear systems

In lowest approximation, a certain chemical reaction is described by a system of first-order linear differential equations with unknown constant coefficients. One can therefore write down an expression for the state of the system at time t, and from this find the endpoint of the reaction in terms of the initial state and the rate constants. The relative values of some rate constants can then be estimated from experimental data. A better approximation in which the differential equations are nonlinear is also considered, and it turns out that because of symmetry in the reaction, the relationship between the final state and the ratios of the rate constants is unchanged. Although the differential equations now appear much less tractable, the problem of relating the rate constants to the endpoint of the reaction can be formulated and solved in terms of probabilities. The results illustrate an important property of reaction schemes in which some of the steps are reversible. More generally, this is a property of differential equations: provided that they continue to satisfy certain linear constraints, the parameters of a linear system of ordinary differential equations can vary without affecting the asymptotic solution.     

Existence, uniqueness, and calculation of the physically acceptable solution of a particular case of the Sherman equations

When a chemical sample made of N elements is analyzed by using sequential selective excitation by monochromatic X-ray beams and selective measurement of the characteristic X-rays, the production of secondary fluorescence does not interfere with the measurements. This experimental situation leads to a particular simple case of the Sherman equations which can be written in this instance as linear equations. The linear equations thus obtained are shown to be very similar to the equations appearing in the classical models of Beattie and Brissey and of Lachance and Traill. The linear algebra proves the existence of N different sets of solutions, but the Perron Frobenius theorem ensures that there is one and only one physically feasible solution, and also leads to the method for obtaining it. This equation solution method can be extended to the equations appearing when standard samples of pure elements are also measured.The propagation of the errors in the measurements to the errors in the sample concentrations has been calculated and simulated, and the results have shown that the solution is well conditioned.     

A graphical tool for the prediction of vicinal proton-proton 3J(HH) coupling constants

The easy to use and free available graphical tool MestRe-J, developed for Win-32 platforms, calculates the vicinal proton-proton coupling constants 3J(HH) from the torsion angle phi between the coupled protons for the two kinds of generalized Karplus equations developed by Altona's group as well as for equations from other authors. Besides the classical Haasnoot-de Leeuw-Altona equations, including individual substituent effects that depend on their relative Huggins's electronegativities Deltachi, the program incorporates the more recent and precise Díez-Altona-Donders equations. The substituent effects in these equations, that include effects of interactions between substituents, depend on substituent parameters lambda optimized from the 3J(HH) couplings to methyl groups. Weighted time-averaged couplings can be calculated. The equations for 3J(HH) can be solved to provide the torsion angles phi.     

A complete decoupling of Faddeev-like equations for three arrangement systems; applications to HH2 collision

A complete decoupling of time-dependent Faddeev-like equations for three identical particles is presented in terms of an operator formalism. No restriction to pairwise additive interaction needs to be made. Our decoupled equations can be looked at as being a generalization of the special decoupled versions of Faddeev and Lovelace in so far as they include all irreducible representations of the permutation group S₃. Thus, the new equations also apply to three composite particles of any spin. An application is made for the system composed of three H-atoms. In particular we show how the cross sections of ortho—para transitions are directly related to the transition operators obtained from the decoupled equations.     

Sequences of ultrafast non-resonant multiphoton transitions in a three-electronic level molecule

Non-resonant multiphoton transitions between three electronic states of a molecular system are studied. Based on a projection operator formalism which is formulated in the framework of the so-called time-local as well as the time-nonlocal approach, time-dependent Schrödinger equations are obtained, which include effective couplings to the laser field. For both procedures a slowly varying amplitude approximation can be invoked. The resulting time-local equations are solved in a much more efficient way than the original effective Schrödinger equations. The validity of these approximations is verified numerically for a two-photon process. Furthermore, the effective Schrödinger equations are specified to sequences of two-photon and three-photon transitions. The derived equations are applied to a molecular system consisting of three electronic states with Morse-type potential energy curves. Using different laser pulse scenarios the conditions are discussed under which a sequence of two-photon and three-photon transitions can take place.     

多组分体系单级萃取平衡的Newton-Raphson算法

提出了一种多组分体系串级萃取动态仿真中的单级萃取平衡和物料计算的新同了有机相萃取量,水相洗涤量和混合萃取比等限制条件下两相组成关系的２λ元非线性方程组,构造以水相中某一组分的平衡含量为变量的目标函数,采用Ｎｅｗｔｏｎ－Ｒａｐｈｓｏｎ迭代求解,并以萃取平衡和物料平衡得到该级其它所有组分在两相的含量。     

A differential approach to calculating osmotic equilibrium for multisolvent systems

A differential approach to the calculation of osmotic pressure of multisolvent systems within the Lewis–Randall framework is presented in this paper. Exact differential equations relating the osmotic pressure and the system composition along paths of constant solvent chemical potential are obtained and numerically solved. Although even for the simple case of an ideal solution no analytic expression for the osmotic pressure can be obtained, the system of differential equations does not pose numerical difficulties to be solved. Examples of the use of the proposed methodology are presented using the two-suffix Margules and Flory–Huggins equations, allowing an assessment of the influence of liquid-phase non-ideality on the performance of the method, and showing that it can be applied even for systems wherein liquid–liquid phase equilibrium occurs.