Analysis of instantaneous cardiac rhythm in a model of multifractal dynamics based on Holter monitoring

For the specific analysis of the variability of RR intervals of the cardiac rhythm, a method for measuring the instantaneous cardiac rhythm (ICR) represented by a multifractal dynamical model (MDM) has been developed. The advantages of this method, compared to the statistical methods of analysis of the RR intervals used, have been demonstrated. The method allows possible catastrophes of the cardiovascular system to be predicted. Using the data of Holter monitoring and the program system developed, we have plotted ICR curves, an ICR piecewise linear trend, and variability charts for three randomly chosen time intervals. The self-similarity (fractality) of the ICR up to an accuracy of 5% has been shown based on the explicit data. The MDM parameters have been calculated based on the ICR data. The analysis of the dynamics of these parameters has been conducted and their compliance with the status of the patient examined has been studied. The relevance of the ICR examination within MDM is closely related to the necessity of recognizing new markers of adverse cardiovascular episodes. The research performed shows that the results obtained could be taken as a basis for developing a new mathematical method of ICR examination based on Holter monitoring.     

Beyond-design-basis regimes of uranium stripping and of carbonate regeneration of the solvent

Beyond-design-basis regimes of centrifugal contactors for U stripping and of mixer–settlers for carbonate regeneration of the solvent, 30% TBP in Isopar M, were studied from the viewpoint of the influence of incomplete uranium stripping on the phase stability of the extraction system in the step of the carbonate scrubbing of the solvent. Dynamic relationship between these two operations was determined. A mathematical model of uranium stripping at stepwise–20% deviation from the nominal value was developed and verified; it was shown that the beyond-design-basis regime develops in such apparatuses within 4 h at the total trial time longer than 8 h. The mathematical relationships obtained were used in the development of software for calculating transient processes that occur when the stream parameters in the course of carbonate regeneration of the solvent change. The beyond-design-basis regime of the solvent regeneration was found to have two regions: region of stoichiometric excess of carbonate ions over uranyl ions with the risk of precipitation and region of excess of uranyl ions over carbonate ions with acidification of the unit and uranium breakthrough with the recycled solvent. The conditions of the tests performed correspond to the second region.     

Interaction of thorium and plutonium with pertechnetic acid in the course of extraction from nitric acid solutions with tributyl phosphate in diluent and its mathematical description

Databases on the coextraction of Th or Pu with Tc into 30% TBP in hydrocarbon diluent at 25°С are presented. The coextraction leads to mutual enhancement of the extraction of all the elements. The interactions in the system are described within the framework of a new approach to modeling, using the previously suggested and additional equations of concurrently occurring chemical reactions. The apparent equilibrium constants of these reactions are calculated.     

Controllable Generation of a Submillimeter Single Bubble in Molten Metal Using a Low-Pressure Macrosized Cavity

Metallurgical and Materials Transactions B - We develop a method for generation of a single gas bubble in a pool of molten metal. The method can be useful for applications and research studies...     

Ways of technetium and neptunium localization in extraction reprocessing of spent nuclear fuel from nuclear power plants

Possible ways of Tc and Np localization within the framework of the first extraction cycle of the Purex process are considered. Experimental data are presented on Tc localization in the high-level raffinate as applied to the RT-1 flowsheet, in the zirconium-tritium strip, and in the Pu-Np product or in the scrub from the unit of the barrier reductive scrubbing of the uranium solvent product as applied to six-unit extraction scheme in the design of the Experimental and Demonstration Center. For the latter case, the possibility of Np localization before and after Pu stripping was also examined.     

Equilibrium distributions of shallow-level impurity and potential in the near-surface region of a semiconductor in a model with a completely depleted layer

A model of completely depleted layer was used to derive analytical expressions for equilibrium distributions of shallow-level impurity, electric field, and potential in the near-surface region of a semiconductor. The results of calculation were used to estimate the variation in the parameters of a finite-size structure. It was found that, in the approximation used, it was possible to reduce the concentration of electrically active defects by several times for semiconductor layers ∼1 μm thick. __________ Translated from Fizika i Tekhnika Poluprovodnikov, Vol. 34, No. 4, 2000, pp. 455–458. Original Russian Text Copyright ? 2000 by Gavrilovets, Bondarenko, Kudinov, Korablev.