Surface tension isotherms of a free surface and grain boundaries in the Cu-Sn system

Surface tension of pure copper and its alloys with Sn has been measured at 1000°C in a hydrogen atmosphere. Surface tension of a free surface equaled 1.81 N/m for pure copper, and 1.55, 1.38, and 1.28 N/m for the alloys with 0.05, 0.22, and 0.33 at % Sn, respectively; surface tension at grain boundaries equaled 0.5 N/m for pure copper, and 0.36, 0.3, and 0.23 N/m for the alloys, respectively. Based on these data, the concentration dependence of tin absorption at a free surface and grain boundaries has been calculated. Parameters of Sn absorption at grain boundaries and a free surface of copper have been compared with those of Sb and Bi.     

The Effect of Nucleators on the Quality of the Surface of Glass-Ceramic Denture Coatings

The effect of nucleator additives on the surface relief and the degree of crystallization of material intended for the dentine and enamel layers of artificial denture is considered. It is established that hydroxyapatite additive is optimal for producing the required relief in the prime and dentine layers.     

Analysis of supersaturation and nucleation in a moving solution droplet with flowing supercritical carbon dioxide

A supercritical antisolvent (SAS) process is employed for production of solid nanoparticles from atomized droplets of dilute solution in a flowing supercritical carbon dioxide (SC CO₂) stream by attaining extremely high, very rapid, and uniform supersaturation. This is facilitated by a two‐way mass transfer of CO₂ and solvent, to and from the droplet respectively, rendering rapid reduction in equilibrium solubility of the solid solute in the ternary solution. The present work analyses the degree of supersaturation and nucleation kinetics in a single droplet of cholesterol solution in acetone during its flight in a flowing SC CO₂ stream. Both temperature and composition are assumed to be uniform within the droplet, and their variations with time are calculated by balancing the heat and mass transfer fluxes to and from the droplet. The equilibrium solubility of cholesterol with CO₂ dissolution has been predicted as being directly proportional to the Partial Molar Volume Fraction (PMVF) of acetone in the binary (CO₂–acetone) system. The degree of supersaturation has been simulated up to the time required to attain almost zero cholesterol solubility in the droplet for evaluating the rate of nucleation and the size of the stable critical nuclei formed. The effects of process parameters have been analysed in the pressure range of 7.1–35.0 MPa, temperature range of 313–333 K, SC CO₂ flow rate of 0.1136–1.136 mol s^?1, the ratio of the volumetric flow rates of CO₂‐to‐solution in the range of 100–1000, and the initial mole fraction of cholesterol in acetone solution in the range of 0.0025–0.010. The results confirm an extremely high and rapid increase in degree of supersaturation, very high nucleation rates and stable critical nucleus diameter of the order of a nanometre. Copyright © 2005 Society of Chemical Industry     

Estimation of fouling in a plate heat exchanger through the application of neural networks

Pasteurization is an important, if not the most important, process step in the packaging of milk. It is subject to alterations stemming from the variation in the temperature, pH and raw milk quality. The variability may manifest itself in changes in the formation of the deposit (fouling) in the pasteurization unit, such that there is a need for tools, both instrumentation and computational, to help in monitoring the process and keeping it on the desired course. In this paper we describe a practical procedure based on artificial neural networks (ANN) that allows prediction of the deposit thickness, the overall heat transfer coefficient and the critical time (the time that the unit has to be stopped for cleaning) for reducing the impact of fouling on such processes. The procedure determines when the cleaning operation is required once the system is under critical conditions of operations. A combination of fundamental studies and plant measurements were used for study of the operating conditions and thus evaluation of the trades‐offs between operating conditions and longer operating life span. The results are encouraging, enough to validate current operating industrial techniques. Copyright © 2005 Society of Chemical Industry     

Intraoperative neurological monitoring

Intraoperative neurological monitoring (INM) is the evaluation of the nervous system within the operating room (OR) environment. In this paper, the INM system is tested in a clinical setting in comparison with conventional somatosensory evoked potential (SEP) monitoring. The study results demonstrate the capability of the INM system in extracting clearer and more stable SEP signals. The high SNR of SEP signals collected in various clinical environments, including the OR, makes the INM system a robust platform for continuous monitoring. While the current use of EP monitoring is limited to intermittent analysis by a highly trained clinical neurophysiologist, the authors believe in changing this paradigm by developing continuous monitoring systems, such as the INM system, capable of automated quantitative EP analysis. This noninvasive monitoring modality will allow for a wider range of use in clinical practice. Based on volunteer and clinical patient studies, the INM monitoring system demonstrates much greater reliability and accuracy via the artifact rejection and denoising strategies. It provides more strategic filtering options for different situations under which the clinical SEP response signal could be greatly contaminated and distorted. Furthermore, the INM system offers a promising approach to signal extraction in real-time monitoring during SEP research.     

The Grey-Rankin bound for nonbinary codes

The Grey-Rankin bound for nonbinary codes is obtained. Examples of codes meeting this bound are given. Original Russian Text Ş L.A. Bassalygo, S.M. Dodunekov, V.A. Zinoviev, T. Helleseth, 2006, published in Problemy Peredachi Informatsii, 2006, Vol. 42, No. 3, pp. 37–44. Supported in part by the Russian Foundation for Basic Research, project no. 06-01-00226.     

Safety assessment of liquid radioactive wastes buried for a long time in deep repositories

The concepts of specific and absolute toxicity permit distinguishing in radioactive wastes belonging to different categories the particular components that present the greatest ecological danger at different stages of their disposal in repositories. It is shown that transuranium elements determine the toxicity parameter of high-and medium-level wastes only 350–400 years after initial disposal. At the present stage of operation of deep repositories, the behavior of the long-lived fission products of ⁹⁰Sr and ¹³⁷Cs is most important. For low-level wastes, the chemical and not the radioactive component is most dangerous. __________ Translated from Atomnaya énergiya,Vol. 100, No. 2, pp. 86–92, February, 2006.     

Distribution of investments in the stock market, information types, and algorithmic complexity

For a simplest mathematical model of a stock market, the problem of optimal distribution of investments among different securities (stocks, bonds, etc.) is considered. Our results, which are obtained in terms of algorithmic complexity, allow to discuss heuristically the properties of sufficiently complex security portfolios in the conditions of daily changing return rates. All considerations are given in the combinatorial framework and do not use any probabilistic models.     

Principles of reference-aided decision making

A unified approach to decision making with extremal many-criteria models, expert estimates, and voting is developed on the basis of reference and distance concepts and taxonomy methods. It involves the solution of many-criteria problems with the Pareto optimum. Examples demonstrating the effectiveness and universality of the approach are given.