Numerical method for analyzing a stochastic stationary heat-conduction equation with random coefficients

A numerical method is suggested for defining mathematical expectation fields and the variance of a stochastic temperature field which is described in the stationary case by a stochastic heat conduction equation and boundary conditions with random coefficients. Random coefficients of the stochastic mathematical model may obey arbitrary truncated distribution laws. An example of using the developed method is presented.Institute of Cybernetics Problems of the Academy of Sciences of USSR, Moscow. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 62, No. 6, pp. 878–885, June, 1992.     

Reduction of nitrite in aged heat transfer media at elevated temperatures

Nitrite is part of many commercially available inhibitor formulations used for corrosion protection in water or water/glycol based heat transfer media in contact with carbon steel. In a heat transfer system of the OMV‐AG used to heat crude oil to lower its viscosity, the nitrite concentration was found to decrease in about three months from 300 ppm to 10 ppm. The system is operated at a maximum temperature of 110°C and 6 bar and an ethylene glycol/water mixture is used as the heat transfer media. An oxidation to nitrate was assumed, but the nitrate concentration was found to be constant. An analysis of the vapor phase present in the system showed next to significant amounts of hydrogen dinitrogen oxide. A possible microbiological infection of the system was investigated, but no bacteria were found. To find the reason for the reduction of nitrite, a laboratory investigation was performed. Stability of nitrite at elevated temperatures and pressure was tested in water and water/glycol mixtures. It was found that nitrite is instable in glycol solutions at temperatures above 120°C. The degradation reaction in aged and unused MEG/water mixtures was compared. An accelerated reduction reaction was found in aged heat transfer media.     

Method of probability analysis of static stochastic temperature fields in technical objects

An efficient method is proposed for calculating the mathematical expectations, the correlation matrix, and the variances of static stochastic temperature fields for complicated technical objects with random parameters and under random conditions. The technical systems are modelled by equivalent electrical circuits with random elements. The method is exact and much more efficient than the Monte Carlo method.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 61, No. 5, pp. 838–844, November, 1991.     

Combining lectin microcolumns with high-resolution separation techniques for enrichment of glycoproteins and glycopeptides

Silica-based lectin microcolumns are described in this study together with the chemical procedures necessary for their preparation. The analytical merits of Canavalia ensiformis and Sambucus nigra lectins, [immobilized on activated macroporous silica], such as binding capacity, trapping reproducibility, and substrate selectivity, have been evaluated using model glycoproteins. The described microcolumns are applicable to high-pressure analytical schemes utilizing microvalving procedures, washing steps, and quantitative desorption for LC/MS analysis. The described analytical systems are amenable to the applications aiming at fractionation of complex glycopeptide mixtures and determination of the sites of glycosylation.     

A Feature Selection Strategy to Optimize Retinal Vasculature Segmentation

Diabetic retinopathy (DR) is a complication of diabetes mellitus that appears in the retina. Clinitians use retina images to detect DR pathological signs related to the occlusion of tiny blood vessels. Such occlusion brings a degenerative cycle between the breaking off and the new generation of thinner and weaker blood vessels. This research aims to develop a suitable retinal vasculature segmentation method for improving retinal screening procedures by means of computer-aided diagnosis systems. The blood vessel segmentation methodology relies on an effective feature selection based on Sequential Forward Selection, using the error rate of a decision tree classifier in the evaluation function. Subsequently, the classification process is performed by three alternative approaches: artificial neural networks, decision trees and support vector machines. The proposed methodology is validated on three publicly accessible datasets and a private one provided by Hospital Sant Joan of Reus. In all cases we obtain an average accuracy above 96% with a sensitivity of 72% in the blood vessel segmentation process. Compared with the state-of-the-art, our approach achieves the same performance as other methods that need more computational power. Our method significantly reduces the number of features used in the segmentation process from 20 to 5 dimensions. The implementation of the three classifiers confirmed that the five selected features have a good effectiveness, independently of the classification algorithm.     

Gender and letters of recommendation for academia: Agentic and communal differences.

In 2 studies that draw from the social role theory of sex differences (A. H. Eagly, W. Wood, & A. B. Diekman, 2000), the authors investigated differences in agentic and communal characteristics in letters of recommendation for men and women for academic positions and whether such differences influenced selection decisions in academia. The results supported the hypotheses, indicating (a) that women were described as more communal and less agentic than men (Study 1) and (b) that communal characteristics have a negative relationship with hiring decisions in academia that are based on letters of recommendation (Study 2). Such results are particularly important because letters of recommendation continue to be heavily weighted and commonly used selection tools (R. D. Arvey & T. E. Campion, 1982; R. M. Guion, 1998), particularly in academia (E. P. Sheehan, T. M. McDevitt, & H. C. Ross, 1998). (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Biocomposites based on poly(lactic acid) and seaweed wastes from agar extraction: Evaluation of physicochemical properties

Seaweed waste (SWW) is a residue or by‐product from the filtration step of the agar extraction process, and it has been explored as an inexpensive and effective filler for incorporation by melt blending into a poly(lactic acid) (PLA) matrix. PLA‐SWW biocomposites were manufactured with various contents of SWW (0, 5, 10, 15, and 20 wt %) using a sheet extrusion process. PLA was functionalized with maleic anhydride (MAH) by reactive extrusion using dicumyl peroxide (DCP) as an initiator, and it was extruded using 0, 5, and 20 wt %. SWW content. The mechanical, thermal, structural, and morphological properties of the processed biocomposites were investigated. Regarding the mechanical behavior, a slight increase in the tensile modulus was observed at low SWW content. The thermal properties indicated that the rigid amorphous phase content was enhanced in the biocomposites. This work suggests that SWW can be used as filler to develop environmental friendly biocomposites. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42320.     

What drives public acceptance of nanotechnology?

How do the risks and benefits of nanotechnology, as viewed by the public, compare with those associated with other technologies such as genetically modified organisms, stem cells, biotechnology and nuclear power? And when deciding to use a specific nanotechnology product, will consumers consider the risks, the benefits, or both? We report the first large-scale empirical analyses of these questions.     

Method of analysis of stochastic nonstationary heat conduction equations

A method is proposed for determination of nonstationary fields of mathematical expectation, second moments, and dispersion of a stochastic nonstationary temperature field for inhomogeneous bodies of an arbitrary form and dimension with arbitrary stochastic boundary conditions.Institute for Cybernetics Problems, Russian Academy of Sciences, Moscow. Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 64, No. 2, pp. 244–251, February, 1993.