Statistical analysis of operational reliability for electric pump units CN 60–180 of VVER-1000 reactors with root estimation methods

We consider the problem of processing statistical data obtained during the operation of pumping units CN 60–180 operating as standard equipment of the VVER-1000 reactors. Data for analysis was taken from the industry database of VNIIAES. The objects’ operation has been observed from January 1, 1990 to December 31, 2007. Statistical information is processed with nonparametric estimation method called root estimation. We obtain reliability characteristics for the units: time-to-failure density and distribution function, faultless operation probability, and fault intensity. The obtained results are used to determine control influences.     

Characterization of functionalized multiwalled carbon nanotubes and application as an effective filter for heavy metal removal from aqueous solutions☆

Filtration efficiency of Ni(II) from aqueous solution using pristine and modified MWCNTs filters was investigated as a function of Ni(II) ion concentration, pH, and filter mass. MWCNTs were synthesized by CVD method and modified using two complementary treatments, purification (using a mixture of hydrochloric acid and hydrogen peroxide) and functionalization (using nitric acid). The effect and mechanism of each treatment on the structural integrity of pristine MWCNTs has been studied. Morphology of the pristine and modified filters was investigated by Raman Spectrometry (RS), Scanning Electron Microscopy (SEM), Energy Dispersive X-ray Spectroscopy (EDS), Fourier Transform Infrared (FTIR) spectrometry and Thermogravimetric analysis. It was found from Raman spec-tra that the ratio of the intensity of D-band to that of G-band decreased by purification process, and increased by functionalization process. The adsorption mechanism of Ni(II) onto the surface functional groups of modified MWCNTs was confirmed by FTIR spectrum. The filtration results showed that the removal efficiency of Ni(II) is strongly dependent on pH and could reach 85%at pH=8. Also, modified MWCNT filters can be reused through many cycles of regeneration with high performance. Functionalized MWCNTs filters may be a promising adsor-bent candidate for heavy metal removal from wastewater.     

Electrorheological behavior of low filled suspensions of highly anisometric montmorillonite particles

The electrorheological (ER) behavior of modified montmorillonite (MMT) suspensions in polydimethylsiloxane is studied. As established by rotational viscometry, the samples with a dispersed phase concentration from 1 to 8 wt % reveal viscous Newtonian behavior and dramatically change their properties to elastic when electric field is applied. The rheological characteristics of the suspensions over 0–7 kV mm⁻¹ range of electric field strengths are also studied. Novel X-ray diffraction method is developed to evaluate the suspension of the filler in a siloxane medium and to calculate the degree of its exfoliation. The dependence of exfoliation degree, dielectric, and ER characteristics on the type of modifier in the MMT structure is considered. Based on the obtained data, a new model of system behavior with the various types of fillers is proposed and the prospects of utilizing MMT as a filler for ER fluids are demonstrated. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 47678.     

Effective thermal diffusivity of a vibrationally fluidized bed

Studies have been made on the effective thermal diffusivity in an extended vibrationally fluidized bed with or without a set of vertical tubes.Translated from Inzhenerno-Fizicheskii Zhurnal, Vol. 58, No. 4, pp. 610–618, April 1990.     

Effect of orientation stretch on structure of a composite fibre based on high-density polyethylene and polybutylene terephthalate

Conclusions Due to the effect of the HDPE matrix in composite fibres based on HDPE-PBTP it is possible to draw the polybutylene terephthalate component to degrees of orientation which exceed the degree of orientation attained for pure PBTP.The introduction of chemical cross-links between the HDPE and the PBTP under radiative treatment permits one to expand the temperature service range of polyethylene fibres containing a small amount of the polyester.The possibility of transition from orthorhombic chain packing to a mesomorpohic state in a HDPE composite fibre on heating above the equilibrium melting point under isometric conditions has been demonstrated.Translated from Khimicheskie Volokna, No. 5, pp. 33–35, September–October, 1989.