New Refractories Developed by the Ukrainian Research Institute of Refractories Named after A.S. Berezhnoy

The article gives an introduction to the Ukrainian Research Institute of Refractories and especially its R D and refractory products for the industries of iron and steel,nonferrous,glass and chemistry etc.     

Nano-Blast Synthesis of Nano-size CeO2–Gd2O3 Powders

CeCl₃·7H₂O and GdCl₃·6H₂O that were dissolved in water were precipitated with urea (NH₂CONH₂) to produce matrix agglomerates for three-component nano-reactors. Mixing hexamethylenetetramine with dilute nitric acid resulted in the formation of well-dispersed nano-particles of cyclotrimetilene trinitramine (C₃H₆N₆O₆) (RDX) in the solvent. Nano-reactors were produced by impregnating the nano-C₃H₆N₆O₆ into the matrix agglomerates of an intermediate complex of cerium and gadolinium compounds. Blast initiation of the C₃H₆N₆O₆ resulted in extremely rapid detonation and gaseous products formation at temperatures of 2000°–5000°C, which were compressed into a volume nearly equal to the initial volume of each RDX nano-particle. Multiple "nano-blasts" occurred in the volume of each nano-reactor. The impact of the blast waves led to fragmentation of the surrounding matter. The evolution of a large volume of gaseous products dissipated the heat of the process and limited temperature increase, thus reducing the possibility of local sintering among the primary particles. The short-term high temperature generated during the blasts enhanced the solid solubility of the metal oxides. Uniform aggregates of 22∼74 nm consisting of 6∼14 nm crystallites of gadolinia in ceria solid solution were synthesized.     

Region-based Statistical Analysis of 2D PAGE Images

A new comprehensive procedure for statistical analysis of two-dimensional polyacrylamide gel electrophoresis (2D PAGE) images is proposed, including protein region quantification, normalization and statistical analysis. Protein regions are defined by the master watershed map that is obtained from the mean gel. By working with these protein regions, the approach bypasses the current bottleneck in the analysis of 2D PAGE images: it does not require spot matching. Background correction is implemented in each protein region by local segmentation. Two-dimensional locally weighted smoothing (LOESS) is proposed to remove any systematic bias after quantification of protein regions. Proteins are separated into mutually independent sets based on detected correlations, and a multivariate analysis is used on each set to detect the group effect. A strategy for multiple hypothesis testing based on this multivariate approach combined with the usual Benjamini-Hochberg FDR procedure is formulated and applied to the differential analysis of 2D PAGE images. Each step in the analytical protocol is demonstrated by using an actual dataset. The effectiveness of the proposed methodology is shown using simulated gels in comparison with the commercial software packages PDQuest and Dymension. We also introduce a new procedure for simulating gel images.     

Transformation of Simulink models to IEC 61499 Function Blocks for verification of distributed control systems

In this paper, a new model-based engineering approach is introduced by bridging MATLAB Simulink with IEC61499 Function Block models. This is achieved by a transformation between the two block-diagram languages. The transformation supported by the developed tools sets the cornerstone of the verification and validation framework for IEC 61499 Function Blocks in closed-loop with the models of the plant. The framework also paves the way to running distributed simulations of complex hybrid (i.e., continuous-discrete) closed-loop plant-controller systems and building complex models using the efficient object instantiation techniques of IEC 61499.     

Micro- and macroscopic thermal expansion of stabilized aluminum titanate

The lattice expansion of aluminum titanate (AT) obtained by firing a mixture of alumina, rutile, strontium and calcium carbonate and silica was measured using neutron and laboratory X-ray diffraction. The microscopic data are compared with macroscopic measurement completed by dilatometry.A powder and a compact rod sample were compared to assess the influence of micro residual stresses locked into the solid structure at grain level, which could possibly be relieved upon grinding.Results show good correlation between neutron and X-ray diffraction techniques. They also show that a compact material behaves differently than a powder, contrary to what happens for other porous ceramics such as cordierite. The integrity factor model was used to rationalize the results and predict grain level stresses in all crystal directions and all phases (AT, Strontium aluminum silicate, alumina and residual glass). Calculation show that the AT c-axis is always under compression while all other crystal directions and phases are under tension. Those micro-stresses do not undermine the macroscopic mechanical properties of the material and confer to it its interesting properties like low thermal expansion and enhanced strain tolerance.     

On the thermo-elastostatics of heterogeneous materials: I. General integral equation

We consider a linearly thermoelastic composite medium, which consists of a homogeneous matrix containing a statistically inhomogeneous random set of inclusions, when the concentration of the inclusions is a function of the coordinates (so-called functionally graded materials). The composite medium is subjected to essentially inhomogeneous loading by the fields of the stresses, temperature, and body forces (e.g. for a centrifugal load). The general integral equations connecting the stress and strain fields in the point being considered and the surrounding points are obtained for the random fields of inclusions. The method is based on a centering procedure of subtraction from both sides of a known initial integral equation their statistical averages obtained without any auxiliary assumptions, such as effective field hypothesis implicitly exploited in the known centering methods. In so doing the size of a region including the inclusions acting on a separate one is finite, i.e. the locality principle takes place.     

Ivan Nikitich Frantsevich and His Scientific School

In 2000 there are two dates associated with Ivan Nikitich Frantsevich: his 95th birthday and the 15th anniversary of his death. In that connection, the Frantsevich Institute for Problems of Materials Science has set up a series of lectures in his memory. The materials of those lectures are published in this issue in accordance with the decision of the editorial board.     

Modified track membranes with antibacterial properties

Microbiological contamination of polymeric membranes in the process of their exploitation is an essential problem of membrane technology. It results in the increase of manufacturing costs, destruction of membranes, operating life reduction and secondary contamination of water by the metabolism products of microorganisms. For the purpose of reduction of membrane biofouling and biodegradation investigation of adsorption of the guanidine containing oligomers on the surface of PET track membranes was conducted and their influence on the selectivity and antibacterial properties of the membranes was investigated. It was established that modified membranes have substantially higher resistance to biofouling.