Hydrogen reduction kinetics of electrometallurgical slime

The interaction of hydrogen with the zinc-containing electrometallurgical slime of the Severstal’ metallurgical works has been studied. The sequence of transformations in the slime heated to 1100°C in hydrogen or air has been established. The experimental and calculated weight losses coincide. Some of the carbonates are shown to decompose in the temperature range 300–700°C, and most iron and zinc oxides are reduced to a metal. In the temperature range 650–850°C, zinc is almost completely sublimated. At temperatures above 800°C, complex oxides are reduced and calcium and magnesium carbonates and sulfates are likely to decompose. Experimental digital data on the zinc sublimation rate are processed by the least squares method with approximating equations used in thermal analysis. The kinetics of nonisothermal zinc sublimation is comprehensively analyzed using a unique procedure developed for taking into account the background of a peak and the effect of accompanying processes. An equation for the calculation of the zinc sublimation rate under experimental conditions (fluidized bed) is given and tested.     

Tensions in water management: Dutch tradition and European policy.

Present-day worldwide water problems require new management tools and sustainable system innovations. At Delft University of Technology research is being carried out into water resources and management development aimed at forming such tools and innovations, focused on Integrated River Basin Management (IRBM). One of the case-studies deals with Dutch water management and technology in the context of European IRBM in the form of the 2000 Water Frame Directive. The Netherlands experience many water problems and European IRBM could bring help by offering a framework for both international cooperation and technological innovations. To work as an adequate management tool European IRBM should be tailored to the Dutch water tradition, which recently culminated in Integrated Water Management. Both approaches are in some respects contradicting. Europe pursues, for example, centralized control; while the Dutch have their strongly water boards based decentralized administration. The tensions between both approaches require mutual adaptation, for which the concept of subsidiarity might offer points of departure. This paper describes the first results of the case-research into Dutch water management and technology in the context of Europe as well as the backgrounds and the set-up of the research as a whole.     

The effect of the textile industry dye bath additive EDTMPA on colour removal characteristics by ozone oxidation.

In this study, the effects of the phosphonic acid based sequestering agent EDTMPA used in the textile dye baths on colour and organic matter removal by ozone oxidation was experimentally investigated. Procion Navy HEXL dyestuff that has been commonly used for the reactive dyeing of cellulose fibers was selected as the model component. The organic matter oxidation by ozone was determined to obey the pseudo-first order kinetics as they are treated singly or in combination. COD removal rates obtained from pseudo-first order reaction kinetics showed that oxidation of Navy HEXL alone (0.0947 L/min) was faster than that of EDTMPA (0.0171 L/min) and EDTMPA with dye (0.0155 L/min) at pH 3.0. It was also found that reaction rates of single EDTMPA removal and EDTMPA and dye mixture removal increased as the reaction pH was increased from 3.0 to 10.5.     

Some modifications of the classification tree construction algorithm

The paper describes a few modifications of the classification tree construction algorithm that have proved to be useful for solving tasks of noise spectra processing with reference to NPP diagnostics. The article was translated by the authors.     

Characteristics of tunneling and impact ionization in ZnS:Mn-based thin-film electroluminescent structures

A method for measuring the characteristics of tunneling and impact ionization in thin-film electroluminescent emitters is suggested. This method makes it possible to find time dependences of the space-charge layer thickness near the anode and the length of the impact ionization region, to determine more exactly the time dependence of the field in the potential barrier at the cathode interface, the maximum depth of the surface states from which electron tunneling occurs, the minimum thickness of the barrier, and the electron tunneling probability, as well as the impact ionization rate for the deep centers related to structural defects of the phosphor layer.     

Elastic-stress relaxation in heteroepitaxial structures investigated by computer simulation

Atomic mechanisms of elastic-stress relaxation in heteroepitaxial structures are investigated by computer simulation. A 2D model of a heteroepitaxial structure with an empirical interatomic potential is considered. Advanced methods of saddle-point search in a multidimensional space are used to identify main mechanisms of structural change involving the formation of a structural imperfection, and to estimate energy characteristics of the processes.     

Catalytic properties of composite amorphous carbon-platinum layers in fuel cells

Catalytic properties of composite amorphous carbon-platinum layers produced by magnetron cosputtering have been studied. The layers were characterized by electron microscopy, IR spectroscopy, ellipsometry, gravimetry, and spectrophotometric chemical analysis. The catalytic activity of the layers was studied in an air-hydrogen fuel cell by measuring its load and power characteristics.     

Inclusions of carbon in ingots of silicon carbide grown by the modified Lely method

The problem of the appearance of carbon inclusions in single-crystal silicon carbide ingots grown by the modified Lely method (the so-called graphitization of the ingot) is analyzed. It is shown that the process of graphitization of the ingot is not related to a deficit of silicon in the growth cell; in contrast, it is excess of silicon at the growth surface that inhibits the ingot growth rate and gives rise to intense corrosion of the graphite fittings.     

Visual insights into high-resolution earthquake Simulations.

This study focuses on the visualization of a series of large earthquake simulations collectively called TeraShake. The simulation series aims to assess the impact of San Andreas Fault earthquake scenarios in Southern California. We discuss the role of visualization in gaining scientific insight and aiding unexpected discoveries.