Tests of a Two-Stage Core at the KV-1 Test Facility: Physical Aspects and Results

Atomic Energy - The physical aspects and main results of reactor tests of a two-stage core consisting of fresh fuel assemblies and a significant number of fuel assemblies from the previous core,...     

Mathematical Modeling and Optimization of Diesel-Fuel Hydrotreatment

Theoretical Foundations of Chemical Engineering - The main approaches to developing a reactor block for the hydrodesulfurization of diesel fuels are considered taking into account the reactivity of...     

Metall-Matrix-Verbundwerkstoffe auf Eisenbasis

Metal-Matrix-Composites use a reinforcing phase to improve the mechanical properties of the matrix material or achieve a weight reduction. For example in iron and steel industrial applications typically carbides and borides are used to improve wear resistance. The intention of current investigations at the Chair of Metallurgy at the Montanuniversitaet Leoben is to produce a composite with reduced density and consistent or increased stiffness as steel. This paper reviews possible processing routes on steel composites with ceramic reinforcing phases based on a literature survey. A classification of the processing steps based on the origin of the ceramic phase is made and the advantages and disadvantages of these steps are summarized. Two tables are given to present the high amount of possible producing steps and the used investigation techniques for steel-based metal matrix composites.     

Phosphorus-containing compounds of pollucite structure and radiochemical problems

New pollucite-like phosphorus-containing compounds with cesium and uni-, bi-, and trivalent cations (Li; Mg, Mn, Co, Ni, Cu, Zn, Cd, Sr, Ba; Al, Cr, Fe), many of which can be present in various combinations in wastes from radiochemical processes, were synthesized. The individual phases obtained were characterized by X-ray phase analysis and IR spectroscopy. The symmetry of the unit cells of the phosphorus-containing compounds decreases relative to the silicon analog (pollucite natural mineral) from Ia3d to I4₁32. The behavior of the compounds on heating to 1000°C, under hydrothermal conditions at 90°C, in aqueous systems (distilled water and seawater) at 25°C, and in a CsCl melt at 680°C was studied. The chemical and phase composition of the samples remained unchanged under all these conditions. The Cs leaching rates varied from 7.1 × 10⁻⁶ to 1.46 × 10⁻⁵ g cm⁻² day⁻¹. The “crystal-chemical modeling” of the new possible compositions of the compounds with the expected pollucite structure was performed.     

Calculation and experimental evaluation of the service life of welded joints in a nodular graphite cast iron pipeline for mechanical loading conditions. Part I ‐ experimental procedure and material

The main types of flux-cored strip electrode materials for mechanized arc surfacing of alloyed and composite alloys are discussed. Surfacing with these strips results in the formation of the required properties of the working surfaces of components. Special features of the melting and formation of the deposited layer with the required welding and technological properties are also discussed, taking into account the production technology of flux-cored strips.     

Peculiarities of volt-ampere characteristics of a tungsten cathode in a high-current arc

A model making it possible to calculate the emission currents in a cathode and its volt-ampere characteristic (VAC) taking the phenomena in the near-cathode plasma layer into account is proposed. The effect of plasma electrons and ions, thermal field-emission processes, and radiation from the plasma and evaporation of the cathode material are taken into account. The fields of the electrical potential and temperature in the cathode body, with the Joule heat release taken into account, are calculated. The numerical simulation yielded the conditions causing the volt-ampere characteristic ambiguity in the near-cathode layer in the absence of a liquid cathode spot. The obtained characteristics make it possible to estimate the lifetime and efficiency of a plasmotron with a tungsten cathode and argon serving as an actuating medium used in a number of plasma technologies.