Metallurgical Technologies and Problems Related to Self-Disposal of Radioactive Waste by Deep Rock Melting

Radioactive waste arranged inside the container releases heat as a result of radioactive decay. If the heat power is sufficient, the geological rock near the container melts and the container moves into the Earth's depths. This method of self-immersion of radioactive waste may be suggested as an additional method to the deep geological disposal approach. The basic problem of method realization is to find a container material that remains firm in a temperature of about 1300–1400°C in melted rock (for example basalt). This problem is considered in connection with the question of radioactive matrix choice and compatibility of materials.     

Chromium electroplating from sulfate-oxalate solutions containing nanoparticles of alumina and silicon carbide

The effect of the introduction of Al₂O₃ and SiC particles into the base chrome-plating sulfate-oxalate Cr (III) bath on the electrochemical characteristics of chromium deposition, as well as the structure and mechanical properties of deposits, is studied. It is shown that Al₂O₃ particles are incorporated only into the surface film and are not detected in the bulk of the coating. Particles SiC are incorporated into both the surface film and the deposit. Introducing the particles into the bath makes the cathode polarization at a fixed current density, as well as the current efficiency and the bath throwing power, increase. Original Russian Text ? E.N. Lubnin, N.A. Polyakov, Yu.M. Polukarov, 2007, published in Zashchita Metallov, 2007, Vol. 43, No. 2, pp. 199–206.     

The limits and pattern of the onset of the effect of thermogravitation on the flow and heat transfer in pipes

The available recommendations and solution of the problem on heat transfer under conditions of turbulent flow of liquid metal in a horizontal pipe with a low effect of thermogravitation are refined, and relations are suggested for the calculation of the onset of the effect of lifting forces on heat transfer under conditions of laminar and turbulent flows of liquid metals, gases, and dropping liquids in horizontal and vertical pipes.     

Effect of various adsorbates on electronic states of the thin diamond-like carbon films

The influence of the adsorbed impurity molecules onto energy spectrum of electronic states of the DLC films deposited on SiO₂/Si substrates by direct ion beam from hydrocarbon IC plasma was studied by charge-based deep level transient spectroscopy (Q-DLTS). The strong sensitivity of Q-DLTS spectra to the presence of the vapor water and alcohol at room temperature was found. The principle is that adsorption of any molecules on the surface of the DLC film results in a change of energy spectrum of the electronic states (or trapping centers) at the DLC film surface. For example, a new peak appeared in Q-DLTS spectra in presence of the vapor water and electron state density increased in several orders. Moreover, the effect of different adsorbed molecules (species) on the surface electron states was different and independent, so that different molecules can be detected separately. It was shown to differentiate a few thousand molecules of virtually any impurity adsorbed by DLC film's surface. Such strong surface phenomena of the thin DLC films may be exploited in novel sensitive and selective chemical sensor devices.     

Porosity dependence of the internal friction and elastic characteristics of iron powder

We have experimentally investigated the internal friction Q^–1 and the elastic characteristics of iron powder with different porosities. We have determined the porosity dependence of the Q^–1 value, the shear modulus, and Young's modulus. We compare the experimental data with the calculation results.Altai University, Varnaul. Translated from Poroshkovaya Metallurgiya, Nos. 3–4, pp. 91–92, March–April, 1994.     

Corrosion cracking of welded joints in low-alloy steels in a hydrogen sulfide-bearing medium

Translated from Fiziko-Khimicheskaya Mekhanika Materialov, No. 5, pp. 39–43, September–October, 1992.     

Electrical and luminescent properties and the spectra of deep centers in GaMnN/InGaN light-emitting diodes

Electrical and electroluminescent properties were studied for GaN/InGaN light-emitting diodes (LEDs) with the n-GaN layer up and with the top portion of the n layer made of undoped GaMnN to allow polarization modulation by applying an external magnetic field (so-called “spin-LEDs”). The contact annealing temperature was kept to 750°C, which is the thermal stability limit for retaining room-temperature magnetic ordering in the GaMnN layer. Measurable electroluminescence (EL) was obtained in these structures at threshold voltages of ∼15 V, with a lower EL signal compared to control LEDs without Mn. This is related to the existence of two parasitic junctions between the metal and the lower contact p-type layer and between the GaMnN and the n-GaN in the top contact layer.     

Noncontact methods of studying the parameters of particles in two-phase plasma flows

Journal of Engineering Physics and Thermophysics -