Investigation of the rotary swaging and heat treatment on the behavior of W- and γ-phases in PM 92.5W–5Ni–2.5Fe–0.26Co heavy alloy

The effects of rotary swaging and different heat treatment procedures on the W- and γ-phases behavior of PM 92.5W–5Ni–2.5Fe (wt.%) heavy alloy microalloyed with cobalt have been studied. The investigation was performed on sintered and cold rotary swaged samples deformed with area reduction from 5 to 30%. One batch of swaged samples was annealed in vacuum at 1473 K for 7.2 ks and then furnace-cooled to the room temperature, whereas another batch of swaged samples was previously deformed 30% and strain aged in argon and nitrogen in the temperature range between 473 and 1123 K for 3.6 ks. Strengthening of W- and γ-phases was investigated by applying microhardness measurements. Effects of the degree of deformation, parameters of heat treatment and strain aging on microstructural changes have been studied. Mechanical properties, hardness and microhardness of phases as a function of the degree of deformation and heat treatment were analyzed by applying statistical modeling. A correlation between deformation behavior of phases, effect of heat treatment and alloy properties was also discussed.     

Classification of mineral deposits according to the degree of radon release

A classification of mineral deposits according to the degree of radiation hazard for workers in prospecting sections and mining-enrichment combines and the public in adjoining development territories is substantiated on the basis of NRB-99. Four categories of radiation hazardous deposits are identified. The radiation hazard is considered separately for the public, workers in underground sections, and workers in surface production and processing operations. 4 tables, 8 references. A. A. Logachev All-Russia Scientific-Research Institute of Prospecting Geophysics. Translated from Atomnaya énergiya, Vol. 88, No. 6, pp. 438–445, June, 2000.     

Growth of a layer of W6Co7 phase in systems with participation of phases containing cobalt

Growth kinetics for a layer of W₆Co₇ at the interfaces tungsten-cobalt and tungsten-melts based on copper and tin containing cobalt at 1200 °C are studied. It is established that rate constant for growth of this layer in the system with participation of tin (k_Sn) is much greater than in the system with copper (k_Cu). Dependences are determined for these constants on cobalt activity in the melt (a_Co): k_Cu(m²/sec) = = 1.72 · 10^?15(a_Co ? 0.221) + 2.99 · 10^?14 (a_Co ? 0.221)²; k_Sn(m²/sec) = 1.8 · 10^?14 (a_Co ? 0.221) + + 9.077 · 10^?12 (a_Co ? 0.221)³.     

Particle Adhesion to Drops

The adhesion of spheroidal particles to spherical drops is calculated and discussed in terms of an equilibrium-penetration index. The present study emphasizes the case of particles that are sufficiently large to affect the drop volume upon penetration. It is shown that the more elongated the particles, the steeper the dependence of the penetration index on the contact angle. The effect of line tension on nanoscale particles is considered. Positive line tensions increase the steepness of the dependence of penetration index on contact angle whereas negative line tensions decrease this dependence. In addition, the energy barrier caused by positive line tensions is presented and discussed.     

On the spatial distribution of visual attention.

A reanalysis of part of P. Podgorny and R. N. Shepard's (see record 1984-03057-001) data shows that reaction times (RTs) to attended and unattended squares are almost identical when the attended areas are nonunitary and that RTs are related to compactness for unitary attended areas but that this relation breaks down when attention is focused on nonunitary areas. The importance of the actual grid location of probes on RTs is also illustrated. The failure of compactness to reflect these aspects of the spatial nature of attention suggests that this metric is deficient when applied to the study of the spatial determinants of attention. (8 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

The velocity and attenuation of outgoing surface acoustic waves measured using an ultrasonic microscope with two focusing transducers

A new method for measuring the local parameters of outgoing surface acoustic waves (OSAWs) is proposed. The technique employs a system of two focusing transducers, with the output signal taken from one of these scanning over the sample surface. In comparison with the conventional method with a single transducer moving in the direction normal to the sample surface, the proposed technique is capable of conducting measurements in a greater range of OSAW velocities and is less sensitive to parameters of the immersion liquid. The new method was experimentally verified by measuring systems with known properties.     

Carbonization phenomena on dynamic shaft-seals

Carbonization of dynamic shaft-seals is a phenomenon that can result in oil leakage. The cause of carbonization has been studied, and suitable test methods have been developed. This article evaluates the phenomenon, looks at its implications, and provides details of these methods.     

Symmetry and experimental investigation of explosion under hypervelocity impact

Results of the laboratory experimental investigation of the impact against the barriers of a number of materials by the shower of tungsten particles (striker) having density equal to 1 g/cm³, mass equal to 0.2 g and velocity up to 24 km/s as well as their head-on collision with relative velocity equal to 48 km/s, the results of analysis and prediction are presented. By using filming with illuminating from explosive the registration has been realized. Penetration, reactive pulse and the character of energy release during the shower deceleration were studied. In the experiment the process development picture (partial explosion during impact and subsequent penetration) which appeared to be intermediate between the complete explosion of the striker on the surface of the barrier and the explosion in the barrier after penetration has been realized. The hypervelocity collision process is also necessary to consider, to investigate and to develop as a system being possessed of its specific properties. The results presented in the report make possible to predict the explosion parameters for the wide range of strikers and barriers.