Investigation of the Ni3Al-Fe alloys by resistivity measurements and differential thermal analysis

A series of iron-doped Ni3Al ternary alloys is investigated by resistivity measurements and differential thermal analysis. Temperatures of phase transformations and disordering onset are determined. A hysteresis phenomenon is observed in the liquid state in polytherms of resistivity upon heating the alloy under study to the critical temperature. © 2013 Allerton Press, Inc

Sewage treatment

The basic function of the wastewater treatment plant is to speed up the natural processes by which water purifies itself. In earlier years, the natural treatment process in streams and lakes was adequate to perform basic wastewater treatment. As our population and industry grew, increased levels of treatment became necessary before discharging domestic wastewater

A numerical study of the influence of channel-scale secondary circulation on mixing processes downstream of river junctions

A rapid downstream weakening of the processes that drive the intensity of transverse mixing at the confluence of large rivers has been identified in the literature and attributed to the progressive reduction in channel scale secondary circulation and shear-driven mixing with distance downstream from the junction. These processes are investigated in this paper using a three-dimensional computation of the Reynolds averaged Navier Stokes equations combined with a Reynolds stress turbulence model for the confluence of the Kama and Vishera rivers in the Russian Urals. Simulations were carried out for three different configurations: an idealized planform with a rectangular cross-section (R), the natural planform with a rectangular cross-section (P), and the natural planform with the measured bathymetry (N), each one for three different discharge ratios. Results show that in the idealized configuration (R), the initial vortices that form due to channel-scale pressure gradients decline rapidly with distance downstream. Mixing is slow and incomplete at more than 10 multiples of channel width downstream from the junction corner. However, when the natural planform and bathymetry are introduced (N), rates of mixing increase dramatically at the junction corner and are maintained with distance downstream. Comparison with the P case suggests that it is the bathymetry that drives the most rapid mixing and notably when the discharge ratio is such that a single channel-scale vortex develops aided by curvature in the post junction channel. This effect is strongest when the discharge of the tributary that has the same direction of curvature as the post junction channel is greatest. A comprehensive set of field data are required to test this conclusion. If it holds, theoretical models of mixing processes in rivers will need to take into account the effects of bathymetry upon the interaction between river discharge ratio, secondary circulation development, and mixing rates

ИССЛЕДОВАНИЕ СПЛАВОВ Ni3Al–Fe МЕТОДАМИ ИЗМЕРЕНИЯ УДЕЛЬНОГО ЭЛЕКТРОСОПРОТИВЛЕНИЯ И ДИФФЕРЕНЦИАЛЬНОГО ТЕРМИЧЕСКОГО АНАЛИЗА

A series of iron-alloyed Ni3Al triple alloys have been investigated by the electrical resistivity measurement and differential thermal analysis. Phase transformation and softening temperatures are found. In heating the investigated alloys to the critical temperature, the hysteresis phenomenon is observed in liquid state in the resistivity polyterms.Методами измерения удельного электросопротивления и дифференциального термического анализа исследована серия тройных сплавов Ni3Al, легированных железом. Определены температуры фазовых превращений и начала разупорядочения. В жидком состоянии на политермах электросопротивления наблюдается явление гистерезиса при нагреве изучаемых сплавов до критической температуры

Subthreshold antiproton production in proton-carbon reactions

Data from KEK on subthreshold antiproton as well as on pi(+-) and K(+-) production in proton-nucleus reactions are described at projectile energies between 3.5 and 12.0 GeV. We use a model which considers a hadron-nucleus reaction as an incoherent sum over collisions of the projectile with a varying number of target nucleons. It samples complete events and allows thus for the simultaneous consideration of all particle species measured. The overall reproduction of the data is quite satisfactory. It is shown that the contributions from the interaction of the projectile with groups of several target nucleons are decisive for the description of subthreshold production. Since the collective features of subthreshold production become especially significant far below the threshold, the results are extrapolated down to COSY energies. It is concluded that an antiproton measurement at ANKE-COSY should be feasible, if the high background of other particles can be efficiently suppressed.Comment: 15 pages, 5 figures, gzipped tar file, submitted to J. Phys. G v2: Modification of text due to demands of referee

Mechanical and technological properties of welded joints produced after plasma cutting

The results of investigations of the mechanical properties of welded joints produced after cutting 09G2N steel by mechanical methods and by plasma torches of different design are presented. It is shown that the impact toughness and static bend strength of the welded joints, produced after plasma cutting without removing the zones of the thermal effect, are not inferior to the parameters obtained after mechanical cutting. In the application of the new single-circuit plasma torch for cutting metals prior to welding, it is possible to produce high-quality welded joints with high productivity and low energy consumption. © 2017 Informa UK Limited, trading as Taylor & Francis Group