Semiclassical trajectory-coherent states of the nonlocal Gross-Pitaesvkii equation with radial symmetry

In this paper the semiclassical formalism is applied to the nonlocal Gross-Pitaevskii equation with radial symmetry. Some aspects of constructing of semiclassically concentrated solutions in polar coordinates are shown. The semiclassical trajectory-coherent states, concentrated on the ring, are obtained. The example of specific physically motivated equation is considered and some properties of its semiclassical trajectorycoherent states are noted

Phase transformations in mechanically alloyed Al-Cu-Cr powders

Mechanical alloying was used to form a decagonal phase in the Al-Cu-Cr system. Elemental powders of Al67Cu20Cr13, Al75Cu10Cr15, Al65Cu24Cr11, Al69Cu21Cr10 and Al78Cu10Cr12 compositions (in at. %) were mechanically alloyed in a planetary ball mill. Annealing in the temperature range of 500 to 550 0C results in the formation of binary and ternary compounds including the decagonal quasicrystalline phase that was found to be stable at least up to 800 0C and was present in various amounts in all investigated alloys. No icosahedral quasicrystalline phase was found in the samples. The maximum content (95 vol. %) of decagonal quasicrystalline phase was observed for Al69Cu21Cr10 compound annealed at 635 0С. Further increase in the annealing temperature results in the quasicrystalline phase transformation into ψ-Al65Cu25Cr10 phase, which is an approximant phase to icosahedral quasicrystal

Structure and magnetic properties of mechanically alloyed Fe3-xAlCrx powders

Mixtures of elemental powders of Fe3-xAlCrx composition, where x ∈ (0.8 -1.2) were mechanically alloyed in the AGO-2U planetary ball mill. Obtained powders consist of particles with median size of 0.5-1.6 µm; increase in the Cr content results in the decrease in the size of particles. According to the X-ray data, all of the as-milled alloys possess a single-phase disordered b.c.c. structure. Increase in Cr content results in the decrease in the grain size of alloys, whereas the dependence of the lattice parameter on the chemical composition is not conclusive. Mössbauer spectra for most of the alloys shows that iron atoms in this alloys, in spite of the fact that only one phase was detected using the X-ray diffraction, exist both in ferromagnetic and non-ferromagnetic conditions

Ball milling effect on the properties of ultra high molecular weight Polyethylene - bronze composite

Peculiarities of the technology to produce a composite material based on ultra-high molecular weight polyethylene (UHMWPE), mechanically activated with bronze powder are considered along with the properties of the produced material. Samples of the press-composition on the basis of UHMWPE with 0 up to 97.5% of the bronze powder addition were prepared by joint mechanoactivation of super-high-molecular polymer and the bronze powder using planetary mechanoactivator MPF-1 and toroidal vibration mechanoactivator MV-0.05. Packed density of the press-composition was analyzed as a function of the formula and the mechanoactivation technique used. Bulk samples for the tests were obtained by direct pressing. The properties of the samples were studied, and the relations between the density of the material, the physical and mechanical and thermal-physical properties and the concentration of the bronze powder in the material and the milling time were investigated

Structure and propertties of ball milled utrahigh-molecular weight Polyethylene - clay composite

In this work the composite material based on polymer matrix filled with clay is studied. The preparation of powder composition consists of mechanical activation of substances and further common ball milling of polymer and clay in a high energy planetary ball mill. The process is divided into two stages; the first stage involves crushing of clay to obtain a nanosized powder, and in the second stage preparation of powdered nanocomposite is carried out. New clay-polymer composite shows considerable increase in modulus of elasticity and a decrease in coefficient of friction

Reinforced Polymer Composites

The development of modern technology requires the elaboration of new materials with improved operational and technological properties [...

Reinforced Polymer Composites III

The development of modern technology requires the development of new materials with improved operational and technological properties [...

Mechanical Alloying of Al73Cu11Cr16Al_{73}Cu_{11}Cr_{16} Alloy from Ion Irradiated Powders

$Al_{73}Cu_{11}Cr_{16}$ alloys were prepared by mechanical alloying of the irradiated by $Ar^{+}$ ions elemental powders. Evolution of alloy structure at ball milling, as well as during the further annealing, was investigated using X-ray diffraction and differential scanning calorimetry. It was shown that ball milling leads to the Cu dissolution in Al and Cr and to the formation of $Al_{2}Cu$ intermetallic phase. An increase of the milling duration leads to an increase of the $Al_{2}Cu$ phase content in the samples. Ion irradiation of initial elemental powders results in an increase of their interaction rate at milling. In the case of irradiated powders using as initial materials, a content of $Al_{2}Cu$ phase after milling is higher than in the case of using non-irradiated elemental powders. No effect of irradiation of initial elemental powders on the phase transformation at heating was observed. The annealing results in the decomposition of Al- and Cr-based supersaturated solid solutions. An increase in the $Al_{2}Cu$ phase content at heating was observed only in the samples, which were milled for 4 h. In the samples milled for 14 h, nearly no increase in $Al_{2}Cu$ phase content at heating was observed. Heating up to 500-600°C results in the single-phase decagonal quasicrystalline phase formation for all of the studied samples

Effect of Graphite Filler Type on the Thermal Conductivity and Mechanical Behavior of Polysulfone-Based Composites

The goal of this study was to create a high-filled composite material based on polysulfone using various graphite materials. Composite material based on graphite-filled polysulfone was prepared using a solution method which allows the achievement of a high content of fillers up to 70 wt.%. Alongside the analysis of the morphology and structure, the thermal conductivity and mechanical properties of the composites obtained were studied. Structural analysis shows how the type of filler affects the structure of the composites with the appearance of pores in all samples which also has a noticeable effect on composites’ properties. In terms of thermal conductivity, the results show that using natural graphite as a filler gives the best results in thermal conductivity compared to artificial and expanded graphite, with the reduction of thermal conductivity while increasing temperature. Flexural tests show that using artificial graphite as a filler gives the composite material the best mechanical load transfer compared to natural or expanded graphite