102 research outputs found
Thermodynamic modeling of the Pb + Bi melt evaporation under various pressures and temperatures
The composition of the vapor phase and the partial pressures of vapor components have been defined at pressures from 102 to 107 Pa and in the temperature range from 500 to 3000 K. Diagrams of liquid-vapor phase equilibria for the Pb-Bi system have been constructed. A good agreement between experimental results and the carried out calculations on the Pb-Bi phase diagrams is observed. © 2012 Elsevier B.V. All rights reserved
POST-EVALUATION AND ESTIMATE OF RADIOACTIVE WASTE FORMATION DURING NORMAL OPERATION OF RUSSIAN NUCLEAR POWER PLANTS
This work demonstrates the possibility of using the specific indicator of radioactive waste generation per unit of generated electricity (m3/GWh) for retrospective assessment and fore-casting of the volume of radioactive waste generation at Russian nuclear power plants
Individual and Multi Vortex Pinning in Systems with Periodic Pinning Arrays
We examine multi and individual vortex pinning in thin superconductors with
periodic pinning arrays. For multi-vortex pinning we observe peaks in the
critical current of equal magnitude at every matching field, while for
individual vortex pinning we observe a sharp drop in the critical current after
the first matching field in agreement with experiments. We examine the scaling
of the critical current at commensurate and incommensurate fields for varied
pinning strength and show that the depinning force at incommensurate fields
decreases faster than at the commensurate fields.Comment: 4 figuure
Environmental potential analysis of co-processing waste in cement kilns
Технологiя спiльного спалення вiдходiв у цементних печах зарекомендувала себе надiйним, ефективним та зручним методом утилiзацiї вiдходiв (побутових та промислових). Проте країни по всьому свiту зiштовхуються з наступними ключовими бар'єрами на шляху до впровадження технологiї сумiсної переробки вiдходiв у цементних печах: нечiтке законодавство, вiдсутнiсть фiнансової пiдтримки, сприйняття громадськiстю, тощо. Цi бар'єри можуть бути частково усунутi за допомогою заходiв, запропонованих у цьому дослiдженнi.The technology of waste co-processing in cement kilns has proven to be a reliable, efficient and convenient method of waste disposal (domestic and industrial). However, countries around the world face the following key barriers to the implementation of the technology of waste co-processing in cement kilns: fuzzy legislation, lack of financial support, public acceptance, etc. These barriers can be partially eliminated by the measures proposed in this study. In addition, waste sorting and processing are often not carried out systematically. National and international cement companies operate modern cement kilns which could substitute a part of their fossil fuel and raw material with suitable waste streams to be co-processed. Co-processing non-recyclable waste is often a valid option to close loops towards circular economy. This technology is widely used in different European countries, but with different environmental impacts. Therefore, it is important to investigate the environmental potential of this technology, which is variable for different waste morphology conditions
Commensurate and Incommensurate Vortex Lattice Melting in Periodic Pinning Arrays
We examine the melting of commensurate and incommensurate vortex lattices
interacting with square pinning arrays through the use of numerical
simulations. For weak pinning strength in the commensurate case we observe an
order-order transition from a commensurate square vortex lattice to a
triangular floating solid phase as a function of temperature. This floating
solid phase melts into a liquid at still higher temperature. For strong pinning
there is only a single transition from the square pinned lattice to the liquid
state. For strong pinning in the incommensurate case, we observe a multi-stage
melting in which the interstitial vortices become mobile first, followed by the
melting of the entire lattice, consistent with recent imaging experiments. The
initial motion of vortices in the incommensurate phase occurs by an exchange
process of interstitial vortices with vortices located at the pinning sites. We
have also examined the vortex melting behavior for higher matching fields and
find that a coexistence of a commensurate pinned vortex lattice with an
interstitial vortex liquid occurs while at higher temperatures the entire
vortex lattice melts. For triangular arrays at incommensurate fields higher
than the first matching field we observe that the initial vortex motion can
occur through a novel correlated ring excitation where a number of vortices can
rotate around a pinned vortex. We also discuss the relevance of our results to
recent experiments of colloidal particles interacting with periodic trap
arrays.Comment: 8 figure
Floating marine macro litter in the Black Sea: Toward baselines for large scale assessment
The Black Sea is a semi-enclosed basin subject to major anthropogenic pressures, including marine litter and plastic pollution. Due to numerous large rivers draining into the basin and a population settled along the coast, the region could accumulate significant amounts of floating litter over time. Until now, only limited field data were available, and litter quantities and distribution remained unknown. In this study, floating marine macro litter (FMML) was assessed at the regional Black Sea scale for the first time, showing relatively high litter densities across the basin that reached a weighted mean of 81.5 items/km(2). Monitoring data revealed an accumulation of floating items offshore in the eastern part of the basin, resembling on a small scale a "garbage patch', where litter items were trapped, showing elevated densities in comparison to their surrounding areas. Most of these items were made of plastic materials (ca. 96%) and included large numbers of plastic and poly-styrene fragments of small size ranges (2.5-10 cm). Harmonised field data collection through consistent and regular monitoring programmes across the region is essential to establish baselines and thresholds for large scale assessment at international level
Order in driven vortex lattices in superconducting Nb films with nanostructured pinning potentials
Driven vortex lattices have been studied in a material with strong pinning,
such as Nb films. Samples in which natural random pinning coexists with
artificial ordered arrays of defects (submicrometric Ni dots) have been
fabricated with different geometries (square, triangular and rectangular).
Three different dynamic regimes are found: for low vortex velocities, there is
a plastic regime in which random defects frustrate the effect of the ordered
array; then, for vortex velocities in the range 1-100 m/s, there is a sudden
increase in the interaction between the vortex lattice and the ordered dot
array, independent on the geometry. This effect is associated to the onset of
quasi long range order in the vortex lattice leading to an increase in the
overlap between the vortex lattice and the magnetic dots array. Finally, at
larger velocities the ordered array-vortex lattice interaction is suppresed
again, in agreement with the behavior found in numerical simulations.Comment: 8 text pages + 4 figure
Critical Currents and Vortex States at Fractional Matching Fields in Superconductors with Periodic Pinning
We study vortex states and dynamics in 2D superconductors with periodic
pinning at fractional sub-matching fields using numerical simulations. For
square pinning arrays we show that ordered states form at 1/1, 1/2, and 1/4
filling fractions while only partially ordered states form at other filling
fractions, such as 1/3 and 1/5, in agreement with recent imaging experiments.
For triangular pinning arrays we observe matching effects at filling fractions
of 1/1, 6/7, 2/3, 1/3, 1/4, 1/6, and 1/7. For both square and triangular
pinning arrays we also find that, for certian sub-matching fillings, vortex
configurations depend on pinning strength. For weak pinning, ordering in which
a portion of the vortices are positioned between pinning sites can occur.
Depinning of the vortices at the matching fields, where the vortices are
ordered, is elastic while at the incommensurate fields the motion is plastic.
At the incommensurate fields, as the applied driving force is increased, there
can be a transition to elastic flow where the vortices move along the pinning
sites in 1D channels and a reordering transition to a triangular or distorted
triangular lattice. We also discuss the current-voltage curves and how they
relate to the vortex ordering at commensurate and incommensurate fields.Comment: 14 figure
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