1,576 research outputs found
Pneumatic transportation of dispersed medium through a vertical tube immersed into a fluidized bed
We discuss the technical problem of how to transport granular material in a vertical direction from the underlying section of a multistage apparatus containing a fluidized bed to an upper section through tubes immersed into the fluidized bed without additional expenditures of energy. The intensity with which the dispersed medium (a mixture of gas and fuel particles) moves through the tube and the mass flowrate of particles are determined by the ratio between the hydraulic resistances of dispersed medium inside the tube and of the fluidized bed outside of it. In turn, this ratio depends on the fluidization number W (W = w s/w 0, where w s is the seepage velocity and w 0 is the fluidization commencement velocity) and on the tube immersing depth into the bed. © 2013 Pleiades Publishing, Inc
Atomic, electronic and magnetic structure of graphene/iron and nickel interfaces: theory and experiment
First-principles calculations of the effect of carbon coverage on the atomic,
electronic and magnetic structure of nickel and iron substrates demonstrate
insignificant changes in the interatomic distances and magnetic moments on the
atoms of the metallic substrates. The coverage of the iron surface by mono- and
few-layer graphene induces significant changes in the orbital occupancies and
exchange interactions between the layers in contrast to the case of a nickel
substrate for which changes in the orbital ordering and exchange interactions
are much smaller. Experimental measurements demonstrate the presence of
ferromagnetic fcc-iron in Fe@C nanoparticles and the superparamagnetic behavior
of Ni@C nanoparticles.Comment: 19 pages, 7 figures, accepted to RSC Advance
Kostroma cattle breed in the new century: the state and the prospects (review)
The article reflects the current state and the prospects of the Kostroma cattle breed development. The creation and improvement of the breed anticipated the formation and further breed development in the domestic and world zoo technical science. In recent years, the number of Kostroma cattle breed has been unreasonably reducing despite its economic valuable traits. At the same time in the Kostroma region there are prospects for preserving the valuable gene pool of one of the best domestic dairy and meat cattle breeds. As a result of directed selection and breeding work with the use of Brown Swiss bulls, a stud milk breed "Karavaevsky KK-1" has been developed. At present cow-champions of the Kostroma breed give up to 12,000 kg of milk per lactation. The milk of the Kostroma breed cows has a high content of protein and fat. The animals of Kostroma breed have good meat qualities, high resistance to a number of diseases, strong ungulate horn, easy adaptability to intensive technologies, good fertility and high productive longevity. To save the Kostroma breed it is important to put on 8-10 bulls of 8 planned lines and related groups for the validation and accumulation of sperm every year. The restoration of previously created lines with high genetic potential should be foreseen. It is necessary to identify and actively use the stud bulls bred in their own breeding farms; to conduct a linear assessment of bulls and daughter heifers by body type for more competent selection. In addition to the generally accepted forms and methods of selection, it is necessary to continue immunogenetic control of the authenticity of the origin of breeding animals and introduce modern methods of DNA technology to assess the breeding and productive qualities of cattle, which will reveal valuable genetic complexes in the best breeding animals and thus 1.5-2 times accelerate the selection processes.Conflict of interest: the authors stated that there was no conflict of interest
On the kinetic equation approach to pair production by time-dependent electric field
We investigate the quantum kinetic approach to pair production from vacuum by
time-dependent electric field. Equivalence between this approach and the more
familiar S-matrix approach is explicitly established for both scalar and
fermion cases. For the particular case of a constant electric field exact
solution for kinetic equations is provided and the accuracy of low-density
approximation is estimated.Comment: 8 pages, 4 figure
An improvement of the Berry--Esseen inequality with applications to Poisson and mixed Poisson random sums
By a modification of the method that was applied in (Korolev and Shevtsova,
2009), here the inequalities
and
are proved for the
uniform distance between the standard normal distribution
function and the distribution function of the normalized sum of an
arbitrary number of independent identically distributed random
variables with zero mean, unit variance and finite third absolute moment
. The first of these inequalities sharpens the best known version of
the classical Berry--Esseen inequality since
by virtue of
the condition , and 0.4785 is the best known upper estimate of the
absolute constant in the classical Berry--Esseen inequality. The second
inequality is applied to lowering the upper estimate of the absolute constant
in the analog of the Berry--Esseen inequality for Poisson random sums to 0.3051
which is strictly less than the least possible value of the absolute constant
in the classical Berry--Esseen inequality. As a corollary, the estimates of the
rate of convergence in limit theorems for compound mixed Poisson distributions
are refined.Comment: 33 page
Excitonic instability and electric-field-induced phase transition towards a two dimensional exciton condensate
We present an InAs-GaSb-based system in which the electric-field tunability
of its 2D energy gap implies a transition towards a thermodynamically stable
excitonic condensed phase. Detailed calculations show a 3 meV BCS-like gap
appearing in a second-order phase transition with electric field. We find this
transition to be very sharp, solely due to exchange interaction, and so, the
exciton binding energy is greatly renormalized even at small condensate
densities. This density gradually increases with external field, thus enabling
the direct probe of the Bose-Einstein to BCS crossover.Comment: LaTex, 11 pages, 3 ps figures, To appear in PR
Composition based on aluminum oxide and polydimethylsiloxane matrix for enhancing drug targeting
Methodological approaches developed at Research Institute of Clinical and Experimental Lymphology for a number of years allow formulating the importance of embedding active pharmaceutical ingredients (API) in the structure of porous carriers (sorbents). The composition of the carrier and API is an enteral system for prolonged dosing of pharmacological agents, which allows providing a specific pharmacological effect and safety of use. The pores of the media (sorbents) act as containers for API. This is especially important for rapidly absorbed drugs, which include, for example, lithium preparations that are used in narrow concentration limits due to their side effects. At the moment, an innovative technology for creating new medicines with an improved combination of efficiency and safety (pharmacological upgrade) has been developed and implemented. The essence of the technology is to create a composition of aluminum oxide and polydimethylsiloxane (matrix) and an active pharmacological ingredient (API). A study of two drugs based on matrix / lithium citrate and matrix / melatonin showed continued specific pharmacological activity of API, better pharmacokinetics, and better safety parameters. The matrix of aluminum oxide and polydimethylsiloxane provides an upgrade of the pharmacological properties of drugs for the dosed and safe delivery of API to the zone of their therapeutic effect
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