783 research outputs found
The development of electrolytes for intermediate temperature solid oxide fuel cells
This report describes a number of experimental studies on the solid state electrolytes for intermediate temperature solid oxide fuel cells (IT-SOFCs): Ce1-xLnxO2-δ (Ln = La, Nd, Sm, Eu, Gd, Dy, Ho, Er, Yb), some multicomponent systems Ce1-xLnx/2Ln x/2O2-δ (x = 0 - 0.20; Ln = Sm, La, Gd and L'n = Dy, Nd, Y), some systems with simultaneous doping by rare earth and alkali earth elements Ce0.8(Sm1-xMx)0.2O2-δ (M = Ca, Sr; x = 0.0 - 1.0) and Ce0.8(Sm1-x-yBayMx)0.2O2-δ (M = Ca, Sr; x = 0, 0.15, 0.20; y = 0.05, 0.1). Two important aspects are emphasized: the effect of different dopants' ionic radius and concentration on the electrical properties of CeO2 based solid solutions and the influence of the method of preparation on the structural properties of ceria ceramics and the electrochemical performance of single SOFCs on their base. To describe the electrolytic properties of solid electrolytes the notation of the electrolytic domain boundary (EDB) - the critical oxygen partial pressure P*O2 at which the values of the electronic and ionic components of conductivity are equal, were calculated and presented. The interpretation of these data will lead to a better understanding of, subsequent improvements to and ultimately, the commercialization of IT-SOFCs in Russia. © 2014 WIT Press.International Journal of Safety and Security Engineering;International Journal of Sustainable Development and Planning;WIT Transactions on Ecology and the Environmen
Specific heat and magnetocaloric effect in Pr1-xAgxMnO3 manganites
The magnetocaloric effect in alternating magnetic fields has been
investigated in Pr1-xAgxMnO3 manganites with x=0.05-0.25. The stepwise reversal
of the sign of the magnetocaloric effect has been revealed in a weakly doped
sample (x=0.05) at low temperatures (~80 K). This reversal is attributed to the
coexistence of the ferromagnetic and canted antiferromagnetic phases with
different critical temperatures.Comment: 4 pages, 4 figure
Proton-He elastic scattering at low energies
We present new accurate measurements of the differential cross section
and the proton analyzing power for proton-He
elastic scattering at various energies. A supersonic gas jet target has been
employed to obtain these low energy cross section measurements. The
distributions have been measured at = 0.99, 1.59,
2.24, 3.11, and 4.02 MeV. Full angular distributions of have been
measured at = 1.60, 2.25, 3.13, and 4.05 MeV. This set of
high-precision data is compared to four-body variational calculations employing
realistic nucleon-nucleon (NN) and three-nucleon (3N) interactions. For the
unpolarized cross section the agreement between the theoretical calculation and
data is good when a potential is used. The comparison between the
calculated and measured proton analyzing powers reveals discrepancies of
approximately 50% at the maximum of each distribution. This is analogous to the
existing `` Puzzle'' known for the past 20 years in nucleon-deuteron
elastic scattering.Comment: 22 pages, 9 figures, to be published in Physical Review C, corrected
reference 4
The fractal method for analysis of macro models of the celestial bodies surface
© 2016, Education and Upbringing Publishing. All rights reserved.In case of building a model of physical surface of celestial body scientists are dealing with a system of parameters whose precision depends on an order of spherical functions series expansion. For significant precision a complicated figure forms and it is almost impossible to describe that with the classical approach. Thereby conducting a comparative analysis of the classical models built on the basis of various observations is quite complicated. The aim of this work is to apply a fractal analysis for topographic and selenographic models investigation. The approach based on fractal similarity of physical structures was used for classical models and models of the librational zone of the Moon, that had been built by expansion in a series of spherical functions in the dynamical coordinate system. As a result, the fractal dimensions of the librational zone of the Moon determined for the mentioned models at various angles have been obtained
Analysis of 430322 lunar occultations
© SGEM2017 All Rights Reserved. In the present work for the first time in the world practice 430322 occultations of stars by the Moon are analyzed. The relevance of the work is that the accuracy analysis of stars' proper motion in modern star catalogues can only be conducted using either observations of small planets or occultations, since only those observations are long-term and homogenous in time. When making the occultation database a comparative analysis has been used to study types and accuracy of occultation. For photoelectric observations were increased weights in this analysis, but only marginally, because the considerable contribution to the errors there are from the catalogue positions of the stars and the corrections for the outline of the Moon. The Russian occultations database has been independently analyzed. The photoelectric occultations database has been analyzed as well. In particular, there is a database of observations of occultations including 225121 objects taken from 1943 to 1980 in Greenwich observatory. But that database does not contain observations of occultations taken in Russia. The number of those observations is 7698. We adjusted this lack. We also keep constructing the full database of occultations using the Internet, printed editions, and data provided by the scientists of National Astronomical Observatory of Japan (NAOJ). As a result, the number of occultation observations was increased to 430322. Approximately 94.3% of those observations are taken by the visual method using telescope of comparatively small aperture. Around 11 % of them were taken by professional astronomers, the rest – by amateurs. About 5.7 % of all the observations are taken by photoelectric method, which implies recording an occultation with an accuracy of 0.001 sec. In conclusion it should be noted that the occultations database is going to be used for studying modern space catalogues, such as Hipparcos, UCAC 4, “Gaia” space mission etc
A solution to the problem of clustered objects compact partitioning
The urgency of the study consists in the fact that an object arrangement topology of a distributed system is often nonuniform. Objects can be placed at different distances from each other, thus forming clusters. That is why solving the problem of compact partitioning into sets containing thousands of objects requires the most effective way to a better use of natural structuring of objects that form clusters. The aim of the study is the development of methods of compact partitioning of sets of objects presented as clusters. The research methods are based on applied theories of sets, theory of compact sets and compact partitions, and linear programming methods with Boolean variables. As a result, the paper offers the method necessary to analyze composition and content of clusters. It also evaluates cluster compactness, which results in the decision to include clusters into the sets of partitions. It addresses the problem of optimizing the rearrangement of objects between compact sets that form clusters, which is based on the criteria of maximizing the total compactness of sets. The problem is formulated in the class of objectives of linear programming methods with Boolean variables. It introduces the example of object rearrangement
The explanation of unexpected temperature dependence of the muon catalysis in solid deuterium
It is shown that due to the smallness of the inelastic cross-section of the
-atoms scattering in the crystal lattice at sufficiently low temperatures
the -mesomolecules formation from the upper state of the hyperfine
structure starts earlier than the mesoatoms thermolization. It
explains an approximate constancy of the -mesomolecule formation rate in
solid deuterium.Comment: 6 pages, 2 jpeg-figure
Computers from plants we never made. Speculations
We discuss possible designs and prototypes of computing systems that could be
based on morphological development of roots, interaction of roots, and analog
electrical computation with plants, and plant-derived electronic components. In
morphological plant processors data are represented by initial configuration of
roots and configurations of sources of attractants and repellents; results of
computation are represented by topology of the roots' network. Computation is
implemented by the roots following gradients of attractants and repellents, as
well as interacting with each other. Problems solvable by plant roots, in
principle, include shortest-path, minimum spanning tree, Voronoi diagram,
-shapes, convex subdivision of concave polygons. Electrical properties
of plants can be modified by loading the plants with functional nanoparticles
or coating parts of plants of conductive polymers. Thus, we are in position to
make living variable resistors, capacitors, operational amplifiers,
multipliers, potentiometers and fixed-function generators. The electrically
modified plants can implement summation, integration with respect to time,
inversion, multiplication, exponentiation, logarithm, division. Mathematical
and engineering problems to be solved can be represented in plant root networks
of resistive or reaction elements. Developments in plant-based computing
architectures will trigger emergence of a unique community of biologists,
electronic engineering and computer scientists working together to produce
living electronic devices which future green computers will be made of.Comment: The chapter will be published in "Inspired by Nature. Computing
inspired by physics, chemistry and biology. Essays presented to Julian Miller
on the occasion of his 60th birthday", Editors: Susan Stepney and Andrew
Adamatzky (Springer, 2017
DBSolve Optimum: a software package for kinetic modeling which allows dynamic visualization of simulation results
<p>Abstract</p> <p>Background</p> <p>Systems biology research and applications require creation, validation, extensive usage of mathematical models and visualization of simulation results by end-users. Our goal is to develop novel method for visualization of simulation results and implement it in simulation software package equipped with the sophisticated mathematical and computational techniques for model development, verification and parameter fitting.</p> <p>Results</p> <p>We present mathematical simulation workbench DBSolve Optimum which is significantly improved and extended successor of well known simulation software DBSolve5. Concept of "dynamic visualization" of simulation results has been developed and implemented in DBSolve Optimum. In framework of the concept graphical objects representing metabolite concentrations and reactions change their volume and shape in accordance to simulation results. This technique is applied to visualize both kinetic response of the model and dependence of its steady state on parameter. The use of the dynamic visualization is illustrated with kinetic model of the Krebs cycle.</p> <p>Conclusion</p> <p>DBSolve Optimum is a user friendly simulation software package that enables to simplify the construction, verification, analysis and visualization of kinetic models. Dynamic visualization tool implemented in the software allows user to animate simulation results and, thereby, present them in more comprehensible mode. DBSolve Optimum and built-in dynamic visualization module is free for both academic and commercial use. It can be downloaded directly from <url>http://www.insysbio.ru</url>.</p
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