314 research outputs found
Equation of state SAHA-S meets stellar evolution code CESAM2k
We present an example of an interpolation code of the SAHA-S equation of
state that has been adapted for use in the stellar evolution code CESAM2k. The
aim is to provide the necessary data and numerical procedures for its
implementation in a stellar code. A technical problem is the discrepancy
between the sets of thermodynamic quantities provided by the SAHA-S equation of
state and those necessary in the CESAM2k computations. Moreover, the
independent variables in a practical equation of state (like SAHA-S) are
temperature and density, whereas for modelling calculations the variables
temperature and pressure are preferable. Specifically for the CESAM2k code,
some additional quantities and their derivatives must be provided. To provide
the bridge between the equation of state and stellar modelling, we prepare
auxiliary tables of the quantities that are demanded in CESAM2k. Then we use
cubic spline interpolation to provide both smoothness and a good approximation
of the necessary derivatives. Using the B-form of spline representation
provides us with an efficient algorithm for three-dimensional interpolation.
The table of B-spline coefficients provided can be directly used during stellar
model calculations together with the module of cubic spline interpolation. This
implementation of the SAHA-S equation of state in the CESAM2k stellar structure
and evolution code has been tested on a solar model evolved to the present. A
comparison with other equations of state is briefly discussed. The choice of a
regular net of mesh points for specific primary quantities in the SAHA-S
equation of state, together with accurate and consistently smooth tabulated
values, provides an effective algorithm of interpolation in modelling
calculations. The proposed module of interpolation procedures can be easily
adopted in other evolution codes.Comment: 8 pages, 5 figure
Anti-corrosion ceramic coatings on the surface of Nd-Fe-B repelling magnets
The results of vacuum-arc deposition of thin ZrO₂coatings to protect the surface of Nd-Fe-B permanent magnets used as repelling devices in orthodontics are presented. The structure, phase composition and mechanical properties of zirconium dioxide films have been investigated by means of SEM, XRD, EDX, XRF and nanoindentation method. It was revealed the formation of polycrystalline ZrO₂ films of monoclinic modification with average grain size 25 nm. The influence of the ZrO₂ coating in terms of its barrier properties for corrosion in quasi-physiological 0.9 NaCl solution has been studied. Electrochemical measurements indicated good barrier properties of the coating on specimens in the physiological solution environment
СОВРЕМЕННОЕ СОСТОЯНИЕ И ПРОБЛЕМы ОБОГАЩЕНИЯ ТИТАНОЦИРКОНИЕВОГО СыРЬЯ В УКРАИНЕ
В природе известно 70 минералов, в различных количествах содержащих титан. На сегодняшний день промышленными источниками титанового сырья являются месторождения, содержащие ильменит, рутил, лейкоксен и, в послед-нее время, анатаз. Львиная (около 90%) часть ильменитовых, лейкоксеновых и рутиловых концентратов используются для производства диоксида титана. Из ильменитовых концентратов получают синтетический рутил и титановые шла-ки, которые можно использовать как для производства губчатого титана, так и диоксида титана. На производство металлического титана используется 7-10% сырья. Природный рутил, кроме того, используется частично и для обмазки сварочных электродов. Наиболее богатыми по содержанию диоксида титана являются рутиловые концентраты (93-96%), ильменитовые содержат 44-70% диоксида титана, а концентраты из лейкоксеновых руд содержат до 90% TiO
The Role of Birds as Potential Reservoirs of West Nile Virus in the Territory of the Russian Federation
Submitted are the materials on epizootiology of West Nile Fever in birds, taking into account their migration. Described are the characteristics of WNF in wild and synanthropic birds. Ecological relationships between birds, mosquitoes, ticks and West Nile virus are analyzed. Main autumn bird migratory directions are characterized and the data on WNF monitoring in birds in different geographical regions of Russia are presented
Electroproduction, photoproduction, and inverse electroproduction of pions in the first resonance region
Methods are set forth for determining the hadron electromagnetic structure in
the sub--threshold timelike region of the virtual-photon ``mass'' and
for investigating the nucleon weak structure in the spacelike region from
experimental data on the process at low energies. These
methods are formulated using the unified description of photoproduction,
electroproduction, and inverse electroproduction of pions in the first
resonance region in the framework of the dispersion-relation model and on the
basis of the model-independent properties of inverse electroproduction.
Applications of these methods are also shown.Comment: The revised published version; Revtex4, 18 pages, 6 figure
Longitudinal Momentum Fraction X_L for Two High P_t Protons in pp->ppX Reaction
We present an analysis of new data from Experiment E850 at BNL. We have
characterized the inclusive cross section near the endpoint for pp exclusive
scattering in Hydrogen and in Carbon with incident beam energy of 6 GeV. We
select events with a pair of back-to-back hadrons at large transverse momentum.
These cross sections are parameterized with a form
, where is the ratio of the longitudinal momentum
of the observed pair to the total incident beam momentum. Small value of
may suggest that the number of partons participating in the reaction is large
and reaction has a strong dependence on the center-of-mass energy. We also
discuss nuclear effects observed in our kinematic region.Comment: 4 pages, 2 figures, to be published in Proceedings of CIPANP2000,
Quebec, May 22-28, 2000, requires aipproc.sty(included
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