2,009 research outputs found
Planning the forest transport systems based on the principles of sustainable development of territories
The article identifies a new method of dynamic modeling in the design of the transport system in the forest fund (TSFF), which is based on economic and mathematical modeling and fuzzy logic tools. The combination of the indicated methods is designed to reduce the disadvantages of their use and increase the benefits. The article substantiates the choice of assessing the forecast level of the impact of risks on the activities of forestry enterprises (the method of expert assessments), using the methodological tools of fuzzy logic. The indicated method makes it possible to take into account a large variety of risk factors of the internal and external environment. At the same time, methodological aspects of fuzzy logic make it possible to formulate a quantitative assessment of qualitative indicators. The article substantiates the choice of tools for economic and mathematical modeling in order to state the design problem of the planned TSFF. Since the indicated method enables the formalization of the functioning of the timber transport system in the given conditions. The article presents a developed model that correctly takes into account the influence of risk factors when planning a TSFF, through the combination of fuzzy logic methods and economic and mathematical modeling. The advantages of the developed model include: considering the multivariance of material flows, vehicles, points of overload, etc.; automated processing of input parameters and effective data; using the model for forecasting, i.e. the possibility of deriving a fuzzy estimate of the efficiency of the timber transport system by identifying cause-effect relationships between the modeling object and the influence of risk factors on its functioning. © 2019 IOP Publishing Ltd
On the possibility of refining by means of optical location some astronomical parameters of the system - Earth-Moon
Optical location of moon in Earth-Moon system using artificial light reflector, on lunar surfac
E2 strengths and transition radii difference of one-phonon 2+ states of 92Zr from electron scattering at low momentum transfer
Background: Mixed-symmetry 2+ states in vibrational nuclei are characterized
by a sign change between dominant proton and neutron valence-shell components
with respect to the fully symmetric 2+ state. The sign can be measured by a
decomposition of proton and neutron transition radii with a combination of
inelastic electron and hadron scattering [C. Walz et al., Phys. Rev. Lett. 106,
062501 (2011)]. For the case of 92Zr, a difference could be experimentally
established for the neutron components, while about equal proton transition
radii were indicated by the data. Method: Differential cross sections for the
excitation of one-phonon 2+ and 3- states in 92Zr have been measured with the
(e,e') reaction at the S-DALINAC in a momentum transfer range q = 0.3-0.6
fm^(-1). Results: Transition strengths B(E2;2+_1 -> 0+_1) = 6.18(23), B(E2;
2+_2 -> 0+_1) = 3.31(10) and B(E3; 3-_1 -> 0+_1) = 18.4(11) Weisskopf units are
determined from a comparison of the experimental cross sections to
quasiparticle-phonon model (QPM) calculations. It is shown that a
model-independent plane wave Born approximation (PWBA) analysis can fix the
ratio of B(E2) transition strengths to the 2+_(1,2) states with a precision of
about 1%. The method furthermore allows to extract their proton transition
radii difference. With the present data -0.12(51) fm is obtained. Conclusions:
Electron scattering at low momentum transfers can provide information on
transition radii differences of one-phonon 2+ states even in heavy nuclei.
Proton transition radii for the 2+_(1,2) states in 92Zr are found to be
identical within uncertainties. The g.s. transition probability for the
mixed-symmetry state can be determined with high precision limited only by the
available experimental information on the B(E2; 2+_1 -> 0+_1) value.Comment: 14 pages, 5 figures, submitted to Phys. Rev. C, revised manuscrip
Consistent alpha-cluster description of the 12C (0^+_2) resonance
The near-threshold 12C (0^+_2) resonance provides unique possibility for fast
helium burning in stars, as predicted by Hoyle to explain the observed
abundance of elements in the Universe. Properties of this resonance are
calculated within the framework of the alpha-cluster model whose two-body and
three-body effective potentials are tuned to describe the alpha - alpha
scattering data, the energies of the 0^+_1 and 0^+_2 states, and the
0^+_1-state root-mean-square radius. The extremely small width of the 0^+_2
state, the 0_2^+ to 0_1^+ monopole transition matrix element, and transition
radius are found in remarkable agreement with the experimental data. The
0^+_2-state structure is described as a system of three alpha-particles
oscillating between the ground-state-like configuration and the elongated chain
configuration whose probability exceeds 0.9
Giant Coulomb broadening and Raman lasing on ionic transitions
CW generation of anti-Stokes Raman laser on a number of blue-green argon-ion
lines (4p-4s, 4p-3d) has been demonstrated with optical pumping from metastable
levels 3d'^2G, 3d^4F. It is found, that the population transfer rate is
increased by a factor of 3-5 (and hence, the output power of such Raman laser)
owing to Coulomb diffusion in the velocity space. Measured are the excitation
and relaxation rates for the metastable level. The Bennett hole on the
metastable level has been recorded using the probe field technique. It has been
shown that the Coulomb diffusion changes shape of the contour to exponential
cusp profile while its width becomes 100 times the Lorentzian one and reaches
values close to the Doppler width. Such a giant broadening is also confirmed by
the shape of the absorption saturation curve.Comment: RevTex 18 pages, 5 figure
Current Status and New Challenges of The Tunka Radio Extension
The Tunka Radio Extension (Tunka-Rex) is an antenna array spread over an area
of about 1~km. The array is placed at the Tunka Advanced Instrument for
cosmic rays and Gamma Astronomy (TAIGA) and detects the radio emission of air
showers in the band of 30 to 80~MHz. During the last years it was shown that a
sparse array such as Tunka-Rex is capable of reconstructing the parameters of
the primary particle as accurate as the modern instruments. Based on these
results we continue developing our data analysis. Our next goal is the
reconstruction of cosmic-ray energy spectrum observed only by a radio
instrument. Taking a step towards it, we develop a model of aperture of our
instrument and test it against hybrid TAIGA observations and Monte-Carlo
simulations. In the present work we give an overview of the current status and
results for the last five years of operation of Tunka-Rex and discuss prospects
of the cosmic-ray energy estimation with sparse radio arrays.Comment: Proceedings of E+CRS 201
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