2,671 research outputs found
Using of the analog complexing of parameters of space-temporal distribution of the EAS Cherenkov light for the analysis of the mass composition of cosmic rays
Precise determination of muon and electromagnetic shower contents from shower universality property
We consider two new aspects of Extensive Air Shower development universality
allowing to make accurate estimation of muon and electromagnetic (EM) shower
contents in two independent ways. In the first case, to get muon (or EM) signal
in water Cherenkov tanks or in scintillator detectors it is enough to know the
vertical depth of shower maximum and the total signal in the ground detector.
In the second case, the EM signal can be calculated from the primary particle
energy and the zenith angle. In both cases the parametrizations of muon and EM
signals are almost independent on primary particle nature, energy and zenith
angle. Implications of the considered properties for mass composition and
hadronic interaction studies are briefly discussed. The present study is
performed on 28000 of proton, oxygen and iron showers, generated with CORSIKA
6.735 for spectrum in the energy range log(E/eV)=18.5-20.0 and
uniformly distributed in cos^2(theta) in zenith angle interval theta=0-65
degrees for QGSJET II/Fluka interaction models.Comment: Submitted to Phys. Rev.
The crystallization of thin Sb2Te films with vacuum annealing and an electron beam
Thin Sb2Te films with a thickness gradient were studied via transmission electron microscopy. The processes of forced crystallization were examined with thermal annealing and an electron beam. The crystallization’s general tendencies, including competitive nucleation and growth crystallization, were revealed. As the thickness of the sample increases, the size of the crystals growing in the film enlarges. As the temperature increases, the number of crystals in the film grows. Crystallization under the action of an electron beam occurs mainly by nucleation mechanism
A New Method of Vibration Analysis of Elastic Systems, Based on the Lagrange Equations of the First Kind
 
Recrystallization and investigation of bismuth thin films by means of electron beam in transmission electron microscope
Thin bismuth films obtained by vacuum deposition were recrystallized under electron beam of scanning electron microscope at 5 kV and examined in a transmission electron microscope at 200 kV. In recrystallized films, various microstructures were detected: single-crystal, polycrystalline and amorphous regions, more or less faceted grains, single crystals and untransparent drop-shaped particles. In the crystallized film, a strong internal bending of the crystal lattice is detected, up to 110 deg/μm. © Published under licence by IOP Publishing Ltd.Partial support of project 3.6121.2017/8.9 (The Ministry of Education and Science of the Russian Federation) and Agreement No 02.A03.21.0006 (Act 211 Government of the Russian Federation) is acknowledged
HEPPA-II model-measurement intercomparison project: EPP indirect effects during the dynamically perturbed NH winter 2008-2009
Funke, B. et. al..--This work is distributed under the Creative Commons Attribution 3.0 License.We compare simulations from three high-top (with upper lid above 120 km) and five medium-top (with upper lid around 80 km) atmospheric models with observations of odd nitrogen (NOx D NO+NO2), temperature, and carbon monoxide from seven satellite instruments (ACE-FTS on SciSat, GOMOS, MIPAS, and SCIAMACHY on Envisat, MLS on Aura, SABER on TIMED, and SMR on Odin) during the Northern Hemisphere (NH) polar winter 2008/2009. The models included in the comparison are the 3-D chemistry transport model 3dCTM, the ECHAM5/MESSy Atmospheric Chemistry (EMAC) model, FinROSE, the Hamburg Model of the Neutral and Ionized Atmosphere (HAMMO-NIA), the Karlsruhe Simulation Model of the Middle Atmosphere (KASIMA), the modelling tools for SOlar Climate Ozone Links studies (SOCOL and CAO-SOCOL), and the Whole Atmosphere Community Climate Model (WACCM4). The comparison focuses on the energetic particle precipitation (EPP) indirect effect, that is, the polar winter descent of NOx largely produced by EPP in the mesosphere and lower thermosphere. A particular emphasis is given to the impact of the sudden stratospheric warming (SSW) in January 2009 and the subsequent elevated stratopause (ES) event associated with enhanced descent of mesospheric air. The chemistry climate model simulations have been nudged toward reanalysis data in the troposphere and stratosphere while being unconstrained above. An odd nitrogen upper boundary condition obtained from MIPAS observations has further been applied to medium-top models. Most models provide a good representation of the mesospheric tracer descent in general, and the EPP indirect effect in particular, during the unperturbed (pre-SSW) period of the NH winter 2008/2009. The observed NOx descent into the lower mesosphere and stratosphere is generally reproduced within 20 %. Larger discrepancies of a few model simulations could be traced back either to the impact of the models' gravity wave drag scheme on the polar wintertime meridional circulation or to a combination of prescribed NOx mixing ratio at the uppermost model layer and low vertical resolution. In March-April, after the ES event, however, modelled mesospheric and stratospheric NOx distributions deviate significantly from the observations. The too-fast and early downward propagation of the NO x tongue, encountered in most simulations, coincides with a temperature high bias in the lower mesosphere (0.2-0.05 hPa), likely caused by an overestimation of descent velocities. In contrast, upper-mesospheric temperatures (at 0.05-0.001 hPa) are generally underestimated by the high-top models after the onset of the ES event, being indicative for too-slow descent and hence too-low NOx fluxes. As a consequence, the magnitude of the simulated NOx tongue is generally underestimated by these models. Descending NOx amounts simulated with mediumtop models are on average closer to the observations but show a large spread of up to several hundred percent. This is primarily attributed to the different vertical model domains in which the NOx upper boundary condition is applied. In general, the intercomparison demonstrates the ability of state-of- the-art atmospheric models to reproduce the EPP indirect effect in dynamically and geomagnetically quiescent NH winter conditions.
The encountered differences between observed and simulated NOx, CO, and temperature distributions during the perturbed phase of the 2009 NH winter, however, emphasize the need for model improvements in the dynamical representation of elevated stratopause events in order to allow for a better description of the EPP indirect effect under these particular conditions.This work has been conducted in the frame of the WCRP/ SPARC SOLARIS-HEPPA activity. The IAA team was supported by the Spanish MCINN under grant ESP2014-54362-P and EC FEDER funds. The MPI-MET team was supported by the Max Planck Gesellschaft (MPG), and computational resources were made available by Deutsches Klimarechenzentrum (DKRZ) through support from Bundesministerium fur Bildung und Forschung (BMBF). The FMI team was supported by the Academy of Finland through the projects 276926 (SECTIC: Sun-Earth Connection Through Ion Chemistry), 258165, and 265005 (CLASP: Climate and Solar Particle Forcing). CAO team was supported by the Russian Science Foundation under grant 15-17-10024. SOCOL team was funded by Swiss National Science Foundation (SNSF) grants 200021-149182 (SILA), 200020-163206 (SIMA), and CRSII2-147659 (FUPSOL-II). S. Bender, M. Sinnhuber, and H. Nieder (all KIT) gratefully acknowledge funding by the Helmholtz Association of German Research Centres (HGF), grant VH-NG-624. NCAR is sponsored by the National Science Foundation (NSF). Computing resources for WACCM simulations were provided by the Climate Simulation Laboratory at NCAR's Computational and Information Systems Laboratory, sponsored by the NSF and other agencies. Work at the Jet Propulsion Laboratory, California Institute of Technology, was carried out under a contract with the National Aeronautics and Space Administration. The Atmospheric Chemistry Experiment (ACE), also known as SciSat, is a Canadian-led mission mainly supported by the Canadian Space Agency. Odin is a Swedish-led satellite project funded jointly by Sweden (SNSB), Canada (CSA), Finland (TEKES), and France (CNES) and is part of European Space Agency's (ESA) third-party mission program. We thank two anonymous reviewers for helpful suggestions that led to improvements in the quality of the present work.Peer reviewe
МОДЕЛЮВАННЯ РЕЖИМІВ РОБОТИ СУДНОВОЇ ЕНЕРГЕТИЧНОЇ УСТАНОВКИ КОМБІНОВАНОГО ПРОПУЛЬСИВНОГО КОМПЛЕКСУ ІЗ СИСТЕМОЮ КЕРУВАННЯ НА ОСНОВІ ЕЛЕКТРОННИХ РЕГУЛЯТОРІВ
Purpose. Designing of diagrams to optimize mathematic model of the ship power plant (SPP) combined propulsion complexes (CPC) for decreasing operational loss and increasing fuel efficiency with simultaneous load limiting on medium revolutions diesel generator (MRDG) by criterion reducing of wear and increasing operation time between repairs. Methodology. After analyzing of ship power plant modes of CPC proposed diagrams to optimize mathematic model of the above mentioned complex. The model based on using of electronic controllers in automatic regulation and control systems for diesel and thruster which allow to actualize more complicated control algorithm with viewpoint of increasing working efficiency of ship power plant at normal and emergency modes. Results. Determined suitability of comparative computer modeling in MatLab Simulink for building of imitation model objects based on it block diagrams and mathematic descriptions. Actualized diagrams to optimize mathematic model of the ship’s power plant (SPP) combined propulsion complexes (CPC) with Azipod system in MatLab Simulink software package Ships_CPC for decreasing operational loss and increasing fuel efficiency with simultaneous load limiting on medium revolutions diesel generator (MRDG) by criterion reducing of wear and increasing operation time between repairs. The function blocks of proposed complex are the main structural units which allow to investigate it normal and emergency modes. Originality. This model represents a set of functional blocks of the components SPP CPC, built on the principle of «input-output». For example, the function boxes outputs of PID-regulators of MRDG depends from set excitation voltage and rotating frequency that in turn depends from power-station load and respond that is a ship moving or dynamically positioning, and come on input (inputs) of thruster rotating frequency PID-regulator models. Practical value. The results of researches planned to use in creation of software package Ships_CPC, in Mat Lab/Simulink was developed under the state budget project «Concepts, technologies and ways of improving ship plants combined propulsion complexes» at the Department of Electromechanics and Electrical Engineering of National University «Odessa Maritime Academy» (State registration number 0114u000340).В результате анализа режимов работы судовой энергетической установки комбинированного пропульсивного комплекса предложены схемы оптимизации математической модели указанного комплекса. Модель основана на применении электронных регуляторов в системах автоматического регулирования и управления дизелем и подруливающим устройством, которые позволяют реализовать более сложные алгоритмы управления с точки зрения повышения эффективности работы судовой энергетической установки при нормальных и аварийных режимах.У результаті аналізу режимів роботи суднової енергетичної установки комбінованого пропульсивного комплексу запропоновані схеми оптимізації математичної моделі зазначеного комплексу. Модель основана на застосуванні електронних регуляторів в системах автоматичного регулювання і управління дизелем і підрулюючим пристроєм, які дозволяють реалізувати більш складні алгоритми управління з точки зору підвищення ефективності роботи суднової енергетичної установки при нормальних і аварійних режимах
Consideration of Reaction Forces of Holonomic Constraints as Generalized Coordinates in Approximate Determination of Lower Frequencies of Elastic Systems
A new method for determination of lower frequencies of mechanical systems consisting of elastic bodies connected to each other is offered. The conditions of connection of bodies are written as holonomic constraints, the reactions of which are considered as generalized coordinates. Therefore the number of degrees of freedom proves to be equal to the number of constraints
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