34 research outputs found
Digital Twin Application in Teaching Students Majoring in Metallurgical Engineering
The article addresses the crucial issues of training engineering personnel with the use of digital twins. In particular, application of digital twins is highly relevant when it comes to training of metallurgical engineering students. At present, teaching of students majoring in metallurgy involving the use of casting aluminum alloys physical models has a number of restrictions such as a high cost of expandable material, safety regulations, the need to provide special access. In this context, the purpose of this article is to identify the advantages and disadvantages of the digital twin of mo dern technology for casting aluminum alloys for application in the educational process. The digital twin created at the Siberian Federal University is a digital analogue of modern industrial complexes used at metallurgical enterprises. The methodological support and a script provided testing of the digital twin on the master’s students studying in the educational program 22.04.02.07 “Theory and technology of foundry production of non-ferrous metals and alloys”, direction of training 22.04.02 Metallurgy. The educational functionality of the model consists in passing the scenarios in the training and examination modes, which enables to test theoretical knowledge, gain skills and consolidate the skills of students. The training mode includes the necessary sequence of actions for passing one of the scenarios. The exam mode monitors user’s actions with saving his history, on the basis of which a report with the final grade is formed. It is planned that as a result of using the digital twin of the semicontinuous casting of aluminum alloys in the educational process, graduates will develop general professional, professional mandatory and professional competencies
Objectives of the Millimetron Space Observatory science program and technical capabilities of its realization
We present the scientific program of the Spectr-M project aimed at the creation and operation of the Millimetron Space Observatory (MSO) planned for launch in the late 2020s. The unique technical capabilities of the observatory will enable broadband observations of astronomical objects from 50 μm to 10 mm wavelengths with a record sensitivity (up to ~ 0.1 μJy) in the single-dish mode and with an unprecedented high angular resolution (~ 0.1 μas) in the ground-space very long baseline interferometer (SVLBI) regime. The program addresses fundamental priority issues of astrophysics and physics in general that can be solved only with the MSO capabilities: 1) the study of physical processes in the early Universe up to redshifts z ~ 2 × 106 through measuring μ-distortions of the cosmic microwave background (CMB) spectrum, and investigation of the structure and evolution of the Universe at redshifts z < 15 by measuring y-distortions of the CMB spectrum; 2) the investigation of the geometry of space-time around supermassive black holes (SMBHs) in the center of our Galaxy and M87 by imaging surrounding shadows, the study of plasma properties in the shadow formation regions, and the search for observational manifestations of wormholes; 3) the study of observational manifestations of the origin of life in the Universe - the search for water and biomarkers in the Galactic interstellar medium. Moreover, the technical capabilities of the MSO can help solve related problems, including the birth of the first galaxies and SMBHs (z ≳ 10), alternative approaches to measuring the Hubble constant, the physics of SMBHs in 'dusty' galactic nuclei, the study of protoplanetary disks and water transport in them, and the study of 'ocean worlds' in the Solar System
The Flavor Asymmetry of the Light Quark Sea from Semi-inclusive Deep-inelastic Scattering
The flavor asymmetry of the light quark sea of the nucleon is determined in
the kinematic range 0.02<x<0.3 and 1 GeV^2<Q^2<10 GeV^2, for the first time
from semi-inclusive deep-inelastic scattering. The quantity
(dbar(x)-ubar(x))/(u(x)-d(x)) is derived from a relationship between the yields
of positive and negative pions from unpolarized hydrogen and deuterium targets.
The flavor asymmetry dbar-ubar is found to be non-zero and x dependent, showing
an excess of dbar over ubar quarks in the proton.Comment: 7 Pages, 2 figures, RevTeX format; slight revision in text, small
change in extraction of dbar-ubar and comparison with a high q2
parameterizatio
Beam-Induced Nuclear Depolarisation in a Gaseous Polarised Hydrogen Target
Spin-polarised atomic hydrogen is used as a gaseous polarised proton target
in high energy and nuclear physics experiments operating with internal beams in
storage rings. When such beams are intense and bunched, this type of target can
be depolarised by a resonant interaction with the transient magnetic field
generated by the beam bunches. This effect has been studied with the HERA
positron beam in the HERMES experiment at DESY. Resonances have been observed
and a simple analytic model has been used to explain their shape and position.
Operating conditions for the experiment have been found where there is no
significant target depolarisation due to this effect.Comment: REVTEX, 6 pages, 5 figure
Measurement of the Spin Asymmetry in the Photoproduction of Pairs of High-pT Hadrons at HERMES
We present a measurement of the longitudinal spin asymmetry A_|| in
photoproduction of pairs of hadrons with high transverse momentum p_T. Data
were accumulated by the HERMES experiment using a 27.5 GeV polarized positron
beam and a polarized hydrogen target internal to the HERA storage ring. For
h+h- pairs with p_T^h_1 > 1.5 GeV/c and p_T^h_2 > 1.0 GeV/c, the measured
asymmetry is A_|| = -0.28 +/- 0.12 (stat.) +/- 0.02 (syst.). This negative
value is in contrast to the positive asymmetries typically measured in deep
inelastic scattering from protons, and is interpreted to arise from a positive
gluon polarization.Comment: 5 pages (latex), 4 figures (eps
Measurement of Longitudinal Spin Transfer to Lambda Hyperons in Deep-Inelastic Lepton Scattering
Spin transfer in deep-inelastic Lambda electroproduction has been studied
with the HERMES detector using the 27.6 GeV polarized positron beam in the HERA
storage ring. For an average fractional energy transfer = 0.45, the
longitudinal spin transfer from the virtual photon to the Lambda has been
extracted. The spin transfer along the Lambda momentum direction is found to be
0.11 +/- 0.17 (stat) +/- 0.03 (sys); similar values are found for other
possible choices for the longitudinal spin direction of the Lambda. This result
is the most precise value obtained to date from deep-inelastic scattering with
charged lepton beams, and is sensitive to polarized up quark fragmentation to
hyperon states. The experimental result is found to be in general agreement
with various models of the Lambda spin content, and is consistent with the
assumption of helicity conservation in the fragmentation process.Comment: 8 pages, 3 figures; new version has an expanded discussion and small
format change
Observation of a Single-Spin Azimuthal Asymmetry in Semi-Inclusive Pion Electro-Production
Single-spin asymmetries for semi-inclusive pion production in deep-inelastic
scattering have been measured for the first time. A significant target-spin
asymmetry of the distribution in the azimuthal angle phi of the pion relative
to the lepton scattering plane was observed for pi+ electro-production on a
longitudinally polarized hydrogen target. The corresponding analyzing power in
the sin(phi) moment of the cross section is 0.022 +/- 0.005 +/- 0.003. This
result can be interpreted as the effect of terms in the cross section involving
chiral-odd spin distribution functions in combination with a time-reversal-odd
fragmentation function that is sensitive to the transverse polarization of the
fragmenting quark.Comment: 5 pages of RevTex, 3 ps figures, 2 table
Observation of a Coherence Length Effect in Exclusive Rho^0 Electroproduction
Exclusive incoherent electroproduction of the rho^0(770) meson from 1H, 2H,
3He, and 14N targets has been studied by the HERMES experiment at squared
four-momentum transfer Q**2>0.4 GeV**2 and positron energy loss nu from 9 to 20
GeV. The ratio of the 14N to 1H cross sections per nucleon, known as the
nuclear transparency, was found to decrease with increasing coherence length of
quark-antiquark fluctuations of the virtual photon. The data provide clear
evidence of the interaction of the quark- antiquark fluctuations with the
nuclear medium.Comment: RevTeX, 5 pages, 3 figure
Determination of the Deep Inelastic Contribution to the Generalised Gerasimov-Drell-Hearn Integral for the Proton and Neutron
The virtual photon absorption cross section differences [sigma_1/2-sigma_3/2]
for the proton and neutron have been determined from measurements of polarised
cross section asymmetries in deep inelastic scattering of 27.5 GeV
longitudinally polarised positrons from polarised 1H and 3He internal gas
targets. The data were collected in the region above the nucleon resonances in
the kinematic range nu < 23.5 GeV and 0.8 GeV**2 < Q**2 < 12 GeV**2. For the
proton the contribution to the generalised Gerasimov-Drell-Hearn integral was
found to be substantial and must be included for an accurate determination of
the full integral. Furthermore the data are consistent with a QCD
next-to-leading order fit based on previous deep inelastic scattering data.
Therefore higher twist effects do not appear significant.Comment: 6 pages, 3 figures, 1 table, revte
Objectives of the Millimetron Space Observatory Science Program and Technical Capabilities of Its Realization
We present the scientific program of the Spectr-M project aimed at the creation and operation of the Millimetron Space Observatory (MSO) planned for launch in the late 2020s. The unique technical capabilities of the observatory will enable broadband observations of astronomical objects from 50 μm to 10 mm wavelengths with a record sensitivity (up to ∼0.1 μJy) in the single-dish mode and with an unprecedented high angular resolution (∼0.1 μas) in the ground-space very long baseline interferometer (SVLBI) regime. The program addresses fundamental priority issues of astrophysics and physics in general that can be solved only with the MSO capabilities: 1) the study of physical processes in the early Universe up to redshifts z ∼ 2 106 through measuring μ-distortions of the cosmic microwave background (CMB) spectrum, and investigation of the structure and evolution of the Universe at redshifts z<15 by measuring y-distortions of the CMB spectrum; 2) the investigation of the geometry of space-time around supermassive black holes (SMBHs) in the center of our Galaxy and M87 by imaging surrounding shadows, the study of plasma properties in the shadow formation regions, and the search for observational manifestations of wormholes; 3) the study of observational manifestations of the origin of life in the Universe - the search for water and biomarkers in the Galactic interstellar medium. Moreover, the technical capabilities of the MSO can help solve related problems, including the birth of the first galaxies and SMBHs (z ⪆ 10), alternative approaches to measuring the Hubble constant, the physics of SMBHs in 'dusty' galactic nuclei, the study of protoplanetary disks and water transport in them, and the study of 'ocean worlds' in the Solar System. © 2021 Uspekhi Fizicheskikh Nauk, Russian Academy of Sciences and IOP Publishing.We appreciate the referees for their critical notes.Thestudy was partially supported by the project New Scientific Groups of LPI, no. 41-2020. AP thanks the RSF for its support (project 19-72-00064). AB is supported by RSF grant 18-12-00351 and by the State Target FEUZ-2020-0038. The work by IZ (Section 4) is supported by RFBR grant 18-02-00660. DV was supported by a grant from the Russian Government and Ministry of Higher Education and Science, 075-15-2020-780 (no. 13.1902.21.0039). The work by VSh (Section 4.4) was supported by a grant from the Russian Government for research by leading scientists under the program Studies of Stars with Exoplanets (agreement 075-15-2019-1875)