bluuebunny/crossref_metadata_2025_split huggingface dataset:
New analytical solutions for the inextensible Heisenberg ferromagnetic flow and solitonic magnetic flux surfaces in the binormal direction
Authors: Körpınar Talat , Demirkol Rıdvan Cem , Körpınar Zeliha 
Published: May 2021

Abstract
Maxwellian electromagnetism describes the wave features of the light and related subjects. Its original formulation was established 150 years ago. One of the four Maxwell’s equations is Gauss’s law, which states significant facts regarding magnetic flux through surfaces. It was also observed that optical media provides surface electromagnetism around 60 years ago. This observation leads to improve new techniques on nano-photonics, metamaterials, and plasmonics. The goal of this manuscript is to suggest novel accurate and local conditions for defining magnetic flux surfaces for the inextensible Heisenberg ferromagnetic flow in the binormal direction. The theoretical accuracy of the methodology is verified through the evolution of magnetic vector fields and the anti-symmetric Lorentz force field operator. On the other hand, the numerical accuracy and efficiency is developed in detail by considering the conformable fractional derivative method when these fields are transformed under the traveling wave hypothesis.
Gravitational-wave detector networks: standard sirens on cosmology and modified gravity theory
Authors: Yang Tao 
Published: May 2021

Abstract
We construct the catalogues of standard sirens (StS) based on the future gravitational wave (GW) detector networks, i.e., the second-generation ground-based advanced LIGO+advanced Virgo+KAGRA+LIGO-India (HLVKI), the third-generation ground-based Einstein Telescope+two Cosmic Explorer (ET+2CE), and the space-based LISA+Taiji. From the corresponding electromagnetic (EM) counterpart detectors for each networks, we sample the joint GW+EM detections from the probability to construct the Hubble diagram of standard sirens for 10 years detections of HLVKI, 5 years detections of ET+2CE, and 5 years of detections of LISA+Taiji, which we estimate would be available and released in the 2030s. Thus we construct a combined Hubble diagram from these ground and spaced-based detector networks to explore the expansion history of our Universe from redshift 0 to 7. We give a conservative and realistic estimation of the catalogue and Hubble diagram of GW standard sirens and their potential on studying cosmology and modified gravity theory in the 2030s. We adopt two strategies for the forecasts. One is the traditional model-fitting Markov-Chain Monte-Carlo method (MCMC). The results show that the combined StS alone can constrain the Hubble constant at the precision level of 0.34%, 1.76 times more tightly than the current most precise measurement from Planck+BAO+Pantheon. The joint StS with current EM experiments will improve the constraints of cosmological parameters significantly. The modified gravity theory can be constrained with 0.46% error from the GW propagation. In the second strategy, we use the machine-learning nonparametric reconstruction techniques, i.e., the Gaussian process (GP) with the Artificial Neural Networks (ANN) as a comparison. GP reconstructions can give comparable results with MCMC. We anticipate more works and research on these topics.
Effective theory of inflationary magnetogenesis and constraints on reheating
Authors: Maity Debaprasad , Pal Sourav , Paul Tanmoy 
Published: May 2021

Abstract
Effective theory framework based on symmetry has recently
gained widespread interest in the field of cosmology. In this
paper, we apply the same idea on the genesis of the primordial
magnetic field and its evolution throughout the cosmological
universe. Given the broken time-diffeomorphism symmetry by the
cosmological background, we considered the most general Lagrangian
of electromagnetic and metric fluctuation up to second order, which
naturally breaks conformal symmetry in the electromagnetic (EM)
sector. We also include parity violation in the electromagnetic
sector with the motivation that has potential observational
significance. In such a set-up, we explore the evolution of EM,
scalar, and tensor perturbations considering different observational
constraints. In our analysis we emphasize the role played by the
intermediate reheating phase which has got limited interest in all
the previous studies. Assuming the vanishing electrical conductivity
during the entire period of reheating, the well-known Faraday
electromagnetic induction has been shown to play a crucial role in
enhancing the strength of the present-day magnetic field. We show
how such physical effects combined with the PLANCK and the large
scale magnetic field observation makes a large class of models
viable and severely restricts the reheating equation of state
parameter within a very narrow range of 0.01 < ωeff < 0.27, which is nearly independent of reheating scenarios we
have considered.
Searching for axion-like particle decay in the near-infrared background: an updated analysis
Authors: Caputo Andrea , Vittino Andrea , Fornengo Nicolao , Regis Marco , Taoso Marco 
Published: May 2021

Abstract
The extragalactic background light is comprised of the cumulative radiation from all galaxies across the history of the universe. The angular power spectrum of the anisotropies of such a background at near-infrared (IR) frequencies lacks of a complete understanding and shows a robust excess which cannot be easily explained with known sources. Dark matter in the form of axion-like particles (ALPs) with a mass around the electronvolt will decay into two photons with wavelengths in the near-IR band, possibly contributing to the background intensity. We compute the near-IR background angular power spectrum including emissions from galaxies, as well as the contributions from the intra-halo light and ALP decay, and compare it to measurements from the Hubble Space Telescope and Spitzer. We find that the preferred values for the ALP mass and ALP-photon coupling to explain the excess are in tension with star cooling data and observations of dwarf spheroidal galaxies.
Reconstruction of reionization history through dispersion measurements of fast radio bursts
Authors: Dai Ji-Ping , Xia Jun-Qing 
Published: May 2021

Abstract
In this paper, we study the evolution of the ionization
fraction x
e(z) during the epoch of reionization by using the
dispersion measurements (DMs) of fast radio bursts (FRBs). Different
from the previous studies, here we turn to consider the large-scale
clustering information of observed DMs of FRB catalog, which only
needs the rough redshift distribution, instead of the exact redshift
information of each FRB. Firstly, we consider the instantaneous
“tanh” model for x
e(z) and find that including the
auto-correlation information of the mock catalog, about 104 FRBs
with the intrinsic DM scatter of 100 pc/cm3 spanning 20% of
all sky, could significantly improve the constraint on the width
Δz of the model, when comparing with that from the CMB data
alone. The evolution shape of the ionization fraction will be
tightly narrowed, namely the duration of the epoch of reionization
has been shrunk, z
dur < 2.24 (95% C.L.). Furthermore, we
also use another redshift-asymmetric reionization model and obtain
that the FRB mock catalog could measure the ionization fraction at
z = 6 precisely with the 1σ error Δ x
e (z = 6) = 0.012,
which means that the large-scale clustering information of observed
DMs of FRB catalog is very sensitive to the ionization fraction of
the end of reionization epoch. We conclude that the observation of
high-redshift FRBs could be a complementary probe to study the
reionization history in the future.
The First Photometric Investigation and Spectroscopic Analysis of Two Contact Binaries: ASAS J124343+1531.7 and LINEAR 2323566
Authors: Xia Qiqi , Michel Raul , Li Kai , Higuera Jesus 
Published: May 2021

Abstract
The multi-color passband CCD light curves of ASAS J124343+1531.7 and LINEAR 2323566 were first obtained by the 0.84 m Ritchey–Chrétien telescope with follow up observations by the WIYN 0.90 m Cassegrain telescope. The data from the Transiting Exoplanet Survey Satellite of ASAS J124343+1531.7 was also applied for subsequent analysis. By analyzing the data through the W-D program, their mass ratios and fill-out factors were determined as 3.758, 1.438 and 31.8%, 14.9%, respectively. ASAS J124343+1531.7 is a W-subtype median contact binary, while LINEAR 2323566 is a W-subtype shallow contact binary, and the asymmetric light curves prove that they both have the O’Connell effect, which is generally explained by magnetic activity. The equivalent widths of H
α
lines were calculated, which show they certainly have magnetic activity. Moreover, LINEAR 2323566 has a stronger magnetic activity. The analysis of orbital period changes shows that ASAS J124343+1531.7 has a trend of secular period increase, which is generally explained by the mass transfer from the less massive to the more massive star. According to the estimated absolute parameters, their evolutionary states are discussed. The two components of ASAS J124343+1531.7 are both main sequence stars. While for LINEAR 2323566, the more massive star is a main sequence star, the less massive star has evolved out of main sequence and is over-luminous and over-sized.
Selection of optimal parameters of technological modes for the synthesis of polymer composite materials based on verified mathematical models
Authors: Markov A V , Oreshina O A 
Published: May 2021

Abstract
In the modern realities of creating structural elements for various purposes, polymer composite materials are widely used. These materials are used in almost all industries, from aerospace, shipbuilding, automotive, and ending with consumer goods. The article shows the need to develop mathematical models that reflect the relationship between mechanical properties and parameters of technological modes for the synthesis of polymer composite materials, to select the optimal parameters of the technological mode of their synthesis. The article discusses the optimization of a group of mechanical properties described by mathematical models built on the basis of a full factorial experiment, in order to obtain the optimal values of the parameters of the technological modes of synthesis of a polymer composite material based on heat-resistant low-molecular-weight synthetic rubber with the addition of ferric iron oxide as a filler. The research method is optimization by the method of successive concessions. Computer experiments have been carried out to optimize the parameters of technological modes for the synthesis of materials. The performed calculations were checked with experimental data, the adequacy of the obtained models was checked.
Methods for measuring the reflection coefficient of radio waves
Authors: Samoylov A G , Samoylov S A 
Published: May 2021

Abstract
Methods for measuring the reflection coefficient of non-ionized electromagnetic radiation from sheet materials are considered. Horn antennas with square apertures were used for measurements. The maximum dimensions of the irradiation spot are determined depending on the distance to the irradiating horn antenna for different frequency ranges. Two methods of measuring the reflection coefficient of radio waves from sheet materials are described. The first method is based on the use of two antennas for irradiating the material and for receiving the reflected signal. The second method is based on the use of a measuring line. In this case, one antenna is used. A measuring installation was made.
Method of manufacturing reinforced concrete floor slabs using non-removable void formers
Authors: Pushkarev B A , Burenina N B 
Published: May 2021

Abstract
The article provides a critical analysis of the work on the manufacture of monolithic reinforced concrete, relying on the contour, hollow floor slabs using box-shaped, spherical and tubular hollow-formers. The paper proposes a method of manufacturing monolithic reinforced concrete hollow floor slabs based on the contour using circular tubular polyethylene cardboard holders of rectangular or square shape in plan. The subject of the research is a method of continuous production of reinforced concrete floor slabs with round voids based on the contour using non-removable void formers, their technical and economic efficiency of solutions to reduce the weight of monolithic floor slabs by reducing the resources for their production. The technical and economic feasibility of manufacturing monolithic reinforced concrete floor slabs based on the contour with the use of non-retrievable void formers from round pipes of square and rectangular shape in plan has been substantiated. Materials for the manufacture of void former are proposed. The technical result has been determined - the maximum weight reduction of the proposed hollow core slabs compared to solid slabs.
Generalized functions in non-linear thermal conductivity problem for two-layer structure with heat source
Authors: Mikheeva G V 
Published: May 2021

Abstract
Based on the generalized functions theory an exact analytical solution to the stationary non-linear problem of thermal conductivity for two-layer plate with heat sources for the asymmetrical Newton’s limiting conditions. Dependence of thermal conductivity factors of each layer on the temperature was assumed to be linear. The problem for a two-layer structure, using the Heaviside asymmetric unit function, is normalized to a single-layer one with piecewise homogeneous (discontinuous) properties of the medium. The advantage of this method for obtaining analytical solutions is that there is no need to directly fulfill the conjugation conditions at the layers’ contact points, since, thanks to the use of the Heaviside function, they are included in the generalized differential equation of the boundary value problem and are fulfilled in the process of obtaining its solution. A specific example of calculating the temperature state of a two-layer plate is provided.
Testing of thin-walled cylindrical shells made of steel 45 in solving the problem of stability
Authors: Cheremnykh S V 
Published: May 2021

Abstract
The theory of shell stability beyond the elastic limit is considered when studying the issue of testing, diagnostics and quality control of materials made of steel shells of round cylindrical cross-section. Since, depending on the history of the loading process of an elastic-plastic system, its final deformation corresponding to the same external load is different, by studying the inelastic stability problems should proceed from the analysis of simple combined loading processes that lead to different critical deformations. Not only the question of the loading history, which leads to the minimum value of critical loads, but also the question of choosing and implementing such a loading history of a given system, which gives it the maximum value of the stability limit and the load-bearing capacity of the material, is solved. Innovative methods are proposed for solving the problem of shell stability in tests of complex loading of steel cylindrical shells by internal pressure, compression and torsion in the direction of structural mechanics and mechanics of deformable solids, implemented on an experimental complex. The obtained results allow us to determine the loss of stability of the material beyond the elastic limit with a sufficient degree of accuracy for a given cross-section and the loading trajectory of a cylindrical thin-walled shell made of steel 45, while the correctness of the obtained results is justified experimentally.
Investigation of the mechanisms of the electromagnetic wave effect on the diffusion flame torch
Authors: Stolyarov D V , Koroleva T I , Shaposhnik D S , Ivachev M A , Mikhailov K A 
Published: May 2021

AbstractNew socio-economic conditions for the development of Russia dictate new requirements for the protection of buildings, equipment and personnel of various facilities from fires and their consequences. In complex fire extinguishing systems, the timeliness of fire detection and the effectiveness of extinguishing is the key to preserving material values and human lives. An urgent task is not only the improvement of existing fire extinguishing systems, but also the development of new systems, the basis of which is based on previously unused approaches. These approaches are based both on the previously known physical and chemical methods of extinguishing fires, and on the methods being investigated and studied at present. One of the promising methods of extinguishing fires is the technology of extinguishing fires using the effect of an electromagnetic field on the diffusion flame. The study of this method involves the analysis of physical processes that are electromagnetic in nature of interaction occurring in the system “diffusion flame torch - electromagnetic wave”. In this work, a quantitative analysis of the parameters affecting the possible mechanisms of interaction of the elements of this system is carried out. A mathematical model of the considered physical processes is presented.
Determination of the true density of chaga by gas picnometry in atmospheric air
Authors: Gainullin Renat H , Safina A V , Gainullin Rishat H , Mukhametzyanov S R 
Published: May 2021

Abstract
The considerable interest in the study of chaga (Inonotus obliquus) as an extraction material is due to the unique chemical composition and a wide range of biologically active substances used in various industries. An important parameter reflecting the content of chaga substances in the volume is the true density or the cell wall density not given in the literature. The porous structure of the fungus and the irregular geometric shape of chaga determined the choice of gas pycnometry as a method to measure the true volume and the subsequent determination of chaga cell walls density. After critical analysis, an alternative, theoretically substantiated method for determining the true volume of a porous body in atmospheric air was proposed. The experimental data results were processed to determine the true density of chaga cell walls, which ranges from 1.411g/cm 3 to 1.588g/cm3. The maximum density was in the central part of the fungus. To the periphery of the fungus, there is a decrease in the cell wall density and the lowest density is at the point where the birch fungus adjoins the tree trunk.
Improvement of antifriction properties of tribotechnical cermets by treatment in selenium vapor
Authors: Roshchin M N , Alisin V V 
Published: May 2021

Abstract
The issues of the high-temperature tribological tests of cermets during friction against steel 40X13 in the temperature range from + 600°C to +700°C in atmospheric conditions are studied in the article. The choice of temperature and test atmosphere is due to the prospects of creating friction units for operation without lubrication in extreme operation conditions. Studies have shown that when processing cermet in selenium vapor, the friction coefficient in the temperature range of 600 … 700°C is approximately 8-15% lower at a load of 1.0 MPa than the friction coefficient of untreated samples. It was found that the iron chalcogenide at a temperature of 500°C and above releases Se vapors, which are adsorbed at the tribological contact and create a lubricating layer.
Generation of test method boundaries for refrigeration technology
Authors: Sokolov Ya A , Kovalenko A N , Kolesnikova P V , Korchikov D A , Burleva S A , Boyko D A , Sokolova A A 
Published: May 2021

Abstract
When manufacturing refrigeration appliances, it makes sense to minimize the number of defective products. This can be achieved in several ways. Since the causes of marriage are great, only those that are determined by a person and are not unambiguous should be considered. One of the possible reasons for its decrease is the accurate determination of the numerical values of the parameters of a suitable refrigerator. A deviation from the values obtained in this way will form a suitability range for each temperature. The task is facilitated by the presence of two numerical parameters for suitability: temperature and power. Consequently, if the power is at the level of the working standard refrigerator, and the temperature gained over a certain time is higher than it should be, then the refrigerator can be unambiguously recognized as defective. This article discusses the possibility of an automated calculation of the boundaries of the parameters of the acceptance test methods (ATM). They are carried out before the release of the finished product to the consumer. The calculation is based on real production statistics. The test data forms parameterized point clouds for power and temperature. Classifying points in the cloud will make the boundary calculations more accurate. This will lead to a decrease in the human factor when deciding on suitability. Consequently, the accuracy of determining the defective product will increase.
On improving the efficiency of flooding to increase oil recovery during oil fields development
Authors: Gilyazov A A , Salimov A O , Vadulina N V 
Published: May 2021

Abstract
The article provides an overview of existing hydrodynamic methods of increasing oil recovery, in particular, methods of flooding and oil and gas impact on the formation. Advantages and disadvantages of currently applied methods of water-gas impact on the formation in order to increase oil recovery are considered. The authors conclude that the most effective technology is the technology of joint injection of water and gas into oil-bearing formations to increase their oil recovery when acting on an injection well in non-uniform formations. One method of restoring injection capacity of the injection well and controlling filtration-capacitance characteristics of the bottomhole zone of the well is ultrasonic action. Based on a review of the methods, the most effective technologies for increasing oil recovery of the formation were selected and an acoustic emitter was developed. The radiator developed by the authors is characterized by simplicity of design and use. Dynamics of changes in injectivity indices of injection wells before and after application of acoustic emitter developed by authors is analyzed. Studies have shown an increase in injection well capacity and the efficiency of application of this device due to the fact that a homogeneous water-gas mixture is created directly in the bottomhole zone of the injection well.
Flexural strength of fiber reinforced concrete structures
Authors: Nikolenko S D , Sazonova S A , Asminin V F , Zyazina T V , Mozgovoj N V 
Published: May 2021

Abstract
The paper presents an analysis of dispersed reinforcement methods. Metal fibres have been used when conducting the experiment. It has been shown that the reinforcement of concrete with metal fibers can significantly increase crack resistance for structures made of fiber-reinforced concrete in comparison with similar reinforced concrete structures.It should be noted that blocking crack development and blocking the possibility of the main cracks formation is achieved in structures made of fiber-reinforced concrete due to a more uniform distribution of forces arising in concrete. The results of an experiment on the reaction of beams with dispersed reinforcement to a bending load have been presented. The calculation of stretched and bending element with dispersed and combined reinforcement has been performed. The calculation showed that the use of combined reinforcement in structures can increase their overall bearing capacity. The comparison of the calculation and experiment results has shown a showed good convergence.