bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Visual Survey Group: A Decade of Hunting Exoplanets and Unusual Stellar Events with Space-based Telescopes
Authors: Kristiansen Martti H. K. , Rappaport Saul A. , Vanderburg Andrew M. , Jacobs Thomas L. , Martin Schwengeler Hans , Gagliano Robert , Terentev Ivan A. , LaCourse Daryll M. , Omohundro Mark R. , Schmitt Allan R. , Powell Brian P. , Kostov Veselin B. 
Published: July 2022

Abstract
This article presents the history of the Visual Survey Group (VSG)—a Professional-Amateur (Pro-Am) collaboration within the field of astronomy working on data from several space missions (Kepler, K2 and Transiting Exoplanet Survey Satellite). This paper covers the formation of the VSG, its survey-methods including the most common tools used and its discoveries made over the past decade. So far, the group has visually surveyed nearly 10 million light curves and authored 69 peer-reviewed papers which mainly focus on exoplanets and discoveries involving multistellar systems. The preferred manual search-method carried out by the VSG has revealed its strength by detecting numerous objects which were overlooked or discarded by automated search programs, uncovering some of the most rare stars in our galaxy, and leading to several serendipitous discoveries of unprecedented astrophysical phenomena. The main purpose of the VSG is to assist in the exploration of our local universe, and we therefore advocate continued crowd-sourced examination of time-domain data sets, and invite other research teams to reach out in order to establish collaborating projects.
A first order superfluid-Mott insulator transition for a Bose–Hubbard model in an emergent lattice
Authors: Chen Yu 
Published: July 2022

Abstract
The combination of strong correlation and emergent lattice can be achieved when quantum gases are confined in a superradiant Fabry–Perot cavity. In addition to the discoveries of exotic phases, such as density wave ordered Mott insulator and superfluid, a surprising kink structure is found in the slope of the cavity strength as a function of the pumping strength. In this article, we show that the appearance of such a kink is a manifestation of a liquid–vapour-like transition between two superfluids with different densities. The slopes in the immediate neighborhood of the kink become divergent at the liquid–vapour critical points and display a critical scaling law with a critical exponent 1 in the quantum critical region.
Amplitude and phase modulation of optical feedback in a-cut Nd:YVO4 laser with a birefringent external cavity
Authors: Deng Shiwei , Zhang Zhiyuan , Shen Hua , Han Jianping , Liu Weixin 
Published: July 2022

Abstract
Considering only the self-mixing interference taking place, the modulation effect of optical feedback in a single polarization a-cut Nd:YVO4 laser is presented. The output intensity of the laser with anisotropic gain medium is modulated with a wave plate (WP) in the external cavity. The rotation orientation and phase retardation of the WP regularly determinate the amplitude and phase of laser intensity fringe, because the feedback light component at the same polarization direction as the output laser can interact with the light field in the cavity. The corresponding theoretical model is established and the windowed Fourier transform method is utilized to quantitatively explain this phenomenon. By introducing the amplitude and phase modulation coefficients, comparisons of experimental results with simulation analysis show good consistency.
Mathematical model and PID control of a hydraulic motor using on/off solenoid valve
Authors: Aborobaa A N , Ghamry K A , Saleh A , Mabrouk M H 
Published: July 2022

Abstract
Hydraulic motors have a high power capacity that makes them commonly used in different applications. These applications require precise control of hydraulic motors’ position, velocity, and force. Digital hydraulic valves are commonly used in hydraulic power systems. The high-speed on/off valves (HSVs) are digital valves usually used in flow or pressure control where high dynamic performance is required to improve the control accuracy. This paper aims to present an accurate method of controlling a hydraulic motor using HSV and PID control. A mathematical model of the whole system is presented. This model allows predicting the system response and refining the control gains to reach the desired response. The model parameters are obtained by experimental measurement, or typical values are used. The model is implemented using MATLAB and SIMULINK. Then it is validated experimentally using some tests. The designed control method is implemented on the motor using NI myRIO as a controller, which is coded by LabVIEW software
Nonparametric modeling of magnetorheological damper based on nonlinear black-box technique
Authors: Abdelhamed M , Ata W G , Salem A M 
Published: July 2022

Abstract
Magnetorheological (MR) dampers are considered the most confident actuators for controlling vibratory systems due to their great advantages like high controllable dynamic range, low power consumption, and fail-safe devices. In this paper, a new nonparametric technique is utilised to model the MR-damper dynamics using Non-Linear Autoregressive Models with Exogenous Inputs (NLARX) approach. The proposed model is constructed based on the measured displacement, velocity, and damping forces of the commercial MR damper under various command voltages. The results of the nonparametric model show that such a model can expect the nonlinear dynamics of the MR damper under a wide range of different operating conditions. Furthermore, the proposed model output is compared with a well-known parametric model namely as Modified Bouc-Wen (MBW) model for additional validation. The comparison shows that the generated model can accurately track the measured damping force characteristics, work done by the damper, and the force-velocity hysteresis. It is also shown that the improvement of the damping force of the proposed model is better than the corresponding damping force of the parametric model which clearly shows the robustness of the generated model. The proposed model improves the root mean square (RMS) values of the experimental damping force by about 93.57% compared to an improvement of about 77.36% of the simulated damping force from the MBW model.
Thrust termination of solid rocket motor
Authors: Abdelraouf A M , Mahmoud O K , Al-Sanabawy M A 
Published: July 2022

Abstract
Rocket motors are engines that create the necessary thrust for the rocket motion. There are different types of rocket motors based on the propellant state, such as solid propellant rocket motors, liquid propellant rocket motors, and hybrid propellant rocket motors. One of the biggest disadvantages of solid propellant rocket motors, in comparison to liquid and hybrid propellant rocket motors, is that they are extremely difficult to extinguish, necessitating the use of specific devices. This paper reviews various ways for thrust termination such as fluid injection, rapid increase in throat area, and sudden opening of an additional port at the forward section of the motor, which increases the depressurization rate (dp/dt) required for extinguishing. The rate of depressurization varies depending on propellant components, combustion pressure, and exhaust pressure, and may be investigated using experimental approaches. The change in the critical area for a motor can be predicted by using MATLAB code to ensure the complete extinguishing by decreasing the pressure under the deflagrationlimit with high depressurization rate.
Experimental studies on thermophysical properties of ethylene glycol/water-based MgO nanofluids
Authors: Gamal M , Radwan M S , Elgizawy I G , Shedid M H 
Published: July 2022

Abstract
In the present study, the aim is to experimentally measure the isobaric specific heat, viscosity and thermal conductivity of different magnesium oxide (MgO) nanoparticles concentrations dispersed in ethylene glycol/ water mixture with ratio 50:50 vol% as a base fluid. The experiments were performed on 20 nm particle size of MgO nanoparticles suspended in base fluid with different volume fractions from 0.25 to 1% and temperature range from 40 to 120°C. The data results detected that the specific heat capacity of nanofluids reduces as the nanoparticles volume fraction increases but increases as the temperature rises. For all volume concentrations, the dynamic viscosity declines non-linearly with rising temperature. The increase in viscosity related to the base fluid is slightly recognized at low nanoparticles concentrations, while this change is more sensible at higher volume concentrations. Generally, MgO nanofluids showing higher viscosities than the base fluid used. The thermal conductivity of examined nanofluids increases uniformly with increasing the nanofluid sample temperature and nanoparticles volume concentration.
Comparative analysis of optimization strategies by software complex “Metaheuristic nature-inspired methods of global optimization”
Authors: Panteleev A V , Belyakov I A , Kolessa A A 
Published: July 2022

Abstract
This article discusses the comparative efficiency analysis results of algorithms for finding a global extrema for multivariable functions with parallelepiped constraints. Three metaheuristic nature-inspired optimization algorithms such as Grey Wolf Optimizer (GWO), Whale Optimization Algorithm (WOA) and Perch School Search (PSS) are presented. For algorithms comparative analysis the software complex was created, which allows visualizing a process of obtaining the approximate solution of standard generally accepted benchmark problems. The different examples of optimization algorithms results are given. Benchmark functions structure provides fairly estimating of compared optimization methods. The purpose of the paper is collecting and subsequent analysis of statistical results of algorithms accuracy and convergence pattern. Statistical data analysis makes it possible to choose the most suitable optimization method and to formulate valid recommendations to pick parameters for the most efficient solution of arbitrary objective function optimization problem.
Computer simulation of the physical neutralization of drones in a Smart City
Authors: Tovarnov M S , Bykov N V , Vlasova N S , Fedulov V A , Pozharsky A A 
Published: July 2022

Abstract
We present a simple computer simulation model for the interaction of automatic guns with unarmed drones. Each drone is represented as a rigid body that consists of several simple bodies such as parallelepipeds, ellipsoids, etc. The simplified spatial trajectory of the drone is constructed using third-order Bezier curves. A relatively large group of unconnected drones may be simulated in a computationally fast way using this method. Automatic guns are agents that are shooting at drones with a single of burst fire relative to the ideal aiming point. We performed a simulation of the flight of several drones against several automatic guns for different conditions. As a result of this simulation, the spatial distribution of the drone hit probabilities, the special distribution of the fraction of defeated drones depending on the number of guns, and the influence of urban obstacles on the fraction of drones defeated are presented.
The use of modern computer technologies in the study of the Geometric Modeling course
Authors: Zakharov A A , Zakharova Yu V 
Published: July 2022

Abstract
The paper describes the educational discipline “Geometric modeling”, which is suitable for students of applied mathematics. The course covers spline representations and transfinite interpolation methods for modeling the shape of geometric objects, the methods for performing Boolean operations between objects and methods for visualizing the objects. Screenshots of some graphic windows of the developed visualization programs for supporting the implementation of individual assignments in the course are shown. The programs have web interfaces that use the WebGL graphics API in a browser, independent of an operating system, and are also available for smartphones and tablets. They provide graphical output for curves and surfaces in three-dimensional space, user interfaces for entering the initial data and interaction with geometric objects. Students only need to write their own calculation code for the programs in the JavaScript programming language. The interactive tools enable students to get practical skills in working with splines and visually analyze the impact of the input data on the final geometry. The individual assignments and programs are specially focused to stimulate students’ interests. The paper is addressed to teachers of the geometric modeling for mathematicians and computer scientists. It seems to be interesting to those who develop software interfaces for geometric modeling algorithms.
Fractal feedback control for Elastic computing based on the Container–Component model
Authors: Semenov A S 
Published: July 2022

Abstract
One of the most significant characteristics of cloud computing is elasticity, which refers to the autoscaling control of resources based on the demands of the application or service. The problem of setting parameters of elastic autoscaling is not trivial and its solution depends on the control model. The Container-Component model that exploits the properties of fractals is investigated for this purpose. The fractal dimension is proposed to characterize the auto-scalability of distributed computing, independent of the implementation. The control of the fractal complexity by means of fractal feedback is considered.
Utilization of parallel computing for mathematical modeling of high-enthalpy flows
Authors: Gribinenko D V , Molchanov A M , Siluyanova M V , Yanyshev D S 
Published: July 2022

Abstract
The complexity of problems in gas dynamics is increasing from year to year, which makes sequential computational codes more and more inadequate and brings the importance of creating their parallel implementations. The problem of building the parallel implementations is not simple, especially in case of parallelization of the existing sequential codes. In this paper we present a method of simulation of high-enthalpy flows and describe the peculiarities of its parallel implementation utilizing PETSc library, which gives a wide variety of tools to simplify creation of parallel codes. The results for calculation of OREX reentry module as well as analysis of scalability of the parallel code implementation are given.
Impact of electronic excitation on the state-to-state vibrational-chemical CO kinetics
Authors: Yu Melnik M , Kustova E V 
Published: July 2022

Abstract
Dissociation of carbon monoxide in shock heated flows is studied with emphasis to the phenomenon of dissociation induction. Different kinetic schemes are implemented, both neglecting and including electronic excitation; various vibrational and electronic state-resolved models of dissociation rate coefficients are assessed. Vibrational-electronic relaxation coupled to dissociation behind the shock front is simulated in the frame of the state-to-state approach for several test cases with varying initial pressure, temperature, mixture composition and shock velocity. It is found that dissociation delay may appear regardless taking into account electronic excitation; the incubation time is mainly governed by mixture composition and initial pressure. Electronic excitation noticeably influences the overall dissociation rate. Recommendations for using specific dissociation models are given for different test cases.
Numerical study of the separation of a turbulent boundary in rocket engine nozzles with an optimized supersonic part
Authors: Shustov S A , Ivanov I E , Kryukov I A 
Published: July 2022

Abstract
At present, propulsion systems are being developed for flights of aerospace vehicles both in the Earth’s atmosphere and beyond. At the stage of the propulsion system design, it is necessary to be able to reliably determine the energy and thrust characteristics of rocket engines in regimes with flow separation in the nozzle for a wide range of nozzle pressure ratio (NPR) (1 ≤ m ≤ 30, m = ph
/pa
, p—pressure, indices h and a refer, respectively, to the parameters of the external environment and at the nozzle exit) characterizing the flow in nozzles and jets. In this case, the nozzle, as a rule, has a thrust optimized contour (TOC) supersonic part. In this regard, we present some results of a numerical study of flows with separation of the turbulent boundary layer in the TOC nozzles of main rocket engines in the above range of the NPR based on the Reynolds Averaged Navier–Stokes (RANS) system of equations.
Influence of magnetic field on the amplitude of flutter type oscillations of dielectric plate
Authors: Baghdasaryan G Y , Panteleev A V , Mikilyan M A 
Published: July 2022

Abstract
Stability problem of an isotropic dielectric plate streamlined by a supersonic gas flow is considered, when the plate is immersed in a longitudinal magnetic field. On the basis of the piston theory, the theory of magnetoelasticity and Maxwell equations, the appropriate formula for aerodynamic pressure is obtained, which can be used as an extension of piston formula. Formula is obtained to calculate the critical speed of flowing stream. On the basis of this formula the influence of magnetic field on the critical speed is studied. The system of non-linear differential equations is obtained, Galerkin method is used and the piston theory aerodynamic model for supersonic flow are employed to obtain the results.
Marine heatwaves in global sea surface temperature records since 1850
Authors: von Kietzell Arno , Schurer Andrew , Hegerl Gabriele C 
Published: July 2022

Abstract
The adverse impacts of marine heatwaves (MHWs) on marine ecosystems and human activities are well-documented, yet observational studies tend to largely rely on recent records. Long-term records of MHWs can put the recent increase in frequency and intensity of MHWs in the context of past variability. We used long-term monthly sea surface temperature (SST) data and night marine air temperatures to characterise past MHW activity. A persistent increase in the global extent of MHWs is demonstrated, beginning around 1970. The average annual MHW extent post-2010 is estimated to be increased at least four fold compared to that pre-1970. A strong correlation between spatial variance of recorded average monthly SSTs and the average inverse number of monthly observations implies both frequency and amplitude of MHWs is overestimated when the number of monthly observations is low. Nevertheless, many identified early MHWs appear genuine, such as a multi-month event in the North Atlantic in 1851–1852. MHWs are also affected by poorer sampling during the world wars. The most extensive MHW years globally coincide with El Niño years, and MHW extent in the North Atlantic is correlated with the Atlantic Multidecadal Oscillation.
Detecting inhomogeneous chiral condensation from the bosonic two-point function in the (1 + 1)-dimensional Gross–Neveu model in the mean-field approximation*
Authors: Koenigstein Adrian , Pannullo Laurin , Rechenberger Stefan , Steil Martin J , Winstel Marc 
Published: July 2022

Abstract
The phase diagram of the (1 + 1)-dimensional Gross–Neveu model is reanalyzed for (non-)zero chemical potential and (non-)zero temperature within the mean-field approximation. By investigating the momentum dependence of the bosonic two-point function, the well-known second-order phase transition from the

Z

2

symmetric phase to the so-called inhomogeneous phase is detected. In the latter phase the chiral condensate is periodically varying in space and translational invariance is broken. This work is a proof of concept study that confirms that it is possible to correctly localize second-order phase transition lines between phases without condensation and phases of spatially inhomogeneous condensation via a stability analysis of the homogeneous phase. To complement other works relying on this technique, the stability analysis is explained in detail and its limitations and successes are discussed in context of the Gross–Neveu model. Additionally, we present explicit results for the bosonic wave-function renormalization in the mean-field approximation, which is extracted analytically from the bosonic two-point function. We find regions—a so-called moat regime—where the wave function renormalization is negative accompanying the inhomogeneous phase as expected.
Magnetic ring chains with vertex coupling of a preferred orientation
Authors: Baradaran Marzieh , Exner Pavel , Lipovský Jiří 
Published: July 2022

Abstract
We discuss spectral properties of a periodic quantum graph consisting of an array of rings coupled either tightly or loosely through connecting links, assuming that the vertex coupling is manifestly non-invariant with respect to the time reversal and a homogeneous magnetic field perpendicular to the graph plane is present. It is shown that the vertex parity determines the spectral behavior at high energies and the Band–Berkolaiko universality holds whenever the edges are incommensurate. The magnetic field influences the probability that an energy belongs to the spectrum in the tight-chain case, and also it can turn some spectral bands into infinitely degenerate eigenvalues.
Mining and environmental problems of Dalnegorsk, Primorye territory, and ways to solve them
Authors: Filatova M Yu , Krupskaya L T , Kocharyan Yu G , Leonenko A V , Romashkina E A 
Published: July 2022

Abstract
Intensive development of deposits in the Primorsky Territory has led to the accumulation of a large amount of waste from the processing of mineral raw materials, which has a negative impact on the environment. The environmental situation is aggravated by the fact that tailings, where processing waste is stored, located near settlements (for example, Dalnegorsk). The protection of the ecosphere is an urgent geoecological problem. Therefore, the purpose of the study was to study the mining and environmental problems of ensuring the environmental safety of the technogenic system. The methodological basis of the study was the teaching of Academician V.I. Vernadsky about the biosphere and noosphere and the main provisions of B.P. Kolesnikov and A.V. Motorin, set out in the program and methodology for the study of technogenic ecosystems. The scientific novelty of the study lies in the complex geoecological assessment of environmental objects using mathematical methods. The patterns of migration of heavy metal compounds and arsenic from tailings to the components of the ecosphere are revealed. Methods for reducing the negative impact of mountain systems on the environment are substantiated using the capabilities of biological systems, the novelty of which is confirmed by patents of the Russian Federation.
Benzo(a)pyrene in the atmosphere and its carcinogenic risks to the health of the population of Irkutsk region cities
Authors: Belykh L I , Maksimova M A 
Published: July 2022

Abstract
We studied increase in cancer incidence in the population and the dynamics of the carcinogenic benzo(a)pyrene content in the atmospheric air of cities in the Irkutsk Region. Sources of air pollution boilers and household furnaces, aluminum production, motor vehicles, forest fires were considered. Individual and population carcinogenic risks of benzo(a)pyrene for the health of the population in industrial, agricultural and South Baikal cities were assessed. We also could establish the tendency of increasing risks and the dependence of the incidence of malignant neoplasms in the population on the content of benzo(a)pyrene in the atmosphere. The conclusion was made about the need to assess pollution sources, about the development of a monitoring system for benzo(a)pyrene and its analogs - polycyclic aromatic hydrocarbons - in the environment.