bluuebunny/crossref_metadata_2025_split huggingface dataset:
Visualization of hydrodynamic and physico-chemical processes in rotating and vibrating containers
Authors: Kozlov N V , Mosheva E A , Shmyrov A V 
Published: December 2021

Abstract
Variable inertial fields are an efficient way to control the behaviour of hydrodynamic systems. Forces of inertia can be used, for example, to stabilize or destabilize systems with an interface or density gradient, to mix multiphase or non-isothermal fluids. The implementation of this approach means that liquids fill the periodically moving containers. In this paper, the situations are considered when the containers perform either rotation or translational vibrations. Methods for measuring the density and velocity fields of convective flows in reacting hydrodynamic systems are described. Interferometry is used to visualize the density distribution. Particle image velocimetry (PIV) is used to study the structure and velocity of the flows. Optical instruments are installed stationary in the laboratory system. For video recording, a camera shutter is synchronized with the motion of a container, and thus the images are captured in a fixed phase of oscillations or rotation. Constructions of the containers make it possible to illuminate the working volume through transparent walls at different angles or in different planes. They also provide a compensation for the centrifugal pressure and allow interference cells to be used in overload conditions. The successful application of the methods in experimental studies of chemo-hydrodynamic processes is demonstrated.
Reconstruction of the flow structure in a matrix channel based on two-component LDA data
Authors: Philippov M V , Zolotukhin A V , Chokhar I A , Terekhov V V , Terekhov V I , Baranov I N 
Published: December 2021

Abstract
The work is aimed at creating a technique for reconstructing the three-dimensional structure of turbulent flows using data of a two-component laser-Doppler anemometer at the example of a flow in flat coplanar channels. Data of paired measurements by a two-component LDA at two different angles relative to the measurement point are used to obtain information about the three-dimensional structure of the flow. Further, all three components of the velocity vector were calculated using transformations. The developed method is used to measure the velocity field in a coplanar channel.
Propagation of laser beams through curved interfaces of transparent media
Authors: Pavlov I N , Platonova I V , Raskovskaya I L , Yanina G M 
Published: December 2021

Abstract
Mathematical models of propagation of Gaussian, collimated and structured laser beams in transparent optically homogeneous media in the presence of curved interfaces are presented. Experimental techniques which are used for reconstruction of the interfaces profiles are described.
Flow visualization around cylinder under surface discharge action in the still atmosphere
Authors: Ivchenko A V 
Published: December 2021

Abstract
The paper presents the universal gas-discharge system for surface discharge generation on a cylinder body providing PIV experiments and shadow studies. The system enables the flow visualization around cylinder, discharge power consumption measurements and of temperature fields on the cylindrical surface recording. Under surface discharge action on cylindrical surface in the quiescent air, the flow accompanied by the formation of a near-wall vortex structure and a set of the radially-oriented jets is visualized. The observed jets leave the thermal boundary layer and are able to influence to the gas areas located far away. The presented results indicate the effectiveness of the surface discharges use to control gas-dynamic, thermo-physical and mass transfer processes in the vicinity of streamlined bodies such as cylinders.
Investigation of the influence of nonbreaking waves on the turbulence using PIV methods within laboratory modelling of the upper layer ocean dynamics
Authors: Sergeev D A , Kandaurov A A , Troitskaya Yu I 
Published: December 2021

AbstractThe influence of nonbreaking waves on the mixing processes in the upper layer of the ocean during wind-wave interaction was investigated under the conditions of laboratory modeling at the Thermostratified Wind Wave Tank (TSWiWaT) of IAP RAS. Experiments of three types were performed. In the first experiment, shear flow in water was induced using a weak wind to avoid the excitation of surface waves. In the second experiment, in the absence of wind, only a long smooth surface wave was generated using an underwater paddle wavemaker. The third type of experiment combined the conditions of the previous two, i.e. at the same time the wave generator was working and the wind was blowing. In all experiments, the underwater flow characteristics were measured using the PIV method. Vertical profiles of the mean velocity and fluctuations for two components were obtained. It was shown that the presence of waves leads to an increase in the average drift current, as well as, more importantly, on the level of fluctuations over the entire depth of the recorded profile by more than 3 times. This was observed for horizontal and vertical turbulent velocity components both.
Application of convolutional neural networks in optical text recognition to junk data filtering
Authors: Razumov T E , Churikov D V , Kravchenko O V 
Published: December 2021

Abstract
In this paper, the problem of constructing a model for detecting and filtering unwanted spam messages is solved. A fully connected convolutional neural network (FCNN) was chosen as the model of the classifier of unwanted emails in email. It allows you to divide emails into two categories: spam and not spam. The main result of the research is a software application in the C++ language, which has a micro-service architecture and solves the problem of image classification. The app can handle more than 106 requests per minute in real-time.
Neural network classifier for hyperspectral images of skin pathologies
Authors: Vinokurov V , Khristoforova Yu , Myakinin O , Bratchenko I , Moryatov A , Machikhin A , Zakharov V 
Published: December 2021

Abstract
This paper describes the use and results of a neural network classifier trained on a set of hyperspectral images of benign and malignant neoplasms. The analysis is carried out on 2D images extruded from hyperspectral data. The ranges of wavelengths at which the research is carried out is represented by the intervals 530–570 nm and 600–606 nm, which is caused by the assumption that the analysis of the entire spectral range is redundant and the prospect of saving resources. Melanoma, basal cell carcinoma (BCC), nevus and papilloma are accepted as primary classes, as the most dangerous, most common and non-malignant types of neoplasms, respectively. The neural network classifier is based on a three-block VGG network. With a training set included 1944 images, the classification accuracy for 4 types of samples was 92%.
Optimization of the stereo system calibration parameters for photogrammetric measurements in the conditions of field experiments
Authors: Pinchukov V V , Shmatko E V , Bogachev A D , Yu Poroykov A 
Published: December 2021

Abstract
Optical methods for deformation diagnostics and surface shape measurement are often used in scientific research and industry. Most of these methods are based on the triangulation of a set of two-dimensional points from different images corresponding to the three-dimensional points of an object in space. Triangulation is based on the stereo system calibration parameters, which are determined before the experiment. Measurements during conditions with increased vibration loads can lead to a change in the relative position of the cameras of the stereo system (decalibration). This leads to a change in the actual calibration parameters and an increase in the measurement error. This work aims to solve the problem of increasing the measurement accuracy of the photogrammetric method in the case of high vibration loads. For this, it is proposed to use an optimization algorithm for calibration parameters to minimize the reprojection error of three-dimensional points calculated using triangulation. The paper presents the results of a computer simulation of decalibration of a video camera stereo system, an algorithm for optimizing the external parameters of a stereo system, and an assessment of its performance.
Energy efficiency of lighting systems based on acousto-optic filtration
Authors: Beliaeva A S , Romanova G E 
Published: December 2021

Abstract
Designing systems with an acousto-optical filter requires considering its small numerical aperture and crystal size. These features lead to the low efficiency of using the luminous flux, which may be crucial in practical applications of such systems for spectral analysis. The article discusses ways to increase the energy efficiency in different types lighting systems based on acousto-optic filtration.
Acousto-optic devices using acoustic waves refraction
Authors: Polikarpova N V , Chizh I K 
Published: December 2021

Abstract
The methods of acousto-optics provide multiple techniques for controlling optical beam. The technical parameters of corresponding acousto-optic devices are largely determined by the efficiency of acoustic waves generation. In present work we examine the features of elastic waves generation in materials used in acousto-optics. In most of practical applications the elastic wave generation process is implemented through the refraction of elastic waves at the boundary between two anisotropic media. We present a detailed study of the refraction of elastic waves in strongly anisotropic media. We report new refractive effects such as “extraordinary” refraction. In the latter case the change in the direction of the incident acoustic wave does not influence the direction of the energy flow propagation for refracted elastic waves. The configuration of an acousto-optic device using the geometry of unusual refraction in an anisotropic medium is discussed.
Prediction of life time of high-power IR laser diode by resolution of its spectrum to single-mode components
Authors: Berezovskaya N V , Bliznyuk V V , Dolgov A V , Parshin V A , Savinov N S , Selivanov A A , Semenova O I , Tarasov A E 
Published: December 2021

Abstract
The paper proposes a method for predicting the service life of high-power laser diodes used in optoelectronic measuring systems which allow adjusting the thermophysical parameters of the diagnosed flow volume in a certain range of their values. The method based on the analysis of the current dependence of the shape of the line enveloping the laser radiation spectrum after 200 hours of their operation. It is shown that for such an analysis the emission spectrum must be considered as a superposition of the emission spectra of single-mode laser diodes.
Three-dimensional mapping of the optical centers in the bulk of natural diamond by photoluminescent spectroscopy
Authors: Stsepuro N G , Kovalev M S , Krasin G K , Danilov P A , Kudryashov S I 
Published: December 2021

Abstract
Optically active defects in natural diamonds form specific spectral bands in the optical absorption and luminescence spectra and are called optical centers. Optical centers in the visible spectral range and their corresponding defects are called color centers. Spectral absorption and luminescence bands usually occupy several tens of nanometers in the spectral range and often have a complex structure. This spectral structure is unique to each optical center. The stationary broadband UV-MIR characterization of the set of optically active defects in the bulk of natural diamond with a widely varying concentration of impurities was carried out in this work. Comparison of the initial and modified impurity-defect structures of near-surface diamond layers was carried out by the method of cathodoluminescence and cathodoluminescence topography.
Specifics of application of videogrammetric system Vic-3D in aerodynamic experiment
Authors: Gorbushin A R , Kuruluk K A , Kulesh V P , Shvardygulov G E 
Published: December 2021

Abstract
The main objective of this work was testing a possibility of application of commercial videogrammetric system Vic-3D for measuring position and deformation of the aircraft model and its elements in an industrial the TsAGI transonic wind tunnel T-128. The object of research was a model of passenger aircraft with a wingspan of 2010 mm, fixed on the rear sting. The Vic-3D system used for measuring the position and deformation of the aircraft model was applied for the runs with and without flow at the pitch angles range from −
3 to +12 degrees. Model was tested in wind tunnel up to Mach number M = 0.853. An algorithm of working with the Vic-3D system was described in the article, some specifics of obtained results were underlined. An additional program to derive bend and twist deformations of a wing was developed. Results of an experiment were given, errors and inaccuracy were analyzed. Recommendations for using the system Vic-3D in an aerodynamic experiment were given.
Self-oscillations that cause the destruction of intermolecular bonds in the water coolant of a nuclear power plant
Authors: Proskuryakov K N , Anikeev A V 
Published: December 2021

Abstract
The digital acoustic model of a nuclear reactor (DAMNR) is presented as an auto-oscillatory system belonging to a special class of nonlinear dissipative systems capable of generating undamped oscillations. It is established that a water-water power reactor with a turbulent flow of a coolant is an open system of high complexity with a large number of elements, the connections between which are not predetermined, but probabilistic. Elements of the coolant circuit with negative dissipation (negative friction) are identified. It is shown that they self-organize chaotic turbulent pulsations and vortices into ordered wave oscillations, the frequency of which is determined by the Thomson (Kelvin) formula. In radio engineering circuits, an electronic self-oscillating generator with transformer feedback has similar properties. The presence of negative resistance in nonlinear dynamical systems leads to self-organization of chaotic turbulent perturbations and generation of self-oscillations in the form of acoustic standing waves (ASW). On the basis of theoretical and experimental data, the reliability of a previously unknown property of a reactor with connected pipelines - the ability to generate several ASW simultaneously-was confirmed. The use of DAMNR in the design and operation of nuclear power plants allows to identify the sources of ASW occurring in the coolant, the conditions for their occurrence and frequency.
Study and quantitative assessment of the structural inhomogeneities parameters of composite materials
Authors: Chichigin B A , Kokurov A M , Subbotin D E 
Published: December 2021

Abstract
The possibility of determining the size of the delamination region and the depth of its location in non-metallic multilayer weakly conductive materials using a unique pulsed eddy-current equipment by scanning the sample and registering the region of increasing amplitude of the differential signal has been practically confirmed. The nonstationary thermal and holographic interferometry method is used to obtain information on the shape and size of the bundles. For experimental testing, samples were used made of carbon fiber composite materials with artificially created defects in the structure of the material in the form of delaminations of various sizes and shapes.
K-means clustering of zebrafish embryos images acquired with AOTF-based hyperspectral microscope
Authors: Burlakov A B , Shirokov S V , Huang C C , Khokhlov D D 
Published: December 2021

Abstract
Model organism studies are widely implemented in biomedical research fields. Zebrafish is a common and convenient model organism. To provide in vivo investigation of living zebrafish the non-invasive imaging methods are implemented. Hyperspectral imaging utilizing acousto-optic tunable filters is a perspective modality for zebrafish embryos and larvae automated observation. In this paper, the hyperspectral microscope based on the acousto-optical tunable filter is described. Using the hyperspectral image arrays obtained with the described setup, the K-means clustering algorithm is tested. The results obtained for different number of clusters are presented and discussed.
Physiologically based control of the process of gentle light awakening
Authors: Fedortsov A B , Silivanov M O 
Published: December 2021

Abstract
The well-being of a person and the efficiency of his production activities are largely determined by the correspondence of the biorhythms of a person to his working schedule. As it was established at the molecular and genetic level, the main physical factor that allows us to control human biorhythms is light (Nobel Prize 2017). Modern studies of ophthalmologists have found a third type of photoreceptors in human eyes, in addition to rods and cones. These receptors are not intended for receiving images, but primarily for correcting biorhythms, including controlling the process of awakening. The third type of receptors are sensitive mainly in the short-wave, blue region of the visible spectrum. In recent years light-emitting diodes have appeared. However, these devices do not take into account the current requirements for the spectrum of the awakening radiation, and even more so do not allow it to be adjusted during the awakening process according to the necessary program. We offer a technology for gentle awakening of the employee, based on modern concepts of ophthalmology and biorhythmology. The technology uses computer control of the physical factors of awakening-light and sound.
Orthogonal ray scheme: a method for processing interference patterns and reconstructing the shape of a test convex mirror
Authors: Gavlina A E , Novikov D A , Askerko M V 
Published: December 2021

Abstract
This report is devoted to the processing of the interference pattern of the tested mirror, obtained using the orthogonal ray scheme, where the convex testing surface is illuminated by a collimated beam, which is perpendicular to the optical axis of the surface. The interference pattern is created by two wavefronts, one of which is reflected from the mirror, while the other wavefront bypasses the mirror and travels directly to the detector plane. The result of interference pattern processing is a topography map formed by several tangential profiles. The proposed method is suited for large diameter convex spherical and aspherical mirrors and does not require a priori information of surface under the test, such as the vertex radius of curvature and the conical constant. Theoretical foundation of the data processing method are presented.
Radiation hardness of PantherPix hybrid pixel detector
Authors: Dudas D. , Kafka V. , Marcisovsky M. , Neue G. , Marcisovska M. , Prusa P. , Koniarova I. , Semmler M. 
Published: December 2021

Abstract
Hybrid pixel detectors (HPD) are nowadays well known and
widely used in fundamental research, e.g. in high energy physics
experiments. Over the last decade, segmented semiconductor detectors
have also found use in medicine. The total doses received by medical
radiation detectors often reach a significant level (up to several
hundreds of kGy per decade), especially in applications such as
transmission portal in-vivo dosimetry. Such doses might affect
detector properties. Therefore, it is necessary to evaluate their
performance after absorbing a significant radiation dose. PantherPix
is a novel 2D hybrid pixel detector which is designed specifically
for use in radiation therapy. As was concluded in earlier studies,
it is suitable for radiotherapy quality assurance (QA) and portal
dosimetry. In this paper, the PantherPix radiation hardness is
investigated using a 60Co source. The dependence on dose of the
full depletion voltage, leakage current, detector power consumption
and detector response are provided. The PantherPix radiation
tolerance has been shown to be adequate for common cumulative doses
delivered to radiation detectors in radiotherapy over several
decades and its performance has been verified for doses up to 3000
kGy.
A portable cosmic ray detector for school education
Authors: Bomben L. , Capelli S. , Fanzini C. , Lutsenko E. , Mascagna V. , Petroselli C. , Prest M. , Ronchetti F. , Selmi A. , Vallazza E. 
Published: December 2021

Abstract
This article describes the design, assembly and
characterization of a portable cosmic ray detector, developed by the
INSULAB group and suitable for teaching activities aimed at high
school students. It consists of a compact aluminum suitcase
containing three plastic scintillator modules coupled to
photomultipliers, readout by a custom compact electronics chain and
powered by a power bank. The modules operate in coincidence and the
system records the arrival time of each particle and the time over
threshold of the signal of each scintillator module. The data are
acquired and processed by a Raspberry PI connected to a touch screen
display for online monitoring. The procedure implemented for the
determination of the detector efficiency is reported, along with the
results of the measurements of the cosmic ray rate as a function of
the altitude and the zenith angle, performed in the laboratory and
in different locations outdoors.
Experimental 3-dimensional tracking of the dynamics of a single
electron in the Fermilab Integrable Optics Test Accelerator (IOTA)
Authors: Romanov A. , Santucci J. , Stancari G. , Valishev A. , Kuklev N. 
Published: December 2021

Abstract
We present the results of experimental studies on the
transverse and longitudinal dynamics of a single electron in the
IOTA storage ring. IOTA is a flexible machine dedicated to beam
physics experiments with electrons and protons. A method was
developed to reliably inject and circulate a controlled number of
electrons in the ring. A key beam diagnostic system is the set of
sensitive high-resolution digital cameras for the detection of
synchrotron light emitted by the electrons. With 60–130 electrons
in the machine, we measured beam lifetime and derived an absolute
calibration of the optical system. At exposure times of 0.5 s, the
cameras were sensitive to individual electrons. Camera images were
used to reconstruct the time evolution of oscillation amplitudes of
a single electron in all 3 degrees of freedom. The evolution of
amplitudes directly showed the interplay between
synchrotron-radiation damping, quantum excitations, and scattering
with the residual gas. From the distribution of measured
single-electron oscillation amplitudes, we deduced transverse
emittances, momentum spread, damping times, and beam
energy. Estimates of residual-gas density and composition were
calculated from the measured distributions of vertical scattering
angles. Combining scattering and lifetime data, we also provide an
estimate of the aperture of the ring. To our knowledge, this is the
first time that the dynamics of a single electron are tracked in all
three dimensions with digital cameras in a storage ring.
Remark on a promising design of the fissionTPC cathode
Authors: Fu J.Q. 
Published: December 2021

Abstract
The fission Time Projection Chamber (fissionTPC) has been
designed and built to make precision cross-section measurements of
neutron-induced fission by the NIFFTE Collaboration. The signal of
the cathode is implemented as trigger for the fissionTPC that
rejects alpha signal as background and selects only fission fragment
signal to be recorded. This short note is devoted to a discussion of
a promising way to improve the cathode signal performance by
segmenting the planar cathode into two parts. It is shown through
analytic calculations that the new cathode structure has better
signal-to-noise ratio and faster rise time.