bluuebunny/crossref_metadata_2025 huggingface dataset:
Adaptive noise reduction for power Doppler imaging using SVD filtering in the channel domain and coherence weighting of pixels
Authors: Pialot Baptiste , Lachambre Célestine , Mur Antonio Lorente , Augeul Lionel , Petrusca Lorena , Basarab Adrian , Varray François
Published: December 2022

Objective. Ultrafast power Doppler (UPD) is an ultrasound method that can image blood flow at several thousands of frames per second. In particular, the high number of data provided by UPD enables the use of singular value decomposition (SVD) as a clutter filter for suppressing tissue signal. Notably, is has been demonstrated in various applications that SVD filtering increases significantly the sensitivity of UPD to microvascular flows. However, UPD is subjected to significant depth-dependent electronic noise and an optimal denoising approach is still being sought. Approach. In this study, we propose a new denoising method for UPD imaging: the Coherence Factor Mask (CFM). This filter is first based on filtering the ultrasound time-delayed data using SVD in the channel domain to remove clutter signal. Then, a spatiotemporal coherence mask that exploits coherence information between channels for identifying noisy pixels is computed. The mask is finally applied to beamformed images to decrease electronic noise before forming the power Doppler image. We describe theoretically how to filter channel data using a single SVD. Then, we evaluate the efficiency of the CFM filter for denoising in vitro and in vivo images and compare its performances with standard UPD and with three existing denoising approaches. Main results. The CFM filter gives gains in signal-to-noise ratio and contrast-to-noise ratio of up to 22 dB and 20 dB, respectively, compared to standard UPD and globally outperforms existing methods for reducing electronic noise. Furthermore, the CFM filter has the advantage over existing approaches of being adaptive and highly efficient while not requiring a cut-off for discriminating noise and blood signals nor for determining an optimal coherence lag. Significance. The CFM filter has the potential to help establish UPD as a powerful modality for imaging microvascular flows.
Effects of AlN/GaN superlattice buffer layer on performances of AlGaN/GaN HEMT grown on silicon for sub-6 GHz applications
Authors: Hieu Le Trung , Hsu Heng-Tung , Chiang Chung-Han , Panda Debashis , Lee Ching-Ting , Lin Chun-Hsiung , Chang Edward Yi
Published: December 2022

In this study, the effects of AlN/GaN superlattice (SL) thickness on performances of AlGaN/GaN high electron mobility transistor (HEMT) heterostructure grown by metal-organic chemical vapor deposition on silicon is investigated. Stress in GaN is controlled by varying the total thickness of the AlN/GaN SL. Improved crystal quality and surface roughness accomplished with 2200 nm-thick AlN/GaN SL, leads to an increase in high electron mobility (1760 cm2 (V s)−1) as well as two-dimensional electron gas concentration (1.04 × 1013 cm−2). AlGaN/GaN metal–insulator-semiconductor HEMT (MIS-HEMT) fabricated on the heterostructure with SL buffer layer exhibits a significant improvement in maximum saturation current of 1100 ± 29 mA mm−1 at V
GS = 0 V and a low on-resistance of 4.3 ± 0.15 Ω mm for the optimized AlN/GaN SL. The 2200 nm-thick AlN/GaN SL supports the growth of stress-free GaN heterostructure, which can reduce the insertion loss for sub-6 GHz radio frequency (RF) applications. This GaN HEMT structure based on SL buffer layer is suitable for low-frequency RF power applications.
Impact of ion implantation and laser processing parameters on carrier lifetimes in gold-hyperdoped silicon
Authors: Dissanayake Sashini Senali , Chow Philippe K , Lim Shao Qi , Yang Wenjie , Fiutak Rhoen , Williams Jim S , Warrender Jeffrey M , Sher Meng-Ju
Published: December 2022

In recent years, infrared photodetectors using silicon hyperdoped with deep-level dopants started to demonstrate extended light detection beyond the silicon’s absorption edge. The reported responsivities or external quantum efficiencies, however, are typically low. Focusing on gold-hyperdoped silicon and using time-resolved terahertz spectroscopy, a non-contact photoconductivity measurement, we investigated how hyperdoping parameters affect charge carrier lifetimes. Correlating the observed lifetime characteristics with dopant distribution profiles, we identify factors that impact carrier lifetime most significantly. Specifically, the charge carrier lifetime reduces with increasing gold concentrations, increasing ion implantation energies, and increasing pulsed-laser melting fluences. Both ion implantation energy and laser fluence affect the dopant incorporation depths. The total gold dose implanted and laser fluence affect the carrier distribution profile, particularly the concentration spike toward the surface. Oxide passivation and the number of laser pulses do not impact the carrier lifetime significantly. Our findings benefit future device developments.
Exploring the structural and magnetic trends in Ba0.9Sm0.1Fe12−xAlxO19 M-type Hexaferrites
Authors: Asif Sana Ullah , Ranjha Qasim Ali , Ghori Ubaid-ur-Rehman , Nisa Mehrun , Ahmad Muhammad Saeed , Bukhari Mehak , Jabeen Nawishta , Hussain Ahmad , Hassan NajamUl , Ahmed Fahim
Published: December 2022

The current study describes the structural and magnetic properties of Ba0.9Sm0.1Fe12−x
Al
x
O19 (x = 0.0, 0.5, 1.0, 2.0, 3.0) M-type hexaferrites. The conventional ceramic route was implied to prepare all the nominal samples. Morphological analysis suggested the non-presence of secondary phases as well as the formation of the hexaferrites material. X-ray Diffraction technique was used for structural analysis from which microstructural parameters are calculated and discussed. Magnetic properties are measured at room temperature. The saturation magnetization (Ms) and coercivity (Hc) values show a cyclic and converse trend for synthesized samples. Firstly, a decrease in Ms and an increase in Hc was observed up to intermediate dopant incorporation and becomes converse for higher doping levels. The maximum coercivity and minimum magnetization are observed for Ba0.9Sm0.1Fe11Al1O19. The c/a and Mr/Ms ratio suggest the formation of perfect M-type hexaferrites. This work suggests that synthesized material is a good option for magnetic applications e.g., transformer and inductor cores, microwave devices, recording heads, and magnetic shielding.
Stochastic formalism for U(1) gauge fields in axion inflation
Authors: Fujita Tomohiro , Mukaida Kyohei , Tada Yuichiro
Published: December 2022

We develop the stochastic formalism for U(1) gauge fields that has the Chern-Simons coupling to a rolling pseudo-scalar field during inflation.
The Langevin equations for the physical electromagnetic fields are derived and the analytic solutions are studied. Using numerical simulation we demonstrate that the electromagnetic fields averaged over the Hubble scale continuously change their direction and their amplitudes fluctuate around the analytically obtained expectation values.
Though the isotropy is spontaneously broken by picking up a particular local Hubble patch, each Hubble patch is understood independent and the isotropy is conserved globally by
averaging all the Hubble patches.
Pair production in inhomogeneous electric fields with phase modulation
Authors: Hu Li-Na , Amat Orkash , Li Lie-Juan , Mohamedsedik Melike , Xie B S
Published: December 2022

Electron-positron pair production in spatial inhomogeneous electric fields with sinusoidal phase modulation is studied within the Dirac-Heisenberg-Wigner formalism. The focus is on discussing the effects of the modulation parameters on the momentum spectrum and the reduced particle number at various spatial scales. For the momentum spectrum, the interference effect becomes more and more remarkable with the increase of modulated amplitude or frequency, while the symmetry is severely destroyed with modulated amplitude. For the reduced particle number, it is greatly enhanced by about a few times and evenly one order of magnitude when modulation parameters are applied. Moreover, the effect of spatial scales on the reduced particle number is carefully examined, and it is found that it increases rapidly at small spatial scales, while it tends to be a constant at large spatial scales. We also obtain the optimal pair production that can be achieved through different modulations. These results can provide a possibility for realizing the optimal pair production by combining the advantages of field spatial inhomogeneity with different choices of phase modulation.
Ridge regression energy levels calculation of neutral ytterbium (Z = 70)
Authors: Yu Yushu , Yang Chen , Jiang Gang
Published: December 2022

In view of the difficulty in calculating the atomic structure parameters of high-Z elements, the Hartree–Fock with relativistic corrections (HFR) theory in combination with the ridge regression (RR) algorithm rather than the Cowan code’s least squares fitting (LSF) method is proposed and applied. By analyzing the energy level structure parameters of the HFR theory and using the fitting experimental energy level extrapolation method, some excited state energy levels of the Yb I (Z = 70) atom including the 4f open shell are calculated. The advantages of the ridge regression algorithm are demonstrated by comparing it with Cowan code’s LSF results. In addition, the results obtained by the new method are compared with the experimental results and other theoretical results to demonstrate the reliability and accuracy of our approach.
Size effect on light propagation modulation near band edges in one-dimensional periodic structures
Authors: Tang Yang , Wang Jiajun , Zhao Xingqi , Li Tongyu , Shi Lei
Published: December 2022

Periodic photonic structures can provide rich modulation in propagation of light due to well-defined band structures. Especially near band edges, light localization and the effect of near-zero refractive index have attracted wide attention. However, the practically fabricated structures can only have finite size, i.e., limited numbers of periods, leading to changes of the light propagation modulation compared with infinite structures. Here, we study the size effect on light localization and near-zero refractive-index propagation near band edges in one-dimensional periodic structures. Near edges of the band gap, as the structureʼs size shrinks, the broadening of the band gap and the weakening of the light localization are discovered. When the size is small, an added layer on the surface will perform large modulation in the group velocity. Near the degenerate point with Dirac-like dispersion, the zero-refractive-index effects like the zero-phase difference and near-unity transmittance retain as the size changes, while absolute group velocity fluctuates when the size shrinks.
Genuine Einstein–Podolsky–Rosen steering of generalized three-qubit states via unsharp measurements
Authors: Chen Yuyu , Guo Fenzhuo , Wei Shihui , Wen Qiaoyan
Published: December 2022

We aim to explore all possible scenarios of (1 → 2) (where one wing is untrusted and the others two wings are trusted) and (2 → 1) (where two wings are untrusted, and one wing is trusted) genuine tripartite Einstein–Podolsky–Rosen (EPR) steering. The generalized Greenberger–Horne–Zeilinger (GHZ) state is shared between three spatially separated parties, Alice, Bob and Charlie. In both (1 → 2) and (2 → 1), we discuss the untrusted party and trusted party performing a sequence of unsharp measurements, respectively. For each scenario, we deduce an upper bound on the number of sequential observers who can demonstrate genuine EPR steering through the quantum violation of tripartite steering inequality. The results show that the maximum number of observers for the generalized GHZ states can be the same with that of the maximally GHZ state in a certain range of state parameters. Moreover, both the sharpness parameters range and the state parameters range in the scenario of (1 → 2) steering are larger than those in the scenario of (2 → 1) steering.
Non-Markovianity of an atom in a semi-infinite rectangular waveguide
Authors: Zeng Jing , Song Yaju , Lu Jing , Zhou Lan
Published: December 2022

We investigate the non-Markovianity (NM) of a waveguide QED with a two-level atom as the system and a semi-infinite rectangular waveguide as the environment, where the transverse magnetic (TM
mn
) modes define the quantum channels of guided photons. The perfect mirror imposed by the finite end exerts a retarded feedback mechanism to allow for information backflow, which leads to NM dynamics. For the energy separation of the atom far away from the cutoff frequencies of transverse modes, the delay differential equations are obtained with single-excitation initial in the atom. Our attention is focused on the effects of multiple quantum channels involved in guiding photons on the degree of non-Markovian behavior. An asymptotic value of the non-Markovianity

N
1

can be found as the atom–mirror distance is large enough, however, the asymptotic value of

N
2

of the atom interacting with the effective double-modes is lower than that of the atom interacting with the effective single-mode. We also show that

N
1

is a constant, and the analytical expression for

N
2

is related to the parameters associated with the modes, which is related to the interference of the two modes.
Development and analysis of coatings cavitation erosion model by controlling changes in the acoustic properties of liquid media in limited volumes with resonant dimensions
Authors: Khmelev V N , Barsukov R V , Golykh R N , Barsukov A R
Published: December 2022

The article considers the influence of the extent of cavitation wear of materials and their coatings on the acoustic properties of the sounded liquid media in a limited volume. The model of an liquid media bounded by a volume with resonant dimensions is considered based on an electromechanical analogy system. The parameters and characteristics of the sounded liquid media most sensitive to changes in the dimensions of the volumes confining them as a result of their cavitation erosion are determined.
Onomasiological modeling in the information field
Authors: Bolbakov R G , Sinitsyn A V , Ya Tsvetkov V
Published: December 2022

The article investigates onomasiological modeling in the information field. It briefly describes the information field as an integral model of reality. It is shown that there are more relations in the information field than in reality. This ensures the integration of models. Onomasiological modeling is based on the transfer of linguistic methods to computer science. The article introduces the notion of “onomasiological information modeling”. The peculiarity of onomasiological information modeling is that it allows to realize simultaneously three kinds of modeling: semantic, systematic, and descriptive. To realize this possibility, onomasiological information modeling must include three groups of information units: semantic, systemic, and descriptive.
Assessment of the concentration of wear products of bearing elements
Authors: Juraeva Gulchehra , Djabbarova Mukaddas
Published: December 2022

The article presented by the author considers the greatest wear along the arc of the contact of the bearing ring with the ball is observed on the surface where there is more slippage, i.e. on the face of the groove of the rings. The problem often lies in the low durability of the bearing supports. The authors of this article are invited to analytically evaluate the durability of the bearing with additional consideration of the regularity of changes in the concentration of wear products in the oil of the unit. Uneven load distributions and different elastic constants of materials used for the outer ring and balls, and further with the subsequent improved correction of the resource, which are carried out in accordance with modern requirements. Such a correction involves not only taking into account the impact of lubrication conditions and oil contamination on the bearing life, but also modifying the resource in relation to the fatigue stress limit to the dynamic equivalent load, taking into account many factors of influence.
Mathematical model for estimation the characteristics of the noise immunity
Authors: Mehdiyeva Almaz , Quliyeva Sevinj
Published: December 2022

The important issues or the data transmission systems are the harmful effect of various sources of interference in the communication channel and problem of increasing noise immunity in conditions of linear distortion in development of modern systems. In order to improve the reliability of an accuracy characteristics of receiving of information, a mathematical model for assessing the stability to interference with incoherent receiving in telecommunication systems operating under the influence of unintentional interference sources is proposed. The mathematical model takes into account the quality of communication, spectral efficiency, modulation scheme and coding method when providing multimedia services to users.
Mathematical model of hardening the disk-shaped saw teeth with laser beams
Authors: Abrorov Akbar , Kurbonov Fazliddin , Teshaev Mukhsin , Kuvoncheva Matluba , Saidov Khasan
Published: December 2022

The mathematical model of hardening the disk-shaped saw teeth with laser beams has been developed, and in terms of results of theoretical research based on this mathematical model, it has shown that it is advisable to use laser heat treatment technology for disc saws. At the same time, elements with a larger mass are less likely to collide with an increase in mass during operation. If the mass of the element increases by two times, the probability of collision decreases by three times. In general, it has been known that thermal treatment of the material with laser beams reduces the probability of damage to the saw teeth by 1.33 times, which in turn leads to an increase in the service life of saws. Graph of the dependence of changes in microhardness when load resistance is increased by changing the specific parameters by sharpening disc saw materials using laser beams has been developed. The 3D image shows the load resistance of the saw material, the mass of the element acting on it and the connection of its impact surface. Surfaces exposed to strong impact are four times smaller than the standard material with increased material strength, i.e. resistance to hard elements is increased by four times.
Measuring setup for determining the parameters of materials that absorb radio waves
Authors: Samoylov A G , Friedman O A
Published: December 2022

A measuring complex for determining the coefficients of reflection and transmission of electromagnetic radiation through radio-absorbing materials has been developed and manufactured. Measurements are made by the direct method by comparison with a reference material. When measuring the transmission of radio waves through an absorbing material, the standard is air, and when measuring the reflection of radio waves, a sheet of steel is used as the standard. When measuring the transmission of radio waves through an absorbing material, the standard is air, and when measuring the reflection of radio waves, a sheet of steel is used as the standard. The installation uses replaceable horn antennas and standard microwave generators. The distance necessary for carrying out measurements in the far field of antenna radiation was determined and the maximum sizes of the irradiation spots of the measured materials for various frequencies in the range from 1 to 20 GHz were calculated. A measurement setup that is efficient in terms of the “price-quality” criterion is made, easy to maintain and does not require computational work.
Experience in studying natural fractals
Authors: Belashev B Z
Published: December 2022

We investigate the fractal characteristics of diverse natural objects and discuss their possible applications. Fractal dimensions of the suture lines of ammonite shells, granite textures, the portions of the river network in the Onega and the Ladoga lakes basin and the multi-fractal spectra of varved clay sedimentation in these lakes were calculated. It is shown that the fractal dimensions of the suture lines of shells can be used to identify ammonites. Fractal textures of granites can be applied to improve their aesthetic perception. The fractal parameters of the river network and the sedimentation regimes in the lakes may be related to tectonics.
Improving the wear resistance and durability of cultivator tools
Authors: Tulaganova Laziza , Yunushuzhaev Saidakbarkhyzha , Juraeva Gulchehra
Published: December 2022

In this article the existing methods to improve the wear resistance of working elements of agricultural machinery are highlighted and analyzed in detail. The relevance of this problem for domestic producers and consumers of agricultural machinery is the fact that the service life of many elements of domestic agricultural machinery is 1.2-2.0 times lower than similar imported machines. This means that imported machines operate twice as long before repair than our machines. The paper analyses the causes of wear and loss of the cultivator tines’ serviceability. The wear factors causing gradual changes in the size and shape of the working tools, which subsequently lead to the loss of operability, are considered. The data obtained as a result of their study, can be used in the development of technological processes to restore the working bodies of tillage machines.
Development of an equalizer using singular value decomposition
Authors: Lantsov V N , Melnik I S
Published: December 2022

The problems of wireless communication systems are investigated. A model and hardware implementation of a system for estimating and correcting amplitude distortions of a radio signal using an algorithm based on Singular Value Decomposition (SVD) has been developed. The analysis of the efficiency of the system when processing the LTE signal is performed. The model was obtained in the Matlab system with modeling the propagation environment, as well as time and frequency tuning blocks using the LTE Toolbox library. FPGA resources with hardware implementation are estimated. Testing the signal-to-noise ratio of the two-antenna equalizer revealed its advantage over the single-antenna configuration by 2.8 dB.
Determination of the degree of microbiological damage to the «Cement Concrete - Steel Reinforcement» system
Authors: Strokin K B , Novikov D G , Konovalova V S
Published: December 2022

The degree of corrosion damage by microorganisms to the concrete wall of the basement is investigated. The biofilm on the surface of the concrete wall under study is formed by micromycetes Aspergillus niger, bacteria Bacillus subtilis, Actinomycetes, nitrifying bacteria Nitrosomonas, lactic acid bacteria Lactobacillus and sulfate-reducing bacteria Desulfovibrio. The waste products of microorganisms consist of organic acids secreted by micromycetes of Aspergillus niger, ammonium ions, carbonate-, nitrate-, sulfide-ions secreted by bacteria. To establish the corrosion state of steel reinforcement in biodegradable concrete, the electrode potential was measured. The established values of the surface potential of steel reinforcement are in the range -351 ÷ -376 mV. This suggests that the probability of local corrosion of steel reinforcement in a biodegradable concrete wall is strong. It will take about 20 years to achieve an aggressive concentration of organic acids at the surface of steel reinforcement in biodegradable concrete with a layer thickness of 5 cm. However, in conditions of constant moistening of the concrete surface, this period is reduced to 10-11 years. The predicted rate of local corrosion of steel reinforcement in concrete exposed to microorganisms is at least 0.2 mm/year. It was found that the depth of concrete destruction under the influence of microorganisms, mainly micromycetes Aspergillus niger, for 20 years is 1.3 cm; for 50 years is 2.1 cm.
The leak detection process modeling
Authors: Makarov V A , Korolev F A
Published: December 2022

The paper describes formalized description concept of the expiration gas process through product manufacturing defects in the control of tightness: Model Internal description based on the use of parameters of circuit theory and mathematical model of the external description made by means of functional expansions obtained on the basis of mathematical models experimental research of the implemented software package external description. A dynamic model of the outflow of gases through product defects is presented by the Wiener-Voltaire equations. The proposed method for studying the outflow of gases through product defects consists a simulation object whose input is subjected to an external action with constant other variable parameters and registration of the output signal. The experimental data are compared with the results of theoretical calculations based on the molecular model of the outflow process.
Stationary deformation of cylindrical shells with viscoelastic filler
Authors: Safarov I I , Teshaev M X , Boltayev Z I , Nuriddinov B Z , Ruziyev T R
Published: December 2022

The task of determining the dynamic response of plates and shells to moving loads is very relevant. The purpose of this work is to study the stationary deformation of infinitely long cylindrical shells with viscoelastic filler when moving along the axis of the shell of a wave of normal pressure with up to resonant velocity under the influence of normal moving loads. The paper presents a mathematical formulation of the problem, developed methods of solution and obtained numerical results. The solution methods are based on the joint application of the integral Fourier transform in the axial coordinate and the decomposition of all given and desired values into Fourier series in the angular coordinate. An effective algorithm for solving the problem has been developed and implemented on a computer. It is established that with the distance from the point of application of force along the circumference of the voltage for all considered cases, the sign changes. If the connection is one-sided, then tensile stresses arise, and the shell will detach from the filler. It has also been found that changes in the stiffness and rheological properties of the filler in the considered range have little effect on the length of the contact zone.
Study of heat transfer in models of FCC, BCC, SC and DEM porous structures with different porosities
Authors: Soloveva O V , Solovev S A , Talipova A R , Shakurova R Z , Paluku D L
Published: December 2022

In the present work, we investigated the effect of the geometry of the open cell foam material on the value of the pressure drop and heat flux. We create models of porous media with an ordered (FCC, BCC, SC) and disordered (DEM) structure with different values of material porosity: 0.7; 0.75; 0.8. Numerical modeling was carried out in the ANSYS Fluent software (v. 19.0) for various air flow velocities. At material porosities of 0.7 and 0.75 there is a noticeable increase in pressure drop in BCC and FCC packings, respectively. This is due to the features of creating the geometry of these packings. At material porosity of 0.8, the largest pressure drop corresponds to the packing of FCC cells. The structures show approximately the same heat flux value at air flow velocities of 0.01 and 0.05 m/s. At material porosity of 0.7 at velocities of 0.25-1.25 m/s, the largest values show the BCC packing. At material porosities 0.75 and 0.8, the values above correspond to the packing of FCC cells. The lowest heat flux values in SC cell packaging are observed at all investigated porosities. Also, the SC packing has the lowest pressure drop values and, therefore, the highest energy efficiency values.
Analysis of the impact effect of a piece of cotton with a flat surface with a multi-sided grates slope
Authors: Djuraev Anvar , Sayitkulov Sardor , Rajabov Ozod , Kholmirzaev Javlon , Haydarov Bakhtiyor
Published: December 2022

In the cotton ginning unit recommended in the article, the impact effects of multi-faceted gutters on flat sloping surfaces of cotton pieces in large waste ginning zones have been theoretically studied and connection graphs have been constructed. The results of the numerical solution of the problem, based on the analysis of the obtained analytical solutions, recommended the appropriate values of system parameters to increase the efficiency of cleaning cotton from large wastes in all three zones of the cleaning unit.
Morphological properties and atomic crystal lattice of solid carbonaceous objects
Authors: Rossokhin A V , Lopatin O P , Pushkarenko N N , Alatyrev S S
Published: December 2022

Diesel particulate matter (DPM) is an area of concern from an environmental point of view due to its functionality to settle in the respiratory channels when inhaled, cause inflammation in the respiratory tract, accumulate carcinogenic compounds, and adversely reflected the cardiovascular functions, thus causing excess mortality. DPM consists of an agglomeration of a numerous unions of preimages germ structures, spherical in the form of turbostratic carbon. Part of the DPM contains partially oxidized polyaromatic compounds C and H with a ring structure (PAH).
Mathematical model for pointing and holding the energy signal of a solar space power plant
Authors: Barkova M E , Zhukov A O , Kartsan I N , Klimov D I , Kuznetsova V O
Published: December 2022

One of the main problems of solar space power plants is the high-precision guidance and direction retention of the energy transmission device. High-precision guidance and retention of an energy signal requires the development of both the guidance and retention system as a whole, and the mathematical apparatus for its description. The article proposes a mathematical description of the pointing and holding method through continuous scanning.
Experimental study of pressure loss in hybrid cooling tower with finned tube radiator
Authors: Kharkov V V , Madyshev I N , Kuznetsov M G , Galimova A T , Sagdeev A A
Published: December 2022

The paper deals with the problem of enhancement of cooling of recycled water in industry. The authors developed a new design of a hybrid cooling tower with a fill pack consisting of inclined-corrugated contact plates and a tube radiator. The water flow during the cooling process flows inside the radiator to avoid direct contact with air, preventing the biofouling process. In addition, the external surface of the tube radiator is modified by finning for heat transfer intensification. The purpose of the work was an experimental study of the pressure losses in the developed hybrid cooling tower. The relationship of the pressure drop through the dry fill pack from the average air velocity was determined. The maximum increase in hydraulic losses for the dry fill pack with finned tubes of the radiator is less than 4.5% at the average air velocity of 7 m/s compared to the smooth tubes. Furthermore, it was found that when the wetting density is less than 28.3 m3/(m2·h), a drift of water droplets from the hybrid cooling tower can be decreased.
On the determination of the elastoplastic state of a plane made of an anisotropic material with an elliptical hole
Authors: Derevyannykh E A , Maksimov A N , Morozova N N , Nikitin A V , Yaruskina E T , Samsonov A M
Published: December 2022

The elastic-plastic position of a plane made of an anisotropic material with an elliptical hole is considered. Anisotropy is the ability of a crystal to express different qualities in different directions. The presence of this quality in its simplest form can be observed only in single crystals. In polycrystals, the anisotropy of the body is basically (macroscopically) unable to be expressed in any way due to the random orientation of the microcrystals, or it does not manifest itself at all, except for special cases. With an ordered arrangement of chemical particles, the forces of interaction between them and the interatomic distances turn out to be unequal, and this is precisely the reason for the anisotropy of crystals. Another reason may be the asymmetry of its molecules. The material of the work is an integral element of the task of studying the effect of anisotropy on the stress-strain state of various structures and bodies.
Viscometer for investigating the viscosity of magnetic fluid media
Authors: Bolotov A N , Novikova O O , Novikov V V
Published: December 2022

The rational application of magnetic fluids in various technical systems requires their stability analysis, hydrodynamic particle size, dissipative processes in the colloid control. The existing viscometers do not fully meet all requirements, in particular, they do not allow research in a magnetic field of given magnitude and certain topography. It is proposed to determine rheological properties of magnetic fluids using rotary viscometer, in which two measuring gaps are structurally designed and filled with studied fluid, which is important for calculating characteristics of low viscosity magnetic media. The device design implements practically homogeneous magnetic field, varying within wide range and directed perpendicular to liquid shear stress. The device allows to steadily maintain shear rate in medium under study, and to determine viscosity with a sufficiently large change. A small magnetic fluid volume is required to estimate rheological characteristics. The accuracy of measurements of the internal friction force, device heating temperature, coaxial cylinders rotation speed and magnetic field inside investigated medium meet the requirements of international standards. Laminar fluid flow process in the device gap is described mathematically. This made it possible to justify the construction geometrical dimensions in order to increase the measurements and determine rheological properties of low-viscosity magnetic materials. The formulas for calculation of Newtonian fluid viscosity coefficient, shear stress and shear rate based on experimental data were obtained.
Vibration anode-abrasive polishing of channels of small cross section
Authors: Trifanov V I , Nikitina L N , Saraeva K V , Malizhonok D I , Trifanov I V
Published: December 2022

The mechanism of anodic dissolution of microroughnesses in the combined method of anodic-abrasive vibratory polishing with magnetic-abrasive electrically polarized charged grains of channels of pipes of small cross section made of non-magnetic materials is presented. Materials that can be used as magnetic-abrasive composite grains such as Fe3C, FeB, FeB2, etc. or magnetic NbC-Fe modified with graphene, carbon nanotubes, or a combination thereof have been selected. A passivating electrolyte used in this combined method of vibration anode-abrasive polishing, for example, 3% NaNO3 + (3-6)% Fe3C, is proposed. The article shows the developed scheme of the process of combined magnetic-abrasive polishing and describes the process itself. The value of the allowance to be removed can be estimated from the proposed formula for calculating the removed layer of microroughness in the joint electrochemical process of polishing the channel surface with stationary and pulsed currents flowing in the electrolyte flow.
Mathematical modeling of the liquefied gases hydrates formation
Authors: Shostak Nikita , Zaporozhets Evgeny
Published: December 2022

A model of the formation of hydrates in the system of phase states of liquefied gas - water (ice, liquid, vapor), which is in a stratified state or in the form of emulsions, is presented. The relationship between the amount of liquefied gas components transferred into clusters and remaining in the environment is described. The features of the kinetics of the hydrate formation process are reflected. Using the developed mathematical model of the formation of hydrates of single- and multicomponent liquefied gases, it is possible, in a first approximation, to determine the thermobaric parameters, the basic properties and characteristics of the process, which include molecular (molar mass, density and number of moles of hydrates, as well as gas and water in it) and energy (hydrate formation in liquefied gas - water systems) parameters.
Calculate a batch adsorber with a fixed bed of sorbent
Authors: Legkiy Nikolay , Kryventsov Sergey , Shumilin Vladsimir
Published: December 2022

There is considered a method to define parameters for the adsorber with the fixed bed of sorbent. The paper reviews constructional features to clean gas-air mixtures and liquids from toxic contaminants.
Approach to assessment of thermodestructive resistance of polymer-containing finishing building materials
Authors: Chernushevich Elena , Shirinkin Pavel , Bezborodov Yuri
Published: December 2022

The paper presents the review results of the conformity assessment existing system of finishing building materials with safety requirements. It is noted that the existing assessment methods do not take into account the change in the properties of finishing building materials in the temperature range from 40° C to the temperature of their ignition / combustion / smoldering. The aim of the study is to substantiate the approach and develop a method for assessing the thermal destructive resistance of finishing building materials. In this work, a study of the thermal destruction of finishing building materials was carried out, the dependences of the qualitative and quantitative composition of thermal destruction products on temperature were established, and the influence of temperature and time on the dynamics of thermal destruction was determined. On the basis of the data obtained, the criterion of the thermal destructive resistance of finishing building materials was substantiated, a method of assessing the thermal destructive resistance of finishing building materials was developed and their classification was proposed. The developed methodology and classification of finishing building materials can be applied when assessing the fire hazard of finishing building materials; when preparing proposals for regulatory documents and regulatory legal acts with the aim of safer use of finishing building materials; when modeling the development of hazardous fire factors, allowing to take into account the effect of thermal destruction products.
Optimization of wire drawing process in terms of rheological characteristics of stretching material and refinement of die hole geometry
Authors: Khaimovich Irina , Khaimovich Aleksandr
Published: December 2022

The article discusses the improvement of the analytical method for calculating the wire drawing force, taking into account the rheological properties of the material being pulled and clarifying the geometry of the die hole, provides a new analytical model for calculating the drawing force, describes the algorithm for calculating the drawing force, analyzes the results of modeling the drawing process for round products.
Influence of the process parameters of incremental forming of personified implants of the cranial bones on their geometry
Authors: Erisov Yaroslav , Nikolaenko Andrey , Petrov Ilya , Surudin Sergei , Kolsanov Alexandr
Published: December 2022

This work, on the basis of experimental data, establishes a relationship between the incremental forming process parameters and the accuracy of the resulting geometry of personalized implants of the cranial bones. The authors carried out a qualitative and quantitative assessment of the values of the maximum deviation, mean average deviation and standard deviation. It was determined that the use of two passes with incremental forming does not provide an increase in the geometric accuracy of the obtainable implant. The accuracy of the obtainable products increases with a reduction in the step of movement of the deforming tool during incremental forming.
Surface saturation monitoring of forming products from titanium alloy VT20 with additives
Authors: Gadalov Vladimir , Vornacheva Irina , Luchinovich Anastasia , Loparev Dmitry , Scherbakov Alexander , Malikov Vladimir , Sokolova Viktoriia
Published: December 2022

In the publication, the saturation of the surface of a large size of stamped articles made of VT20 alloy with interstitial impurities and the formation of non-metallic compounds on it were investigated. The process of gas saturation in several directions depending on external parameters: heating temperature, medium, holding time is analyzed.
Methods for studying the optical properties of transparent conducting oxides synthesized on the basis of tin dioxide
Authors: Zinchenko Timur , Pecherskaya Ekaterina , Gurin Sergey , Kozlov Gennady , Zhurina Angelina , Shepeleva Anastasia
Published: December 2022

For transparent conducting oxides, the most important characteristics are electrical and optical parameters, which are interconnected. The article presents a study results of the optical properties of transparent conducting oxides based on tin dioxide obtained by spray pyrolysis. To study the transparent conducting oxides parameters, the method of pointwise unconditional minimization and the Tauc model were used.
Comprehensive study of changes in the phase composition of copper-aluminum conductors during heating
Authors: Yu Pariyskaya A , Mokryak A V , Pyankova L A
Published: December 2022

Changes in the microstructural characteristics and phase composition of copper plated conductors CCA-20 in the temperature range of 100-600 °C were studied by XRD and SEM methods. Fiducial markers for determining the temperature of exposure to conductors are the appearance of the Al2Cu phase at the phase boundary of the conductor at temperatures above 300 °C and the existence of the Al4Cu9 phase in the temperature range of 300-400 °C.
Synthesis of thin-film layers of electrochromic panels based on SnO2 and WO3 by aerosol pyrolysis
Authors: Zinchenko Timur , Pecherskaya Ekaterina , Gurin Sergey , Kozlov Gennady , Zhurina Angelina , Shepeleva Anastasia
Published: December 2022

Energy efficiency and energy saving are actively developing. One of the promising areas of optoelectronics is the improvement of electrochromic panels or smart glasses. Smart glasses are divided into electrochromic, thermochromic and photochromic. The devices incorporate thin-film structures that are transparent conductive oxide (TCO) and transition metal oxide (TMO). An urgent scientific task is a systematic comprehensive study of the parameters of specified thin films, as well as the improvement of methods for their synthesis to obtain coatings with specified properties. A promising and most suitable method for the synthesis of the above-listed coatings is the method of aerosol pyrolysis, which has a number of advantages: ease of implementation and the possibility of embedding into the finished technological process while maintaining the coating quality. The article analyzes the results of the study of the following coatings parameters: the efficiency of coloring; TMO response time; the TCO throughput and conductivity.
Detection of weathering effects and mineral additive content of LDPE composites using hyperspectral imaging
Authors: Metlenkin D A , Kiselev N V , Platov Y T , Tyubaeva P M , Boychenko E A , Burmistrov I N
Published: December 2022

The use of hyperspectral imaging and multivariate analysis to detect weathering effects and mineral additive content in LDPE composites is demonstrated. Principal component analysis of hyperspectral images was used to obtain models of composite gradation by additive content and presence of weathering effects. The analysis of the factor loading matrix of spectral wavelength reflectance coefficients revealed the most significant bands contributing to the gradation of composite samples by additive content and presence of weathering effects.
Modification of a metal surface with detonation diamond nanoparticles
Authors: Malikov Vladimir , Tihonskii Nikolay , Kozlova Victoria , Shevtsova Lilia , Ishkov Alexey
Published: December 2022

Friction between metal surfaces in various mechanisms is an actual problem in modern engineering. Friction causes wearing of the rubbing parts. For reducing the coefficient of friction, it is proposed to treat the surfaces of rubbing parts with a suspension having a high (more than 20%) content of ultradispersed detonation diamond (UDD). In the course of treatment, nanodiamond particles penetrate into the substance being treated and create a thin surface layer (up to 1000 nm, depending on the degree of part processing), which leads to smoothing the effect of microsliding, due to which the reduction of the friction coefficient. The resulting surface layer consists of a metal matrix with diamond nanoparticles embedded in it. The paper shows the study of the steel part surface with the use of the optical and X-ray methods, and provides information on the change in the coefficient of friction of steel parts.
Nonlocal model of velocity vibrations compressed fluid under conditions hydraulic impact
Authors: Stefanyuk E V , Gavrilova T E , Uglanov D A , Panova V A , Shimanov A A
Published: December 2022

Taking into account the relaxation properties of the fluid, a hyperbolic equation of motion is obtained that describes the change in velocity under conditions of nonlocal equilibrium, that is, taking into account the effect of unsteadiness of the flow on the magnitude of the friction force. Studies of its exact analytical solution have shown that taking into account the nonstationarity of tangential stresses leads to results that differ significantly from the solutions of the classical hyperbolic equation obtained by using the values of velocity, density, tangential stresses, and pressure averaged over the flow cross section (the hypothesis of quasi-stationarity). Comparison of the obtained solution with experimental data, as well as with the results of theoretical studies of other authors (I.A. Charny), obtained from the solution of the Navier - Stokes equations (equations for local quantities), showed their satisfactory agreement. Consequently, studies based on the theory of quasi-stationarity can be used only after comparing them with the results obtained taking into account the nonstationarity of tangential stresses (friction force) or with experimental data, that is, only after determining the range of the degree of nonstationarity in which it can be used.
Multilayer thin-film resistive structures with temperature self-compensation for super-precision resistors and strain gauges
Authors: Gurin Sergey , Pecherskaya Ekaterina , Novichkov Maksim , Safronova Olga
Published: December 2022

The paper presents the main structural and topological solutions, the technology of obtaining and stabilizing multilayer thin-film resistive and tensoresistive structures with temperature self-compensation, which allows achieving a TCR value of no more than ± 1 × 10−6 and an instability of resistance no more than ± (0.01 … 0.02) %.
Diagnosis of a periodic nanostructure with a defect using circularly polarized light
Authors: Yatsyshen V V
Published: December 2022

The paper considers the reflection of a circularly polarized light wave from a periodic nanostructure. The method of characteristic matrices was used to calculate the ellipsometric parameters ρ
0 and Δ of reflected light. It is shown that a wave initially polarized in the left circle changes polarization upon reflection, turning into an elliptically polarized wave. The results obtained for an ideal periodic medium are compared with the results of reflection from a periodic medium with a single defect - the upper layer of the original periodic medium is replaced by an absorbing dielectric layer. The analysis showed that the spectral dependences of the ellipsometric parameters for two structures, periodic and defective, differ significantly. In the range of wavelengths λ from 0.4 μm to 0.6 μm, the ellipsometric parameter ρ
0 for the considered periodic medium and the medium with a defect differ significantly from each other - where the maximum is for one medium, there is approximately the minimum for the other. In turn, the parameter Δ demonstrates a significant difference for the two structures in the wavelength range λ from 0.46 μm to 0.55 μm. The use of circularly polarized light demonstrates wide possibilities for studying defects in periodic nanostructures.