bluuebunny/crossref_metadata_2025_split huggingface dataset:
Investigation of the tangential discontinuities formation in the glycerol under shear load
Authors: Efremov D V , Chudinov V V , Uvarov S V 
Published: February 2021

Abstract
The work is devoted to the study of the formation of tangential discontinuities of glycerol parameters under shear load. The studies were carried out using a modified coaxial cylinder viscometer. The experiment was inspired by the work of Ya. I. Frenkel, in which it was noted that “… liquids, being condensed media, should exhibit effects that are more characteristic of solids than gases …”, while the thermodynamic and kinetic properties should be determined by structural “variables”, traditional for both “liquid” and solid state. These studies will further help in explaining the anomalous momentum transfer regimes caused by the mechanisms of instability that are realized under the conditions of the “decay” of multiple metastable states, usually observed under intense (dynamic and shock-wave) loading in liquids and solids.
Numerical simulation of slow deformation perturbations in fault zones
Authors: Kazakbaeva A A , Smolin I Yu 
Published: February 2021

Abstract
Over the past half a century, the concept of slow deformation waves of the Earth has been developed and widely discussed in the Earth sciences. The velocity of slow waves is considered to be 5–6 orders of magnitude less than the velocity of sound and 7–8 orders of magnitude greater than tectonic flows. Analyzing and classifying various manifestations of slow deformation waves in the geomedium accumulated over forty years V. G. Bykov identifies two types of autowaves in his review—inter-fault and intra-fault. Here, the process of generation and propagation of slow deformation disturbances between two faults in an elastoplastic medium is studied numerically. The faults were defined as narrow elongated soft areas inclined to the axis of the load application. Just in these faults plastic deformation was permitted to generate. The simulations proved that the fronts of deformation waves head towards each other at approximately the same velocities, their shapes being close to planar but slightly curved.
Influence of grain size on the nucleation and development of plasticity in nanocrystalline FeNi films
Authors: Korchuganov A V , Kryzhevich D S , Chumakov Y A , Grigoriev A S 
Published: February 2021

Abstract
A molecular dynamics study of the features of the nucleation and evolution of plastic deformation in nanosized nanocrystalline FeNi films under uniform uniaxial tension is carried out. The dependences of the strength properties of the films on the grain size are obtained. It is found that the dependences of stresses at which defects begin to nucleate, maximum strength is achieved and plastic flow is realized, on the grain size have a pronounced maximum. The optimal grain structure for which the nanocrystalline film has the maximum strength at uniaxial stretching is determined. The calculated dependences allow determining the critical grain size at which the Hall-Petch relationship is reversed. It is shown that the nucleation and initial development of plasticity in nanosized films with grain size above the critical one has a dislocation nature. The twinning contribution to the film plasticity increases at strains corresponding to plastic flow.
Peculiarities of the development of plastic deformation in a textured FeNi alloy with a gradient grain structure
Authors: Korchuganov A V , Kryzhevich D S , Chumakov Y A , Grigoriev A S 
Published: February 2021

Abstract
The mechanisms of nucleation and development of plastic deformation in the FeNi alloy with a gradient grain structure with a pronounced axial texture were revealed. The study was carried out on the basis of a molecular dynamics method. The simulated sample contained four layers, each of which consisted of grains of approximately the same size. The sample was subjected to uniform uniaxial tension at a constant rate in the direction of the grain misorientation axis. It was found that initially plastic deformation develops only in the layer with the largest grains and represents an abrupt growth of stacking faults. This process ends with the hardening of the deformed sample. At higher deformations, smaller grains contribute to the development of plasticity. At the same time, an almost ideal crystal structure can be restored in large grains, and twinning occurs in medium-sized ones.
Comparative Analysis of Mechanical Properties of Laminated Carbon Fiber Reinforced Composites Based on PEEK and PI Matrices
Authors: Kosmachev P V , Alexenko V O , Panin S V 
Published: February 2021

Abstract
The mechanical properties of laminated carbon fiber reinforced composites based on PEEK and PI matrices have been studied. Various schemes of carbon fiber lay-outing were employed. Flexural stress-strain curves, optical images of fracture surfaces and SEM micrographs of composite structure were analyzed. It has been shown that laminated composites reinforced with continuous unidirectional fibers according to layout scheme [0°/0°] possessed the maximum values of mechanical properties (flexural modulus and bending strength) under three-point bending. PEEK based composites exhibited 2 times higher flexural strength in contrast to PI based ones (0.4 GPa and 0.2 GPa, respectively), while the modulus of elasticity in bending was 4 times larger (61 GPa and 15 GPa, respectively).
Some approaches for residual porosity estimating
Authors: Kosyanov D Yu , Zavjalov A P , Vornovskikh A A , Zakharenko A M , Liu X , Li J 
Published: February 2021

Abstract
Several approaches for materials residual porosity assessment are presented in this paper. Importance of development of accurate model is shown based on Al2O3–Ce:YAG and Al2O3–Ce:(Y,Gd)AG ceramic phosphors taken as model objects. The evaluated difference in the outcomes of different methods applied for estimating porosity has been shown to be as high as ∼40%. The obtained results become applicable to another types of inclusions within the studied volume of a material as in the models under consideration the main role is given to a geometrical perspective of the problem.
Development of methodological approaches for non-destructive testing of welded joints of steel finned panels by the active thermography method
Authors: Kotovshchikov I O , Yakovlev Ju O , Prohorovich V E 
Published: February 2021

Abstract
This paper examines methodical approaches to non-destructive testing (NDT) of thin steel T-welded joints made by ultrasound welding. The choice of the active thermography method is justified. Numerical parameters were developed for characterize the operational properties of the plate-fin heat exchanger and the results of finned panel inspection by the active thermography method. These parameters were compared and the correlation was found. The developed methodological approaches will be useful in the future for developing an NDT technique that allows detecting internal defects in welded seams which decrease breaking load and worsen the operational properties of products made by finned panels.
Microstructure, electromechanical hysteresis and polarization characteristics of solid solutions of the system (Na, K, Cd0.5) NbO3
Authors: Moysa M O , Andryushin K P , Shilkina L A , Nagaenko A V , Andryushina I N , Reznichenko L A 
Published: February 2021

Abstract
The phase diagram of the system (1-x-y) NaNbO3 – xKNbO3 – yCdNb2O6 (y=0.25, x=0.05÷0.20) is constructed. The agreement between the microstructure and the phase diagram of the system is demonstrated. A decrease in the polarization characteristics up to the phase transition temperature is detected. The formation of extrema d33
(E) in the region of the inflection point on the ascending branch of the half-period S33
is revealed. A correlation has been established between the internal structure (crystalline, domain, grain, defect), fundamental electromechanical and polarization properties for solid solutions of the studied system.
Features of protolytic reactions in the ground and exited states in the presence of cationic polyelectrolyte
Authors: Mugabutaeva A S , Naumova A O , Melnikov P V , Zaytsev N K 
Published: February 2021

Abstract
Protolytic reactions in the ground and excited states for 2-naphthol and its sulfo derivatives were studied. It was revealed that in the presence of cationic polyelectrolyte, the acidity constant of the protolytic reaction in the ground state shifts to a more acidic region. It was also found that the value of the shift depends on the number of sulfo substituents in 2-naphthol derivatives. It reaches 1.2 units for the disodium salt of 2-naphthol-3,6,8-trisulfonic acid. At the same time, no significant effect of the polyelectrolyte on the acidity constant in the excited state pKa* was observed, and the photoprotolytic reaction proceeds in the same way as for an unimmobilized substance.
Size Effects and Mechanisms in the Friction and Wear Processes of Ceramics Based on Zirconium Dioxide
Authors: Pirozhkova T S , Zhigachev A O , Korenkov V V , Tyurin A I 
Published: February 2021

Abstract
This paper presents a study of the tribological properties of ceramics based on ZrO2 stabilized with CaO in a ceramic-ceramic friction pair. The influence of the scale factor on the coefficient of friction in the micro- and nanoscale is established. A qualitative correlation of the theoretical and experimental curves is shown for friction coefficient dependence on the body-counterbody contact force. Friction and wear micromechanisms at a micro- and nanoscale are proposed for the investigated TZP ceramics.
Formation of high-entropy alloy by methods of ion-plasma technologies
Authors: Prokopenko N A , Petrikova E A , Shugurov V V , Petykevith M S , Ivanov Yu F , Uglov V V 
Published: February 2021

Abstract
Multi-element equiatomic single-phase thermodynamically stable substitutional solid solutions (high-entropy alloys) have a unique combination of mechanical, tribological, physical and other properties. The purpose of this research is to develop an ion-plasma method for the formation of high-entropy alloys. A method for the formation of high-entropy alloys has been developed, which consists in the deposition of a multi-element metal plasma on a substrate in a vacuum. Plasma is formed by vacuum-arc plasma-assisted simultaneous independent sputtering of the cathodes of the selected elements. The modes allowing synthesizing thin Ti-Al-Nb-Zr films with a composition close to equiatomic were revealed. The presence of droplet fraction particles of various elemental composition in the films was found. It is shown that the phase composition of the films depends on the concentration of elements in the plasma.
Studies of water treatment influence on the structure of vein quartz from shungite rocks
Authors: Rigaeva Y L , Rozhkova N N , Ekimova T A 
Published: February 2021

Abstract
The article presents the results of the research of the structure and composition of one of the morphological varieties of quartz – vein quartz of shungite rocks from Zazhogino deposit of Karelia and a reference quartz sample. The values of the crystal lattice parameters were determined by full-profile analysis (Rietveld method). Coherent scattering region (CSR) for vein quartz samples are determined using the Debye-Scherrer formula after applying the background subtraction function. The influence of water treatment on the content of impurity elements in samples of vein quartz was also studied. The most common impurity elements in natural vein quartz samples, such as Al, Na, Li and Ge, are identified. It is shown that water treatment is effective for reducing the content of impurity elements and obtaining the minimum size of vein quartz crystallites.
Dislocation structure and phase composition of Ti13Nb13Zr after high-pressure torsion
Authors: Rudenya E A , Ivanov I V , Ognev A Yu , George A M 
Published: February 2021

Abstract
The approach based on synchrotron X-ray diffraction was applied in this research to investigate the dislocation and phase structures of severely deformed disk of Ti13Nb13Zr alloy. It was found, that the final structure of the material is inhomogeneous along the disk diameter. The local area of highest dislocation density of α′-phase matches with the zone of passed deformation-induced phase transformations.
Deformation of silumin subjected to a pulsed electron beam treatment
Authors: Rygina M E , Ustinov A M , Petrikova E A , Klopotov A A , Ivanov Yu F , Teresov A D , Abzaev Yu A , Loskutov L M , Volokitin G G 
Published: February 2021

Abstract
Using a virtual extensometer, it was found that irradiation with a pulsed electron beam (18 keV, 15 J/cm2, 200 μs, 3 pulses, 0.3 s−1) leads to an increase in the strength properties of the hypoeutectic silumin samples by 30%. The deformation curves in the coordinates «σ-ε» and «σ - √ε» did not reveal inflection points that characterize the stages of deformation transformation of the material. This indicates that the transitions from stage to stage in this class of materials are blurred.
The Investigation of the Structure and Properties of Nonwoven Fibrous Materials Based on Polyhydroxybutyrate Biopolymer
Authors: Tyubaeva P M , Zykova A K , Morokov E S , Olkhov A A , Podmasteriev V V , Popov A A , Iordanskii A L 
Published: February 2021

Abstract
Currently, the development and research of nonwoven medical fibrous materials based on biopolymers is an area of a great practical interest. One of the most promising methods for producing nonwoven materials with a highly developed surface is electrospinning (ES). In the article, the possibility of effective sterilization of ultrathin fibers based on polyhydroxybutyrate (PHB) by the ozone treatment was considered. The purpose of this work was to establish the interrelation between changes in the ES process and accompanying changes in the supramolecular structure, morphology, physical and mechanical properties of the fibrous materials based on PHB.
Plant extract assisted synthesis of reduced graphene oxide sheet and the photocatalytic performances on cationic and anionic dyes to decontaminate wastewater
Authors: Ghosh Sanjukta , Das Piu , Baskey (Sen) Moni 
Published: February 2021

Abstract
Green synthesis of reduced graphene oxide (RGO) has gained momentum over chemical methods due to its environmental compatibility. The present study deals with the green synthesis of the RGO sheet using the bark extract of Alstonia scholaris by the simple heating method in less time duration. Different characterizations such as x-ray diffraction (XRD), ultraviolet-visible (UV-Vis) spectroscopy, Fourier-transform infrared (FTIR) spectroscopy confirm the formation of RGO and the transmission electron microscopy (TEM) study shows that the synthesized material is a few-layered RGO sheet. The result of the photoluminescence (PL) study explores the partial reduction of graphene oxide (GO). The photocatalytic activities of the synthesized product were investigated via photo-degradation of methylene blue (MB) and methyl orange (MO). The results show that the synthesized RGO is more fruitful in cationic dye (MB) degradation than that of anionic dye (MO) depending on the electrostatic interaction between RGO and the dyes. The rate of photocatalytic performance of the nanocomposite on MB dye is 40 times greater than that of MO dye.
Preparation and properties of controllable aluminum foam
Authors: Sun Leilei , Wang Yanli , Wang Lucai , Wang Fang , Xu Hong , Huang Wenzhan , You Xiaohong 
Published: February 2021

Abstract
As an important method for preparing aluminum foam, space holders have the advantages of simple preparation process, controllable porosity, high operation safety, easy to realize the large-scale production and so on. In this paper, sodium thiosulfate (Na2S2O3) is selected as the new raw material for spacer to replace the traditional spacer (such as urea and salt), which is prepared by melting, injecting into the mold and solidifying. Three kinds of spherical spacer with different diameters were modified, and aluminum foams with three porosity (65%, 70% and 75%) and three pore sizes (Ø2mm, Ø3mm and Ø4mm) were prepared by compaction, dissolution and sintering. The results of metallographic analysis of aluminum foam sintered sample show that the aluminum powder particles bond closely above 600 °C. The quasi-static compression results show that the interaction between aluminum matrix materials and pore structure affects the mechanical properties of foamed aluminum, and the interaction between porosity and pore size affects the mechanical properties of foamed aluminum.
Oblique propagation of nonlinear ion-acoustic cnoidal waves in magnetized electron–positron–ion plasmas with nonextensive electrons
Authors: KHALID Muhammad , ULLAH Ghufran , KHAN Mohsin , AHMAD Sheraz , NABI Sardar , KHAN Daud 
Published: February 2021

Abstract
Theoretical investigation of nonlinear electrostatic ion-acoustic cnoidal waves (IACWs) is presented in magnetized electron–positron–ion plasma with nonextensive electrons and Maxwellian positrons. Using reductive perturbation technique, Korteweg–de Vries equation is derived and its cnoidal wave solution is analyzed. For given plasma parameters, our model supports only positive potential (compressive) IACW structures. The effect of relevant plasma parameters (viz., nonextensive parameter q, positron concentration p, temperature ratio σ, obliqueness l
3) on the characteristics of IACWs is discussed in detail.
Electric-field induced fluctuations in laser generated plasma plume
Authors: AHMED Rizwan , JABBAR Abdul , UMAR Zeshan Adeel , BAIG Muhammad Aslam 
Published: February 2021

Abstract
The effect of an external electric field on laser-generated plasma has been studied. It is observed that the laser-generated plasma can be used for the ignition of a spark in the presence of a low voltage external electric field. An eight-fold emission intensity enhancement in Cu I spectral lines are measured as compared to the signal intensity in the absence of an external electric field. The plasma parameters remain the same initially, up to a few microseconds after the generation of plasma, and this feature makes it more interesting for the quantitative analysis of any sample using laser induced breakdown spectroscopy (LIBS). In the presence of an external electric field, fluctuations (contraction and expansion) in the laser-generated plasma are observed which increase the plasma decay time and consequently result in enhanced signal intensity.
Multiple current peaks and spatial characteristics of atmospheric helium dielectric barrier discharges with repetitive unipolar narrow pulse excitation
Authors: ZHOU Xiangyu , WANG Qiao , DAI Dong , HUANG Zeen 
Published: February 2021

Abstract
Atmospheric dielectric barrier discharges driven by repetitive unipolar narrow pulse excitation are investigated numerically by using one-dimensional fluid models. The one-dimensional simulation focuses on the effects of applied voltage amplitude, pulse repetition frequency, gap width and γ coefficient on the multiple-current-pulse (MCP) discharge. The results indicate that the MCP behavior will lead to the stratification of electron density distribution in axial direction. Traditional MCP manipulating methods, such as reducing the applied voltage amplitude, increasing the applied voltage frequency, adjusting the gap width, cannot regulate MCPs exhibiting in this work. Further analyses reveal that the increasing electric field of the cathode fall region is the basis for the emergence of MCP behavior.
Occupational Exposure to Second-Hand Tobacco Smoke: Development of a Job Exposure Matrix
Authors: Dobson Ruaraidh , Demou Evangelia , Semple Sean 
Published: February 2021

Abstract
Exposure to second-hand tobacco smoke (SHS) in the workplace has been largely controlled in most workplaces in many countries that have adopted smoke-free laws and regulations. Workers in offices, bars, restaurants, and many other settings have experienced substantial reductions in the frequency and intensity of their exposure to SHS. While current exposure to SHS of most non-smoking adults arises from living with a smoker there are likely to be some jobs where non-negligible exposure to SHS continues to occur. This study describes the development of a simple job exposure matrix (JEM) for SHS exposure for the UK working population in 2020 and identifies that at least 1.04 million workers are likely to be exposed to SHS while performing their job. Occupations with the highest frequency and intensity of exposure include those where workers carry out work tasks in private, domestic settings: including care workers and home carers. This SHS-JEM provides a novel method for assessing occupational exposure to SHS in other countries, and can act as a tool to identify priorities for policies to protect those workers who continue to be at risk from SHS.
Deep embedded clustering with multiple objectives on scRNA-seq data
Authors: Li Xiangtao , Zhang Shixiong , Wong Ka-Chun 
Published: February 2021

Abstract
In recent years, single-cell RNA sequencing (scRNA-seq) technologies have been widely adopted to interrogate gene expression of individual cells; it brings opportunities to understand the underlying processes in a high-throughput manner. Deep embedded clustering (DEC) was demonstrated successful in high-dimensional sparse scRNA-seq data by joint feature learning and cluster assignment for identifying cell types simultaneously. However, the deep network architecture for embedding clustering is not trivial to optimize. Therefore, we propose an evolutionary multiobjective DEC by synergizing the multiobjective evolutionary optimization to simultaneously evolve the hyperparameters and architectures of DEC in an automatic manner. Firstly, a denoising autoencoder is integrated into the DEC to project the high-dimensional sparse scRNA-seq data into a low-dimensional space. After that, to guide the evolution, three objective functions are formulated to balance the model’s generality and clustering performance for robustness. Meanwhile, migration and mutation operators are proposed to optimize the objective functions to select the suitable hyperparameters and architectures of DEC in the multiobjective framework. Multiple comparison analyses are conducted on twenty synthetic data and eight real data from different representative single-cell sequencing platforms to validate the effectiveness. The experimental results reveal that the proposed algorithm outperforms other state-of-the-art clustering methods under different metrics. Meanwhile, marker genes identification, gene ontology enrichment and pathology analysis are conducted to reveal novel insights into the cell type identification and characterization mechanisms.