bluuebunny/crossref_metadata_2025_split huggingface dataset:
Strain state agrogenic soil under its interaction with a deep ripper
Authors: Rashidov T , Djuraeva N B , Atamirzayev M , Normuminov B 
Published: August 2020

Abstract
The cultivated soil environment changes its structure and is deformed; therefore, the considered model of the processes of interaction of the working body with soil remains understudied. The influence of soil criteria on the working body behavior can be taken into account through its density and tensile strength. To describe the movement of the soil near the leg during finite deformations, a plastic medium model proposed by academician Kh.A. Rakhmatulin and simplified equations obtained on the basis of the hypothesis of flat sections were used. When using the model of linearly elastic and compressible plastic medium, the resistance forces of the soil medium are determined when the legs of the subsoiler, presented in the form of a circular cone, move. It has been established that the magnitude of this force substantially depends on the type of contact conditions between the body and the soil, and its greatest value is achieved in the case of continuous motion. The dependence of the resistance force on time is obtained. According to the results of graph analytical studies, it is obvious that at the initial stage, while the contact area of the circular cone with the soil is variable, the resistance force depending on time changes according to a parabolic law, and then it remains constant. In the case of the movement of the subsoiler leg at a constant speed, it was found that, depending on the coefficient of internal friction and soil traction, a zone of increased soil density can form near the working body of the cultivator, where there is a significant increase in resistance force. With an increase in the angle of internal friction, a slight decrease in the resistance force is observed. The calculations were carried out based on the methods of mechanics of a deformable solid, soil mechanics, and were performed in the Maple-8 programming environment.
CFRP composites for strengthening wooden structures
Authors: Gribanov A S , Strekalkin A A , Kudryatseva A A , Zdralovic N 
Published: August 2020

Abstract
The purpose of this work is to study the strength of wooden beam structures with local modification of wood in the compressed zone. To achieve this goal, the physical and mechanical characteristics of modified wood were determined using modifiers based on ed-20 epoxy-diane resin, urea-formaldehyde resin, and dimethacrylic polyester. The best physical and mechanical characteristics were obtained for samples using dimethacrylic polyester: the ultimate strength was 84 MPa, the elastic modulus was 21 GPa. The increase in strength compared to solid wood was 46%, and the increase in the modulus of elasticity was 54%. Tests of beam structures with a span of 4.5 m and a cross section of 100×200 mm with local modification of wood in the compressed zone with a polymer composition based on dimethacrylic polyester were carried out. The increase in the strength of beams with local modification in the compressed zone compared to solid wood was 11% within the design loads, and the increase in stiffness by 18%. The “load-strain” relationships are constructed based on the test results. It is established that the greatest effect can be achieved when using external reinforcement systems together in a stretched zone by reducing the influence of defects and defects in beam structures and local modification of the extremely stressed compressed zone.
Influence of laser treatment mode on the friction coefficient and wear of bearing steel
Authors: Morozov Valentin , Gusev Vladimir 
Published: August 2020

Abstract
The article considers the influence of input factors of the laser processing: the radiation power, the longitudinal feed of the laser beam and the distance from the protective glass of the focusing head to the workpiece on the friction coefficient and absolute wear of steel SHH15SG. The greatest influence on the output parameters (friction coefficient and absolute wear) has the power of laser radiation, as it increases, the wear of the surface layer decreases. The obtained multi-factor models and graphical interpretation of the experiment results allow us to assign a laser treatment mode that provides the demanded wear of the treated surface layer of bearing steel. The developed method of assigning the laser processing mode reduces the auxiliary time of the technological operation and eliminates the need for additional experiments in production conditions. The results of the research are useful for manufacturing enterprises that implement laser processing processes, as well as for design organizations that develop modern laser equipment.
Multiple-factor model of hardness of steel 40H13 after laser processing
Authors: Gusev Vladimir , Morozov Valentin , Gavrilov Dmitry 
Published: August 2020

Abstract
The multiple-factor experiment is planned and made, and the hardness of the chromic steel 40H13, which is subjected to laser processing on a multibeam laser complex, is determined. Samples in the form of a cylinder 7 mm long and with a diameter of 30 mm are exposed to laser processing. Hardness of the processed surface layer of samples was measured by means of the Micro-Combi Tester installation of CSM Instruments (Switzerland). The independent entrance factors of process, which significantly impact on operational indicators of the processed surface layer, are chosen: power of laser radiation, longitudinal feed of laser beam and a distance from protective glass of a focusing head up to the processed surface. As a result of performance of the plan of a multiple-factor experiment and statistical data processing of a planning matrix the regression equations, which connect the optimization parameter with independent factors, having the interactive and dominating impact on formation of physic-mechanical characteristics of quality of the processed surface layer are received. On the basis of the received multiple-factor model and its graphic interpretation the appointment and optimization of modes of the laser processing, which provides the required values of hardness of a surface layer, is possible.
Dehydration factor upon activation of building sand by ultraviolet radiation
Authors: Pavlov A N , Gol’Tsov Yu I , Mailyan L R , Stel’Makh S A , Shcherban’ E M 
Published: August 2020

Abstract
The analysis of the influence of ultraviolet irradiation of building sand, which is a filler in a concrete mixture, on the dependence of the strength of concrete on the content of the filler. With an increase in the sand content due to the hydrophilicity of the surface of its particles in the mixture, the amount of free water necessary for hydration of the cement and the formation of cement stone decreases. Along with a decrease in the content of binder cement, this factor is an additional reason for the decrease in concrete strength with increasing sand content. Ultraviolet irradiation leads to dehydration of the surface of sand particles and the appearance of hydrophobic centers. With the increase in the hydrophobicity of sand in the concrete mixture, the content of free water available for cement hydration increases, and the strength of the cement stone increases. The change in the hydrophobicity of the surface of sand particles depending on the irradiation time is nonmonotonic. Therefore, there is an optimal ultraviolet activation mode that provides the greatest increase in concrete strength.
Deep levels model identification in semiconductor barrier structures
Authors: Krylov Vladimir , Tatmyshevskiy Konstantin , Bogachev Aleksey 
Published: August 2020

Abstract
Semiconductor barrier structures are essential elements of modern integrated electronics. The band theory explains properties of barrier structures using deep levels in the semiconductor band gap. The relentless interest in studying the characteristics of deep levels is due to practical needs, ambiguous interpretations and scatters of experimental results obtained by different researchers. In order to increase the accuracy of the measurements, a modified capacitive deep-level transient spectroscopy technic of has been developed. A mathematical model of the hardware transformations of the barrier structure capacitance transient signal is developed and provided in this article. The model considers the nonexponentiality of the capacitance transient and the spectrometer hardware transformations nonlinearity. There are the results of the deep levels experimental studies in silicon diodes and the model parametric identification. The technic makes it possible to reduce by five or more times the six-sigma confidence interval for the discrete deep level activation energy determining in comparison with the round robin test results of ASTM F978-02.
Optimization of laser melting parameters of martensity-aging steel powder
Authors: Voznesenskaya A A , Kochuev D A , Kireev A V , Zhdanov A V , Raznoschikov A S 
Published: August 2020

AbstractIn this work, we investigated the possibility of manufacturing parts by selective laser melting of heat-resistant steel. The study of the structural-phase composition of the powder material by X-ray spectroscopy was carried out, and the particle size distribution was studied by scanning electron microscopy. Powder material was melted at an industrial facility for selective laser fusion, and the parameters of laser melting were optimized for experimental samples. Information on the nature of the current melting processes was obtained as a result of analyzing the geometric characteristics of laser irradiation zones. The structure of the formed material, pores and microcracks were revealed using metallographic analysis.
Topological layered nanostructures with controlled functional characteristics induced by laser radiation on a solid surface
Authors: Arakelian S M , Evstyunin G A , Kucherik A O , Bukharov D N , Khudaberganov T A , Zhirnova S V , Shamanskaya E L , Butkovsky O Ya 
Published: August 2020

Abstract
Models of the formation of roughnesses on the surface of materials and the movement of distributed flows in their presence are considered, which ultimately determines the functional properties of such topological materials of different compositions induced by laser radiation. The paper also presents simulation of crystallization of complex structures from a melt with an analysis of the morphology of the resulting crystalline structures, and shows examples of the occurrence of fractal dendritic formations. Different types of morphology are induced depending on the energy of the laser radiation and the duration of the heating; determining the final state of objects with the desired functional and structural characteristics. Using the methods of cellular automata, the models were obtained for both the distribution of crystallization centers and the growth of an individual cluster under the influence of diffusion mechanisms. The relationship between the resulting morphology and the modified parameters of the models used is analyzed.
Q-switched mode in laser ceramics with Cr4+ for technological surface cleaning
Authors: Kiselev Alexey V , Pankov Mikhail A 
Published: August 2020

Abstract
A compact solid-state laser based on a Nd:YAG (1 at. %) ceramic active media in the Q-switched mode was studied. Ceramic YAG elements with different concentrations (0.1 to 1 at.%) of Cr4+ doping were used as a Q-switches, 50 to 500 ns pulses were registered with the high energy single pulse. Transparent ceramic obtained by thermosetting sintering. A laser scheme is proposed with a pulse duration and energy setting that contains a composite element for combining the properties of the studied samples of transparent ceramics in one volume. This scheme allows you to implement a compact laser to clean the surface of various materials (glass, concrete, plastic, steel, etc.) from contamination.
Measurement of laser-induced dynamic structures on the surface of materials in a real time scale
Authors: Kazaryan Mishik , Galkin Arkady , Evstyunin Grigorij , Zhirnova Svetlana , Shamanskaya Elena , Arakelyan Sergei 
Published: August 2020

Abstract
The processes induced by laser radiation in the region of its interaction with matter are characterized by a high development rate and exclude direct contact of measuring detectors in the interaction region. The opportunity of structural adjustment of the irradiated surface of the material requires recording the temporal characteristics of these dynamic processes, which essentially determine the structural surface phase transitions in a heterogeneous medium. Therefore, for their diagnostics the highly sensitive, non-contact and inertialess registration methods are required. We used promising in this aspect optical recording methods based on the two channel scheme, i.e. the pump-probe techniques: the power pump laser and additional/probe laser radiation (brightness amplifies) to measure the development of nonlinear dynamic processes on the solid surface under laser radiation. The approach in frame of work of the such unified intelligent laser technological system results in control in time of processes of both laser thermal hardening with corresponding characteristics and generation of the spatial structures of different types on the surface of metallic units. We demonstrated some results for the laser technological processing with powerful laser radiation of a metal surface.
The melting regimes induced controllable by laser radiation on the surface of solids with the diagnostics of arising micro-nanostructures and hydrodynamic instabilities
Authors: Bukharov D N , Kucherik A O , Osipov A V , Antipov A A , Arakelian S M 
Published: August 2020

Abstract
We applied a controlled method for producing nanostructures on glass substrates. We made detailed measurements to control the resulting micro-and nanostructures using as the principal example of surface modification of glassy carbon compositions under laser irradiation. The properties of the samples after laser irradiation were studied using atomic force microscopy (AFM) with an accuracy of about 10 nm in the scanning plane. The results of probing the material modification by the AFM images of its surface have been considered in frame of the nonlinear hydrodynamic mathematical approach and computer simulation.
Granular dynamic structures of different topologies on the surface of solid materials; control of their distribution by laser treatment
Authors: Bukharov D N , Arakelian S M , Butkovsky O Ya , Evstyunin G A 
Published: August 2020

Abstract
The topic is focused on the technological features of the laser radiation action on the surface of metals to study various modes of formation of granular structures, which ultimately determine the functional and structural properties of products being under laser treatment. It is presented the results and algorithms being useful to predict the development of new technological processes on the material surface induced by laser radiation with an appropriate choice of key control parameters for the corresponding phenomena.
Vehicle oscillation taking into account the rheological properties of the suspension
Authors: Yusupov Majid , Rahkmankulova Barna , Ziyaeva Sholpan , Kushaev Akobir 
Published: August 2020

Abstract
The forced oscillations of a four-axle vehicle with a double spring suspension are considered. The motion of a system with six degrees of freedom can be represented with sufficient accuracy by a system with two degrees of freedom. Therefore, the body of the vehicle has two degrees of freedom: sideways movement and wagging (jumping and galloping carts will be neglected). It is assumed that the rheological properties of the spring (suspension) are different and obey the hereditary theory of Boltzmann-Volterra viscoelasticity. As the core of heredity, the Koltunov-Rzhanitsyn core is used, which has weakly singular features of the Abel type. Effective computational algorithms for solving problems based on the use of quadrature formulas have been developed. For numerical calculation, a computer program has been compiled, the results of which are presented in the form of graphs. The influence of the rheological properties of the suspension on the forms of vertical and angular movement of the body is studied. It was found that due to the suspension viscosity, the amplitude of vertical and angular oscillations decreases and the frequency increases.
A method to perform float-and-sink test for separation of coal samples of various densities and determination of ‘Probable Error’ and ‘Imperfection’
Authors: Pradhan Sushobhan , Mohanta Satyabrata 
Published: August 2020

Abstract
This article presents a detail experimental procedure to perform float-and-sink tests for classifying coal samples according to their densities. Moreover, this article emphasizes obtaining ‘partition curves’ for three different coal samples (heavy media bath, big barrel and small barrel), which helps in evaluating and demonstrating classifier performance. Calculations of independent variables such as ‘Probable Error’ and ‘Imperfection’ are also discussed for partition curve that helps in evaluating the effectiveness of various beneficiation equipment used for the upgradation of quality of coal received from different coal mines. It was observed that there is a tendency for the partition curves to steepen as the density of separation decreases. In other words, separations at lower density is sharper than separations at higher density.
Tensions of Transnationalism: Youth Rebellion, State Backlash, and 1968 in Poland
Authors: Fidelis Malgorzata 
Published: August 2020

Abstract
This article looks at Polish students who attempted to challenge the communist state’s hegemony with their own alternative interpretation of leftist politics during the pivotal era of the global sixties. This challenge culminated in student and youth demonstrations in March 1968 and the state’s violent reaction. In contrast to dominant narratives that depict 1968 in Poland and Eastern Europe as primarily shaped by the domestic political context, this article shows Polish students not simply as protesters against a “totalitarian” regime, but as active participants in a contemporary global search for a new kind of leftism. This quest involved turning away from the state as a potential vehicle for a socialist transformation, reformulating ideas of justice and solidarity, and engaging in leftist conversations across borders. The concept of transnational imagination is central to this discussion as both the young people and the state projected different visions of transnational solidarities and were influenced by crises happening elsewhere, including the Vietnam War and the Six-Day War in the Middle East. In Poland, the communist regime deployed and weaponized the transnational imagination against the protesters by launching a powerful antisemitic campaign. Stigmatizing protesters as Zionists and foreign agents alien to the Polish national community, the campaign solidified the racialized understanding of the “Polish nation,” which had lasting political consequences, including the shape of oppositional politics in the 1970s and 1980s.
Invited Commentary: Epidemiologic Methods as Applied to Epidemiology Education—Goals and Expectations to Advance and Diversify the Field
Authors: D’Agostino Emily M 
Published: August 2020

AbstractIn their accompanying article, Brown and Cox (Am J Epidemiol. 2021;190(2):305–312) offer strategies for improving introductory epidemiology instruction in large undergraduate classes using a team-based instructional approach. Effective epidemiology instruction can increase the quality and effectiveness of teaching and learning in our discipline. Recent work has suggested that epidemiology education can also be targeted as a mechanism to fuel equity and progress in the field. In this commentary, I contextualize Brown and Cox’s article within the literature on epidemiology instruction for undergraduates. I also explore the status of methods for measuring teaching and learning effectiveness in our field. I revisit what makes epidemiology a unique science and connect this with instructional strategies that have the potential to capitalize on these features. Lastly, I consider whether our field can improve in developing methods of measuring the effectiveness of epidemiology instruction for achieving these aims. Ultimately, as I suggest, increasing the rigor of methods for evaluating epidemiology instruction will serve to diversify, enhance, and advance our discipline.
Scanning window analysis of non-coding regions within normal-tumor whole-genome sequence samples
Authors: Torcivia J P , Mazumder R 
Published: August 2020

Abstract
Genomics has benefited from an explosion in affordable high-throughput technology for whole-genome sequencing. The regulatory and functional aspects in non-coding regions may be an important contributor to oncogenesis. Whole-genome tumor-normal paired alignments were used to examine the non-coding regions in five cancer types and two races. Both a sliding window and a binning strategy were introduced to uncover areas of higher than expected variation for additional study. We show that the majority of cancer associated mutations in 154 whole-genome sequences covering breast invasive carcinoma, colon adenocarcinoma, kidney renal papillary cell carcinoma, lung adenocarcinoma and uterine corpus endometrial carcinoma cancers and two races are found outside of the coding region (4 432 885 in non-gene regions versus 1 412 731 in gene regions). A pan-cancer analysis found significantly mutated windows (292 to 3881 in count) demonstrating that there are significant numbers of large mutated regions in the non-coding genome. The 59 significantly mutated windows were found in all studied races and cancers. These offer 16 regions ripe for additional study within 12 different chromosomes—2, 4, 5, 7, 10, 11, 16, 18, 20, 21 and X. Many of these regions were found in centromeric locations. The X chromosome had the largest set of universal windows that cluster almost exclusively in Xq11.1—an area linked to chromosomal instability and oncogenesis. Large consecutive clusters (super windows) were found (19 to 114 in count) providing further evidence that large mutated regions in the genome are influencing cancer development. We show remarkable similarity in highly mutated non-coding regions across both cancer and race.
Spatial density of open chromatin: an effective metric for the functional characterization of topologically associated domains
Authors: Jiang Shuai , Li Hao , Hong Hao , Du Guifang , Huang Xin , Sun Yu , Wang Junting , Tao Huan , Xu Kang , Li Cheng , Chen Yang , Chen Hebing , Bo Xiaochen 
Published: August 2020

Abstract
Topologically associated domains (TADs) are spatial and functional units of metazoan chromatin structure. Interpretation of the interplay between regulatory factors and chromatin structure within TADs is crucial to understand the spatial and temporal regulation of gene expression. However, a computational metric for the sensitive characterization of TAD regulatory landscape is lacking. Here, we present the spatial density of open chromatin (SDOC) metric as a quantitative measurement of intra-TAD chromatin state and structure. SDOC sensitively reflects epigenetic properties and gene transcriptional activity in TADs. During mouse T-cell development, we found that TADs with decreased SDOC are enriched in repressed developmental genes, and the joint effect of SDOC-decreasing and TAD clustering corresponds to the highest level of gene repression. In addition, we revealed a pervasive preference for TADs with similar SDOC to interact with each other, which may reflect the principle of chromatin organization.