bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mechanical and physical properties of Mg alloys prepared by SPD methods
Authors: Lukáč P , Trojanová Z , Džugan J , Halmešová K 
Published: September 2021

Abstract
Magnesium alloys were prepared by severe plastic deformation (SPD). Three methods were used. The mechanical and thermal properties were estimated. The increase in strength could be attributed to the grain refinement and increased dislocation density. The thermal conductivity and expansivity was measured for samples prepared with different methods. Some examples are shown and discussed.
Investigation of the influence of calcination temperature on morphology and structure of electrospun 1D SnO2 nanostructures
Authors: Tański T , Smok W , Matysiak W 
Published: September 2021

Abstract
The aim of the study was to manufacture the SnO2 one-dimensional nanostructures via the sol-gel technique and electrospinning methods from a solution of polyvinylpyrrolidone (PVP), tin chloride pentahydrate (SnCl4-5H2O), N, N-dimethylformamide (DMF) and ethanol (EtOH). The as obtained fibrous mats consisting of polymer and precursors particles were subjected to the heat treatment in air in the following temperatures 500, 600 °C to obtain pristine tin oxide nanowires. The scanning electron microscope (SEM) was used to determine the effect of calcination temperature on the morphology and structure of produced 1D SnO2. The energy dispersive spectrometry (EDX) and Fourier-Transform Infrared spectroscopy (FTIR) were performed to investigate the chemical composition and structure of manufactured nanomaterials, respectively.
Effect of inclusions on the fatigue strength of a bearing steel
Authors: Nový F , Bokůvka O , Vicen M , Činčala M , Nikolić R 
Published: September 2021

Abstract
Here are presented results of experimental investigation about effect of inclusions on the fatigue strength of a bearing steel 100Cr6. Fatigue tests were carried out at sinusoidal cyclic tension-compression loading, f = 190 Hz, R = −1, room temperature, in the region ranged from N ≈ 3.5 × 105 to N ≈ 1.0 × 108 cycles of loading. Initiation of the fatigue cracks was observed in the bulk of the tested specimens and the so-called “fish eyes” were observed, mainly on the TiN inclusions (66 % Ti, 19 % N, 9 % Cr, remainder Fe, V, Zr). The TiN inclusions are hard, with sharp edges causing a significant stress concentration in a small localized area, resulting in an initiation of a fatigue crack. On the other hand, in standard for the chemical composition of this steel, the content of Ti was not prescribed.
A Thermodynamic Chamber Modelling Approach for Oil Free and Oil Injected Twin Screw Compressors
Authors: Ramchandran G , Harrison J 
Published: September 2021

Abstract
As computational modelling becomes an increasingly reliable and key component in accelerating the design process for twin screw machines, the goals for engineers now include developing faster running and physically accurate component models to optimize machine performance and efficiency, minimize internal leakage, reduce unwanted noise and pulsations, and properly size bearing supports in the machine. Accurately capturing these aspects via physical models helps in analyzing operating points that were not tested as well as in understanding how the machine will perform in a surrounding system. Thereafter, engineers can find an optimal design in a timely manner for the fastest speed to market as well as reduce physical testing to keep development costs low. This paper presents the use of a multi-physics modelling platform - GT-SUITE - in conjunction with SCORG – a well-established tool for the design and analysis of twin screw machines – to explore meeting the aforementioned goals. Two case studies are presented for a 3/5 oil free air compressor and a 4/5 oil injected air compressor. Comparisons to the mass flow rates of the gas and oil, temperatures, indicated power and the instantaneous chamber pressure vs rotation angle were made against test data available from the Centre for Compressor Technology at City University. The sensitivity of oil injection timing on the discharge temperature and power is shown and an optimum timing was found. The validated chamber models may be integrated into a system as well as used for further optimization to improve the original compressor performance.
Application of Path Homotopy in Twin Screw Compressor Rotor Profile Design
Authors: Patil Sumit , Stosic Nikola , Kovacevic Ahmed , Smith Ian , Asati Neeraj 
Published: September 2021

Abstract
This work explores application of an idea called ‘Path Homotopy’ from Topology in twin screw compressor rotor profile design. It is well known that twin screw rotor profiles impact the overall performance of screw compressors to a great extent. Almost all the well known profiles that are commercially used in twin screw compressors are generated out of analytical curves such as circles, lines and conic sections. Analytical representation has its own advantages in profile design but it limits the search space of all possible shapes that can be incorporated in profiles. This work aims at proposing an approach for rotor profiling that sticks to the analytical nature of curve representation in profiles while simultaneously extending the search space of curves that can be deployed in the design. Path homotopy has been identified as one of such approaches. Profile elements can be defined as homotopies between well known analytical curves (circles, lines and conic sections) and the homotopy parameter can directly influence these curves morphologically in their analytical form itself. In this way, shapes other than those used traditionally in profiling can be explored in search of the better rotor profiles.
Study on screw rotor thermal machining method of single screw compressor
Authors: Wang S Y , Wang Z L , Shi H W , Wang Z M , Hao M M , Wang J 
Published: September 2021

Abstract
Single screw compressor (SSC) is a type of rotary compressor with excellent performance. However, under high temperature conditions, the hot deformation of the screw rotor and the star wheel cause the change of the gap of the meshing pairs, which seriously degrades the compressor performance. In order to solve the problem of the gap variation of the meshing pairs, a new hot-state machining method is proposed to study the deformation characteristics of the screw rotor in the hot-state machining process, which provides some reference data for the pre-deformation of the rotor in the machining process. Numerical calculation model of thermal machining process for screw rotor was established by using finite element method. With the validated model, the deformation characteristics in the process of hot working were studied by changing the number of heating holes, diameter of heating holes and temperature of heating holes. Results show that screw rotor deformation will increase with the increase of heat source temperature and diameter, and the deformation distribution of the screw rotor is not significantly affected by the heat source temperature and diameter, but will be more uniform with the increase of heat source quantity. The research work in this paper can provide theoretical basis for hot machining of screw rotor for SSC.
Theoretical and Experimental Study on Rotary Compressor with Double Vapor Injection and Its System
Authors: Wei H J , Xu J , Yu B , Yang O X , He S G , Zhao H H , Hu Y P 
Published: September 2021

Abstract
This paper takes three kinds of double vapor injection compression cycle as the research object, that is, the two-stage compression cycle with double vapor injection on low-pressure cylinder and intermediate of two cylinders (Cycle A), the two-stage compression cycle with double vapor injection on high-pressure cylinder and intermediate of two cylinders (Cycle B), and the three-stage compression cycle with double vapor injection (Cycle C). According to the law of conservation of mass and energy, the thermodynamic analysis model of each cycle was established, and the influence of saturation temperature of double vapor injection on the performance of each cycle was analyzed. The theoretical analysis results indicated that the refrigeration capacity of cycle A, cycle B and cycle C increase by 12.5%, 3.5% and 4.6%, respectively, and COP of that increase by 3.09%, 2.23% and 3.22%, respectively, compared with that of single stage compression cycle. Based on cycle A, a single-machine two-stage rotary compressor with double vapor injection and its heat pump air conditioning are made. The experimental results showed that, the heating capacity of cycle A can increase by 14.6% when the heating COP is equivalent, and the heating COP can increase by 4.4% when the heating capacity is equivalent, compared with the two-stage compression cycle with single vapor injection, under the –15°C ambient temperature heating condition.
Current limits of CO2 compressors working in integrated mechanical subcooling cycles
Authors: Nebot-Andrés Laura , Sánchez Daniel , Cabello Ramón , Calleja-Anta Daniel , Fossi Carlos , Llopis Rodrigo 
Published: September 2021

Abstract
CO2 systems used in refrigeration are becoming more complex with the aim of improving their energy performance. The integrated mechanical subcooling system is being studied to enhance the COP and the cooling capacity of the plants as one of the possible solutions for hot climates in the last years.
Last studies determined their optimum working conditions where the COP is maximum. However, the compressor of the integrated mechanical subcooling cycle works out of the range of operation in some cases. This work presents the main technical limitations of this compressor in an experimental plant.
The main objective is to determine what these limits are and to highlight the need to develop new compressors for these applications. Improving the operation of these compressors will further increase the energy performance of the overall system.
Increasing Boiling Fluid Flowing Efficiency from Motive Nozzles of Two-Phase Ejectors
Authors: Sharapov Serhii , Chekh Oleh , Husiev Danylo , Klymenko Volodymyr , Shaparenko Oleksiy 
Published: September 2021

Abstract
The article contains the possibility of increasing boiling fluid flowing efficiency from expanding channels. This process takes place in the motive flow nozzle of a liquid-vapor ejector, working on the principle of thermal stream compression. Efficiency increasing by profiling the diffuser part of the nozzle. Modern industry uses nozzles, which are like de Laval nozzles, with straight walls of the diffusers. The authors suggest paying closer attention to profiling these nozzles, which might increase their efficiency and improve their gas-dynamic characteristics. For comparison, we choose a channel of a traditional form (with straight walls of the diffuser) and a channel of parabolic shape. The article contains a mathematical model to calculate the process of flowing the boiling fluid from the authors-designed channels – the peculiarities of this model that appear after changing the geometry of its streaming part. We obtain comparative analysis calculation results based on the mathematical model and the Ansys CFX workflow model. As a result of numerical calculation using the authors mathematical model and modelling in the Ansys CFX software package, it concludes that the parabolic shape of the diffuser is the most favourable. In the boiling process, the liquid central core is boiling at the optimum distance from the nozzle throat, and the flow of a stable vapor structure with the required pressure value for each regime forming at the outlet.
Photo- and magnetic-field-induced conductivity change in the BiFe1-xCoxO3 films
Authors: Kretinin V V , Begisheva O B , Zelenov F V , Mashkov P P , Pavlova A N 
Published: September 2021

Abstract
The magnetic and electrical properties of the polycrystalline BiFe1-xCoxO3 films have been investigated in the temperature range of 80–600 K and magnetic fields of up to 12 kOe. The photocurrent and the diode effect induced by the blue light laser illumination at room temperatures have been established. The ohmic conductivity has been determined from the I–V characteristics and the conductivity growth in a magnetic field has been observed. The deviation of the temperature dependence of the magnetization from the power law below room temperature has been found.
Research of physical and mechanical properties of plywood based on thermally modified veneer
Authors: Krivorotova A I , Orlov A A , Korchuk Yu A , Popov A A 
Published: September 2021

Abstract
The article presents the results of a study of the physical and mechanical properties of plywood based on thermally modified birch veneer. The implementation of a full-factor experiment in the temperature range from 160 to 200 °C with a duration of 120 to 240 min made it possible to establish the nature of the dependence of the change in strength in static bending and strength in shearing along the adhesive layer on the veneer heat treatment mode. The parameters of veneer heat treatment are determined, which do not lead to a decrease in the strength of plywood, but allow to reduce the indicators of water absorption and swelling by an amount from 20.4 to 33.5%. Plywood based on thermally modified veneer acquires higher strength and water resistance, which significantly expands the scope of application of glued wood based on urea-formaldehyde resins.
Carbon-containing materials for high-temperature friction units
Authors: Roshchin M N , Lukyanov A I , Krivosheev A Yu 
Published: September 2021

Abstract
The paper considers frictional interaction of carbon-containing composites with steel at high temperatures. Material “Hardcarb-TPG” has better tribological characteristics than materials “Hardcarb” and “Hardcarb-TP”. At a speed of 0.16 m/s and a load of 1.0 MPa, the friction coefficient of the Hardcarb-TPG material is 23% lower than that of the Hardcarb-TP material. Thus, at a temperature of 500 °C and a load of 1.0 MPa, the friction coefficient of the Hardcarb-TPG material at a speed of 0.16 and 0.25 m/s is 8 and 14% higher than at a speed of 0.05 m/s, respectively. The friction coefficient of the Hardcarb-TPG material at a speed of 0.16 m/s and a load of 1.0 MPa in the temperature range 300…600 °C varies from 0.13 to 0.30.
Physicochemical regularities in highly filled polyaluminosilicate applied on aluminum base by 3D aerosol printing
Authors: Ivanov A A , Chermoshentseva A S 
Published: September 2021

Abstract
A modified technique has been used to synthesize a highly filled polyaluminosilicate with a controlled supramolecular structure during its applying on an aluminium base by 3D aerosol printing. It has been found how the pH medium affects the polyaluminosilicate ability to form fractal supramolecular formations. Methods to control the highly filled polyaluminosilicate structure directly along the aluminium base surface have been found.
Modeling of the stress-deformed state of a capacitive apparatus with geometric deviations when mounting on a foundation
Authors: Rubtsov A V , Arkhipova K S , Kulakov P A , Afanasenko V G , Zubkova O E , Mukhametzyanov Z R 
Published: September 2021

Abstract
The reliable and trouble-free operation of the capacitive equipment of hazardous production facilities is significantly influenced by the quality of the installation performed before commissioning. So, during the installation of capacitive equipment, various geometric inconsistencies and deviations may occur, which are established by the current regulatory and technical documents for the installation of technological equipment. If unacceptable deviations and inconsistencies established by regulatory and technical documents are found, they must be fully eliminated. However, in certain cases, the regulatory and technical documentation allows operation with various insignificant geometric deviations and inconsistencies that do not go beyond the established limits. This may relate to deviations from the design horizontal position of the apparatus when installed on a foundation. It should be noted that during operation, under the influence of increased pressure, temperature and other loads, an apparatus with deviations of this type can undergo a completely different stress-deformed state compared to an apparatus without geometric deviations, which is not taken into account in expert diagnostics, strength analysis and assessment of residual resource. The solution to this issue can be approached using software systems that allow building 3D models of the objects under consideration with the introduction of all the necessary parameters into these models and getting a real picture of the distribution of zones of increased stress. In this work, the stress-deformed state of the process vessel is simulated due to the impact of working loads and different directions of deviation from the horizontal design position of the body when the apparatus is mounted on the foundation.
Electromechanical stand for the process of throwing soil with a cutter-thrower
Authors: Gnusov M A , Drapalyuk M V , Druchinin D Yu , Bukhtoyarov L D 
Published: September 2021

Abstract
Every year in all countries of the world there are natural disasters, including forest fires. Quality wood is lost. Today the problem is dealt with both by research teams and production companies. The article presents one of the methods for studying the throwing process and adjusting the adequacy of simulation models. The creation of an electromechanical stand for the process of throwing loose elements allows you to monitor the process of separating portions of soil from the main layer, as well as track and digitize movements in molasses with various characteristics of the entire system under study.
Machine-building organization production using quality management methods
Authors: Priimak E V , Razina I S 
Published: September 2021

Abstract
Mechanical engineering is the leading industry in the world, which has a significant impact on the level of development of a country. It produces various machines, machine tools, mechanisms, devices. The machine-building sector provides equipment to all other sectors of the economy, so the results of the work of related areas depend on its level of development and product quality. Among the main problems of the sector in Russia are high depreciation of fixed assets and low level of innovation. As a result, the low competitiveness of domestic machine-building products in the world market. Competitive advantages can be achieved primarily by improving the quality of manufactured products. Prompt solution of problems related to product quality is achieved by implementing various methods aimed at preventing the appearance of defects. The study presents an algorithm for the development and implementation of the 8D methodology in order to prevent the recurrence of product defects at the enterprise of Aktanyshsky Aggregate Plant. With the help of simple tools that underlie the 8D methodology, the causes of the defect were identified and corrective and preventive measures were proposed.
Analysis of the stress-deformed state of a tube bundle at different values of partition thicknesses and their deviations from verticality
Authors: Zakirnichnaya M M , Rubtsov A V , Kulakov P A , Galiullina N 
Published: September 2021

Abstract
Shell and tube heat exchangers of hazardous industrial facilities are used to heat or cool working media and represent a rather complex individual design, which can consist of several structural elements, such as a body, bonnets, heat exchange tubes, tube sheets, partitions, etc. The failure of one element contributes to the failure of the entire heat exchanger. In the process of assembling or installing elements of the heat exchanger, the formation of various geometric deviations from design solutions is possible, which may be associated with violations of the technology of the assembly process, installation, etc. The presence of such deviations can negatively affect the reliable and trouble-free operation of the apparatus, serve as a scenario for the formation of places of increased stresses, leading to the initiation of defects in these zones and premature failure. One such deviation may be a change in thickness values and deviations from the vertical design of the transverse baffles of the tube bundle as supports for the heat exchange tubes. In the existing methods, the transverse partitions of the tube bundle do not pay attention and do not take into account their possible impact upon deflection on the stress-deformed state of the apparatus as a whole. In this work, the relationship of the effect of thicknesses, values and directions of deviation from the vertical location according to the design of transverse partitions of the pipe bundle on maximum equivalent stresses is investigated.
Dubrovin’s method and Ablowitz-Kaup-Newell-Segur hierarchy
Authors: Smirnov A O , Kolesnikov A S 
Published: September 2021

Abstract
Previously, the Dubrovin method was used to construct spectral curves of multiphase solutions of such integrable models of nonlinear optics as vector and derived nonlinear Schrödinger equations. The method of constructing spectral curves of multiphase solutions of the scalar nonlinear Schrödinger equation was based on replacing matrix differential operator from the Lax pair by the scalar one. The present paper shows that Dubrovin’s method gives the same results. At the same time, it has the advantage that it consists in a simpler construction of multiphase solutions expressed in terms of elementary functions.
Urinary sediment CCL5 messenger RNA as a potential prognostic biomarker of diabetic nephropathy
Authors: Feng Song-Tao , Yang Yang , Yang Jin-Fei , Gao Yue-Ming , Cao Jing-Yuan , Li Zuo-Lin , Tang Tao-Tao , Lv Lin-Li , Wang Bin , Wen Yi , Sun Lin , Xing Guo-Lan , Liu Bi-Cheng 
Published: September 2021

ABSTRACT

Background
Urinary sediment messenger RNAs (mRNAs) have been shown as novel biomarkers of kidney disease. We aimed to identify targeted urinary mRNAs in diabetic nephropathy (DN) based on bioinformatics analysis and clinical validation.

Methods
Microarray studies of DN were searched in the GEO database and Nephroseq platform. Gene modules negatively correlated with estimated glomerular filtration rate (eGFR) were identified by informatics methods. Hub genes were screened within the selected modules. In validation cohorts, a quantitative polymerase chain reaction assay was used to compare the expression levels of candidate mRNAs. Patients with renal biopsy–confirmed DN were then followed up for a median time of 21 months. End-stage renal disease (ESRD) was defined as the primary endpoint. Multivariate Cox proportional hazards regression was developed to evaluate the prognostic values of candidate mRNAs.

Results
Bioinformatics analysis revealed four chemokines (CCL5, CXCL1, CXLC6 and CXCL12) as candidate mRNAs negatively correlated with eGFR, of which CCL5 and CXCL1 mRNA levels were upregulated in the urinary sediment of patients with DN. In addition, urinary sediment mRNA of CXCL1 was negatively correlated with eGFR (r = −0.2275, P = 0.0301) and CCL5 level was negatively correlated with eGFR (r = −0.4388, P &lt; 0.0001) and positively correlated with urinary albumin:creatinine ratio (r = 0.2693, P = 0.0098); also, CCL5 and CXCL1 were upregulated in patients with severe renal interstitial fibrosis. Urinary sediment CCL5 mRNA was an independent predictor of ESRD [hazard ratio 1.350 (95% confidence interval 1.045–1.745)].

Conclusions
Urinary sediment CCL5 and CXCL1 mRNAs were upregulated in DN patients and associated with a decline in renal function and degree of renal interstitial fibrosis. Urinary sediment CCL5 mRNA could be used as a potential prognostic biomarker of DN.