bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mathematical model of the condensation process in the crankcase space of a piston engine warmed up under negative temperatures of a cold climate
Authors: Kaminsky V N , Kostyukov A V , Kolunin A V , Materi I V 
Published: May 2021

Abstract
In recent years, there has been a trend of increasing activities in the development of polar territories. Negative temperatures are a characteristic feature of the North. Negative temperatures have a negative impact on the state of power installations of land, air and water transport, mobile, stationary power plants and small-scale mechanization facilities. The engine is least adapted unit for operation in such conditions. There is a chain of negative factors that consistently provides a connection between the state of the lubrication systems and the negative temperatures, in which the equipment is operated. Condensation processes are a primary link in this chain. The existence of condensation processes in the crankcase space when a piston engine is warmed up at negative temperatures is experimentally proved. The percentage of engine oil watering and the dew point temperature of crankcase gases are determined in the conditions of a full-scale experiment. However, the high labor intensity and significant financial costs of organizing such experiments require the search for other methods of testing. A mathematical representation of reality, which allows you to obtain objective and adequate experimental data information, can be one of the ways to solve this problem.
The use of light fractional composition fuels in the electric flame jet of a diesel engine
Authors: Kaminsky V N , Kostyukov A V , Kolunin A V , Materi I V 
Published: May 2021

Abstract
In recent years, there has been an increased interest in the development of the polar territories of our planet. A large number of minerals on land and in the shelves attracts the attention of our contemporaries. Development of these territories with a harsh climate is possible by using modern vehicles and mechanisms that ensure the exploration of sediment layers, extraction of deposits, transportation of rocks and raw materials. The most common mode of transportation in these conditions are motorized vehicles. One of the most important aspects in the operation of automotive equipment in conditions of temperatures below freezing point in a cold climate is the startup of the diesel engine after a long period of parking. The industry produces auxiliary equipment. In this regard, heat generators are widely used. There are individual and group heaters of various types, including flame and infrared heaters that can provide support in the pre-starting procedure. In addition, there are means to facilitate the start-up. The reliable start of a diesel engine is influenced by factors such as the temperature of the air charge, the operating torque of the crankshaft, the conditions of fuel spraying, the activity of heat exchange processes and the tightness of the mating of the cylinder-piston group parts. The use of fuels of light fractional composition with an electric flame jet or the so-called gas-electric flame jet can constitute an effective solution to the problem.
Investigation of the combined process of isothermal crimping with a set of thickenings at the ends of pipe blanks
Authors: Pasynkov A A , Larin S N , Gurova O Yu 
Published: May 2021

Abstract
The article discusses the production of cylindrical hollow workpieces with different cross-sections along the height. The difference in cross-sections is ensured by crimping. During the crimping, the ends of the blanks are thickening. The operation under consideration is carried out in a hot state with local heating of the workpiece elements with a slow movement of the tool. It occurs due to the material grade of the workpiece, which is very demanding in terms of the deformation conditions. Simulation of the studied combined process has been carried out, during which the influence of the parameters of the main operations (deformation rate, heating parameters, friction) on the possibility of obtaining products with specified geometric characteristics has been established.
Study of the machining quality of CMC ceramic composite during high-speed grinding
Authors: Rechenko D S , Kamenov R U 
Published: May 2021

Abstract
Ceramic matrix composites (CMC) are now an increasingly popular choice of materials used to manufacture critical parts for a variety of engineering applications. Due to the complex heterogeneous structure of CMC and the high hardness of at least one of the components (fiber or matrix)-processing such materials becomes an extremely difficult task. In addition, the heterogeneous structure and brittleness of CMC leads to different material removal mechanisms during machining, resulting in unique surface defects that reduce the quality of the machined surface. This article deals with the issues of ensuring the quality of the machined surface of samples made of SiC/SiC ceramic composite with ceramic matrix, by selecting the characteristics of the grinding tool and cutting modes during high-speed grinding.
Development of polymer composite materials and structures with their subsequent utilization after the mission
Authors: Trushlyakov V I , Russkikh G S , Blesman A I , Davydovich D Yu , Iordan Yu V , Fateev P D 
Published: May 2021

Abstract
The article considers the transfer of utilization technologies for detachable elements of the launch vehicle (LV) structures during the launch at the powered phase after their detachment at the unpowered phase of the descent trajectory to the utilization of tanks for fuel and lubrication materials (FLM) delivered to outlying regions of the Arctic. Opposed to detachable LV structures, utilization of FLM tanks is carried out under ground conditions by burning fuel elements prepared from FLM tank structures in conventional boilers and domestic heating furnaces. The research task has been set considering the possibility of implementing the requirements in the design and construction of polymeric composite material (PCM) to manufacture combustible tanks for the FLM storage. The requirements have been formulated for the production stages of combustible PCM and utilization system including the definition of design and construction parameters of PCM. The results of preliminary experimental studies in terms of determining the combustibility of the proposed PCM and their strength characteristics have shown the possibility of developing combustible structures.
New way to increase the profitability of railway transportation of viscous petroleum products at low air temperatures
Authors: Vorobiev A A , Moiseev V I , Samarkina I K , Komarova T A , Krutko A A , Sedykh D A , Fedorov I V , Ksenofontova V A 
Published: May 2021

Abstract
The article deals with the main problems associated with the transportation and unloading of viscous petroleum products by rail at low temperatures. Taking into account the analysis of the applied technologies and modeling of the ongoing processes in the ANSYS program, a solution to the problems that arise is proposed by using a tank car with a steam-heating casing or by applying thermal insulation to the upper part of the tank. To ensure the tightness of the drain device of the tank car and to avoid the occurrence of environmental disasters, the modernization of its design is proposed.
Influence of technological regimes of plasma chemical deposition on texture formation in aluminum nitride films
Authors: Baranova L V , Strunin V I 
Published: May 2021

Abstract
Textured polycrystalline aluminum nitride films were grown by magnetron sputtering of an aluminum target in a mixture of argon and nitrogen, followed by the formation of a film on sitall substrates. The influence of the pressure of the working gases, the power dissipated on the target, and the ratio of the Ar / N2 gas fluxes on the texture of the aluminum nitride films are investigated. The phase composition and degree of crystallinity of the obtained films were determined using scanning electron microscopy and X-ray diffraction. The results of studies of the phase composition and parameters of the crystal structure of aluminum nitride films are presented: the size of the coherent scattering regions, the predominant orientation of the crystallites in the growing film, and the degree of crystallinity. It is noted that the films are predominantly oriented along the (111) and (002) planes. The degree of crystallinity of the A1N films varied from 10 to 30% depending on the conditions of the deposition process. The relative microdeformation of the lattice (Δd/d), depending on the parameters, ranged from 1.7·10−3 to 6.9·10−3. The size of the crystallites is affected by the microdeformation of the lattice, with its increase by 4 times, the size of the crystallites decreased by 3.6 times from 29 to 8 nm.
The features of organic soil dielectric characteristics in the Arctic region
Authors: Suslov K N , Yashchenko A S 
Published: May 2021

Abstract
The results of measurements of the complex dielectric permittivity of the Arctic region organic soil are presented. The trends in the change of the soil CDP with varying soil moisture and temperature are described. We compared measure data with the values calculated by the Dobson model for sandy and silty clay soil. It was found that the experimental and model data differ markedly.
On physical reliability of constitutive relations in plasticity for plane processes with bend point
Authors: Abirov R A 
Published: May 2021

Abstract
We focus our attention on the physical reliability of plasticity at complex loading. It is important for reliable solution of boundary-value problems. The results of experiments on complex loading in the form of trajectory in the form of two-element trajectories for weakly hardened material are considered in this issue. An analysis of physical reliability of the simplest versions of plasticity theories for describing active processes of complex loading with bend point is given here. We provide analysis and recommendations as to preferable applications of classical theories for plane complex loading modes. It is shown that neglecting the loading process geometry lead to considerable errors in theoretical calculations.
Numerical calculation of the natural vibration frequencies of thermo-elastic rods taking into account the effect of the temperature gradient
Authors: Kikvidze O G , Sakhvadzeand G G , Sakhvadze G Zh 
Published: May 2021

Abstract
Elastic rod elements are considered, the axial line of which in the natural state is a flat curve and remains a flat curve after loading. The following assumptions are used: the normal cross-sections, which are flat before deformation, remain flat and normal to the deformed thermo-elastic axial line after deformation; the temperature field is stationary and non-uniform. Nonlinear equations of motion of the rod are obtained, taking into account the rotational inertia of cross-section and the extensibility of the axial line.
Optimization of the rubber element of the rubber-metal hinge of a tracked system
Authors: Korostelev S A , Korostelev D S 
Published: May 2021

Abstract
The paper presents the formulation of the problem of optimal design of rubber bush of the track link and its solution. The search for the optimal design is based on the results of calculating the stress-strain state of the rubber ring caused by the assembly of the rubber-metal hinge and loads during subsequent operation. As an objective function, the specific energy of deformation of the rubber was chosen. The dimensions of the rubber ring of the rubber-metal hinges in the undeformed state are taken as variable parameters. Formulation of the optimization problem imposes constraints on the design parameters in the form of inequations. The solution of the problem of optimal design and the results of durability tests are presented.
Effects of slag on cement hydration by electrical resistivity characterization
Authors: Xiao Chengyi , Lv Quanhong , Jiang Xingjiao , Xiao Lianzhen 
Published: May 2021

Abstract
Non-contact resistivity measurement was used to characterize the early hydration characteristics of cement paste with different contents of slag, combined with other traditional methods such as hydration heat, compressive strength. The results show that the maximum compressive strength of sample P0.4SL20 was 34.4 MPa and 45.2 MPa at 3 d and 7 d, respectively. The addition of slag could reduce the hydration heat of slurry, which makes the second hydration exothermic peak shift to the left. The characteristic points on electrical resistivity differential curve with different slag contents had good correspondence with the corresponding characteristic points on hydration heat release curve of samples with different slag contents. A good linear relationship between electrical resistivity and compressive strength was shown as f
c(3d) = 5.23992P(3d)-12.31066. The electrical resistivity method can be used to characterize the influence of slag on the hydration process of cement paste and predict its compressive strength.
The concrete application of lightning protection technology of electrical automation system in water conservancy and hydropower project
Authors: ZhaoChunLei  
Published: May 2021

Abstract
the development of science and technology has promoted the continuous progress of water conservancy and hydropower projects. Advanced equipment and advanced technology are widely used in water conservancy and hydropower projects, which improves the working efficiency and working level of staff in two directions, and also brings great economic benefits to the water conservancy and hydropower projects. Among them, electrical automation technology is widely used in water conservancy and hydropower projects as the basis of quality guarantee, therefore, correspondent research on it should be strengthened. The application of lightning protection technology in electrical automation system of water conservancy project is to provide guarantee for the stable operation of the electrical automation system of water conservancy project. This paper analyzes the lightning protection technology of electrical automation system used in water conservancy project from the practical point of view, and analyzes the main points of application of electrical automation in water conservancy and hydropower projects in detail.
Analysis of connection structure of prefabricated reinforced concrete exterior wall panels
Authors: Jian Tang , zhaofeng Zheng , minsi Chen , huihui Hu , yaru Sun 
Published: May 2021

Abstract
By analyzing and discussing the connection structure related to the fabricated reinforced concrete external wall panel, including the material, technology, connection principle and form method of the external wall panel, the design principles of the fabricated reinforced concrete external wall panel connection structure are summarized.
Research on the method based on the combination of BETC and BIM
Authors: Zhiqiang Chen 
Published: May 2021

Abstract
The virtual simulation model building (BIM) of civil engineering is used more and more widely. Based on the platform of “cost workshop” of civil engineering and the BETC method of “BIM virtual construction + actual engineering information + industry standard comparison”, this paper emphasizes the integration of “virtual construction technology”, “information pricing technology” and “industry standard requirements” of civil engineering. This method is conducive to the research of civil engineering BIM Technology and the development of cost information.
Research on BIM Technology in Smart City
Authors: Wu Bei , Chang Runwu , Zhang Jiamin , Sun Haowei , Luan Wenjie , Li Nan 
Published: May 2021

Abstract
With the vigorous development of green and intelligent concepts and technologies in China’s urban construction, BIM can no longer meet the tasks of data processing and management of a large number of information flows in green ecological urban areas. CIM (Urban Information Model), as an information means, has gradually become the engine power of future urban construction. Through the application of information technology and communication technology, smart cities can collect, analyze and integrate the key information of the core system of urban operation, and then make intelligent response to the needs of people’s livelihood, environmental protection, public safety and urban services, create a better life and promote the harmonious and sustainable development of cities. CIM refines the granularity of data to an electromechanical accessory and a door inside a single building in a city, and upgrades the traditional static digital city into a digital twin city with perceptibility, dynamic online and virtual-real interaction, providing a data foundation for agile management and fine governance of the city.
Modeling of Wake Effects in Steady State Mixing Plane Simulations of a High Lift Turbine Cascade with Different Combinations of Wake Passing Frequency and Wake Orientation
Authors: Führing A. , Kožulović D. , Bode C. , Franke M. 
Published: May 2021

Abstract
Due to operation at low Reynolds numbers, low pressure turbines of aircraft engines mostly show large laminar boundary layers and transitional separation bubbles which considerably change their viscous losses when interacting with impinging wakes. The change of loss depends on several wake parameters, among others on wake passing frequency and wake orientation. In the present work, these parameters are expressed in terms of Strouhal number and flow coefficient and their influence is investigated by means of unsteady Reynolds-averaged Navier-Stokes (RANS) simulations. Different combinations of both wake parameters which are typical of aircraft engine conditions, are prescribed upstream of a high lift turbine cascade, while the Reynolds number and Mach number are kept constant. The solver TRACE by DLR and MTU Aero Engines together with the γ −
Re
Θ transition model by Langtry and Menter has been used. Further, the wake profile is representative for upstream turbine profiles and is prescribed by a correlation framework which has been calibrated in previous work. A newly developed quasi-unsteady wake model (QUWM) is applied in order to model the effects of periodically passing wakes in steady state simulations involving mixing plane interfaces. It is shown that the gap between unsteady and steady state simulations is narrowed significantly by the QUWM while still maintaining quick turnaround times that are crucial in industrial flow solver applications.
Sweep-angle effect on low-order acoustic prediction for low-speed fans
Authors: Zarri Alessandro , Christophe Julien , Moreau Stéphane , Schram Christophe 
Published: May 2021

Abstract
The low-speed fans that are used for automotive engine cooling contribute to a significant part of the global noise emitted by the vehicle. Automotive engine cooling manufacturers are therefore interested in developing low-order noise prediction methodologies that include the radiated sound in pre-design optimization cycles. Two among the most influential broadband noise mechanisms characterizing the automotive axial cooling-fans spectra in operating conditions are the turbulence-impingement noise and the trailing-edge noise. We modelled them through the application of a semi-analytical method called Amiet’s airfoil theory, appropriately adapted via a strip-theory approach, in order to take the rotating motion into account. In modern fan designs, the fan blades are strongly forward-swept, meaning that the blade edges are not always perpendicular to the tangential-to-rotation velocity vector. This is particularly true at the tip of the blades where the sweep angle often reaches its maximum value, and where most of the noise is expected. Sweep was shown to reduce the noise emitted by isolated airfoils, but its effect on rotating machines is not yet well understood. Its prediction requires an extension to the classical Amiet’s theory, which has been implemented in this work, permitting to assess the importance of varying sweep on the acoustic far-field radiation. Amiet’s theory is therefore applied for the two noise mechanisms mentioned above, starting from steady CFD simulations, reproducing the ventilator geometry operating at its maximum-efficiency condition. In contrast with the classical unswept formulation, the predicted results considering the sweep variation along the blade span better compare with the experimental measured ones in the VKI anechoic chamber, especially for high frequencies.
Cavitation analysis of a Delft twisted hydrofoil using multi-process cavitation model
Authors: Miki Takahito , Fujiyama Keita , Tsuda Shin-Ichi , Irie Tomohiro 
Published: May 2021

Abstract
Cavitation is essentially formed of a combination of multiple processes. Most of the conventional cavitation models consider these in a single model, and the conservation equation for void fraction of cavitation bubbles is solved. To understand the relationship between cavitation and turbomachinery performance, not only void fraction, but also states of cavitation bubbles such as number and radius may become useful data. The multi-process cavitation model proposed by Tsuda and Watanabe is one of the solutions. This model has been implemented into commercial CFD software scFLOW. To validate the implemented cavitation model, cavitation around a Delft twisted hydrofoil was analyzed, and the result was compared with past studies. From a parametric study of the bubble growth coefficient in this cavitation model, it was found that 0.2 for expansion and 0.05 – 0.1 for shrinkage are appropriate. Cavitation shedding frequency and cavity volume agreed well with the past studies by using those coefficients. Since the multi-process cavitation model provides detailed cavitation bubble states, a new index is proposed to detect bubbly regions and its distribution compares well with experimental data. This implies that the multi-process cavitation model will help us to predict cavitation noise and erosion risk as well as to understand the mechanism of the cavitation phenomenon.
Numerical investigation of the effect of leakage flow on cavitation in centrifugal pump
Authors: Moganaradjou Yashwant , Phukan Anindita Apurbaa , Vengadesan S , Chatterjee Dhiman 
Published: May 2021

Abstract
Numerical studies on pumps emphasize mainly on modelling the interactions between the impeller and the volute to obtain an accurate understanding of the physics involved. However, the importance of modelling leakage paths, which is known to have a significant influence on the flow structure in the pump, necessitates an in-depth analysis. This activity is undertaken in this paper by investigating a specific case of a centrifugal pump. Numerical studies have been conducted on the pump modelled with and without leakages for the design condition. The sliding mesh method is used to obtain single phase pressure pulsations data at some important locations in the volute and the leakage path, and transient Multiple Reference Frame (MRF) modelling is utilized to conduct the cavitation analysis. It is observed that for the case under study, the pressure pulsations pattern and the cavitation behaviour varies significantly due to the inclusion of leakage paths in the analysis.