bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of the effect of a dent on the stress state of the wheel in the “wheel-rail” contact
Authors: Vorobiev A A , Krutko A A , Sedykh D A
Published: February 2021

The Purpose of this work is to determine the effect of a dent on the stress state of the wheel at different rim thicknesses. The article uses methods of numerical solution of partial differential equations (finite element method) to determine the stress state in the contact “wheel-rail” at different thickness of the rim with a chink and without a chink. Based on the research, proposals have been developed to change the norms of rejection of wheels with a thin rim in the presence of a dent on the surface of the ride. Changing the norms of rejection of wheels with a thin rim in the presence of a dent on the surface of the ride will increase the resource of the wheels and thereby reduce the need for new wheels.
Mass-centering characteristics of solids within quasi-rotation surfaces
Authors: Beglov I A
Published: February 2021

The methods for generation of digital 3D-models of solids within one sheet of a quadrilateral surface of quasi-rotation are described. The resulting models are used to create solids by means of 3D-printing. When analysing the physical properties of solids, an assumption is made about the specificity of the location of their centres of mass. To verify this assumption, the capabilities of the automatic projection are applied. Based on the results obtained, it is found that there is a certain solid - an individual case of the studied solids, the centre of mass of which is located in the geometric centre of its outline, which is a circle. The error curve method is applied to determine the initial parameters of modeling the desired object. As a result of the search, a digital and solid-state model of a solid within a single sheet of the quasi-rotation surface, whose center of mass coincides with the geometric center of its outline, are obtained. The produced solid has properties that partially coincide with the properties of rotation solids. Such a coincidence is not obvious. In general, the center of mass of the studied solids is not located at the indicated point.
ABAC Implementation Based on Key Pre-Distribution Scheme
Authors: Belim S V , Belim S Yu
Published: February 2021

In the article, the KDP key pre-distribution scheme is modified for attribute access control. A scheme for implementing attribute-based access control on symmetric encryption is proposed. There are three participants in the scheme: a key distribution server, a subject, and a storage server. The key distribution server sends key content over secure channels when the system is initialized. The key materials content is determined by the attributes of the object and the subject. The storage server calculates the object ′s encryption key based on the object ′s key materials and attributes. The object is stored encrypted. If the subject has the necessary attributes, it can calculate the encryption key and access to object. If the subject does not have a sufficient set of attributes, the key cannot be computed and access is denied.
Improvement of devices for early diagnostics of the optical fibers state of telecommunications systems
Authors: Bogachkov I V , Gorlov N I
Published: February 2021

A construction of the Brillouin reflectometers schemes is discusses in this work. The algorithms for processing measurement results are consider.

The results presented in the researches allow us to improve the algorithms for processing Brillouin reflectograms by introducing reference channels and a reference database.

The presented schemes of Brillouin reflectometers are of interest for improving optical fiber monitoring systems.
Method of High-Noise-Resistant Qudrature-Pulse Phase Modulation
Authors: Khazan V L
Published: February 2021

The paper refers to the method of quadrature intra-pulse phase modulation (QIPPM). This method focuses on solving the relevant problem of improving the noise resistance of message transmission over communication channels with variable parameters. The problem is resolved by intra-pulse phase manipulation of signal quadratures by mutually orthogonal binary sequences of the Walsh function type. The advantage of the QIPPM modem over other modems is shown, and recommendations for its practical use in communication channels with pseudo-random tuning of operating frequency are given.
Research on improving the performance of telecommunication broadcasting and warning systems from the type of microprocessor platforms
Authors: Kolpakov A A , Belov A A , Kropotov Y A
Published: February 2021

The article discusses the use of various microprocessor platforms for the development of terminal devices of telecommunication broadcasting and warning systems. Their characteristics are investigated and the performance of the selected platforms is tested when mixing audio streams. The possibility of using parallel audio processing algorithms is also being considered.
Geometric Modeling IN THE Problems OF Lever Mechanism Kinematics Research
Authors: Lyashkov A A , Sheveleva T A
Published: February 2021

General information about the elements of lever mechanisms consisting of kinematic pairs is presented. The classification features of pairs are given: constraining conditions imposed by this pair, their graphic images, as well as brief descriptions of some of them. Two main problems of kinematics are highlighted. There are two main methods for solving the first problem of kinematics related to the solution of mechanism positioning questions: analytical and numerical. The second problem is an inverse one. A variety of methods for solving it is shown in the paper. The choice or development of the method is mainly determined by the complexity of the mechanism. The analysis of the documentary flow on the problem of kinematics of lever mechanisms allowed us to identify the main areas of research in this area. One of the promising areas is geometric computer modeling, which has a number of advantages in comparison with others. Its application makes it possible to study not only coordinate spaces formed by geometric elements of the lever mechanisms themselves, but also objects generated by products involved in these mechanisms functioning. The line of such research allows us to improve directly CAD systems used in modeling and obtain new results in various application areas, which is an urgent task.
Constructing paths to avoid multiple obstacles
Authors: Nefedov Y Y
Published: February 2021

This article deals with the issues of modeling the trajectory of an object moving on a plane. Its trajectory may intersect with obstacles (circles). The author proposes an algorithm for modifying the initial trajectory of the object taking into account the movement of obstacles. At the beginning, we describe how to divide the initial trajectory into sections. Then we describe how to modify the line on each segment in two cases, depending on the angle between the projection direction and the direction of movement of the obstacle center.
On smoothness of connection of spatial curve cyclographic projection segments
Authors: Panchuk K L , Lyubchinov E V
Published: February 2021

The correlation between smoothness of connection of segments of a spatial curve and the respective cyclographic projection is considered. The sufficient condition for smoothness

C
α

k
−
1

at the point of connection of segments of cyclographic projection of a spatial curve described by a polynomial spline of order k +1 is formulated and verified. It has been demonstrated that despite the derivative of order k +1 of the spline function describing the spatial composite curve along with all the higher-order derivatives not being continuous, it is possible to connect segments of the cyclographic projection with smoothness

C
α
r

, where r = k + i, i = 0,1,2,…. Achieving smoothness

C
α

k
−
1

,

C
α
r

through the formulated condition of sufficiency is demonstrated on numeric examples. The obtained results of the study can serve as the basis of development of effective algorithms of cyclographic formation of geometric objects applied in geometric optics, road surface form design, and optimal cutting tool trajectory design in pocket machining.
Using weight values of generalized velocities to handle deadlocks in the synthesis of anthropomorphic robot arm movement
Authors: Pritykin F N , Nebritov V I
Published: February 2021

When controlling the movement of an anthropomorphic robot arm mechanism in an organized space with forbidden regions, there is a possibility of deadlocks. The paper studies the motion synthesis using weight coefficients of generalized velocities in order to prevent deadlocks. As a result an algorithm for the motion synthesis using weight coefficients in the virtual simulation of the anthropomorphic robot arm movements is developed.
Research of heat mode of linear permanent magnetmotor for Long –Way one stage piston compressor
Authors: Tatevosyan A A
Published: February 2021

The paper discusses one of the design stages of an electrical complex of a linear motor of a low-speed long-stroke piston compressor based on a permanent magnet synchronous motor (SMPM). The article concernswith studying the thermal regime of the magnetic system. The temperature regime up to 800 Cis the limitation for the use of permanent magnets of the N40 series based on the NdFeB alloy, consequently the problem of determining the amount of heat released by the winding is urgent. To study the thermal regime, a prototype of a linear permanent magnet motor was developed and tested with a long-term current flow of 5 A. The efficiency of using a sectioned winding divided into eight coils especially whenthe coils switchedin two pairs is shown.
Study of the impact of speech-like interference on the psychological and emotional state of a human
Authors: Trushin V A , Zavodovskaya A I , Oveshnikov I A , Toporishchev E V
Published: February 2021

The protection of speech information should not only be as effective as possible, but also convenient for people who are in the protected room. Currently, the active protection devices, which are noise generators, are more often used for this purpose. The most effective is speech-like interference. But at the same time, it is noted that this type of interference creates more discomfort compared to others. This study is aimed at identifying the noise annoyance of speech-like interference, created on the basis of syllabic and word articulation tables, as well as reverberation speech-like interference. The experiments have shown that the most annoying is speech-like interference based on syllabic articulate on tables. The main negative consequences were headache, annoyance, and fatigue. Modification of the speech-like interference in the form of peak trimming improved the auditory perception of the interference by people, while the efficiency did not decrease.
The indicator R′ of the statistical significance for subgraph for motif discovery task
Authors: Yudina M N , Gam A V
Published: February 2021

The analysis of the statistical significance of subgraphs is carried out in dealing with solving the problem of detecting network motif in graphs of large networks. A new generalizing indicator of the significance of subgraphs is proposed. The indicator is intended to detect network motif when statistical methods are used to calculate the frequencies of occurrence of subgraphs. In fact that the subgraph in the studied network graph occurs more often than in the randomized versions of this graph (a sign of a network motif) is established statistically reliably.
The derivation Cramer-Rao lower bound for parameters of signals multiplied on window functions
Authors: Altman E A , Vaseeva T V , Aleksandrov A V
Published: February 2021

The article focuses on the refinement of the Cramer-Rao lower boundary for the single-tone signal amplitude for estimation methods using window functions. The Cramer-Rao lower boundary allows finding the minimum variance of the signal parameter estimate. There are formulas for variances estimations of the amplitude, frequency, and phase of harmonics of harmonic signals, but the known methods for their finding, including algorithms based on the maximum likelihood method, show results above this boundary. The increased variance of the estimate occurs due to the application of window functions on the original signal. The estimation of the accuracy of the parameters harmonics in case using the window functions usually done with a numerical simulation. In the article, the authors derive a formula for the minimum variance for amplitudes of harmonics in the case of the using the window functions. This derivation allows us to understand the mathematical meaning of the broadening the Cramer-Rao lower boundary when using window functions, and the resulting formula brings a faster and more accurate estimation of an amplitude accuration, in comparison with numerical simulation. According to the results of the experiment the calculations by the proposed formula and the numerical experiment data are the same.
Symmetry algebra of the time-dependent Schrödinger equation in constant and uniform fields
Authors: Boldyreva M N
Published: February 2021

The problems of constructing the symmetry operators of the time-dependent Schrödinger equation in the constant and uniform electric and magnetic fields with the use of the obtained operators in the method of non-commutative integration of linear differential equations are considered. A system of defining equations for the first-order symmetry operators is written. The paper investigates the structure of the symmetry algebras. It is shown that in the case of electric field the resulting algebra is the deformation of the Schrödinger algebra sch(1, 3).
On the greatest distance between two partitions of the finite set
Authors: Dronov S V
Published: February 2021

Consider the family Ξ of all possible partitions of a given finite set into disjoint parts. Suppose we have A ∈ Ξ, and there is reason to consider this partition basic from a certain point of view. The greatest value d *(A) of the special cluster metric d(A, B) is found, which is reached when its second argument runs through all B ∈ Ξ. The value of d *(A) turns out to depend on the structure of the basic partition A. Using the found value of d *(A), we propose a numerical coefficient whose value allows us to estimate the degree of difference between the basic partition and the newly built one. Such an assessment can help us to make a decision about the possibility of using the new partition instead of the basic one.
Unsteady temperature field calculation in the exothermic reaction
Authors: Fedorov S V , Tolstukha A S , Fedorov I V , Zhukovskyy V V
Published: February 2021

The paper presents the exothermic reaction monitoring method used in solving the thermal conductivity problems as well as in the process of solidifying the concrete foundation. The finite element method was applied. The problem was solved in a three-dimensional model taking into consideration the thermal characteristics dependence during the process of concrete hardening. The unsteady temperature field of the foundation block was calculated taking into account the forced pipe cooling. The given methodology is implemented in software and used for performing the three-dimensional unsteady temperature calculations. The software “Temper–3D” having a compliance certificate was developed according to the mentioned methodology. The program was registered in the Computer Software Register.
Differential equations application in progress prognosis of the pyrogenic succession process of grass and shrub layer of pine forest
Authors: Moskvitin A V , Goltyapin V V
Published: February 2021

This article is devoted to the differential equations system application of the Morino – Voight mathematical model for predicting the process of pyrogenic succession of a pine forest. For the first time, the results of predicting the process of pyrogenic succession according to the Morino – Voight model were compared with real data characterizing the restoration of a pine forest after a fire.
Car Service Optimization Based on Simulation
Authors: Revina I V , Trifonova E N
Published: February 2021

The article presents the results of optimizing the service center operation. The IDEF3 notation was used to analyze the logical sequence of processes performed in the car center divisions. The developed discrete-event simulation model “AS-IS” made it possible to identify “bottlenecks” in the work of the car center. The involvement of experts and the use of the method of apriori ranking of factors allowed determining the impact of a number of factors on the work of the service center and the directions for improving the work. Changes in organizational, material and technical factors and the development of “TO-BE” simulation model allowed determining the optimal parameters for the service center operation. As a result of the business process reengineering, the following changes were made: staff schedule and assignment of employees to work; the number of service posts; an electronic queue and document management system. These changes allowed increasing the profit of the service center by 1.9 times.
Computer-aided simulation of high-dimensional event-continuous systems
Authors: Shornikov Yu V , Popov E A
Published: February 2021

A comparative analysis of efficiency of explicit methods with error and stability control, semi-implicit (m, k)-methods, and implicit methods implemented in the modelling and simulation environment ISMA is presented. The Akzo Nobel Central Research laboratory’s model of a tumour penetrated by antibodies is used as the test problem. The computer model in the LISMA language after applying the method of lines is given. Performance of the numerical integration algorithms is measured for different spatial variable discretization steps.
Equational noethericity for graphs and hypergraphs
Authors: Treier Alexander
Published: February 2021

In 1999th G. Baumslag, A. Miasnikov and V. Remeslennikov posted the following problem. Let G be a group. Does a noethericity by equations in one variable imply a nothericity by equations for the group G in the language with constants from G? Same question may be asked for graphs and hypergraphs. It is shown in the article that the answer to the question above is positive for graphs and is negative for hypergraphs.
Two-grid method for the stationary Burgers equation
Authors: Zadorin N A , Shagaev S B
Published: February 2021

A two-grid method is investigated for solving the boundary value problem for nonlinear ordinary differential equation of the second order with a small parameter at the highest derivative. The solution to the problem has large gradients in the boundary layer region. The application of the central difference scheme on the Shishkin and Bakhvalov grids is investigated. Previously, this scheme was investigated only in the case of a linear equation. It is shown that in the case of the considered nonlinear problem, this scheme on the Shishkin and Bakhvalov grids has a convergence uniform in a small parameter. On the basis of computational experiments, it is shown that the use of the two-grid method leads to a reduction in computational costs when implementing the difference scheme. It is shown that in the two-grid method it is effective to apply the Richardson method to improve the accuracy of the difference scheme.
Fuzzy Discrete Problems with Summed Objective Function and their Crisp Bi-Objective Modifications
Authors: Zakharov A O , Kovalenko Yu V
Published: February 2021

Discrete optimization problem with fuzzy input parameters having the form of triangular fuzzy numbers is considered. Objective function is given by the sum of some subset of fuzzy input data. Crisp model with two criteria: objective function and its membership function is formulated. We propose an algorithm which constructs the Pareto set of this bi-criteria problem. We consider particular fuzzy discrete problems, such as scheduling problems, routing problems, problems of selecting a subset of elements, maximum matching problems, where the obtained results could be applied.
Optimization of the control system parameters using the genetic algorithm
Authors: Denisova L A , Alekseytsev D M , Meshcheryakov V A , Denisov O V
Published: February 2021

The method for parametric optimization of an automatic control system is proposed. The criterion for the quality of the functioning of the system includes control accuracy and control costs. The method takes into account the change in the operating conditions of the control object and the influence of random disturbances. A combination of a genetic algorithm procedure in MATLAB and system simulation in Simulink is proposed. Recommendations for choosing the optimal values of the system parameters are passed on to the operator of the technological process.
Multistage biquadratic filter for measuring of electrical power consumption parameters
Authors: Gordeev O I , Zakharenko V A
Published: February 2021

The relevance of developing technical solutions to reduce the number of calculation operations and the amount of memory required for the operation of typical structural elements of programs that implement digital signal processing in problems of continuous measurement of electrical parameters is shown. The use of the multi-stage biquadratic filter for solving these problems is proposed. The theoretical comparison of the structure of the above-mentioned filter with the known structures of digital filters is carried out. An experimental comparison of a specific implementation of the multi-stage biquadrate filter with the similar implementation of a digital filter of a known structure is carried out.
Recognition of micro-objects with adaptive models of image processing in a parallel computing environment
Authors: Jumanov I I , Djumanov O I , Safarov R A
Published: February 2021

Scientific and methodological foundations for optimizing the processing of micro-objects, in particular, pollen grains, have been developed on the basis of models and methods of preliminary information processing with mechanisms for filtering, identifying, and using textural, specific characteristics, and geometric features of images. The efficiency of image filtering mechanisms is investigated based on the use of statistical control rules, adaptive two-threshold control, trend functions, and control of the contour description error, traditional detectors of random noise, and interference. The mechanisms of image identification using biquadratic, orthogonal algebraic polynomials, 4th order splines are proposed. A technique for optimizing image identification by finding a function by its integrals in a family of straight lines based on the Mellin and Fourier transforms has been developed. Combined models with mechanisms for smoothing reference points, segmentation of contours, filtering with detection of changes in dynamics, optimization by the conjugate gradient method, time relaxation have been built. A software complex for the recognition and classification of images of pollen grains in C ++ has been developed, which includes testing identification algorithms based on the Daubechies spline function, orthogonal algebraic polynomials of 4, 8 orders in the parallel computing environment “CUDA”.
Using computer simulation in designing new products
Authors: Kramorov A V , Yanishevskaya A G
Published: February 2021

Design of new products and mechanisms is continuous and complicated process. The complexity of new products is explained by increased requirements for reliability and wide functionality of new products for its competitiveness. At the same time, design time is reduced by replacing natural tests with computational experiments and the widespread use of modern computer-aided design systems (CAD systems). This article presents the design of the bridge laying mechanism of tank bridge layer using modern CAD systems.
Search for the optimal method for obtaining estimations for an automated magnetotelluric signal processing system
Authors: Lavrukhin A A , Lobov K V , Tukanova A S , Onufriev A S
Published: February 2021

The problem of obtaining estimates of impedance frequency characteristics in the magnetotelluric sounding method is considered. A variational algorithm is proposed for research through a variety of means of estimation from the point of view their accuracy and efficiency. The results of computational experiments on the processing of synthetic signals are presented, which represent indicators of the accuracy and efficiency of some estimation methods. The proposed approach can be used in the development of algorithms and software for the embedded system for recording and processing signals, as well as applied software for an automated system for processing signals from magnetotelluric sounding method.
Passive orientation of the parts in the mechanical disk hopper feeding device with an annular orientator and radial grooves
Authors: Pantyukhina E V , Preis V V , Pantyukhin O V
Published: February 2021

The paper considers mathematical models describing the process of passive orientation of axisymmetric parts in the form of the bodies of rotation with implicit asymmetry at the ends in the mechanical disk hopper feeding device with an annular orientator and radial grooves made on a rotating disk. The developed mathematical models make it possible to estimate the boundary conditions under which the reliable orientation of the parts and the time of orientation of the parts will be ensured, depending on the geometric parameters of the part, the coefficient of sliding friction of the part against the guide surfaces, the structural and kinematic parameters of the hopper feeding device.
Improving the accuracy of homing mobile objects with semi-passive method by reducing the time of forming the control force
Authors: Pavlov V I , Belousov O A , Dorokhova T Y , Belyaev M P , Trapeznikov E V
Published: February 2021

The options of relative motion of a homing object with a semi-passive method and a mobile end waypoint are considered. For the given options, estimates for the required transverse acceleration of the homing object and the miss distance are given. It is shown that to reduce the miss in homing by method of proportional guidance it is advisable to reduce the time for the control force formation, and the decrease of distance of switching off the control system, when in the object control system only angular information about the current position of the end way points and motion parameters of their own mass center is used.
Features of the CIE76, CIE-94, and CIE-2000 methods that affect the quality of the determining process of the image average color
Authors: Proskuriakov N E , Yakovlev B S , Arkhangelskaia N N
Published: February 2021

Results of pilot studies of the difference in color – the indicator of Delta E determined by CIE-76, CIE-94, CIE-2000 at determination of average color of the digital image are provided. Based on experimental data features of behavior of CIE-76, CIE-94, CIE-2000 calculators on condition of their use for determination of average color of different graphic formats of images were revealed. The research showed that CIE-76 has always the greatest values of the indicator of Delta E. It is revealed at all studied formats of images, irrespective of the prevailing color on the image. In addition, it was established that CIE-94, CIE-2000 show very insignificant deviations from each other and significantly differ from Delta E’s indicators of CIE-76 at stages of the maximum reduction of the image. In the analysis of graphic dependences of behavior of the indicator of Delta E it was revealed that CIE-76, CIE-94, CIE-2000 behave probably, saving the main peaks of values. The software in the Python programming language, which showed the efficiency and capability, was developed to measure average color at different images.
Features and consistent patterns of changes in properties of the system AIIIBV - ZnTe solid solutions
Authors: Kirovskaya I A , Novgorodtseva L V , Vasina M V , Mironova E V , Nor P E , Yurieva A V , Chernous N V , Zhigarova O Yu , Krasheninin V I
Published: February 2021

By the methods developed for the InSb-ZnTe, GaSb-ZnTe systems, in the regions of mutual solubility of the initial binary compounds (InSb and ZnTe, GaSb and ZnTe), solid solutions (InSb)x(ZnTe)1-x, (GaSb)x(ZnTe)1-x have been obtained.

X-ray, IR and Raman spectroscopic, electrophysical studies of the obtained solid solutions (in comparison with the initial binary compounds and among themselves) have been carried out, following the results of which the obtained solid solutions have been certified as substitutional solid solutions with a cubic sphalerite structure. The information on multicomponent diamond-like semiconductors has been expanded.

The acid-base properties of the InSb-ZnTe, GaSb-ZnTe systems components surfaces, varying in composition from weak acid to weakly basic, have been studied.

General and distinctive features in the “behavior” of the InSb-ZnTe, GaSb-ZnTe systems solid solutions have been revealed. The relative influence of binary components on the type of dependences “property – composition” has been demonstrated and explained.

Practical recommendations have been given for the use of solid solutions with the lowest pHiso values as materials for the manufacture of sensors for main gases trace contamination.
Analysis of the geometric features of T-x-y diagrams with melt immiscibility for silicate systems
Authors: Vorob’eva V , Zelenaya A , Lutsyk V
Published: February 2021

Analysis of the geometric structure of phase diagrams for ternary systems with the two immiscible liquids has been carried out. T-x-y diagrams with the both types of the monotectic equilibriums (univariant and invariant ones) have been analyzed. Three-dimensional computer models of T-x-y diagrams for the four silicate systems with mono- and invariant equilibriums and different variants of the immiscibility surfaces location have been built. T-x-y diagram of the ZrO2-SiO2-Al2O3 system includes one immiscibility cupola, located in the ZrO2 crystallization field, which adjoins the ZrO2-SiO2 side. The 3D model of T-x-y diagram includes four invariant transformations: peritectic P: L+ZrO2+SiO2→R2, quasi-peritectic Q: L+ZrO2 →R1+R2, two eutectic E1: L→ZrO2+Al2O3+R1, E2: L→SiO2+R1+R2. Five surfaces of liquidus, which correspond to the beginning of primary crystallization of three initial components and two binary compounds R1=3Al2O3·2SiO2 and (congruently melting) and R2=ZrO2·SiO2 (decomposed without liquid) are formed in the system. T-x-y diagram TiO2-ZrO2-SiO2 is characterized by one eutectic E: L→TiO2+SiO2+ZrO2·TiO2 and one quasi-peritectic Q: L+ZrO2→SiO2+ZrO2·TiO2 transformations and includes two immiscibility surfaces from the sides of TiO2-SiO2 and ZrO2-SiO2 binary systems. FeO-SiO2-Fe2O3 system with common immiscibility cupola, that prolongs from the system FeO-SiO2 to the system SiO2-Fe2O3, is characterized by three invariant transformations of eutectic type, and one metatectic transformation V: B1 →L+B2+C, which corresponds to the transfer from high-temperature allotropy of silica (B1 - cristobalite) to the low-temperature one (B2 – tridymite). T-x-y diagram KAlSi2O6-Fe2SiO4-SiO2 has two immiscibility surfaces: one of them adjoins to the Fe2SiO4-SiO2 binary system and the second one is located on the Fe2SiO4 and tridymite liquidus surfaces, dividing the univariant curve on their boundary into two parts, and has three points of the maximum and three points of the minimum. Using of the computer models of T-x-y diagrams allows you to take into account different variants of the geometric structure of the investigated silicate systems.
Hot spots of opportunity for improved cropland nitrogen management across the United States
Authors: Roy Eric D , Hammond Wagner Courtney R , Niles Meredith T
Published: February 2021

Nitrogen (N) is a vital input to crop production, but its excess use is a cause of environmental and human health problems in many parts of the world. In the United States (US), as in other nations, reducing N pollution remains challenging. Developing effective N policies and programs requires understanding links between cropland N balances (i.e. N inputs minus N harvested in crops) and potential contributing factors. We present novel insights into these links using a national county-level assessment and propose a criteria-scoring method to inform US N policy and programs. First, we characterize cropland N balances across the US in 2011–2013 and identify counties (∼25%) where N input reductions are less likely to result in crop yield declines. Second, we identify agronomic, environmental, social, demographic, and economic factors correlated with N balance, as well as counties that are underperforming based on these characteristics. Finally, we employ criteria scoring and hot spot analysis to identify 20 spatial clusters of opportunity for improved cropland nitrogen management. These hot spots collectively account for ∼63% of total surplus N balance for croplands but only ∼24% of cropland area in the US. N flows for these hot spots indicate variable opportunities across the US landscape to improve cropland N balances by reducing N fertilizer use, better managing manure N, and/or increasing N use efficiency. These findings can guide future efforts to integrate N balance into regulatory and voluntary frameworks in US policy and programs.
Intelligent Regulation System of Central Heating Pipe Network based on Internet of Things
Authors: Chen Yiming , Du Xiaogang , Liu Yuhang , He Jiang , Chen Wenli
Published: February 2021

The level of heating quality determines the comfort level of residents’ indoor life in winter. In order to effectively improve the hydraulic imbalance of the pipe network, improve the self-adjusting ability of the pipe network and reduce manual operations. This paper proposes an Intelligent Regulation System for Centralized Heating Pipe Network based on the Internet of Things, and takes the No.3 building of Guangxian Jiayuan Community in Tianjin as a pilot project to select the flow rate and return water temperature in front of the representative users in the low, middle and high floors Measure the date and analyze it. The results show that the flow of the indoor pipe network of the user runs smoothly, and the change range is within 0.05 m3/h, and the change range of the return water temperature of the pipe network is maintained within 3 °C. The Intelligent Regulation System of the Pipe Network has a good self-regulation capability.
An Improved Calculation Method of Coal Consumption Index for Heating in CHP with a High Back Pressure Turbine
Authors: Sun Jian , Ma Shicai , Huo Cheng , Ge Zhihua , Zhou Shaoxiang
Published: February 2021

CHP (combined heating and power) system is playing an important role for district heating, meanwhile, the latent heat of exhausted steam at the thermal power plant is discharged to atmosphere directly, which is often more than 30%. Waste heat recovery is of great significance for reducing coal consumption indicators for heating in CHP system. The method by replacing different rotors of the LP (low pressure) cylinder is presented and experimented with a 140MW turbine, whose exhausted steam could be recovered completely. Besides, an improved calculation method of coal consumption index for heating is discussed. The improved mathematical model is used to calculate the influence of exhaust pressure on steam turbine power generation efficiency, which improves the accuracy of heating coal consumption. This experimented coal consumption index for heating is 12.7 kgce/GJ, which is much lower than the traditional CHP system (20 kgce/GJ).
Path Analysis of Implementing Carbon Neutral Target in Customer Side of Power Grid Company
Authors: Tang Wei , Weng Yuyan , Zhang Yu , Cao Xiaodong
Published: February 2021

China puts forward the goal of carbon neutralization, which puts forward new requirements for China’s energy production, consumption and utilization. This paper analyzes the impact of “power supply + energy efficiency service” implemented by the grid company on the carbon reduction target, designs the implementation path in the future, and puts forward relevant suggestions.
The Viscosity of Oil Influence on the Working Characteristics of Electric Submersible Pump under Variable Speed
Authors: Zhao Yi , Zhao Deyin , Zhong Yongqiang , Zhao Yan
Published: February 2021

The viscosity of oil in different oil fields varies greatly, and the widespread use of polymer flooding also has a great impact on the viscosity of the oil. The submersible electric pump is one of the main mechanical oil recovery methods, and its working performance directly affects the production efficiency of the oil well. The application of the Computational Fluid Dynamics (CFD) method to study the effect of viscosity on the internal and external characteristics of a submersible electric pump with variable speed is an effective complement to the experimental method. The inner flow passages of the impeller and the vane of the pump (model is Q10.) were selected as a fluid domain for the CFD study. The results show that As the viscosity increases from 1 mPa·s to 215 mPa·s, the efficiency of the electric submersible pump decreases from 56.8% to 49.7, the power consumption increases from 142W to 163W, and the head decreases from 6.8m to 5.6m. This paper proposes the use of CFD technology to study the internal and external characteristics of electric submersible pumps under variable speed and variable viscosity conditions.
The Study of Thermal process and Temperature Calibration for a Vacuum Drying Oven Based on Numerical Simulation
Authors: Liu Ying , Zhang Wen , Xu Yang , Zhang Jing
Published: February 2021

Vacuum drying technique is widely used in food a processing, pharmaceutical and other industry which needs to be calculated regularly. In order to establish temperature calibration method for vacuum drying oven, temperature profile needs to be studied. In this paper, a three-dimensional (3D) unsteady mathematical model has been developed to study heat transfer in a vacuum drying oven. Governing equations are discretized in implicit form by using the control volume method. PRESTO! scheme was used for the discretization of the pressure modified equation. SIMPLE algorithm is adopted to solve the coupling of pressure and velocity. The natural-convection flow forced by buoyancy force was numerically calculated based on Boussinesq assumption. Results of the model calculation showed that temperature distribution in the vacuum drying oven significantly changed when the pressure in the oven is close to vacuum. Temperature uniformity in the vacuum drying box increases with the increase of vacuum degree. It is not appropriate to directly investigate the temperature uniformity of the vacuum drying oven by using JJF 1101-2019. The results can be used to lay a theoretical foundation for the establishment of calibration method for vacuum drying oven.
Determination of dynamic parameters of the elastically supported beam system model by optical and numerical methods
Authors: Gridnev S , Ravodi I , Volko V
Published: February 2021

The article describes the design of a test facility that designed and manufactured by the authors for parametric studies of the features of free and forced vibrations of elastically supported dynamical systems. The results of a full-scale experiment are presented in the article, during which a frequency analysis of a beam with an intermediate elastic support is performed. Measurements are made with the use of the optical method of determining the movements and inductive sensors. A finite element model of the test facility was built in the Midas NFX environment with the aim to verify and evaluate the results. The results of the modal analysis performed for the finite element model of the test facility are compared with the natural frequency spectra obtained as a result of experiments. Conclusions are drawn about the prospects of using the test facility, the accuracy of the measuring equipment used, and about the way the finite element model built in the Midas NFX program environment corresponds to the full-scale model of the dynamic system in terms of its dynamic characteristics.
Different models of connection flexibility in dynamic analysis of plane frame systems
Authors: Tran T T V , Tran T H
Published: February 2021

Nowadays, in Vietnamese structural design standards for steel frames and semi-precast reinforced concrete structural frame systems, the connections of beams and columns are commonly considered as perfectly hinged or rigidly fixed. This is adopted because of the simplicity in design and analysis procedure but it is not consistent with the condition taking into account actual behaviour in practice of structural systems. The connections between columns and beams have partial restraint depending on the type of used connections. The presence of connection flexibility tends to reduce frame stiffness in comparison with the case of fully fixed connection and hence increases the frame’s natural period of vibration. However, it is also more time required because of complexity of analysis process with consideration of connection flexibility in the case of lack of suitable analysis method. The paper presents the dynamic analysis of plane frame systems with different models of semi-rigid connections using finite element method. The used models in dynamic analysis are rotational spring and rotational-lateral spring. The analysis procedure was implemented using MathCad programming software and the results of this study will obtained by conducting of numerical examples. From there, the conclusions and recommendation of dynamic analysis for steel and semi-precast concrete frames with models of connection flexibility and the differences between used models will be proposed.
Using COSMOSWORKS abilities in construction glass strength research
Authors: Alpatov V , Veremeenko O Y
Published: February 2021

Considered the issues of definition maximum acceptable load on supporting construction, made of glass. Object of research is a complex construction – insulated glass unit. Glass unit has two loaded layers of three in triplex and central layer – air chamber. Air chamber is formed by rubber layer, connecting external layers of triplex by perimeter. Glass unit loading is single-sided, only on top layer. Glass unit fastening was made only in four corner points. Researches were made in program complex COSMOSWORKS. Maximum acceptable load is searched by iterative calculation with step-by-step increase of calculation load on model. Established, that covering deformation and the stress distribution in them changes linearly. The value of maximum acceptable load for glass unit with special geometrical and physical characteristics was calculated. In this article the optical, thermal and other glass unit properties were not considered. The article presents the results of glass unit analysis when only mechanical action is applied to them. Temperature effect on glass units was not considered in this article.
Design and modeling of glulam beams with holes
Authors: Pełczyński J , Brodniewicz P , Al Sabouni-Zawadzka A , Gilewski W
Published: February 2021

The paper presents a sketch of design recommendations and numerical simulations of stress distributions in perforated double-tapered beams made of glued laminated timber, taking into account the reinforcement used. Conscious design requires, according to the authors opinion, calculations performed using the finite element method. The analysis presented in the paper concerns three possible positions of the opening in the apex zone. It is recommended to position the opening halfway up, as it causes the least stress disturbance in the beams. Bottom position is definitely not recommended, as stress disturbances are large and cannot be levelled with transverse reinforcement. Reinforcement allows for the reduction of stresses in the range from several to several dozen percent.
The use of included stiffeners to strengthen the frames of one-story industrial buildings
Authors: Yu Veremeenko O , Alpatov V Yu
Published: February 2021

The article considers issues of industrial buildings frames strengthening by the introduction of stiffening elements at the change of calculated seismicity. The principle of materials concentration in the form of stiffness elements with included connections is used. The degree of their influence on the work of building frame is estimated. In this case, the work of coating disk as an element distributing horizontal forces changes. The main dependencies for gap definition determined by the reinforced concrete frame movements, at which moments in the lower section of the columns reach the limit values, are determined. Thus, in the process of influence the seismic force will remain approximately constant, as the total stiffness will be slightly higher than the initial columns stiffness. Introduction of rigidity elements into the frame should be accompanied by corresponding measures for strengthening of foundations for steel supports.
Assessment features of bearing capacity of large-span covering constructions in the reconstruction of religious Orthodox buildings
Authors: Shepelev A P , Ibatullin R R
Published: February 2021

The research object is the middle part and the refectory overlap of the temple in the honor of the Holy Kosma and Domian Asiysky, located in the village of Ssezzhe of Bogatovsky district of Samara region. At the time of the works, the object was undergoing a large-scale reconstruction. Based on the data of the detailed technical condition survey of the building structures of the temple overlap, the authors made calculations in a physically nonlinear setting, allowing to fully assess the stress-strain state of the monolithic reinforced concrete structure of the middle part and refectory, which is a complex unified system of thin-walled spatial structures of different contours of the middle surfaces. The recommendations on the completion of the overlap construction and its further operation were developed on the basis of the calculations results analysis.
Hydraulic aspects of the layout of head structures during water intake from lowland rivers
Authors: Bazarov D , Markova I , Norkulov B , Vokhidov O
Published: February 2021

The article discusses various types of new improved dam water intake hydroelectric systems, sedimentation facilities, sediment control devices on rivers and canals with a rational layout. The results of the analysis of studies on the use of the theory of transverse circulation and methods of artificial, active regulation of the structure of the water intake flow are presented, which has become widespread in world practice and is the main one for creating an effective design of water intake headworks for pumping stations and hydropower facilities that provide them with reliable protection from sediments. The author of the article, on the basis of numerous experimental data obtained in various countries of the world, makes a conclusion about the effectiveness and prospects of using front-type structures with more than 50% water intake. The design of water intakes of this type has been significantly improved; they can be successfully used in various conditions, including on Mountain Rivers. The author draws attention to the development of a new design of the pioneer ditch, which ensures the efficient passage of bottom sediments into the downstream of the structure, which prevents intensive silting of the reservoir basin by bottom sediments and improves the efficiency of the dam water intake.