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Information deviations are inevitable under the influence of multifarious factors in real-world traffic, leading to discrepancies between the information obtained by automated vehicles (AVs) and the true information. However, due to the lack of an appropriate analytical model that incorporates various information with deviations, we have limited knowledge of the relationships between different types of information deviations and anomalous dynamics of AVs and traffic flow. This study aims to fill this gap. Specifically, we first expound the possible information deviations in AVs, upon which we categorize them into three types: velocity, gap, and driving decision deviations. Subsequently, we modify the input parameters in the adaptive cruise control (ACC) model that calibrated using real experimental data to capture the car-following dynamics of AVs with information deviations. By using H ∞ control theory and characteristic equation-based method, we derive the local and string stability criteria of traffic flow with AVs, so as to discern the effects of various system factors on traffic flow stability. Experimental results show that information deviations could provoke abrupt acceleration or deceleration of AVs, leading to instability in automated traffic flow, oscillation, and even collision accidents. Overall, this paper unveils the influence mechanisms of diverse information deviations on AVs and traffic flow, providing valuable suggestions and theoretical guidance for the future development of AVs. [ABSTRACT FROM AUTHOR]

A reduced-dimension (RD) method based on the proper orthogonal decomposition (POD) technology and the linearized Crank–Nicolson mixed finite element (CNMFE) scheme for solving the 2D nonlinear extended Fisher–Kolmogorov (EFK) equation is proposed. The method reduces CPU runtime and error accumulation by reducing the dimension of the unknown CNMFE solution coefficient vectors. For this purpose, the CNMFE scheme of the above EFK equation is established, and the uniqueness, stability and convergence of the CNMFE solutions are discussed. Subsequently, the matrix-based RDCNMFE scheme is derived by applying the POD method. Furthermore, the uniqueness, stability and error estimates of the linearized RDCNMFE solution are proved. Finally, numerical experiments are carried out to validate the theoretical findings. In addition, we contrast the RDCNMFE method with the CNMFE method, highlighting the advantages of the dimensionality reduction method. [ABSTRACT FROM AUTHOR]

Constitutive relations and a method for analyzing the behavior of fiberglass during longitudinal bending under the combined influence of force factors and an alkaline medium were proposed. Both natural and numerical experimental designs were outlined. A new approach to solving the problem of longitudinal bending of a fiberglass beam with initial failure was introduced, without involving geometrically nonlinear relations. This approach proved to be applicable when the resulting beam configuration is a flat curve. The results of numerical calculations were presented. In the first case, the beam with initial failure was studied using the new approach along with the finite element method (FEM). In the second case, for verification, the problem was solved in a geometrically nonlinear formulation. The results obtained showed a strong agreement.

The distribution of the deep geothermal field and the tectonic thermal control mode in the Yingshan area were not understood systematically, which would bring in constraints to the sustainable exploration of local geothermal resources. Based on the field survey on continuous temperature, fracture measurements in the outcrops of granite rock, slug-test, and pumping test in the boreholes, a three-dimensional model coupling fluid flow and heat transfer process in fractured rock reservoir was established. Then the distribution of fluid pressure temperature and the Darcy velocity in the whole geothermal reservoir were calculated considering different treatment combinations of main faults. The results show that the deep temperature field and fluid pressure distribution are greatly affected by the faults system. At the location of bedrock and impermeable fault, the fluid movement is very weak, and the heat transfer is mainly controlled by heat conduction, while in the high permeable fault, it is mainly controlled by heat convection. Low temperature and fluid pressure occurred in the deep, high-permeable fault zone whereas high fluid pressure occurred in the impermeable fault zone. At a depth larger than 2000 m, the zones with high temperatures and intense hydraulic exchange coincide with the conductive fault zones, which indicates that the high-permeable faults are the most important channel for seepage and heat transfer in the reservoir. Therefore, the northeast faults are the dominant channel for fluid migration and heat conduction in the Yinshan area. Hot water migrates upward along the northeast faults and is blocked by the north-south fault. The hot spring is formed at the intersecting position of two groups of faults. This study is helpful for scientific, sustainable exploration of geothermal resources in the Yingshan area.

This work is devoted to the technology developed by the authors that allows one for fixed values of parameters and tracing by parameters to calculate stationary solutions of systems with delay and analyze their stability. We discuss the results of applying this technology to the Marchuk–Petrov antiviral immune response model with parameter values corresponding to hepatitis B infection. The presence of bistability and hysteresis properties in this model is shown for the first time. [ABSTRACT FROM AUTHOR]

This paper focuses on the use of vibration measurements for the purpose of cost-effective performance evaluation for the safety management and maintenance of Japan's social infrastructure like bridges. Since modal properties are often used to diagnose damage of structures by analysing their changes, various modal identification methods have been developed in the past few decades. Among these, the FDD method has still attractive attention because of its simplicity and practicality. It is also highly applicable to simultaneous observation at multiple points and even complex modes can be identified instantly. On the other hand, the applicability of this method to impact tests applied to evaluate the condition of structures has not been sufficiently discussed to date. In this study, we will clarify the applicability to impact tests by reconstructing the theoretical background of the FDD method. Furthermore, we will show from theory that when there is a correlation between inputs, higher-order singular values, which should be noted when applied to impact tests, will be affected. The conclusions obtained from the reconstruction of the theoretical background will be verified based on numerical experiments and actual observation records. [ABSTRACT FROM AUTHOR]

Copyright of Hydrogeology & Engineering Geology / Shuiwendizhi Gongchengdizhi is the property of Hydrogeology & Engineering Geology Editorial Office and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The surge caused by rock mass instability and landslide in reservoir area will poses a great threat to the safety of hydraulic structures and downstream. The rock landslide mass may fracture and break during the landslide process, affecting the subsequent surge disaster process. The strength and friction coefficient of rock mass are the important factors that affect the fracture and fragmentation of rock mass. Through the three-dimensional numerical experiment of landslide surge, the whole process of landslide surge under different rock mass strength and friction coefficient conditions was simulated, and the motion characteristics and surge characteristics of landslide were analyzed. The results show that with the increase of rock mass strength, the degree of landslide fragmentation gradually decreases, the velocity and kinetic energy gradually increase, and the maximum wave height and maximum climbing height of surge also gradually increase. What's more, the landslide mass with high rock mass strength enters into the channel at a high speed, in an extreme case, it may even impact the rock mass on the opposite bank to cause new landslide disasters. Moreover, the smaller the friction coefficient is, the greater the velocity and kinetic energy of the landslide mass are, and the greater the maximum wave height and the maximum climbing height are. When the friction coefficient is very small, the rock mass with low strength may not break during the sliding process along the sliding surface, resulting in a sudden increase in the maximum wave height and maximum climbing height of the surge. [ABSTRACT FROM AUTHOR]

This work explores the mathematical modeling of thermophysical processes within a thermoelectric device (TED) designed for brain cooling. The pressing need to mitigate cerebral hyperthermia, a condition triggered by factors such as strenuous physical activity, elevated ambient temperatures, and various pathological conditions, underscores the significance of this research. The focus of this study is a specialized design—a cooling helmet encompassing the scalp, frontal, and temporal regions. This helmet interfaces with the head through a block of thermoelectric modules (TEM) to facilitate cooling. The mathematical model developed for this research addresses three critical components (i) temperature field calculation, (ii) TEM parameter optimization, and (iii) heat dissipation system. The outcomes of this mathematical modeling endeavor yield temperature profiles at key control points within the TED, depicted in spatial and temporal coordinates, contingent upon the supplied TEM power. Furthermore, the study uncovers essential energy parameters for the thermomodules, encompassing their particular types sourced from the standard TEM selections offered by "Cryoterm" LLC, the manufacturer. Notably, the theoretical investigation into TEDs for brain cooling unveils a pragmatic remedy. The integration of two typical DRIFT-0.8 TEMs from the specified manufacturer within the TED design demonstrates the capacity to reduce brain temperature to 291 K. The characteristics of these TEMs display variation within predefined thresholds, with power outputs spanning from 20 to 80 W, an average temperature difference of 50 K across junctions, supply currents ranging from 3 to 11 A, and power consumption levels ranging from 100 to 500 W. These attributes are complemented by coefficient of performance values ranging from 0.1 to 0.5. This research not only sheds light on the feasibility of employing thermoelectric devices for brain cooling but also lays the foundation for addressing cerebral hyperthermia and advancing neuroprotection applications across various clinical and non-clinical contexts. [ABSTRACT FROM AUTHOR]

The study of airflow patterns at the ends of dead-end mine workings is crucial for optimizing underground mining ventilation systems. Understanding these patterns forms the basis for designing and implementing effective ventilation strategies. Previous studies have shed light on the behavior of the main vortex and the formation of stagnant zones in such environments, but these insights remain fragmented and call for a more systematic exploration to integrate them into a comprehensive theory. This paper presents the results of a thorough field investigation into the forced ventilation behavior in a dead-end mine working with a significant cross-sectional area (29.2 m2). We evaluated the impact of varying the setback distance of the ventilation duct’s end from the working face at intervals of 10, 15, 17, 19, and 21 m. The experimental design included precise measurements of turbulent airflow velocities at 25 carefully chosen points (in a 5x5 grid) for each setback distance, covering the area from the working face to beyond the end of the ventilation duct. This included additional measurements taken 1 meter and 10 meters past the termination of the ventilation duct, moving towards the entrance of the working area. The fieldwork was carried out in a typical dead-end stope at the Kupol gold-silver mine in the Chukotka Autonomous District, created by drilling and blasting. The volume of fresh air delivered to the working was maintained at a consistent rate of 17.4 m3/s across all scenarios, aligning with the mine’s standard air flow rate derived from the ventilation requirement for exhaust gases emitted by internal combustion engines of Load-Haul-Dump (LHD) machinery. With the duct’s terminal cross-sectional area at 0.8 m², this resulted in an inflow velocity averaging 21.75 m/s. Additionally, we included insights from three-dimensional numerical simulations performed in ANSYS Fluent, focusing on steady-state air movement and developed turbulence within the dead-end space. A comparative review of both empirical and modeled data shows that the ventilation jet, for all tested setback distances up to 21 m, successfully delivered air to the working face, where it then dispersed and initiated reverse flow patterns. These experiments led to the formulation of a linear relationship between the maximum relative velocity (compared to the initial jet velocity) at a distance of 1 m from the working face and a key geometric factor of the ventilation setup. This factor is the ratio of the duct’s setback distance to a characteristic dimension of the cross-sectional area, calculated as the square root of the cross-sectional area.

Organizational innovation performance is considered to be the key to maintaining competitiveness and achieving sustainable development in modern enterprises. Deviant innovation refers to that employees improve their working methods without the permission of the organization, break through the constraints of existing rules and achieve high performance. Additionally, Deviant innovation behavior can also stimulate the enthusiasm of other members of the organization. In order to study the evolutionary game rules of strategic interaction between enterprises and employees in the process of deviant innovation, this paper constructs a 2*2 asymmetric payoff matrix, and uses numerical simulation to show the influence of different values of decision parameters and changes of initial conditions on the evolutionary results. The research reveals that the interaction game between employees' deviant innovation behavior and enterprise enhancement of organizational innovation performance is a complex and significant topic. It is found that when enterprises actively improve organizational innovation performance and employees implement deviant innovation behavior, both sides engage in positive game interactions, maximizing enterprise benefits. However, when enterprises passively enhance organizational innovation performance but employees engage in deviant innovation behavior, it may lead to conflicts between the two parties. The research findings provide relevant strategies for employees to correctly implement deviant innovation behavior and for enterprises to enhance organizational innovation performance. [ABSTRACT FROM AUTHOR]

To solve the constrained optimization problem, a new algorithm WDFSO is obtained by combining the exterior penalty function method and an improved snake optimization algorithm. Firstly, the constrained optimization problem is transformed into a series of bound-constrained optimization problems by the exterior penalty function method. Then, the improved snake optimization algorithm based on the oppositional learning of the centroid variation strategy and the population classification strategy is used to solve the bound-constrained optimization problem, and obtain the solution of the constrained optimization problem. In order to verify the effectiveness of WDFSO algorithm, 19 benchmark constrained optimization problems in CEC2006 are selected for numerical experiments, and the Wilcoxon rank sum test is used to prove the algorithm significance. The experimental results show that WDFSO algorithm has higher convergence accuracy and better stability than the comparison algorithms. Finally, WDFSO algorithm is applied to solve two engineering constraint optimization problems, and the results show that WDFSO algorithm has better performance. [ABSTRACT FROM AUTHOR]

The authors present a new mathematical model for solving a static symmetric boundary-value problem for a layer weakened by a through hole with ends covered with a diaphragm. A new method based on a system of three singular integral equations is developed and tested numerically. A high-precision numerical analysis shows that as the thickness of the layer increases, relative circumferential stress increases as well. If one of the radii of the elliptical hole decreases, relative circumferential stress also increases. The corresponding graphs are presented. [ABSTRACT FROM AUTHOR]

The paper presents a new mathematical model for the solution of a static symmetric boundary-value problem for a layer weakened by a through hole with ends covered with a diaphragm. A new method based on a system of three singular integral equations has been developed and tested numerically. As a result of a high-precision numerical study, it was found that with an increase in the thickness of the layer, an increase in the relative circumferential stress occurs. With a decrease in one of the radii of the elliptical hole, an increase in the relative circumferential stress is also observed. The paper presents the respective dependency graphs. [ABSTRACT FROM AUTHOR]

Relevance. Groundwater is the main source of industrial and technical water supply for mining facilities. The geological structure of the studied areas can be complicated by various factors that make it difficult to search for and localize groundwater. In this regard, electrical geophysical prospecting methods are often included in the complex of prospecting and exploration works, before which it is necessary to justify the application of the chosen method for solving the problems by performing numerical modelling. Aim. To substantiate the use of electrical resistivity tomography for the search for groundwater, taking into account complicating factors, including perennially frozen rocks, taliks, and fault zone, by numerical modelling. Objects. Geological environment represented by Quaternary system rocks and permafrost rocks of Cretaceous sediments of the Zazinskaya intermontane area, fault zone, talik zones. Methods. Solution of the direct problem, solution of the inverse problem, ground geophysical surveys using electrical resistivity tomography. Results. Based on the performed numerical modelling, it is shown that the use of electrical resistivity tomography is expedient when searching for groundwater in the area characterized by various factors: permafrost, talik, and a fault zone. Based on the results of solving direct and inverse problems of electrical survey, using field works performed in 2020 in the Eravninsky district of the Republic of Buryatia as an example, it is shown that pole-dipole arrays in electric resistivity survey with electrode distance of 5 m, successfully confirmed by drilling operations, allow us reliably delineate potential zones of water inflow. These zones, characterized by low values of electrical resistivity, in this area, are related to talik zones, which are powered by heat flow from the bowels of the earth.

In this article, we present two inertial modifications of regularized algorithms for the split variational inclusion problem (SVIP, for short) in real Hilbert spaces (RHSs). When the circumstances are right, strong convergence theorems are demonstrated. The major findings are used to solve the split minimization, split common fixed point problem (SCFPP), split minimization problem (SMP), and split feasibility problems (SFP) in applications. The proposed algorithms are contrasted with a number of other existing algorithms in the literature in order to test their numerical performances. Finally, the computer tests demonstrate that the suggested algorithms outperform alternative strategies in terms of speed and efficiency.

A reduced-dimension (RD) method based on the proper orthogonal decomposition (POD) technology and the linearized Crank–Nicolson mixed finite element (CNMFE) scheme for solving the 2D nonlinear extended Fisher–Kolmogorov (EFK) equation is proposed. The method reduces CPU runtime and error accumulation by reducing the dimension of the unknown CNMFE solution coefficient vectors. For this purpose, the CNMFE scheme of the above EFK equation is established, and the uniqueness, stability and convergence of the CNMFE solutions are discussed. Subsequently, the matrix-based RDCNMFE scheme is derived by applying the POD method. Furthermore, the uniqueness, stability and error estimates of the linearized RDCNMFE solution are proved. Finally, numerical experiments are carried out to validate the theoretical findings. In addition, we contrast the RDCNMFE method with the CNMFE method, highlighting the advantages of the dimensionality reduction method.

The properties of sinc approximations are considered. Previously used classical sinc-approximations provide poor approximation quality, while a new operator generalizing sinc approximations yields better results. The numerical implementation of an experiment is presented in plots. [ABSTRACT FROM AUTHOR]

The results are presented of the numerical experiments aimed at obtaining detailed and reliable data on the mean and turbulent characteristics of the asymmetric curved turbulent wake behind a flat plate (FP) subjected to an adverse pressure gradient (APG). The computations are performed for the model wake configuration designed earlier by the authors with the use of the scale-resolving zonal Reynolds-averaged Navier–Stokes-improved delayed detached-eddy simulation (RANS-IDDES) approach to represent turbulence. The reliability of the obtained results is confirmed by the grid independence of the obtained solutions, and a comparison of these results with the corresponding results of computations performed with the use of various semiempirical RANS models indicates the insufficient accuracy of the latter and the need for their further improvement. [ABSTRACT FROM AUTHOR]

The properties of sinc approximations are considered. Previously used classical sinc-approximations provide poor approximation quality, while a new operator generalizing sinc approximations yields better results. The numerical implementation of an experiment is presented in plots. [ABSTRACT FROM AUTHOR]

In this article, we present two inertial modifications of regularized algorithms for the split variational inclusion problem (SVIP, for short) in real Hilbert spaces (RHSs). When the circumstances are right, strong convergence theorems are demonstrated. The major findings are used to solve the split minimization, split common fixed point problem (SCFPP), split minimization problem (SMP), and split feasibility problems (SFP) in applications. The proposed algorithms are contrasted with a number of other existing algorithms in the literature in order to test their numerical performances. Finally, the computer tests demonstrate that the suggested algorithms outperform alternative strategies in terms of speed and efficiency. [ABSTRACT FROM AUTHOR]

The authors overview spatial static boundary-value problems of mathematical physics for a layer. The problem for a layer with a non-circular cylindrical through hole is solved using the singular integral equations (SIE) method. A new mathematical model has been constructed; namely, a new method based on a system of three SIEs has been developed and tested numerically. As a result of a high-precision numerical study, it was found that as the thickness of the layer increases, the relative circumferential stress grows. In the case of a circular hole, the maximum relative circumferential stress shifts inside from the ends. [ABSTRACT FROM AUTHOR]

In this paper, a modified two-grid algorithm based on block-centred finite difference method is developed for the fourth-order nonlinear extended Fisher–Kolmogorov equation. To further improve the computational efficiency, an effective second-order accurate backward difference formula is considered. The modified two-grid method based on Newton iteration is constructed to linearize the nonlinear system. The method solves a miniature nonlinear system on a coarse grid accompanying a larger time step to get the numerical solution, then computes a linear system constructed by the previous result with the Taylor expansion on a fine grid accompanying a smaller time step to get the correct numerical solution. Theoretical analysis shows that the modified two-grid algorithm can achieve second-order convergence accuracy both in time and space domain. Several numerical experiments are provided to verify the theoretical result and the high efficiency of this approach. The practical problem illustrates the actual applicable value of the algorithm. [ABSTRACT FROM AUTHOR]

Increasingly often, due to the high sensitivity level of diagnostic systems, they are also sensitive to the occurrence of a significant number of false alarms. In particular, in structural health monitoring (SHM), the problem of optimal sensor placement (OSP) is appearing due to the need to reach a balance between performance and cost of the diagnostic system. The applied approach of considering nondominated solutions allows for adaption of the system parameters to the user's expectations, treating this optimization problem as multi-objective. For this purpose, the NSGA-II algorithm was selected for the determination of an optimal set of parameters in the OSP problem for the detection of delamination in composite structures. The objectives comprise minimization of type-I and type-II errors, and number of sensors to be placed. The advantage of the proposed approach is that it is based on experimental data from the healthy structure, whereas all cases with a presence of delamination were acquired from numerical experiments. This makes it possible to develop a customized SHM system for the arbitrary location of damage. [ABSTRACT FROM AUTHOR]

Spatial static boundary-value problems of mathematical physics for a layer with a non-circular cylindrical through hole have hardly been solved using the method of singular integral equations (SIE) despite the fact that numerous fundamental theoretical issues have been developed. Methods for the calculation of spectral characteristics are also absent. The paper provides an overview of the methods for solving these problems. A new mathematical model has been constructed, and a new method based on a system of three SIEs has been developed and tested numerically. As a result of a high-precision numerical study, it was found that with an increase in the thickness of the layer, an increase in the relative circumferential stress occurs. In the case of a circular hole, a shift of the maximum relative circumferential stress from the ends to the depth of the layer is observed. In the case of an elliptical hole, with a decrease in one of the radii, an increase in the relative circumferential stress is also observed. [ABSTRACT FROM AUTHOR]

A mathematical model of a technical RF inductively coupled plasma is presented. Results of a numerical experiment are reported in which key parameters for a system with five coils and a coupled power of 60 kW at the generator frequency 1.76 MHz were assessed. The distributions of temperature, pressure, flow rate, and current and magnetic flux density are displayed. The numerical experiment presented was carried out using the Magnetic Fields, Laminar Flow, and Heat Transfer modules of COMSOL Multiphysics®. [ABSTRACT FROM AUTHOR]

We established a new conjugate gradient method with an efficient restart direction for solving large scale unconstrained optimization problems. The modified method was proposed under the Polak-Ribière-Polyak conjugate gradient method. Under the strong Wolfe line search, the search direction of the new method was sufficiently descent and its global convergence property could be proved. Compared with other methods having good numerical performances, numerical experiments and image restorations showed that the modified method was more effective. [ABSTRACT FROM AUTHOR]

This article addresses the critical issue of harmful impurity dispersion in industrial facility atmospheres, considering point sources and factoring in photochemical changes. Conjugate equations are employed to assimilate pollutant data into the transfer equations' right side. Boundary conditions derive from global models like weather research and forecasting (WRF) and system for integrated modeling of atmospheric composition (SILAM), customized for the unique characteristics of an industrial city's pollutants. To encompass anthropogenic heat sources and surface heterogeneity, the model incorporates differential schemes for the atmospheric boundary layer, transport equations, and impurity transformation equations. Parameters for photochemical transformations, varying with weather and time of day, are derived from Ust-Kamenogorsk. A cloud-based geoinformation system (GIS) is developed for monitoring and forecasting air pollution. It assimilates data sources and accounts for photochemical transformations, enabling visualization of diverse weather and environmental scenarios. The article presents numerical modeling results of impurity spread and transformation influenced by mesometeorological processes, topography, and water resources within a specific city. [ABSTRACT FROM AUTHOR]

Organizational innovation performance is considered to be the key to maintaining competitiveness and achieving sustainable development in modern enterprises. Deviant innovation refers to that employees improve their working methods without the permission of the organization, break through the constraints of existing rules and achieve high performance. Additionally, Deviant innovation behavior can also stimulate the enthusiasm of other members of the organization. In order to study the evolutionary game rules of strategic interaction between enterprises and employees in the process of deviant innovation, this paper constructs a 2*2 asymmetric payoff matrix, and uses numerical simulation to show the influence of different values of decision parameters and changes of initial conditions on the evolutionary results. The research reveals that the interaction game between employees’ deviant innovation behavior and enterprise enhancement of organizational innovation performance is a complex and significant topic. It is found that when enterprises actively improve organizational innovation performance and employees implement deviant innovation behavior, both sides engage in positive game interactions, maximizing enterprise benefits. However, when enterprises passively enhance organizational innovation performance but employees engage in deviant innovation behavior, it may lead to conflicts between the two parties. The research findings provide relevant strategies for employees to correctly implement deviant innovation behavior and for enterprises to enhance organizational innovation performance.

Purpose: to study the distribution of pore pressure under an underground dam located in a mountain valley for the atmospheric precipitation accumulation, while analyzing the effect of water levels in headwater and tailwater. At the same time, the factors of influence varied in the range: the water level in headwater from minus 8.2 to minus 1.2; water level in tailwater from minus 7.9 to minus 6.7. Materials and methods. The study of a complex system was carried out in two stages. At the first stage, the pore pressure under the underground dam, responsible for the seepage under it, was calculated using the finite element method based on the Midas GTX NX software package, which has the ability to take into account the complex joint operation of the underground dam and the soil mass. At the second stage, the resulting array of numbers, which reflects the physical processes occuring when the response function, which is taken as the pore pressure under the underground dam, is affected by disturbances, for which the water levels in headwater and tailwater of the dam are taken, was subjected to digital analysis. Results. The range of pore pressure values at the maximum headwater levels is 31.72 % over the entire range of tailwater levels. For the average levels of the headwater, the range of pore pressure values is 32.70 %, and for the minimum levels of the headwater, the range of pore pressure values is 39.41 %, also in the entire range of changes at the tailwater levels. Thus, the lower the headwater level, the greater the impact on the pore pressure of the tailwater level. Conclusions: with a change in the studied range of water levels in headwater or tailwater of the dam, i.e. factors of influence, with a decrease in the values of the impact factors, the degree of their influence on the pore pressure under the underground dam decreases, and with growth – increases, and it occurs almost linear.

Gear pumps are hydraulic machines capable of transferring energy and performing work in pumping fluid. This study presents an analysis of the hydrodynamic model of an external multiple gear pump in order to analyze the fluid flow in combinations of single and different viscosities at the same and different pressures and speeds. Solidworks Flow Simulation 2016 was used to analyze fluid flow. When the radius of the rounding on the collector inner surface is increased from 3 to 15 mm, the pressure drop decreases by 13%. When the radius of the manifold is 3 mm, cavitations are observed. With a liquid distribution system with four input ports and one outlet port in the top cover, the gear pump can handle liquids of viscosity classes 5 to 10. The speed should not exceed 1200 rpm if the liquid has a kinematic viscosity of 10 cSt. The pressure drop and velocity distribution of the liquid in the pressure and suction lines are the same. When the speed changes from 400 to 1200 rpm, the pressure drop increases five times, and the velocity increases three times. At a constant speed of 1000 rpm and an inlet pressure of 10 MPa but with different viscosities, the pressure drop decreases 8 times, and the speed increases 1.5 times. When the inlet pressure is 6 to 24 MPa, with constant speed and the same viscosity, the pressure drop and fluid velocity practically do not change. The dependence of pressure drop on the number of revolutions and radius of the rounding of the inner surface of the collector is statistically significant.

Abstract. Objective. The aim of the study is to develop a methodology for calculating a two-cascade thermoelectric system (TPS) for local hypothermia, as well as a theoretical analysis of its operation.Method. The model is built on the basis of solving three problems, consisting in determining the parameters of a two-stage thermoelectric module (TEM), thermophysical characteristics of the interface system with a biological object, and heat removal for cooling the hot junctions of the thermomodule.Results. According to the calculation model, the TES was calculated for local hypothermia of soft tissues in the treatment of their inflammation and infectious formations, developed in the laboratory of semiconductor thermoelectric devices and devices of the Daghestan State Technical University. Graphs of the dependence of the change in the cooling capacity of the TEM, the coefficient of performance, the supply voltage on the temperature difference between the junctions for various values of the supply current, as well as the dependence of the voltage on the TEM on the magnitude of the supply current at various values of the temperature difference between the junctions, the change in temperature by cold junction and TEM power from the supply current. The graphs are calculated at a hot junction temperature of 300 K.Conclusion. As a result of the calculations, it was found that the TV-2-(127-127)-1.15 TEM selected as a result of the calculation will have the following characteristics: an operating power range of 8-10 W with an average temperature difference between the junctions of 65 K, the supply current is 4 .4-5.8 A with a power consumption of 45-85 W, the coefficient of performance is 0.2-0.5.

The issues of ensuring the reliability of the finite element models (FEM) of the fuselage in the hatch cutout zone are considered at the early aircraft design stages. The purpose and tasks of research are formulated. To assess the reliability of mathematical models, the objects with standards were selected. The methods of experimental research and measuring instruments are discussed. The results of a comparative analysis of the numerical experiment with analytical solutions and full-size experiments data are presented. For the validation of FEM structures, the checkable characteristics and types of their verification are determined. The results of this research contain a discussion of the impact of finite element mesh details on a stress concentration factor, an adequacy of modeling the stress and strain field in the vicinity of the cutout and taking into account a nonlinearity in strength calculations of structures with stress concentration. This paper focuses on the analysis of modeling a framed cylindrical shell with a large rectangular cutout, for which full-size tests were conducted by TSAGI researchers. Strains of strong frames, limiting the cutout in a cylindrical shell, shearing and equivalent stress in the skin, normal stresses in stringers at the intersection with the strong frame, displacements of strong frames cross-sections at test points are analyzed. Based on the results of this research, the recommendations for modeling thin-walled fuselage structures in the vicinity of a large cutout, ensuring the performance of calculations with engineering accuracy were formulated.

Purposes This work is conducted to exclude the superimposed effect of natural rock specimen discreteness and multiple stress path conversion in test process on results, and to further investigate the influence mechanism of the confining pressure unloading rate on rock failure and instability. Methods The discrete element method was used to carry out homogeneous numerical specimens under constant axial pressure and two fixed confining pressure unloading rates. The macroscopic and mesoscopic mechanical properties and laws of the specimens under two confining pressure unloading rates are compared and discussed. Findings The results show that the macroscopic and mesoscopic fracture distributions have certain similarity and regularity under the two conditions, the load-bearing strength of the specimen in slow confining pressure unloading rate is higher than that in fast condition, and the local fracture distribution density at the fast unloading condition is relatively larger. The axial and confining pressure “falls” and “rises” during the two unloading rate tests, which reflects that the specimens have undergone a multi-stage sudden and progressive failure process. The continuous accumulation of local damage leads to the overall instability of the specimens. The number of tensile fractures under the two unloading rates is significantly larger than that of shear fractures, and the growth rate of tensile fractures is greater than that of shear fractures. The slow unloading condition relatively fully mobilized the local bearing capacity of the specimen and improved the ultimate bearing capacity of the specimen. Conclusions Under the two conditions, the distribution of fractures composed of more than 20 AE events is the most uneven. With the increase of AE event numbers creating each fracture, the overall seismic magnitude increases gradually, and the overall energy release during the fast unloading process to form fractures becomes relatively higher, while slow unloading transfers stress at a relatively slow rate, resulting in a relatively lower, smooths, and uniform energy release during fracture formation.

This article presents a study based on a series of numerical experiments. It demonstrates the possibility of reducing fluctuations in the calculation of reactivity using the second Bernoulli number based on the approximation of the Euler-Maclaurin formula. This approach requires knowledge of the first three derivatives, which are implemented progressively. The fluctuations are assumed to occur around an average value of the neutron density with a Gaussian distribution. Jitter reduction is performed with a first-order delayed low-pass filter for different forms of neutron population density, with different time steps and with different filter constants. The numerical results show that the method can be used as a digital reactivity meter.

The paper presents tasks and approaches to their solutions in assessing vibration strength and dynamic safety of marine reactor equipment (for example: pumps, control driven rod mechanisms). The topicality of this work is determined by the experience of operating nuclear power plants. Development of digital computation models and computational analysis allowed us to exclude experimental validation of control driven rod mechanisms seismic resistance. A digital computational model was developed for validating the dynamic safety and life time of the seal pot of the reactor facility main circulation pump. The model included the main circulation pump and the framework of the reactor facility. Computational and experimental analysis of the vibration state of the control and protection system drives was also carried out.

Split-step quintic B-spline collocation (SS5BC) methods are constructed for nonlinear Schrödinger equations in one, two and three dimensions in this paper. For high dimensions, new notations are introduced, which make the schemes more concise and achievable. The solvability, conservation and linear stability are discussed for the proposed methods. Numerical tests are carried out, and the present schemes are numerically verified to be convergent with second-order in time and fourth-order in space. The conserved quantity is also computed which agrees with the exact one. And solitary waves in one, two and three dimensions are simulated numerically which coincide with the exact ones. The SS5BC scheme is compared with the split-step cubic B-spline collocation (SS3BC) method in the numerical tests, and the former scheme is more efficient than the later one. Finally, the SS5BC scheme is also applied to compute Bose-Einstein condensates.

In crank presses, an important role is played by the presence of actuators with dwell, in which, with continuous movement of the input links, the output working link remains stationary at some part of the work. The use of a high-class structural group (fourth class) expands the functionality of the crank press, including it can ensure the link dwell of the working link on a given section of movement during the required period of time. As a result of the conducted numerical research, four variants of actuators of the crank knee press were designed. Due to the rational choice of the positions of racks and crosshead guide, the best layout of the dimensions of the press mechanism has been achieved. Changing the coordinates of the racks accordingly allows for designing a mechanism with upper or lower dwells of the working links. The duration of the dwell of the working link (slider) can be adjusted by selecting the distance between the racks with rotational pairs and a crosshead guide of the mechanism. All this is shown on the basis of a numerical experiment based on kinematic analysis. In addition, the proposed structure of the mechanism makes it possible to ensure the exact link dwell, which cannot be achieved due to the well-known knee presses based on the second-class mechanism. [ABSTRACT FROM AUTHOR]