bluuebunny/crossref_metadata_2025_split huggingface dataset:
Research on the impact of aluminium alloys forming technology on the resistance to fatigue
Authors: Zakharchenko K V , Kapustin V I , Larichkin A Yu , Raevskaya G A 
Published: July 2019

Abstract
The research is devoted to the evaluation of the impact of aluminium alloys processing by pressure in creep on the resistance to fatigue. Using the developed accelerated, non-destructive method, the kinetics of the total deformations response (longitudinal and transverse components) during deformation of the sample with increasing loading is considered. In the frames of this method, the limiting stresses are determined, a conservative estimate of the endurance limit for V95 and V-1461 aluminium alloys (analog 7475) (Al-Zn-Mg-Cu) and (analog 2099) (Al-Cu-Li-Zn), respectively, is obtained. Thick plates (40 mm) are molded on the UFP-1M equipment in creep, and surface control is carried out. More than 80% of the plate’s area is molded with a deviation of less than 1 mm from the nominal size. The microstructure of V-1461 alloy is studied before and after forming, and fatigue tests are performed on samples made of molded panels. Analysis of the research results showed that for the V95 and V-1461 alloys, the selected characteristics of the technological process of forming and heat treatment do not impair the fatigue properties of the studied alloys.
Solving a two-dimensional problem of heat wave initiation by a boundary condition specified on a movable manifold
Authors: Kazakov A L , Spevak L F , Nefedova O A 
Published: July 2019

Abstract
A boundary value problem for a nonlinear degenerate parabolic equation is considered for the case of two spatial variables. The boundary condition is specified on a movable manifold a time-varying closed line. A heat wave problem solution is constructed on the basis of the boundary element method. The numerical solution algorithm is based on the change of variables, when the roles of the required function and the radial coordinate of the polar system interchange. The BEM solution of the problem obtained in new symbols enables the zero front of the heat wave to be determined. The further solution of the problem with the known zero front yields a solution to the initial problem. The algorithm is implemented as a program. An exact (generalized self-similar) solution is constructed, whereby the program is tested.
Formation of a cavitation zone behind a rarefaction wave front in a shock-loaded thin layer of a multiphase liquid
Authors: Kedrinskiy V K , Zhuravleva E S 
Published: July 2019

Abstract
The evolution of bubble cavitation behind the front of a converging cylindrical rarefaction wave in distilled water containing micro inhomogeneities is investigated numerically within the framework IKvanW mathematical model. The dynamics of the cavitation zone state is considered in a one-dimensional formulation with cylindrical symmetry. A thin liquid layer bounded by the free surface is loaded by a shock wave generated by a piston coaxial the axis of symmetry. As a result of shock wave reflection from free surface, a rarefaction wave converging toward the axis of symmetry is formed. The influence of the initial size of microbubbles, gas phase concentration, and parameters of shock wave loading on the dynamics offormation of the cavitation zone and its growth in the course of rarefaction wave focusing is analyzed.
Modeling of supersonic gas flows in radial nozzles
Authors: Kiselev S P , Kiselev V P , Zaikovskii V N 
Published: July 2019

Abstract
In the present paper, we report on the results of a study of supersonic gas flows in a radial nozzle. The pressurized gas is supplied into a circular channel, from which it then flows into the gap between two parallel disks (radial nozzle). It is shown that the structure of the jet ejected into ambient space substantially depends on the friction force acting on the gas flow from the side of the disks. The force of friction leads to a considerable decrease of the velocity of the supersonic jet, which acquires a fan-shaped form instead of being barrel-shaped. The numerical results proved to be in good agreement with experimental data.
Mathematical modeling of the generation of acoustic waves in a two-channel system
Authors: Kravchenko A S , Zhilin A A 
Published: July 2019

Abstract
The purpose of this study is to determine the influence of the diameter of a subsonic conical nozzle on the generation of acoustic waves in a two-channel system. Three-dimensional numerical simulation of flow in the duct of an actual device was performed. A complete picture of the flow generated in the acoustic-convective drying system of the Institute of Theoretical and Applied Mechanics, SB RAS, was obtained. The results of the study show that to maintain the amplitude-frequency characteristics of the workflow with increasing diameter of the subsonic conical nozzle, it is necessary to reduce the settling chamber pressure. The numerically simulated amplitude-frequency characteristics of the acoustic flow generated in the working section of the drying system are in satisfactory agreement with the results of physical experiments.
Reconstruction of tsunami source by a part of wave time series
Authors: Lavrentiev M , Marchuk An , Kuzakov D 
Published: July 2019

Abstract
Determination of the initial water surface displacement at tsunami source is an essential part for most of tsunami warning systems. Every additional minute is important for safety measures in case of a near field event. We propose to determine initial sea surface displacement at tsunami source by processing only a part of a measured wave profile – time series. The measured wave profile is an input data for initial wave shape determination algorithm. As is established, even a part of wave profile is enough to determine the wave key parameters with an appropriate precision. This paper provides numerical experiments that allow to determine the length of the necessary part of the measured profile. The results will help decreasing total time spent on tsunami forecast.
The modelling of transportation process in porous media: transportation through channels
Authors: Maryshev B S , Klimenko L S 
Published: July 2019

Abstract
The paper is devoted to the study of solute transport through the channels. Since the fluid velocity in the present system is very heterogeneous, the transfer of solute particles has nontrivial properties. Particles of solute hold near the walls, which leads to the time lag of a large number of particles from the main mass flow. As a result, the transport process may become anomalous. Such flows are possible in a porous medium, where the anomalous transport is frequently observed and confirmed by numerous experiments. Usually, such transport is associated with sticking of particles on the pore walls. In the present paper, we had shown that the slow flow in a viscous boundary layer itself can be a reason for the anomalous transport.
On Hiemenz flow of Maxwell incompressible viscoelastic medium
Authors: Moshkin N P 
Published: July 2019

Abstract
Steady axisymmetric flow of a viscoelastic incompressible fluid near the critical point of the plane surface is considered. Model of Maxwellian fluid with upper convected derivative in the rheological constitutive law is used. Velocity and extra stresses field are discussed for various Weissenberg numbers. The subclass of solutions in a stationary case is completely described. The asymptotic solutions for small Weissenberg numbers are compared to the solutions of the complete nonlinear problem. It is found that the fluid elasticity decreases the boundary layer thickness.
On integration of the system of MHD equations modeling wave processes in a rotating liquid with arbitrary magnetic Reynolds number
Authors: Peregudin Sergey , Peregudina Elina , Kholodova Svetlana 
Published: July 2019

Abstract
The paper is concerned with the dynamics of large-scale wave processes in a rotating layer of inviscid conducting incompressible liquid of variable depth. The problem is modelled as a system of partial differential equations with necessary boundary conditions. With the help of auxiliary functions, the above system of partial differential magnetohydrodynamic equations is reduced to a single scalar partial differential equation. An exact analytic solution of the small perturbation problem is obtained. It is shown that if the external magnetic field is parallel to the axis of rotation of the layer, then the magnetic field decays for finite values of the magnetic Reynolds number.
Nonlocal integro-differential problems of multi-dimensional wave processes
Authors: Popov N S 
Published: July 2019

Abstract
Nonlocal boundary-value problems for one-dimensional parabolic second-order equations with integral conditions on the lateral boundary are considered in the articles by A.I. Kozhanov. Higher-dimensional integro–differential equations of higher order with integral conditions on the lateral boundary were not studied earlier. The existence and uniqueness theorems of regular solutions are proven. The method of regularization and the method of continuation in a parameter are employed to establish solvability. In the present article we study integro-differential equations with integral conditions on the lateral boundary and prove existence theorems for regular solutions.
Nonlinear systems’ equilibrium points: branching, blow-up and stability
Authors: Sidorov Nikolai , Sidorov Denis , Li Yong 
Published: July 2019

Abstract
This article considers the nonlinear dynamic model formulated as the system of differential and operator equations. This system is assumed to enjoy an equilibrium point. The Cauchy problem with the initial condition with respect to one of the desired functions is formulated. The second function controls the corresponding nonlinear dynamic process. The sufficient conditions of the global classical solution’s existence and stabilisation at infinity to the equilibrium point are formulated. The solution can be constructed by the method of successive approximations. If the conditions of the main theorem are not satisfied, then several solutions may exist. Some solutions can blow-up in a finite time, while others stabilise to an equilibrium point. The special case of considered dynamic models are differential-algebraic equations which model various nonlinear phenomena in circuit analysis, power systems, chemical processes and many other processes.
Movement of external load over free surface of fluid in the ice channel
Authors: Sturova I V , Tkacheva L A 
Published: July 2019

Abstract
The solution of a steady three-dimensional problem for the wave disturbances induced by a local pressure distribution moving with uniform speed on open water lead between two semi-infinite floating ice sheets (ice channel) is presented. This external load simulates an air-cushion vehicle (ACV). The problem is formulated within the linear hydroelastic theory. The fluid is assumed to be inviscid and incompressible and its motion is potential. The ice sheets are treated as viscoelastic thin plates. The solution of this problem is constructed using the Fourier transforms and the Wiener-Hopf technique. The displacements of free surface and ice sheets are determined as well as strains in ice and wave resistance acting on ACV at various speeds of its movement: subcritical and supercritical ones relative to the minimum phase velocity of flexural-gravity waves (FGW) in fluid under an ice cover. Special attention is paid to the characteristics of edge waves. It is shown that for some values of load speed, ice thickness and external pressure, ice fracture near the edge is possible.
Nonlinear self-adjointness and conservation laws for some equation systems of two-phase media
Authors: Fedorov V E 
Published: July 2019

Abstract
The T B Anderson — R Jackson system of equations with the Stokes regime of wrapping around is considered, which describes in the isothermal case the dynamics of a mixture of gas and fine solid particles, taking into account the difference in velocities and the presence of the own particle phase pressure. The system includes the equations for the conservation of mass and momentum, written for each phase and supplemented by equations of state. The aim of the paper is the search of conservation laws for the system by means of N Kh Ibragimov’s nonlinear self-adjointness method. For this purpose it was found a substitutions family, which corresponds to the nonlinear self-adjointness of equations of the T B Anderson — R Jackson system. Using this result and known symmetries of the equations system, the series of conservation laws were derived. It is noted that the analogous results are valid for the Kh A Rakhmatulin system of equations of a mixture dynamics with one pressure.
Representation of solutions of boundary value problems for nonlinear evolution equations by special series with recurrently calculated coefficients
Authors: Filimonov M Yu 
Published: July 2019

Abstract
One of the analytical methods of presenting solutions of nonlinear partial differential equations is the method of special series in powers of specially selected functions called basic functions. The coefficients of such series are found successively as solutions of linear differential equations. The basic functions can also contain arbitrary functions. By using such functional arbitrariness allows in some cases, to prove the global convergence of the corresponding constructed series, and also allows us to prove the solvability of the boundary value problem for the Korteweg-de Vries equation. In the paper for a nonlinear wave equation a theorem on the possibility of satisfying a given boundary condition using an arbitrary function contained in the basic function is proved.
On stability of radial collapse of cylindrical shell filled with viscous incompressible fluid
Authors: Fursova D A , Gubarev Yu G 
Published: July 2019

Abstract
We study nonlinear stability of radial collapse of a cylindrical shell filled with a viscous incompressible fluid homogeneous in density. We have made the following assumptions: 1) there is a vacuum inside the shell, 2) there is the layer of compressed polytropic gas outside the shell, the gas serves as a product of instant detonation and causes nonzero constant pressure on the outer surface of the shell, 3) there is a vacuum beyond the layer of gas. By the direct Lyapunov method, we state the absolute stability of radial collapse of the viscous cylindrical shell relative to finite disturbances of the same type of symmetry. Namely, we construct a Lyapunov function satisfying all conditions of the Lyapunov first theorem (stability theorem) regardless of radial collapse mode. Thus, we confirm the Trishin hypothesis and prove that cumulation of the fluid kinetic energy during the radial collapse of the cylindrical shell near its geometric axis never originates.
The least squares collocation method for the biharmonic equation in irregular and multiply-connected domains
Authors: Shapeev Vasily , Golushko Sergey , Bryndin Luka , Belyaev Vasily 
Published: July 2019

Abstract
This paper reports new h-and p-versions of the least squares collocation method of high-order accuracy proposed and implemented for solving boundary value problems for the biharmonic equation in irregular and multiply-connected domains. This paper shows that approximate solutions obtained by the least squares collocation method converge with high order and agree with analytical solutions of test problems with high degree of accuracy. There has been a comparison made for the results achieved in this study and results of other authors who used finite difference and spectral methods.
On the application of SPH to solid mechanics
Authors: Shutov Alexey , Klyuchantsev Vladislav 
Published: July 2019

Abstract
We analyze the applicability of the smooth particle hydrodynamics (SPH) to the solution of boundary value problems involving large deformation of solids. The main focus is set on such issues as the reduction of artificial edge effects by implementing corrected kernels and their gradients, accurate and efficient computation of the deformation gradient tensor, evaluation of the internal forces from the given stress field. For demonstration purposes, a hyperelastic body of neo-Hookean type and a visco-elastic body of Maxwell type are considered; the formulation of the Maxwell material is based on the approach of Simo and Miehe (1992). For the implementation of constitutive relations efficient and robust numerical schemes are used. A solution for a series of test problems is presented. The performance of the implemented algorithms is assessed by checking the preservation of the total energy of the system. As a result, a functional combination of SPH-techniques is identified, which is suitable for problems involving large strains, rotations and displacements coupled to inelastic material behaviour. The accuracy of the SPH-computations is assessed using nonlinear FEM as a benchmark.
Study of the Effect of River Basin Morphology Change on Threshold Parameters in Cimahi Flood Early Warning System
Authors: Budi Safarina Ariani , Karnisah Iin , Sena Permana Ade 
Published: July 2019

Abstract
Flood early warning systems are used for flood disaster preparedness to reduce disaster risks. The problem is damage of water level sensor due to aggradation which also results in river capacity reduced. The purpose of this research is to determine the effect of river basin morphology change on threshold parameters in flood early warning system. Measured hydraulic parameters are flow depth, flow velocity, and riverbed slope. Land cover was conducted using Cimahi river basin land use map to determine runoff coefficient. Rainfall-runoff model used is the Deconvolution Software program to determine unit hydrographs. Results of this study indicate that morphological changes of watershed significantly influence threshold parameters. A 0.5 m rise in river bed can reduce river capacity by 41.8% and narrowing of 16 m-wide river border dropped river capacity from 730 m3/s to 95.2 m3/s. An increase of 17 % runoff coefficient, increased direct runoff by 17%. Reducing this river capacity makes threshold parameters in flood early warning system invalid causing flood events cannot be detected earlier by the system.
Factors Affecting Post-Disaster Housing Reconstruction on Preconstruction Stage in Pidie Jaya Regency Indonesia
Authors: Malahayati Nurul , Munirwansyah  , Afifuddin Mochammad , Syamsidik  
Published: July 2019

Abstract
Pidie Jaya regency is one of the regencies located in Aceh Province, Indonesia. On 7 December 2016 an earthquake rocked the Pidie Jaya with a magnitude of 6.5 on the Richter scale on coordinates 5.25 ° North and 96.24 ° East latitude with an estimated in-depth of 15 km. The impact of the disaster caused a lot of damage to infrastructure, especially public housing. The Reconstruction of disaster victim housing in Pidie Jaya District uses community-based methods designed with a community organizing strategy. In the early stages of reconstruction many problems arose between the government, the management consultant, and the community beneficiaries resulting in a delay in the construction housing implementation. This period is called preconstruction, where the activities carried out focused on the preparatory activities to rebuild housing of disaster victims. Questionnaire surveys and interviews were given to stakeholders from the government, the management consultants and the community involved in housing reconstruction. Data were analyzed using statistical software. The results of this study have identified that the dominant factors influencing implementation in pre-construction are starting at the moment (1) recruitment of facilitators; (2) program training for the community; (3) formation of community organizations; (4) program socialization and coordination; (5) inventory, verification and validation of damage data; (6) design and funding. The dominant factors in the pre-construction are interrelated with each other because the problems that occur at the beginning of the pre-construction period, result in delays in the implementation of the construction of the houses. Identifying specific factors that create problems that affect the success of the project in this study is the basis for practitioners, stakeholders and the community in managing a post-disaster housing project, so that it can anticipate the occurrence of similar things in the implementation of reconstruction in the future.
Comparing Asian Gypsy Moth [Lymantria dispar asiatica (Lepidoptera: Erebidae) and L. dispar japonica] Trap Data From East Asian Ports With Lab Parameterized Phenology Models: New Tools and Questions
Authors: Trotter R Talbot , Limbu Samita , Hoover Kelli , Nadel Hannah , Keena Melody A 
Published: July 2019

Abstract
Management of the European gypsy moth [Lymantria dispar dispar (Linnaeus)] in North America has benefited from more than a century of research. The East Asian strains of the gypsy moth, however, bring new challenges including multiple subspecies (Lymantria dispar asiatica Vnukovskij and Lymantria dispar japonica Motschulsky), broad distributions across heterogeneous habitats, and a lack of data on the variation in the phenology of source populations, which may affect risk. To address these issues, published phenology parameters for eight populations of Asian gypsy moth were used to develop eight strain-specific agent-based phenological models. These models were applied to 47 ports in East Asia where the Asian gypsy moth is native, and output was compared with available trap data to assess the role of interpopulation variation in phenological parameters in predicting moth flight among varied locations, assess variation in the performance of models among years, and assess the importance of modeling phenology using parameters from a ‘local’ moth population. Variation in phenological parameters among the eight populations yielded variation in predicted flight times among the 47 ports analyzed, and the use of ‘local’ populations did not generally improve model fit. Model accuracy varied substantially among ports and among years within some ports. The larva-to-adult agent-based models described here have utility in estimating flight periods for some ports in their current form, but variation in model quality across the landscape suggests that there is potential for unsampled and unparameterized moth populations and factors that remain to be quantified.
Rapid Diagnosis of Tuberculosis Meningitis by Detecting Mycobacterium tuberculosis Cell-Free DNA in Cerebrospinal Fluid
Authors: Li Xuelian , Du Weili , Wang Yuxuan , Liu Zichen , Li Kun , Chen Hongmei , Liu Rongmei , Ma Liping , Zhang Liqun , Dong Yujie , Che Nanying , Gao Mengqiu 
Published: July 2019

Abstract

Objectives
Tuberculosis meningitis (TBM) is one of the most severe forms of tuberculosis. However, TBM diagnosis is quite challenging due to nonspecific clinical presentation and the paucity of the pathogen in cerebrospinal fluid (CSF) samples. In this study, we report a new method for detecting cell-free Mycobacterium tuberculosis DNA (cf-TB) in CSF and evaluate its clinical value for TBM diagnosis.

Methods
Of 68 patients prospectively recruited, 46 were diagnosed as having TBM and 22 as non-TBM. We compared the cf-TB method with CSF smear microscopy, mycobacterial culture, and the Xpert MTB/RIF assay (Xpert) using the consensus case definition for TBM proposed in 2009 as a reference standard.

Results
The sensitivity of the cf-TB test was 56.5% (26/46) in patients with TBM, and it was significantly higher than other methods: microscopy (2.2%, 1/46; P &lt; .001), mycobacterial culture (13.0%, 6/46; P &lt; .001), and Xpert (23.9%, 11/46; P = .001). For specificity, none of the four methods reported false-positive results in the non-TBM group.

Conclusions
The new method detecting cell-free M tuberculosis DNA in CSF is rapid and accurate for diagnosis of TBM and easily incorporated into regular laboratory tests.