bluuebunny/crossref_metadata_2025_split huggingface dataset:
Estimation of the contribution of geophysical perturbations to the Earth pole oscillatory process at the precession frequency of the lunar orbit
Authors: Krylov S S , Perepelkin V V , Filippova A S 
Published: September 2020

Abstract
The contribution of the main geophysical perturbations (atmospheric and oceanic) to the oscillatory process in phase with the precession of the lunar orbit is investigated. The solutions for the differential equations of Earth pole motion are obtained, taking into account the atmospheric angular moment and the oceanic angular momentum, and the combination harmonics associated with the oscillatory process under consideration are identified. It is shown that the harmonics found are partially caused by fluctuations in the mobile media of the atmosphere and ocean.
Fluid flow modeling in solid rock fractures
Authors: Cherednichenko I N 
Published: September 2020

Abstract
This paper considers the solution of the problem of modeling fluid flows occurring while filling solid rock fractures with fluid under pressure. For the mathematical modeling of the solid rock, real data of the rock core sample density was used, obtained in the imaging process of Synchrotron radiation X-ray tomographic microscopy. A calculation method of computational grid cell effective volume, which takes into account rock permeability parameter and is based on tomographic data, is described. To simulate the fluid behavior the modified finite volume method, widely used in hydrodynamics, was applied. Its modification is described for calculating the medium with a variable permeability. The results of numerical experiments are presented.
Solving equations of 3D elasticity for orthotropic bodies
Authors: Revenko V P , Bakulin V N 
Published: September 2020

Abstract
A mathematical model of the three-dimensional orthotropic body was used. A technique has been developed for integrating equilibrium equations in displacements that describe the stress state of orthotropic materials. We find the solution of equilibrium equations in displacements for orthotropic bodies. The expression of displacements, strains and stresses is obtained through the introduced displacement function, which satisfies the sixth-order equation for partial derivatives. We develop the algorithm of the analytical and numerical solutions of boundary value problem for orthotropic rectangular prism. Solution of boundary value problems is reduced to minimize a generalized quadratic form.
Natural convection in horizontal layers with lateral heating at various Rayleigh and Prandtl numbers
Authors: Fedyushkin A I 
Published: September 2020

Abstract
The paper presents the results of numerical solution of the problem of thermal convection of an incompressible liquid in a horizontally elongated layer with lateral heat supply. In this paper the influence of Rayleigh and Prandtl numbers of boundary conditions on the flow structure and on the existence of counter-flows are considered. It is also shown that for laminar convection modes, flows with Prandtl numbers less than 0.01 differ qualitatively from the flow of a liquid with a zero Prandtl number, so the approximation of the zero value of the Prandtl number may not always be correct.
Influence of the nozzle shape on sound generation in a jet-driven Helmholtz oscillator
Authors: Abdrashitov A A , Marfin E A , Plakhova E A 
Published: September 2020

Abstract
The excitation of pressure fluctuations by an air jet in the model of a Helmholtz oscillator, consisting of a cylindrical chamber with a nozzle in the front cover and an outlet opening in the rear one was studied. The influence of the shape of the nozzle in combination with the length of the chamber and the diameter of the outlet opening was considered. The amplitude-frequency spectra when changing the configuration of the oscillator and the Reynolds number in the allowable range was analyzed. The formation of the reverse flow area in a cylindrical nozzle and its influence on the intensity of the interaction of the jet with the flooded chamber volume are considered. The advantage of a nozzle with a profiled inlet providing a continuous flow in the nozzle and a top-hat profile of velocity at the nozzle exit are determined. The jet-driven Helmholtz oscillator can be used as a downhole emitter for intensifying oil production.
Stabilization of a diffusion flame by a non-stationary electric field
Authors: Tupikin A V , Zamashchikov V V 
Published: September 2020

Abstract
The work is devoted to the study of stabilization of a diffusion torch by an electric field with a time-varying field line configuration. The stability of combustion was studied using this method of stabilization of the flame, namely the position of the ignition points in the presence and absence of an electric field. The experiments proved that the stabilizing effect of an electric field with a time-varying field line configuration is observed when the torch is stabilized near and above the plane of the electrodes. When the direction of electric forces coincides with the direction of the fuel jet, the effect of the field will strengthen the fluctuation of flame.
Numerical study of gas-dynamic and condensation processes in an ejector device used to purify gas-air emissions
Authors: Nazarov V S , Ivanov I E , Kryukov I A 
Published: September 2020

Abstract
The article presents a numerical study of vapor condensation appearing in an ejector. The ejector is a part of a device developed by the authors and used to purify air emissions. The article considers condensation of pure water vapor and condensation of vapor in a mixture of vapor and carrier gas. The system of axisymmetric Navier-Stokes equations and the system of moment equations are considered as a mathematical model for describing two-dimensional non-stationary gas-dynamic processes and processes of phase transitions in the device. The general system of equations is numerically solved using the finite volume method.
Investigation of the Stress-Strain State of the Composite Cylindrical Shell with Rectangular Cutouts
Authors: Bakulin V N 
Published: September 2020

Abstract
An algorithm for constructing a model of effective finite elements of natural curvature for the stress-strain analysis of thin composite cylindrical bending shells, including those weakened by rectangular cutouts, is given. The reliability, accuracy, and model efficiency of the considered finite element and the approximations, which it is based on, are shown by comparison with the most commonly used finite elements. Experimental data for a composite shell with rectangular cutouts are obtained and shown. The computation results obtained using the considered finite element are compared with the experimental data for a composite shell with rectangular cutouts.
Analytical Review of Account Methods and Experimental Approaches to Stress-Strain State Investigation of Structurally-Anisotropic Aircraft Panels Made from Composite Materials
Authors: Gavva L M , Firsanov V V 
Published: September 2020

Abstract
Abstract The different approaches were analyzed to investigate the stress-strain state problems of structurally-anisotropic panels made from composite materials. The classification of mathematical models, analytical methods of calculations, numerical methods of calculations, testing results are presented in this review. New mathematical model relations for the stress-strain state investigation of structurally-anisotropic panels made of composite materials are presented. The primary scientific novelty is the further development of the theory of thin-walled elastic ribs related to the contact problem for the skin and the rib with an improved rib model. A promising area of research is the design of composite aircraft structures in the field of production technologies. We consider the residual thermal stresses and the preliminary tension of the reinforcing fibers with respect to the panel production technology. The stress-strain state problem results in the boundary value problem when solving for the eighth order partial derivative equation in the rectangular field. A computer program package is developed in MATLAB. The computer program package has been utilized for multi-criteria optimization of the design of structurally-anisotropic aircraft composite panels. The results of testing series are presented as the verification of the proposed mathematical model.
Dynamics of initiation of the pseudoshock combustion mode in a constant cross section channel
Authors: Tupikin A V , Tretyakov P K , Kuranov A L , Abashev V M 
Published: September 2020

Abstract
The results of a study on the dynamics of initiation of a pseudo-shock combustion mode in a channel of constant cross section under pulsed action on the flow are presented. Various conditions are considered (kerosene flow rate, change in channel length and working gas in control pulses). Pulsating combustion mode is implemented. It is shown that the reduction of the length of the constant section leads to a decrease in combustion stability. When applying control pulses, two scenarios of the development of disturbances can be implemented: with intensification of combustion and the formation of wave structures, or with attenuation without intensification of combustion. In case of combustion, the motion of the disturbance along the channel can conditionally be divided into two stages: 0 <t <4 ms and t > 4 ms. The duration of the first stage can be interpreted as a delay in the ignition of kerosene; in the second stage, the perturbation velocity relative to the channel walls is almost constant. The use of kerosene (synthesis gas) conversion products in pulses accelerates the transition from diffusion to pseudo-shock combustion, and the rate of disturbance propagation increases by about 2 times.
Low-Power Ion Thrusters. State of Development at Research Institute of Applied Mechanics and Electrodynamics, MAI
Authors: Akhmetzhanov R V , Bogatyi A V , Kashirin D A , Obukhov V A , Popov G A , Svotina V V , Khartov S A 
Published: September 2020

Abstract
This article describes the activities carried out by RIAME MAI in the field of low-power ion thrusters in 2010-2020. The results of study of a laboratory model of low power RIT using a different shape of GDC are presented. The results of work on creating an experimental model of such RIT with elements of the propulsion system are shown. The article also presents the research on the process of erosion of the accelerating electrode of the RIT - a critical element of the thruster design from the point of view of the lifetime.
Effect of radiation on the contact thermal resistance in vacuum
Authors: Ezhov A D , Bykov L V , Reznik S V 
Published: September 2020

Abstract
The solution to most of the problems of ensuring the operating characteristics of units and assemblies of complex technical objects in a wide range of changes in temperature and mechanical loads is associated with ensuring the conditions of contacting surfaces, i.e. with the solution of the contact problem of determining the thermal and strength state of the connection of parts. This problem is also relevant to objects operated in space in a vacuum, where heat transfer between parts can occur only in contact spots (areas of direct contact of surfaces) due to thermal conductivity or due to radiation in places where there is no direct contact. Obviously, in this case, the total contact thermal resistance consists of the composition of these types of heat transfer, and largely depends on the profile and roughness of the contacting surfaces. An assessment of the effect of reemission on the value of contact thermal resistance when the temperature in the contact zone varies from 200 °C to 800 °C under vacuum conditions can allow a much more accurate prediction of the operational characteristics of the contact pair. In this paper, we compare the effect of reemission on the value of contact thermal resistance under various mechanical stresses.
Applying of the heat wave equation in the study of the movement of an aggressive environment front
Authors: Kuznetsov Evgenii B , Leonov Sergey S 
Published: September 2020

Abstract
The article investigates the problem of diffusion of an aggressive environment into a material of construction. This problem is especially relevant when the penetration of an aggressive environment into the structural elements of nuclear installations is investigated. For modeling the diffusion process, we use a hyperbolic wave equation describing the motion of a heat wave. Using the Fourier method, an analytical solution is obtained. An example illustrates the solution of the problem of hydrogen diffusion into a long, thin rectangular cross-section iron rod.
Numerical solving of initial value problems for ordinary differential equations with internal limiting singular points
Authors: Ivannikov A I , Kuznetsov E B , Leonov S S 
Published: September 2020

Abstract
In the present paper, we investigate the numerical methods for solving initial value problems for systems of nonlinear ordinary differential equations with several limiting singular points. Similar tasks have great practical importance in such areas as hydrodynamics, chemical kinetics, combustion theory, computational geometry, and nuclear reactors. However, the exact solution may be constructed to nonlinear initial value problems only in exceptional cases. Numerical methods also do not give the desired result. Explicit methods make it possible to obtain a solution only if there is one limiting singular point on the right boundary of the considered interval of the argument change. Implicit methods also have usage restrictions. They consist of the difficulty or impossibility of overcoming the internal limiting singular points. For solving the considered class of problems, the paper proposes to use the method of solution continuation, which allows passing any limiting singular points effectively. Features of the application of various numerical methods are shown by solving one test initial value problem. The reliability of the obtained numerical results is confirmed by comparison with the finding analytical solution of the considered test problem.
Experimental investigation of the thermal loads upon electrodynamic modification of supersonic flow around axisymmetrical body
Authors: Popov P A , Monakhov N A , Kotov M A , Poniaev S A 
Published: September 2020

Abstract
The results of experimental studies of the magnetohydrodynamic (MHD) effect on the flow around an axisymmetric model of a supersonic nitrogen stream are presented. The magnetic field was created by a solenoid located on the cylindrical part of the model under the influence of a pulsed electric current flowing through the solenoid. A pulsed gas discharge was ignited on the conical surface of the model, acquiring rotation in the solenoidal magnetic field around the model axis. The effect of the magnetic field on the gas-dynamic structure of the flow near the model and the heat flux to its surface were investigated. In the experiments, schlieren pictures,fast photographic scans of the discharge glow were recorded, and heat flux was measured. The effect of a magnetic field on the gasdynamic structure of the flow near the model and the heat load to its surface were found. Also, the dependence of MHD effects on the polarity of external voltage source connecting was found.
Ultradeep Sequencing Analysis of Paroxysmal Nocturnal Hemoglobinuria Clones Detected by Flow Cytometry:PIGMutation in Small PNH Clones
Authors: Jeong Dajeong , Park Hee Sue , Kim Sung-Min , Im Kyongok , Yun Jiwon , Lee Young Eun , Ryu Sohee , Ahn Yong-Oon , Yoon Sung-Soo , Lee Dong Soon 
Published: September 2020

AbstractObjectivesWe aimed to determine whether small paroxysmal nocturnal hemoglobinuria (PNH) clones detected by flow cytometry (FCM) harbor PIG gene mutations with quantitative correlation.MethodsWe analyzed 89 specimens from 63 patients whose PNH clone size was ≥0.1% by FCM. We performed ultradeep sequencing for the PIGA, PIGM, PIGT, and PIGX genes in these specimens.ResultsA strong positive correlation between PNH clone size by FCM and variant allele frequency (VAF) of PIG gene mutation was identified (RBCs: r = 0.77, P &lt; .001; granulocytes: r = 0.68, P &lt; .001). Granulocyte clone size of 2.5% or greater and RBCs 0.4% or greater by FCM always harbored PIG gene mutations. Meanwhile, in patients with clone sizes of less than 2.5% in granulocytes or less than 0.4% in RBCs, PIG gene mutations were present in only 15.9% and 12.2% of cases, respectively. In addition, there was not a statistically significant positive correlation between FCM clone size and VAF or the presence or absence of a PIG mutation.ConclusionsOur results showed that in small PNH clones PIG gene mutations were present in only a small portion without significant correlation to VAF or the presence or absence of a PIG mutation.
Transnational corporations, financialization and community development in West African cocoa
Authors: Amanor Kojo S 
Published: September 2020

Abstract
This article examines the role of financial capital in the cocoa industry of Côte d’Ivoire and Ghana. It argues that the processes of structural adjustment in the 1980s and 1990s brought two important elements into play. Firstly, transnational corporations taking advantage of the opening of global markets to gain control over the cocoa sector, and secondly, financial institutions promoting ‘country platforms’ that encouraged public–private partnerships to mobilize foreign investments and define development objectives. This has led to a distinct pattern of investment, which is intimately connected with governance reforms underpinned by a diverse set of public and private alliances at different levels. The article traces these alliances which have given rise to community development programmes. However, these programmes are underpinned by a drive towards greater intensification of production through the use of inputs supported by credit, which threatens to entangle farmers in debt and lock them into the poverty inherent in the cocoa industry.
Characteristics of patients with coexisting DNAJB9-associated fibrillary glomerulonephritis and IgA nephropathy
Authors: Said Samar M , Rocha Alejandro Best , Valeri Anthony M , Sandid Mohamad , Ray Anhisekh Sinha , Fidler Mary E , Alexander Mariam Priya , Larsen Christopher P , Nasr Samih H 
Published: September 2020

Abstract

Background
Coexistence of fibrillary glomerulonephritis (FGN) and immunoglobulin A (IgA) nephropathy (IgAN) in the same kidney biopsy (FGN–IgAN) is rare, and the clinicopathologic characteristics and outcome of this dual glomerulopathy are unknown.

Methods
In this study, 20 patients with FGN–IgAN were studied and their characteristics were compared with 40 FGN and 40 IgAN control patients.

Results
Concurrent IgAN was present in 1.8% of 847 consecutive FGN cases and was the second most common concurrent glomerulopathy after diabetic nephropathy. FGN–IgAN patients were overwhelmingly White (94%) and contrary to FGN patients were predominantly (60%) males. Compared with IgAN patients, FGN–IgAN patients were older, had higher proteinuria, a higher incidence of renal insufficiency, and a lower incidence of microhematuria and gross hematuria at diagnosis. Six (30%) patients had malignancy, autoimmune disease or hepatitis C infection, but none had a secondary cause of IgAN or clinical features of Henoch–Schonlein purpura. Histologically, all cases exhibited smudgy glomerular staining for immunoglobulin G and DnaJ homolog subfamily B member 9 (DNAJB9) with corresponding fibrillary deposits and granular mesangial staining for IgA with corresponding mesangial granular electron-dense deposits. On follow-up (median 27 months), 10 of 18 (56%) FGN–IgAN patients progressed to end-stage kidney disease (ESKD), including 5 who subsequently died. Serum creatinine at diagnosis was a poor predictor of renal survival. The proportion of patients reaching ESKD or died was higher in FGN–IgAN than in IgAN. The median Kaplan–Meier ESKD-free survival time was 44 months for FGN–IgAN, which was shorter than IgAN (unable to compute, P = 0.013) and FGN (107 months, P = 0.048).

Conclusions
FGN–IgAN is very rare, with clinical presentation and demographics closer to FGN than IgAN. Prognosis is guarded with a median renal survival of 3.6 years. The diagnosis of this dual glomerulopathy requires careful evaluation of immunofluorescence findings, and electron microscopy or DNAJB9 immunohistochemistry.
Current use and safety of novel oral anticoagulants in adults with congenital heart disease: results of a nationwide analysis including more than 44 000 patients
Authors: Freisinger Eva , Gerß Joachim , Makowski Lena , Marschall Ursula , Reinecke Holger , Baumgartner Helmut , Koeppe Jeanette , Diller Gerhard-Paul 
Published: September 2020

Abstract

Aims
To evaluate the use of novel oral anticoagulants (NOACs) compared with vitamin K antagonists (VKAs) in adult congenital heart disease (ACHD) and assess outcome in a nationwide analysis.

Methods and results
Using data from one of Germany’s largest Health Insurers, all ACHD patients treated with VKAs or NOACs were identified and changes in prescription patterns were assessed. Furthermore, the association between anticoagulation regimen and complications including mortality was studied. Between 2005 and 2018, the use of oral anticoagulants in ACHD increased from 6.3% to 12.4%. Since NOACs became available their utilization increased constantly, accounting for 45% of prescribed anticoagulants in ACHD in 2018. Adult congenital heart disease patients on NOACs had higher thromboembolic (3.8% vs. 2.8%), MACE (7.8% vs. 6.0%), bleeding rates (11.7% vs. 9.0%), and all-cause mortality (4.0% vs. 2.8%; all P &lt; 0.05) after 1 year of therapy compared with VKAs. After comprehensive adjustment for patient characteristics, NOACs were still associated with increased risk of MACE (hazard rate—HR 1.22; 95% CI 1.09–1.36) and increased all-cause mortality (HR 1.43; 95% CI 1.24–1.65; both P &lt; 0.001), but also bleeding (HR 1.16; 95% CI 1.04–1.29; P = 0.007) during long-term follow-up.

Conclusion
Despite the lack of prospective studies in ACHD, NOACs are increasingly replacing VKAs and now account for almost half of all oral anticoagulant prescriptions. Particularly, NOACs were associated with excess long-term risk of MACE, and mortality in this nationwide analysis, emphasizing the need for prospective studies before solid recommendations for their use in ACHD can be provided.