bluuebunny/crossref_metadata_2025_split huggingface dataset:
Necessary and sufficient conditions for the existence of a classical solution of the mixed problem for the wave equation on a graph
Authors: Burlutskaya M Sh 
Published: May 2021

Abstract
We study a mixed problem for the wave equation with integrable potential on the simplest geometric graph consisting of two ring edges that touch at a point. We use a new approach in the Fourier method to obtain necessary and sufficient conditions for the existence of a classical solution. We do not use refined asymptotic formulas for the eigenvalues and any information on the eigenfunctions. The solution is represented by a rapidly convergent series.
Interval estimation of conditional probabilities in Bayesian Belief Network
Authors: Gagarin Yu E , Nikitenko U V , Stepovich M A 
Published: May 2021

Abstract
An interval estimation of conditional probabilities in Bayesian belief network is considered, taking into account the uncertainty of the initial data. To account for errors in the values of functions and arguments, it is proposed to use confluent analysis methods. It is assumed that the conditional probability densities correspond to the normal distribution law. Formulas for interval estimation of conditional probability densities are given, taking into account the errors of their parameters. The results of mathematical modeling of obtaining point and interval estimates of conditional and a posteriori probabilities of the Bayesian belief network are shown.
Computer modeling of process in earth structures of dam type
Authors: Gaynazarov S M , Polatov A M , Ikramov A M , Pulatov S I 
Published: May 2021

Abstract
The article deals with computer modeling of processes in earth structures of dam type, taking into account the nonlinear properties of soil. Large vertical and planned displacements of soil in the body of the dam are formed due to changes in soil density or as a result of the development of plastic shear strains. The application of the von Mises-Botkin and Coulomb hypotheses to the development of plastic strain is investigated.
Mathematical modeling of elastic soil acid treatment
Authors: Galtsev O V 
Published: May 2021

Abstract
The study is devoted to an initial boundary value problem describing the process of cleaning the bottomhole zone of an oil well with acid solution. It is assumed that the soil frame is an elastic solid body and the pore space has double porosity. The physical process is described at the microscopic level by the Stokes equations for the liquid component, the diffusion-convection equation for the concentrations of acid and chemical reaction products, and the Lame equations for the solid frame. Due to soil dissolution, the pore space has an unknown (free) boundary. The lattice Boltzmann method (LBM), the immersed boundary method (IBM) and the finite element method (FEM) are used for computer simulation. Finally, discretization of equations and results of numerical solutions are presented.
Numerical investigation of compact grid-characteristic schemes for acoustic problems
Authors: Golubev V I , Shevchenko A V , Khokhlov N I , Nikitin I S 
Published: May 2021

Abstract
In this paper, an acoustic approximation is considered, which allows to describe the propagation of longitudinal waves in geological media. For the two-dimensional case, a compact numerical scheme is described that provides an increased approximation order on a two-point spatial stencil. To construct it, we used the method of splitting along coordinate axes and the differential continuation of the original system of equations. A number of numerical tests have been carried out, confirming the increased order of approximation.
Development of the mathematical model of the force actuator for deployment of large-sized space structures
Authors: Zimin V N , Krylov A V , Shakhverdov A O 
Published: May 2021

Abstract
A special class of large-sized space systems is formed by transformable structures that have different configurations in transport and operating states. Transformable large-sized space structures are delivered into orbits in a folded transport state and after that they are deployed into operating position. Now problems of the mathematical modeling of deployment dynamics of such systems attract a great interest of scientists. When the structure is transformed, impact dynamic loads arise in the system elements. To ensure a smooth «controlled» opening of the transformable structures and to exclude the dynamic impact loads in their constructed elements, it is proposed to use force actuators made of material with a shape memory effect. Now, to create mechanisms with elements made of the materials with the shape memory effect, the role of experimental methods is very important. Preliminary experimental studies of the force actuator made of such material as titanium nickelide were carried out. Deformation and force characteristics of the actuator obtained in these studies prove the possibility to use it for reliable deployment of the promising transformable space structures. Based on the fulfilled theoretical and experimental studies, the mathematical model describing the force actuator functionality is proposed.
Solution of the first basic physically nonlinear problem of elasticity theory for anisotropic bodies
Authors: Ivanychev D A , Novikov E A 
Published: May 2021

Abstract
The study looks upon the process of the physically non-linear deformation of transversely isotropic homogeneous continuous solid bodies made from composites where the reinforcing elements are far more rigid than the binder. The solution of the physically non-linear problems employs the simplified theory of plasticity as proposed by B.E. Pobedra. The study proposes an approach to the writing out of an explicit solution that builds on the small parameter method. Ilyushin plasticity functions (that fall within the generalized Hooke’s law) are assigned discrete small values, and the resulting equations are then decomposed into power series in small parameters. The values of such small parameters are the measures of the deflection of the non-linear vs. the linear medium. Such decomposition produces an analytical coordinate & small parameters function enabling an immediate solution of the non-linear problem using just one linear elasticity field, which, in turn, is also created exclusively in reliance on the method of boundary states. Below are the results of solutions of test problems featuring a transversely isotropic cylinder with homogeneous boundary conditions. High precision in this case is achieved as early on as the third iteration. In problems with non-trivial boundary conditions, maximal precision is achieved at the first iteration and heavily depends on small parameter values. Each of the problems presented provides a detailed convergence analysis and graphic illustrations of the results.
Calculation of the problem of thermoplasticity on the example of a stationary power plant flange using free software Code Aster
Authors: Maksimova E A , Cherednichenko A V , Savelyeva I Yu 
Published: May 2021

Abstract
The construction of a geometric model and finite element approximation of the flange of a stationary power plant is presented. Modelling and meshing were held using Salome-Meca modules. The paper provides a brief description of the key commands in AsterStudy module for modeling this problem. A numerical calculation of the heat-stress state of the flange of a stationary power plant was performed using free Code Aster software. Distributions of temperature for four periods, flange deformation, displacements, and also equivalent von Mises stresses are given as a results of the study.
Modified ant colony optimization algorithm for solving the vehicle routing problem with a given load capacity
Authors: Medvedev S N , Medvedeva O A 
Published: May 2021

Abstract
The article presents a mathematical model of the Vehicle routing problem with loading constraints in the form of a mathematical programming problem. A modification of the Ant colony optimization algorithm is presented to solve the problem. The main idea of the modification is to use the probabilistic rule of returning the agent (ant) to the depot before full unloading. The source of such behavior of the agent can be the concept of «fullness» of the ant. The computational experiment for comparing the classical and modified Ant colony optimization algorithms is presented. Testing was carried out according to two schemes: intensive testing and cross-testing. The conclusions about the efficiency of the proposed algorithm are presented.
An approach to design of large-sized deployable hoop space antenna reflector
Authors: Meshkovsky V Ye , Sdobnikov A N , Kisanov Yu A 
Published: May 2021

Abstract
Amongst the large-sized transformable space antennas, the most attention is currently paid to developing of antennas with hoop-shaped reflectors. The developers are faced with the necessity of looking for optimal design concepts. This paper shows the various concepts of building of the reflectors of the cable-rod scheme, containing a circular load-bearing framework (load-bearing rim) with a deployment drive set on it and the reflecting surface shape-generating structure, assembled into a single construction by the cable and rod elements. The difference between the proposed design concepts of the reflectors is the various structures of the controllable unfolding mechanisms. In the first alternative of the reflector structure, the unfolding process is supported by the cable, which restrains relative displacements of the tips of the initially compressed springs. The second alternative supposes the cable not to be the restraining element, but an active unit of the unfolding mechanism. This paper also describes various alternatives for connection between tension tie cables and the load-bearing rim. It is shown that the alternative of connection of the tension tie cables to the middles of the load-bearing rim edges allows to perform stress analysis of the structure elements and to obtain required characteristics of the spring drive. The numerical calculations for optimal angular position of the deployment drive pulleys holder relative to the sections of the load-bearing rim for the second alternative of the reflector design, which provides the most force effect on shape-generating structure of the reflector, when the knitted mesh fabric is being pulled, are under consideration in this article. The calculations are confirmed by experimental investigations.
Design features of an information-measuring and control system for landing a swarm of small unmanned aerial vehicles
Authors: Pasechnikov I I , Pasechnikov R I , Nazarov A S , Rodionov D V 
Published: May 2021

Abstract
The problem of a small unmanned aerial vehicles (SUAV) swarm landing on a robotic platform is solved. The necessity of creating a controlled waiting area for a SUAV in the landing system is shown using simulation. The principle of SUAV air traffic organisation in the space-time waiting zone and the issues of a safe landing are revealed. The structure of the information-measuring and control system of the SUAV landing with the space-time waiting area and the buffer landing zone is proposed. Its main features are given and the possibility for landing a SUAV swarm of various structure is shown.
River mouth areas hydrodynamics mathematical modeling
Authors: Sukhinov A I , Kuznetsova I Yu , Chistyakov A E , Litvinov V N 
Published: May 2021

Abstract
The article is devoted to the mathematical modeling results description of hydrodynamic processes in seas mouth areas. 3D hydrodynamics mathematical model description is given, which is used to calculate the 3D velocity vector fields of the aquatic environment movement in mouth areas. The approximation of the differential equations of the mathematical model is based on the balance method taking into account the fullness of the control areas. The use of this combination of methods made it possible to more accurately description the complex geometry of the coastline and seabed. Due to this, it was possible to reduce the calculation error at the boundaries of the computational domain and to increase the calculation accuracy. A software package for modeling hydrodynamic processes in mouth areas has been developed in C++. The description of the software package and the results of its operation are given.
Using of machine learning methods in cardiology
Authors: Firyulina M A , Kashirina I L 
Published: May 2021

Abstract
In the modern world, artificial intelligence and machine learning affect many areas of life. Medicine is no exception. It is one of the most important areas of application of intelligent technologies. This article describes the experience of building machine learning models in cardiology and discusses the features of their development, analyses various machine learning algorithms used in problems of cardiological practice, examines ways to improve their accuracy and efficiency.
Application of the Q-learning algorithm for the intellectual mode of the manipulator arm for moving to a present position
Authors: Yakovlev A Yu , Krasnaya A A , Medvedev S N 
Published: May 2021

Abstract
The article is devoted to the search for a certain kinematic scheme that determines the movement of the arm links of an industrial manipulator. A robotic complex with a single-circuit hydraulic system of arm element drives is considered. The problem of the automatic transition of the arm to a user-specified state has been solved, taking into account the restrictions on the simultaneous movement of the arm links and the minimum and maximum heights of the manipulator. To solve the problem, we used the machine learning method – Q-learning.
Radiopacity endowed magnetic nanocomposite with hyperthermia and in vitro mineralization potential: a combinatorial therapeutic system for osteosarcoma
Authors: Sneha K R , Sreeja S , Sailaja G S 
Published: May 2021

Abstract
The development of clinically advanced multifaceted therapeutic materials for osteosarcoma is at the forefront of cancer research. Accordingly, this work presents the design of a multifunctional magnetic nanocomposite composed of maghemite, strontium doped hydroxyapatite and silica nanoparticles prospectively holding indispensable therapeutic features such as magnetic hyperthermia, in vitro biomineralization, sustained drug release and intrinsic radiopacity for the treatment of osteosarcoma. The optimal composition has been identified by sequentially modulating the ratio of precursors of the magnetic nanocomposite synthesized by sol–gel technique. Structural and morphological characterization by x-ray diffraction, fourier transform infrared spectrum, Brunauer–Emmet–Teller and transmission electron microscopy analyses followed by VSM, hyperthermia and micro-CT analyses essentially assisted in the selective configuration of biofunctional properties. Results exemplify that MSHSr1 has a saturation magnetization of 47.4 emu g−1 and attained hyperthermia temperature (42 °C) at a very low exposure time of 4 min. MSHSr1 is further unique with respect to its exceptional x-ray attenuation ability (contrast enhancement 154.5% in digital radiography; CT number 3100 HU), early biomimetic mineralization (in vitro) evident by the formation of spheroidal apatite layer (Ca/P ratio 1.33) harvested from FESEM–EDX analysis and controlled release of Doxorubicin, the clinically used chemotherapeutic drug: 87.7% at 120 h in tumour analogous pH (6.5) when compared to physiological pH (71.3% at 7.4). MTT assay complemented with cytoskeleton (F-actin) staining of human osteosarcoma (HOS) cells affirm biocompatibility of MSHSr1. In vitro biomineralization authenticated by Alizarin red S and von Kossa staining has been further corroborated by semi-quantitative calcium estimation of HOS cells cultured with MSHSr1 for two weeks. The results therefore validate the multifunctionality of MSHSr1, and hence could be proposed as a combinatorial therapeutic nanocomposite for osteosarcoma treatment.
Independent oil palm smallholder management practices and yields: can RSPO certification make a difference?
Authors: De Vos Rosanne E , Suwarno Aritta , Slingerland Maja , Van Der Meer Peter J , Lucey Jennifer M 
Published: May 2021

Abstract
Smallholders are a substantial part of the oil palm sector and thus are key to achieving more sustainable production. However, so far their yields remain below potential. The Roundtable on Sustainable Oil Palm (RSPO) aims to include smallholders in sustainability certification to strengthen rural livelihoods and reduce negative environmental impacts. This study aims to determine if and how certified smallholders perform differently from their non-certified counterparts in terms of management practices and yields, and to what extent this is related to RSPO certification. Certified smallholders had significantly better management practices in terms of planting material (tenera) and fertiliser use (16.8 vs 4.8 bags ha−1 yr−1) and had significantly higher yields (22.5 vs 14.5 ton fresh fruit bunches ha−11 yr−11, corrected for palm age). Planting material and harvesting frequency significantly explained higher yields. These differences could not be attributed to certification per se but were probably due to pre-certification conditions, including strong group organisation. It remains a question as to how sustainability certification can be a driver of change by including smallholders who have relatively larger yield gaps, and who lag behind in eligibility criteria for certification.
Fractional Brownian motion in superharmonic potentials and non-Boltzmann stationary distributions
Authors: Guggenberger Tobias , Chechkin Aleksei , Metzler Ralf 
Published: May 2021

Abstract
We study the stochastic motion of particles driven by long-range correlated fractional Gaussian noise (FGN) in a superharmonic external potential of the form U(x) ∝ x
2n
(

n
∈
N

). When the noise is considered to be external, the resulting overdamped motion is described by the non-Markovian Langevin equation for fractional Brownian motion. For this case we show the existence of long time, stationary probability density functions (PDFs) the shape of which strongly deviates from the naively expected Boltzmann PDF in the confining potential U(x). We analyse in detail the temporal approach to stationarity as well as the shape of the non-Boltzmann stationary PDF. A typical characteristic is that subdiffusive, antipersistent (with negative autocorrelation) motion tends to effect an accumulation of probability close to the origin as compared to the corresponding Boltzmann distribution while the opposite trend occurs for superdiffusive (persistent) motion. For this latter case this leads to distinct bimodal shapes of the PDF. This property is compared to a similar phenomenon observed for Markovian Lévy flights in superharmonic potentials. We also demonstrate that the motion encoded in the fractional Langevin equation driven by FGN always relaxes to the Boltzmann distribution, as in this case the fluctuation-dissipation theorem is fulfilled.
Effect of cropping rotation patterns on rice productivity in irrigated rice fields
Authors: Suprihatin A , Purwanto B H , Hanudin E , Nurudin M 
Published: May 2021

Abstract
Crop rotation has an important role in increasing soil fertility (chemical, physical and biological), production, and sustainable land use. The aim of this study to determine the variables affecting rice productivity in irrigated rice fields in several crop rotation patterns. The fieldwork was taken place in irrigated rice fields, Imogiri District - Bantul, Yogyakarta, Indonesia. The experimental design used in this study was Oversite design, on four irrigated rice fields that applied four different crop rotation patterns: rice-rice-corn (RRM), rice-rice-soybean (RRS), rice-rice-rice ( CCR), and rice-rice-rice grown organically (COR). The rice variety Inpari 23 was grown during wet season (February - May 2018) while during dry season (June – September 2018), the rice variety Mentik Wangi was planted. The data were analyzed by ANOVA at 5% level, and continued with HSD level 5% using SAS 9.1.3. portable, while the correlation analysis used SPSS. The results showed that the highest production of MDG was obtained from CCR cropping pattern while the lowest production from RRM cropping pattern. The Inpari 23 grown in wet season produced higher MDG (6,092 kg ha−1 ) than Mentik Wangi which grown in dry season (5,110 kg ha−1 ). The production of MDG has a positive correlation with plant height, dry weight of grain and weight of 1.000 grains. Since the irrigated rice fields used in this study had a moderate level of fertility, the results showed that differences in crop rotation patterns and rice cultivation techniques in irrigated rice fields that have moderate soil fertility did not affect crop productivity. The productivity have more influenced by the choice of rice varieties planted in each planting period.
Effect of CaCl2 and Alginate-Essential Oil Edible Coating in Maintaining Quality and Antioxidant Content in Rose Apple cv. Dalhari
Authors: Anjani A M , Setiawan C K , Utama N A 
Published: May 2021

Abstract
Information on the treatment of edible coatings alginate and various concentrations of essential oils has not been known to antioxidant and anthocyanin changes in rose apple during storage.This study was aimed to determine the effect of CaCl2 and edible coating towards changes in antioxidants, anthocyanins, and chlorophyll during storage. It was also to determine the concentration of the best combination of immersion of CaCl2 and essential oils to the antioxidant, anthocyanin, and chlorophyll content found in rose apple var. Dalhari. The research was conducted by experimental CRD (Completely Randomized Design) factorial design. The first factor was the concentration of CaCl2 consist of two levels ie 0% and 2%. The second factor was the type and concentration of essential oil consist of 3 levels, namely 1% vanilla, 0.7% cinnamon and 0% essential oil. The results of the combination of CaCl2 and essential oils has no significant effect on antioxidant, anthocyanin, and chlorophyll content.
Response of Trichoderma sp and shallot varieties towards plant growth and disease incidence
Authors: Korlina E , Sulastrini I , Waluyo N 
Published: May 2021

Abstract
The main diseases that commonly attack shallots include purple blotch disease (Alternaria porri), anthracnose (Colletotrichum gloeosporioides), wilt (Fusarium oxysporum) and Stemphylium vesicarium. Purple blotch disease can cause yield losses of 3-57%. The research is aimed to measure the response of Trichoderma sp and other varieties to the growth and development of shallot disease. The study was conducted at IP2TP Margahayu Indonesian Vegetable Research Institute (IVEGRI), in August - November 2019. The research used a randomized block design (RBD) with 12 treatments and 3 replications. The treatments consisted of three varieties which are Batu Ijo, Sumenep, Trisula, Violeta 1, Maja Cipanas, and Ambasador in combination with Trichoderma and without Trichoderma. Results for the parameters of plant height and number of leaves showed that varieties that have been Trichoderma applied have reached higher height than those without Trichoderma. Ambasador showed the highest plant height (46.27 cm) and the highest number of leaves (44.16 cm). A The intensity of the purple blotch disease attacks A. porri (0.67-8,00%) and S. vesicarium (6.67-23.33%) on all varieties treated with Trichoderma lower than without Trichoderma s for the number of tillers, it is almost the same as an average of 6-7 tillers, except for Sumenep that has only 3-4 seedlings. For wet weight and dry weight per clump in the varieties applied to Trichoderma, the weight per clump is higher than those without Trichoderma, and yet wet weight and dry weight for Batu Ijo without Trichoderma application are relatively similar.