bluuebunny/crossref_metadata_2025 huggingface dataset:
Canonical quantization of anisotropic Bianchi I cosmology from scalar vector tensor Brans Dicke gravity
Authors: Ghaffarnejad Hossein
Published: December 2019

We applied a generalized scalar-vector-tensor Brans Dicke gravity model to study canonical quantization of an anisotropic Bianchi I cosmological model. Regarding an anisotropic Harmonic Oscillator potential we show that the corresponding Wheeler de Witt wave functional of the system is described by Hermit polynomials. We obtained a quantization condition on the ADM mass of the cosmological system which raises versus the quantum numbers of the Hermit polynomials. Our calculations show that the inflationary expansion of the universe can be originate from the big bang with no naked singularity due to the uncertainty principle.
Advanced methods of low cost mission design for the Galilean moons exploration
Authors: Grushevskii Alexey , Golubev Yury , Koryanov Victor , Tuchin Andrey , Tuchin Denis
Published: December 2019

The implementation of the deep space expeditions to the outer Solar system is the one of main priorities of modern astrodynamics. One of the irritating factors for this is the probability of the life determination in the underground ocean at the Jovian icy moon Europa. In that regard the realization of the cosmic projects using the spacecraft — orbiters around the Jovian Galilean Moons and especially the descent modules implementation on their surface is one of the basic focuses of the current international cosmic space researches collaboration. The mission design of such cosmic projects must be executed using new advanced methods for their planning: Low Energy Tours exploring, Favourable Total Radiation Doze of the spacecraft (SC) provision, and tolerable maintenance of the SC’s Time of Flight during the Jupiter system phase. Furthermore, the saving character of the trajectory design for the artificial satellite of the Galilean moon necessary required the smallness of the SC’s velocity relative this moon, i.e. the smallness of the SC’s hyperbolic velocity excess vector. In this work multibody bunch adaptive synthesis algorithms to overcome ballistic determinism expressed by existing of the integral of Jacobi in the basic CR3BP (circular restricted three body problem) are developed. It is shown that the diversity of the gravity of the ensemble in the Jovian system, not only complicates the accurate ballistic mission analysis, but, when its multibody effective use, allowing you to tailor flowed algorithms for the constructing scenarios of gravity assist maneuvers for interplanetary missions design, including circumvention of dangerous radiation areas, as well as landing at selected Galilean moon at a reasonable cost, resources and time.
Mathematical and computer modelling of the nonlinear dynamics of particle beams in cyclic accelerators
Authors: Andrianov S.N. , Krushinevskii E.A.
Published: December 2019

The article explores the methods of mathematical and computer modelling of the nonlinear dynamics of particle beams in cyclic accelerators in terms of the matrix formalism using both numerical and symbolic representations of the corresponding nonlinear differential equations. This paper shows how the matrix formalism approach allows the use of modern computational algorithms and artificial intelligence methods for more efficient and flexible modelling of particle beam dynamics in accelerators. Also, the article proposes a method of representing control elements using LEGO objects, which makes it possible to increase the efficiency of using control elements from a computational point of view and to facilitate the process of modelling particle dynamics.
Reputation in Majority Rule Model leading to democratic states
Authors: Oliveira Leonardo S. , Rodrigues Anderson C. , Forgerini Fabricio L.
Published: December 2019

We study the Majority Rule (MR) model, a sociophysics model developed to describe how a group of agents with initial different opinions can reach consensus. At each instant of time, a group is selected at random and discuss among each other. After the discussion, all members of this discussion group follow the majority opinion. The number of agents in the discussion group is not fixed and it is selected each instant of time from a Gaussian distribution. The system dynamics stops when only one opinion survive. In this work we introduced in the MR model a ‘reputation’ for each agent, a weight to be considered in the system dynamics. Our results show that the introduction of reputation leads the system to a steady state in which not every agent on the system have exactly the same status, but a majority of them sharing the same opinion. In addition, our model with the inclusion of reputation do not show the critical point usually observed. Instead we have obtained the critical point pc
= 1, in contrast with the standard Majority Rule model.
Novel approach for accurate detection of contaminating human mitochondrial DNA in next-generation sequencing data
Authors: Ishiya Koji , Ueda Shintaroh
Published: December 2019

DNA molecules are degraded after the death of an organism. However, the degree and rate of DNA degradation enormously vary depending on environmental conditions, such as temperature or humidity, which greatly affect DNA preservation. Most samples excavated in warm, humid, or dry areas are often poorly preserved samples with from<0.1%-1% endogenous DNA. In these degraded samples, the contamination by exogenous DNA remains a potential challenge, no matter how much effort is made to prevent it. For an accurate DNA sequence analysis, quality control must be thoroughly performed, using the mitochondrial DNA as an indicator of exogenous DNA contamination. Here, we propose a practical approach for detecting exogenous human mitochondrial macro haplogroups, and discuss the effectiveness of this approach using simulated data. Our approach is based on the Bayes classification, which is a supervised machine learning algorithm, and it can detect a contaminating macro haplogroup in high-throughput sequencing data. This approach can help validate the quality of high-throughput sequencing data from possibly contaminated or degraded human samples.
Entropy production rate of diffusivity fluctuations under diffusing diffusivity equation
Authors: Itto Yuichi
Published: December 2019

Entropy production rate is discussed for diffusivity fluctuations of RNA-protein particles in cytoplasm of a living cell. The rate under the diffusing diffusivity equation is shown to become positive. The lower bound on the rate that suppresses the entropy production is also presented.
The error function in fractional differential equations
Authors: Funes Jorge Olivares , Kari Elvis Valero , Martin Pablo , Maass Fernando
Published: December 2019

The objective of this paper is to solve the fractional differential equation

d
α

y

d

x
α

=
e
r

f

(
x
)

;

y

(
k
)

(
0
)

=
0
;

k
=
0
,
…
m
−
1
;

m
−
1
<
α
⩽
m
;

m
∈
ℕ

Generalized hypergeometric functions have been found as solutions of these kind of differential equations. To obtain these the Caputo definition of fraction of derivative has been used as well as Laplace Transform.

We will show the type of gereralized hypergeometric solutions that are obtained by means of the definition of the fractional derivative of Caputo and the Laplace transform.
Modelling meson clouds using coherent states
Authors: Fiolhais Manuel
Published: December 2019

A simple model for the quark-pion interaction is used to test the validity of a variational approach which is often used in realistic models for baryons. That simple model is solvable in the weak coupling regime as well as in the strong one. As we show, the approach consisting of a meson description by coherent states supplemented by an angular momentum and isospin projection onto states of good quantum numbers (such as the nucleon or delta resonance) is flexible enough at least to reproduce the accurate results in those two limits. However, in order for these results to be achieved, the so-called variation after projection method has to be applied. This study gives confidence for using similar techniques in realist models of quarks and mesons in interaction.
Integration of electromagnetic methods of intubation of stratified mediums on the basis of direct and alternating currents.
Authors: Dimitrienko Yu I , Krasnov I K , Zubarev K M
Published: December 2019

In this work the integration of two methods of electroinvestigation is considered. One method represents intubation by a direct current, the second intubation by alternating current. The integration is carried out for the purpose of increase in accuracy of results of the solution of the inverse task, the problem is solved in a twodimensional approximation. The direct task for the first and second method is solved numerically. The received values were compared with the experimental datas. The inverse task is formulated as a problem of minimization with the functional considering the experimental values received by both the first and second method of electroinvestigation. The problem of optimization is solved on a compact (for each parameter are set top and bottom border).
Theoretical Justification of Experimental Investigation of Gravity-Capillary Method for Gas-Liquid Mixtures Intake
Authors: Ivanov M Yu , Resh G F
Published: December 2019

The process of interaction of an adaptive spatial permeable capillary phase separator with a gas-liquid interface in a vessel in the gravitational field of the Earth was investigated. The existence of a natural comprehensive compression force acting on a capillary phase separator was theoretically justified and experimentally confirmed. This force is compensated by the structure rigidity in classical devices. It was shown that the volume of the capillary phase separator covered by a gas was decreased in a compliant structure under the action of this force in the liquid outflow process. Due to this, it is possible to maintain a total pressure differential for the capillary phase separator at low flow rates of the liquid below a capillary differential defined by the well-known Laplace’s formula. This effect allows reducing a remaining portion of a liquid in a vessel and expanding the practical application area of capillary phase separators including intake systems operating under conditions of elevated accelerations and temperatures.
Dynamics of various population groups in a two-dimensional spatial economy model.
Authors: Gerasimov S , Inovenkov I , Nefedov V
Published: December 2019

The system of parabolic partial differential equations, which describes the dynamics of various population groups in an urban environment, is considered. The model takes into account both the interaction between different groups in the process of their cohabitation and the diffusion processes of population migration. Various examples of world megacities are considered and some general principles of urban development are formulated.
Design of multiplierless minimum-phase FIR filters using palindromic polynomials and sharpening
Authors: Jovanovic Dolecek G , Salguero Luna SA
Published: December 2019

Minimum phase (MP) filters have all zeros inside the unit circle and have a minimum group delay and a minimum energy delay properties, especially useful in communication systems. The special class of MP filters has all zeros inside and on the unit circle. This paper presents a method for design of this class of MP FIR (Finite Impulse Response) digital filters without multipliers The method is based on palindromic polynomials and sharpening technique. The coefficients of palindromic polynomials are presented as a sum of powers of two, and consequently can be implemented by using only adders and shifts, resulting in a multiplierless design. Two classes of palindromic polynomials, having all zeros on the unit circle, are considered. Next, the sharpening technique was applied to improve the magnitude characteristic and to move zeros inside of unit circle. The choice of the design parameters is also presented. All zeros, of the designed MP filter, are inside or on the unit circle. Method is illustrated with one example.
On Convergence Speed of Parallel Variants of GPBiCG Method for Solving Linear Equations
Authors: Abe Kuniyoshi , Ikuno Soichiro
Published: December 2019

The hybrid Bi-Conjugate Gradient (Bi-CG) methods such as Bi-CG stabilized (Bi-CGSTAB), Generalized Product-type based Bi-CG (GPBiCG), and BiCGstab(ℓ) are well-known for efficiently solving linear equations. GPBiCG and BiCGstab(ℓ) are more effective and robust than Bi-CGSTAB on problems with strongly nonsymmetric matrices. On present petascale high-performance computing hardware, the scalability of Krylov subspace methods has recently become increasingly prominent. The main bottleneck for efficient parallelization is the inner products which require a global reduction. The parallel variants of Bi-CGSTAB reducing the number of global communication phases and hiding the communication latency have been proposed. However, it has been reported that the convergence of the parallel variants of Bi-CGSTAB is affected by rounding errors than that of the standard Bi-CGSTAB, and is not as robust as the standard. In this paper, therefore, following [1], we design parallel variants of GPBiCG, which converges faster and is more robust than Bi-CGSTAB. Then we compare the convergence speed between the standard GPBiCG and the parallel variants by numerical experiments.
Some elements of charge kinetics for particles and splinters in reference to the process of nuclear disintegration
Authors: Tertychny-Dauri V Yu
Published: December 2019

This work is devoted to solution of some problems connected with kinetic equations of reproduction for charged particles and charged splinters of the fission inside of nuclear toroidal electromagnetic generator (nuclegen). There are discussed questions of solutions behaviour for charged equations. Special attention is paid to charge kinetics of the nuclegen under the influence of small random disturbances and stimulated by this influence to analysis of stochastic motion properties for the ionite gas.
CFD results for dust concentration in ABL near vegetative barriers
Authors: Řezníček Hynek , Beneš Luděk
Published: December 2019

The numerical simulation of dust spreading inside the Atmospheric Boundary Layer are usually modelled by commercial CFD software. This contribution deals with the similar problem by using an in-house solver, based on finite volume method AUSM+up scheme. System of the RANS equations for viscous incompressible flow with variable potential temperature is used for description of the flows. The Richards-Hoxey [7] wall function is implemented to correctly caption the turbulence near the ground. The effects of vegetative barriers for the dust concentration near a surface coal mine were studied. Petroff’s [6] model of the dust deposition on vegetation is employed. The model includes four main processes which lead particles to depose on the leaves: Brownian diffusion, interception, impaction and gravitational settling.
Dispersionless limit of the (1+1)-dimensional Fokas-Lenells equation
Authors: Zhassybayeva Meruyert , Yesmakhanova Kuralay , Myrzakulov Ratbay
Published: December 2019

Nonlinear dispersionless equations can be obtained as dispersionless limits (quasiclassical limits) of integrable hierarchies of equations or by constructing a system of hydrodynamic type. In this paper, the dispersionless limit of the (1+1)-dimensional Fokas-Lenells equation is found. We present Lax pair for this dispersionless equation. As well known, the Fokas-Lenells equation characterizes the propagation of ultrashort nonlinear light pulses in optical fibers. Exact solutions of the dispersionless version of the Fokas-Lenells equation describe nonlinear shock waves in optical fiber systems. By using the obtained results, one can find shock wave solutions of the dispersionless equation, which have different physical applications.
The linear response function of a mixed dislocation in ferroelectrics
Authors: Dezhin V V , Nechaev V N
Published: December 2019

Bending vibrations of a mixed dislocation in a uniaxial ferroelectric are considered, the dislocation line is located along the ferroelectric axis. Based on the complete system of equations describing the vibrations of a ferroelectric crystal with a dislocation, system of equations for the mixed dislocation dynamics in a linear approximation in the dislocation displacement is written. An expression for the Peach–Koehler force acting on the dislocation is obtained, and the linear response function of the mixed dislocation is found.
The differential-q-difference 2D Toda equation: bilinear form and soliton solutions
Authors: Kutum B.B. , Yesmakhanova K.R. , Shaikhova G.N.
Published: December 2019

In this paper, the differential-q-difference 2D Toda lattice is studied. Hirota’s bilinear technique is applied to it. Soliton solutions are constructed through the resulting bilinear form for the differential-q-difference 2D Toda equation.
Unifying approach to score based statistical inference in physical sciences
Authors: Kus Vaclav , Richard Finger
Published: December 2019

In this contribution the statistical inference based on score functions is developed with the aim of future utilization throughout different fields of physics, for example in detector collision data processing or neutrino prongs matching. New score functions between theoretical and empirical probability measures are defined and the corresponding minimum score estimators are presented. We find that consistency of different estimators in various score functions leads to the well-known consistency in commonly used statistical distances or disparity measures between probability distributions. Conditions under which a specific score function pass to ˚–divergence are formulated. Conversely, each ˚–divergence is a score function. Furthermore, the minimization of arbitrary divergence score function leads to the classical histogram density estimator and thus can be used to alternative interpretation of histogram based calculations in (high energy) physics. The Kolmogorov-Smirnov testing statistics can be achieved through absolute score function under the class of mutually complement interval partitioning of the real line. It means that the most popular statistical methods, such as histogram estimation and Kolmogorov goodness of fit testing used in physics, can be covered by one unifying score based statistical approach. Also, these methods were previously successfully applied to data sets originated from the particular material elasticity testing (nondestructive defectoscopy) within Preisach-Mayergoyz space modeling.
A Case Study of Closed Universe that Fits the Cosmological Data of Supernovae of Type Ia
Authors: Adda FayȈcal Ben
Published: December 2019

In this paper a case study of an homogeneous and isotropic expanding space-time that expands via expansion of its basic element raises a fundamental distinction between recession movement of matter and space expansion. We prove that observing matter recession at an accelerating rate is not an indication for the acceleration of the universe expansion. More precisely, we show that the observed acceleration in the recession movement of galaxies is naturally due to the space-time deceleration. The case study provides us with a possible space-time with independent movement that might produce the observed behavior of galaxies registered for the redshift z < 0.5 as well as for the redshift z < 0.5. This case study calls into question the recent interpretation of the accelerating recession movement of galaxies as indication for the universe acceleration.
Educational Robotics as a Teaching tool in higher education institutions: A bibliographical analysis
Authors: Sánchez H , Martínez L S , González J D
Published: December 2019

The incorporation of robotics as an educational tool in higher education institutions has represented in recent years an innovative mechanism towards improving the teaching of mathematics, physics, and development of control software. This work shows our research about the use of efficient robotics in educational processes in higher education institutions and their perspectives of new innovations towards teaching in engineering, health sciences, biology, chemistry, physics, etc. Bibliometric tools were used to analyze the evolution of educational robotics as an element that contributes to the improvement of teaching and involvement in teaching methods used by teachers.
Robots in nursing education: a bibliometric analysis
Authors: Romero A , La Hoz J De , González J D
Published: December 2019

Laboratory experimentation using robotics plays an essential role in nursing education. This research to answer the question, How do the use of robots by the nursing students influence the effectiveness, the usefulness, and user friendliness of, their satisfaction with, this kind of education technology for a clinical experience. Furthermore, this technology provide additional benefits such as supporting distance learning, improving lab accessibility to handicapped people, and increasing safety for dangerous experimentation. This paper analyzes the literature on robotics labs in nursing education from its beginnings to 2019, identifying the most influential publications, the most researched topics, and how the interest in those topics has evolved along the way. To do so, bibliographical data gathered from ISI Web of Science, Scopus and MedLine have been examined using two prominent bibliometric approaches: science mapping and performance analysis prominent bibliometric approaches: science mapping and performance analysis.
On Convergence of Difference Approximations to Problems of Optimal Control in the Coefficients of Elliptic Equations with Mixed Derivatives and Unbounded Non-Linearity
Authors: Manapova Aigul
Published: December 2019

This paper deals with optimization problems for elliptic PDEs with mixed derivatives and nonlinearities of unlimited growth in the coefficients (i.e. the conditions imposed on the equation coefficients are assumed to hold only in a neighborhood of the exact solution to the original problem). The controls are contained in the leading part of the state equation. Convergence and approximation analysis for the optimization problems is investigated. The convergence of the approximations with regard to the state, functional and control is established, the approximations are regularized.
Quantitative analysis of lexical complexity in contemporary Russian novels
Authors: Maslennikova Yu S , Abramov A V
Published: December 2019

This research presents a set of methods for measuring the lexical complexity against the culture at large. We applied a range of statistical measures upon a set of texts. For the analysis, we selected 50 famous Russian novels of the 20th century based on their historical and generic variety. The main approach consists of the comparison of the relative frequency of a work’s words against the Google Books dataset. This dataset represents a remarkable resource, with the Russian Google Books corpus in the period 1800 - 2012, containing approximately 4.7 billion 1-grams. Relative frequencies distribution for a novels words were compared with frequencies of Google Books corpus of different years using JensenShannon divergence, KullbackLeibler divergence and other information measures. Also, so-called a Flesch reading ease scale was calculated, such measure was used in similar research of modern English fiction. It was shown that the lexical complexity of individual texts should be measured against the culture at large. It was found that a writer who commonly seems to be difficult, verbose or notional, can in fact use language that is more ‘common’ (relative to the culture at large) than any other texts.
Far surface gravity waves fields under unstable generation regimes
Authors: Bulatov V V , Vladimirov Yu V
Published: December 2019

The problem of constructing uniform asymptotics of surface perturbations far fields from a localized harmonic source in the flow of a heavy homogeneous fluid of infinite depth is considered. It is shown that the wave pattern of excited long-range fields is, for certain generation parameters, a system of hybrid wave perturbations which simultaneously exhibit the properties of the following two types: annular-type (transverse) and wedge-type (longitudinal) waves. Specific features of the phase structure and wave fronts are studied. Uniform asymptotics of the solutions which describe the hybrid surface wave perturbations at a far distance from the harmonic source are constructed.
On linear stability of shear flows of an ideal stratified fluid: research methods and new results
Authors: Gavrilieva A A , Gubarev Yu G
Published: December 2019

The results, that obtained by the spectral method with use of integral relations for the problem of linear stability of steady-state shear plane-parallel flows of an inviscid stratified incompressible fluid in the gravity field with respect to plane perturbations in the Boussinesq approximation and without it, are specified, complemented and developed by the most powerful analytical method of the modern mathematical theory of hydrodynamic stability – the second (or direct) Lyapunov method. In both case, the new analytical method made it possible to prove that given steady-state flows of stratified fluid are absolutely unstable in theoretical sense with respect to small plane perturbations and to obtain the sufficient conditions for practical linear instability of considered flows. The illustrative analytical examples of given steady-state flows and small plane perturbations as normal waves imposed on them are constructed. Using the asymptotic method, it is proved that constructed perturbations grow in time irrespective of the fact whether the Miles-Howard and the Miles-type theorems are valid or not.
Solution of model boundary value problems on oscillations of mechanical systems with moving boundaries by the duhamel method
Authors: Litvinov Vladislav L.
Published: December 2019

The Kantorovich – Galerkin method in conjunction with the Duhamel method is considered as applied to solving problems describing the oscillations of visco–elastic objects with conditions on moving boundaries. The mathematical formulation of the problem includes an inhomogeneous partial differential equation with respect to the desired displacement function, inhomogeneous boundary and initial conditions. By introducing a new function into the problem, the boundary and initial conditions are reduced to homogeneous. The solution is made in dimensionless variables with an accuracy of the second order of smallness with respect to small parameters characterizing the velocity of the boundary and viscoelasticity. Using the Kantorovich – Galerkin method and the Duhamel method, an approximate solution of the problem of forced longitudinal oscillations of a viscoelastic rod of variable length is found.
About the algorithm for calculating the final probabilities
Authors: Mastikhin A.V , Mastikhina A. A
Published: December 2019

We consider a Markov process with continuous time and a countable number of states, known as the (general) Bartlett–Mac-Kendrick epidemic. Kolmogorov’s equation for the exponential (double) generating function of the final probabilities is a hyperbolic partial differential equation. Its solution requires the calculation of the final probabilities for trajectories specifying one of the boundary conditions. It is shown that the desired trajectory is described as the Dick paths, enumerated by Catalan numbers. For arbitrary trajectories of the final probabilities of the general epidemic process, a calculation algorithm based on the contex-free grammar is proposed. The enumerative problem is solved.
The algorithm for generation of structured grids in deformed volumes of revolution
Authors: Anuchina A I , Artyomova N A , Gordeychuck V A , Ushakova O V
Published: December 2019

For the volume of revolution deformed by another volume of revolution, a grid generation algorithm is suggested. The algorithm is designed for multimaterial hydrodynamic simulation and for solving other physical and engineering problems. The algorithm represents the non-stationary procedure generating three-dimensional structured grids in domains with moving boundaries. The algorithm is developed within the variational approach for constructing optimal curvilinear grids. The volume of revolution is obtained by the rotation about the axis through 180° of a plane generatrix curve consisting of straight line segments and arcs of circles. The non-stationary algorithm is the iterative process at each stage of which the deformation of a grid and then its optimization are carried out. The deformation of a grid is implemented within the geometrical approach, and the optimization of a grid within the variational approach. Iterations are continued until the necessary deformation is reached. The algorithm is realized in the computer code written in C++.
Mathematical modeling of free-surface flows using multiprocessor computing systems
Authors: Gushchin V A , Kondakov V G
Published: December 2019

In this article the results of series of works concerning free-surface flows in liquid medium. Two models were considered: free-surface flows of homogeneous liquid and flows in density stratified liquid. For first model two problems were solved: fluid fluctuations in the container and the occurrence of an undular bore upon collision of a one-way flow with a wall. For second model also was performed test: collapse of homogeneously mixed spot of fluid in the stratified medium. For every test examples satisfactory results were obtained, comparable analysis was carried out whether it corresponds to analytic results.
Calculation of current distribution in tungsten plate under exposure to a pulsed electron beam
Authors: Lazareva G.G. , Arakcheev A.S. , Popov V.A. , Maksimova A.G. , Kapina E.S.
Published: December 2019

In the mathematical model of melting of a tungsten plate exposed to a pulsed electron beam, the calculation of the current distribution in the medium is added. The model takes into account the heterogeneity of the resistivity. This enables modeling of non-uniform heated material. The current is expected to spread into the depth due to the increased resistance of the heated part. Changing the thickness of the tungsten plate, one can increase the current density in the melt. The calculation results for parameters corresponding to those used on the BETA facility at BINP SB RAS show that no current concentration occur. The Ampere force is not large enough for the rotation observed in the experiments.
Estimation of parameters of gas diffusion in models of microtransfactions of different type by the method of molecular dynamics
Authors: Antonov M.Yu. , Popinako A.V. , Grigoriev A.V. , Nikolaev I.N.
Published: December 2019

Estimation of gas transport parameters in organic nano-porous materials, such as kerogens, is important for understanding the fundamentals of the processes that co-produce natural gas. In this regard, the description and numerical parameterization of the processes of transfer of components of natural gas occurring at the micro level in organic nano-porous materials is of interest both from fundamental and practical points of view, including the search for possible ways to optimize the yield of natural gas and boost recoil. The purpose of this study is to study the methods of molecular modeling and the molecular dynamics of the mechanisms of gas transport in structures that mimic organic nano-porous materials, and the numerical evaluation of mass transfer parameters.
Digital twins of multiscale 3D heterogeneous geological objects: 3D simulations and seismic imaging of faults, fractures and caves
Authors: Cheverda Vladimir , Lisitsa Vadim , Protasov Maksim , Reshetova Galina , Glinsky Boris , Chernykh Igor , Merzlikina Anastasiya , Volyanskaya Victoria , Petrov Denis , Melnik Artjem , Shilikov Valery
Published: December 2019

Numerical simulation of seismic waves’ propagation and imaging in a three-dimensional multiscale geological media is one of the main trends in the development of modern geophysics. We present the work flow for construction of the 3D digital twin of some real geological object. This object is cavernous fractured carbonate reservoir near the Riphean roof. One of the main features of this object is the presence of the family of faults filled with tectonic breccia. To simulate them, in particular, their interiors and surrounding damaged areas, we simulate paleotectonic processes with the use of 3D discrete elements technique. This simulation we do by GPU parallelization.

Next, when the fine digital geological model is done, we perform 3D finite-difference simulation of the seismic waves’ propagation and get the full 3D synthetic data set. To do this simulation we use an original technique based on local grid refinement in time and space. To be able to deal with huge amount of input/output data we use High-Performance Computing (HPC) systems with parallel architecture and hybrid parallelization strategy by simultaneous use of MPI and OpenMP.

The final step is validation of our original multiscale algorithm for seismic imaging, which suppresses specular reflection, but accumulates weak scattered/diffracted waves. This approach opens the way to the reconstruction of subseismic geological objects, like fractures, fracture corridors and clusters of caves. To construct these images we use HPC with parallel architecture and MPI+OpenMP programming.
Algorithm for restoration of friction power in drum brake device with a layer from the compositional material on temperature data
Authors: Kondakov A S
Published: December 2019

A quasilinear two-dimensional mathematical model of the thermal process in a drum braking device is considered, taking into account the rotational motion of the brake cylinder. The basic heat conduction equations and the algorithm for solving by method of conjugate gradients of the boundary inverse heat conduction problem to restore the friction power between the brake pad and the cylinder on temperature data are given.
Parallel computing applied to the molecular dynamics simulations
Authors: Malyshev Victor L. , Moiseeva Elena F.
Published: December 2019

This paper discusses the use of high-performance algorithms for modeling the dynamics of dispersed systems using the method of molecular dynamics. Large-scale modeling, which makes it possible to determine various thermodynamic parameters and control the processes of phase transformations, requires consideration of a large number of particles, which imposes significant restrictions on the computational capabilities of the system. In work various problems of dynamics of disperse systems are considered. To solve the problems posed by the authors, a specialized data structure was developed, which reduces the computational complexity of the algorithm from quadratic to linear. The specificity of the molecular dynamics method makes it possible to achieve significant acceleration when using computations at heterogeneous stations equipped with a central processing unit (CPU) and graphic processing units (GPU). The authors showed that the presented technique can be effectively used for solving problems related to modeling processes occurring in areas with characteristic sizes of tens of nanometers on personal computers equipped with one or more GPUs.
Virtual stream computing systems with a fuzzy computing environment
Authors: Myshev A.V
Published: December 2019

The paper reveals the architecture (structure) of virtual stream computing systems with a fuzzy computing environment (closure conditions, constraints, exchanges, small scales and information uncertainty). The system assumes that hardware-software, computing and information-intellectual functions of such systems can actually be implemented and implemented in the form of hardware, software, brainware products for supercomputer technologies of mathematical modelling. Such products allow to obtain more adequate, reliable, meaningful and valuable results in the computational technologies of mathematical modeling. . This is due to the fact that the logic circuits of algorithms and procedures of computational technologies include an information system for referencing coordinates and checking the results of calculations in a fuzzy (diffuse) computing environment based on the principles of locality and specifying the model of the information environment for generating a result.
Block finite-element approach to building refined models of layer-by-layer analysis of the stress-strain state of three-layer irregular shells
Authors: Bakulin V N
Published: December 2019

This work offers a block finite element approach to building refined models of layer-by-layer analysis of stress-strain state of three-layer generally irregular cylindrical shells.
GPU-accelerated discrete element modeling of geological faults
Authors: Lisitsa V. , Tchebverda V. , Volianskaia V.
Published: December 2019

In this paper, we present an original algorithm for the numerical simulation of tectonic movements and the related formation of geological faults. The approach is based on the use of Discrete Element Method, where the geological media is represented as an agglomeration of discrete particles which interact as elastic, visco-elastic, or elasto-plastic bodies. This approach naturally allows accounting for large deformations and discontinuities in the geological media; thus, allows simulation of faults formation. Implementation of the algorithm is based on the use of Graphical Processor Units. The Discrete Element Method requires a high number of floating point operations and logical operations per a single particle (degree of freedom) per time step; whereas the number of memory access operations is relatively low. Thus, the use of GPUs decreases the computational time substantially.
Modeling of burden at automated strength calculation of mobile vehicles supporting structures
Authors: Tokareva M , Zubkova T
Published: December 2019

A method, its algorithmic and software implementation, based on the use of the Ritz variational principle, which allows to calculate the values of stresses, displacements, reactions at the points of interest to the researcher, has been developed to simulate static loading when calculating the strength of structures consisting of flat elements This provides an opportunity to reduce the complexity and timeline of final testing of the supporting structures of mobile vehicles.
Investigation of thermal properties of Al1050/SS304 sandwich composite sheet by using a numerical, analytical and experimental approach
Authors: Takalkar Atul S , Mailan Chinnapandi Lenin Babu
Published: December 2019

The utilization of the sandwich composite sheets for the specific industrial application depends upon its material properties. The present study investigates the mechanical and thermal properties of Al1050/SS304 sandwich composite sheets which could be used for the manufacturing of automobile sheet metal components such as a car body. The XRD (X-ray powder diffraction) and FTIR (Fourier-transform infrared spectroscopy) are performed to investigate the molecular structural arrangement and adhesive bonds whereas the composite wall test is performed to investigate the thermal conductivity by using different approaches. The experimental approach integrated with the analytical approach is utilized to validate the obtained thermal conductivity using a numerical approach. The thermal conductivity of 2.84 W mK−1 is obtained by using a numerical approach which is in good correlation with the experimental results.
Double-pulse femtosecond laser ablation for synthesis of ultrasmall carbon nanodots
Authors: Nguyen Vanthan , Zhao Na , Yan Lihe , Zhong Peng , Nguyen Van Canh , Le Phuoc Huu
Published: December 2019

Carbon nanodots (C-dots) with ultrasmall size possessing large surface-to-volume ratio are expected to improve their performance in sensing and catalytic applications. Here, we present a simple strategy to synthesis ultrasmall C-dots using double-pulse femtosecond laser ablation in solution. The size of C-dots reaches minimum value of ∼1 nm when the delay between the pulses was approaching the electron-ion relaxation time. In this case, the mean sizes of C-dots in double-pulse ablation are even smaller than that obtained in single-pulse ablation with the same laser fluence due to the suppression of rarefaction wave by the shock wave created by the second pulse. Furthermore, abundant functional groups are created on the surface of C-dots in double-pulse ablation because of reheating the nascent ablated materials by the second pulse. These results demonstrate that the double-pulse technique is therefore an effective strategy beyond single-pulse ablation to synthesis ultrasmall C-dots with abundant surface functional groups as well as other nanoparticle for catalytic and sensing applications.
Women miss out on high-profile awards
Authors: Allen Michael
Published: December 2019

Women are under-represented in senior positions within scientific societies and are disproportionately overlooked for high-profile society awards.
Towards a fusion economy
Authors: Chapman Ian
Published: December 2019

Ian Chapman, head of the Culham Centre for Fusion Energy (CCFE) in Oxfordshire, UK, talks to Michael Banks about how the lab is handling the uncertainty of Brexit and building for the future
Movie misdemeanours
Authors: Viti Eugenia , Viti Ivan
Published: December 2019

Brother-and-sister duo Eugenia Viti and Ivan Viti explore the difference between how physics is sometimes shown on film and the reality off screen – can you name the two film bloopers depicted and the one that got the science right?
Changes in land use/land cover and net primary productivity in the transboundary Ili-Balkhash basin of Central Asia, 1995–2015
Authors: Qi Jiaguo , Tao Shiqi , Pueppke Steven G , Espolov Tlektes E , Beksultanov Marat , Chen Xi , Cai Xiumin
Published: December 2019

Using remotely sensed data, we documented changes in land use/land cover (LULC) from 1995 to 2015 and net primary productivity (NPP) from 2000 to 2014 in Central Asia’s 415,048 km2 Ili-Balkhash Basin (IBB). This basin, which is shared by China and Kazakhstan, is in the midst of significant socioeconomic transformation due to the collapse of the Soviet Union, the emergence of Kazakhstan, and the economic rise of China. Grazing land covered 82.4% of the IBB in 1995; water bodies and bare land were the only other LULC categories occupying more than 3% of the basin’s area. Changes in LULC were most evident on the Chinese side of the border, where crop production areas increased and grazing areas decreased between 1995 and 2015. The area of irrigated cropland in China grew by nearly 30%, primarily in the upper Tekes River valley and along the Ili River near the border with Kazakhstan. In contrast, the irrigated lands in Kazakhstan shifted geographically during this period, but the extent did not change. Expansion of wetlands and permanent water bodies, which occupied 2.1 to 2.9% and 4.6 to 4.7%, respectively, of the IBB in 1995 and 2015, was associated with accretion of Lake Balkhash and Kapchagai Reservoir in Kazakhstan and the construction of new reservoirs in China. NPP of the basin approached 700 g C m−2/year in a few areas but was generally less than half this level and characterized by a declining trend except in highly productive irrigated areas of dense, stable vegetation. NPP decreases of more than −10 g C m−2/year were apparent in mountainous and upland areas, as well as broad band of grassland and cropland in Kazakhstan. Areas surrounding Lake Balkhash were characterized by unstable to moderately stable, often sparse vegetation.
Energy use for urban water management by utilities and households in Los Angeles
Authors: Porse Erik , Mika Kathryn B , Escriva-Bou Alvar , Fournier Eric D , Sanders Kelly T , Spang Edward , Stokes-Draut Jennifer , Federico Felicia , Gold Mark , Pincetl Stephanie
Published: December 2019

Reducing energy consumption for urban water management may yield economic and environmental benefits. Few studies provide comprehensive assessments of energy needs for urban water sectors that include both utility operations and household use. Here, we evaluate the energy needs for urban water management in metropolitan Los Angeles (LA) County. Using planning scenarios that include both water conservation and alternative supply options, we estimate energy requirements of water imports, groundwater pumping, distribution in pipes, water and wastewater treatment, and residential water heating across more than one hundred regional water agencies covering over 9 million people. Results show that combining water conservation with alternative local supplies such as stormwater capture and water reuse (nonpotable or indirect potable) can reduce the energy consumption and intensity of water management in LA. Further advanced water treatment for direct potable reuse could increase energy needs. In aggregate, water heating represents a major source of regional energy consumption. The heating factor associated with grid-supplied electricity drives the relative contribution of energy-for-water by utilities and households. For most scenarios of grid operations, energy for household water heating significantly outweighs utility energy consumption. The study demonstrates how publicly available and detailed data for energy and water use supports sustainability planning. The method is applicable to cities everywhere.
Groundwater extraction may drown mega-delta: projections of extraction-induced subsidence and elevation of the Mekong delta for the 21st century
Authors: Minderhoud P S J , Middelkoop H , Erkens G , Stouthamer E
Published: December 2019

The low-lying and populous Vietnamese Mekong delta is rapidly losing elevation due to accelerating subsidence rates, primarily caused by increasing groundwater extraction. This strongly increases the delta’s vulnerability to flooding, salinization, coastal erosion and, ultimately, threatens its nearly 18 million inhabitants with permanent inundation. We present projections of extraction-induced subsidence and consequent delta elevation loss for this century following six mitigation and non-mitigation extraction scenarios using a 3D hydrogeological model with a coupled geotechnical module. Our results reveal the long-term physically response of the aquifer system following different groundwater extraction pathways and show the potential of the hydrogeological system to recover. When groundwater extraction is allowed to increase continuously, as it did over the past decades, extraction-induced subsidence has the potential to drown the Mekong delta single-handedly before the end of the century. Our quantifications also disclose the mitigation potential to reduce subsidence by limiting groundwater exploitation and hereby limiting future elevation loss. However, the window to mitigate is rapidly closing as large parts of the lowly elevated delta plain may already fall below sea level in the coming decades. Failure to mitigate groundwater extraction-induced subsidence may result in mass displacement of millions of people and could severely affect regional food security as the food producing capacity of the delta may collapse.