?
Exact solution for 1D deep bed filtration with particle capture by advection and dispersion
International Journal of Non-Linear Mechanics. 2021. Vol. 137. Article 103830.
Kuzmina L., Osipov Y. V.
We consider a one-dimensional (1D) non-linear 2x2 hyperbolic problem of suspension-colloidal-nano transport
in porous media, so-called deep bed filtration. The particle capture rate is proportional to the overall
particle flux, which includes dispersion. The captured-particle concentration dependency on the proportionality
coefficient, which is typical for large captured concentrations, causes the non-linearity of the problem.
However, the 1D initial–boundary value problem allows for an exact solution. The introduction of the Riemann
invariant converts the 2x2 system into a scalar quasi-linear hyperbolic equation, which is implicitly solved
using the method of characteristics. The non-linear equation for particle capture rate yields a limited travelling
wave that approximates the exact solution for the initial–boundary problem.
Kuznetsov A. P., Sataev I. R., Stankevich N., Chaos 2026 Vol. 36 No. 8 Article 083131
A radio-physical system, namely, a two-mode van der Pol generator, is considered. It is shown that this system demonstrates two types of chaos: with one and two zero Lyapunov exponents. The regions of the second type of chaos are surrounded by bifurcation lines of invariant tori doubling. Quasi-periodic structures of various shapes are embedded within ...
Added: August 30, 2026
Shirokov N. A., Rozenblum G., Israel Journal of Mathematics 2026 P. 1–30
We establish that a generalized H\¨older continuous function on an (m−2)-Ahlfors regular compact set in Rm can be approximated by solutions of an elliptic equation, with the rate of approximation determined by the continuity modulus of the function ...
Added: August 29, 2026
Avdoshin S.M., Patrushev K. A., Proceedings of the Institute for System Programming of the RAS 2026 No. 4 часть 2 P. 245–256
The cardinality-constrained Markowitz problem is NP-hard and traditionally solved with commercial MIQP solvers. Following the 2022 export restrictions that rendered both commercial MIQP software and cloud quantum platforms (IBM Quantum, D-Wave Leap) inaccessible from the Russian Federation, practitioners require open-source alternatives. This paper systematically compares three solver families for the discrete mean-variance problem: two open-source ...
Added: August 27, 2026
Zaikin A., Vlasenko D., Zakharov D. et al., Diagnostics 2026 Vol. 16 No. 17 P. 1–15
Background/Objectives: Synolitic graphs (SGs) were developed for task-based fMRI, where
edge weights encode the discriminative power of pairwise regional features; whether similar
information can be recovered from resting-state data was untested. We benchmarked
SGs for autism spectrum disorder (ASD) classification using the multisite ABIDE-I dataset
(871 subjects: 403 subjects with ASD, 468 typical controls; 17 sites; CC200 atlas). Methods:
Using ...
Added: August 27, 2026
Melnikov I., Pelinovsky E., Nonlinear Dynamics 2026 No. 114 Article 934
Pyramidal solitons (solitons with more than two inflection points) of the generalized Korteweg–de Vries (KdV) equation are investigated. Necessary and sufficient conditions for the existence of such structures are presented. Within the framework of the generalized Gardner equation — the simplest model that admits pyramidal solitons as solutions — it is shown that these solutions ...
Added: August 27, 2026
Тула: Тульский государственный педагогический университет им. Л.Н. Толстого, 2025.
Сборник содержит материалы, представленные на XXIV Международной конференции «Алгебра, теория чисел, дискретная геометрия и многомасштабное моделирование: современные проблемы, приложения и проблемы истории», посвящённой 110-летию со дня рождения академика Юрия Владимировича Линника и 110-летию со дня рождения профессора Андрея Борисовича Шидловского и 80-летию со дня рождения профессора Геннадия Ивановича Архипова. Материалы конференции будут полезны научным работникам, ...
Added: August 27, 2026
Nesterenko A., Чирский В. Г., Матвеев В. Ю., Чебышевский сборник 2026 Т. 27 № 2 С. 118–127
The article presents the results of a practical study of the statistical properties of some sequences that are values of functions of a special type. ...
Added: August 26, 2026
Eduard Sopin, Nazarin A., Begishev V. et al., IEEE Transactions on Vehicular Technology 2026 Vol. 75 No. 6 P. 10995–11007
Aimed at rate-greedy applications having extreme requirements for the data rate at the air interface, 5G New Radio (NR) systems may experience problems when the number of user equipment (UE) in the coverage of the cell increases due to limited capacity of the physical downlink control channel (PDCCH).The aim of this study is to explore ...
Added: August 26, 2026
Блудов М. В., Journal of Fixed Point Theory and Applications 2026 No. 28 Article 73
In this paper, we study a construction of homotopy invariants of open or closed covers, where the homotopy class is defined relative to a pair (V, r), with V a finite set of points in and r a point in the interior of their convex hull. We show that the simplicial complex of non-balanced subsets associated with (V, r) has the homotopy ...
Added: August 25, 2026
L.I. Kuzmina, Osipov , Y. V., Kolokoltseva, T. N., Advances in Water Resources 2026 Vol. 213 Article 105335
We study 1D transport of mobilized particles, detached from the solid matrix, in porous media (so-called fines migration). Three types of colloidal-suspension flow models are considered: (i) averaged model for multicomponent colloids with distributed properties; (ii) flow of binary colloids with interacting particles; (iii) discrete system for multicomponent low-concentration colloid. These models account for distributed ...
Added: August 25, 2026
Liudmila I. Kuzmina, Osipov, Y. V., International Journal for Computational Civil and Structural Engineering 2026 Vol. 22 No. 2 P. 138–148
Modeling the transport and sedimentation of small particles of suspensions and colloids in porous rocks is an important problem in subsurface hydromechanics. Particles entrained in fluid are transported and retained in the rock pores. The filtration process is determined by the number and size of pores and is characterized by porosity—the ratio of the void ...
Added: August 25, 2026
L.I.Kuzmina, Osipov Y. V., Mathematical notes, ISSN 0001-4346 2025 Vol. 116 No. 6 P. 1251–1261
We consider the displacement of oil by water with active chemical reagents in porous media. A one-dimensional model of reagent transport and deposition is defined by a hyperbolic system of first-order equations. The purpose of the article is to find the conditions for the existence of a continuous solution with discontinuous boundary and initial conditions. ...
Added: August 25, 2026
Лукьяненко Д. В., Ragimova A., Мухорина А. et al., European Physical Journal: Special Topics 2026 P. 1–24
Electronic health records (EHRs) contain vast volumes of clinical information that encode complex relationships between diseases. Traditional approaches to the analysis of interrelated or co-occurring diseases have focused on pairwise associations between diagnoses, missing the higher-order structures that characterise multimorbid patients. The present paper offers a narrative review of existing statistical, machine-learning, and artificial intelligence ...
Added: August 20, 2026
Chernov A., European Journal of Mathematics 2026 Vol. 12 Article 48
An induced additive action on a projective variety is a regular action of the group G_a^n on X in P^n with an open orbit that can be extended to a regular action on P^n. Such actions are known to correspond to pairs (A, U), where A is a local algebra and U is a generating subspace lying in the maximal ideal. This paper ...
Added: August 19, 2026
IEEE, 2025.
Dynamics of Systems, Mechanisms and Machines (Dynamics) ...
Added: August 19, 2026
Vlasenko D., Saranskaia I., Zakharov D., European Physical Journal: Special Topics 2026 P. 1–16
Hypergraphs provide a natural framework for representing neurophysiological interactions distributed across sets of sensors. A key methodological question is how hyperedges should be defined from frequency-resolved electroencephalography/magnetoencephalography (EEG/MEG) data. We demonstrate a construction strategy in which hyperedges are obtained from canonical coherence (caCOH), an extension of coherence that estimates coupling between multidimensional signal spaces. To ...
Added: August 18, 2026
Borisov D., Katzarkov Ludmil, Sheshmani A. et al., American Journal of Mathematics 2026 Vol. 148 No. 4 P. 1075–1101
It is shown that there are globally defined Lagrangian distributions on the stable loci of derived \mathrm{Quot}-stacks of coherent sheaves on Calabi--Yau four-folds. Dividing by these distributions produces perfectly obstructed smooth stacks with globally defined -1-shifted potentials, whose derived critical loci give back the stable loci of smooth stacks of sheaves in global Darboux form. ...
Added: August 18, 2026
Богатырев А. Б., Математический сборник 2023 Т. 214 № 3 С. 106–119
Рассматривается клеточное разбиение пространства модулей вещественных кривых рода 2 с отмеченной точкой на единственном вещественном овале. Клетки перечисляются определенными графами, веса которых описывают комплексную структуру на кривой. Показано, что стягивание ребра графа приводит к корневой особенности естественного отображения из весов графа в пространство модулей кривых. ...
Added: August 14, 2026
Богатырев А. Б., Gendron Q., Успехи математических наук 2023 Т. 78 № 1 С. 209–210
Уравнение Пелля-Абеля — это функциональное уравнение вида P²-DQ² = 1, с заданным многочленом D, свободным от квадратов, и неизвестными многочленами P и Q. Мы показываем, что пространство уравнений Пелля-Абеля с фиксированными степенями D и примитивным решением P является комплексным многообразием. Мы описываем его связные компоненты с помощью эффективно вычислимого инварианта. ...
Added: August 14, 2026
Богатырев А. Б., Transactions of the Moscow Mathematical Society 2024 Vol. 85 No. 2 P. 323–337
The best uniform rational approximation of the Sign function on two intervals separated by zero was explicitly found by E. I. Zolotarëv in 1877. The natural extension of this problem to three bands was solved by E. Stiefel in 1961. We indicate the solutions overlooked by the prominent geometer and study their properties. ...
Added: August 14, 2026
Богатырев А. Б., Успехи математических наук 2026 Т. 81 № 3(489) С. 159–160
Предложена простая и эффективно реализуемая формула для изменения абелевых интегралов (включая их периоды) при вариации образующих классической группы Шоттки, представляющей риманову поврехность. ...
Added: August 14, 2026
Shvartsburg A. B., Artekha S. N., N.S. Artekha, Journal of Applied Physics 2020 Vol. 128 Article 024901
The problem of the emergence of wave dispersion due to the heterogeneity of a transmission line is considered. An exactly solvable model helps us to better understand the physical process of a signal passing through a non-uniform section of the line and to compare the exact solution and solutions obtained using various approximate methods. Based ...
Added: May 17, 2023
Yelizarov (Elizarov) A. A., Nazarov I., Skuridin A. et al., , in: SYNCHROINFO 2020 Systems of Signal Synchronization, Generating and Processing in Telecommunications.: IEEE, 2020. P. 1–4.
This paper presents a computer model of a FSS based on mushroom-shaped metamaterial. The model is based on the calculation of equivalent distributed inductance and distributed capacitance of the unit cell of the surface according to its geometric dimensions. The computer model is realized as the “META” program based on MathCAD ver.15 software and provides ...
Added: August 20, 2020