Article
Engineering, Mechanical
A. A. Basmaji, A. Fau, J. H. Urrea-Quintero, M. M. Dannert, E. Voelsen, U. Nackenhorst
Summary: This study introduces a new hp-adaptive variant of multi-element polynomial chaos expansion, which significantly reduces computational costs, improves efficiency and accuracy in high-dimensional problems. Through comparative studies on elastoplasticity in nonlinear structural analysis, it demonstrates the superiority of this method.
PROBABILISTIC ENGINEERING MECHANICS
(2022)
Article
Acoustics
Jin-bao Li, Zhong-wei Hu, Zhao-dong Xu, Ying-qing Guo
Summary: A novel high damping isolation trench is proposed to improve the efficiency of conventional isolation trench and mitigate the impact of ground-borne vibration on buildings. Viscoelastic braces in the trench dissipate energy while providing supporting force. Two types of high damping isolation trenches, U-shaped and L-shaped, are designed based on actual ancient buildings to reduce damages caused by train-induced vibration. Experimental and computational results show that the viscoelastic braces effectively reduce acceleration and velocity responses of buildings, demonstrating superiority over linear-shaped trenches.
JOURNAL OF VIBRATION AND CONTROL
(2022)
Article
Mathematics
Pavel Loskot
Summary: The paper investigates the issue of conducting correlation analysis with a large number of observations and proposes a novel class of statistical measures to reduce dimensionality. By approximating the Taylor expansion of a general multivariate scalar symmetric function, the mean value of the polynomial is calculated to be a weighted sum of statistical central sum-moments, which helps reduce the numerical complexity of linear regression in certain scenarios. The illustrative examples assume first and second order Markov processes.
Article
Engineering, Electrical & Electronic
Josef Knapp, Thomas F. Eibert
Summary: Explicit formulas are presented in this article for converting spherical wave expansions with vector basis functions and scalar expansion coefficients into spherical wave expansions with scalar basis functions and vector expansion coefficients, and vice versa. These formulas are given in terms of Wigner-3-j-symbols and derived through spherical harmonics expansions. The redundancy in the expansions with vector coefficients is utilized to find compact expansions with a minimum order. The correctness of all the expansions is verified using a computer code, showing a high level of agreement between the near and far fields.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Computer Science, Theory & Methods
Mima Stanojkovski
Summary: We generalize subspace codes using codes of modules over finite commutative chain rings. We introduce a new class of Sperner codes and prove their optimality in different cases using results from extremal combinatorics. Furthermore, we demonstrate the connection with Bruhat-Tits buildings and show that our codes are analogous to spherical codes in the Euclidean sense.
DESIGNS CODES AND CRYPTOGRAPHY
(2023)
Article
Mathematics
Tali Kaufman, Ori Parzanchevski
Summary: This paper investigates the power operation problem of high-dimensional expander graphs, and defines a new power operation method that uses geodesic walks on quotients of Bruhat-Tits buildings. Applying this operation can obtain expander graphs of higher degrees, and the combinatorial study of flags of free modules over finite local rings proves their excellent expansion properties in the power complex.
INTERNATIONAL MATHEMATICS RESEARCH NOTICES
(2022)
Article
Polymer Science
Chia-Cheng Chu, Pai-Yi Hsiao
Summary: This article proposes a two-stage model to explain the phenomena of chain expansion released from a confining cavity. In the first stage, the chain is assumed to expand as a sphere, while in the second stage it expands like a coil. The kinetic equations for the variation of chain size are derived in the two stages by balancing the rate of the free energy change with the rate of energy dissipation. Langevin dynamics simulations are performed to examine the theory. The simulation results support the theory and reveal that the expansion process is dominated by the second stage, confirming the predicted curve for coil expansion.
Article
Engineering, Multidisciplinary
Pulkit Kumar, Moumita Mahanty, Abhishek Kumar Singh, Amares Chattopadhyay
Summary: This study analyzes the propagation characteristics of shear waves in a spherical layered structure consisting of isotropic sandy material and a concentric layer of transversely isotropic sandy material. The dispersion relation is obtained using analytical treatment and numerical computations are used to illustrate the influence of different parameters on dispersion curves. The impact of anisotropy is exposed through a comparative study with isotropic materials.
APPLIED MATHEMATICAL MODELLING
(2022)
Article
Engineering, Geological
Jim Shiau, Bishal Chudal, Suraparb Keawsawasvong
Summary: This study explores the three-dimensional collapse stability of different shapes of underground cavities and investigates the combined impacts of soil cover, surcharge pressure, soil weight, and internal pressure using dimensionless parameters.
Article
Astronomy & Astrophysics
Andrea Giusti, Valerio Faraoni
Summary: The concept of turnaround surface in an accelerating universe has been generalized to accommodate arbitrarily large deviations from spherical symmetry, bridging the gap between ideal theoretical literature and real-world observations. An analytical application of this concept has been used to characterize small deviations from spherical symmetry, extending previous results to scalar-tensor gravity.
Article
Energy & Fuels
Jibiao Wang, Dan Wang, Yuan Chu, Sujuan Zha, Minxian Wu, Changhai Liu, Wenchang Wang, Naotoshi Mitsuzaki, Shuyong Jia, Zhidong Chen
Summary: This study successfully solves the low conductivity issue of cobalt-based oxides in supercapacitors by constructing heterogeneous structural materials. The synthesized NiCoOX@NiCo LDH heterostructure exhibits a high specific capacitance and capacitance retention rate, as well as a high energy density and cycle life in the assembled capacitors.
JOURNAL OF ENERGY STORAGE
(2023)
Article
Physics, Applied
Chun-Lin Lin, Tso-Wei Chen, Yao-Jen Chang, Hideyuki Murakami, Seiji Mitani, An-Chou Yeh
Summary: A metastable face-centered cubic High Entropy Alloy exhibited significantly suppressed thermal expansion coefficient and stable Young's modulus over a wide temperature range. Both Invar and Elinvar effects were present in the alloy, and its metastability led to abrupt changes in thermal expansion behavior associated with phase transitions. Additionally, a magnetic second-order phase transition resulted in a significant magnetic entropy difference in the alloy.
APPLIED PHYSICS LETTERS
(2021)
Article
Engineering, Multidisciplinary
Yi Gao, Yang Jiao, Yongming Liu
Summary: This paper introduces a novel methodology for probabilistic material reliability analysis considering fine-scale microstructure stochasticity, addressing challenges of handling uncertainties and dimensionality for probabilistic solvers. By utilizing analytical and hierarchical uncertainty quantification methods and forming a probabilistic solver with adjoint first-order reliability method, the proposed approach demonstrates high efficiency in solving high-dimensional material reliability problems.
APPLIED MATHEMATICAL MODELLING
(2021)
Article
Engineering, Civil
Xingyan Fan, Lianghao Zou, Jie Song, Shuguo Liang, Min Yu
Summary: The present study proposes a novel three-dimensional forced vibration wind tunnel test system that can drive the model to vibrate in three dimensions while maintaining more realistic mode shapes. The test results show that the system performs well, providing stable vibration amplitude, frequency, and phase angle in all three directions. The proposed system provides an alternative method for determining the aeroelastic properties of high-rise buildings.
JOURNAL OF WIND ENGINEERING AND INDUSTRIAL AERODYNAMICS
(2023)
Article
Astronomy & Astrophysics
Bita Farsi, Ahmad Sheykhi, Mohsen Khodadi
Summary: Using the spherical collapse formalism, we study the linear evolution of matter overdensity in energy-momentum-squared gravity (EMSG), which can be seen as an extension of the ΛCDM model. We find that the modifications from EMSG have effects on the growth of perturbations in the early Universe. We discuss the role of EMSG model parameter on the evolution of matter density contrast and growth function at the level of linear perturbations.
Article
Computer Science, Theory & Methods
Alexander Lubotzky, Zur Luria, Ron Rosenthal
DISCRETE & COMPUTATIONAL GEOMETRY
(2019)
Article
Mathematics
Alexander Lubotzky, Jason Fox Manning, Henry Wilton
COMMENTARII MATHEMATICI HELVETICI
(2019)
Article
Mathematics
Nir Avni, Alexander Lubotzky, Chen Meiri
INVENTIONES MATHEMATICAE
(2019)
Article
Mathematics
Mikhail Belolipetsky, Alexander Lubotzky
ISRAEL JOURNAL OF MATHEMATICS
(2019)
Article
Mathematics
Gady Kozma, Alexander Lubotzky
BULLETIN OF MATHEMATICAL SCIENCES
(2019)
Article
Mathematics
Alexander Lubotzky, Tyakal Nanjundiah Venkataramana
ALGEBRA & NUMBER THEORY
(2019)
Article
Mathematics
Oren Becker, Alexander Lubotzky, Andreas Thom
DUKE MATHEMATICAL JOURNAL
(2019)
Article
Mathematics
Oren Becker, Alexander Lubotzky
JOURNAL OF FUNCTIONAL ANALYSIS
(2020)
Article
Mathematics
Montserrat Alsina, Dimitrios Chatzakos
JOURNAL OF NUMBER THEORY
(2020)
Review
Multidisciplinary Sciences
Alexander Lubotzky, Ori Parzanchevski
PHILOSOPHICAL TRANSACTIONS OF THE ROYAL SOCIETY A-MATHEMATICAL PHYSICAL AND ENGINEERING SCIENCES
(2020)
Article
Mathematics, Applied
E. Lubetzky, A. Lubotzky, O. Parzanchevski
JOURNAL OF THE EUROPEAN MATHEMATICAL SOCIETY
(2020)
Article
Mathematics, Applied
Arie Levit, Alexander Lubotzky
Summary: In this study, it is proven that all invariant random subgroups of the Lamplighter group L are co-sofic. This leads to the conclusion that L is permutation stable, serving as an example of an infinitely presented group. The proof presented here can be generally applied to all permutational wreath products of finitely generated abelian groups, relying on the pointwise ergodic theorem for amenable groups.
ERGODIC THEORY AND DYNAMICAL SYSTEMS
(2022)
Article
Mathematics
Marston Conder, Alexander Lubotzky, Jeroen Schillewaert, Francois Thilmany
Summary: This paper introduces the concept of highly regular graphs and uses the theory of Coxeter groups and abstract regular polytopes to construct such graphs. By constructing highly regular quotients of the 1-skeleton of the associated Wythoffian polytope with finite vertex links, an infinite family of expander graphs is obtained. This method solves the problem proposed by Chapman, Linial and Peled.
TRANSACTIONS OF THE AMERICAN MATHEMATICAL SOCIETY
(2022)
Article
Mathematics
Alexander Lubotzky, Izhar Oppenheim
JOURNAL D ANALYSE MATHEMATIQUE
(2020)
Article
Mathematics, Applied
Marcus De Chiffre, Lev Glebsky, Alexander Lubotzky, Andreas Thom
FORUM OF MATHEMATICS SIGMA
(2020)
