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Shearless effective barriers to chaotic transport induced by even twin islands in nontwist systems

Physical Review E 2024年第4期110卷 044201页

作者： M. Mugnaine I. L. Caldas J. D. Szezech, Jr. R. L. Viana P. J. Morrison Graduate in Science Program—Physics Department of Mathematics and Statistics Department of Physics Department of Physics and Institute for Fusion Studies

For several decades now it has been known that systems with shearless invariant tori, nontwist Hamiltonian systems, possess barriers to chaotic transport. These barriers are resilient to breakage under perturbation and therefore regions where they occur are natural places to look for barriers to transport. Here we describe a kind of effective barrier that persists after the shearless torus is broken. Because phenomena are generic, for convenience we study the standard nontwist map (SNM), an area-preserving map that violates the twist condition locally in the phase space. The barrier occurs in nontwist systems when twin even period islands are present, which happens for a broad range of parameter values in the SNM. With a phase space composed of regular and irregular orbits, the movement of chaotic trajectories is hampered by the existence of shearless curves, total barriers, and a network of partial barriers formed by the stable and unstable manifolds of the hyperbolic points. Being a degenerate system, the SNM has twin islands and, consequently, twin hyperbolic points. We show that the structures formed by the manifolds intrinsically depend on period parity of the twin islands. For this even scenario the structure that we call a torus free barrier occurs because the manifolds of different hyperbolic points form an intricate chain atop a dipole configuration and the transport of chaotic trajectories through the chain becomes a rare event. This structure impacts the emergence of transport, the escape basin for chaotic trajectories, the transport mechanism, and the chaotic saddle. The case of odd periodic orbits is different: we find for this case the emergence of transport immediately after the breakup of the last invariant curve, and this leads to a scenario of higher transport, with intricate escape basin boundary and a chaotic saddle with nonuniformly distributed points.

关键词： Classical mechanics

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Optimizing Preacher Assignments Using AHC-PCA Algorithm in Kampar Regency 2

Optimizing Preacher Assignments Using AHC-PCA Algorithm in K...

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2nd IEEE International Conference on Electrical Engineering, Computer and Information Technology, ICEECIT 2024

作者： Kurniawan, Rahmad Suhada, Nuraina Sukamto Melia, Tisha Zailani Risanto, Joko Department of Computer Science Faculty of Mathematics and Natural Sciences Universitas Riau Pekanbaru Indonesia Graduate Program Universitas Islam Negeri Sultan Syarif Kasim Riau Pekanbaru Indonesia

ISBN: (纸本)9798331504373

Inefficiencies in assigning preachers for Islamic preaching activities often arise due to distant placements, leading to delays and logistical challenges. In Kampar Regency, geographical diversity intensifies this issue, resulting in suboptimal preacher placements. This study aims to optimize preacher assignments by considering distance and mosque profiles. The dataset, which includes 102 mosques and 148 preachers was obtained from the Indonesian Ulema Council in Kampar. The Agglomerative Hierarchical Clustering (AHC) algorithm was selected for its capacity to cluster data across multiple characteristics. Principal Component Analysis (PCA) was employed to reduce data dimensionality, thereby enhancing clustering outcomes. The optimization of the AHC-PCA algorithm generated an optimal clustering solution with a silhouette score of 0.625524 at three clusters. Furthermore, the elbow method also indicated that three clusters are optimal with a value of 390.234457, while the lowest Davies-Bouldin Index (DBI) score of 0.468573 was achieved with three clusters. Business Intelligence techniques visualized these clusters, providing a spatial distribution of preachers and mosques for detailed analysis. This study improves preacher assignments by reducing travel time and aligning preacher placements with mosque proximity and needs, thus enhancing the efficiency of Islamic preaching in Kampar Regency. © 2024 IEEE.

关键词： Efficiency

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Thermal modeling and monitoring of massive concrete foundations to prevent pathological manifestations

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Journal of Building Pathology and Rehabilitation 2023年第1期8卷 1-9页

作者： Vidal, Alexandre Machado, Amanda Babadopulos, Lucas Magalhães, Raquel Graduate Program in Civil Engineering (PPGEC) University of São Paulo (USP) São Paulo Brazil Graduate Program in Civil Engineering (PEC) Federal University of Ceará (UFC) Fortaleza Brazil Department of Structural Engineering and Civil Construction (DEECC) Federal University of Ceará (UFC) Fortaleza Brazil Graduate Program in Mathematics (PPG-MAT) University of São Paulo (USP) São Paulo Brazil

The increase in the scale of towers construction requires larger concrete foundations, wither for buildings or for other infrastructures such as those necessary for wind energy production. Heat generation by cement hydration, large dimensions and low heat dissipation capacity of concrete causes high internal temperatures in the foundations, which can lead to cracking due to thermal stresses at early ages or expansion due to delayed ettringite formation (DEF). This study aimed to develop and validate with experimental data a thermal simulation model of foundations for assessing the risk of pathological manifestations, track temperatures developed by the structure and investigate the effects of using fly ash (FA) and polyfunctional additive (PF) in the concrete mix, among other simulation conditions. Ansys software was used to develop a finite element model. Different calorimetric profiles were inserted as a function of the presence of FA and PF in the concrete. Real climate data was used to approximate the model to reality and to study the effect of weather conditions on the temperatures developed by the structure. The simulations showed that the replacement of Portland cement by FA reduced the maximum temperatures in the structure, and the use of PF delayed the start of heating but did not affect the maximum temperatures reached. The ambient temperature varying with time caused oscillations in the temperature of the border of the structure, in response to the heat exchanges. Wind speed affected the cooling potential and the intensity of the oscillations. Through an observation of collected data, the influence of environmental conditions on the behavior of the structure was confirmed. It was concluded that the model was able to represent the real situation well and that the control of heat exchange can aid the prevention of cracking of the massive concrete foundation. © 2023, The Author(s), under exclusive licence to Springer Nature Switzerland AG.

关键词： Delayed ettringite formation Massive foundation Thermal crack Thermal simulation

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Heterogeneous catalytic oxidative desulfurization of dibenzothiophene of metal oxide–Mg/Al layered double hydroxide

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Environmental Science and Pollution Research 2025年第13期32卷 8555-8563页

作者： Ahmad, Nur Hanifah, Yulizah Arsyad, Fitri Suryani Lesbani, Aldes Graduate School of Mathematics and Natural Sciences Faculty of Mathematics and Natural Sciences Universitas Sriwijaya Sumatera Selatan Palembang30139 Indonesia Research Center of Inorganic Materials and Coordination Complexes Universitas Sriwijaya Sumatera Selatan Palembang30139 Indonesia Research Center for Chemistry National Research and Innovation Agency Building 452 KST BJ Habibie Banten Serpong Tangerang Selatan15311 Indonesia Master Program of Material Science Graduate School Universitas Sriwijaya Sumatera Selatan Palembang30139 Indonesia

Mg/Al-TiO2 and Mg/Al-ZnO were successfully prepared for dibenzothiophene catalytic oxidative desulfurization. XRD, FTIR, TEM, and BET analyses were utilized to characterize the catalyst. In composites, the distinctive XRD patterns of precursors are still observable. FTIR spectra of the absorption bands were at 3448, 1627, 1381, 601, and 547 cm−1. The TEM pictures of the sample also revealed the almost spherical and hexagonal platelets of Mg/Al-LDH and its composite. Mg/Al LDH, Mg/Al-TiO2, and Mg/Al-ZnO had typical pore sizes of 35.78 nm, 52.81 nm, and 38.37 nm, respectively. The graph of nitrogen isotherms Mg/Al LDH, Mg/Al-TiO2, and Mg/Al-ZnO followed type IV isotherms. In addition, the conversion rates on Mg/Al-ZnO, Mg/Al-TiO2, ZnO, Mg/Al-LDH, and TiO2 were 99.34%, 99.50%, 91.20%, 96.29%, and 88.06%, respectively. This work presents alternative materials for the oxidative desulfurization of dibenzothiophene in practical applications. © The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature 2025.

关键词： Zinc oxide

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-invariant curves of genera 10 and 19

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Beiträge zur Algebra und Geometrie / Contributions to Algebra and Geometry 2024年第4期65卷 881-906页

作者： Yoshida, Yusuke Graduate School of Advanced Science and Engineering Mathematics Program Hiroshima University Higashi-Hiroshima City Japan

We study smooth curves on which the alternating group $$\mathfrak {A}_{6}$$ acts faithfully. Let $$\mathcal {V} \subset {\text {PGL}}(3, \mathbb {C})$$ be the Valentiner group, which is isomorphic to $$\mathfrak {A}_{6}$$ . We see that there are integral $$\mathcal {V}$$ -invariant curves of degree 12 which have geometric genera 10 and 19. On the other hand, if $$\mathfrak {A}_{6}$$ acts faithfully on a curve C of genus 10 or 19, then we give an explicit description of the extension $$k(C / \mathfrak {A}_{5}) / k(C / \mathfrak {A}_{6})$$ for any icosahedral subgroup $$\mathfrak {A}_{5}$$ . Using this, we show the uniqueness of smooth projective curves of genera 10 and 19 whose automorphism groups contain $$\mathfrak {A}_{6}$$ .

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MURMURATIONS AND SATO-TATE CONJECTURES FOR HIGH RANK ZETAS OF ELLIPTIC CURVES II: BEYOND RIEMANN HYPOTHESIS

arXiv

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arXiv 2025年

作者： Shi, Zhan Weng, Lin Graduate Program of Mathematics for Innovation Kyushu University Fukuoka Japan Faculty of Mathematics Kyushu University Fukuoka Japan

As a continuation of our earlier paper [6], we offer a new approach to murmurations and Sato-Tate laws for higher rank zetas of elliptic curves. Our approach here does not depend on the Riemann hypothesis for the so-called a-invariant aE{Fp;n in rank npě 3q even for the Sato-Tate law, rather, on a much refined structure, a similar version of which was already observed earlier by Zagier and the senior author of this paper in [12] when the rank n Riemann hypothesis was established. Namely, instead of the rank n Riemann hypothesis bounds ´1 ď a2E?{Fppn;n ď 1 on which our first paper is based, we use the asymptotic bounds ´1 ď aE{Fp;n2`ppnn´´1q1 ? qpp`pn´5q ď 1. Accordingly, rank n Sato-Tate law can be established and rank n murmurations can be formulated equally well, similar to the corresponding structures in the abelian framework for Artin zetas of elliptic curves. © 2025, CC BY.

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Murmurations and Sato-Tate Conjectures for High Rank Zetas of Elliptic Curves

arXiv

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arXiv 2024年

作者： Shi, Zhan Weng, Lin Graduate Program of Mathematics for Innovation Kyushu University Fukuoka Japan Graduate School of Mathematics Kyushu University Fukuoka Japan Faculty of Mathematics Kyushu University Fukuoka Japan

For elliptic curves over rationals, there are a well-known conjecture of Sato-Tate and a new computational guided murmuration phenomenon, for which the abelian Hasse-Weil zeta functions are used. In this paper, we show that both the murmurations and the Sato-Tate conjecture stand equally well for non-abelian high rank zeta functions of the p-reductions of elliptic curves over rationals. We establish our results by carefully examining asymptotic behaviors of the p-reduction invariants aE/Fp,n (n ≥ 1), the rank n analogous of the rank one a-invariant aE/Fp = 1+p−NE/Fp of elliptic curve E/Fp. Such asymptotic results are based on the counting miracle of the so-called αE/Fq,n- and βE/Fq,n-invariants of E/Fq in rank n, and a remarkable recursive relation on the βE/Fq,n-invariants, both established by Weng-Zagier in [19]. © 2024, CC BY.

关键词： Rational functions

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Formation of Fe4+based on the Fe-O bond lengths in perovskite Eu1-xSrxFeO3 10

Formation of Fe4+based on the Fe-O bond lengths in perovskit...

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10th Asian Physics Symposium 2023, APS 2023

作者： Rahman, Raihan Mohammad Akbar, Mochammad Yan Pandu Qori', Mohammad Dani Al Nugroho, Agustinus Agung Physics Graduate Program Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Jalan Ganesa 10 Bandung40132 Indonesia Physics of Magnetics and Photonics Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung Jalan Ganesa 10 Bandung40132 Indonesia

The physical properties of high oxidation state of transition metal oxide compounds have attracted many research interest for its potential applications. A systematic investigation of Fe4+ in Eu1-xSrxFeO3 with x = 0, 0.1, 0.2, 0.3, and 0.4 has been carried out in polycrystalline form obtained using sol-gel method. The single phase of Eu1-xSrxFeO3 is observed up to x = 0.3. The X-Ray powder pattern for low Sr content of x = 0.1, is best refined by using EuFeO3 crystal structure with Sr occupied the Eu-site. On the other hand, for higher Sr contents, two phases of EuFeO3 and Eu1/3Sr2/3FeO3 are required to obtained the best refinement. The result of the refinements shows that the volume and the average bond lengths of Fe-O decreases as increasing the Sr content. These results are consistent to support the existence of Fe4+ upon Sr doping in Eu1-xSrxFeO3. For the Sr content of x = 0.1, an anomalous change of the volume is observed. © Published under licence by IOP Publishing Ltd.

关键词： Iron compounds

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Disaster recovery plan implementation evaluation model at the corporation 7

Disaster recovery plan implementation evaluation model at th...

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7th Information Systems International Conference, ISICO 2023

作者： Sardjono, Wahyu Perdana, Widhilaga Gia Putra, Gustian Rama Information Systems Management Department BINUS Graduate Program - Master of Information Systems Management Bina Nusantara University Jakarta11480 Indonesia Post Graduate Program of Management Science State University of Jakarta Jl. R.Mangun Muka Raya No.11 Jakarta Timur Jakarta13220 Indonesia Computer Science Study Program Faculty of Mathematics & Natural Sciences Pakuan University Bogor Indonesia

The application of information technology in addition to making internal business processes more effective and efficient, is also to improve customer service. This role is important for companies to maintain the sustainability of information systems as a strategic tool for competitive advantage so system availability is absolutely essential. Research related to the Disaster Recovery Plan (DRP) needs to be carried out to see the readiness of a corporation to build a backup system in different places and locations. By using the method of factor analysis and regression analysis to form an evaluation model, it will obtain an overview of what factors must be considered and what the current conditions are. The results of the study show that there are Core Technical DRP, Organizational Preparation, and Costing factors which are the main variables in supporting DRP readiness. The conclusion from this study, through these three new factors a mathematical model can be built as a reference for improving DRP implementation in corporations. © 2023 The Authors. Published by Elsevier B.V.

关键词： Factor analysis

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Fast Cauchy Sum Algorithms for Polynomial Zeros and Matrix Eigenvalues 13th

Fast Cauchy Sum Algorithms for Polynomial Zeros and Matrix...

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13th International Symposium on Algorithms and Complexity, CIAC 2023

作者： Pan, Victor Y. Go, Soo Luan, Qi Zhao, Liang Department of Computer Science Lehman College of CUNY BronxNY United States Program in Computer Science The Graduate Center of the City University of New York New York United States Program in Mathematics The Graduate Center of the City University of New York New York United States

ISBN: (纸本)9783031304477

Given a black box oracle that evaluates a univariate polynomial p(x) of a degree d, we seek its zeros, aka the roots of the equation. At FOCS 2016, Louis and Vempala approximated within an absolutely largest zero of such a real-rooted polynomial at the cost of the evaluation of Newton’s ratio (formula presented) points x and then extended this algorithm to approximation of an absolutely largest eigenvalue of a symmetric matrix at a record Boolean cost. By applying distinct approach and techniques we obtain much more general results at the same computational cost. Our use of Cauchy integrals and randomization is non-trivial and pioneering in this field. Somewhat surprisingly, the Boolean complexity of the accelerated versions of our algorithms in [25, 26] reached below the known lower bounds on the Boolean complexity of polynomial root-finding. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Approximation algorithms

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