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Characteristics of plasma produced from tsunami impacted soil sample using a transversely excited atmospheric pressure-carbon dioxide (TEA-CO2) laser

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AIP Conference Proceedings 2023年第1期2480卷

作者： Rara Mitaphonna Muliadi Ramli Kurnia Lahna Nazli Ismail Kazuyoshi Kurihara Nasrullah Idris Doctoral Program of Mathematics and Applied Sciences Universitas Syiah Kuala 23111 Banda Aceh Indonesia Department of Chemistry Faculty of Mathematics and Natural Sciences Universitas Syiah Kuala Jl. Syech Abdurrauf No. 3 Darussalam 23111 Banda Aceh Aceh Indonesia Department of Physics Faculty of Mathematics and Natural Sciences Universitas Syiah Kuala Jl. Syech Abdurrauf No. 3 Darussalam 23111 Banda Aceh Aceh Indonesia Department of Physics Faculty of Education University of Fukui 3-9-1 Bunkyo Fukui 910-8507 Japan

In this work, plasma characteristics in terms of temperature and electron density of a plasma of the tsunami impacted soil sample induced by a transversely excited atmospheric carbon dioxide (TEA-CO2) LIBS was studied. Practically, the tsunami impacted soil samples was taken from at the worst affected area by the giant tsunami, Banda Aceh city, Aceh province, Indonesia. The generated plasma has been produced after TEA-CO2 pulses laser was targeted onto sample placed on a sample holder in air surrounding gas. The emission spectral lines emitted from the plasma region collected using system of an optical multichannel analyser (OMA) allowed atomic emission lines could be clearly identified. The temperature of plasma was estimateed through the method of Boltzmann plot, while the plasma electron density has been obtained by method of Saha-Boltzmann using spectral lines of calcium both atomic and ionic spectral lines. As results, the plasma temperature and electron density produced were T = 8691 K and 5,2 × 1015 cm−3, respectively. Generally, the plasma temperature and density electron obtained are fit to the Maxwell distribution criteria kT <50,000 and Mcwhriter’s criteria (Ne >1.6×1012 T½ (ΔE)3) for plasma laser in state of local thermal equilibrium LTE).

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Neural Canonical Transformation with Symplectic Flows

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Physical Review X 2020年第2期10卷 021020-021020页

作者： Shuo-Hui Li Chen-Xiao Dong Linfeng Zhang Lei Wang Institute of Physics Chinese Academy of Sciences Beijing 100190 China University of Chinese Academy of Sciences Beijing 100049 China Program in Applied and Computational Mathematics Princeton University Princeton New Jersey 08544 USA Songshan Lake Materials Laboratory Dongguan Guangdong 523808 China

Canonical transformation plays a fundamental role in simplifying and solving classical Hamiltonian systems. Intriguingly, it has a natural correspondence to normalizing flows with a symplectic constraint. Building on this key insight, we design a neural canonical transformation approach to automatically identify independent slow collective variables in general physical systems and natural datasets. We present an efficient implementation of symplectic neural coordinate transformations and two ways to train the model based either on the Hamiltonian function or phase-space samples. The learned model maps physical variables onto an independent representation where collective modes with different frequencies are separated, which can be useful for various downstream tasks such as compression, prediction, control, and sampling. We demonstrate the ability of this method first by analyzing toy problems and then by applying it to real-world problems, such as identifying and interpolating slow collective modes of the alanine dipeptide molecule and MNIST database images.

关键词： Collective dynamics Hamiltonian systems Artificial neural networks Molecular dynamics

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Exclusion Volumes of Convex Bodies in High Space Dimensions: Applications to Virial Coefficients and Continuum Percolation

arXiv

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arXiv 2022年

作者： Torquato, Salvatore Jiao, Yang Department of Chemistry Princeton University PrincetonNJ08544 United States Department of Physics Princeton University PrincetonNJ08544 United States Princeton Institute of Materials Princeton University PrincetonNJ08544 United States Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States Materials Science and Engineering Arizona State University TempeAZ85287 United States Department of Physics Arizona State University TempeAZ85287 United States

Using the concepts of mixed volumes and quermassintegrals of convex geometry, we derive an exact formula for the exclusion volume vex(K) for a general convex body K that applies in any space dimension. While our main interests concern the rotationally-averaged exclusion volume of a convex body with respect to another convex body, we also describe some results for the exclusion volumes for convex bodies with the same orientation. We show that the sphere minimizes the dimensionless exclusion volume vex(K)/v(K) among all convex bodies, whether randomly oriented or uniformly oriented, for any d, where v(K) is the volume of K. When the bodies have the same orientation, the simplex maximizes the dimensionless exclusion volume for any d with a large-d asymptotic scaling behavior of 22d/d3/2, which is to be contrasted with the corresponding scaling of 2d for the sphere. We present explicit formulas for quermassintegrals W0(K), . . ., Wd(K) for many different nonspherical convex bodies, including cubes, parallelepipeds, regular simplices, cross-polytopes, cylinders, spherocylinders, ellipsoids as well as lower-dimensional bodies, such as hyperplates and line segments. These results are utilized to determine the rotationally-averaged exclusion volume vex(K) for these convex-body shapes for dimensions 2 through 12. While the sphere is the shape possessing the minimal dimensionless exclusion volume, we show that, among the convex bodies considered that are sufficiently compact, the simplex possesses the maximal vex(K)/v(K) with a scaling behavior of 21.6618...d. Subsequently, we apply these results to determine the corresponding second virial coefficient B2(K) of the aforementioned hard hyperparticles. Our results are also applied to compute estimates of the continuum percolation threshold ηc derived previously by the authors for systems of identical overlapping convex bodies. We conjecture that overlapping spheres possess the maximal value of ηc among all identical nonzero-vol

关键词： Spheres

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Editorial

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Journal of Biological Dynamics 2019年第sup1期13卷 1-1页

作者： Cushing, Jim Elaydi, Saber Department of Mathematics and Interdisciplinary Program in Applied Mathematics University of Arizona Tucson AZ United States

The 6th International Conference on Mathematical Modelling and Analysis of Populations in Biology (ICMA-VI) was held at the University of Arizona, Tucson, Arizona USA on 20-22 October 2017. Plenary addresses were given by Henri Berestycki (Centre d'analyse et de mathématique sociales, Paris, France), Regis Ferriere (Ecology and Evolutionary Biology Department, University of Arizona, Tucson, Arizona, USA), Rosie Fisher (National Center for Atmospheric Research Climate & Global Dynamics, Boulder, Colorado, USA), and Mercedes Pascual (Department of Ecology and Evolution, University of Chicago, Chicago, Illinois, USA). The conference received support from the Department of mathematics, University of Arizona; the Department of Ecology and Evolutionary Biology, University of Arizona; the Interdisciplinary program in applied mathematics, University of Arizona; and the Simon A. Levin Mathematical, Computational and Modeling Sciences Center, Arizona State University. [Extracted from the article]

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Wave energy flux variability in the Caribbean sea

Research Square

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Research Square 2022年

作者： Orejarena-Rondón, Andrés F. Sayol, Juan-Manuel Hernández-Carrasco, Ismael Cáceres-Euse, Alejandro Restrepo, Juan C. Orfila, Alejandro Program of Marine and Coastal Geosciences INVEMAR Santa Marta Colombia Department of Applied Mathematics University of Alicante Sant Vicent del Raspeig Alicante03690 Spain Sistema de Observación Costero de les Illes Balears SOCIB Palma de Mallorca07007 Spain Esporles07190 Spain Mediterranean Institute of Oceanography MIO Université de Toulon Toulon83041 France Dpto. de Física y Geociencias Universidad del Norte Puerto Colombia081007 Colombia

Wave energy flux (WEF) is assessed in the Caribbean Sea from a 60-year (1958–2017) wave hindcast. We use a novel approach, based on neural networks, to identify coherent regions of similar WEF and their association with different climate patterns. This method allows for a better evaluation of the underlying dynamics behind seasonal and inter-annual WEF variability, including the effect induced by the latitudinal migration of the Intertropical Convergence Zone (ITCZ), and the influence of El Niño-Southern Oscillation events. Results show clear regional differences of the WEF variability likely due to both a clear regionalization of the WEF due to both the intensification and migration of the ITCZ. WEF exhibits a strong semiseasonal signal in areas of the continental shelf, with maximums in January and June, in agreement with the sea surface temperature and sea level pressure variability. At larger scales, WEF shows a significant correlation with the Oceanic Niño Index depicting positive values in the central and western basin and negative ones at the eastern side. © 2022, CC BY.

关键词： Surface temperature

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Orthogonal die random measures, primes, and applications

arXiv

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arXiv 2020年

作者： Bastian, Caleb Deen Rempala, Grzegorz A. Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States Massive Dynamics PrincetonNJ08542 United States Department of Mathematics Ohio State University ColumbusOH43210 United States Division of Biostatistics Ohio State University ColumbusOH43210 United States

We show that the sequence of thinned uniform random counting measures converges weakly to the Poisson random measure. We call such measures ‘orthogonal dice’ due to their natural connection with certain counting problems and link the sizes of orthogonal dice with the primes by constructing the largest known prime orthogonal die. We give many examples of possible use of the construct of orthogonal dice in various areas of applications including gambling, cosmology, random matrices, approximation theory and circuits. The gambling example reveals for instance that fair six-sided die numbered {1, 2, 3, 4, 5, 6} generate negative covariance in point representations of hands across players, in contrast to seven-sided dice numbered {1, 2, 3, 4, 5, 6, 7} that generate zero covariance and are orthogonal. The cosmology example suggests that a ‘supermassive’ orthogonal die underlies the galaxy point patterns of the Universe. The random matrix application reveals that the variance of the spectral gap of the Gaussian orthogonal ensemble exhibits non-monotone scaling with thinning for the Dirac (empirical) random measure, in contrast to the orthogonal dice where the spectral gap variance is monotone. Finally, the approximation application shows that the discrete Legendre polynomials converge to the Charlier polynomials in Lp for integers p ≥ 1 whereas the electronic circuit/shot noise application identifies electric current as the Ornstein-Uhlenbeck process driven by an orthogonal die random *** Codes 60G57, 60G55, 60F05 Copyright © 2020, The Authors. All rights reserved.

关键词： Poisson distribution

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Spectral Top-Down Recovery of Latent Tree Models

arXiv

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arXiv 2021年

作者： Aizenbud, Yariv Jaffe, Ariel Wang, Meng Hu, Amber Amsel, Noah Nadler, Boaz Chang, Joseph T. Kluger, Yuval Program in Applied Mathematics Yale University New HavenCT06511 United States Department of Computer Science Weizmann Institute of Science Rehovot76100 Israel Department of Statistics Yale University New HavenCT06520 United States Interdepartmental Program in Computational Biology and Bioinformatics Yale University New HavenCT06511 United States Department of Pathology Yale University New HavenCT06511 United States

Modeling the distribution of high dimensional data by a latent tree graphical model is a prevalent approach in multiple scientific domains. A common task is to infer the underlying tree structure, given only observations of its terminal nodes. Many algorithms for tree recovery are computationally intensive, which limits their applicability to trees of moderate size. For large trees, a common approach, termed divide-and-conquer, is to recover the tree structure in two steps. First, recover the structure separately of multiple, possibly random subsets of the terminal nodes. Second, merge the resulting subtrees to form a full tree. Here, we develop Spectral Top-Down Recovery (STDR), a deterministic divide-and-conquer approach to infer large latent tree models. Unlike previous methods, STDR partitions the terminal nodes in a non random way, based on the Fiedler vector of a suitable Laplacian matrix related to the observed nodes. We prove that under certain conditions, this partitioning is consistent with the tree structure. This, in turn, leads to a significantly simpler merging procedure of the small subtrees. We prove that STDR is statistically consistent and bound the number of samples required to accurately recover the tree with high probability. Using simulated data from several common tree models in phylogenetics, we demonstrate that STDR has a significant advantage in terms of runtime, with improved or similar accuracy. Copyright © 2021, The Authors. All rights reserved.

关键词： Recovery

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Thermal Correction of Eu 3+ doped Na 2 O-Al 2 O 3 -P 2 O 5 Glasses System

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Materials Today: Proceedings 2021年 43卷 2490-2497页

作者： N. Chanthima J. Kaewkhao Y. Tariwong N. Kiwsakunkran N. Sangwaranatee N.W. Sangwaranatee Physics Program Faculty of Science and Technology Nakhon Pathom Rajabhat University Nakhon Pathom 73000 Thailand Center of Excellence in Glass Technology and Materials Science (CEGM) Nakhon Pathom Rajabhat University Nakhon Pathom 73000 Thailand Applied Physics Faculty of Science and Technology Suan Sunandha Rajabhat University Bangkok 10300 Thailand Informatics Mathematics Faculty of Science and Technology Suan Sunandha Rajabhat University Bangkok 10300 Thailand

Optical absorption, excitation, emission spectra and lasing potential of sodium aluminium phosphate (Na 2 O-Al 2 O 3 -P 2 O 5 ) glasses doped with Eu 3+ ions were studied and discussed. These glasses were synthesized by melt-quenching technique at 1200 °C. It was found that the emission spectra of glass samples exhibited an intense red (612 nm) emission band upon excitation with 394 nm. Judd-Ofelt (JO) intensity parameters (Ω λ=2,4,6 ), radiative transition probabilities (A R ), peak stimulated emission cross-sections ( σ (λ p )) and branching ratio ( β ) were calculated and compared between without and with thermal corrections. The evaluated JO values indicated that, this glass perform high potential for using as red laser medium application

关键词： Europium Judd-Ofelt analysis Phosphate glass Thermal corrections

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Stealthy and hyperuniform isotropic photonic bandgap structure in 3D

arXiv

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arXiv 2024年

作者： Siedentop, Lukas Lui, Gianluc Maret, Georg Chaikin, Paul M. Steinhardt, Paul J. Torquato, Salvatore Keim, Peter Florescu, Marian Department of Physics University of Konstanz Konstanz78457 Germany Advanced Technology Institute Department of Physics University of Surrey Surrey GuildfordGU2 7XH United Kingdom Department of Physics New York University New YorkNY20012 United States Department of Physics Princeton University PrincetonNJ08544 United States Department of Chemistry Princeton University PrincetonNJ08544 United States Princeton Materials Institute Princeton University PrincetonNJ08544 United States Program in Applied and Computational Mathematics Princeton University PrincetonNJ08544 United States Max-Planck-Institute for Dynamics and Self-Organization Göttingen37077 Germany Institute for the Dynamics of Complex Systems University of Göttingen Göttingen37077 Germany

In photonic crystals the propagation of light is governed by their photonic band structure, an ensemble of propagating states grouped into bands, separated by photonic band gaps. Due to discrete symmetries in spatially strictly periodic dielectric structures their photonic band structure is intrinsically anisotropic. However, for many applications, such as manufacturing artificial structural color materials or developing photonic computing devices, but also for the fundamental understanding of light-matter interactions, it is of major interest to seek materials with long range non-periodic dielectric structures which allow the formation of isotropic photonic band gaps. Here, we report the first ever 3D isotropic photonic band gap for an optimized disordered stealthy hyperuniform structure for microwaves. The transmission spectra are directly compared to a diamond pattern and an amorphous structure with similar node density. The band structure is measured experimentally for all three microwave structures, manufactured by 3D-Laser-printing for meta-materials with refractive index up to n = 2.1. Results agree well with finite-difference-time-domain numerical investigations and a priori calculations of the band-gap for the hyperuniform structure: the diamond structure shows gaps but being anisotropic as expected, the stealthy hyperuniform pattern shows an isotropic gap of very similar magnitude, while the amorphous structure does not show a gap at all. The centimeter scaled microwave structures may serve as prototypes for micrometer scaled structures with bandgaps in the technologically very interesting region of infrared (IR). Copyright © 2024, The Authors. All rights reserved.

关键词： Anisotropy

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Web-Based Comprehensive Assessment for Postpartum Care using Rule-Based Algorithm 1

Web-Based Comprehensive Assessment for Postpartum Care using...

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1st International Conference on Computer, Science, Engineering and Technology, ICComSET 2018

作者： Mujahidah, S. Suryono, S. Widyawati, M.N. Department of Midwifery STIKES Karya Husada Semarang Indonesia Department of Physics Faculty of Mathematics and Natural Sciences Universitas Diponegoro Indonesia Postgraduate Program in Applied Midwifery Science Poltekkes Kemenkes Semarang Indonesia

Administration of postpartum care has been performed in line with health care standards. Unfortunately the health service medical record data is still *** results in delays in establishing a diagnosis and providing therapy which results in a worsening of the postpartum mother's *** paper proposes a web-based information system that may become one solution in solving the remaining issues in postpartum care. The system developed here is expected to improve health care quality with better data completion of postpartum mothers and access to them. The system developed here is web-based, in that it applies the rule-based artificial intelligence system. Input of the system are results of physical examination performed by medical professionals. Then processed using the rule-based algorithm to produce diagnosis and proper recommendation. This research is quasi-experimental using posttest only with control group. There were 40 were categorized into intervention group (n=20) who used the information system and control group (n=20) who used the present system endorsed by the government.. The rule-based algorithm in the information system uses validation from experts. Results show that the information system developed here is capable of solving the issue of incomprehensive data, as well as effectiveness in providing postpartum care. © 2019 IOP Publishing Ltd. All rights reserved.

关键词： Diagnosis

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