Article
Engineering, Electrical & Electronic
Mark S. Haynes, Ines Fenni
Summary: This article derives expressions for the ideal free-space backprojected image of an object with known transition matrix (T-matrix) for scalar and vector electromagnetic waves in bistatic and monostatic geometries. Discrete backprojection sums are extended to continuous integrals over source/receiver spheres. The formulation is validated numerically using the aggregate T-matrix solution for a collection of acoustic and dielectric spheres. Applications include assessment and validation of free-space focusing and T-matrix scattering solutions.
IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION
(2023)
Article
Mathematics, Interdisciplinary Applications
Xu Yang, Liang Li, Hongzhe Dai, Mingming Jia
Summary: The fractal dimension of cement paste was used to describe the geometric form of concrete at the meso-level. It was found that the compressive behavior of concrete varied with different fractal dimensions, while the tensile behavior remained relatively unchanged.
FRACTALS-COMPLEX GEOMETRY PATTERNS AND SCALING IN NATURE AND SOCIETY
(2021)
Article
Materials Science, Multidisciplinary
Mohammad Partohaghighi, Zahrasadat Mirtalebi, Ali Akgul, Muhammad Bilal Riaz
Summary: This article introduces a new type of fractional Klein-Gordon problem and solves it numerically. Using operational matrix technique and basic functions, the approximate solutions of the problem are obtained, and the numerical results and errors are shown through graphs.
RESULTS IN PHYSICS
(2022)
Article
Mathematics, Interdisciplinary Applications
Lei Shi, Malik Zaka Ullah, Hemant Kumar Nashine, Monairah Alansari, Stanford Shateyi
Summary: This article discusses the importance of computing the sign function of a matrix in mathematical applications and presents a new iterative algorithm for efficiently calculating the sign of an invertible matrix. Numerical experiments confirm the effectiveness and efficiency of the proposed algorithm.
FRACTAL AND FRACTIONAL
(2023)
Article
Computer Science, Interdisciplinary Applications
M. H. Heydari, A. Atangana, Z. Avazzadeh
Summary: This paper introduces a new version of the nonlinear Ginzburg-Landau equation derived from fractal-fractional derivatives and proposes a computational scheme for numerical solutions. The method is based on shifted Chebyshev polynomials and collocation scheme, which separates the unknown solution into real and imaginary parts and expands them with undetermined coefficients for accurate results. The proposed approach is examined through numerical examples, confirming its accuracy in providing satisfactory results.
ENGINEERING WITH COMPUTERS
(2021)
Article
Engineering, Multidisciplinary
Mohammad Partohaghighi, Marzieh Mortezaee, Ali Akguel, Ahmed M. Hassan, Necibullah Sakar
Summary: The study introduces a new variant of the fractal-fractional diffusion equation using the fractal-fractional operator. It proposes a novel operational matrix technique to solve the equation, transforming it into an algebraic system. The study presents graphical and tabular representations of exact and approximated solutions, along with corresponding errors, and conducts comparative analysis of solutions at specific time points.
ALEXANDRIA ENGINEERING JOURNAL
(2024)
Article
Mechanics
Jianhong Fu, Sheng Chen, Xiaochen Zhou
Summary: Particle-resolved direct numerical simulation (PR-DNS) is used to analyze the influence of heterogeneous particle distribution on gas-solid heat transfer calculation. The results show that the heterogeneous CFD-DEM grid leads to an overestimation of heat transfer rate by Gunn's correlation, and even reducing the grid size cannot eliminate the error. Modifications to Gunn's correlation are proposed to reflect the influence of particle heterogeneity on heat transfer rate.
Article
Construction & Building Technology
Mohit Pundir, Guillaume Anciaux
Summary: This paper investigates the role of roughness on shear resistance in cracked concrete surfaces. By numerically matching experimental results, a reliable and physically based method for predicting shear transfer phenomena in concrete is proposed. The study provides an empirical power-law predicting shear resistance in concrete, taking into account micro-scale roughness and aggregate distribution.
JOURNAL OF ADVANCED CONCRETE TECHNOLOGY
(2021)
Article
Biochemistry & Molecular Biology
Jaeda M. Mendoza, Kenzie Chen, Sequoyah Walters, Emily Shipley, Kevin B. Aptowicz, Stephen Holler
Summary: In this study, computationally generated light scattering patterns were used to classify aerosol particles through morphological descriptors. The results showed improved accuracy compared to previous efforts, demonstrating the utility of the proposed descriptors.
Article
Automation & Control Systems
Parisa Rahimkhani, Yadollah Ordokhani, Salameh Sedaghat
Summary: In this study, a method based on Muntz-Legendre polynomials (M-LPs) is proposed for solving fractal-fractional 2D optimal control problems. The method involves obtaining operational matrices of fractal-fractional-order derivative, integer-order integration, and derivative of the M-LPs. By applying the M-LPs, operational matrices, and Gauss-Legendre integration, the problem is transformed into a system of algebraic equations which is solved using Newton's iterative method. An error bound is also introduced for the method, and two examples are provided to demonstrate its applicability and validity.
OPTIMAL CONTROL APPLICATIONS & METHODS
(2023)
Article
Mathematics, Applied
Arezou Rezazadeh, Zakieh Avazzadeh
Summary: This paper presents a numerical approach for solving two-dimensional fractal-fractional parabolic partial differential equations, utilizing fractal-fractional derivative definition and operational matrix simplification, with computational efficiency demonstrated through numerical results.
INTERNATIONAL JOURNAL OF COMPUTER MATHEMATICS
(2022)
Article
Spectroscopy
Nikolai G. Khlebtsov, Eric C. Le Ru
Summary: Analytical expressions for the surface- and orientation-averaged surface enhanced Raman scattering factor for small plasmonic spheroids are derived in this study, showing significant differences from previous approximations. The introduction of an improved electrostatic approximation provides more accurate results and better agreement with T-matrix calculations. The overestimation of SERS EF for spheroids due to higher curvature at the tips is discussed, along with possible generalizations to other axially symmetrical particles.
JOURNAL OF RAMAN SPECTROSCOPY
(2021)
Article
Optics
Carynelisa Haspel, Idan Cohen
Summary: We propose a method for calculating multiple scattering of electromagnetic radiation by a collection of sparsely spaced spherical scatterers. The method is based on first principles and is conceptually similar to the superposition T-matrix method. However, our implementation, called the SSSS scheme, is simpler and more suitable for numerical calculations with sparse spacing. It has important applications in studying the effects of spatial configurations of drops within water clouds and in other research fields where the exact configuration of scatterers is crucial.
Article
Mathematics, Applied
Mohammad Hossein Heydari, Abdon Atangana, Zakieh Avazzadeh
Summary: This article introduces a new method for solving a new category of nonlinear optimal control problems explained by fractal-fractional dynamical systems. The method is based on shifted Legendre polynomials, which approximate state and control variables. The accuracy of the method is verified through numerical examples.
MATHEMATICAL METHODS IN THE APPLIED SCIENCES
(2021)
Article
Optics
Ivan Sekulic, Jian Wei You, Nicolae C. Panoiu
Summary: This article presents a T-matrix method for numerical computation of second-harmonic generation from clusters of arbitrarily distributed spherical particles made of centrosymmetric optical materials. By taking into account both local surface and nonlocal bulk polarization sources when computing the SH fields, our method accurately describes the generation of SH in arbitrary clusters of spherical particles. The numerical method can efficiently analyze clusters of spherical particles made of various optical materials.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2021)
Article
Optics
Jianbao Zhao, Brant E. Billinghurst, Paul L. Raston
Summary: The far-infrared spectrum of room temperature formic acid labeled with 13C has been recorded and analyzed, leading to the determination of accurate line positions and predictions relevant to Earth's atmosphere and interstellar sources.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2024)
Article
Optics
Semen Vasilchenko, Alexander Solodov, Oleg Egorov, Vladimir Tyuterev
Summary: Ozone plays a crucial role in atmospheric chemistry and radiative processes, and it may serve as a potential biosignature species in exoplanetary observations. This study utilized a continuous-wave cavity-ring-down spectrometer to accurately measure the absorption cross-sections of ozone in the near-infrared range. The results provide more precise data and have potential applications in atmospheric research.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2024)
Article
Optics
Baorui Huang, Bo Peng, Qifeng Ren, Sheng Liao
Summary: This study utilizes the polarization bidirectional reflectance distribution function (p-BRDF) model derived from the microfacet theory to analyze the spectral p-BRDF of a brass surface. The results show that factors such as polarization state, wavelength, surface roughness, and permittivity have a significant impact on the distribution of BRDF on the object surface.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2024)
Article
Optics
Qingwei Duan, Jiajie Wang, Qiwei Li, Xiang'e Han, Kuan Fang Ren
Summary: This paper introduces the applications of the generalized Lorenz-Mie theory (GLMT) and the vectorial complex ray model (VCRM) in the interaction between beams and particles. By comparing the experimental results, it is found that VCRM performs well in Gaussian beam scattering problems, providing a new method for studying the scattering of shaped beams by large particles/objects of any shape.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2024)
Article
Optics
Yuefan Du, Xiaoping Li, Lei Shi, Fangyan Li, Shurong Yuan
Summary: This study proposes a physics-constrained model that utilizes the distribution characteristics of gas spectral parameters to predict spectral parameters for unknown wavelengths. Experimental results show that the model improves prediction accuracy and increases the data volume of gas spectral parameters by 4-5 times.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2024)
Article
Optics
Laurentius Windholz, Imran Siddiqui, Shamim Khan, Syed Tanweer Iqbal
Summary: In this study, we report the discovery of two energy levels of the Pr atom that exhibit strong J-mixing, as well as the observed hyperfine structure patterns. The composition of wave functions, in addition to J-values, plays a crucial role in determining the appearance of these patterns.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2024)
Article
Optics
Matthias Germann, Adrian Hjalten, Jonathan Tennyson, Sergei N. Yurchenko, Iouli E. Gordon, Christian Pett, Isak Silander, Karol Krzempek, Arkadiusz Hudzikowski, Aleksander Gluszek, Grzegorz Sobon, Aleksandra Foltynowicz
Summary: In this study, optical frequency comb Fourier transform spectroscopy was used to record the spectroscopic data of formaldehyde in a specific frequency range. The line positions and intensities of rovibrational transitions were obtained through line-by-line fitting. By incorporating these accurate line positions into the analysis, more energy levels and rovibrational transitions were predicted with reduced uncertainties in the H2CO spectrum.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2024)
Article
Optics
Leonardo A. Ambrosio, Jhonas O. de Sarro, Gerard Gouesbet
Summary: This study derives a polychromatic version of the generalized Lorenz-Mie theory stricto sensu (GLMT) by expanding arbitrary time-dependent fields into partial waves using Bromwich scalar potentials. The new formalism introduces field shape spectra (FSSs) which are intrinsically frequency-dependent, modifying and redefining the physical quantities expressed in the monochromatic GLMT.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2024)
Article
Optics
Patrick C. Chaumet
Summary: The paper proposes two new methods (IDR(s) and GPBiCGstab(L)) for computing the electromagnetic diffraction of objects larger than the wavelength. It is found that IDR(s) can reduce computation time but may not converge in some cases, while GPBiCGstab(L) always converges and also reduces computation time compared to QMR, GPBiCG, and BiCGstab.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2024)
Article
Optics
Antigoni Kleanthous, Anthony J. Baran, Timo Betcke, David P. Hewett, Christopher D. Westbrook
Summary: To improve weather and climate models, it is important to accurately calculate the single-scattering properties of randomly oriented complex atmospheric ice crystals. This study applies Boundary Element Method (BEM) to calculate these properties in the microwave and sub-millimeter region of the electromagnetic spectrum for all-sky data assimilation. The results show that BEM can accurately compute the scattering properties of complex ice aggregates, which is crucial for weather and climate models.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2024)
Article
Optics
Ben Niu, Yanting Li, Gang Xiong, Jihui Chen, Zhimin Hu, Yunqing Fu, Yaming Zou, Chongyang Chen, Ke Yao
Summary: This study presents both experimental and theoretical analysis of the 4d 2D5/2 -> 2D3/2 magnetic dipole transition in Rb-like ions. The correlation between the theoretical and experimental findings is observed, and it is illustrated that the contribution of the core-valence correlation is pivotal for the fine structure splittings.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2024)
Article
Optics
James A. Lock, Gunther P. Konnen, Philip Laven
Summary: Researchers have derived an analytical generalization of Airy theory that provides a more accurate approximation for the primary rainbow, but still has limitations for the second-order rainbow and beyond.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2024)
Article
Optics
Shixiong Wu, Xuebang Gao, Xuqiang Dou, Li Xie
Summary: In this paper, an indoor experimental study was conducted to investigate the optical attenuation caused by sand/dust storms at different relative humidity levels. It was found that the hygroscopic growth of sand/dust particles has a significant effect on optical attenuation when the relative humidity is above 60%. Based on the double-parameter Kasten model, a proposed optical attenuation model takes into account visibility, particle size, relative humidity, and optical wavelength. Numerical calculations considering the hygroscopicity effect were also performed, and the results were in agreement with the experimental data.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2024)
Article
Optics
Zhimin Yang, Jaeman Song, Bong Jae Lee
Summary: In this study, we analyze TPX cells operating in the self-sustaining circuit and examine the effects of different bandgaps on their performance. The results show that the bandgap energy of the LED must exceed that of the PV cell for the TPX cell to function in a self-sustaining parallel circuit. Additionally, a narrower bandgap energy for the PV cell and a wider bandgap energy for the LED can improve the performance of the TPX cell in the self-sustaining circuit.
JOURNAL OF QUANTITATIVE SPECTROSCOPY & RADIATIVE TRANSFER
(2024)