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Автор: Grafiati

Опубліковано: 23 лютого 2024

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1

Fortunato, Daniel, and Alex Townsend. "Fast Poisson solvers for spectral methods." IMA Journal of Numerical Analysis 40, no. 3 (November 29, 2019): 1994–2018. http://dx.doi.org/10.1093/imanum/drz034.

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Abstract Poisson’s equation is the canonical elliptic partial differential equation. While there exist fast Poisson solvers for finite difference (FD) and finite element methods, fast Poisson solvers for spectral methods have remained elusive. Here we derive spectral methods for solving Poisson’s equation on a square, cylinder, solid sphere and cube that have optimal complexity (up to polylogarithmic terms) in terms of the degrees of freedom used to represent the solution. Whereas FFT-based fast Poisson solvers exploit structured eigenvectors of FD matrices, our solver exploits a separated spectra property that holds for our carefully designed spectral discretizations. Without parallelization we can solve Poisson’s equation on a square with 100 million degrees of freedom in under 2 min on a standard laptop.

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2

Hosseinzadegan, Samar, Andreas Fhager, Mikael Persson, and Paul Meaney. "A Discrete Dipole Approximation Solver Based on the COCG-FFT Algorithm and Its Application to Microwave Breast Imaging." International Journal of Antennas and Propagation 2019 (July 17, 2019): 1–12. http://dx.doi.org/10.1155/2019/9014969.

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We introduce the discrete dipole approximation (DDA) for efficiently calculating the two-dimensional electric field distribution for our microwave tomographic breast imaging system. For iterative inverse problems such as microwave tomography, the forward field computation is the time limiting step. In this paper, the two-dimensional algorithm is derived and formulated such that the iterative conjugate orthogonal conjugate gradient (COCG) method can be used for efficiently solving the forward problem. We have also optimized the matrix-vector multiplication step by formulating the problem such that the nondiagonal portion of the matrix used to compute the dipole moments is block-Toeplitz. The computation costs for multiplying the block matrices times a vector can be dramatically accelerated by expanding each Toeplitz matrix to a circulant matrix for which the convolution theorem is applied for fast computation utilizing the fast Fourier transform (FFT). The results demonstrate that this formulation is accurate and efficient. In this work, the computation times for the direct solvers, the iterative solver (COCG), and the iterative solver using the fast Fourier transform (COCG-FFT) are compared with the best performance achieved using the iterative solver (COCG-FFT) in C++. Utilizing this formulation provides a computationally efficient building block for developing a low cost and fast breast imaging system to serve under-resourced populations.

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3

Morin, Léo, Renald Brenner, Katell Derrien, and Khaoula Dorhmi. "Periodic smoothing splines for FFT-based solvers." Computer Methods in Applied Mechanics and Engineering 373 (January 2021): 113549. http://dx.doi.org/10.1016/j.cma.2020.113549.

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4

Fang, Jiannong. "A Fast Hybrid Pressure-Correction Algorithm for Simulating Incompressible Flows by Projection Methods." Algorithms 16, no. 6 (June 2, 2023): 287. http://dx.doi.org/10.3390/a16060287.

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Анотація:

To enforce the conservation of mass principle, a pressure Poisson equation arises in the numerical solution of incompressible fluid flow using the pressure-based segregated algorithms such as projection methods. For unsteady flows, the pressure Poisson equation is solved at each time step usually in physical space using iterative solvers, and the resulting pressure gradient is then applied to make the velocity field divergence-free. It is generally accepted that this pressure-correction stage is the most time-consuming part of the flow solver and any meaningful acceleration would contribute significantly to the overall computational efficiency. The objective of the present work was to develop a fast hybrid pressure-correction algorithm for numerical simulation of incompressible flows around obstacles in the context of projection methods. The key idea is to adopt different numerical methods/discretisations in the sub-steps of projection methods. Here, a classical second-order time-marching projection method, which consists of two sub-steps, was chosen for the purposes of demonstration. In the first sub-step, the momentum equations were discretised on unstructured grids and solved by conventional numerical methods, here a meshless method. In the second sub-step (pressure-correction), the proposed algorithm adopts a double-discretisation system and combines the weighted least-squares approximation with the essence of immersed boundary methods. Such a design allowed us to develop an FFT-based solver to speed up the solution of the pressure Poisson equation for flow cases with obstacles, while keeping the implementation of the boundary conditions for the momentum equations as easy as conventional numerical methods do with unstructured grids. The numerical experiments of five test cases were performed to verify and validate the proposed hybrid algorithm and evaluate its computational performance. The results showed that the new FFT-based hybrid algorithm works and is robust, and it was significantly faster than the multigrid-based reference method. The hybrid algorithm opens an avenue for the development of next-generation high-performance parallel computational fluid dynamics solvers for incompressible flows.

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5

de Geus, T. W. J., J. Vondřejc, J. Zeman, R. H. J. Peerlings, and M. G. D. Geers. "Finite strain FFT-based non-linear solvers made simple." Computer Methods in Applied Mechanics and Engineering 318 (May 2017): 412–30. http://dx.doi.org/10.1016/j.cma.2016.12.032.

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6

LAURITSCH, G., and P. G. REINHARD. "AN FFT SOLVER FOR THE COULOMB PROBLEM." International Journal of Modern Physics C 05, no. 01 (February 1994): 65–75. http://dx.doi.org/10.1142/s0129183194000064.

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Анотація:

A solution of the Coulomb problem in Fourier representation is given. The problems with the long-range parts of the Coulomb potential are circumvented by a separate handling of them. This allows the Fourier representation to develop its typical efficiency and robusteness.

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7

Sharma, L., R. H. J. Peerlings, M. G. D. Geers, and F. Roters. "Integral nonlocal approach to model interface decohesion in FFT solvers." Engineering Fracture Mechanics 243 (February 2021): 107516. http://dx.doi.org/10.1016/j.engfracmech.2020.107516.

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8

Heymann, Dieter, and Franco Cataldo. "UNSTABLE PRODUCTS FROM THE OZONATION OF C60IN SOLVENTS." Fullerene Science and Technology 9, no. 1 (February 26, 2001): 71–76. http://dx.doi.org/10.1081/fst-100000166.

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9

Murthy, C. N., and K. E. Geckeler. "SOLUBILITY CORRELATION OF [60]FULLERENE IN DIFFERENT SOLVENTS." Fullerene Science and Technology 9, no. 4 (August 31, 2001): 477–86. http://dx.doi.org/10.1081/fst-100107150.

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10

Nath, S., H. Pal, A. V. Sapre, V. P. Bubnov, Y. I. Estrin, T. A. Parnyuk, and V. K. Koltover. "Aggregation of Endometallofullerene Y@C82 in Polar Solvents." Fullerenes, Nanotubes and Carbon Nanostructures 12, no. 1-2 (January 2, 2005): 53–57. http://dx.doi.org/10.1081/fst-120027133.

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11

Starn, Jos. "A Simple Fluid Solver Based on the FFT." Journal of Graphics Tools 6, no. 2 (January 2001): 43–52. http://dx.doi.org/10.1080/10867651.2001.10487540.

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12

Zhang, Huai Qing, Ran Liu, and Hao Xiong. "Harmonic and Inter-Harmonic Detection Based on FFT and Nonlinear Optimization." Applied Mechanics and Materials 220-223 (November 2012): 2235–39. http://dx.doi.org/10.4028/www.scientific.net/amm.220-223.2235.

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Анотація:

In order to analyze harmonic and inter-harmonic parameters more accurately, a new detecting method that combined the nonlinear least squares and fast Fourier transform(FFT) was proposed. The FFT was used to produce a rough estimated value of harmonic parameters and then the signal model was set. Finally, the parameters can be estimated more accurately by the use of optimization algorithm which based on damped nonlinear-least squares method. The combined method solves the problem of inaccurate estimate by FFT and solves the problem of how to set the signal model and to choose initial value. The simulation results show that the combined method is effective and far more accuracy than interpolated Hanning window method.

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13

Jovanovic, T., Dj Koruga, B. Jovancicevic, and J. Simic‐Krstic. "Modifications of Fullerenes Extractions and Chromatographies with Different Solvents." Fullerenes, Nanotubes and Carbon Nanostructures 11, no. 4 (December 2003): 383–94. http://dx.doi.org/10.1081/fst-120025857.

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14

Khoromskaia, Venera, and Boris N. Khoromskij. "Block Circulant and Toeplitz Structures in the Linearized Hartree–Fock Equation on Finite Lattices: Tensor Approach." Computational Methods in Applied Mathematics 17, no. 3 (July 1, 2017): 431–55. http://dx.doi.org/10.1515/cmam-2017-0004.

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Анотація:

AbstractThis paper introduces and analyzes the new grid-based tensor approach to approximate solutions of the elliptic eigenvalue problem for the 3D lattice-structured systems. We consider the linearized Hartree–Fock equation over a spatial{L_{1}\times L_{2}\times L_{3}}lattice for both periodic and non-periodic problem setting, discretized in the localized Gaussian-type orbitals basis. In the periodic case, the Galerkin system matrix obeys a three-level block-circulant structure that allows the FFT-based diagonalization, while for the finite extended systems in a box (Dirichlet boundary conditions) we arrive at the perturbed block-Toeplitz representation providing fast matrix-vector multiplication and low storage size. The proposed grid-based tensor techniques manifest the twofold benefits: (a) the entries of the Fock matrix are computed by 1D operations using low-rank tensors represented on a 3D grid, (b) in the periodic case the low-rank tensor structure in the diagonal blocks of the Fock matrix in the Fourier space reduces the conventional 3D FFT to the product of 1D FFTs. Lattice type systems in a box with Dirichlet boundary conditions are treated numerically by our previous tensor solver for single molecules, which makes possible calculations on rather large{L_{1}\times L_{2}\times L_{3}}lattices due to reduced numerical cost for 3D problems. The numerical simulations for both box-type and periodic{L\times 1\times 1}lattice chain in a 3D rectangular “tube” withLup to several hundred confirm the theoretical complexity bounds for the block-structured eigenvalue solvers in the limit of largeL.

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15

Polimeridis, A. G., J. F. Villena, L. Daniel, and J. K. White. "Stable FFT-JVIE solvers for fast analysis of highly inhomogeneous dielectric objects." Journal of Computational Physics 269 (July 2014): 280–96. http://dx.doi.org/10.1016/j.jcp.2014.03.026.

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16

Huang, Yin-Liang, Jian-Guo Liu, and Wei-Cheng Wang. "An FFT Based Fast Poisson Solver on Spherical Shells." Communications in Computational Physics 9, no. 3 (March 2011): 649–67. http://dx.doi.org/10.4208/cicp.060509.080609s.

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AbstractWe present a fast Poisson solver on spherical shells. With a special change of variable, the radial part of the Laplacian transforms to a constant coefficient differential operator. As a result, the Fast Fourier Transform can be applied to solve the Poisson equation with operations. Numerical examples have confirmed the accuracy and robustness of the new scheme.

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17

Taboada, J. M., L. Landesa, F. Obelleiro, J. L. Rodriguez, J. M. Bertolo, M. G. Araujo, J. C. Mourino, and A. Gomez. "High Scalability FMM-FFT Electromagnetic Solver for Supercomputer Systems." IEEE Antennas and Propagation Magazine 51, no. 6 (December 2009): 20–28. http://dx.doi.org/10.1109/map.2009.5433091.

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18

Биглова, Ю. Н., Р. Б. Салихов, И. Н. Сафаргалин, Т. Р. Салихов та А. Г. Мустафин. "Поли-2(1-циклопент-2-ен-1-ил)анилин: синтез и исследование электрофизических и физико-химических свойств". Физика твердого тела 61, № 11 (2019): 2249. http://dx.doi.org/10.21883/ftt.2019.11.48437.432.

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Анотація:

The synthesis of a new electron-donating conductive polymer –2- (1-cyclopent-2-en-1-yl) aniline was carried out and the polymerization process was optimized by the mole ratio of monomer: oxidizer and reaction time. The extraction and solubility of functionalized polyaniline in typical organic solvents differing in polarity are evaluated. For the obtained high-molecular compound, the dependence of the electrical conductivity on temperature was studied, the carrier mobility was calculated, and a thermogravimetric analysis was performed.

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19

Ladbrooke, P. H., A. J. Hill, and J. P. Bridge. "Fast FET and HEMT solvers for microwave CAD." International Journal of Microwave and Millimeter-Wave Computer-Aided Engineering 3, no. 1 (January 1993): 37–60. http://dx.doi.org/10.1002/mmce.4570030107.

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20

Yamauchi, Soron, Shunsuke Aoki, Masayuki Mizuno, and Takashiro Akitsu. "Risk of Fire and Health Hazards Due to Organic Solvents in Chemical Laboratories." Fire Science and Technology 40, no. 1 (2021): 15–24. http://dx.doi.org/10.3210/fst.40.15.

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21

Cataldo, Franco. "Soot and other Products Formation from the Submerged Carbon Arc in Halogenated Solvents." Fullerenes, Nanotubes, and Carbon Nanostructures 13, no. 3 (May 1, 2005): 239–57. http://dx.doi.org/10.1081/fst-200056248.

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22

Scrob, Stancuta, Sevastita Muste, Crina Muresan, Anca Farcas, Sonia Socaci, and Romina Vlaic. "Evaluation of Extraction Methods for the Analysis of Carotenoids for Different Vegetable Matrix." Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Food Science and Technology 70, no. 2 (November 13, 2013): 145. http://dx.doi.org/10.15835/buasvmcn-fst:9500.

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Анотація:

In this study, different solvents were used to achieve the maximum extractibility of total carotenoids. The extracted total carotenoids were estimated using UV- visible spectrophotometer. Carotenoids from vegetable matrix can be used as a food colorant, food additive, cosmetics, antioxidants and nutraceuticals.

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23

Jing Wu, Joseph JaJa, and Elias Balaras. "An Optimized FFT-Based Direct Poisson Solver on CUDA GPUs." IEEE Transactions on Parallel and Distributed Systems 25, no. 3 (March 2014): 550–59. http://dx.doi.org/10.1109/tpds.2013.53.

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24

Ladecký, Martin, Richard J. Leute, Ali Falsafi, Ivana Pultarová, Lars Pastewka, Till Junge, and Jan Zeman. "An optimal preconditioned FFT-accelerated finite element solver for homogenization." Applied Mathematics and Computation 446 (June 2023): 127835. http://dx.doi.org/10.1016/j.amc.2023.127835.

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25

Budiardja, Reuben D., and Christian Y. Cardall. "Parallel FFT-based Poisson solver for isolated three-dimensional systems." Computer Physics Communications 182, no. 10 (October 2011): 2265–75. http://dx.doi.org/10.1016/j.cpc.2011.05.014.

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26

STĂNILĂ, Andreea, Zoriţa DIACONEASA, Rodica SIMA, Sorin STĂNILĂ, and Nicușor SIMA. "Effects of Extraction Solvents on the Quantification of Free Amino Acids in Lyophilised Brewer’s Yeast." Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca. Food Science and Technology 75, no. 1 (May 17, 2018): 53. http://dx.doi.org/10.15835/buasvmcn-fst:2017.0037.

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Анотація:

The aim of this work was to test some solvents in order to improve the free amino acids extraction from lyophilised brewer’s yeast. The brewer’ yeast was treated with four types of extraction solvents: Solvent I – acetonitrile 25%/HCl 0.01M (ACN); Solvent II – ethanol 80%; solvent III – HCl 0.05M/deionized water (1/1 volume); Solvent IV – HCl 0.05M/ethanol 80% (1/1 volume). The supernatants were analysed by HPLC-DAD-ESI-MS method. Acetonitrile provided the less quantities and number of amino acids extracted due to its weaker polarity. Solvent II and IV (ethanol, respectively acidified ethanol), which have an increased polarity, extracted 15 amino acids due to the addition of HCl in solvent IV. Solvent III (acidified water) proved to be the best extraction solvent for the amino acids from brewer’s yeast providing the separation of 17 compounds: GLN, ASN, SER, GLY, ALA, ORN, PRO, HIS, LYS, GLU, TRP, LEU, PHE, ILE, AAA, HPHE, TYR.

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27

Masteli?, Josip. "The essential oil co-distillation by superheated vapour of organic solvents from aromatic plants." Flavour and Fragrance Journal 16, no. 5 (2001): 370–73. http://dx.doi.org/10.1002/ffj.1015.

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28

Cu, Jian-Qin, F. Perineau, M. Deltnas, and A. Gaset. "Comparison of the chemical composition of carrot seed essential oil extracted by different solvents." Flavour and Fragrance Journal 4, no. 4 (December 1989): 225–31. http://dx.doi.org/10.1002/ffj.2730040414.

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29

Еуров, Д. А., E. Ю. Стовпяга, Д. А. Курдюков, А. А. Дукин, А. Н. Смирнов та В. Г. Голубев. "Люминесцентные свойства углеродных наноточек на поверхности сферического микрорезонатора". Физика твердого тела 62, № 10 (2020): 1690. http://dx.doi.org/10.21883/ftt.2020.10.49922.102.

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Hybrid structures were synthesized from monodisperse spherical silica particles, which are spherical microcavities, and emitting carbon nanodots on their surface. Carbon nanodots are attached to the surface of the particles by controlled coagulation in three solvents: ammonia, hydrochloric acid and glycerol. Intense narrow lines associated with the emission of nanodots in the whispering gallery modes of a spherical microcavity were observed in the photoluminescence spectra of hybrid structures over the entire radiation wavelength range of carbon nanodots from UV to near IR. All observed lines were identified by comparison with the spectral positions of the whispering gallery modes calculated by the method of spherical wave transfer matrices.

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30

Yucel, Abdulkadir Cihad, Luis J. Gomez, and Eric Micielssen. "Compression of Translation Operator Tensors in FMM-FFT-Accelerated SIE Solvers via Tucker Decomposition." IEEE Antennas and Wireless Propagation Letters 16 (2017): 2667–70. http://dx.doi.org/10.1109/lawp.2017.2740363.

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31

González, Cecilia Guízar, Natali Rianika Mustafa, Erica Georgina Wilson, Robert Verpoorte, and Young Hae Choi. "Application of natural deep eutectic solvents for the “green”extraction of vanillin from vanilla pods." Flavour and Fragrance Journal 33, no. 1 (October 4, 2017): 91–96. http://dx.doi.org/10.1002/ffj.3425.

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32

Xu, Sheng. "An Iterative Two-Fluid Pressure Solver Based on the Immersed Interface Method." Communications in Computational Physics 12, no. 2 (August 2012): 528–43. http://dx.doi.org/10.4208/cicp.090211.220811s.

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AbstractAn iterative solver based on the immersed interface method is proposed to solve the pressure in a two-fluid flow on a Cartesian grid with second-order accuracy in the infinity norm. The iteration is constructed by introducing an unsteady term in the pressure Poisson equation. In each iteration step, a Helmholtz equation is solved on the Cartesian grid using FFT. The combination of the iteration and the immersed interface method enables the solver to handle various jump conditions across two-fluid interfaces. This solver can also be used to solve Poisson equations on irregular domains.

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33

Chen, Yang, Dmytro Vasiukov, Lionel Gélébart, and Chung Hae Park. "A FFT solver for variational phase-field modeling of brittle fracture." Computer Methods in Applied Mechanics and Engineering 349 (June 2019): 167–90. http://dx.doi.org/10.1016/j.cma.2019.02.017.

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34

Kallala, Haithem, Jean-Luc Vay, and Henri Vincenti. "A generalized massively parallel ultra-high order FFT-based Maxwell solver." Computer Physics Communications 244 (November 2019): 25–34. http://dx.doi.org/10.1016/j.cpc.2019.07.009.

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35

Giraud, Luc, Ronan Guivarch, and Joël Stein. "Parallel Distributed FFT-Based Solvers for 3-D Poisson Problems in Meso-Scale Atmospheric Simulations." International Journal of High Performance Computing Applications 15, no. 1 (February 2001): 36–46. http://dx.doi.org/10.1177/109434200101500104.

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36

Dieguez, Adrian Perez, Margarita Amor, Jacobo Lobeiras, and Ramon Doallo. "Solving Large Problem Sizes of Index-Digit Algorithms on GPU: FFT and Tridiagonal System Solvers." IEEE Transactions on Computers 67, no. 1 (January 1, 2018): 86–101. http://dx.doi.org/10.1109/tc.2017.2723879.

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37

Mishra, Nachiketa, Jaroslav Vondřejc, and Jan Zeman. "A comparative study on low-memory iterative solvers for FFT-based homogenization of periodic media." Journal of Computational Physics 321 (September 2016): 151–68. http://dx.doi.org/10.1016/j.jcp.2016.05.041.

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38

Cvetanovic, Zarka, Edward G. Freedman, and Charles Nofsinger. "Efficient decomposition and performance of parallel PDE, FFT, Monte Carlo simulations, simplex, and Sparse solvers." Journal of Supercomputing 5, no. 2-3 (October 1991): 219–38. http://dx.doi.org/10.1007/bf00127844.

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39

Vostrikova, Natal’ya L., Oksana A. Kuznetsova, and Andrey V. Kulikovskii. "METHODOLOGICAL ASPECTS OF LIPID EXTRACTION FROM BIOLOGICAL MATRICES." Theory and practice of meat processing 3, no. 2 (July 11, 2018): 4–21. http://dx.doi.org/10.21323/2414-438x-2018-3-2-4-21.

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Анотація:

The paper presents the studies on the degree of raw fat extraction from meat systems by various methods. Relative differences in extraction methods are shown depending on the polarity of solvents used. Fat was extracted using the classical Soxhlet method, as well as two-step extraction. Specially prepared model systems were used as test samples including both simple and multicomponent mixtures in the form of meat-and-bone meal, bone meal, and meat-and-plant meal. It was found that when using non-polar solvents, a large amount of polar lipids was lost. The influence of the solvent on the degree of extraction for glycerides, phosphatides, free fatty acids and oxidation products was shown. A number of experiments are presented and the results are given on the degree of fat extraction using mixtures of organic solvents with mineral acid. The studies allowed to choose the best extraction method for each type of meat and meat-containing raw materials. Based on the results, methodical recommendations are proposed on the use of hydrophobic and hydrophilic solvents and their mixtures. Methods of lipid extraction from food products after alkaline and acid hydrolysis are considered. Examples of fat determination by instrumental methods (refractometry) are given. Classical methods for fat content evaluation are described (Randall method, Twisselmann method, and Rushkovsky method).ContributionAll authors bear responsibility for the work and presented data. All authors made an equal contribution to the work. The authors were equally involved in writing the manuscript and bear the equal responsibility for plagiarism.Conflict of interestThe authors declare no conflict of interest.

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40

WANG, YEN-CHUN, RICHARD W. HARTEL, JUNGRO YOON, and R. SELWYN JEBSON. "EXTRACTION of MILK FAT IN HIGH PRESSURE SOLVENTS." Journal of Food Processing and Preservation 19, no. 6 (December 1995): 409–25. http://dx.doi.org/10.1111/j.1745-4549.1995.tb00304.x.

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41

Yang, Kai, and Ali E. Yilmaz. "An FFT-Accelerated Integral-Equation Solver for Analyzing Scattering in Rectangular Cavities." IEEE Transactions on Microwave Theory and Techniques 62, no. 9 (September 2014): 1930–42. http://dx.doi.org/10.1109/tmtt.2014.2335176.

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42

Lai, Jun, and Michael O'Neil. "An FFT-accelerated direct solver for electromagnetic scattering from penetrable axisymmetric objects." Journal of Computational Physics 390 (August 2019): 152–74. http://dx.doi.org/10.1016/j.jcp.2019.04.005.

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43

Staub, Sarah, Heiko Andrä, and Matthias Kabel. "Fast FFT based solver for rate-dependent deformations of composites and nonwovens." International Journal of Solids and Structures 154 (December 2018): 33–42. http://dx.doi.org/10.1016/j.ijsolstr.2016.12.014.

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44

Kabel, Matthias, Thomas Böhlke, and Matti Schneider. "Efficient fixed point and Newton–Krylov solvers for FFT-based homogenization of elasticity at large deformations." Computational Mechanics 54, no. 6 (October 1, 2014): 1497–514. http://dx.doi.org/10.1007/s00466-014-1071-8.

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45

Yang, Xuelian, Zhaoyang Pei, Wenbin Du, and Jianchun Xie. "Characterization of Volatile Flavor Compounds in Dry-Rendered Beef Fat by Different Solvent-Assisted Flavor Evaporation (SAFE) Combined with GC–MS, GC–O, and OAV." Foods 12, no. 17 (August 23, 2023): 3162. http://dx.doi.org/10.3390/foods12173162.

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Анотація:

To comprehensively understand the volatile flavor composition of dry-rendered beef fat, solvent-assisted flavor evaporation (SAFE) with four extraction solvents (dichloromethane, pentane, ethyl ether, and methanol) combined with gas chromatography–mass spectrometry (GC–MS) and gas chromatography–olfactormetry (GC–O) were performed. GC–MS analysis found 96 different volatile compounds in total using the four extraction solvents. According to the GC–MS results and the heat map and principal component analysis (PCA), most of the volatile compounds resulted from dichloromethane and pentane extraction, followed by ethyl ether. Methanol extraction found a few volatile compounds of higher polarity, which was supplementary to the analysis results. Moreover, GC–O analysis found 73 odor-active compounds in total using the four extraction solvents. The GC–O results found that pentane and dichloromethane extraction had a significantly larger number of odor-active compounds than ethyl ether and methanol extraction. This indicated that pentane and dichloromethane were more effective solvents for the extraction of odor-active compounds than the other two solvents. Finally, a total of 15 compounds of odor-active values (OAVs) ≥ 1 were determined to be the key aroma compounds in the dry-rendered beef fat, including 2–methyl–3–furanthiol, 3–methylthiopropanal, (E,E)–2,4–nonadienal, 12–methyltridecanal, and 1–octen–3–one.

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46

Bao, Weizhu, Qinglin Tang, and Yong Zhang. "Accurate and Efficient Numerical Methods for Computing Ground States and Dynamics of Dipolar Bose-Einstein Condensates via the Nonuniform FFT." Communications in Computational Physics 19, no. 5 (May 2016): 1141–66. http://dx.doi.org/10.4208/cicp.scpde14.37s.

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AbstractWe propose efficient and accurate numerical methods for computing the ground state and dynamics of the dipolar Bose-Einstein condensates utilising a newly developed dipole-dipole interaction (DDI) solver that is implemented with the non-uniform fast Fourier transform (NUFFT) algorithm. We begin with the three-dimensional (3D) Gross-Pitaevskii equation (GPE) with a DDI term and present the corresponding two-dimensional (2D) model under a strongly anisotropic confining potential. Different from existing methods, the NUFFT based DDI solver removes the singularity by adopting the spherical/polar coordinates in the Fourier space in 3D/2D, respectively, thus it can achieve spectral accuracy in space and simultaneously maintain high efficiency by making full use of FFT and NUFFT whenever it is necessary and/or needed. Then, we incorporate this solver into existing successful methods for computing the ground state and dynamics of GPE with a DDI for dipolar BEC. Extensive numerical comparisons with existing methods are carried out for computing the DDI, ground states and dynamics of the dipolar BEC. Numerical results show that our new methods outperform existing methods in terms of both accuracy and efficiency.

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47

Hendra, Surani. "Fat acid extraction from Naviculla Salinicola and Chlorella Vulgaris with simple laboratory tools." Jurnal Temapela 3, no. 2 (May 31, 2021): 65–72. http://dx.doi.org/10.25077/temapela.3.2.65-72.2020.

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Energy alternatives are starting to get attention due to the depletion of petroleum sources as the current fuel. One of them is biodiesel. Microalgae has the potential to produce fat that can be proceed into biodiesel. This study aims to find the shaking time and the suitable solvent with the extraction of microalgaes, namely Naviculla Salinicola and Chlorella Vulgaris fatty acids with various solvents, namely hexane, methanol and chloroform. Each microalgae can affect different cell walls that resulting in different extraction materials. The results showed that fatty acids Chlorella Vulgaris and Naviculla Salinicola were extracted the most with hexane. The fat content extracted from Chlorella Vulgaris with three solvents were 10.56% for hexane, 6.79% for methanol and 5.99% for chloroform. For the extraction of Naviculla salinicola with hexane solvent yielded 4.37% fat, while with choloroform was 2.99% and with methanol was 2.48%. The increase in processing time resulted in an increase in the equivalent of fat extraction in both types of microalgae with the highest one was obtained at the five-hour shaking time.

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48

Rosenthal, Ionel, Uzi Merin, Gita Popel, and Solange Bernstein. "Determination of Fat in Vegetable Foods." Journal of AOAC INTERNATIONAL 68, no. 6 (November 1, 1985): 1226–28. http://dx.doi.org/10.1093/jaoac/68.6.1226.

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Abstract The fat in vegetable foods—tree nuts, peanuts, sunflower seeds, avocado, and olives—can be determined volumetrically by acid digestion of the material and separation of the fat. The assay can be performed conveniently by using the equipment developed for fat determination of milk (Gerber method). The results agree well with those obtained by Soxhlet extraction. The advantages of using the Gerber method for vegetable foods are simplicity, speed, low operation cost, and elimination of the use of inflammable solvents.

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49

Li, Jing He, and Qing Huo Liu. "Fast Frequency-Domain Forward and Inverse Methods for Acoustic Scattering from Inhomogeneous Objects in Layered Media." Journal of Computational Acoustics 24, no. 03 (August 30, 2016): 1650008. http://dx.doi.org/10.1142/s0218396x16500089.

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The fast scattering and inverse scattering algorithms for acoustic wave propagation and scattering in a layered medium with buried objects are an important research topic, especially for large-scale geophysical applications and for target detection. There have been increasing efforts in the development of practical, accurate, and efficient means of imaging subsurface target anomalies. In this work, the acoustic scattering problem in layered media is formulated as a volume integral equation and is solved by the stabilized bi-conjugate gradient fast Fourier transform (BCGS-FFT) method. By splitting the layered medium Green’s function interacting with the induced source into a convolution and a correlation, the acoustic fields can be calculated efficiently by the FFT algorithm. This allows both the forward solution and inverse solution to be computed with only [Formula: see text] computation time per iteration, where [Formula: see text] is the number of degrees of freedom. The inverse scattering is solved using a simultaneous multiple frequency contrast source inversion (CSI). The stable convergence of this inversion process makes the multiple frequency simultaneous CSI reconstruction practical for large acoustic problems. Some representative examples are shown to demonstrate the effectiveness of the forward and inverse solvers for acoustic applications.

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50

Ibrahim, Alia Mutasim Ali. "The Variation Effect of Solvents on the Physicochemical Properties Baobab (Ophelussitularius) Seeds Oil." Open Access Journal of Agricultural Research 9, no. 1 (2024): 1–7. http://dx.doi.org/10.23880/oajar-16000347.

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It is remarkable to notice that Baobab seeds are normally discarded in Sudan, without knowing the great wealth hidden. The present study was conducted to determine physicochemical properties of Baobab (Ophelussitularis) seeds oil and select proper solvent for oil extraction from seeds which contain approximately 22-45%, used n-hexane and ethanol as solvents, leaching was done by solid extraction method. Physicochemical properties of the Baobab seeds oil were evaluated by standard and established methods. Oils and solvents were separated using rotary evaporator, recovery solvent were 91.2% and 75% for n-hexane and ethanol respectively. The obtained Baobab oils color were golden yellow (reddish yellow) not effected by type of solvent, it showed resistance to change in color, results showed the maximum Baobab oil yields were 16% and 13.5 % for n-hexane and ethanol respectively. Crude protein CP was found to be13.475 g/100 g, oil content was 13.26 g/, Saponification value SV 338.4925 g and 406.725 g/100 g for Baobab oil extracted with n-hexane and ethanol respectively. Results were obtained for ash content, crude fiber, acid value, FFA and rheological properties. Physicochemical properties indicated that n-hexane was more suitable to extract Baobab oil more than ethanol and recover easy. The difference was clearly visible in PV, AV and µ, while n-hexane yields pure oil more than ethanol. All those results detected that seeds of Baobab are beneficial if they extracted using n-hexane. It is recommended to conduct additional research on this issue and insert other solvents to select the best solvent and study the effect of different solvents on the properties of resulting oil.

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