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34th General Assembly and Scientific Symposium of the International Union of Radio Science, URSI GASS 2021

作者： Chartier, Alex T. Datta-Barua, Seebany McDonald, Sarah E. Johns Hopkins University/Applied Physics Laboratory LaurelMD20723 United States Illinois Institute of Technology Mechanical Materials and Aerospace Engineering Department ChicagoIL60616 United States

ISBN: (纸本)9789463968027

The Ionospheric Data Assimilation Four-Dimensional (IDA4D) technique has been coupled to Sami3 is Another Model of the Ionosphere (SAMI3). In this application, ground-and space-based GPS Total Electron Content (TEC) data have been assimilated into SAMI3 while in situ electron densities, autoscaled ionosonde NmF2 and reference GPS stations have been used for validation. IDA4D/SAMI3 shows that Night-time Ionospheric Localized Enhancements (NILE) are formed following geomagnetic storms in November 2003 and August 2018. The NILE phenomenon appears as a moderate, longitudinally extended enhancement of NmF2 at 30-40° N MLAT, occurring in the late evening (20-24 LT) following much larger enhancements of the equatorial anomaly crests in the main phase of the storms. The NILE appears to be caused by upward and northward plasma transport around the dusk terminator, which is consistent with eastward polarization electric fields. Independent validation confirms the presence of the NILE, and indicates that IDA4D is effective in correcting random errors and systematic biases in SAMI3. In all cases, biases and root-mean-square errors are reduced by the data assimilation, typically by a factor of 2 or more. During the most severe part of the November 2003 storm, the uncorrected ionospheric error on a GPS 3D position at 1LSU (Louisiana) is estimated to exceed 34 m. The IDA4D/SAMI3 specification is effective in correcting this down to 10-m. © 2021 URSI.

关键词： Storms

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Recent Advancements in Nanophotonics for Optofluidics

arXiv

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arXiv 2024年

作者： Yang, Sen Hong, Chuchuan Zhu, Guodong Anyika, Theodore Hong, Ikjun Ndukaife, Justus C. Institute of Physics Chinese Academy of Sciences Beijing National Laboratory for Condensed Matter Physics Beijing100190 China Department of Chemistry Department of Materials Science and Engineering Northwestern University EvanstonIL60208 United States Department of Electrical and Computer Engineering Vanderbilt University NashvilleTN37235 United States Department of Mechanical Engineering Vanderbilt University NashvilleTN37235 United States Interdisciplinary Materials Science Program Vanderbilt University NashvilleTN37240 United States

Optofluidics is dedicated to achieving integrated control of particle and fluid motion, particularly on the micrometer scale, by utilizing light to direct fluid flow and particle motion. The field has seen significant growth recently, driven by the concerted efforts of researchers across various scientific disciplines, notably for its successful applications in biomedical science. In this review, we explore a range of optofluidic architectures developed over the past decade, with a primary focus on mechanisms for precise control of micro and nanoscale biological objects and their applications in sensing. Regarding nanoparticle manipulation, we delve into mechanisms based on optical nanotweezers using nanolocalized light fields and light-based hybrid effects with dramatically improved performance and capabilities. In the context of sensing, we emphasize those works that used optofluidics to aggregate molecules or particles to promote sensing and detection. Additionally, we highlight emerging research directions, encompassing both fundamental principles and practical applications in the field. Copyright © 2024, The Authors. All rights reserved.

关键词： Flow of fluids

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Bacterial Mobility and Motility in Porous Media Mimicked By Microspheres

SSRN

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SSRN 2022年

作者： Shrestha, Diksha Ou, Jun Rogers, Ariel Jereb, Amani Wang, Yong Department of Physics Cell and Molecular Graduate Program Materials Science and Engineering Program University of Arkansas FayettevilleAR72701 United States Department of Environmental Resources Engineering Mechanical Engineering Program California State Polytechnic University Humboldt ArcataCA95521 United States

Bacterial motion in porous media are essential for their survival, proper functioning, and variousapplications. Here we investigated the motion of Escherichia coli bacteria in microsphere-mimicked porousmedia. We observed reduced bacterial velocity and enhanced directional changes of bacteria as the densityof microspheres increased, while such changes happened mostly around the microspheres and due to thecollisions with the microspheres. More importantly, we established and quantified the correlation betweenthe bacterial trapping in porous media and the geometric confinement imposed by the microspheres. In addition,numerical simulations showed that the active Brownian motion model in the presence of microspheresresulted in bacterial motion that are consistent with the experimental observations. Our study suggested thatit is important to distinguish the ability of bacteria to move easily – bacterial mobility – from the abilityof bacteria to move independently – bacteria motility. Our results showed that bacterial motility remainssimilar in porous media, but bacterial mobility was significantly affected by the pore-scale confinement. © 2022, The Authors. All rights reserved.

关键词： Microspheres

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First-principles determination of the phonon-point defect scattering and thermal transport due to fission products in ThO2

引用

Physical Review Materials 2024年第2期8卷 025401-025401页

作者： Linu Malakkal Ankita Katre Shuxiang Zhou Chao Jiang David H. Hurley Chris A. Marianetti Marat Khafizov Computational Mechanics and Materials Department Idaho National Laboratory Idaho Falls Idaho 83415 USA Department of Scientific Computing Modeling and Simulation SP Pune University Pune 411007 India Idaho National Laboratory Idaho Falls Idaho 83415 USA Department of Applied Physics and Applied Mathematics Columbia University 500 West 120th Street New York New York 10027 USA Department of Mechanical and Aerospace Engineering The Ohio State University 201 West 19th Avenue Columbus Ohio 43210 USA

This work presents the first-principles calculations of the lattice thermal conductivity degradation due to point defects in thorium dioxide using an iterative solution of the Peierls-Boltzmann transport equation. We have used the nonperturbative Green's function methodology to compute the phonon-point defect scattering rates that consider the local distortion around the point defect, including the mass difference changes, interatomic force constants, and structural relaxation near the point defects. The point defects considered in this work include the vacancy of thorium (VTh) and oxygen (VO), substitutions of helium (HeTh), krypton (KrTh), zirconium (ZrTh), iodine (ITh), and xenon (XeTh) in the thorium site, and the three different configurations of the Schottky defects. The results of the phonon-defect scattering rate reveal that among all the considered intrinsic defects, the thorium vacancy and helium substitution in the thorium site scatter the phonon most due to the substantial changes in the force constant and structural distortions. The scattering of phonons due to the substitutional defects unveils that the zirconium atom scatters phonons the least, followed by xenon, iodine, krypton, and helium. This is contrary to the intuition that the scattering strength follows HeTh>KrTh>ZrTh>ITh>XeTh based on the mass difference. This striking difference in the zirconium phonon scattering is due to the local chemical environment changes. Zirconium is an electropositive element with valency similar to thorium and, therefore, can bond with the oxygen atoms, thus creating less force constant variance compared to iodine, an electronegative element, and the noble gases helium, xenon, and krypton. These results can serve as a benchmark for analytical models and help the engineering-scale modeling effort for nuclear design.

关键词： Carrier dynamics Energy materials Heat transfer Irradiation effects Lattice dynamics Nuclear power Phonons Thermal conductivity Thermal properties

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Tracking Sargassum in the Caribbean: The Deployment and Validation of a Low-Cost Surface Drifter

SSRN

引用

SSRN 2023年

作者： Pixa, Chase Manganini, Kevin Myers, Alyson Michel, Anna P.M. Department of Applied Ocean Physics and Engineering Woods Hole Oceanographic Institution 266 Woods Hole Road Woods HoleMA02543 United States Department of Mechanical Engineering Massachusetts Institute of Technology 77 Massachusetts Ave CambridgeMA02139 United States MIT-WHOI Joint Program in Oceanography/Applied Ocean Science & Engineering Cambridge and Woods Hole MA United States Fearless Fund 3029 Woodland Drive NW WashingtonDC20008 United States

Sargassum blooms have been causing significant ecological and economic damage to coastal regions in the Northern Equatorial Atlantic since 2011. To better understand the movement and effects of this macroalgae, there is a need to track its transport. In this study, a low-cost drifter was deployed, designed to entangle with Sargassum and aid in its tracking. The design was based on the results of twenty-seven drifter designs and five days of field trials. The tracking data was validated using gridded wind and current products, as well as high resolution satellite imagery. The successful entanglement and tracking with the Sargassum demonstrated in this study can provide in situ movement data to ground-truth models and supplement gaps in satellite imaging. The results can guide future studies and further our understanding of its movement in the great Atlantic Sargassum belt (GASB). © 2023, The Authors. All rights reserved.

关键词： Costs

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Spatio-temporal characterization of non-linear forcing in turbulence

arXiv

引用

arXiv 2023年

作者： Huang, Yuting Toedtli, Simon S. Chini, Gregory P. McKeon, Beverley J. Graduate Aerospace Laboratories California Institute of Technology PasadenaCA91125 United States Department of Mechanical Engineering Johns Hopkins University BaltimoreMD21218 United States Program in Integrated Applied Mathematics University of New Hampshire DurhamNH03824 United States Department of Mechanical Engineering University of New Hampshire DurhamNH03824 United States Department of Mechanical Engineering Stanford University StanfordCA94305 United States

The quadratic convection term in the incompressible Navier-Stokes equations is considered as a non-linear forcing to the linear operator, and it is studied in the Fourier domain through the analysis of interactions between triadically compatible wavenumber-frequency triplets. Interaction coefficients are proposed to quantify the contribution to the forcing by each pair of triplets and are computed using data from direct numerical simulations of a turbulent channel at Reτ ≈ 550. The coefficients show the importance of interactions involving streamwise large scales. The regions of non-linear interactions permitted under the quasi-linear (QL) and generalized quasi-linear (GQL) assumptions are shown to be significant contributors to the forcing and increasing the number of GQL-large scales is shown to monotonically increase the total forcing captured, providing a possible reason for the success of QL and GQL simulations. The tools presented are expected to be useful for improving modeling of the nonlinearity, especially in QL, GQL, and resolvent analyses, and understanding the amplitude modulation mechanism relating large-scale fluctuations to the modulation of near-wall structures. Copyright © 2023, The Authors. All rights reserved.

关键词： Turbulence

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Artificial Chemistry Performed in an Agglomeration of Droplets with Restricted Molecule Transfer 16th

Artificial Chemistry Performed in an Agglomeration of Dro...

引用

16th Italian Workshop on Artificial Life and Evolutionary Computation, WIVACE 2022

作者： Schneider, Johannes Josef Faggian, Alessia Jamieson, William David Weyland, Mathias Sebastian Li, Jin Castell, Oliver Matuttis, Hans-Georg Barrow, David Anthony Diaz, Aitor Patiño Sanahuja, Lorena Cebolla Holler, Silvia Casiraghi, Federica Hanczyc, Martin Michael Flumini, Dandolo Eggenberger Hotz, Peter Füchslin, Rudolf Marcel Institute of Applied Mathematics and Physics School of Engineering Zurich University of Applied Sciences Technikumstr. 9 Winterthur8401 Switzerland School of Engineering Cardiff University Queen’s Buildings 14-17 The Parade CardiffCF24 3AA United Kingdom University of Trento Trento38123 Italy Department of Mechanical Engineering and Intelligent Systems The University of Electrocommunications Chofu Chofugaoka 1-5-1 Tokyo182-8585 Japan Chemical and Biological Engineering University of New Mexico MSC01 1120 AlbuquerqueNM87131-0001 United States European Centre for Living Technology S.Marco 2940 Venice30124 Italy

ISBN: (纸本)9783031311826

Within the scope of the European Horizon 2020 project ACDC – Artificial Cells with Distributed Cores to Decipher Protein Function, we aim at the development of a chemical compiler governing the three-dimensional arrangement of droplets, which are filled with various chemicals. Neighboring droplets form bilayers with pores which allow chemicals to move from one droplet to its neighbors. With an appropriate three-dimensional configuration of droplets, we can thus enable gradual biochemical reaction schemes for various purposes, e.g., for the production of macromolecules for pharmaceutical purposes. In this paper, we demonstrate with artificial chemistry simulations that the ACDC technology is excellently suitable to maximize the yield of desired reaction products or to minimize the relative output of unwanted side products. © 2023, The Author(s), under exclusive license to Springer Nature Switzerland AG.

关键词： Agglomeration

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Lattice Boltzmann Simulation of Magnetic Field Effect on Electrically Conducting Fluid at Inclined Angles in Rayleigh-Bénard Convection

引用

Energy engineering 2021年第1期118卷 15-36页

作者： T.Ahmed S.Hassan M.F.Hasan M.M.Molla M.A.Taher S.C.Saha Department of Mathematics and Physics North South UniversityDhaka1229Bangladesh Center for Applied Scientific Computing(CASC) North South UniversityDhaka1229Bangladesh Department of Engineering&Physical Sciences La Trobe UniversityMelbourneVIC 3086Australia Department of Mathematics Dhaka University of Science and TechnologyGazipurBangladesh School of Mechanical and Mechatronic Engineering University of Technology SydneyUltimoAustralia

The magneto-hydrodynamics(MHD)effect is studied at different inclined angles in Rayleigh-Bénard(RB)convection inside a rectangular enclosure using the lattice Boltzmann method(LBM).The enclosure is filled with electrically conducting fluids of different *** characteristics are defined by Prandtl number,*** considered Pr values for this study are 10 and *** influence of other dimensionless parameters Rayleigh numbers Ra=10^(3);10^(4);10^(5);10^(6) and Hartmann numbers Ha=0,10,25,50,100,on fluid flow and heat transfer,are also investigated considering different inclined anglesφof magnetic field by analyzing computed local Nusselt numbers and average Nusselt *** results of the study show the undoubted prediction capability of LBM for the current *** simulated results demonstrate that the augmentation in heat transfer is directly related to Ra values,but it is opposite while observing the characteristics of Ha ***,it is also found thatφhas a significant impact on heat transfer for different ***,isotherms are found to be always parallel to the horizontal axis at Ra=10^(3) as conduction overcomes the convection in the heat transfer,but this behaviour is not seen at Ra=10^(4) when Ha>***,at Ra=10^(6),oscillatory instability appears but LBM is still able to provide a complete map of this predicted beha*** appropriate validation with previous numerical studies demonstrates the accuracy of the present approach.

关键词： Average rate of heat transfer Hartmann number lattice Boltzmann method magnetic field effect Rayleigh-Bernard convection

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Discovery of Ni Activated Sintering of MoNbTaW Predicted by a Computed Grain Boundary Diagram

SSRN

引用

SSRN 2023年

作者： Shivakumar, Sashank Song, Keqi Wang, Chunyang Lei, Tianjiao Xin, Huolin L. Rupert, Timothy J. Luo, Jian Department of Nano and Chemical Engineering Program of Materials Science and Engineering University of California San Diego La Jolla CA92093 United States Department of Physics and Astronomy University of California IrvineCA92697 United States Department of Materials Science and Engineering Department of Mechanical and Aerospace Engineering University of California IrvineCA92697 United States

Activated sintering of refractory metals represents a classical phenomenon in powder metallurgy. This study discovers that Ni addition can enhance sintering of MoNbTaW both above and below the bulk solidus composition at 1800 °C, thereby demonstrating the first example of activated sintering of a high-entropy alloy. To probe the underlying mechanism, experiments reveal complete grain boundary (GB) wetting above the bulk solidus composition, which logically infers the stabilization of a liquid-like interfacial phase (GB complexion) in a prewetting region below the bulk solidus composition. Furthermore, bulk CALPHAD (calculation of phase diagram) methods have been extended to model GBs in Ni-doped MoNbTaW to compute a GB "phase" diagram to forecast high-temperature GB disordering in the prewetting region and rationalize the observed Ni activated sintering of MoNbTaW. Only weak GB segregation of Ni is found in furnace-cooled specimens, which suggests GB "drying" during cooling, consistent with the observed nanoscale precipitates along GBs. © 2023, The Authors. All rights reserved.

关键词： Grain boundaries

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Recent progress in MgB_(2)superconducting joint technology

引用

Journal of Magnesium and Alloys 2023年第7期11卷 2217-2229页

作者： Hao Liang Dipak Patel Mahboobeh Shahbazi Andrzej Morawski Daniel Gajda Matt Rindfleisch Richard Taylor Yusuke Yamauchi Md Shahriar A.Hossain School of Mechanical and Mining Engineering The University of QueenslandSt LuciaQueensland 4072Australia QUT Centre for Materials Science and School of Chemistry and Physics Queensland University of TechnologyBrisbaneQueensland 4001Australia Institute of High Pressure Physics Polish Academy of Sciences(PAS)Sokolowska 29/37Warsaw 01-142Poland Institute of Low Temperature and Structure Research Polish Academy of Sciences(PAS)Okólna 2Wrocław 50-422Poland Hyper Tech Research Inc.539 Industrial Mile RdColumbusOhio 43228USA Applied Superconductivity Laboratory Queensland University of TechnologyBrisbaneQueensland 4001Australia Australian Institute for Bioengineering and Nanotechnology(AIBN) The University of QueenslandSt LuciaQueensland 4072Australia Department of Materials Process Engineering Graduate School of EngineeringNagoya UniversityFuro-choChikusa-kuNagoya 464-8603Japan The Commonwealth Scientific and Industrial Research Organisation(CSIRO) LindfieldNew South Wales 2070Australia

Magnesium diboride(MgB_(2))magnets have the potential to be the next-generation liquid-helium-free magnet for magnetic resonance imaging(MRI)application due to their relatively high superconducting transition temperature,high current density and low raw material cost compared with current commercial niobium-titanium(Nb-Ti)magnets.A typical superconducting magnet includes several *** produce an ultra-stable magnetic field for imaging in MRI,a superconducting electromagnet operating in a persistent mode is *** coils of the electromagnet in MRI are short-circuited to operate in the persistent mode by connecting coils with superconducting ***-sistent joints have been demonstrated for in-situ and ex-situ wires of both mono-and multi-filamentary structures,made predominantly by PIT techniques similar to those used in wire *** realise further engagement of MgB_(2)in MRI applications,enhancing the performance of MgB_(2)superconducting joints is *** literature review summarises research and development on MgB_(2)superconducting joining technology.

关键词： MgB_(2) Superconducting joints Persistent-mode magnets MRI application Field-decay measurement

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