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Analysis of particle dispersion and cavity formation during bulk particle water entry using fully coupled CFD-DEM-vOF approach

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Particuology 2024年第7期90卷 558-580页

作者： Utkan Çalışkan Sanja Mišković Norman B.Keevil Institute of Mining Engineering University of British Columbia2329 West MallVancouverBC V6T 1Z4Canada

This paper presents the development and validation of a fully coupled computational fluid dynamics—discrete element method—volume of fluid(CFD-DEM-vOF)model to simulate the complex behavior of particle-laden flows with free *** coupling between the fluid and particle phases is established through the implemented continuity,momentum,and alpha transport *** coupled particle forces such as drag,pressure gradient,dense virtual mass,viscous,and interface forces are also integrated,with drag and dense virtual mass forces being dependent on local *** integrated conservative alpha transport equation ensures phase volume conservation during interactions between particles and ***,we have implemented a trilinear interpolation method designed to operate on unstructured hexahedral *** method has been tested for its ability to properly resolve the coupling effects in the numerical simulations,particularly in cases with a relatively low cell-size *** model is validated through three distinct test cases:single particle water entry,dam break with particles,and water entry of a group of particles *** experimental setup is built to study the dynamics of the water entry of a group of particles,where three key flow features are analyzed:the evolution of average particle velocity,cavity shape,and particle dispersion cloud profiles in *** tests involve four different scenarios,including two different water levels(16.1 and 20.1 cm)and two different particle densities(2650 and 4000 kg/m3).High-speed videometry and particle tracking velocimetry(using ImageJ/TrackMate)methods are employed for experimental data *** is demonstrated that numerical results are in excellent agreement with theoretical predictions and experimental *** study highlights the significance of vortices in cavity shaping and particle *** validated CFD-DEM-vOF model constitutes a robust tool for simulating particle-laden flows,cont

关键词： CFD-DEM-vOF Trilinear interpolation Particle-laden flow Free-surface Particle water entry volume conservation

Exploring impacts of COvID-19 on spatial and temporal patterns of visitors to Canadian Rocky Mountain National Parks from social media big data

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Journal of Forestry Research 2024年第4期35卷 13-33页

作者： Dehui Christina Geng Amy Li Jieyu Zhang Howie W.Harshaw Christopher Gaston Wanli Wu Guangyu Wang National Park Research Centre Faculty of ForestryUniversity of British ColumbiaVancouver V6T 1Z4Canada Faculty of Applied Science University of British ColumbiaVancouver V6T 1Z3Canada Paul G.Allen School of Computer Science&Engineering University of WashingtonSeattleWA 98195USA Faculty of Kinesiology Sportand RecreationUniversity of AlbertaEdmonton T6G 2J9Canada Department of Wood Science Faculty of ForestryUniversity of British ColumbiaVancouver V6T 1Z4Canada

COvID-19 posed challenges for global tourism *** in visitor temporal and spatial patterns and their associated determinants pre-and peri-pandemic in Canadian Rocky Mountain National Parks are *** was collected through social media programming and analyzed using spatiotemporal analysis and a geographically weighted regression(GWR)*** highlight that COvID-19 significantly changed park visitation *** tended to explore more remote areas *** GWR model also indicated distance to nearby trails was a significant influence on visitor *** results indicate that the pandemic influenced tourism temporal and spatial *** research presents a novel approach using combined social media big data which can be extended to the field of tourism management,and has important implications to manage visitor patterns and to allocate resources efficiently to satisfy multiple objectives of park management.

关键词： Tourism management Social media big data National parks COvID-19 Geographical weighted regression

Assembly structures of coastal woody species of eastern South America:Patterns and drivers

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Plant Diversity 2024年第5期46卷 611-620页

作者： Eduardo vinícius da Silva Oliveira Myrna Friederichs Landim Sidney F.Gouveia Graduate Program in Ecology and Conservation Federal University of SergipeSão CristovãoSergipeBrazil National Institute of Science and Technology Ecology Evolution and Conservation of Biodiversity(INCT-EECBio)GoiâniaGoiasBrazil Department of Biology Federal University of SergipeSão CristóvãoSergipeBrazil Department of Ecology Federal University of SergipeSão CristóvãoSergipeBrazil

Tropical regions have provided new insights into how ecological communities are *** dry coastal communities,water stress has been hypothesized to determine plant assembly structure by favoring preadapted lineages from neighboring ecosystems,consistent with functional ***,it is unclear whether this hypothesis is sufficient to explain how coastal communities in tropical ecosystems are ***,we test whether water stress or other factors drive community assembly in woody plant communities across the coastal zone of Brazil,a tropical *** characterized functional and phylogenetic structures of these communities and determined the underlying environmental factors(e.g.,water stress,historical climate stability,edaphic constraints,and habitat heterogeneity)that drive their community *** of coastal woody species show geographically varied patterns,including stochastic arrangements,clustering,and overdispersion of species relative to their traits and phylogenetic *** complexity,water vapor pressure,and soil nutrient availability best explained the gradient in the functional *** deficit,water vapor pressure,and soil organic carbon were the best predictors of variation in phylogenetic *** results support the water-stress conservatism hypothesis on functional and phylogenetic structure,as well as the effect of habitat heterogeneity on functional structure and edaphic constraints on functional and phylogenetic *** effects are associated with increased phenotypic and phylogenetic divergence of woody plant assemblages,which is likely mediated by abiotic filtering and niche opportunities,suggesting a complex pattern of ecological assembly.

关键词： Brazil Completeness Clustering Restinga vegetation Water constraints

Decentralized Proof-of-Burn auction for secure cryptocurrency upgrade

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Blockchain(Research and Applications) 2024年第1期5卷 50-57页

作者： Mariia Rodinko Roman Oliynykov Andrii Nastenko IOG 4 Battery Road049908Singapore v.N.Karazin Kharkiv National University 4 Svobody Sq.Kharkiv61022Ukraine

We propose a new approach for a secure,decentralized,and censorless upgrade of existing cryptocurrencies to newly created tokens without interaction with any external information sources(oracles).The proposed scheme is based on the burning of existing cryptocurrency tokens and implemented via the multi-currency *** auction is carried out on the blockchain of the new token and implemented using a smart contract that processes participants’bids of burnt tokens of other cryptocurrencies and supports a new token price discovery algorithm for each cryptocurrency with no oracles or any other trusted source of *** to traditional ways of getting the new asset,like centralized and decentralized exchanges,our method requires no user registration(as well as no KYC-“know your customer”procedure that requires obligatory client identification)and provides a predicted supply level of the new asset for an adequate price within a model with economically rational *** provide the results of decentralized auction simulations implemented for several strategies of user behavior(based on bid prices with normal and log-normal distribution laws),both under the normal operation and in the presence of an adversary who follows specific strategies.

关键词： Proof-of-Burn Blockchain Cryptocurrency Auction Token

Laser-induced plasma formation in water with up to 400 mJ double-pulse LIBS

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Plasma Science and Technology 2024年第1期26卷 93-100页

作者： Marion HENKEL Michelle SIEMENS Ralf METHLING Benjamin EMDE Jörg HERMSDORF Steffen FRANKE Diego GONZALEZ Leibniz Institute for Plasma Science and Technology(INP) Felix-Hausdorff-Straße 2Greifswald 17489Germany Laser Zentrum Hannover e.v.(LZH) Hollerithallee 8Hannover 30419Germany

Double-pulse LIBS is a promising technique for deep-sea *** measurements in shallow water with up to 400 mJ each pulse were done to select laser parameters which promote optimized spectral line emission from plasma even at elevated pressures,where line broadening until loss of most of the spectral information can *** emission spectroscopy,using a Czerny-Turner spectrometer,has been applied to investigate the dependence of the emitted radiation on laser parameters and hydrostatic *** has been found,that higher laser pulse energies,especially with short pulse delay as required in high water pressure,can also have an adverse effect on the measured spectrum.

关键词： double-pulse LIBS underwater plasma formation emission spectrosocpy

Exploring Capillary Fringe Flow:Quasilinear Modeling with Kirchhoff Transforms and Gardner Model

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Fluid Dynamics & Materials Processing 2024年第7期20卷 1611-1631页

作者： Rachid Karra Abdelatif Maslouhi LASTIMI Laboratory Mohammadia School of EngineersMohammed V University in RabatRabatMorocco LIRNE Laboratory Faculty of SciencesIbn Tofail UniversityKenitraMorocco

Recent studies have underscored the significance of the capillary fringe in hydrological and biochemical ***,its role in shallow waters is expected to be ***,the study of groundwater flow has centered on unsaturated-saturated zones,often overlooking the impact of the capillary *** this study,we introduce a steady-state two-dimensional model that integrates the capillary fringe into a 2-D numerical *** novel approach employs the potential form of the Richards equation,facilitating the determination of boundaries,pressures,and velocities across different ground surface *** utilized a two-dimensional Freefem++finite element model to compute the stationary *** validation of the model was conducted using experimental *** employed the OFAT(One_Factor-At-Time)method to identify the most sensitive soil parameters and understand how changes in these parameters may affect the behavior and water dynamics of the capillary *** results emphasize the role of hydraulic conductivity as a key parameter influencing capillary fringe shape and *** values within the capillary fringe suggest the prevalence of horizontal *** variation of the water table level and the incoming flow q0,we have shown the correlation between water table elevation and the upper limit of the capillary fringe.

关键词： Capillary fringe Freefem++ gardner model modeling porous media

On stability behaviors of 5D M-theory black objects

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Communications in Theoretical Physics 2024年第5期76卷 94-101页

作者： Adil Belhaj Abderrahim Bouhouch Departement de Physique Equipe des Sciences de la matiere et du rayonnementESMaR Faculte des SciencesUniversite Mohammed V de RabatRabatMorocco

Using N=2 supergravity formalism,we investigate certain behaviors of five-dimensional black objects from the compactification of M-theory on a Calabi-Yau *** manifold has been constructed as the intersection of two homogeneous polynomials of degrees(ω+2,1)and(2,1)in a product of two weighted projective spaces given by WP^(4)(ω,1,1,1,1)×P^(1).First,we determine the allowed electric charge regions of the BPS and non BPS black holes obtained by wrapping M2-branes on appropriate two cycles in such a proposed Calabi-Yau *** that,we calculate the entropy of these solutions which takes a maximal value corresponding to ω=1 defining the ordinary projective space P^(4).For generic values of ω,we show that the non BPS states are ***,we conduct a similar study of five-dimensional black *** the allowed magnetic charge regions of the BPS and non BPS black stringy solutions derived from M5-branes on dual divisors,we calculate the tension taking a minimal value for P^(4).By determining the recombination factor,we show that the non-BPS black string states are stable in the allowed regions in the magnetic charge space.

关键词： M-theory Calabi-Yau manifolds black holes black strings stability behaviors

Life under tension: the relevance of force on biological polymers

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Biophysics Reports 2024年第1期10卷 48-56页

作者： Matthew T.J.Halma Longfu Xu Department of Physics and Astronomy and Laser Lab Vrije Universiteit Amsterdam LUMICKS B.v.

Optical tweezers have elucidated numerous biological processes, particularly by enabling the precise manipulation and measurement of tension. One question concerns the biological relevance of these experiments and the generalizability of these experiments to wider biological systems. Here, we categorize the applicability of the information garnered from optical tweezers in two distinct categories: the direct relevance of tension in biological systems, and what experiments under tension can tell us about biological systems, while these systems do not reach the same tension as the experiment, still, these artificial experimental systems reveal insights into the operations of biological machines and life processes.

关键词： Tension Optical tweezers Molecular force

Carbon cathode with heteroatom doping and ultrahigh surface area enabling enhanced capacitive behavior for potassium-ion hybrid capacitors

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Rare Metals 2024年第5期43卷 2136-2149页

作者： Yan Xiong Ya-Fei Zhang Chun-Liu Zhu Lei Yang Huan-Yu Liang Jing Shi Jing-Wei Chen Wei-QianTian Shuai Liu Zhi Li Jing-Yi Wu Huan-Lei Wang School of Materials Science and Engineering Ocean University of ChinaQingdao 266100China Department of Chemical and Materials Engineering University of AlbertaEdmontonAB T6G 2V4Canada

Potassium-ion hybrid capacitors(PIHCs)are widely regarded as highly promising energy storage devices,due to their exceptional energy density,impressive power density,and abundant potassium ***,restricted by the inherent capacitive storage mechanism,the carbon cathodes possess a much lower specific capacity than battery-type ***,designing high-performance carbon cathodes is extremely urgent for the development of ***,N,O codoped porous carbon(NOPC)was fabricated through the NaCl hard template method and combined KOH/melamine chemical activation technique,displaying the characteristics of abundant N/O content(4.7 at%/16.9 at%),ultrahigh specific surface area(3092 m^(2)g^(-1))and hierarchical pore *** designed NOPC cathode delivers a high specific capacity(164.4 mAh.g^(-1)at 0.05 A.g^(-1))and superior cyclability(95.1%retention ratio at 2 A·g^(-1)over 2500 cycles).Notably,the adjustable ratio of micropores to mesopores facilitates the achievement of the optimal bal-ance between capacity and rate ***,the pseudocapacitance can be further augmented through the incorporation of N/O functional *** expected,the graphite//NOPC based PIHC possesses a high energy density of 113 Wh·kg-at 747 W·kg^(-1)and excellent capacity retention of 84.4% fter 400 cycles at 1.0 A·g^(-1).This work introduces a novel strategy for designing carbon cathodes that enhances the electrochemical performance of PIHCs.

关键词： Template method N/O co-doping High specific surface area Carbon cathode Potassium-ion capacitors