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Rayleigh-Taylor instability under multimode perturbation:Discrete Boltzmann modeling with tracers

Communications in Theoretical Physics 2022年第11期74卷 180-198页

作者： Hanwei Li Aiguo Xu Ge Zhang Yiming Shan Laboratory of Computational Physics Institute of Applied Physics and Computational MathematicsBeijing 100088China HEDPS Center for Applied Physics and TechnologyCollege of EngineeringPeking UniversityBeijing 100871China State Key Laboratory of Explosion Science and Technology Beijing Institute of TechnologyBeijing 100081China Energy Resources Engineering Department Stanford University367 Panama StStanfordCA 94305-2220United States of America

The two-dimensional Rayleigh-Taylor Instability(RTI)under multi-mode perturbation in compressible flow is probed via the Discrete Boltzmann Modeling(DBM)with *** distribution of tracers provides clear boundaries between light and heavy fluids in the position ***,the position-velocity phase space offers a new perspective for understanding the flow behavior of RTI with intuitive geometrical *** effects of viscosity,acceleration,compressibility,and Atwood number on the mixing of material and momentum and the mean nonequilibrium strength at the interfaces are investigated separately based on both the mixedness defined by the tracers and the non-equilibrium strength defined by the *** mixedness increases with viscosity during early stage but decreases with viscosity at the later ***,compressibility,and Atwood number show enhancement effects on mixing based on different *** the system relaxes from the initial state,the mean non-equilibrium strength at the interfaces presents an initially increasing and then declining trend,which is jointly determined by the interface length and the macroscopic physical quantity *** conclude that the four factors investigated all significantly affect early evolution behavior of an RTI system,such as the competition between interface length and macroscopic physical quantity *** results contribute to the understanding of the multi-mode RTI evolutionary mechanism and the accompanied kinetic effects.

关键词： Rayleigh-Taylor instability multi-mode perturbation Discrete Boltzmann modeling tracers non-equilibrium effects kinetic modeling

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Use and application of CFC-11,CFC-12,CFC-113 and SF6 as environmental tracers of groundwater residence time:A review

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Geoscience Frontiers 2019年第5期10卷 1643-1652页

作者： L.A. Chambers D.C. Gooddy A.M. Binley Department of Civil and Environmental Engineering University of StrathclydeGlasgowG1 1XJUK Lancaster Environment Centre Lancaster UniversityLancasterLA1 4YQUK British Geological Survey Maclean BuildingWallingfordOX10 8BBUK

Groundwater residence time is a fundamental property of groundwater to understand important hydrogeological issues,such as deriving sustainable abstraction volumes,or,the evolution of groundwater *** anthropogenic trace gases chlorofluorocarbons (CFC-11,CFC-12 and CFC-113) and sulphur hexafluoride (SF6) are ideal in this regard because they have been released globally at known rates and become dissolved in groundwater following Henry’s Law,integrating over large spatial (global) and temporal (decades) *** CFCs and SF6 are able to date groundwater up to w100 years old with the caveat of certain simplifying ***,the inversion of environmental tracer concentrations (CFCs and SF6) to derive groundwater age rests on the accurate determination of groundwater recharge parameters,namely temperature,elevation,salinity and excess air,in addition to resolving the potential for contamination,degradation and unsaturated zone *** review explores the fundamentals of CFC-11,CFC-12,CFC-113 and SF6 as environmental tracers of groundwater age and recommends complementary techniques *** this relatively simple and inexpensive technique has been used to determine initial concentrations at the recharge zone,setting the groundwater dating ‘clock’ to zero,this review then explores the meaning of groundwater ‘age’ in relation to measured environmental tracer *** is shown that the CFCs and SF6 may be applied to a wide-range of hydrogeological problems and suggests that environmental tracers are particularly powerful tools when integrated with numerical flow and transport models.

关键词： Hydrogeology Environmental tracers Groundwater dating

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Spectrally adapted red flare tracers with superior spectral performance

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Defence Technology（防务技术） 2017年第6期13卷 406-412页

作者： Ramy Sadek Mohamed Kassem Mohamed Abdo Sherif Elbasuney School of Chemical Engineering Military Technical CollegeKobry ElkobaCairoEgypt

The production of bright light, with vivid color, is the primary purpose of signaling, illuminating devices,and fire control purposes. This study, reports on the development of red flame compositions with enhanced performance in terms of luminous intensity, and color quality. The light intensity and the imprint spectra of developed red flame compositions to standard NATO red tracer(R-284 NATO) were measured using digital luxmeter, and UV-Vis. spectrometer. The main giving of this study is that the light intensity of standard NATO red tracer was increased by 72%, the color quality was also improved by60%(over the red band from 650 to 780 nm). This enhanced spectral performance was achieved by means of deriving the combustion process to maximize the formation of red color emitting species in the combustion flame. Thanks to the optimum ratio of color source to color intensifier using aluminum metal fuel; this approach offered the highest intensity and color quality. Upon combustion, aluminum was found to maximize the formation SrCL(the main reactive red color emitting species) and to minimize the interfering incandescent emission resulted from MgO and SrO. Quantification of active red color emitting species in the combustion flame was conducted using chemical equilibrium thermodynamic code named ICT. The improvement in red flare performance, established the rule that the color intensifier should be in the range from 10 to 15 Wt % of the total composition.

关键词： Pyrotechnics Colored flames tracers Luminous intensity Molecular spectroscopy

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Groundwater arsenic biogeochemistry-Key questions and use of tracers to understand arsenic-prone groundwater systems

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Geoscience Frontiers 2019年第5期10卷 1635-1641页

作者： David A. Polya Charlotte Sparrenbom Saugata Datta Huaming Guo School of Earth and Environmental Sciences and Williamson Research Centre for Molecular Environmental Science The University of ManchesterWilliamson BuildingOxford RoadManchesterM13 9PLUK Department of Geology Lund UniversityLundSweden Department of Geology Kansas State University108 Thompson HallManhattanKS66506-3201USA State Key Laboratory of Biogeology and Environmental Geology and School of Water Resources China University of GeosciencesBeijing 100083China

Over 100,000,000 people worldwide are exposed to high arsenic groundwater utilised for drinking or *** consequent global avoidable disease burden is estimated to be of the order of 100,000 avoidable deaths or more per annum from just direct exposures - *** indirect exposure (from rice and other foods) and excluding *** 1000s of papers published on arsenic (hydro)(bio)geochemistry,there remain a number of key outstanding questions to be addressed in relation to arsenic geoscience - these include questions related to:(i) the role of human activities - irrigation,agriculture and other land uses - on arsenic mobilisation in groundwaters;(ii) the specific sources,nature and role of organics,minerals and microbial communities involved in arsenic mobilisation;(iii) the relationship to microscopic to macroscopic scale geological (including tectonic) and evolution processes;(iv) unravelling the over-printing of multiple processes in complex highly heterogeneous aquifer systems and (v) using increasing understanding of the controls of arsenic mobility in groundwaters systems to informing improved locally-relevant remediation and mitigation *** article further summarises how the 9 further papers in this Special Issue address some of these questions through the use of chemical and/or isotopic tracers.

关键词： Arsenic Groundwater Biogeochemical cycles tracers

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Tracing Sources of Geochemical Anomalies in a Deeply Buried Volcanic-Related Hydrothermal Uranium Deposit:the Daguanchang Deposit,Northern Hebei Province,North China Craton

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Journal of Earth Science 2024年第4期35卷 1186-1195页

作者： Yangyang Zhang Yuelong Chen Dapeng Li Huan Kang Mingliang Fang Yunliang Xu School of Earth Science and Resources China University of GeosciencesBeijing100083China State Key Laboratory of Earthquake Dynamics Institute of GeologyChina Earthquake AdministrationBeijing100083China Jinchuan Group Company Limited Jinchang737104China China-Explo Tian Cheng(Beijing)Technology Company Limited Beijing100093China

Radon(Rn)and helium(He)gases from uranium decay form distinct anomalies related to buried uranium *** order to trace the geochemical anomalous sources from the volcanic-related uranium deposits in deeply buried areas,systematical Rn contents and He isotope ratios were analyzed from the Daguanchang uranium *** soil gas Rn concentrations above the deep uranium are ten times higher than those in barren areas,indicating that instantaneous Rn content measurements can be used to detect deeply buried *** helium isotope ratios(^(3)He/^(4)He)of the unmineralized samples from the mineralized drill hole(ZK1)are relatively lower and uniform compared to those of the samples from no-mineral drill hole(ZK2).However,the Th and U contents of the drill core samples from ZK1 are slightly lower than those of the samples from ZK2,indicating that the lower 3He/4He ratios in ZK1 are most likely due to the addition of 4He from underlying uranium *** differences in the instantaneous Rn contents are consistent with the variations in the He isotope ratios of the drill core *** results demonstrate that soil gas Rn and ^(3)He/^(4)He ratios are useful tracers and can indicate the existence of deeply buried volcanic-related hydrothermal uranium ores.

关键词： tracers radon helium ^(3)He/^(4)He ratio uranium deposits Daguanchang deposit

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Structure-from-Motion Photogrammetry and Rare Earth Oxides can quantify diffuse and convergent soil loss and source apportionment

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International Soil and Water Conservation Research 2023年第4期11卷 633-648页

作者： Pia Benaud Karen Anderson Mike R.James Timothy A.Quine John N.Quinton Richard E.Brazier CREWW GeographyFaculty of EnvironmentScience and EconomyUniversity of ExeterExeterDevonEX44RJUnited Kingdom Environment and Sustainability Institute University of ExeterPenrynCornwallTR109FEUnited Kingdom Lancaster Environment Centre Lancaster UniversityBailriggLancasterLA14YQUnited Kingdom Geography Faculty of EnvironmentScience and Economy.University of ExeterExeterDevonEX44RJUnited Kingdom

Accurately quantifying rates of soil erosion requires capturing both the volumetric nature of the visible,convergent fluvial pathways(also known as rills)and the subtle nature of the less-visible,diffuse pathways(interrill areas).The aim of this study was to use Rare Earth Oxide(REO)tracers and Structure-from-Motion(SfM)photogrammetry to elucidate retrospective information about soil erosion rates and sediment sources during different soil erosion conditions,within a controlled laboratory *** experimental conditions created erosion events consistent with diffuse and convergent erosion *** tracers allowed the sediment transport distances of over 2 m to be described,and helped resolved the relative contribution of diffuse and convergent soil erosion;interrill areas were also iden-tified as a significant sediment sources soil loss under convergent erosion *** the potential for SfM photogrammetry to resolve sub-millimetre elevations changes was demonstrated,under some conditions non-erosional changes in surface elevation,such as compaction,exceeded volumes of soil loss via diffuse *** discrepancies between SfM Photogrammetry calculations and REO tagged sediment export were beneficial,identifying that during soil erosion events sediment in both aggregate and particle form is deposited within the convergent features,even when the rill extended the full length of the soil *** combination of SfM photogrammetry and REO tracers has provided a novel platform for building a spatial understanding of patterns of soil loss and source apportionment between rill and interrill erosion.

关键词： Soil erosion Structure-from-Motion Photogrammetry Rare Earth Oxides tracers Sediment Rainfall simulator Sheetwash Rilling Interrill

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Treatment and hydraulic performances of the NiiMi process for landscape water

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2010年第2期11卷 132-142页

作者： Jian YANG Liang-bo ZHANG Yi-fan WU Ya-yi WANG Cui LI Wen LIU State Key Laboratory of Pollution Control and Resources Reuse School of Environmental Science and Engineering Tongji University Shanghai 200092 China

This paper describes the NiiMi process designed to treat landscape water. The main aim of the research was to investigate the feasibility of NiiMi for removing organic and nutriment materials from landscape water. During the batch-scale NiiMi operation, the removal rates of color ranged from 66.7%o-80% , of turbidity from 31.7%-89.3%o, of chemical oxygen demand （COD） from 7%-36.5%, of total phosphor （TP） from 43%-84.2%, of soluble phosphate from 42.9%-100%, of total nitrogen （TN） from 4.2%-46.7%, and of NH4^＋-N from 39.3%-100% at the hydraulic loading of 0.2 m^3/（m^2·d）. Results showed that the removal efficiencies of COD, TP, soluble phosphate and TN decreased with the decline in the temperature. The NiiMi process had a strong shock loading ability for the removal of the organics, turbidity, TP, soluble phosphate, TN and NH4^＋-N. Three sodium chloride tracer studies were conducted, labeled as TS 1, TS2, and TS3, respectively. The mean hydraulic retention times （mean HRTs） were 31 h and 28 h for TSI and TS2, respectively, indicating the occurrence of a dead zone volume of 12% and 20% for TS 1 and TS2, respectively. TS 1 and TS2 displayed the occurrence of short-circuiting in the NiiMi system. The comparison results between TS1 and TS2 were further confirmed in the values obtained for some indicators, such as volumetric efficiency （e）, short-circuiting （S）, hydraulic efficiency （2） and number of continuously stirred tank reactors （N）.

关键词： NiiMi system Landscape water Purification efficiency Hydraulic efficiency tracers

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Tracking characteristics of tracer particles for PIV measurements in supersonic flows

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Chinese Journal of Aeronautics 2017年第2期30卷 577-585页

作者： Chen Fang Liu Hong Yang Zifeng Hu Hui School of Aeronautics and Astronautics Shanghai Jiao Tong University Department of Mechanical and Materials Engineering Wright State University Department of Aerospace Engineering Iowa State University

The tracking characteristics of tracer particles for particle image velocimetry（PIV） measurements in supersonic flows were *** experimental tests were conducted at Mach number 4 in Multi-Mach Wind Tunnel（MMWT） of Shanghai Jiao Tong *** motion of tracer particles carried by the supersonic flow across Shockwaves was theoretically modelled,and then their aerodynamic characteristics with compressibility and rarefaction effects were *** to the proposed selection criterion of tracer particles,the PIV measured results clearly identified that the Shockwave amplitude is in good agreement with theory and Schlieren *** the tracer particles in nanoscales,their effective aerodynamic sizes in the diagnostic zone can be faithfully estimated to characterize the tracking capability and dispersity performance based on their relaxation motion across oblique *** the other hand,the seeding system enabled the tracer particles well-controlled and repeatable dispersity against the storage and humidity.

关键词： Particle Image Velocimetry(PIV) Seeding Supersonic flow tracers Tracking characteristics

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Arsenic variability and groundwater age in three water supply wells in southeast New Hampshire

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Geoscience Frontiers 2019年第5期10卷 1669-1683页

作者： Joseph P.Levitt James R.Degnan Sarah M.Flanagan Bryant C.Jurgens U.S.Geological Survey

Three wells in New Hampshire were sampled bimonthly over three years to evaluate the temporal variability of arsenic concentrations and groundwater *** samples had measurable concentrations of arsenic throughout the entire sampling period and concentrations in individual wells had a mean variation of more than 7 μg/*** time series data from this sampling effort showed that arsenic concentrations ranged from a median of 4 mg/L in a glacial aquifer well (SGW-65) to medians of 19 μg/L and 37 μg/L in wells (SGW-93 and KFW-87) screened in the bedrock aquifer,*** high arsenic concentrations were associated with the consistently high pH (median ≥- 8) and low dissolved oxygen (median <0.1 mg/L) in the bedrock aquifer wells,which is typical of fractured crystalline bedrock aquifers in New *** from the glacial aquifer often has high dissolved oxygen,but in this case was consistently *** pH also is generally acidic in the glacial aquifer but in this case was slightly alkaline (median =7.5).Also,sorption sites may be more abundant in glacial aquifer deposits than in fractured bedrock which may contribute to lower arsenic *** groundwater ages were less than 50 years old in all three wells and correlated with conservative tracer concentrations,such as chloride;however,mean age was not directly correlated with arsenic *** concentrations at KFW-87 did correlate with water levels,in addition,there was a seasonal pattern,which suggests that either the timing of or multiple sampling efforts may be important to define the full range of arsenic concentrations in domestic bedrock *** geochemically reduced conditions and alkaline pHs are common to both bedrock and glacial aquifer wells in this study,groundwater age correlates less strongly with arsenic concentrations than geochemical *** also is evidence of direct hydraulic connection between the glacial and bedrock aquifers,which can influe

关键词： Arsenic variability Geochemical time series Age tracers Groundwater age modeling

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Theoretical Proof and Empirical Confirmation of a Continuous Labeling Method Using Naturally ^13C-Depleted Carbon Dioxide

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Journal of Integrative Plant Biology 2007年第3期49卷 401-407页

作者： Weixin Cheng Feike A. Dijkstra Environmental Studies University of California Santa Cruz CA 95064 USA

Continuous Isotope labeling and tracing is often needed to study the transformation, movement, and allocation of carbon in plant-soil systems. However, existing labeling methods have numerous limitations. The present study Introduces a new continuous labeling method using naturally ^13C-depleted CO2. We theoretically proved that a stable level of ^13C-CO2 abundance in a labeling chamber can be maintained by controlling the rate of CO2-free air Injection and the rate of ambient airflow with coupling of automatic control of CO2 concentration using a CO2 analyzer. The theoretical results were tested and confirmed in a 54 day experiment in a plant growth chamber. This new continuous labeling method avoids the use of radioactive ^14C or expensive ^13C-enrlched CO2 required by existing methods and therefore eliminates issues of radiation safety or unaffordable isotope cost, as well as creating new opportunities for short- or long-term labeling experiments under a controlled environment.

关键词： carbon flux CO2 isotope rhizosphere tracers

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