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1. Numerical exploration of hydrodynamic features in a methanol-to-olefins fluidized bed reactor with two parallel reaction zones

Author:
Zhang, Chunhua; Wang, Fenfen; Lu, Bona; Wang, Wei; Liu, Mengxi; Lu, Chunxi
Source:
Powder technology 2020 v.372 pp. 336-350
ISSN:
0032-5910
Subject:
tracer techniques,   etc   ; fluidized beds; hydrodynamics; models;     Show all 4 Subjects
Abstract:
... A novel methanol-to-olefins (MTO) reactor in which two parallel reaction zones were created by introducing a draft tube to a column bed was numerically investigated using a combination of multi-fluid model and two types of EMMS drags, in order to explore the favorable hydrodynamics. The further numerical comparison of the novel reactor and a conventional reactor found that the introduction of a dr ...
DOI:
10.1016/j.powtec.2020.06.010

2. LIF or dye: Comparison of different tracing methods for granular solids

Author:
Scheibelhofer, Otto; Kruisz, Julia; Rehrl, Jakob; Faulhammer, Eva; Witschnigg, Andreas; Khinast, Johannes G.
Source:
Powder technology 2020 v.367 pp. 20-31
ISSN:
0032-5910
Subject:
tracer techniques,   etc   ; cameras; dyes; fluorescence; photometers;     Show all 5 Subjects
Abstract:
... Determination of residence time distribution is considered essential for continuous pharmaceutical unit operations, in order to enable process understanding and control. A common way for determining residence times are tracer based methods, yet at the moment most realizations are found in liquid systems whereas use of those methods on granular samples is rarely encountered.Here, we compare two dif ...
DOI:
10.1016/j.powtec.2020.03.033

3. Longitudinal and transverse dispersion coefficients of 2D contaminant transport model for mixing analysis in open channels

Author:
Shin, Jaehyun; Seo, Il Won; Baek, Donghae
Source:
Journal of hydrology 2020 v.583 pp. 124302
ISSN:
0022-1694
Subject:
tracer techniques,   etc   ; dispersibility; equations; hydrology; mixing; models;     Show all 6 Subjects
Abstract:
... In this study, longitudinal and transverse dispersion coefficients of the two-dimensional advection-dispersion model were calculated using both the velocity and concentration data obtained through tracer tests in large-scale meandering channels. The velocity-based dispersion coefficients calculated by applying the theoretical equations to the velocity data were compared with concentration-based di ...
DOI:
10.1016/j.jhydrol.2019.124302

4. Particles residence time distribution in a gas-solid cyclone reactor using a CFD-DDPM tracer method

Author:
Li, Anjun; Zhu, Liyun; Wang, Kun; Wang, Guotao; Wang, Zhenbo
Source:
Powder technology 2020 v.364 pp. 205-217
ISSN:
0032-5910
Subject:
tracer techniques,   etc   ; Reynolds number; hydrodynamics; models;     Show all 4 Subjects
Abstract:
... The simulation of particles residence time distribution (RTD) in a gas-solid cyclone reactor (GSCR) based on the CFD-DDPM tracer method was conducted. The comparison between the computed results and the experimental data shows that this model is applicable to predict the gas-solid hydrodynamics with better accuracy. Simulated results depict that the predicted particles RTD will be more accurate if ...
DOI:
10.1016/j.powtec.2019.11.038

5. Model and experimental study of relationship between solid fraction and back-mixing in a fluidized bed

Author:
Zhang, Chenxi; Li, Shuyue; Wang, Zhiguo; Shen, Yansong; Wei, Fei
Source:
Powder technology 2020 v.363 pp. 146-151
ISSN:
0032-5910
Subject:
tracer techniques,   etc   ; Peclet number; equations; fluidized beds; models; potential energy;     Show all 6 Subjects
Abstract:
... Residence time distribution (RTD) is a key issue of many chemical reactors, and the degree of back-mixing determines the reaction conversion and selectivity. In the present study, the relationship between time-average solids fraction and back-mixing behavior has been carefully investigated by experimental and model study. A 2-D dispersion model is introduced to describe RTD and the back-mixing in ...
DOI:
10.1016/j.powtec.2019.12.053

6. Calibration of random fields by a sequential spectral turning bands method

Author:
Lauzon, Dany; Marcotte, Denis
Source:
Computers & geosciences 2020 v.135 pp. 104390
ISSN:
0098-3004
Subject:
tracer techniques,   etc   ; algorithms; asymmetry; case studies; computers; kriging; reproduction;     Show all 7 Subjects
Abstract:
... A new algorithm for calibration of conditional realizations to measured or desired response functions is presented. The Sequential-Spectral Turning Bands Method (S-STBM) builds the field by choosing the phase of each new cosine function such that the observed field response functions become increasingly calibrated. The phase selection has little influence on the spatial correlation structure but c ...
DOI:
10.1016/j.cageo.2019.104390

7. Numerical simulation of solute transport and structural analysis for groundwater connection medium based on the tracer test

Author:
Wu, J.; Li, S. C.; Xu, Z. H.; Zhang, L. W.
Source:
Water and environment journal 2020 v.34 no.1 pp. 143-152
ISSN:
1747-6585
Subject:
tracer techniques,   etc   ; groundwater; karsts; pipelines; simulation models; solutes; water analysis;     Show all 7 Subjects
Abstract:
... Solute transport characteristics and groundwater connection structures are mainly studied in this paper by adopting the numerical simulation and field tracer test. Firstly, the simulation method of solute transport is proposed. Then two kinds of representative geological models of tracer test are built, and the process of solute transport is simulated. The variation characteristics of solute trans ...
DOI:
10.1111/wej.12449

8. Advection pathways at the Mt. Cimone WMO-GAW station: Seasonality, trends, and influence on atmospheric composition

Author:
Brattich, E.; Orza, J.A.G.; Cristofanelli, P.; Bonasoni, P.; Marinoni, A.; Tositti, L.
Source:
Atmospheric environment 2020 v.234 pp. 117513
ISSN:
1352-2310
Subject:
tracer techniques,   etc   ; advection; atmospheric chemistry; cluster analysis; emissions; lead; meteorological parameters; particulates; radionuclides; Arctic region; Italy;     Show all 11 Subjects
Abstract:
... Relationships are analysed between advection pathways and atmospheric composition at the high-mountain station of Mt. Cimone (Italy), between 1998 and 2011. Back-trajectory cluster analysis identifies eight main advection pathways. A connection is demonstrated between the seasonality of airmass transport and atmospheric composition. Temporal trends and correlation of variables, flow types and tele ...
DOI:
10.1016/j.atmosenv.2020.117513

9. Artificial and natural radionuclides in cryoconite as tracers of supraglacial dynamics: Insights from the Morteratsch glacier (Swiss Alps)

Author:
Baccolo, Giovanni; Nastasi, Massimiliano; Massabò, Dario; Clason, Caroline; Di Mauro, Biagio; Di Stefano, Elena; Łokas, Edyta; Prati, Paolo; Previtali, Ezio; Takeuchi, Nozomu; Delmonte, Barbara; Maggi, Valter
Source:
Catena 2020 v.191 pp. 104577
ISSN:
0341-8162
Subject:
tracer techniques,   etc   ; glaciers; half life; hydrology; inorganic carbon; radioactivity; radionuclides; sediments; Alps region; Switzerland;     Show all 10 Subjects
Abstract:
... Cryoconite, a sediment found on the surface of glaciers, is known for its ability to accumulate radionuclides. New data on cryoconite from the Morteratsch glacier (Switzerland) are presented to shed light on the mechanisms that control the distribution of radioactivity in cryoconite. Among the radionuclides detected in our samples, we have identified ¹⁰⁸ᵐAg, an artificial species which has never b ...
DOI:
10.1016/j.catena.2020.104577

10. Metabolic flux analysis and fluxomics-driven determination of reaction free energy using multiple isotopes

Author:
Xu, Jimmy; Martien, Julia; Gilbertson, Cole; Ma, Junyu; Amador-Noguez, Daniel; Park, Junyoung O
Source:
Current opinion in biotechnology 2020 v.64 pp. 151-160
ISSN:
0958-1669
Subject:
tracer techniques,   etc   ; Gibbs free energy; carbon; carbon metabolism; mass spectrometry; metabolic flux analysis; metabolites; stable isotopes;     Show all 8 Subjects
Abstract:
... Metabolite concentrations, fluxes, and free energies constitute the basis for understanding and controlling metabolism. Mass spectrometry and stable isotopes are integral tools in quantifying these metabolic features. For absolute metabolite concentration and flux measurement, ¹³C internal standards and tracers have been the gold standard. In contrast, no established methods exist for comprehensiv ...
DOI:
10.1016/j.copbio.2020.02.018

11. Molecularly imprinted microspheres based multiplexed fluorescence method for simultaneous detection of benzimidazoles and pyrethroids in meat samples

Author:
Cai, Yi; He, Xin; Cui, Peng Lei; Yuan, Wan Zhe; Wang, Jian Ping; Liu, Jing
Source:
Food chemistry 2020 v.319 pp. 126539
ISSN:
0308-8146
Subject:
tracer techniques,   etc   ; beef; benzimidazoles; detection limit; drugs; fluorescence; microparticles; molecular imprinting; mutton; pyrethrins; wavelengths;     Show all 11 Subjects
Abstract:
... Two molecularly imprinted microspheres and two fluorescent tracers for benzimidazoles and pyrethroids were synthesized respectively. The two types of microspheres were coated in the wells of conventional microplate simultaneously. Then the sample extracts and the two traces were added for differential competition. The fluorescence intensities at two different emission wavelengths were excited and ...
DOI:
10.1016/j.foodchem.2020.126539

12. Low-concentration tracer tests to measure air-water interfacial area in porous media

Author:
Brusseau, Mark L.; Lyu, Ying; Yan, Ni; Guo, Bo
Source:
Chemosphere 2020 v.250 pp. 126305
ISSN:
0045-6535
Subject:
tracer techniques,   etc   ; analytical methods; drainage; miscible displacement; models; porous media; saturated flow; surface tension;     Show all 8 Subjects
Abstract:
... The aqueous-based interfacial tracer method employing miscible-displacement tests is one method available for measuring air-water interfacial areas. One potential limitation to the method is the impact of tracer-induced drainage on the system. The objective of this study was to investigate the efficacy of a low-concentration tracer test method for measuring air-water interfacial area. Tracer conce ...
DOI:
10.1016/j.chemosphere.2020.126305

13. Morphology-transport relationships in liquid chromatography: Application to method development in size exclusion chromatography

Author:
Gritti, Fabrice; Hochstrasser, Janika; Svidrytski, Artur; Hlushkou, Dzmitry; Tallarek, Ulrich
Source:
Journal of chromatography 2020 v.1620 pp. 460991
ISSN:
0021-9673
Subject:
tracer techniques,   etc   ; diffusivity; gel chromatography; hydrodynamics; microstructure; models; polystyrenes; porosity; scanning electron microscopy; tetrahydrofuran; tomography;     Show all 11 Subjects
Abstract:
... We present relationships between the multiscale structure and the separation properties of size exclusion chromatography (SEC) columns. Physical bed reconstructions of wall and bulk regions from a 2.1 mm i.d. column packed with fully porous 1.7 µm bridged-ethyl hybrid (BEH) particles, obtained by focused ion-beam scanning electron microscopy, serve as geometrical models for the packing microstruct ...
DOI:
10.1016/j.chroma.2020.460991

14. Impact of low-head dams on bedload transport rates in coarse-bedded streams

Author:
Casserly, Colm M.; Turner, Jonathan N.; O'Sullivan, John J.; Bruen, Michael; Bullock, Craig; Atkinson, Siobhán; Kelly-Quinn, Mary
Source:
The Science of the total environment 2020 v.716 pp. 136908
ISSN:
0048-9697
Subject:
tracer techniques,   etc   ; bedload; empirical research; habitats; models; prioritization; radio frequency identification; remediation; sediments; streams; wavelengths; Ireland;     Show all 12 Subjects
Abstract:
... This paper presents an empirical study that uses the movement of RFID tracers to investigate the impacts of low-head dams on solid transport dynamics in coarse-bedded streams. Here we report on the influence of two structures located in Ireland's South-East, both of which indicate that particles greater than the reach D₉₀ can be carried through and over low-head dams. This observation suggests tha ...
DOI:
10.1016/j.scitotenv.2020.136908

15. Development and application of an advection-dispersion model for data analysis of electromigration experiments with intact rock cores

Author:
Meng, Shuo; Li, Xiaodong; Siitari-Kauppi, Marja; Liu, Longcheng
Source:
Journal of contaminant hydrology 2020 v.231 pp. 103618
ISSN:
0169-7722
Subject:
tracer techniques,   etc   ; diffusivity; electric potential difference; electroosmosis; ions; models; radionuclides; selenites; sorption; uncertainty;     Show all 10 Subjects
Abstract:
... An advection-dispersion model was developed for interpreting the experimental results of electromigration in granitic rock cores. The most important mechanisms governing the movement of the tracer ions, i.e. electromigration, electroosmosis and dispersion were taken into account by the advection-dispersion model, but the influence of aqueous chemistry was ignored. An analytical solution in the Lap ...
DOI:
10.1016/j.jconhyd.2020.103618

16. 90Sr and 137Cs as tracers of oceanic eddies in the sea of Japan/East sea

Author:
Hirose, Katsumi; Povinec, Pavel P.
Source:
Journal of environmental radioactivity 2020 v.216 pp. 106179
ISSN:
0265-931X
Subject:
tracer techniques,   etc   ; cesium radioisotopes; diffusivity; models; radioactivity; strontium; temporal variation; Sea of Japan;     Show all 8 Subjects
Abstract:
... Vertical distributions of ⁹⁰Sr and ¹³⁷Cs in Sea of Japan/East Sea (SOJ/ES) water in the period of 1977–2010 exhibited a typical diffusion shape with surface/subsurface maxima and decreasing values with increasing depth. Apparent vertical diffusion coefficients (AVDCs) and apparent initial surface fluxes (AIFs) of ⁹⁰Sr and ¹³⁷Cs, which were estimated using a curve-fitting method from a vertical dif ...
DOI:
10.1016/j.jenvrad.2020.106179

17. Topical Collection: Hydrogeology of a cold-region watershed near Umiujaq (Nunavik, Canada)

Author:
Lemieux, Jean-Michel; Fortier, Richard; Molson, John; Therrien, René; Ouellet, Michel
Source:
Hydrogeology journal 2020 v.28 no.3 pp. 809-812
ISSN:
1431-2174
Subject:
tracer techniques,   etc   ; groundwater; groundwater flow; hydrogeochemistry; hydrogeology; hydrologic cycle; mathematical models; permafrost; surface water; watersheds; Quebec;     Show all 11 Subjects
Abstract:
... A cold-region watershed located in the discontinuous permafrost zone near Umiujaq (Nunavik, Canada) was studied in order to increase understanding of the subarctic water cycle and permafrost dynamics. This essay gives an overview of the research, summarised in a collection of six papers that: respectively characterize the physical three-dimensional cryo-hydrogeological system, present a detailed w ...
DOI:
10.1007/s10040-020-02131-z

18. Hydrodynamics of a hydroponic bed bioreactor with different substrate media

Author:
Recsetar, Matthew S.; Cuello, Joel L.; Fitzsimmons, Kevin M.
Source:
Ecological engineering 2020 v.149 pp. 105744
ISSN:
0925-8574
Subject:
tracer techniques,   etc   ; bioreactors; clay; containers; electrical conductivity; hydrodynamics; hydroponics; mixing; sodium chloride; volcanic rocks; water flow;     Show all 11 Subjects
Abstract:
... Water flow through hydroponic media beds has seldom been characterized, and little is understood about the effects of different substrate media and flow rates as they pertain to mixing within. The hydrodynamics of four hydroponic substrate media were assessed in a small-scale hydroponic media bed bioreactor using tracer tests and mixing tests. Four media commonly used in hydroponic media beds, inc ...
DOI:
10.1016/j.ecoleng.2020.105744

19. Water sources for root water uptake: Using stable isotopes of hydrogen and oxygen as a research tool in agricultural and agroforestry systems

Author:
Penna, Daniele; Geris, Josie; Hopp, Luisa; Scandellari, Francesca
Source:
Agriculture, ecosystems & environment 2020 v.291 pp. 106790
ISSN:
0167-8809
Subject:
tracer techniques,   etc   ; agroforestry; climatic factors; hydrogen; oxygen; population growth; stable isotopes; water management; water uptake;     Show all 9 Subjects
Abstract:
... Understanding water sources for crop water uptake in agricultural and agroforestry systems is an essential step to develop more efficient and sustainable water management strategies, which is increasingly important in the light of current world population growth, changing climatic conditions and consequent growing pressures on agricultural- and agroforestry production. Stable isotopes of hydrogen ...
DOI:
10.1016/j.agee.2019.106790

20. Environmental tracer evidence for connection between shallow and bedrock aquifers and high intrinsic susceptibility to contamination of the conterminous U.S. glacial aquifer

Author:
Solder, John E.; Jurgens, Bryant; Stackelberg, Paul E.; Shope, Christopher L.
Source:
Journal of hydrology 2020 v.583 pp. 124505
ISSN:
0022-1694
Subject:
tracer techniques,   etc   ; aquifers; bedrock; groundwater; models; sediments; statistical analysis; water supply; wells; United States;     Show all 10 Subjects
Abstract:
... Covering a large portion of the northern conterminous United States (1.87 × 10⁶ km²), the glacial aquifer serves as the primary water supply for 30 million public and domestic water users. Mean groundwater age, groundwater age distribution, and susceptibility to land surface contamination, using a new metric (Susceptibility Index; SI) based on the full age distribution and less prone to bias than ...
DOI:
10.1016/j.jhydrol.2019.124505