scholarly journals An object-oriented particle tracking code for pyrite oxidation and pollutant transport in mine spoil heaps

2007 ◽  
Vol 9 (4) ◽  
pp. 293-304 ◽  
Author(s):  
C. J. Gandy ◽  
P. L. Younger
Keyword(s):  
Particle Tracking ◽  
Ferrous Iron ◽  
Transport Model ◽  
Pyrite Oxidation ◽  
Object Oriented ◽  
Oxidation Products ◽  
Mine Spoil ◽  
Spoil Heap ◽  
Tracking Model ◽  
Spoil Heaps

A physically based contaminant transport model, POTOMAC (Pyrite Oxidation products Transport: Object-oriented Model for Abandoned Colliery sites), has been developed to simulate the pyrite oxidation process in mine spoil heaps and the subsequent transport of the reaction products. This is believed to represent the first particle tracking model created using object-oriented technology and has proved capable of simulating the large time scales (on the order of centuries) required for this application. The model conceptualises a spoil heap as a series of ‘columns’, each representing a portion of the unsaturated zone, where active weathering and precipitation of secondary minerals takes place. The columns are then connected to a saturated zone, beneath the water table, where the contaminants are transported to the heap discharge. A form of particle tracking, the ‘random walk method’, is used to transport both the oxidant, oxygen, and the products, ferrous iron and sulfate. The subsequent oxidation of ferrous iron and precipitation of ferric oxyhydroxide is incorporated to provide an iron ‘sink’, where iron is effectively removed from the transport process. The application of POTOMAC to a case study, the Morrison Busty spoil heap in County Durham, UK, has produced encouraging results.

scholarly journals Mineralogical, numerical and analytical studies of the coupled oxidation of pyrite and coal

2003 ◽  
Vol 67 (2) ◽  
pp. 381-398 ◽  
Author(s):  
K. A. Evans ◽  
C. J. Gandy ◽  
S. A. Banwart
Keyword(s):  
Reactive Transport ◽  
Transport Model ◽  
Pyrite Oxidation ◽  
Spoil Heap ◽  
Reaction Fronts ◽  
Order Of Magnitude ◽  
Magnitude Variation ◽  
Discharge Chemistry ◽  
Analytical Expressions

Mineralogical, bulk and field leachate compositions are used to identify important processes governing the evolution of discharges from a coal spoil heap in County Durham. These processes are incorporated into a numerical one-dimensional advective-kinetic reactive transport model which reproduces field results, including gas compositions, to within an order of magnitude. Variation of input parameters allows the effects of incorrect initial assumptions on elemental profiles and discharge chemistry to be assessed. Analytical expressions for widths and speeds of kinetic reaction fronts are developed and used to predict long-term development of mineralogical distribution within the heap. Results are consistent with observations from the field site. Pyrite oxidation is expected to dominate O2 consumption in spoil heaps on the decadal timescale, although C oxidation may stabilize contaminants in effluents on the centennial scale.

scholarly journals Effect of bathymetric changes on residence time in Buenaventura bay (Colombia)

DYNA ◽  
2019 ◽  
Vol 86 (211) ◽  
pp. 241-248
Author(s):  
Francisco Fernando Garcia Renteria ◽  
Mariela Patricia Gonzalez Chirino
Keyword(s):  
Finite Elements ◽  
Residence Time ◽  
Particle Tracking ◽  
Hydrodynamic Model ◽  
Residence Times ◽  
Particle Tracking Model ◽  
Tracking Model ◽  
Bathymetric Changes

In order to study the effects of dredging on the residence time of the water in Buenaventura Bay, a 2D finite elements hydrodynamic model was coupled with a particle tracking model. After calibrating and validating the hydrodynamic model, two scenarios that represented the bathymetric changes generated by the dredging process were simulated. The results of the comparison of the simulated scenarios, showed an important reduction in the velocities fields that allow an increase of the residence time up to 12 days in some areas of the bay. In the scenario without dredging, that is, with original bathymetry, residence times of up to 89 days were found.

scholarly journals Wind Tunnel Validation of a Particle Tracking Model to Evaluate the Wind-Induced Bias of Precipitation Measurements.

2020 ◽  
Author(s):  
Arianna Cauteruccio ◽  
Elia Brambilla ◽  
Mattia Stagnaro ◽  
Luca Giovanni Lanza ◽  
Daniele Rocchi
Keyword(s):  
Wind Tunnel ◽  
Particle Tracking ◽  
Particle Tracking Model ◽  
Tracking Model

Study on the existence of the transportation particle tracking model in the interactive medium

2021 ◽  
pp. 2150256
Author(s):  
Mohamed Abd Allah El-Hadidy ◽  
Alaa A. Alzulaibani
Keyword(s):  
Waiting Time ◽  
Particle Tracking ◽  
Necessary Conditions ◽  
Particle Detection ◽  
Particle Tracking Model ◽  
Search Plan ◽  
Tracking Process ◽  
Unit Speed ◽  
Tracking Model ◽  
Interactive Medium

This paper assumes that the particle jumps randomly (Guassian jumps) from one point to another along one of the imaginary lines inside the interactive medium. Since this study was done in the space, we consider that the position of the particle at any time [Formula: see text] has a multivariate distribution. The random waiting time of the particle for each Gaussian jump depends on its length. An identical set of programed nanosensors (with unit speed) were used to track this particle. Each line has a sensor that starts the tracking process from the origin. The existence of the necessary conditions which give the optimal search plan and the minimum expected value of the particle detection has been proven. This study is supported by a numerical example.

scholarly journals Secondary organic aerosol in the global aerosol – chemistry transport model Oslo CTM2

2007 ◽  
Vol 7 (3) ◽  
pp. 9053-9092 ◽  
Author(s):  
C. R. Hoyle ◽  
T. Berntsen ◽  
G. Myhre ◽  
I. S. A. Isaksen
Keyword(s):  
Ammonium Sulphate ◽  
Secondary Organic Aerosol ◽  
Transport Model ◽  
Model Simulation ◽  
Anthropogenic Activities ◽  
Organic Aerosol ◽  
Oxidation Products ◽  
Total Production ◽  
Chemical Transport Model ◽  
Sulphate Aerosol

Abstract. The global chemical transport model Oslo CTM2 has been extended to include the formation, transport and deposition of secondary organic aerosol (SOA). Precursor hydrocarbons which are oxidised to form condensible species include both biogenic species such as terpenes and isoprene, as well as species emitted predominantly by anthropogenic activities (toluene, m-xylene, methylbenzene and other aromatics). A model simulation for 2004 gives an annual global SOA production of approximately 55 Tg. Of this total, 2.5 Tg is found to consist of the oxidation products of anthropogenically emitted hydrocarbons, and about 15 Tg is formed by the oxidation products of isoprene. The global production of SOA is increased to about 76 Tg yr−1 by allowing semi-volatile species to condense on ammonium sulphate aerosol. This brings modelled organic aerosol values closer to those observed, however observations in Europe remain significantly underestimated, raising the possibility of an unaccounted for SOA source. Allowing SOA to form on ammonium sulphate aerosol increases the contribution of anthropogenic SOA from about 4.5% to almost 9% of the total production. The importance of NO3 as an oxidant of SOA precursors is found to vary regionally, causing up to 50%–60% of the total amount of SOA near the surface in polluted regions and less than 25% in more remote areas. This study underscores the need for SOA to be represented in a more realistic way in global aerosol models in order to better reproduce observations of organic aerosol burdens in industrialised and biomass burning regions.

scholarly journals Characterization of a real-time tracer for isoprene epoxydiols-derived secondary organic aerosol (IEPOX-SOA) from aerosol mass spectrometer measurements

2015 ◽  
Vol 15 (20) ◽  
pp. 11807-11833 ◽  
Author(s):  
W. W. Hu ◽  
P. Campuzano-Jost ◽  
B. B. Palm ◽  
D. A. Day ◽  
A. M. Ortega ◽  
...  
Keyword(s):  
Mass Spectrometer ◽  
Secondary Organic Aerosol ◽  
Transport Model ◽  
Organic Aerosol ◽  
Oxidation Products ◽  
Chemical Transport Model ◽  
Aerosol Mass Spectrometer ◽  
Aerosol Mass ◽  
Multiple Field

Abstract. Substantial amounts of secondary organic aerosol (SOA) can be formed from isoprene epoxydiols (IEPOX), which are oxidation products of isoprene mainly under low-NO conditions. Total IEPOX-SOA, which may include SOA formed from other parallel isoprene oxidation pathways, was quantified by applying positive matrix factorization (PMF) to aerosol mass spectrometer (AMS) measurements. The IEPOX-SOA fractions of organic aerosol (OA) in multiple field studies across several continents are summarized here and show consistent patterns with the concentration of gas-phase IEPOX simulated by the GEOS-Chem chemical transport model. During the Southern Oxidant and Aerosol Study (SOAS), 78 % of PMF-resolved IEPOX-SOA is accounted by the measured IEPOX-SOA molecular tracers (2-methyltetrols, C5-Triols, and IEPOX-derived organosulfate and its dimers), making it the highest level of molecular identification of an ambient SOA component to our knowledge. An enhanced signal at C5H6O+ (m/z 82) is found in PMF-resolved IEPOX-SOA spectra. To investigate the suitability of this ion as a tracer for IEPOX-SOA, we examine fC5H6O (fC5H6O= C5H6O+/OA) across multiple field, chamber, and source data sets. A background of ~ 1.7 ± 0.1 ‰ (‰ = parts per thousand) is observed in studies strongly influenced by urban, biomass-burning, and other anthropogenic primary organic aerosol (POA). Higher background values of 3.1 ± 0.6 ‰ are found in studies strongly influenced by monoterpene emissions. The average laboratory monoterpene SOA value (5.5 ± 2.0 ‰) is 4 times lower than the average for IEPOX-SOA (22 ± 7 ‰), which leaves some room to separate both contributions to OA. Locations strongly influenced by isoprene emissions under low-NO levels had higher fC5H6O (~ 6.5 ± 2.2 ‰ on average) than other sites, consistent with the expected IEPOX-SOA formation in those studies. fC5H6O in IEPOX-SOA is always elevated (12–40 ‰) but varies substantially between locations, which is shown to reflect large variations in its detailed molecular composition. The low fC5H6O (< 3 ‰) reported in non-IEPOX-derived isoprene-SOA from chamber studies indicates that this tracer ion is specifically enhanced from IEPOX-SOA, and is not a tracer for all SOA from isoprene. We introduce a graphical diagnostic to study the presence and aging of IEPOX-SOA as a triangle plot of fCO2 vs. fC5H6O. Finally, we develop a simplified method to estimate ambient IEPOX-SOA mass concentrations, which is shown to perform well compared to the full PMF method. The uncertainty of the tracer method is up to a factor of ~ 2, if the fC5H6O of the local IEPOX-SOA is not available. When only unit mass-resolution data are available, as with the aerosol chemical speciation monitor (ACSM), all methods may perform less well because of increased interferences from other ions at m/z 82. This study clarifies the strengths and limitations of the different AMS methods for detection of IEPOX-SOA and will enable improved characterization of this OA component.

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