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- Particle Transport in Fractures (5)
- Discontinuous Gas Phase in PM (4)
- Electrohydraulic Discharge (4)
- DNAPLs in Fractures (2)
- Amendment Delivery in Porous Media (1)
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- Aperture Characterization (1)
- Colloid transport (1)
- Differential transport (1)
- Dispersion (1)
- Equivalent fracture aperture solute transport tracer test mass balance aperture cubic law aperture hydraulic aperture (1)
- Multivariate Analyses (1)
- NAPL dissolution Spontaneous gas expansion Unstable gas flow Buoyancy forces Capillary forces Gas injection (1)
- Non-aqueous phase liquid Gas phase expansion Dissolution mass flux Tetrachloroethene Dichloroethene Groundwater (1)
- Single fracture (1)
- Variable-aperture fracture (1)
- Velocity distributn assioumption (1)
- Water Security (1)
Articles 1 - 19 of 19
Full-Text Articles in Engineering
Identifying The Retention Mechanisms Of (Bio)Colloids In Single, Saturated, Variable-Aperture Fractures, Sandrina Rodrigues
Identifying The Retention Mechanisms Of (Bio)Colloids In Single, Saturated, Variable-Aperture Fractures, Sandrina Rodrigues
Sarah E Dickson
No abstract provided.
The Influence Of Hydrodynamic Forces On The Transport And Retention Of Colloids In Single Saturated Dolomitic Limestone Fractures, Mike Schutten
The Influence Of Hydrodynamic Forces On The Transport And Retention Of Colloids In Single Saturated Dolomitic Limestone Fractures, Mike Schutten
Sarah E Dickson
No abstract provided.
A Comparison Of Biocolloid And Colloid Transport In Single Saturated Rock Fractures, Junlei Qu
A Comparison Of Biocolloid And Colloid Transport In Single Saturated Rock Fractures, Junlei Qu
Sarah E Dickson
No abstract provided.
Removal Of Perchlorate (Clo4-) From Water Using Pulsed Arc Electrohydraulic Discharge (Paed), Sarah E. Dickson
Removal Of Perchlorate (Clo4-) From Water Using Pulsed Arc Electrohydraulic Discharge (Paed), Sarah E. Dickson
Sarah E Dickson
No abstract provided.
New Observations Of Gas-Phase Expansion Above A Dense Non-Aqueous Phase Liquid Pool, Kevin G. Mumford, James E. Smith, Sarah E. Dickson
New Observations Of Gas-Phase Expansion Above A Dense Non-Aqueous Phase Liquid Pool, Kevin G. Mumford, James E. Smith, Sarah E. Dickson
Sarah E Dickson
The partitioning of volatile dense nonaqueous phase liquid (DNAPL) compounds to a discontinuous gas phase results in the repeated expansion, fragmentation, and vertical mobilization of gas clusters. This process has the potential to significantly affect the dissolution of DNAPL source zones and the characterization of DNAPL-contaminated sites, but has not been included in common conceptual models. This study presents new observations of discontinuous gas-phase growth above a 1,1,1-trichloroethane pool in a two-dimensional flow cell packed with 1.1-mm diameter sand. In contrast to the behavior observed in coarse glass beads, these visualization results show that the gas phase evolves as a …
Influence Of Aperture Field Heterogeneity And Anisotropy On Dispersion Regimes And Dispersivity In Single Fractures, Qinghuai Zheng, Sarah E. Dickson, Yiping Guo
Influence Of Aperture Field Heterogeneity And Anisotropy On Dispersion Regimes And Dispersivity In Single Fractures, Qinghuai Zheng, Sarah E. Dickson, Yiping Guo
Sarah E Dickson
A 33 factorial experimental design was implemented to numerically investigate the interactive effect of the mean (μ b ), standard deviation (σ b ), and anisotropic ratio (AR) (λ b x /λ b y ) of single-fracture apertures on dispersion regimes (specifically Taylor dispersion and geometric dispersion) and dispersivity. The Reynolds equation was solved to obtain the flow fields in each computer-generated fracture, and the random walk particle tracking method was used to simulate solute transport. The simulation results show that (1) for a fixed hydraulic gradient, the dominant dispersion regime is controlled by μ b , and to a …
Differential Transport And Dispersion Of Colloids Relative To Solutes In Single Fractures, Qinghuai Zheng, Sarah E. Dickson, Yiping Guo
Differential Transport And Dispersion Of Colloids Relative To Solutes In Single Fractures, Qinghuai Zheng, Sarah E. Dickson, Yiping Guo
Sarah E Dickson
This work employed numerical experiments simulating colloid and solute transport in single parallelplate fractures, using the random walk particle tracking method, to demonstrate that (1) there exists an aspect ratio of the colloid radius to half the fracture aperture, do, where the average velocities of colloids and solutes are similar. When d > do, the velocity distribution assumption is satisfied, and the fact that the ratio of the colloid transport velocity to the solute transport velocity, sp, decreases as d increases is well documented in the literature. However, when d < do, the velocity distribution assumption is violated, and sp increases as d increases and (2) the Taylor dispersion coefficient and its extension by James and Chrysikopoulos [S.C. James, C. V. Chrysikopoulos, J. Colloid Interface Sci. 263 (2003) 288] will overestimate the colloid dispersion coefficient significantly. Additionally, numerical experiments simulating colloid and solute transport in variable-aperture fractures demonstrated that sp and DL,coll /DL,solute decrease with increasing CoV, and the anisotropy ratio only plays a minor role compared to the CoV. These observations have important implications towards the interpretation of colloid transport in both porous and fractured media.
Bench-Scale Disinfection Of Bacteria And Viruses With Pulsed Arc Electrohydraulic Discharge, L H. Lee, A J. Arnold, C A. Santillan, M B. Emelko, Sarah E. Dickson, J. -S Chang
Bench-Scale Disinfection Of Bacteria And Viruses With Pulsed Arc Electrohydraulic Discharge, L H. Lee, A J. Arnold, C A. Santillan, M B. Emelko, Sarah E. Dickson, J. -S Chang
Sarah E Dickson
Pulsed arc electrohydraulic discharge (PAED) offers concurrent treatment of chemical and microbial target compounds in water by several mechanisms. Here, Escherichia coli, Bacillus subtilis spore, and MS2 bacteriophage inactivation by PAED were investigated using two bench-scale reactors (0.7 and 3 L). A plasma channel was created between a pair of iron electrodes set 0.5 mm apart in these reactors. Pulsed applied voltage was supplied at approximately 0.3 kJ/pulse (~100 ìsec). In the 0.7-L reactor, median E. coli, B. subtilis, and MS2 reductions of 2.4-, 4.6-, and 3.7-log, respectively, were observed after approximately 80 seconds of treatment in water with a …
Expansion Of The Discontinuous Gas Phase And Its Effect On Mass Flux From A Non-Aqueous Phase Liquid (Napl) Pool, Kevin G. Mumford, James E. Smith, Sarah E. Dickson
Expansion Of The Discontinuous Gas Phase And Its Effect On Mass Flux From A Non-Aqueous Phase Liquid (Napl) Pool, Kevin G. Mumford, James E. Smith, Sarah E. Dickson
Sarah E Dickson
The partitioning of non-aqueous phase liquid (NAPL) compounds to a discontinuous gas phase results in the repeated spontaneous expansion, snap-off, and vertical mobilization of the gas phase. This mechanism has the potential to significantly affect the mass transfer processes that control the dissolution of NAPL pools by increasing the vertical transport of NAPL mass and increasing the total mass transfer rate from the surface of the pool. The extent to which this mechanism affects mass transfer from a NAPL pool depends on the rate of expansion and the mass of NAPL compound in the gas phase. This study used well-controlled …
On The Appropriate “Equivalent Aperture” For The Description Of Solute Transport In Single Fractures: Laboratory-Scale Experiments, Qinghuai Zheng, Sarah E. Dickson, Yiping Guo
On The Appropriate “Equivalent Aperture” For The Description Of Solute Transport In Single Fractures: Laboratory-Scale Experiments, Qinghuai Zheng, Sarah E. Dickson, Yiping Guo
Sarah E Dickson
Three distinct definitions of ‘‘equivalent aperture’’ have been used in the literature to describe variable-aperture fractures; however, significant inconsistencies exist in the literature as to which ‘‘equivalent aperture’’ is appropriate for simulating solute transport. In this work, a systematic series of hydraulic and tracer tests was conducted on three laboratory-scale fracture replicas, and the cubic law, mass balance, and frictional loss apertures were calculated. The analytical solution of the one-dimensional advectiondispersion equation was fit to the experimental breakthrough curves. Additionally, one of the experimental aperture fields was measured directly using a light transmission technique. The results clearly demonstrate that the …
Slow Gas Expansion In Saturated Natural Porous Media By Gas Injection And Partitioning With Non-Aqueous Phase Liquids, Kevin G. Mumford, Sarah E. Dickson, James E. Smith
Slow Gas Expansion In Saturated Natural Porous Media By Gas Injection And Partitioning With Non-Aqueous Phase Liquids, Kevin G. Mumford, Sarah E. Dickson, James E. Smith
Sarah E Dickson
The partitioning of volatile non-aqueous phase liquid (NAPL) compounds to a discontinuous gas phase can result in the expansion of that gas phase, and the resulting gas flow can significantly affect the mass transfer from NAPL source zones. This recently reported gas flow generated by the spontaneous expansion of a discontinuous gas phase has not been extensively characterized in the literature. This study measured the expansion rate of a single gas cluster in a 1.1 mm sand above a pool of trans-1,2-dichloroethene (tDCE) in small-scale flow cell experiments. To characterize the gas flow, gas injection experiments in three sizes of …
Spontaneous Expansion And Mobilization Of Gas Above Dnapl, Kevin G. Mumford
Spontaneous Expansion And Mobilization Of Gas Above Dnapl, Kevin G. Mumford
Sarah E Dickson
No abstract provided.
Multivariate Analysis Of Groundwater And Soil Data From A Waste Disposal Site, Kevin G. Mumford, John F. Macgregor, Sarah E. Dickson, Richard H. Frappa
Multivariate Analysis Of Groundwater And Soil Data From A Waste Disposal Site, Kevin G. Mumford, John F. Macgregor, Sarah E. Dickson, Richard H. Frappa
Sarah E Dickson
Environmental site investigations often involve the collection and analysis of hundreds of samples producing data sets that contain thousands of data points, which are difficult and time consuming to analyze. Consequently, investigators often focus on key surrogate parameters for site characterization and remedial action planning and assessment, which results in a large portion of the data collected remaining unused. This study presents the application of principal component analysis (PCA) as an efficient statistical technique to examine large environmental data sets through highlighting patterns in a reduced-variable space. In this work, PCA was applied to ground water and soil data collected …
Removal Of Methyl-Tert Butyl Ether From Water By A Pulsed Arc Electrohydraulic Discharge System, Danielle M. Angeloni, Sarah E. Dickson, Monica B. Emelko, J -S Chang
Removal Of Methyl-Tert Butyl Ether From Water By A Pulsed Arc Electrohydraulic Discharge System, Danielle M. Angeloni, Sarah E. Dickson, Monica B. Emelko, J -S Chang
Sarah E Dickson
The removal of methyl-tert-butyl ether (MTBE) from water by a pulsed arc electrohydraulic discharge (PAED) system was investigated experimentally at the laboratory scale. The effects of arc electrode gap, detention time and initial solution pH on the efficacy of MTBE treatment by PAED were investigated. A 0.3 kJ/pulse spark-gap-type power supply was employed in combination with a 3.0 L flow-through reactor. Experimental results showed that: 1) oxidation reactions are induced by this PAED system; 2) removal efficiency increases with increasing cumulative input energy (kW·h/m3 or kJ/L); 3) removal efficiency decreases with increasing arc electrode gap; and 4) initial solution pH …
Pulsed Electrohydraulic Discharge Characteristics In An Eccentric Electrode Cylindrical Reactor With Pbs, A Yamataki, D M. Angeloni, Sarah E. Dickson, Monica B. Emelko, K Yasuoka, J -S Chang
Pulsed Electrohydraulic Discharge Characteristics In An Eccentric Electrode Cylindrical Reactor With Pbs, A Yamataki, D M. Angeloni, Sarah E. Dickson, Monica B. Emelko, K Yasuoka, J -S Chang
Sarah E Dickson
Pulsed arc electrohydroulic discharge (PAED) has been proposed as a water treatment technology for the removal of chemical and microbial contaminants. In this work, we examined the fundamental characteristics of a PAED system with an eccentric electrode cylindrical reactor. Phosphate-buffered saline (PBS) water was used in lieu of tap water, because the conductivity of PBS is much higher than that of tap water. The results show that the voltage and current waveforms generated in PBS and tap water are very different due to the higher conductivity of PBS. Strong pressure waves and UV emission were also observed in PBS.
Decision Support System For Rural Water Supply In The Nilgris District Of South India, Daniel Olsen, Sarah E. Dickson, Brian Baetz
Decision Support System For Rural Water Supply In The Nilgris District Of South India, Daniel Olsen, Sarah E. Dickson, Brian Baetz
Sarah E Dickson
A considerable amount of knowledge exists for planning, designing, and implementing rural water supply schemes in developing countries around the world. Generalized decision support systems (DSSs) are used to tackle the daunting task of providing water in areas that have poor water resources and limited financial capacity. However, there is a lack of site-specific DSSs that utilise local hydrological and socio-economic data for assessing regionally-based rural water supply schemes. In the Nilgiris District of South India, an organizational structure exists for improving local water resources through watershed management projects, but many of the tools used to make informed decisions are …
A Novel Amendment Delivery System, Erica Ryter
Dissolution Of Entrapped Dnapls In Variable Aperture Fractures: Experimental Data And Empirical Model, Sarah E. Dickson, Neil R. Thomson
Dissolution Of Entrapped Dnapls In Variable Aperture Fractures: Experimental Data And Empirical Model, Sarah E. Dickson, Neil R. Thomson
Sarah E Dickson
An appreciation of the dissolution from entrapped nonaqueous phase liquids (NAPLs) in fractures is essential as we attempt to understand and predict the fate of NAPLs present in fractured rock systems. Eight long-term dissolution experiments using 1,1,1-trichloroethane and trichloroethylene were conducted in two laboratory-scale dolomitic limestone variable aperture fractures under various conditions. Between 560 and 2600 fracture volumes of water were passed through the fractures resulting in the removal of 10−60% of the initial mass trapped. The effluent concentration profiles revealed three distinct and characteristic stages of dissolution: an initial pseudosteady stage, a transient stage, and a tailing stage. On …
The Dissolution Of Dnapls In Variable Aperture Fractures, Sarah E. Dickson
The Dissolution Of Dnapls In Variable Aperture Fractures, Sarah E. Dickson
Sarah E Dickson
No abstract provided.