Understanding the transport of three fluid phases through porous media has important applications in subsurface contaminant remediation, oil and gas recovery, and geological CO₂ sequestration. Existing transport models may be improved by including physical phenomena that govern fluid flow at the pore scale. In particular, thermodynamic arguments suggest that hysteresis...
This research examines the independent and combined effects of drainage and imbibition flowrate on nonwetting phase capillary trapping in a two-phase, porous medium system. A uniform system of cubic arrangement and non-uniform systems of both cubic and rhombohedral arrangements were examined in order to analyze and compare the nonwetting phase...
Multi-phase flow in porous media includes many instances of subsurface flow. Three-phase flow in particular is important in situations of enhanced oil recovery, CO2 sequestration, and groundwater remediation. Many studies have been performed on how two fluid phases (oil/water or air/water) behave in porous media, but very few studies exist...
Systems that contain multi-phase flow in porous media are of interest in diverse fields including environmental engineering, hydrogeology, and petroleum engineering etc. One of the main descriptors of multi-phase flow in porous media is the relationship between capillary pressure and fluid saturation. Capillary pressure is inherently a pore-scale variable and...
This work examines the impact of a viscosity force parameter, fluid velocity, and a capillary force parameter, interfacial tension, on the saturation, morphology, and topology of NW fluid in Bentheimer sandstone after primary imbibition, drainage, and secondary imbibition. Brine and air (used as a proxy for supercritical CO₂) flow experiments...
The wetting of a surface by a liquid is a crucial part of many natural and industrial processes. Despite numerous existing studies, some elements of wetting-dewetting such as contact angle variation are still poorly understood. Knowledge of contact angle behavior during the flow is necessary for modeling fluid displacements in...
Engineered capillary barriers typically consist of two layers of granular materials designed so that the contrast in sediment hydrologic properties and sloping interface retains infiltrating water in the upper layer. We report here on the results of two bench-top capillary barrier experiments, and associated modeling. These experiments were conducted to...
Understanding the mechanisms controlling colloid transport and deposition in the vadose zone is an important step in protecting our water resources. Colloid transport in unsaturated porous media was studied using X-Ray Microtomography (XMT), which is a non-destructive imaging technique that provides three-dimensional images at a resolution on the order of...
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Dorthe Wildenschild
Understanding the mechanisms controlling colloid transport and
Atmospheric carbon reduction is arguably the most crucial facet among efforts to mitigate climate change. The Fifth International Panel of Climate Change report emphasizes a worldwide goal of maintaining global temperature elevation less than 1.5°C above pre-industrial temperatures. This report also acknowledges without the proper utilization of counteractive emission strategies...
Geological carbon sequestration, as a method of atmospheric greenhouse gas reduction, is at the technological forefront of the climate change movement. During sequestration, carbon dioxide (CO₂) gas effluent is captured from coal fired power plants and is injected into a storage saline aquifer or depleted oil reservoir. In an effort...
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Dorthe Wildenschild
Geological carbon sequestration, as a method of atmospheric greenhouse
Use of basalt aquifers for aquifer storage and recovery (ASR) systems is increasing in the Pacific Northwest due to the large aerial extent of the Columbia River Basalt Group and the suitability of basalts as ASR reservoirs. However, the degradation of trihalomethanes (THMs), potentially carcinogenic disinfection by-products present in the...
Heterogeneous porous material represents a persistent challenge in the field of engineering. Microscale properties such as the porosity and microchannel torturosity significantly control the macroscale transport characteristics of homogeneous porous medium. Additional complexity is introduced when these small-scale features vary in space. Examples of heterogeneous porous systems include artificial body...
The objective of this study is to investigate the dispersion of solute matter introduced into a fully developed laminar flow in a circular capillary tube under preasymptotic regimes. For this purpose, we have used the method of volume averaging to upscale microscale balance equations for the case of diffusion-convection transport...
This work is an attempt to develop a simple physical description for the initial
interactions between a bacterial cell and a substrate surface. This is done by
adopting a view that regards bacterial surface biomolecules not as secondary and
add-on contributors to the potential energy function that characterizes the
overall...
Elevated groundwater nitrate (NO3
-) concentrations in the Southern Willamette
Valley (SWV) caused the Oregon Department of Environmental Quality (ODEQ) to
declare a Groundwater Management Area (GWMA) in Spring, 2004. To better
understand direction of groundwater flow, groundwater age, and nitrate transport
pathways of the SWV we developed a steady-state...
This work focuses on solute mass transport in a highly heterogeneous two-region porous medium consisting of spherical low-hydraulic conductivity inclusions, embedded in a high-hydraulic conductivity matrix. The transport processes occuring in the system are described by three distinct time scales. The first time scale reflects the characteristic time for convective...
Low-permeability geologic units may offer significant chemical and hydraulic protection of adjacent aquifers, and are important for managing groundwater quality, especially in areas with significant non-point source contamination. Nitrate in the Willamette Valley is attenuated across the Willamette Silt, a semi-confining unit overlying a regionally important aquifer. To quantify the...
Groundwater nitrate contamination is a well-documented issue in the Southern Willamette Valley (SWV) of Oregon, as a Groundwater Management Area (GWMA) has recently been declared. As a GWMA, groundwater nitrate monitoring must occur until regional concentrations are below 7 mg/L NO3-N. However, the presence of temporal variability can make it...
In order to better predict the aggregation state of nanomaterials, the factors that influence aggregation must be understood. The combined effects of natural and engineered coatings have been shown to factor into nanoparticle aggregation behavior in preliminary research. In this study, aggregation behaviors of gold nanoparticles with two different engineered...
Abstract Watershed-scale fate/transport modeling of contaminants is a tool that scientists and land managers can use to assess pesticide contamination to stream systems. The Catchment Modeling Framework (CMF) is a catchment-scale fate/transport modeling tool. It was developed to help scientists and land managers assess the effects of possible land-use decisions...
Microplastics, plastic marine debris less than 5 mm in size, is a threat to the health of our oceans. One important way to reduce microplastics in our oceans is to educate people about the issue, particularly future decision-makers. In this study, a middle school curriculum was developed using current scientific...
This thesis presents an experimental study of radial porosity in a manually filled cylindrical container with glass spheres. The symmetric distribution of bead diameter allowed for normalization of container properties and porosity models. The aspect ratio of the container was approximately 3.9, with tube-to-particle-diameter ratio λ ≈ 24.6 and height-to-particle-diameter...
Interest in performance specifications has been growing in the civil and construction industry in the past decade. One major focus area has been on understanding how to prolong the service life of concrete structures, since repair and rehabilitation of existing infrastructure have cost many trillions of dollars. Deterioration mechanisms such...
Few studies have examined both long-term and fine-scale spatial variations in
water quality of small streams in the Pacific Northwest. As such, a case study was
conducted to determine if current physical and chemical properties of water in three
streams located in the Oregon Coast Range differed from historically measured...
Soils have a critical role in global carbon (C) cycling, containing one of the largest fast-cycling carbon stocks on earth. Robust representation of soil organic matter dynamics in Earth System Models is critical for future climate prediction. Current C cycling models assume that all C cycling in non-hydric (i.e. ‘upland’)...
Remote sensing techniques have been applied extensively in geospatial investigations, but their use in measuring soil physical attributes has been far less explored. Soil particle size distributions (PSD) are indispensable in modeling pedological and hydrological processes as well as biodiversity. However, estimation of PSD via gravimetric measurement methods, the standard...
Moisture durability is essential for wood composites, especially those used in building construction, where products are prone to weathering. The primary focus of this research was to determine if adhesive penetration into the cell wall has a positive influence on adhesive bond durability. To fully understand the measureable effects of...
The shallow aquifer in Southern Willamette Valley (SWV) has high levels of nitrate, and we are exploring the time trends in nitrate, and the hydrologic and land management factors that contribute to this problem. Nitrogen (N) inputs to farmland from fertilizer is thought to be the primary source of nitrogen...
Evaporation synergy is the phenomenon in which two porous medium textures that share a common vertical boundary experience a higher cumulative evaporation than either homogeneous texture can produce. Studies that have been conducted to date address this phenomenon in relatively fine and coarse sands but not in finer textured soils...
An ASR metric and site rating index applied to over 120 municipal and agricultural locations across Oregon, combined with comparison to case study data from existing ASR sites, indicate that more than 50% of selected sites are hydrogeologically suitable for ASR. The ASR metric is a ratio of aquifer storage...