Ad Hoc networks are multi-hop wireless networks consisting of mobile hosts. They do not have any pre-existing network infrastructure and are characterized by constantly changing topology, limited battery power and bandwidth. Typical applications of such networks are battlefield networks, medical relief during natural calamities or disasters, conference room networking, and...
This study investigated the use of radon-222 as an in situ partitioning tracer for quantifying nonaqueous phase liquid (NAPL) saturations in the subsurface. Laboratory physical aquifer models (PAMs), field experiments, and numerical simulations were used to investigate radon partitioning in static (no-flow) experiments and in single-well, 'push-pull' tests conducted in...
An experimental and numerical modeling investigation was conducted to study interactions between microbial dynamics and transport processes in variably saturated porous media. These interactions are important in a variety of applied problems such as water and wastewater treatment, bioremediation, and oil-field recovery operations. These processes and interactions also have great...
My research has focused on understanding N and C cycling in soils at small scales. Isotope dilution methods commonly used to estimate gross rates of soil chemical transformations assume homogeneous distribution of label. I explored the effects of diffusion limitations on isotope dilution experiments in soil aggregates using spherical diffusion-reaction...
In an effort to restore summer flows in the Walla Walla River to provide passage
and habitat for ESA (endangered species act) listed bull and steelhead trout irrigation
districts left 13 cubic-feet-per-second (c.f.s) (0.37 m ³/s) in the main channel during
irrigation season (May-November) for the first time in over...
I examined hydrological and plant community changes associated with the implementation of a restoration management plan in two riparian meadows located within an agricultural landscape of the central Willamette Valley, Oregon. I established exclosure fencing (a form of passive restoration) in one agricultural field and established fencing and plugged a...
The City of Woodburn, Oregon's Wastewater Treatment Plant (WWTP) has been investigating several natural alternatives for improving effluent quality. Based on its current National Pollution Discharge Elimination System (NPDES) permit, the WWTP will require additional reduction of temperature and ammonia levels in the summer, especially in the critical month of...
Fine particles and colloids, attached to grain surfaces, are abundant in the earth's subsurface. Under certain conditions these particles can be released from the matrix and transported with the mobile phase. One of the mechanisms for sudden particle release is a decrease in groundwater salt concentration below the critical salt...
A relatively stable, persistent and historical problem with elevated NO₃⁻ concentrations in rural drinking wells in the southern Willamette Valley, Oregon is evident. What is the origin of NO₃⁻ in rural drinking water wells in this area? The answer to the question is not simple. Many non-point sources contribute to...
A zeolite packed biofilter was retrofitted to a confined swine feeding operation in Eastern Washington, and evaluated for its ability to reduce the malodors from fan exhaust drawn from an internal under-slat manure storage pit. Ammonia (NH₃) was used as the representative constituent of swine waste malodor due to its...
This research analyzes the effects of islands on river process and the effects river processes have on island formation. A fluvial island is defined herein as a land mass within a river channel that is separated from the floodplain by water on all sides, exhibits some stability, and remains exposed...
A study was conducted to investigate the influence of root reinforcements on soil strength and the initiation of static liquefaction in forest soils. The design and operation was developed of an apparatus capable of modeling rainfall-induced shallow hill-slope failures that also permitted observation of the soil volume change tendencies at...
The age, or residence time of water is a fundamental descriptor of catchment hydrology, revealing information about the storage, flow pathways and source of water in a single integrated measure. While there has been tremendous recent interest in residence time to characterize catchments, there are few studies that quantify residence...
This investigation explored how the magnitude, style, and frequency of
channel adjustments vary spatially and over time within a 5th-order mountain
watershed. Historical data sets, including repeated cross section surveys spanning up
to 20 years at five sites on 2nd to 5th-order channels and streamflow records spanning
up to 50...
Recent advances in imaging technology and numerical modeling have greatly enhanced pore-scale investigations of multiphase flow and transport in porous media. It is now feasible to obtain high resolution 3-dimensional pore-scale data, and numerical methods such as the lattice-
Boltzmann (LB) technique have been developed specifically for simulating such phenomena....
In this thesis, we investigate the problem of simulating Maxwell's equations in dispersive dielectric media. We begin by explaining the relevance of Maxwell's equations to
21st century problems. We also discuss the previous work on the numerical simulations of
Maxwell's equations. Introductions to Maxwell's equations and the Yee finite difference...
Simulations of stream-subsurface water exchange (hyporheic exchange) using a three-dimensional steady state groundwater flow model and a particle tracking model in unconstrained and constrained reaches of small (2nd-order) and intermediate (5th-order) mountain streams were conducted to estimate the effects of geomorphic features on the extent, volume and residence time of...
Oregon State University has recently conducted a complete core conversion analysis as part of the Reduced Enrichment for Research and Test Reactors Pprogram. The goals of the thermal hydraulic analyses were to calculate natural circulation flow rates, coolant temperatures and fuel temperatures as a function of core power for both...
The Willamette Silt is a surficial geologic unit composed of successive Missoula Flood Deposits that underlies 3100 km2 (1200 mil) of arable land in the Willamette Valley of Oregon. The Willamette Silt protects the underlying regionally important Willamette
Aquifer from agricultural contamination while acting as a semi-confining unit and a...
The basaltic landscapes of the Oregon High Cascades form a natural laboratory for examining how geologic setting and history influence groundwater flowpaths, streamflow sensitivity to climate, and landscape evolution. In the High Cascades, highly permeable young basaltic lavas form extensive aquifers. These aquifers are the dominant sources of summer streamflow...
With 97% of the world’s freshwater resources stored underground, the connection between groundwater resources to the metrics of space, scale and time common to the geographic study of natural resources has not been extensively investigated by geographers. While nearly 240 transboundary aquifers are mapped across the world, a potential “tragedy”...
Three approaches toward the core of halichlorine and pinnaic acid are described. The first approach entails a racemic transannular nitrone-olefin [3+2] cycloaddition from nitrone 238. Construction of the nitrone 238 began with aldehyde 241. Another key feature in this route involved a ring-closing metathesis for the formation of a 14-membered...
Dam removal is increasingly viewed as a river restoration tool because dams affect so many aspects of river hydrology, geomorphology, and ecology; but removal also has impacts. When a dam is removed, sediment accumulated over a dam’s lifetime may be transported downstream; and the timing, fate and consequences of this...
This dissertation concentrates on the controlling factors on the instability of the Laurentide Ice Sheet (LIS) and their effects on abrupt climate change. Northern Hemisphere climate fluctuated abruptly during the last deglaciation possibly related to variability in Atlantic meridional overturning circulation (AMOC) and reduced aerial extent of the LIS. Reductions...