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2011

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Articles 10051 - 10080 of 10326

Full-Text Articles in Physical Sciences and Mathematics

Gold(I)-Catalyzed Rearrangements Of Allyl Aryl Ethers: Mechanisitc And Synthetic Studies, Heidi E. Dimmitt Jan 2011

Gold(I)-Catalyzed Rearrangements Of Allyl Aryl Ethers: Mechanisitc And Synthetic Studies, Heidi E. Dimmitt

WWU Graduate School Collection

Gold catalyzed reactions are an active area of interest for synthetic chemists due to gold's ability to promote formation of carbon-carbon bonds. A mechanistic study of the aromatic Claisen rearrangement of allyl aryl ethers in the presence of a gold catalyst has shed some light on the role of the gold catalyst in this reaction. Studies probing the electronics requirements of the reaction as well as investigation of stereochemical conservation both support a dissociative ionic mechanism. Our data supports that the catalyst interacts primarily with the alkene branch as opposed to the phenoxide oxygen because the E and Z allyl …

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Groundwater Response To Precipitation Events, Kalaloch, Olympic Peninsula, Washington, Casey R. Hanell Jan 2011

Groundwater Response To Precipitation Events, Kalaloch, Olympic Peninsula, Washington, Casey R. Hanell

WWU Graduate School Collection

Tens of thousands of square kilometers of forestland in Washington are managed as working forests, primarily for timber production. The effects of timber harvesting on physical watershed processes continue to be the subject of intense research throughout the Pacific Northwest. Watershed analyses completed in Washington during the mid-1990s resulted in significant modifications to Washington's Forest Practices Act and Rules. These measures mandate rigorous evaluation of potential effects of timber harvesting on slope stability. Although timber harvesting has been linked to an increase in surface erosion and mass wasting in the Pacific Northwest, most studies have focused on shallow landslide processes. …

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Holocene Glaciation Of The Green River Drainage, Wind River Range, Wyoming, Nigel Davies Jan 2011

Holocene Glaciation Of The Green River Drainage, Wind River Range, Wyoming, Nigel Davies

WWU Graduate School Collection

The Wind River Range (WRR) has long been the focus of glacial investigations, yet the Holocene record remains poorly understood. Moraines in the Green River Lakes drainage, on the northwest end of the Wind River Range, preserve a remarkably complete moraine record of late-Pleistocene recession, late-glacial and late-Holocene advances. At last glacial maximum (LGM) the study area supported large valley glaciers that extended beyond the rangefront; in historic times, however, glaciers are restricted to high alpine cirques. The largest remaining active glacier (Mammoth Glacier) has retreated to 2 km2 and is the primary source of meltwater and outwash to the …

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The First Pre- And Post-Wildfire Charcoal Quantification Using Peroxide-Acid Digestion, Melissa R.A. Pingree Jan 2011

The First Pre- And Post-Wildfire Charcoal Quantification Using Peroxide-Acid Digestion, Melissa R.A. Pingree

WWU Graduate School Collection

In the summer of 2002, the 200,000-ha Biscuit Wildfire consumed a portion of the 150-ha Long-Term Ecosystem Productivity (LTEP) experiment in the Siskiyou National Forest, Oregon. The wildfire burned previously established 100-year-old conifer control and thinned experimental units, which allows comparison with prescribed burn and unburned units. This research evaluates the O horizon and mineral soil charcoal, a key fire-related soil component that affects physical and chemical properties. Charcoal C was quantified by a peroxide-acid digestion method developed for forest soils. Charcoal C was 17% of the organic C for a reference Australian Vertisol soil and 9% for a German …

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Derivation Of The Eruption History Of The Prehistoric Ring Creek Lava Flow, Southern British Columbia, Samuel Bruno Jan 2011

Derivation Of The Eruption History Of The Prehistoric Ring Creek Lava Flow, Southern British Columbia, Samuel Bruno

WWU Graduate School Collection

The Ring Creek lava flow is a 10,000 year old, post-glacial dacitic lava flow that originated from Opal Cone, a small cinder cone on the south east flank of Mt. Garibaldi, British Columbia. Disequilibrium texture of amphibole combined with clotting in plagioclase suggests that the Ring Creek magma stalled beneath Opal Cone for at least 440 days before the eruption of the Ring Creek lava flow. Use of an igneous plagioclaseliquid thermo barometer and hygrometer indicate shallow storage conditions of 818 - 868o C, 2.4 - 3.6 kbar, and 0.2 - 2.0 wt% H2O. Surge in plagioclase growth, evidenced by …

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Controlled Growth Of Organic Semiconductor Films In Liquid, Daniel W. (Daniel Wainwright) Shaw Jan 2011

Controlled Growth Of Organic Semiconductor Films In Liquid, Daniel W. (Daniel Wainwright) Shaw

WWU Graduate School Collection

Organic molecular crystalline (OMC) films are being investigated for use in a wide range of potential applications, from field effect transistors, to light-emitting diodes, and photovoltaic cells. The ultimate utility of OMC materials for such applications will depend on the degree and type of molecular order in deposited films, as well as the processing costs for preparing them. The goal of this thesis is to develop a method to produce high quality OMC thin films under ambient conditions, to characterize those films, and their growth kinetics. In particular, I will investigate OMC film growth by ambient axisymmetric spray method, a …

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Soils As A Source Of Bioavailable Phosphorus In The Lake Whatcom Watershed, Scott Groce Jan 2011

Soils As A Source Of Bioavailable Phosphorus In The Lake Whatcom Watershed, Scott Groce

WWU Graduate School Collection

Lake Whatcom is a warm monomictic lake located east of the City of Bellingham, WA, U.S.A. and serves as the primary drinking water source for approximately 100,000 Whatcom County and City of Bellingham residents. Matthews et al. (2004) noted indicators of increasing algal productivity in the lake. My study quantified the amount of soluble, bioavailable, and total phosphorus in the Lake Whatcom watershed soils to help quantify the major sources of phosphorus entering the lake. In addition, I assessed the influence of soil factors (soil series, size fraction, aspect, elevation, pH, slope, percent organic matter, median particle size, and percent …

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The Effects Of Symbiotic State On Heterotrophic Feeding In The Temperate Anemone Anthopleura Elegantissima, Terra C. (Terra Celeste) Hiebert Jan 2011

The Effects Of Symbiotic State On Heterotrophic Feeding In The Temperate Anemone Anthopleura Elegantissima, Terra C. (Terra Celeste) Hiebert

WWU Graduate School Collection

The temperate sea anemone, Anthopleura elegantissima is facultatively symbiotic with at least two distinct algae: zooxanthellae (Symbiodinium muscatinei) and zoochlorellae (Elliptochloris marina). Symbiotic A. elegantissima potentially receive excess photosynthate from their algal partners, which supplements heterotrophic feeding. But asymbiotic individuals must rely solely on heterotrophic food sources. We predicted that asymbiotic A. elegantissima, due to their lack of algal symbionts, would have a more effective heterotrophic feeding strategy. Symbiotic and asymbiotic A. elegantissima were collected from the field and heterotrophic feeding features were measured (i.e., anemone morphology, tentacle adhesive force, nematocyte sensitivity, cnida size, cnida density, ingestion time, digestion time …

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Oriented Fluorophore Luminescent Solar Concentrators, Christopher J. (Christopher John) Westcott Jan 2011

Oriented Fluorophore Luminescent Solar Concentrators, Christopher J. (Christopher John) Westcott

WWU Graduate School Collection

Though the sun's energy is the world's most prominent renewable energy resource, technologies such as photovoltaics (PVs) have yet to become a significant factor in the energy market due in part to the sheer cost of unit deployment. Luminescent Solar Concentrators (LSCs) have been investigated since the late 1960s as a means of reducing the cost of PV arrays by replacing large areas of expensive PVs with cheaper materials such as glass or plastic. LSCs function by using fluorescent dyes embedded in a host matrix that absorb the sun's rays and redirects the light through total internal reflection to small …

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Sub-Vertical Fluid Flow During Prograde Metamorphism In The Nason Terrane, North Cascades Crystalline Core, Washington, Perry M. (Perry Martin) Ponshock Jan 2011

Sub-Vertical Fluid Flow During Prograde Metamorphism In The Nason Terrane, North Cascades Crystalline Core, Washington, Perry M. (Perry Martin) Ponshock

WWU Graduate School Collection

The nature of fluid movement through the lower crust during prograde metamorphism is an important but poorly understood part of the global H2O and CO2 cycles on this planet. A broad set of samples from some of the structurally deepest exposures of the Nason terrane in the Cascades crystalline core were used to evaluate fluid movement during peak amphibolite-grade metamorphism. XRF bulk-rock chemical analyses, T-X(CO2) pseudosections, and thin-section petrography were used to identify equilibrium fluid composition for the solid phases in each specimen; these span the gamut of X(CO2) values. The juxtaposition of gneiss and marble-lithologies with differing equilibrium fluid …

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Hydrologic And Geomorphic Assessment Of Ebey's Prairie, Central Whidbey Island, Washington, Michael A. (Michael Allen) Larrabee Jan 2011

Hydrologic And Geomorphic Assessment Of Ebey's Prairie, Central Whidbey Island, Washington, Michael A. (Michael Allen) Larrabee

WWU Graduate School Collection

Ebey's Prairie, Washington, was once bisected by a broad riparian corridor consisting of waterlogged soils, swampy areas, seasonal ponds, and intermittent flows, which helped recharge the local aquifer. By the mid-1900s, agriculture drainage tiles, drainage ditches, and fill were being installed by landowners to increase tillable acreage. The extent and location of these drainage tiles or the effects these tiles have had on surface water and subsequently on aquifer recharge in the area remains uncertain. In this study, I characterized the modern and historic surface hydrologic conditions of Ebey's Prairie and their relationship to the local geomorphology. I used the …

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Sea Level Rise And Sediment Elevation Dynamics In A Hydrologically Altered Puget Sound Estuary, Kara D. Kuhlman Jan 2011

Sea Level Rise And Sediment Elevation Dynamics In A Hydrologically Altered Puget Sound Estuary, Kara D. Kuhlman

WWU Graduate School Collection

As sea level rise (SLR) accelerates in response to climate change, coastal wetlands must accrete vertically to prevent submergence and habitat loss. Padilla Bay, an estuary in the Puget Sound containing an expansive eelgrass meadow, has been hydrologically altered such that insufficient sedimentation may now prevent vertical accretion, potentially affecting the long-term survival of the eelgrass meadow. The objective of this study was to quantify trends in surface elevation change throughout Padilla Bay. To this end, our research group monitored surface elevation change at 19 sites from 2002-2010 using sediment elevation tables (SET's). Additionally, I explored potential ecogeomorphic relationships between …

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The Influence Of Humic Acid And Water Hardness On The Partitioning Of Silver Ions And Nanoparticles Between Fresh Water And Freshwater Algae, Matthew D. Ferguson Jan 2011

The Influence Of Humic Acid And Water Hardness On The Partitioning Of Silver Ions And Nanoparticles Between Fresh Water And Freshwater Algae, Matthew D. Ferguson

WWU Graduate School Collection

Silver nanoparticle (AgNP) containing products are abundant in consumer goods. If trends continue, AgNP levels will continue to rise as innovative applications continue to be realized. These nanoparticles (NPs) can enter the environment as their uses can transport them to natural waters (e.g., washing socks containing AgNPs). Research on the behavior of AgNPs and Ag+ in artificial fresh water is presented in this thesis. Specifically, their sorptive properties between fresh water and freshwater algae, Pseudokirchneriella subcapitata (Korshikov) Hindák, as a function of hardness, humic acid (HA) content, and silver type were investigated. The experimental design was modeled after a 23 …

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Evaluating The Contribution To Toxicity Of Weak Black Liquor In Pulp Mill Effluents, Renee L. Ragsdale Jan 2011

Evaluating The Contribution To Toxicity Of Weak Black Liquor In Pulp Mill Effluents, Renee L. Ragsdale

WWU Graduate School Collection

Weak black liquor (WBL) losses in pulp mills may affect effluent treatment efficiencies and may be linked to aquatic toxicity observed in final mill effluents. Best management practices (BMP) for controlling losses of WBL have been effective at reducing WBL from entering the mill effluent treatment system, but it is unclear at what level WBL may contribute to increased toxicity, or whether specific chemical compounds found in WBL may be consistently responsible. The objective of this study was to evaluate the contribution of WBL in biologically-treated bleached kraft pulp mill effluents to toxicity, and to assess effluent chemical parameters that …

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Characterizations Of Exponential Distribution Via Conditional Expectations Of Record Values, George Yanev Jan 2011

Characterizations Of Exponential Distribution Via Conditional Expectations Of Record Values, George Yanev

School of Mathematical and Statistical Sciences Faculty Publications and Presentations

We prove that the exponential distribution is the only one which satisfies a regression identity. This identity involves conditional expectation of the sample mean of record values given two record values outside of the sample.

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Acceleration Techniques By Post-Processing Of Numerical Solutions Of The Hammerstein Equation, Khomsan Neamprem, Hideaki Kaneko Jan 2011

Acceleration Techniques By Post-Processing Of Numerical Solutions Of The Hammerstein Equation, Khomsan Neamprem, Hideaki Kaneko

Mathematics & Statistics Faculty Publications

No abstract provided.

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Numerics Of The Lattice Boltzmann Method: Effects Of Collision Models On The Lattice Boltzmann Simulations, Li-Shi Luo, Wei Liao, Xingwang Chen, Yan Peng, Wei Zhang Jan 2011

Numerics Of The Lattice Boltzmann Method: Effects Of Collision Models On The Lattice Boltzmann Simulations, Li-Shi Luo, Wei Liao, Xingwang Chen, Yan Peng, Wei Zhang

Mathematics & Statistics Faculty Publications

We conduct a comparative study to evaluate several lattice Boltzmann (LB) models for solving the near incompressible Navier-Stokes equations, including the lattice Boltzmann equation with the multiple-relaxation-time (MRT), the two-relaxation-time (TRT), the single-relaxation-time (SRT) collision models, and the entropic lattice Boltzmann equation (ELBE). The lid-driven square cavity flow in two dimensions is used as a benchmark test. Our results demonstrate that the ELBE does not improve the numerical stability of the SRT or the lattice Bhatnagar-Gross-Krook (LBGK) model. Our results also show that the MRT and TRT LB models are superior to the ELBE and LBGK models in terms of …

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Mesoscopic Methods In Engineering And Science, Chuguang Zheng, Jiding Lu, Zhaoli Guo, Li-Shi Luo, Manfred Krafczyk Jan 2011

Mesoscopic Methods In Engineering And Science, Chuguang Zheng, Jiding Lu, Zhaoli Guo, Li-Shi Luo, Manfred Krafczyk

Mathematics & Statistics Faculty Publications

Matter, conceptually classified into fluids and solids, can be completely described by the microscopic physics of its constituent atoms or molecules. However, for most engineering applications a macroscopic or continuum description has usually been sufficient, because of the large disparity between the spatial and temporal scales relevant to these applications and the scales of the underlying molecular dynamics. In this case, the microscopic physics merely determines material properties such as the viscosity of a fluid or the elastic constants of a solid. These material properties cannot be derived within the macroscopic framework, but the qualitative nature of the macroscopic dynamics …

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Imbalanced Learning For Functional State Assessment, Feng Li, Frederick Mckenzie, Jiang Li, Guanfan Zhang, Roger Xu, Carl Richey, Tom Schnell, Thomas E. Pinelli (Ed.) Jan 2011

Imbalanced Learning For Functional State Assessment, Feng Li, Frederick Mckenzie, Jiang Li, Guanfan Zhang, Roger Xu, Carl Richey, Tom Schnell, Thomas E. Pinelli (Ed.)

Electrical & Computer Engineering Faculty Publications

This paper presents results of several imbalanced learning techniques applied to operator functional state assessment where the data is highly imbalanced, i.e., some function states (majority classes) have much more training samples than other states (minority classes). Conventional machine learning techniques usually tend to classify all data samples into majority classis and perform poorly for minority classes. In this study, we implemented five imbalanced learning techniques, including random under-sampling, random over-sampling, synthetic minority over-sampling technique (SMOTE), borderline-SMOTE and adaptive synthetic sampling (ADASYN) to solve this problem. Experimental results on a benchmark driving test dataset show that accuracies for minority classes …

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Automatic Detection Of Aircraft Emergency Landing Sites, Yu-Fei Shen, Zia-Ur Rahman, Dean Krusienski, Jiang Li, Zia-Ur Rahman (Ed.), Stephen E. Reichenbach (Ed.), Mark Allen Neifeld (Ed.) Jan 2011

Automatic Detection Of Aircraft Emergency Landing Sites, Yu-Fei Shen, Zia-Ur Rahman, Dean Krusienski, Jiang Li, Zia-Ur Rahman (Ed.), Stephen E. Reichenbach (Ed.), Mark Allen Neifeld (Ed.)

Electrical & Computer Engineering Faculty Publications

An automatic landing site detection algorithm is proposed for aircraft emergency landing. Emergency landing is an unplanned event in response to emergency situations. If, as is unfortunately usually the case, there is no airstrip or airfield that can be reached by the un-powered aircraft, a crash landing or ditching has to be carried out. Identifying a safe landing site is critical to the survival of passengers and crew. Conventionally, the pilot chooses the landing site visually by looking at the terrain through the cockpit. The success of this vital decision greatly depends on the external environmental factors that can impair …

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2d Face Database Diversification Based On 3d Face Modeling, Qun Wang, Jiang Li, Vijayan K. Asari, Mohammad A. Karim, Manuel Filipe Costa (Ed.) Jan 2011

2d Face Database Diversification Based On 3d Face Modeling, Qun Wang, Jiang Li, Vijayan K. Asari, Mohammad A. Karim, Manuel Filipe Costa (Ed.)

Electrical & Computer Engineering Faculty Publications

Pose and illumination are identified as major problems in 2D face recognition (FR). It has been theoretically proven that the more diversified instances in the training phase, the more accurate and adaptable the FR system appears to be. Based on this common awareness, researchers have developed a large number of photographic face databases to meet the demand for data training purposes. In this paper, we propose a novel scheme for 2D face database diversification based on 3D face modeling and computer graphics techniques, which supplies augmented variances of pose and illumination. Based on the existing samples from identical individuals of …

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Anisotropic Response Of Nanosized Bismuth Films Upon Femtosecond Laser Excitation Monitored By Ultrafast Electron Diffraction, Ahmed R. Esmail, Hani E. Elsayed-Ali Jan 2011

Anisotropic Response Of Nanosized Bismuth Films Upon Femtosecond Laser Excitation Monitored By Ultrafast Electron Diffraction, Ahmed R. Esmail, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

The lattice response of 5 nm thick bismuth film to femtosecond laser excitation is probed by ultrafast electron diffraction. The transient decay time after laser excitation is greater for diffraction from (012) lattice planes compared to (110) planes and is reduced for both planes with the increased laser fluence. These results indicate that different energy coupling mechanisms to the lattice occur depending on the crystal direction. The behavior of the diffraction peak width indicates partial disorder of the film upon photoexcitation that increases together with the laser fluence. © 2011 American Institute of Physics. [doi:10.1063/1.3652919]

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Precise Control Of Highly Ordered Arrays Of Nested Semiconductor/Metal Nanotubes, Diefeng Gu, Helmut Baumgart, Kandabara Tapily, Pragya Shrestha, Gon Namkoong, Xianyu Ao, Frank Müller Jan 2011

Precise Control Of Highly Ordered Arrays Of Nested Semiconductor/Metal Nanotubes, Diefeng Gu, Helmut Baumgart, Kandabara Tapily, Pragya Shrestha, Gon Namkoong, Xianyu Ao, Frank Müller

Electrical & Computer Engineering Faculty Publications

Lithographically defined microporous templates in conjunction with the atomic layer deposition (ALD) technique enable remarkable control of complex novel nested nanotube structures. So far three-dimensional control of physical process parameters has not been fully realized with high precision resolution, and requires optimization in order to achieve a wider range of potential applications. Furthermore, the combination of composite insulating oxide layers alternating with semiconducting layers and metals can provide various types of novel applications and eventually provide unique and advanced levels of multifunctional nanoscale devices. Semiconducting TiO2 nanotubes have potential applications in photovoltaic devices. The combination of nanostructured semiconducting materials …

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Nonuniformity In Lattice Contraction Of Bismuth Nanoclusters Heated Near Its Melting Point, A. Esmail, M. Abdel-Fattah, Hani E. Elsayed-Ali Jan 2011

Nonuniformity In Lattice Contraction Of Bismuth Nanoclusters Heated Near Its Melting Point, A. Esmail, M. Abdel-Fattah, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

The structural properties of bismuth nanoclusters were investigated with transmission high-energy electron diffraction from room temperature up to 525 ± 6 K. The Bi nanoclusters were fabricated by thermal evaporation at room temperature on transmission electron microscope grids coated with an ultrathin carbon film, followed by thermal and femtosecond laser annealing. The annealed sample had an average cluster size of ∼14 nm along the minor axis and ∼16 nm along the major axis. The Debye temperature of the annealed nanoclusters was found to be 53 ± 6 K along the [012] direction and 86 ± 9 K along the [110] …

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Localized Surface Plasmon Resonance Of Single Silver Nanoparticles Studied By Dark-Field Optical Microscopy And Spectroscopy, Wei Cao, Tao Huang, Xiao-Hong Nancy Xu, Hani E. Elsayed-Ali Jan 2011

Localized Surface Plasmon Resonance Of Single Silver Nanoparticles Studied By Dark-Field Optical Microscopy And Spectroscopy, Wei Cao, Tao Huang, Xiao-Hong Nancy Xu, Hani E. Elsayed-Ali

Electrical & Computer Engineering Faculty Publications

Localized surface plasmon resonance (LSPR) of Ag nanoparticles (NPs) with different shapes and disk-shaped Ag NP pairs with varying interparticle distance is studied using dark-field optical microscopy and spectroscopy (DFOMS). Disk-, square-, and triangular-shaped Ag NPs were fabricated on indium tin oxide-coated glass substrates by electron beam lithography. The LSPR spectra collected from single Ag NPs within 5×5 arrays using DFOMS exhibited pronounced redshifts as the NP shape changed from disk to square and to triangular. The shape-dependent experimental LSPR spectra are in good agreement with simulations using the discrete dipole approximation model, although there are small deviations in the …

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Special Issue On Plenary And Invited Papers From Icops 2010, Ravi P. Joshi, Xinpei Lu, Yukinori Sakiyama Jan 2011

Special Issue On Plenary And Invited Papers From Icops 2010, Ravi P. Joshi, Xinpei Lu, Yukinori Sakiyama

Electrical & Computer Engineering Faculty Publications

HE 37th IEEE International Conference on Plasma Science (ICOPS) was held in Norfolk, VA, from June 20 to June 24, 2010. The technical program combined seven technical-related areas of plasma science and a range of diverse topics. A total of 562 abstracts from 37 countries were accepted, and the technical program included four plenary talks. There were 217 oral and 345 poster presentations. The plenary talks were given by Prof. L. Boufendi on Dusty Plasmas, Prof. E. Kunhardt on Non-Equilibrium Plasma Sources, Dr. K. S. Budil on High Energy Density Physics, and Dr. M. Thumm on the use of gyrotrons …

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Coupled Photonic Crystal Micro-Cavities With Ultra-Low Threshold Power For Stiumulated Raman Scattering, Qiang Liu, Zhengbiao Ouyang, Sacharia Albin Jan 2011

Coupled Photonic Crystal Micro-Cavities With Ultra-Low Threshold Power For Stiumulated Raman Scattering, Qiang Liu, Zhengbiao Ouyang, Sacharia Albin

Electrical & Computer Engineering Faculty Publications

We propose coupled cavities to realize a strong enhancement of the Raman scattering. Five sub cavities are embedded in the photonic crystals. Simulations through finite-difference time-domain (FDTD) method demonstrate that one cavity, which is used to propagate the pump beam at the optical-communication wavelength, has a Q factor as high as 1.254 × 108 and modal volume as small as 0.03μm3 (0.3192(λ/n)3). These parameters result in ultra-small threshold lasing power ~17.7nW and 2.58nW for Stokes and anti-Stokes respectively. The cavities are designed to support the required Stokes and anti-Stokes modal spacing in silicon. The proposed structure …

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Potential For Speciation In Mammals Following Vast, Late Miocene Volcanic Interruptions In The Pacific Northwest, Ryan Thomas Mckenna Jan 2011

Potential For Speciation In Mammals Following Vast, Late Miocene Volcanic Interruptions In The Pacific Northwest, Ryan Thomas Mckenna

Dissertations and Theses

The impact of large-scale volcanic eruptions on landscapes can affect many processes ranging from interrupting or redirecting regional soil forming processes and hydrological systems to generating temporary changes in global climate. Though more studies exist every year, less is known of the direct impact of large-scale volcanic eruptions on ecosystems and extinction, while even less is known of their impact on speciation. In deposits throughout the Pacific Northwest a special combination and association of volcanic magnitude with palaeoecological yield frequently presents unique prospects for inquiry. In this study, particular attention is given to large, late Miocene ash-flow tuffs of central …

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Diffuse-Charge Dynamics Of Ionic Liquids In Electrochemical Systems, Hui Zhao Jan 2011

Diffuse-Charge Dynamics Of Ionic Liquids In Electrochemical Systems, Hui Zhao

Mechanical Engineering Faculty Research

We employ a continuum theory of solvent-free ionic liquids accounting for both short-range electrostatic correlations and steric effects (finite ion size) [Bazant et al., Phys. Rev. Lett. 106, 046102 (2011)] to study the response of a model microelectrochemical cell to a step voltage. The model problem consists of a 1-1 symmetric ionic liquid between two parallel blocking electrodes, neglecting any transverse transport phenomena. Matched asymptotic expansions in the limit of thin double layers are applied to analyze the resulting one-dimensional equations and study the overall charge-time relation in the weakly nonlinear regime. One important conclusion is that our …

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Ignition Of A Large Volume Plasma With A Plasma Jet, M. Laroussi, M. A. Akman Jan 2011

Ignition Of A Large Volume Plasma With A Plasma Jet, M. Laroussi, M. A. Akman

Electrical & Computer Engineering Faculty Publications

Here we report on a method to generate a long plasma plume and to ignite a large volume plasma by means of the jet. The plasma plume is generated by our tube reactor and then introduced into a chamber where the pressure is controlled. We discovered there are three operating phases:Aphasewhere the plume length remains approximately constant, followed by a second phase where the jet increases in length as the pressure decreases. Then at pressures below 70 Torr a mode transition occurs where the plume length decreases and the plasma expands until the entire chamber is filled.

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