Physical Sciences and Mathematics Commons^™

Determining Ground-Level Composition And Concentration Of Particulate Matter Across Regional Areas Using The Himawari-8 Satellite, Miles Sowden

Theses: Doctorates and Masters

Speciated ground-level aerosol concentrations are required to understand and mitigate health impacts from dust storms, wildfires and other aerosol emissions. Globally, surface monitoring is limited due to cost and infrastructure demands. While remote sensing can help estimate respirable (i.e. ground level) concentrations, current observations are restricted by inadequate spatiotemporal resolution, uncertainty in aerosol type, particle size, and vertical profile. One key issue with current remote sensing datasets is that they are derived from reflectances observed by polar orbiting imagers, which means that aerosol is only derived during the daytime, and only once or twice per day.

Sub-hourly, infrared (IR), geostationary …

Climate And Surging Of Donjek Glacier, Yukon, Canada, Ellyn M. Enderlin

Geosciences Faculty Publications and Presentations

Links between climate and glacier surges are poorly understood but are required to enable prediction of surges and mitigation of associated hazards. Here, we investigate the role of snow accumulation, rain, and temperature on surge periodicity, area changes, and timing of surge initiation since the 1930s at Donjek Glacier, Yukon, Canada. Snow accumulation measured in three ice cores collected at Eclipse Icefield indicates that a cumulative accumulation of 15.5 ± 1.46 or 16.6 ± 2.0 m w.e. occurred in the ten to twelve years between each of its last eight surges, depending on ice motion spatiotemporal offset corrections. Although we …

Modeling The Effects Of Climate Change On Streamflow And Stream Temperature In The South Fork Of The Stillaguamish River, Katherine Mary Clarke

WWU Graduate School Collection

The Stillaguamish River in northwest Washington State is an important regional water resource for local agriculture, industry, and First Nations tribes and a critical habitat for several threatened and endangered salmonid species, including the Chinook salmon. The river is currently subject to a temperature total maximum daily load, so it is important to understand how projected climate change will affect future stream temperatures and thus salmon populations. Snowpack is the main contributor to spring and summer streamflow and helps to mitigate stream temperatures as air temperatures rise through the summer in the South Fork of the Stillaguamish River. I used …

Spatial And Temporal Trends Of The Annual First Detections Of Paralytic Shellfish Toxin In Puget Sound, Wa, Margaret Taylor

WWU Graduate School Collection

Since the 1950s, the Washington State Department of Health has routinely monitored the suite of toxins in shellfish associated with Paralytic Shellfish Poisoning. These toxins, known collectively as Paralytic Shellfish Toxins, are produced by species of the marine dinoflagellate in the genus Alexandrium. The role of the monitoring program is primarily to protect public health and safety; and therefore, use of these data for long-term statistical analysis has been limited due to opportunistic and irregular sampling of various shellfish species in space and time. However, some studies suggest that initiation of these toxic events have recently shifted to earlier …

Interaction, Collaboration And Content Creation In Informal Online Learning Environments: Multidimensional Analyses Of Longitudinal Data From The Scratch Coding Community, Seung B. Lee

Theses and Dissertations

Despite rising levels of participation by children and adolescents in large, informal online learning communities, there has been limited research examining the role that social dynamics play on the online behavior of young users. In this context, this mixed-methods longitudinal study aimed to investigate the relationship between interaction, collaboration and content creation through the analysis of user-generated comments and log-data from the Scratch platform. The research focused on more than 45,000 comments associated with the online activity of 200 randomly selected participants over a period of three months in early 2012. A combination of methodological techniques was applied in the …

Bird And Native Bee Responses To Habitat Treatments, Emily Bea Oja

Graduate Student Theses, Dissertations, & Professional Papers

As forests across the United States have been altered due to fire suppression in the last century, their structure has been altered, resulting in increased fuel loads. Subsequently, managers have been increasingly implementing habitat treatments including prescribed burning, mechanical thinning, and a combination of both treatments to reduce fuel loads and enhance habitat for ungulates. The Rocky Mountain Elk Foundation has partnered with agencies to complete over 10,000 of these treatments across the United States to enhance elk habitat. As treatment impacts to other wildlife species are not well understood, we evaluated the effects of these treatments on the bird …

Timing And Conditions Of Metamorphism In The Cascades Crystalline Core From Garnet Lu-Hf And Sm-Nd Geochronology, Peter Baker

WWU Graduate School Collection

The Chiwaukum Schist and Tonga Formation of Cascades Crystalline Core experienced three distinct metamorphic events: (M1) an early metamorphism that predates regional pluton emplacement, (M2) low-pressure contact metamorphism in the aureoles of the Mount Stuart batholith and Beckler Peak pluton, and (M3) regional Barrovian metamorphism. The timing of these distinct metamorphic events is critical to testing models for the tectonic evolution of the region and mechanisms that lead to burial of rocks within the orogen. I present new garnet Lu-Hf and Sm-Nd isochrons, average pressure and temperature calculations, and pseudosection modeling from the Chiwaukum Schist and Tonga Formation in order …

Polybenzoxazine-Grafted Composites: Accelerated Polymerization Of Benzoxazine Resins From Bulk- To Microscale Mesylated Materials, Cassidy L. Crickmore

WWU Graduate School Collection

Benzoxazine-based resins often afford high modulus and high glass transition polymers that are desirable for creating safe and reliable thermoset parts and composites. However, benzoxazine resins have had limited widespread deployment into industry due to their high cure temperature. By blending functionalized glass substrates with the benzoxazine monomer, we hypothesize that the cure temperature of thermosetting resin can be lowered. The structure and purity of the particles, determined by NMR and FTIR, will be presented. DSC studies on the stability and cure accelerating properties of blends composed of functionalized glass substrates and benzoxazine monomer will be determined and compared against …

Allylic Benzoate Reductions: A Study On Stereospecificity, Michael A. Leitch

WWU Graduate School Collection

Herein we report results from experiments aimed at better understanding SmI2(H2O)n reductions of allylic benzoates adjacent to a trisubstituted alkene. When flanked by both a chelating group and stereodirecting group, these reactions can occur with complete regioselectivity and good diastereoselectivity (up to 90:10). Initial experiments suggested that the reaction was stereospecific to alkene geometry. However, further experimentation has revealed that the alkene stereospecificity is substrate dependent. For instance, if the geminal alkene substituents are alkyl, results show the reaction to be stereospecific, but if one of the substituents is a phenyl group the reaction is still stereoselective but not stereospecific. …

Plasmonic-Based Hybrid Nanomaterial: From Synthesis To Application, Maggie Wang

WWU Graduate School Collection

Gold nanoparticles, particularly gold nanorods, have been widely used as sensors and imaging agents due to their unique and tunable morphology-dependent properties and intriguing plasmonic resonance. However, the increasing need of new materials with enhanced properties and functionality led scientists to discover novel hybrid nanomaterials, which involves the formation of two or more components into one nanoplatform. Hence, gold nanorod-based hybrid nanomaterials exhibit simultaneous synergistic effects between the phenomenal plasmonic properties from gold nanorods and the intrinsic properties of the other constituents. The functionality of gold nanorod-based hybrid nanomaterials greatly increases due to its enhanced performance characteristics, which directly impacts …

Using Multispectral Imagery To Interrogate Deposition, Alteration, And Weathering Across Curiosity Rover’S Traverse In Gale Crater, Mars, Christina Seeger

WWU Graduate School Collection

Since landing in 2012, the Mars Science Laboratory (MSL) Curiosity rover has explored over 20 kilometers of Gale crater, climbing almost 400 meters in elevation. The fluvio-deltaic, lacustrine, and aeolian sediments in the crater have been well documented by Curiosity’s suite of in situ and remote science instruments. Indeed, they have traced chemical trends that track changes in lithology and diagenesis over the study area—though most instruments only sample individual rock, vein, and soil targets at a very small scale. The Mast Camera (Mastcam) has periodically acquired much larger (meter-scale) multispectral, visible to near-infrared observations of outcrops throughout this stratigraphic …

Incorporating Characteristics Of Gene Drive Engineered Ae. Aegypti As Methods To Reduce Dengue And Zika Virus Into The Bayesian Network – Relative Risk Model, Using Ponce, Puerto Rico As A Case Study, Steven R. Eikenbary

WWU Graduate School Collection

This study proposes the use of the Bayesian network relative risk model (BN-RRM) to estimate the risk associated with the release of gene drives as vectors to control disease, using Ponce, Puerto Rico as a case study. Bayesian networks are an appropriate risk assessment tool for quantitatively and probabilistically examining complex systems involving multiple stressors acting on multiple endpoints in a wide variety of situations. The emerging field of synthetic biology has the capacity to drastically alter ecological systems with the use of gene drive engineered organisms as a method to alter population dynamics. The purpose of the release of …

Incorporating Climate Change Predictions In Ecological Risk Assessment: A Bayesian Network Relative Risk Model For Chinook Salmon In The Skagit River Watershed, Eric J. Lawrence

WWU Graduate School Collection

Climate change is expected to have widespread impacts on future ecosystem services in the Puget Sound and around the world. It is important that climate change be included in ecological risk assessment so that changing climate variables and potential interactive effects with chemical stressors can be taken into account. In this research, I focused on the question of how water temperature changes generated by climate change interact with organophosphate pesticide toxicity to affect Chinook salmon (Oncorhynchus tshawytscha) population size in the Skagit River, WA. To answer this question, I conducted an ecological risk assessment using the Bayesian network …

Carbodiimides: Templates For Covalent Adaptable Networks And Post Polymerization Modification, Alberto J Melchor Bañales

WWU Graduate School Collection

The global increase in plastic waste has negatively impacted the environment, human health, and economy. Plastics that lack recyclability, such as thermosets are some of the main culprits. To help address this issue, reactive functional groups can be incorporated in macromolecules, enabling straightforward post-polymerization modification (PPM) that can enhance their ability to be recycled. This thesis studied carbodiimides as a reactive functional group for facile PPM with amines through a catalyst-free transformation to N,Nʹ,Nʺ-trisubstituted guanidines. Small molecule studies showed that N,Nʹ,Nʺ-trisubstituted guanidines underwent a reversible thermal exchange reaction without a catalyst. The newly found thermal exchange reaction, termed thermal guanidine …

Synthesis And Characterization Of Earth Abundant Metal Phosphide Photocatalysts For The Reverse Water Gas Shift Reaction, John D. Springer

WWU Graduate School Collection

This thesis work focuses on the synthesis and characterization of photocatalysts composed of metal phosphide nanoparticles on a titania (TiO2) support for the conversion of carbon dioxide (CO2) to carbon monoxide (CO) via the reverse water gas shift (RWGS) reaction. The CO product can be subsequently converted to solar fuels such as methanol (CH3OH), thus lowering the carbon footprint associated with the combustion of liquid fuels. The photocatalysts are composed of a tunable light absorber, indium-gallium phosphide (InxGa1-xP), and nickel phosphide (Ni2P) as a co-catalyst, on TiO2. The photocatalysts are characterized using diffuse reflectance ultraviolet-visible (UV-Vis) spectroscopy to determine band …

Bio-Preservation Potential Of Sediment In Eberswalde Crater, Mars, Cory Hughes

WWU Graduate School Collection

Within Eberswalde crater, Mars, is one of the most well-preserved river delta deposits identified within Mars’ rock record, and visually traceable from the deposit, is the partially-intact watershed that fed the paleo-lake that once resided within the crater basin. Aqueous alteration minerals, smectite clays and opaline silica, have been previously identified within the deposit, however the origin of those minerals is not well understood. Through analysis of topographic and hyperspectral data, we seek to ascertain the origin and provenance of these minerals to better understand their formative conditions and formation age. We will also assess Eberswalde crater’s potential as a …

Slip Rates And Kinematics Of Active Crustal Faults In The Central Oregon Cascades, Katherine Alexander

WWU Graduate School Collection

New cosmogenic ³He chronologies and surficial geologic mapping constrain the age of glacial deposits and slip rates of predominantly normal faults in the White Branch and Dilman Meadows fault zones in central Oregon, USA, over the last ca. ~80 kyr. Our mapping of glacial landforms and deposits distinguishes three primary episodes of glacial deposition in the White Branch fault zone. Twenty-two new cosmogenic ³He surface exposure dates indicate that the youngest glacial unit represents a last glacial maximum deposit (ca. 19.4 +10.1/-6.2 kyr). Mapping of outwash terrace surfaces and deposits in the Dilman Meadows fault zone, constrained by …

Lsc Fabrication And Design: Bulk Polymerization And Ultrathin Architectures, Justin T. Doyle

WWU Graduate School Collection

Renewable energy technologies that access underutilized spaces in the built environment will need to be implemented, on a large scale, to curtail trending increases in global temperature. Luminescent Solar Concentrators (LSCs) are one such technology. They employ luminophores doped into polymer sandwiched in between glass plates, that redirect sunlight to the device periphery where photovoltaics are attached, producing power. Current devices do not have high enough efficiencies for commercialization. One of the biggest barriers is fluorophore aggregation which causes waveguide refractive index fluctuations which result in parasitic losses from the waveguide. In this work Copper Indium Disulfide/Zinc Sulfide (CIS/ZnS) quantum …

Spatially Variable Syn- And Post-Orogenic Exhumation Of The Appalachian Mountains From Apatite And Zircon (U-Th)/He Thermochronology, Luke Coughtry Basler

Honors Projects

We present zircon and apatite (U-Th)/He (ZHe, closure temperature = 150-200ºC; AHe, closure temperature = 45-80ºC) results from two study regions in the Appalachians Mountains to investigate the timing, rates, and spatial trends of exhumation during Alleghanian orogenesis, Atlantic rifting, and post-rift passive margin conditions. Within West Virginia and Virginia, 10 ZHe dates along an across-orogen transect display an eastward younging trend, from ~425 million years (Ma) in the western Appalachian Plateau province, to ~250-300 Ma in the central Valley-Ridge fold-thrust belt, and 163 ± 29 Ma in the eastern Piedmont. Inverse thermal modeling of ZHe data using external geologic …

Singlet Fission In A Hexacene Dimer: Energetics Dictate Dynamics, Samuel N. Sanders, Elango Kumarasamy, Kealan J. Fallon, Matthew Y. Sfeir, Luis M. Campos

Publications and Research

Singlet fission (SF) is an exciton multiplication process with the potential to raise the efficiency limit of single junction solar cells from 33% to up to 45%. Most chromophores generally undergo SF as solid-state crystals. However, when such molecules are covalently coupled, the dimers can be used as model systems to study fundamental photophysical dynamics where a singlet exciton splits into two triplet excitons within individual molecules. Here we report the synthesis and photophysical characterization of singlet fission of a hexacene dimer. Comparing the hexacene dimer to analogous tetracene and pentacene dimers reveals that excess exoergicity slows down singlet fission, …

Double Inclusive Small-X Gluon Production And Their Azimuthal Correlations In A Biased Ensemble, Gary Kapilevich

Publications and Research

We consider double gg → g production in the presence of a bias on the unintegrated gluon distribution of the colliding hadrons or nuclei. Such bias could be due to the selection of configurations with a greater number of gluons or higher mean transverse momentum squared or, more generally, due to a modified spectral shape of the gluon distribution in the hadrons. Hence, we consider reweighted functional averages over the stochastic ensemble of small-x gluons. We evaluate explicitly the double inclusive gluon transverse momentum spectrum in high-energy collisions, and their azimuthal correlations, for a few simple examples of biases.

Deriving Statistical Inference From The Application Of Artificial Neural Networks To Clinical Metabolomics Data, Kevin M. Mendez

Theses: Doctorates and Masters

Metabolomics data are complex with a high degree of multicollinearity. As such, multivariate linear projection methods, such as partial least squares discriminant analysis (PLS-DA) have become standard. Non-linear projections methods, typified by Artificial Neural Networks (ANNs) may be more appropriate to model potential nonlinear latent covariance; however, they are not widely used due to difficulty in deriving statistical inference, and thus biological interpretation. Herein, we illustrate the utility of ANNs for clinical metabolomics using publicly available data sets and develop an open framework for deriving and visualising statistical inference from ANNs equivalent to standard PLS-DA methods.

Web Content Management System And Accessibility Awareness: A Comparative Study Of Novice Users And Accessibility Outcomes, Fatima Artiba Diaz

Theses: Doctorates and Masters

Since its creation, the Web has progressively developed and become a vital source of information in every domain and for almost all people. It is crucial to guarantee that the information contained on the Web is available for everyone, especially for people with special needs. Removing accessibility barriers is fundamentally based on tools, skills and support of all contributors, particularly the content creators, to ensure information is navigable and usable in the context of the end users experience. Web Content Management Systems play a significant role in structuring, storing and provision content to the Web and have evolved to address …

An Investigation Into The Spatial Distribution, Habitat Selection And Resource Usage Of The Red Fox (Vulpes Vulpes) Inhabiting Urban Reserves Within Perth, Western Australia, Michael Thomas Main

Theses: Doctorates and Masters

I attempted to track a population of urban foxes in Kings Park, but due to collar failure, only one collar was retrieved. The GPS telemetry data from this fox produced home range estimates for minimum convex polygon (MCP) and kernel density (KD) of 0.302 km² and 0.331 km², respectively. The fox was predominantly active at night, with a ten-fold increase in movement during nocturnal periods when compared to daytime movements. Roads and man-made tracks were important for facilitating movement of the fox through its home range, with almost 97% of location fixes recorded within 100m of these features. The fox …

Local Binary Pattern Based Algorithms For The Discrimination And Detection Of Crops And Weeds With Similar Morphologies, Vi Nguyen Thanh Le

Theses: Doctorates and Masters

In cultivated agricultural fields, weeds are unwanted species that compete with the crop plants for nutrients, water, sunlight and soil, thus constraining their growth. Applying new real-time weed detection and spraying technologies to agriculture would enhance current farming practices, leading to higher crop yields and lower production costs. Various weed detection methods have been developed for Site-Specific Weed Management (SSWM) aimed at maximising the crop yield through efficient control of weeds. Blanket application of herbicide chemicals is currently the most popular weed eradication practice in weed management and weed invasion. However, the excessive use of herbicides has a detrimental impact …

Memory And Resource Leak Defects And Their Repairs In Java Projects, Mohammadreza Ghanavati, Diego Costa, Janos Seboek, David Lo, Artur Andrzejak

Research Collection School Of Computing and Information Systems

Despite huge software engineering efforts and programming language support, resource and memory leaks are still a troublesome issue, even in memory-managed languages such as Java. Understanding the properties of leak-inducing defects, how the leaks manifest, and how they are repaired is an essential prerequisite for designing better approaches for avoidance, diagnosis, and repair of leak-related bugs. We conduct a detailed empirical study on 452 issues from 10 large opensource Java projects. The study proposes taxonomies for the leak types, for the defects causing them, and for the repair actions. We investigate, under several aspects, the distributions within each taxonomy and …

Systematic Classification Of Attackers Via Bounded Model Checking, Eric Rothstein-Morris, Jun Sun, Sudipta Chattopadyay

Research Collection School Of Computing and Information Systems

In this work, we study the problem of verification of systems in the presence of attackers using bounded model checking. Given a system and a set of security requirements, we present a methodology to generate and classify attackers, mapping them to the set of requirements that they can break. A naive approach suffers from the same shortcomings of any large model checking problem, i.e., memory shortage and exponential time. To cope with these shortcomings, we describe two sound heuristics based on cone-of-influence reduction and on learning, which we demonstrate empirically by applying our methodology to a set of hardware benchmark …

Lightweight Sharable And Traceable Secure Mobile Health System, Yang Yang, Ximeng Liu, Robert H. Deng, Yingjiu Li

Research Collection School Of Computing and Information Systems

Mobile health (mHealth) has emerged as a new patient centric model which allows real-time collection of patient data via wearable sensors, aggregation and encryption of these data at mobile devices, and then uploading the encrypted data to the cloud for storage and access by healthcare staff and researchers. However, efficient and scalable sharing of encrypted data has been a very challenging problem. In this paper, we propose a Lightweight Sharable and Traceable (LiST) secure mobile health system in which patient data are encrypted end-to-end from a patient’s mobile device to data users. LiST enables efficient keyword search and finegrained access …

A Guide To Ligo–Virgo Detector Noise And Extraction Of Transient Gravitational-Wave Signals, B. P. Abbott, R. Abbott, Teviet Creighton, Mario C. Diaz, Soma Mukherjee, Volker Quetschke, Malik Rakhmanov, K. E. Ramirez, Satzhan Sitmukhambetov, Robert Stone, D. Tuyenbayev, W. H. Wang, A. K. Zadrozny

Physics and Astronomy Faculty Publications and Presentations

The LIGO Scientific Collaboration and the Virgo Collaboration have cataloged eleven confidently detected gravitational-wave events during the first two observing runs of the advanced detector era. All eleven events were consistent with being from well-modeled mergers between compact stellar-mass objects: black holes or neutron stars. The data around the time of each of these events have been made publicly available through the gravitational-wave open science center. The entirety of the gravitational-wave strain data from the first and second observing runs have also now been made publicly available. There is considerable interest among the broad scientific community in understanding the data …

Human Path Prediction Using Auto Encoder Lstms And Single Temporal Encoders, Hayden Hudgins

Master's Theses

Due to automation, the world is changing at a rapid pace. Autonomous agents have become more common over the last several years and, as a result, have created a need for improved software to back them up. The most important aspect of this greater software is path prediction, as robots need to be able to decide where to move in the future. In order to accomplish this, a robot must know how to avoid humans, putting frame prediction at the core of many modern day solutions. A popular way to solve this complex problem of frame prediction is Auto Encoder …