Physical Sciences and Mathematics Commons^™

Compounding Fire Disturbance History Encourages Coast Redwood (Sequoia Sempervirens) Regeneration And Community Dominance, Matthew R. Brousil

Master's Theses

Disturbance is fundamental to forest ecosystem function and overall health, but climate change is likely to increase both disturbance frequency and intensity in the future. Forests subject to increasingly frequent and intense disturbances are more likely to experience compounding disturbance effects. Compounding disturbances may exert unpredicted, non-additive stresses on ecosystems, leading to novel conditions that may exceed the capacity for local species to survive and regenerate. I further hypothesize that compounding disturbances could create conditions misaligned with species’ adaptations by altering physical and chemical growing conditions in forest soils, affecting forest composition, structure, and, subsequently, function for many years following …

Elasticity Of Cylindrical Black Holes, Conrad Pearson

Physics

Black holes are regions of strong gravity, and are often regarded as behaving like drops of fluid. When this line of thought is applied to cylindrical black holes (black cylinders), a mapping can be made between known instabilities for black cylinders and ordinary fluid cylinders. However, this known correlation is increasingly less accurate for lower spatial dimensions, and I seek to correct this discrepancy in this thesis. By considering soft solids instead of pure fluids, elastic energy can be included, which brings us closer to a direct comparison. In improving this mapping, it becomes possible to better understand the behavior …

Field Emissions Of (Hydro)Chlorofluorocarbons And Methane From A California Landfill, Alexander H. Sohn

Master's Theses

A comprehensive field investigation was conducted at Potrero Hills Landfill (PHL) located in Suisun City, California to quantify emissions of twelve (hydro)chlorofluorocarbons (i.e. F-gases). The specific target constituents for this study included CFC-11, CFC-12, CFC-113, CFC-114, HCFC-21, HCFC-22, HCFC-141b, HCFC-142b, HCFC-151a, HFC-134a, HFC-152a, and HFC-245fa. The majority of the F-gas emission studies have been conducted outside of the United States and very limited field landfill emission data are available in the United States. Because of historical usage of blowing agents in insulation foams including CFC-11, HCFC-142b, HFC-134a, and HFC-245fa, models reported in literature predicted high F-gas emissions from a landfill …

Leveraging The Final Project To Improve Student Motivation In Introductory Digital Design Courses, Andrew Danowitz

Computer Science and Software Engineering

Student retention rates in engineering, especially among traditionally underrepresented groups, remain an obstacle to training a large, diverse engineering workforce. The NSF's Science and Engineering Indicators 2016 indicate that of students entering college with an intent to major in engineering, only 63% graduate with an engineering degree [1]. With research suggesting that misperceptions or a lack of knowledge about what work in a certain field is like can deter students from studying that discipline [2], [3], it is possible that providing a meaningful project experience at the introductory level could provide a strong positive impact on retention rates. This could …

Atomic Tiles: Manipulative Resources For Exploring Bonding And Molecular Structure, Alan L. Kiste, Rebecca G. Hooper, Gregory E. Scott, Seth Bush

Chemistry and Biochemistry

A simple manipulative resource, Atomic Tiles, is described for scaffolding the learning of Lewis structures without using algorithmic, rule-based methods of drawing. Students use Atomic Tiles to (1) create models of bonding that lead to drawing Lewis structures, (2) use the structures they create to infer patterns required for rational structures and common organic functional groups, (3) translate between Lewis structures and molecular models, and (4) use molecular models to identify isomers.

Large-Scale Outflows In Luminous Qsos Revisited: The Impact Of Beam Smearing On Agn Feedback Efficiencies, Bernd Husemann, Julia Scharwächter, Vardha N. Bennert, V. Manieri, Jong-Hak Woo, Darshan Kakkad

Physics

Context. Feedback from active galactic nuclei (AGN) is thought to play an important role in quenching star formation in galaxies. However, the efficiency with which AGN dissipate their radiative energy into the ambient medium remains strongly debated.

Aims. Enormous observational efforts have been made to constrain the energetics of AGN feedback by mapping the kinematics of the ionized gas on kpc scale. We study how the observed kinematics and inferred energetics are affected by beam smearing of a bright unresolved narrow-line region (NLR) due to seeing.

Methods. We re-analyse optical integral-field spectroscopy of a sample of twelve luminous unobscured quasi-stellar …

Weights And Balances: Integrating Models For Prevention And Response To Southern California Offshore Oil Spills, Carmen Watts Clayton, Amoret Bunn

STAR Program Research Presentations

Licensing offshore oil and gas reserves in the United States waters are overseen by the U.S. Department of the Interior’s Bureau of Safety and Enforcement (BSEE). The licensing application includes planning for any worst-case oil spill scenario between BSEE and the applicant based on lessons learned from historic offshore spills such as the Deepwater Horizon (2010), Exxon Valdez (1989), and the Union Oil Platform Blowout (1969). The process for planning to respond to oil spills involves coordination with multiple agencies, trustees, and stakeholders to ensure that oil spill responses consider multiple factors, including ecologically sensitive species, commercial transportation and fisheries, …

Effect Of Surface Treatment On Liquid Adhesion Inside 3-D Structures, Madani A. Khan, Jeffrey Alston, Andrew Guenthner, Jacob Zavala

STAR Program Research Presentations

This study explores the relationship between chemical surface treatments on the interior of glass tubes and their resistance to fluid flow. By treating the interior of the tubes with functional silanes we can decrease or increase the interaction of the tube walls with the fluid column, which translates to changes in fluid column height for a given pressure differential. Resistance to fluid flow is quantified by using the tubes as integral parts of a barometric pressure column and measuring the changes in column height as the fluid is pulled into the tube by a set pressure differential. The barometric pressure …

Examination On The Efficacy Of Noah-Multiparameterization (Noah-Mp) As A New Land Model In Earth Systems Modeling, Nicholas Rubel, Guo-Yue Niu, Ning Ma

STAR Program Research Presentations

Along with measurements and observations, models (both physical and mathematical) are among the most important tools used by Earth scientists to make hypotheses, test hypotheses, and form predictions. These models are based upon information and theories already believed to be true. As newer and better information is discovered, the models can become more accurate and precise. Mathematical models, sometimes called numerical models, also rely on technology; as the technology used to make models becomes more advanced, more complex models can be made and used to test more variables at once. This report examines a new mathematical model called Noah-Multiparameterization (Noah-MP) …

Characterization Of S-Swcnt/Pf-Pd Dispersions And Networks, Tamara N. El-Hayek Ms., Jeffrey Blackburn, Andrew Ferguson, Tammy Pheuphong

STAR Program Research Presentations

Single-Walled Carbon Nanotubes (SWCNTs) are being investigated for their use in a wide variety of renewable energy applications. Their unique physical properties contribute to desirable traits such as a high carrier mobility, strong optical absorption and tunable electronic band gap. Unfortunately, due to variability in certain parameters, SWCNTs are limited in their application. The major drawback is that SWCNTs are variable in size and type and typical synthetic methods are not selective. As a result, selective methods must be developed in order to sort these tubes and extract those which are desirable for a particular application. Though there are several …

Optimizing The Telescope Assembly Alignment Simulator For Sofia, Zoe E. Sharp, Alex Quyenvo, Jennifer Briggs, Brian Eney

STAR Program Research Presentations

The Stratospheric Observatory for Infrared Astronomy (SOFIA) conducts research on a modified Boeing 747sp aircraft. By using a variety of infrared science instruments mounted on a 2.7 meter telescope, researchers can make discoveries about the galactic center, star formation, and various topics associated with a deeper understanding of our universe. To efficiently collect data through the SOFIA instruments, the instruments must be tested and prepared prior to being placed on the aircraft. Therefore, with the use of the Telescope Assembly Alignment Simulator (TAAS), researchers can design and construct improvements needed for these instruments to efficiently perform while in flight. The …

Community Outreach With Play-Doh® Electronics, Thomas J. Bensky, William Bensky

Physics

It never fails: you’re in your office and the phone rings. Your department head says, “Hi! Fifty kids are coming to campus in 30 minutes. Can you meet with them and give them a one-hour hands-on activity that will make them excited about physics?” Likely you’ll run to your demonstration room and grab anything that’ll generate a bright light or cause something to explode or levitate, right? In recent years, we’ve taken a more systematic approach to hosting visitors by developing a ready-to-go hands-on activity that provides opportunities for learning about DC electric circuits.

An Analysis Of The Microseismic Peak At Ligo Hanford Observatory, Nathan Sweem

STAR Program Research Presentations

The Laser Interferometer Gravitational-Wave Observatory (LIGO) consists of two facilities, LIGO Hanford Observatory (LHO) and LIGO Livingston Observatory (LLO). Gravitational-wave astronomy began when LIGO observed gravitational-waves for the first time in 2015 during the inaugural observation run (01) of the advanced detector era. Isolation of LIGO detectors from seismic noise is necessary to achieve a desired level of performance. Analysis of seismic noise is essential to make improvements in seismic isolation, and to validate gravitational-wave candidates with a high degree of certainty. Hourly trends of seismic noise in the 0.1 – 0.3 Hz frequency band from Guralp CMG-40T three-axis seismometers …

Measurement And Modeling Of Cosmic Ray Exposure For Supercdms Dark Matter Detectors., Kameron Mccall, John Orrell, Jared Yamaoka

STAR Program Research Presentations

Dark matter is an unknown type of matter that composes roughly 27% of the observable universe and, as cosmological structure models suggest, the earth should be passing through a “dark halo” of this unknown matter present in the Milky Way galaxy. As we pass through this halo, the Super Cryogenic Dark Matter Search (SuperCDMS) experiment aims to directly detect dark -matter particles. Though many dark matter particle candidates exist, SuperCDMS focuses on the detection of particles called WIMPS (weakly interacting massive particles) as predicted by super-symmetric theories beyond the standard model. Due to the high-sensitivity of the germanium detectors employed, …

Exploring Mathematical Strategies For Finding Hidden Features In Multi-Dimensional Big Datasets, Tri Duong, Fang Ren, Apurva Mehta

STAR Program Research Presentations

With advances in technology in brighter sources and larger and faster detectors, the amount of data generated at national user facilities such as SLAC is increasing exponentially. Humans have a superb ability to recognize patterns in complex and noisy data and therefore, data is still curated and analyzed by humans. However, a human brain is unable to keep up with the accelerated pace of data generation, and as a consequence, the rate of new discoveries hasn't kept pace with the rate of data creation. Therefore, new procedures to quickly assess and analyze the data are needed. Machine learning approaches are …

Testing Predictions Used To Build An Agrivoltaics Installation On A Small-Scale Educational Model, Katie Kinney, Rebecca Minor, Greg Barron-Gafford

STAR Program Research Presentations

Models are valuable tools for explaining and testing systems. Small-scale models can be especially useful for educational purposes. For models to be useful, they have to accurately depict the larger system that they are describing. A novel man-made system, known as an agrivoltaic structure, is being constructed at Biosphere 2 near Oracle, Arizona. The word agrivoltaic is a combination of agriculture and photovoltaics, or solar farming. My research involved creating a small-scale version of this system for educational purposes. The model of this system tested two predictions: that plants will grow better in the shade of a panel and that …

Examination On The Efficacy Of Noah-Multiparameterization (Noah-Mp) As A New Land Model In Earth Systems Modeling, Nicholas Rubel, Guo-Yue Niu, Ning Ma

STAR Program Research Presentations

Along with measurements and observations, models (both physical and mathematical) are among the most important tools used by Earth scientists to make hypotheses, test hypotheses, and form predictions. These models are based upon information and theories already believed to be true. As newer and better information is discovered, the models can become more accurate and precise. Mathematical models, sometimes called numerical models, also rely on technology; as the technology used to make models becomes more advanced, more complex models can be made and used to test more variables at once. This report examines a new mathematical model called Noah-Multiparameterization (Noah-MP) …

Gc Verification Of The Spacecraft Atmosphere Monitor, Jessica S. Castro, Richard D. Kidd, Jeffrey D. Hein

STAR Program Research Presentations

International Space Station crew members face the unique challenge of maintaining air quality due to the volatile organic compounds (VOCs) that have the potential to accumulate at unsafe levels. The Spacecraft Atmosphere Monitor (SAM) is a miniature gas chromatograph/mass spectrometer (GCMS) designed to measure major constituents (such as N₂, O₂ and CO₂) and trace VOCs within the cabin of the spacecraft. The gas chromatograph is responsible for separating the sample into its components in order to be characterized. The oven of the gas chromatograph must reach a temperature of 150°C in order to heat constituents …

Creating A Probabilistic Model For Wordnet, Lubomir Stanchev

Computer Science and Software Engineering

We present a probabilistic model for extracting and storing information from WordNet and the British National Corpus. We map the data into a directed probabilistic graph that can be used to compute the conditional probability between a pair of words from the English language. For example, the graph can be used to deduce that there is a 10% probability that someone who is interested in dogs is also interested in the word “canine”. We propose three ways for computing this probability, where the best results are achieved when performing multiple random walks in the graph. Unlike existing approaches that only …

Optimization And Coding Of A Lcls Control Program, Tanner M. Worden

STAR Program Research Presentations

SLAS’s, Linac Coherent Light Source (LCLS) also known as X-ray free-electron laser (XFEL) is the first X-ray laser of its kind. It gave Scientist from around the world the unique ability to observe the world at a subatomic level. Allowing for major advancements in the field of biological chemistry, drug science, material science and many more. Since the LCLS is a fairly unique scientific instrument, the demand for its use by the scientific community has always been high since it turned on back in 2009. This means that any and all time that the laser is not being used for …

Irrigation Efficiency Of Santa Rosa Island Cloud Forest Restoration Project, Rebecca Bernard, Kathryn Mceachern, Ken Niessen

STAR Program Research Presentations

Beginning in the 1800s, sheep and cattle ranching have caused significant erosion and devegetation of Santa Rosa Island, Channel Islands National Park. In an effort to contain what little soil is left and rebuild the native chaparral, the Cloud Forest Restoration Project is testing erosion control structures such as wattles, leaf litter fences and silt dams. This summer a drip irrigation system was installed along with fog capturing fences to supply water to native plants transplanted near the erosion control structures. As the project has grown, more irrigation has been added to increase the area available for transplanting. This irrigation …

The Close Agn Reference Survey (Cars): Mrk 1018 Returns To The Shadows After 30 Years As A Seyfert 1, R. E. Mcelroy, Bernd Husemann, S. M. Croom, T. A. Davis, Vardha N. Bennert, G. Busch, F. Combes, A. Eckart, M. Perez-Torres, M. Powell, J. Scharwächter, G. R. Tremblay, T. Urrutia

Physics

We report the discovery that the known “changing look” AGN Mrk 1018 has changed spectral type for a second time. New VLT-MUSE data taken in 2015 as part of the Close AGN Reference Survey (CARS) shows that the AGN has returned to its original Seyfert 1.9 classification. The CARS sample is selected to contain only bright type 1 AGN, but Mrk 1018’s broad emission lines and continuum, typical of type 1 AGN, have almost entirely disappeared. We use spectral fitting of the MUSE spectrum and previously available spectra to determine the drop in broad line flux and the Balmer decrement. …

A Comparison Of Solvent And Water-Borne Alkyd Coatings And The History Of Voc Regulations In The United States, Molly Elise Burns

Master's Theses

A Comparison of Solvent and Water-Borne Alkyd Coatings Abstract

Conventional solvent based alkyd coatings have gone out of favor due to concerns over volatile organic compound (VOC) content. However, due to recent focus on renewable raw materials, alkyds are making a comeback in waterborne form. Water based alkyd coatings are known to have poor shelf stability and corrosion resistance, as well as other problems during the formulation process. This project focused on comparing solvent borne to two types of water-borne alkyds, water reducible alkyds and alkyds emulsions. The purpose was to understand the differences between the three types of alkyds …

Density Functional Theory Based Electrolyte Design Formulation For Lithium-Sulfur Batteries, Cynthia Ly, Carolyn Sturges, Vijay Murugesan

STAR Program Research Presentations

Lithium-ion (Li-ion) batteries are commonly used in portable electronics such as cellphones and laptops. Most Li-ion batteries operate on intercalation principle with typical theoretical specific energy of 400-600 (Wh/Kg). There is great scientific interest in lithium-sulfur (Li-S) batteries as a possible successor of traditional Li-ion batteries because Li-S holds the potential of being a very powerful (1550 Wh/kg theoretical specific energy) yet very cost-efficient battery (due the abundance and inexpensiveness of sulfur). However, one major problem in Li-S battery research is the polysulfide “shuttle phenomenon”, which is the shuttling of polysulfide species due to the dissolution of sulfide from the …

Citizen Science Sensor Development - Smap | Soil Moisture Active Passive, Hagop Hovhannesian

STAR Program Research Presentations

“Detailed monitoring of soil moisture provides a view of how our whole Earth system works.”

The Soil Moisture Active Passive (SMAP) satellite mission was launched in January 2015; its main purpose is to acquire global measurements of soil moisture. SMAP partnered with the GLOBE program (Global Learning and Observations to Benefit the Environment), which is an international program where students collect environmental variables in a scientifically methodical way. SMAP readings and maps have various uses in various fields, which include monitoring drought, predicting floods, assisting in crop productivity, and linking water, energy and carbon cycles. The goal of this project …

Variations In Atmospheric 13c/14c Ratios Within A Radiocarbon Preparatory Lab And Implications For Ams Measurements, Kimberly Arias, Alexandra Hedgpeth, Karis Mcfarlane

STAR Program Research Presentations

At CAMS, we focus on measuring carbon isotopes (12/13/14C) for a variety of applications. High precision radiocarbon AMS measurements are used for measuring atmospheric radiocarbon. The problem with performing high precision radiocarbon AMS measurements is that there’s almost always background contamination introduced during preparation for the AMS. For graphite preparation, dry ice is used in an isopropyl-dry ice mixture to condense H2O in the CO2 extraction and reduction lines. Dry ice is composed of 12/13C and releases carbon into the atmosphere as it sublimes. The dry ice for preparation is held in containers inside and outside the lab. We believe …

Calculating The Energy Barriers Required To Join Metal-Organic Framework Synthesis Intermediates With Non-Equilibrium Molecular Simulation, Marcus A. Tubbs, David Cantu, Roger Rousseau, Vassiliki-Alexandra Glezakou

STAR Program Research Presentations

Metal organic frameworks are synthetic porous materials with great capacity for adsorption of carbon dioxide and methane. They chemically appear as a chain-link fence with nodes of metal connected by organic linkers. The pores between the nodes define the characteristics of the material, allowing gas particles of specific size to pass through while blocking larger particulates. While there has been success in synthesizing small amounts of metal organic frameworks, the mechanistic details behind their assembly remain unknown. Understanding the synthesis mechanism is necessary to understand the kinetics involved and be able to produce this useful material on an industrial scale. …

Using In Situ Liquid Single Photon Ionization Mass Spectrometry (Spi-Ms) To Probe Lithium Polysulfide Electrolyte In Motion, Aala M. Al Hasan, Jiachao Yu, Juan Yao, Vijayakumar Murugesan, Manjula Nandasiri, Xiao-Ying Yu

STAR Program Research Presentations

The solid-liquid (s-l) interface is the most common interface encountered in electrochemical systems. The s-l interface has wide applications in energy storage, catalysis, and material sciences. In situ studies of chemical reactions taking place on the s-l interfaces can further our understanding of electron transfer and link to real-world device functions under challenging conditions. Direct probing of the solid electrode and liquid electrolyte interface has been realized using a vacuum compatible electrochemical microfluidic reactor, system for analysis at the liquid vacuum interface (SALVI) with time-of-flight secondary ion mass spectrometry (ToF-SIMS). Most recently, the electrochemical version of SALVI was integrated to …

Reverse-Engineering The Brain: The Parts Are As Complex As The Whole., Jens G. Pohl

Collaborative Agent Design (CAD) Research Center

The purpose of this paper is to review the current state of neuroscience research with a focus on what has been achieved to date in unraveling the mysteries of brain operations, major research initiatives, fundamental challenges, and potentially realizable objectives. General research approaches aimed at constructing a wiring diagram of the brain (i.e., connectome), determining how the brain encodes and computes information, and whole brain simulation attempts are reviewed in terms of strategies employed and difficulties encountered. While promising advances have been made during the past 50 years due to electron microscopy, the development of new experimental methods, and the …

Environmental And Economic Implications Of Alternative Cruise Ship Pathways In Bermuda, Sarah E. Lester, Crow White, Kevin Mayall, Ryan K. Walter

Physics

As the cruise ship industry moves towards ever larger vessels, many tourist destinations are faced with dilemmas about how to accommodate the latest generation of ships, which require deeper and wider shipping pathways. The location of nearshore shipping channels traveled by cruise ships has important environmental and economic implications, as dredging larger lanes damages habitat, ship traffic produces sediment plumes that can smother adjacent sensitive habitats (e.g., coral reefs, seagrass beds), and dredging costs vary spatially. These environmental and economic costs should ideally be evaluated in the context of projected benefits from increased tourism. To inform decision-making on cruise ship …