Physics Commons^™

Investigation Of Student Understanding Of Representations Of Probability Concepts In Quantum Mechanics, William D. Riihiluoma

Electronic Theses and Dissertations

The ability to relate physical concepts and phenomena to multiple mathematical representations—and to move fluidly between these representations—is a critical outcome expected of physics instruction. In upper-division quantum mechanics, students must work with multiple symbolic notations, including some that they have not previously encountered. Thus, developing the ability to generate and translate expressions in these notations is of great importance, and the extent to which students can relate these expressions to physical quantities and phenomena is crucial to understand.

To investigate student understanding of the expressions used in these notations and the ways they relate, clinical think-aloud interviews were conducted …

Influence Of Platinum Nanoparticles On Ionic Transport And Hydrogen Reactivity Of Yttria-Stabilized Zirconia Thin Films, Firas Mahyob

Electronic Theses and Dissertations

Yttria-stabilized zirconia (YSZ) is a widely used ceramic material in solid oxide fuel cells, oxygen sensors, and sensing applications due to its high ionic conductivity, chemical inertness, and thermal stability. YSZ is promising active coating for use in miniaturized harsh environment wireless surface acoustic sensors to monitor gases such as H₂. Adding catalytic Pt nanoparticles can enhance gas reactivity and lead to associated film conductivity changes.

In this work, thin films with an (8% Y₂O₃ - 92% ZrO₂) composition were deposited onto piezoelectric langasite substrates using RF magnetron sputtering in Ar:O₂ - …

Horizon Content Knowledge And Its Integration Into Physics Education Research: Case Study Analysis On Physical Science And Physics Teachers, Trevor A. Robertson

Electronic Theses and Dissertations

Teachers focused on just one year of instruction may neglect what students need most– a coherent structure of learning across disciplines that advances students’ understanding. The topic of coherence has been a major motivator for education research, including investigations in student- teacher interactions, epistemological beliefs, and large-scale curricular reform. One framework of knowledge, horizon content knowledge (HCK), can aid in describing the knowledge a teacher needs to see beyond their own instruction and provide a coherent structure for students.

While horizon content knowledge exists in one of the most widely adopted teacher frameworks of knowledge in mathematics, mathematical knowledge for …

Remotely Sensed Assessment Of The Preferred Habitat Of Alexandrium Catenella In The Gulf Of Maine And The Bay Of Fundy, Andre F. Bucci

Electronic Theses and Dissertations

Harmful Algal Blooms (HABs) of the toxic dinoflagellate Alexandrium catenella are an annually recurring problem in the Gulf of Maine (GoM), resulting in risks to human health and substantial economic losses due to shellfish harvesting closures. The monitoring approaches in the region are restricted to real-time identification of the HABs events, when they are clearly underway and already causing deleterious effects to the environment. To fully function as an early warning system rather than an immediate response, monitoring strategies need to be focused on environmental conditions preceding A. catenella HABs. However, the current understanding of the preferred habitat for A. …

Measurement Of Airborne Radionuclides And Their Relation To Weather Patterns At Orono, Me, James W. Deaton

Electronic Theses and Dissertations

7Be and 210Pb activities were measured in air sampling filters collected at The University of Maine campus from 2014 to 2019. The activities of 7Be were in the range of 1.178-98.8 Bq, with an average value of 32.13 Bq. The activities of 210Pb were in the range of 0.091 to 13.64 Bq, and an average value of 3.029 Bq. The distributions of activity for both radionuclides are lognormal. Both 7Be and 210Pb show seasonal variation with maximum values in the summer and minimum values in the fall, and the 7Be/210Pb ratio shows a clear seasonal variation with maxima in the …

An Investigation Of Students' Use And Understanding Of Evaluation Strategies, Abolaji R. Akinyemi

Electronic Theses and Dissertations

One expected outcome of physics instruction is that students develop quantitative reasoning skills, including evaluation of problem solutions. To investigate students’ use of evaluation strategies, we developed and administered tasks prompting students to check the validity of a given expression. We collected written (N>673) and interview (N=31) data at the introductory, sophomore, and junior levels. Tasks were administered in three different physics contexts: the velocity of a block at the bottom of an incline with friction, the electric field due to three point charges of equal magnitude, and the final velocities of two masses in an elastic collision. Responses …

Application Of Machine Learning Techniques To Classify And Identify Galaxy Merger Events In The Candels Field, Alex Koch

Electronic Theses and Dissertations

Galaxy mergers are dynamic systems that offer us a glimpse into the evolution of the cosmos and the galaxies that constitute it. However, with the advent of large astronomical surveys, it is becoming increasingly difficult to rely on humans to classify the vast number of astronomical images collected every year and find the images that capture these systems. In recent years, researchers have increasingly relied on machine learning and computer vision classifiers, and while these techniques have proven useful for classifying broad galaxy morphologies, they have struggled to identify galaxy mergers. A random forest classifier was applied to a subset …

Hydrodynamic Impacts Of Expanding Aquaculture, Zhilong Liu

Electronic Theses and Dissertations

Climate change may potentially change aquatic systems and bring certain risks for aquaculture development. Understanding interactions between aquaculture and the environment helps to ensure aquaculture expansion is sustainable in the future. It is critical to determine how farms influence tidal flow patterns, turbulence, mixing and material transport in estuaries. This research aims to determine the flow response of an oyster farm, predict how expanding farms and farm placement will alter estuarine dynamics, and understand how the design of a farm influences material transport.

The hydrodynamic response of a floating oyster aquaculture farm in a low inflow estuary (the Damariscotta River …

Toward Improving Understanding Of The Structure And Biophysics Of Glycosaminoglycans, Elizabeth K. Whitmore

Electronic Theses and Dissertations

Glycosaminoglycans (GAGs) are the linear carbohydrate components of proteoglycans (PGs) that mediate PG bioactivities, including signal transduction, tissue morphogenesis, and matrix assembly. To understand GAG function, it is important to understand GAG structure and biophysics at atomic resolution. This is a challenge for existing experimental and computational methods because GAGs are heterogeneous, conformationally complex, and polydisperse, containing up to 200 monosaccharides. Molecular dynamics (MD) simulations come close to overcoming this challenge but are only feasible for short GAG polymers. To address this problem, we developed an algorithm that applies conformations from unbiased all-atom explicit-solvent MD simulations of short GAG polymers …

Live Cell Super-Resolution Microscopy Quanitifies An Interaction Between Influenza Hemagglutinin And Phosphatidylinositol 4,5-Bisphosphate, Jaqulin N. Wallace

Electronic Theses and Dissertations

Influenza virus, colloquially known as the flu, is an acute respiratory disease that infects several millions of individuals each year in the U.S. and kills tens of thousands of those infected. Yearly viral vaccines are widely available, however, due to the virus’s high mutation rate, their efficacy varies greatly. Due to the variability in vaccine efficiency against seasonal influenza, and the potential for even more pathogenic versions of influenza to emerge at any time, there is a high demand for a universal treatment option.

Influenza virus hijacks a variety of host cell components in order to replicate. The glycoprotein hemagglutinin …

Biophysical And Stable Isotopic Profiles Of The Salmon Louse Lepeophtheirus Salmonis (Krøyer, 1837), Emma Taccardi

Electronic Theses and Dissertations

The salmon louse Lepeophtheirus salmonis is a parasitic copepod that infects wild and farmed salmonids throughout the northern hemisphere. L. salmonis represents the largest economic hurdle of the Atlantic salmon (Salmo salar) industry, with an estimated annual cost of nearly $1 billion globally due to production losses and anti-parasitic control measures. Salmon farming in Maine has existed for decades and is a critical economic driver, yet the region is underrepresented in global sea lice research. The aim of this work was to examine parasites in the context of animal trophic transfer and characterize physiological condition by quantifying the …

Understanding The Magnetic Properties Of Ii-Vi Semiconductor Nanocrystals, Alex Khammang

Electronic Theses and Dissertations

Semiconductor nanocrystals (NC) are well known for their unique size tunable optical properties making them suitable candidates for devices such as light emitting diodes (LEDs), solar cells, and cellular labels. II-VI semiconductors in the bulk form behave diamagnetically, but can inherit paramagnetic (PM) or ferromagnetic (FM) properties at the nanoscale. Reports suggest that the emergence of weak PM or FM behavior in undoped NCs are attributed to the increased surface to volume ratio compared for NCs. Traditionally, these NCs only obtain magnetic properties after doping with certain transition metals, such as Co, Mn, or Fe. Many mechanisms have been proposed …

A Numerical Survey Of Multi-Planet Systems’ Inclination Excitation And Survival Under The Influence Of An Oblate, Tilted Star, Kathleen M T Schultz

Electronic Theses and Dissertations

Among the many exciting and thought-provoking discoveries facilitated by the Kepler telescope, one of the most puzzling is the very large proportion of systems with only a single transiting planet in them, relative to the number of systems with multiple transiting planets. Given that most of these multis are close together and have low mutual inclinations, and that planetary systems tend to form in such a configuration, the next logical step is to guess that at least some of the singles are part of multi-planet systems with large mutual inclinations between planets, excited by some other object’s gravitational perturbations. A …

Quantification Of Interactions Between Influenza Hemagglutinin And Host Cell Phosphoinositides By Super-Resolution Microscopy, Matthew T. Parent

Electronic Theses and Dissertations

The influenza viral membrane protein hemagglutinin (HA) forms dense nanoscale clusters on host cell plasma membranes (PM), but the mechanisms that direct HA clustering are not well understood. Previous studies have observed HA associated with actin rich regions of the PM, but there are no known direct interactions between HA and actin. Phosphatidylinositol 4,5-biphosphate (PIP2) is a signaling lipid in the PM which can regulate the actin cytoskeleton, and actin comets initiated by PIP2 are known to be exploited by HA to reach the PM of infected cells. PIP2 is also used by other viruses, such as HIV and Ebola, …

Phytoplankton Community Composition In The Surface Ocean: Methods For Detection Using Optical Measurements, Pigment Concentrations, And Flow Cytometry, Alison P. Chase

Electronic Theses and Dissertations

Phytoplankton are microscopic photoautotrophs living in the surface ocean waters and help support all life on earth via photosynthetic production of oxygen. Thousands of species make up the bulk phytoplankton community, and the spatial and temporal distribution of different types of phytoplankton has relevance for many ocean ecosystem questions including marine food web dynamics, and carbon flux and sequestration. Methods to detect phytoplankton community composition (PCC) on the vast scale of the global ocean require estimates of PCC from remote platforms, namely earth-observing satellites. The use of satellite data to observe and interpret PCC in the surface ocean requires significant …

Uav 6dof Simulation And Kalman Filter For Localizing Radioactive Sources, John G. Goulet

Electronic Theses and Dissertations

Unmanned Aerial Vehicles (UAVs) expand the available mission-space for a wide range of budgets. Using MATLAB, this project has developed a six degree of freedom (6DOF) simulation of UAV flight, an Extended Kalman Filter (EKF), and an algorithm for localizing radioactive sources using low-cost hardware. The EKF uses simulated low-cost instruments in an effort to estimate the UAV state throughout simulated flight.

The 6DOF simulates aerodynamics, physics, and controls throughout the flight and provides outputs for each time step. Additionally, the 6DOF simulation offers the ability to control UAV flight via preset waypoints or in realtime via keyboard input.

Using …

New Methodologies For Examining And Supporting Student Reasoning In Physics, John C. Speirs

Electronic Theses and Dissertations

Learning how to reason productively is an essential goal of an undergraduate education in any STEM-related discipline. Many non-physics STEM majors are required to take introductory physics as part of their undergraduate programs. While certain physics concepts and principles may be of use to these students in their future academic careers and beyond, many will not. Rather, it is often expected that the most valuable and longlasting learning outcomes from a physics course will be a repertoire of problem-solving strategies, a familiarity with mathematizing real-world situations, and the development of a strong set of qualitative inferential reasoning skills.

For more …

Using Question Variations To Access Alternate Student Thinking About The Same Physical Situations, Jeffrey Mathis Hawkins

Electronic Theses and Dissertations

Assessing students’ understanding of physics is a critical element for improving physics education. This dissertation presents and demonstrates a method to better assess student understanding of physics by varying the types of questions asked of students. The method presented herein, which is based on the Specific Difficulties and Resources frameworks, involves modifying the task students are asked to complete when analyzing the physics of a particular physical situation. Creating question variations that ask students to address a particular correct or incorrect outcome of the physical situation, eliminate an incorrect outcome, or justify a correct outcome provided to them can provide …

450degree C Aln Thin Film Growth On Nitrided C-Plane Sapphire Substrates, Roger Eastman Feeley

Electronic Theses and Dissertations

Low temperature (LT) growth of strongly textured AlN by molecular beam epitaxy (MBE) has not been extensively investigated. The low mobility of Al adatoms provides a challenge for growth of AlN at low temperatures (<600 >°C). Consequently, AlN growth by MBE is typically at temperatures >700 °C. Growth at these temperatures can limit the selection of substrates and materials to grow with the AlN. Highly oriented, LT AlN thin films (<50 >nm) were grown on c-­‐plane sapphire, using an interrupted growth procedure. Films were grown by periodically interrupting the Al flux with a nitridation. This two-­‐step cycle was repeated until …

Application Of Silicon Nanohair Textured P-N Junctions In A Photovoltaic Device, Michael Small

Electronic Theses and Dissertations

The goal of this project is to design and develop a fabrication process for a silicon photovoltaic device which incorporates a nanohair textured p-n junction. The silicon nanowires are etched into a silicon wafer, comprising an epitaxial p-layer on n-substrate, via metal-assisted chemical etching (MACE). The resulting nanowires contain p-n junctions that lie along the length of the vertical nanowires. This construct has the potential to increase the optical bandwidth of a silicon photovoltaic device by allowing a greater amount of short wavelength light to reach the junction. In addition, the MACE method of nanofabrication has the potential for decreasing …

Three-Dimensional Bedrock Channel Evolution With Smoothed Particle Hydrodynamics, Nick Richmond

Electronic Theses and Dissertations

Bedrock channels are responsible for balancing and communicating tectonic and climatic signals across landscapes, but it is difficult and dangerous to observe and measure the flows responsible for removing weakly-attached blocks of bedrock from the channel boundary. Consequently, quantitative descriptions of the dynamics of bedrock removal are scarce. Detailed numerical simulation of violent flows in three dimensions has been historically challenging due to technological limitations, but advances in computational fluid dynamics aided by high-performance computing have made it practical to generate approximate solutions to the governing equations of fluid dynamics. From these numerical solutions we gain detailed knowledge of the …

Investigating Student Understanding Of Vector Calculus In Upper-Division Electricity And Magnetism: Construction And Determination Of Differential Element In Non-Cartesian Coordinate Systems, Benjamin Schermerhorn

Electronic Theses and Dissertations

Differential length, area, and volume elements appear ubiquitously over the course of upper-division electricity and magnetism (E&M), used to sum the effects of or determine expressions for electric or magnetic fields. Given the plethora of tasks with spherical and cylindrical symmetry, non-Cartesian coordinates are commonly used, which include scaling factors as coefficients for the differential terms to account for the curvature of space. Furthermore, the application to vector fields means differential lengths and areas are vector quantities. So far, little of the education research in E&M has explored student understanding and construction of the non-Cartesian differential elements used in applications …

Microwave Acoustic Saw Resonators For Stable High-Temperature Harsh-Environment Static And Dynamic Strain Sensing Applications, Anin K. Maskay

Electronic Theses and Dissertations

High-temperature, harsh-environment static and dynamic strain sensors are needed for industrial process monitoring and control, fault detection, structural health monitoring in power plant environments, steel and refractory material manufacturing, aerospace, and defense applications. Sensor operation in the aforementioned extreme environments require robust devices capable of sustaining the targeted high temperatures, while maintaining a stable sensor response. Current technologies face challenges regarding device or system size, complexity, operational temperature, or stability.

Surface acoustic wave (SAW) sensor technology using high temperature capable piezoelectric substrates and thin film technology has favorable properties such as robustness; miniature size; capability of mass production; reduced installation …

Surface Reaction And Diffusion Kinetics In Semiconducting Metal Oxide Film Gas Sensors, Aravind Reghu

Electronic Theses and Dissertations

Chemiresistive metal oxide gas sensors based on materials such as SnO₂, ZnO, and TiO₂, have been investigated extensively by many researchers for a wide range of applications. The band bending model, based on the surface chemistry of highly reactive ionosorbed species (O₂^- or O^-) and the semiconducting material properties of SnO₂, TiO₂ and ZnO, adequately predicts the dependence of the change in sensor conductivity (Δσ) as a function of target gas pressure and temperature. However, the band bending model is not applicable to gas sensors based on reducible oxides …

Echoes Of The Past: The Effect Of Background Experience On Far Transfer, Graham H. Hummel-Hall

Electronic Theses and Dissertations

Far transfer is the application of knowledge learned in one setting to a problem in a very different setting. This multi-method study looked at far transfer in humans and whether it could be facilitated, inhibited, or remain unaffected by the number of courses or years a student at a university spent learning about the subject matter of the knowledge being transferred. Through quantitative and qualitative analysis of pretest and post-test data from an introductory undergraduate earth science course, I found that students with more physical science background experience more frequently engaged in successful and accurate transfer of physics information to …

Transformation Of Nonlinear Waves In The Presence Of Wind, Current, And Vegetation, Haifei Chen

Electronic Theses and Dissertations

Accurate prediction of extreme wave events is crucial for the safe maritime activities and offshore operations. Improved knowledge of wave dissipation mechanisms due to breaking and vegetation leads to accurate wave forecast, protecting life and property along the coast. The scope of the thesis is to examine the wave transformations in the presence of wind, current, and vegetation, using a two-phase flow solver based on the open-source platform OpenFOAM. The Reynolds-Averaged Navier-Stokes (RANS) equations are coupled with a Volume of Fluid (VOF) surface capturing scheme and a turbulence closure model. This RANS-VOF model is adapted to develop a numerical wind-wave-current …

Integrated Environment And Proximity Sensing For Uav Applications, Shawn S. Brackett

Electronic Theses and Dissertations

As Unmanned Aerial Vehicle (UAV), or “drone” applications expand, new methods for sensing, navigating and avoiding obstacles need to be developed. The project applies an Extended Kalman Filter (EKF) to a simulated quadcopter vehicle though Matlab in order to estimate not only the vehicle state but the world state around the vehicle. The EKF integrates multiple sensor readings from range sensors, IMU sensors, and radiation sensors and combines this information to optimize state estimates. The result is an estimated world map to be used in vehicle navigation and obstacle avoidance.

The simulation handles the physics behind the vehicle flight. As …

Using Hydroacoustics To Investigate Biological Responses In Fish Abundance To Restoration Efforts In The Penobscot River, Maine, Constantin C. Scherelis

Electronic Theses and Dissertations

Spatiotemporal advantages linked to hydroacoustic sampling techniques have caused a surge in the use of these techniques for fisheries monitoring studies applied over long periods of time in marine systems. Dynamic physical conditions such as tidal height, boat traffic, floating debris, and suspended particle concentrations result in unwanted noise signatures that vary in intensity and location within a hydroacoustic beam over time and can be mixed with the acoustic returns from intended targets (e.g., fish). Typical processing filters applied over long term datasets to minimize noise and maximize signals do not address spatiotemporal fluctuations of noise in dynamic systems. We …

Basic Vision Research With Clinical Applications And Science Education Assessments, Andrew Wilson

Electronic Theses and Dissertations

Visual Acuity (VA) examinations are one of the most commonly conducted medical assessment throughout the world. Recent advances in computer technology allows for new forms of visual assessment to be conducted. In Part I of this thesis I demonstrate the capability of an automated computer program named VISION to assess human visual acuities. Different color combinations of an object against a background emitted from a computer screen are used to examine a variety of human color vision acuities. Results indicated a large difference in acuity scores between human subjects tested with these different color combinations. A single human subject exhibits …

A Study In Cross-Beam Polarization Fluorescence Photoactivation Localization Microscopy On Dendra2-Hemagluttinin In Fixed Nih3t3 Cells, Matthew M. Valles

Electronic Theses and Dissertations

Fluorescence microscopy is popular for its noninvasive properties and its use in imaging multiple species, simultaneously. Furthermore, superresolution fluorescence microscopy (SRFLM) utilizes photoswitchable proteins to improve the lateral resolution of conventional fluorescence microscopy by an order of magnitude. There is little work conducted on the study of excitation laser polarizations and their effect on the number of localizations as well as the brightness of molecules. This thesis attempts to study the effect of excitation wavelength polarization on the number of localizations and the brightness of molecules by comparing two orientations of circularly-polarized, excitation lasers. The first type of orientation involves …