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Articles 1 - 30 of 108
Full-Text Articles in Physical Sciences and Mathematics
Development Of A Particle-In-Cell/Monte Carlo Simulation For Weakly Ionized Plasmas, Xiaochuan (Chloe) Zheng, James Doyle
Development Of A Particle-In-Cell/Monte Carlo Simulation For Weakly Ionized Plasmas, Xiaochuan (Chloe) Zheng, James Doyle
Macalester Journal of Physics and Astronomy
A plasma is a gaseous system that contains large numbers of electrons and ions that are subject to forces produced by electric and magnetic fields. Weakly ionized plasmas, where the plasma density is much lower than the background gas density, are common in laboratory, atmospheric, and astrophysical situations. Theoretical calculations of plasma properties are challenging due to the complexity of the differential equations used to characterize fundamental physics. Particle-in-cell (PIC) simulations bypass the mathematical difficulties associated with analytic models, at the expense of more complex and time-consuming computer calculations. In this work we developed a one dimensional PIC simulation of …
Tools For Refining The Baryonic Tully-Fisher Relation, Ezra D. Wolf
Tools For Refining The Baryonic Tully-Fisher Relation, Ezra D. Wolf
Macalester Journal of Physics and Astronomy
This paper discusses the development of tools for galactic photometry using wise, and for reduction and analysis of 21cm galaxy spectra. These Python-based tools can then be applied to selected data in order to refine the Baryonic Tully-Fisher Relation. This relation, between baryonic mass and rotational velocity of a galaxy, proves useful for extragalactic research, particularly in calculating redshift-independent distances. While these tools could be further improved, they provide a robust process for calculation of particular galaxy characteristics.
Hydrosphere: Modeling The Planetary Structure Of Ocean Planets And Icy Moons, Karlee R. Taylor
Hydrosphere: Modeling The Planetary Structure Of Ocean Planets And Icy Moons, Karlee R. Taylor
Macalester Journal of Physics and Astronomy
In recent years, “water worlds” have become increasingly of interest to astrobiologists due to their high potential for habitability, as the large amount water on their surfaces is not only necessary for life, but also promises long-term climatic stability. However, also necessary for life is the exchange of chemical compounds between the geosphere and the hydrosphere - something which may be ob- structed by the presence of high pressure ices on these ocean planets and icy moons. In order to explore the habitability of bodies with various surface temperatures, water masses, and core radii, this project develops a model of …
From Experiment To Theory: Investigate The Effect Of Pump Beam Size On Photovoltaic Material Behavior, Dengyu Tu
Macalester Journal of Physics and Astronomy
In orde to investigate the effect of the pump beam size on an ultrafast conductivity measurement experiment, an experiment using Femto XL-500 laser and a simulation using Mathematica were performed. From the experiment data, we found that as the size of the pump beam decreases beyond certain limit, the Drude model can not accurately predict the relationship between conductivity and frequency. In addition, the simulation results corroborate with the experiment result that there is a limit for the size of the pump beam.
Machine Learning Refinements To Metallicity-Dependent Isotopic Abundances, Haoxuan Sun
Machine Learning Refinements To Metallicity-Dependent Isotopic Abundances, Haoxuan Sun
Macalester Journal of Physics and Astronomy
The project aims to use machine learning algorithms to fit the free parameters of an isotopic scaling model to elemental observations. The processes considered are massive star nucleosynthesis, Type Ia SNe, the s-process, the r-process, and p-isotope production. The analysis on the successful fits seeks to minimize the reduced chi squared between the model and the data. Based upon the successful refinement of the isotopic parameterized scaling model, a table providing the 287 stable isotopic abundances as a function of metallicity, separated into astrophysical processes, is useful for identifying the chemical history of them. The table provides a complete averaged …
Machine Learning Applications For Materials Science: Predicting Properties Of Two-Dimensional Magnetic Materials, Paige Stevenson
Machine Learning Applications For Materials Science: Predicting Properties Of Two-Dimensional Magnetic Materials, Paige Stevenson
Macalester Journal of Physics and Astronomy
We trained successful neural networks to predict the formation energy and magnetic moment of 2-dimensional ferromagnetic materials of similar structure to Cr2Ge2Te6. We collect elemental data on materials with known and unknown properties from easily accessible sources to screen for viable materials for use in future research. Random forest regressors were used to identify the most important predictors of our target qualities, which perform better on predictions of formation energy than magnetic moment. We predict the properties of 1225 materials that are candidates for further research in two-dimensional magnetism and identify several potential sources of error in our models that …
Measuring The Pulse Duration Of A Femtosecond Laser Using Intensity Autocorrelation, Ross N. Relic
Measuring The Pulse Duration Of A Femtosecond Laser Using Intensity Autocorrelation, Ross N. Relic
Macalester Journal of Physics and Astronomy
In this experiment, an intensity autocorrelator is set up in order to measure the pulse duration of a passively mode-locked Titanium-Sapphire laser with a power of 267mW producing femtosecond pulses. Then this measurement, as well as a measurement of the laser’s spectrum, is used to test the Uncertainty Principle. Intensity autocorrelation is a well-established technique for measuring pulse duration, and is among the more intuitive techniques for this purpose, which is why it was selected for this experiment. The experimental setup was computerized. The delay of one half of the pulse was controlled by a motorized translation stage which was …
Fabricating Perovskite Solar Cells: Fabrication Guide For Limited Lab Capabilities, Erin F. S. Leary
Fabricating Perovskite Solar Cells: Fabrication Guide For Limited Lab Capabilities, Erin F. S. Leary
Macalester Journal of Physics and Astronomy
Within the realm of emerging photovoltaics, Perovskite cells are one of the most intriguing technologies. Within a little over a decade, Perovskite solar cells have rivaled the efficiencies of traditional silicon solar cells and strongly outpaced other emerging photovoltaic technologies. This paper aims to show a fabrication guide for creating Perovskite solar cells in a limited lab setting. The fabrication guide created structures with strong physical reliability, but limited electrical reliability. More research is needed to ensure greater reliability and proper electrical function.
Solar Radio Bursts —Deployable Low-Band Ionosphere And Transients Experiment (Dlite) Arrays, Jonathan M. Kazor, Jason Kooi
Solar Radio Bursts —Deployable Low-Band Ionosphere And Transients Experiment (Dlite) Arrays, Jonathan M. Kazor, Jason Kooi
Macalester Journal of Physics and Astronomy
Solar radio bursts, phenomenon that often accompany CME, solar flares and other solar events, can be detected on earth and used in the prediction of solar weather that affects earth systems in several ways. As part of the NREIP Program supporting the Naval Research Laboratory, Remote Sensing Division, approximately ten interns participated in the analysis of data collected by DLITE and WAVES radio data. Data from DLITE is often used as a complement to data from WAVES due to differences in frequency range and resolution. The analysis helps to correlate the DLITE data with the data collected from other sources. …
Mapping The Tesseral Field Of Saturn, Aurora Hiveley
Mapping The Tesseral Field Of Saturn, Aurora Hiveley
Macalester Journal of Physics and Astronomy
Saturn's rotation rate is still uncertain, and while it is theorized to exhibit differential rotation much like Jupiter, this claim is somewhat disputed. By analyzing the properties of waves in the ring system of Saturn as measured by the Cassini spacecraft, we aim to provide observational evidence of this phenomenon. The results of wave analysis allow us to characterize the perturbers responsible for the production of these waves, which are believed to be mass anomalies in the interior of Saturn itself. By calculating the masses of these anomalies and attempting to pinpoint their locations inside of the planet, we provide …
Trinification With A Bi-Adjoint Higgs Field, Ross Ferguson
Trinification With A Bi-Adjoint Higgs Field, Ross Ferguson
Macalester Journal of Physics and Astronomy
In this paper, we propose a novel extension of the Standard Model of particle physics, based on the trinification gauge group $SU(3)_C \times SU(3)_L \times SU(3)_R$. Symmetry breaking is achieved using a bi-adjoint Higgs field (transforming under the left- and right-handed subgroups) along with a more conventional bi-triplet to ensure the correct breaking and pattern of fermion masses. To preserve a discrete $Z_2$ symmetry (T-parity), we also introduce a right-handed triplet to completely break trinification symmetry to the Standard Model. The minimization conditions and conditions for the boundedness of the potential for this model are calculated. Additionally, the Standard Model …
A High-Speed Portable Ground Heat Exchanger Model For Use In Various Energy Simulation Software, Ryan Davies, Matt Mitchell, Edwin Lee
A High-Speed Portable Ground Heat Exchanger Model For Use In Various Energy Simulation Software, Ryan Davies, Matt Mitchell, Edwin Lee
Macalester Journal of Physics and Astronomy
A portable component model (PCM) of a ground source heat pump system was developed and used as a test case in the creating of a PCM development framework. By developing this framework, new building energy simulation models will be able to be easily integrated into existing simulation software such as EnergyPlus and the Modelica Buildings Library. Our model uses a time responsive g-function and numerical methods to simulate ground source heat pumps for single time steps as well as long time scales. We validated our model against GHESim and GLHEPro and found that our model agrees with these two standards …
Extension Of The Lux-Zeplin Nr Background To 600 Phd, Jackson Codd
Extension Of The Lux-Zeplin Nr Background To 600 Phd, Jackson Codd
Macalester Journal of Physics and Astronomy
In June 2022, the LUX-ZEPLIN collaboration released its first results, with the
most precise measurements of any direct dark matter detector. The findings were
calculated using the expected spin-independent WIMP-nucleon interaction model,
which would result in small energies deposited in the detector. Therefore, the
background of non-dark interactions was calculated for events with S1 areas up to
80 phd (Aalbers et al. 2022). In order to increase the sensitivity to high energy
WIMP-nucleon interaction events, as predicted by other models, we extended the
non-dark NR background to events with S1 areas of up to 600 phd. We found a
large …
Adding Classical Novae Contribution To The Isotopic Scaling Model, Mengxi Chen
Adding Classical Novae Contribution To The Isotopic Scaling Model, Mengxi Chen
Macalester Journal of Physics and Astronomy
The Isotopic Scaling model(West & Heger, 2013) provides a complete average isotopic decomposition for our Milky Way as a function of metallicity and it requires an initial Solar Abundance Decomposition as a starting point. The previous Solar Abundance decomposition work is not perfect(West & Heger, 2013), since Classical Novae abundances are ignored. My research intends to improve the current solar abundance decomposition by adding Classical Novae Abundance contribution, then to update the Isotopic Scaling model.
Effectiveness Of Different Materials As Catalysts For Alkaline Water Electrolysis, Lance T. Bartol, James Doyle
Effectiveness Of Different Materials As Catalysts For Alkaline Water Electrolysis, Lance T. Bartol, James Doyle
Macalester Journal of Physics and Astronomy
We tested the catalytic properties of various nickel and molybdenum electrodes as potential replacements for platinum for usage in alkaline water electrolysis. After initial tests found molybdenum-based electrodes to be significantly more effective than nickel electrodes, we moved to calculate overpotentials. We found nickel electrode overpotentials at ± 10 mA current to be 939 and -960 mV. Conversely, molybdenum electrode overpotentials at the same currents were 244 and -681 mV respectively. While still significantly higher than overpotentials for platinum, these results indicate that, with more testing, molybdenum-based electrodes could eventually emerge as a cheaper, more abundant alternative to platinum electrodes.
Smart Grid Control: Demand Side Management In Household Refrigerators As A Tool For Load Shifting, Anogh Utkalika Zaman, James Doyle
Smart Grid Control: Demand Side Management In Household Refrigerators As A Tool For Load Shifting, Anogh Utkalika Zaman, James Doyle
Macalester Journal of Physics and Astronomy
With improved supply of renewable sources of energy the focus has shifted away from simply producing clean energy to efficient consumption of energy. Until cheaper methods of energy storage are developed, Demand Side Management (DSM) is the best option for maximising energy efficiency. This paper proposes a method of turning regular refrigerators into smart demand response fridges. First, we develop an algorithm that accounts for small fluctuations in price and switches the device for optimal performance and lowered running cost. Then, we use longer price fluctuations to predict suitable times for pre-cooling and investigate the reduction in price as a …
Twisting Lasers With The Faraday Effect, Harrison Werrell
Twisting Lasers With The Faraday Effect, Harrison Werrell
Macalester Journal of Physics and Astronomy
Our objective with this project was to create a system and procedure to quantify the magnetization of a material with polarized light by using the Faraday Effect, where the light is rotated according to the magnetization. This type of system has seen use in technologies such as magneto-optical drives and optical isolators, and is part of the study of optical materials, along with the similar MagnetoOptical Kerr Effect. Our system, specifically, is intended to be used as part of an advanced Physics Lab in the future. It uses an electromagnet to magnetize a sample, and a laser to observe the …
Electrical Analysis Of A Pem Electrolysis Cell, Joey Wehrley, James Doyle
Electrical Analysis Of A Pem Electrolysis Cell, Joey Wehrley, James Doyle
Macalester Journal of Physics and Astronomy
Polymer Electrolyte Membrane (PEM) electrolysis is a form of electrolysis that is heavily used in commercial capacities. It functions by using a membrane and an electric charge in order to perform electrolysis water, splitting it into its component parts - Hydrogen and Oxygen. These parts can then be used in a number of different applications, including reversing the electrolysis process to regenerate some energy in the form of electricity. During this experiment, multiple currents were run through a PEM cell, and voltages across the membrane were measured. It was found that a standard R/C charging model can be fit to …
The Interaction Of Topological Defects In Anisotropically-Elastic Nematic Liquid Crystals, Carter J. Swift
The Interaction Of Topological Defects In Anisotropically-Elastic Nematic Liquid Crystals, Carter J. Swift
Macalester Journal of Physics and Astronomy
Topological defects are very well understood so long as the medium in which they exist is isotropically-elastic. They lead to director fields which are easy to calculate and superpose linearly so that a system with any number of defects is analytically treatable. They also have an interaction which is simple in form and can be accurately described by the Peach-Koehler force. In an anisotropically-elastic medium, however, such defects are very poorly understood outside of the single-defect case which was solved by Dzyaloshinskii. In this project, numerical and approximate analytical techniques are applied in order to better understand the interaction between …
Neutrino Oscillations In The Presence Of A Magnetic Field, Chinhsan Sieng
Neutrino Oscillations In The Presence Of A Magnetic Field, Chinhsan Sieng
Macalester Journal of Physics and Astronomy
We calculate oscillation probabilities in the presence of an external magnetic field in a one-generation neutrino framework that includes both Majorana and Dirac mass terms. First, we write down the Euler-Lagrange equations and obtain a system of eight differential equations coupling together eight different neutrino states that can be distinguished by helicity, chirality, and particle/antiparticle-ness. We then solve this system of differential equations in various special cases, exhibiting different types of oscillations. When the magnetic field is in the direction of momentum, there are only four oscillation channels as helicity flip is forbidden. We observe that chirality flips are suppressed …
The Impact Of Initial Abundances On Modeling The Weak S-Process, Lev S. Serxner
The Impact Of Initial Abundances On Modeling The Weak S-Process, Lev S. Serxner
Macalester Journal of Physics and Astronomy
No abstract provided.
The Survey Of Hi In Extremely Low-Mass Dwarfs: New Results From Vla Imaging, Francesco Pecere, John M. Cannon, Damen Beverlin, Jackson Codd
The Survey Of Hi In Extremely Low-Mass Dwarfs: New Results From Vla Imaging, Francesco Pecere, John M. Cannon, Damen Beverlin, Jackson Codd
Macalester Journal of Physics and Astronomy
We present new HI spectral line imaging of 19 galaxies in the “Survey of HI in Extremely Low-mass Dwarfs” (SHIELD) acquired for Large Program VLA/ 20A-330. Using the National Radio Astronomy Observatory’s Karl G. Jansky Very Large Array (VLA) in the C configuration, we produce images of the neutral interstellar medium (HI) on angular scales of 15 to 20 arcseconds (corresponding to physical resolutions of 200 to 1100 parsecs). The three-dimensional cubes probe the morphology and kinematics of the gas at a range of spatial and spectral resolutions. The cubes were collapsed to produce two-dimensional moment maps (representing HI mass …
Hunting For Fast Radio Bursts From Messier 82: Exploring The Frb--Magnetar Connection, Susie Paine
Hunting For Fast Radio Bursts From Messier 82: Exploring The Frb--Magnetar Connection, Susie Paine
Macalester Journal of Physics and Astronomy
Fast radio bursts (FRBs) are short-duration radio pulses of cosmological origin. Among the most common sources predicted to explain this phenomenon are bright pulses from a class of extremely highly magnetized neutron stars known as magnetars. In 2020, a Galactic magnetar produced an FRB-like burst, allowing researchers to constrain the Galactic magnetar burst rate. We assume that the magnetar burst rate scales with star formation rate and test an important prediction for similar bursts in nearby galaxies. Messier 82 (M82) has a star formation rate 40 times that of the Milky Way, implying that the magnetar burst rate would be …
Finite-Difference-Time-Domain Simulation Of Ultrafast Experiments, Alpha Ma
Finite-Difference-Time-Domain Simulation Of Ultrafast Experiments, Alpha Ma
Macalester Journal of Physics and Astronomy
The Finite-Difference-Time-Domain (FDTD) method is a numerical method that calculates electric fields or magnetic fields by interleaving them in space and time. Using a python package called “MEEP”, I was able to write optical simulations of ultrafast experiments, especially the Terahertz Pump-Probe experiments. The goal of this project was to use FDTD simulation to measure the transmission of an electro-magnetic pulse passing through a thin film of conducting material on a dielectric substrate in order to study the characteristic conductivity of potential solar cell materials.
Molecular Line Search In Archival Alma Imaging Of M87, Xueyi Li
Molecular Line Search In Archival Alma Imaging Of M87, Xueyi Li
Macalester Journal of Physics and Astronomy
We present a molecular line search in spectral imaging of the elliptical galaxy M87 using archival data from the Atacama Large Millimeter/sub-millimeter Array (ALMA). The primary goal of this project is to verify and characterize possible CO transition lines, which can be used for future studies to determine the dynamics of the system, or the mass of the supermassive black hole (BH) in the center of the galaxy. After performing extensive atmospheric modeling, we found that most of the absorption features have a corresponding atmospheric ozone transition, so it is unlikely that these features are either Galactic or extragalactic. We …
Lie Algebras And The Poincare Group, Jack Hempel Costello
Lie Algebras And The Poincare Group, Jack Hempel Costello
Macalester Journal of Physics and Astronomy
This paper will discuss my research with
Professor Tonnis ter Veldhuis on the Poincare Group
and other similar algebraic approaches based on the
Minkowski Metric. This paper will begin with an
introduction discussing group theory and expand on its
specific applications in theoretical physics.
Simulating Interactions Between Coronal Mass Ejections, Damen S. Beverlin, Tatiana Niembro
Simulating Interactions Between Coronal Mass Ejections, Damen S. Beverlin, Tatiana Niembro
Macalester Journal of Physics and Astronomy
Coronal mass ejections (CMEs) launch large amounts of plasma and magnetic fields into the interplanetary medium. Under the right initial conditions, this ejecta can reach Earth and cause issues with electronic devices. As such, we would like to have an accurate model that depicts how these CMEs propagate as they leave the sun. By using fluid dynamics and one-minute resolution in-situ solar wind data, we sought to simulate CME plasma propagation with analytical and numerical models. Because the interstellar medium contains other material and other events happen on the sun simultaneously, CMEs can interact with each other and other ejecta, …
Custom Calibration And Correction Of Photoemission Electron Microscope Images Using Graphene, Henry Bell
Custom Calibration And Correction Of Photoemission Electron Microscope Images Using Graphene, Henry Bell
Macalester Journal of Physics and Astronomy
The Photoemission Electron Microscope (PEEM) is a full-field electron microscope that utilizes the photoelectric effect to image a surface. Due to a spatial resolution on the order of 10 nanometers and its ability to image both the morphology of a surface and its band structure, it is a useful tool for understanding the properties of materials for use in electronic devices. To correct for random sample misalignment and the experimental frame of reference in the spectroscopy mode of the PEEM, the 3D dataset must be rotated in both the momentum and energy coordinates which requires pixel calibration and energy alignment. …
Knocking Down Nox: Examining The Effects Of Transportation Electrification On Urban Ozone Production In The South Coast Air Basin, Jason Beal
Macalester Journal of Physics and Astronomy
With last year’s commitment to all in-state sales of new passenger cars and trucks being zero-emission by 2035 (California Executive Order N-79-20), California is leading the charge for transportation electrification in the United States. Despite being at the forefront of climate change management and mitigation, California has some of the worst air quality in the nation. While primarily motivated by a desire to reduce carbon dioxide emissions and reliance on fossil fuels, transportation electrification will also have a significant impact on local air quality. The goal of this study is to quantify and qualify this impact in the context of …
Sampling Candidate Reionization Galaxies Using Spectral Energy Distribution Fitting, Nicholas J. Velikonja, Michael Rutkowski
Sampling Candidate Reionization Galaxies Using Spectral Energy Distribution Fitting, Nicholas J. Velikonja, Michael Rutkowski
Macalester Journal of Physics and Astronomy
The process of reionization is one of the major pieces of galaxy evolution which remain to be un- derstood. With new observational tools like JWST on the horizon, imaging reionization-era galaxies will soon be possible. However, because the ionizing radiation is absorbed by the neutral hydrogen it ionizes, observers need some other parameter by which to identify those galaxies capable of reionizing. The search for ionizing emission via related parameters is well underway, and has come up with some tentative correlations, yet a consistent indicator or set of indicators remains to be discovered. New data in the Low-Redshift Lyman Continuum …