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Articles 1 - 14 of 14
Full-Text Articles in Physics
Genealogical Vs Phylogenetic Mutation Rates: Answering A Challenge, Robert Carter
Genealogical Vs Phylogenetic Mutation Rates: Answering A Challenge, Robert Carter
Proceedings of the International Conference on Creationism
There is a discrepancy between the mutation rate we can measure today and the rate at which evolution is supposed to have proceeded. The former is sometimes called the genealogical mutation rate, for it is obtained by comparing individuals whom we know to be related. The latter is sometimes called the phylogenetic mutation rate. It is calculated by counting the fixed differences between two species and dividing by the estimated time since their common ancestor. Genealogical mutation rates are generally several orders of magnitude faster than phylogenetic estimates. This causes problems for the evolutionary model. For example, using the genealogical …
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 …
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 …
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.
Table Of Contents
Journal of the South Carolina Academy of Science
No abstract provided.
Improvements To Isru For Rocket Fuel Generation, Justin Sharp
Improvements To Isru For Rocket Fuel Generation, Justin Sharp
James Madison Undergraduate Research Journal (JMURJ)
The development of efficient in-situ resource utilization (ISRU) technologies is crucial for the establishment of an extraterrestrial, self-sustaining colony. The generation of rocket fuel at potential colony locations is necessary to provide the transportation of people and cargo to and from these locations.Three processes are discussed for the improvement of ISRU methods to generate rocket fuel: electrolysis and electrochemical improvements to the process of crude fuel production, physical and chemical methods for separation of gaseous H2 and O2, and materials and cryogenics engineering for storage and transportation of liquid hydrogen (LH2) and liquid oxygen (LOX). Storage and transportation of cryogenics …