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Happy Birthday Floral Card From Dr. Salterwhite And Family To Eartha White

Eartha M. M. White Textual Material

Card: Card sent with flowers for a "Happy Birthday" from Dr. Salterwhite and family. Flowers from Thomas - Florist, 23 W. Monroe St., Jacksonville, Florida. Undated.

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Survey Of Possible Magnetic Field Sources Around The Intragroup Medium Of Ngc 2563, Edward A. Wallace, Anna Williams

Macalester Journal of Physics and Astronomy

The origin and evolution of magnetic fields in space is an ongoing mystery in astronomy. Previous work has concluded the existence of magnetic fields in galaxy clusters, and to build an evolutionary model, the motivation behind this project is to determine how these magnetic fields form. In order to answer this question, we want to search for magnetic fields in galaxy group NGC 2563. To do this, our project determines the contribution to observed rotation measures of the galaxy group that come from the Milky Way and from the sources themselves.

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Modelling Of The Overcontact Eclipsing Binary V826 Aur, Kalev T. Murray-Rouse, John M. Cannon, Anna Williams, Wes Tobin

Macalester Journal of Physics and Astronomy

We present a model of the eclipsing binary system V826 Aur using differential photometric data from the Robert L. Mutel Telescope (RLMT) at the Winer Observatory in Sonoita, Arizona. The calculated time of superconjunction was found to be 60648.7658534 and the period was 0.361701 d. These values were used to generate a best-fit model of the eclipsing binary with the PHOEBE program. The best-fit modelled parameters were found to be: mass ratio (𝑞) is equal to 2.769, the inclination (𝑖) is equal to 80.45◦, the fillout factor (𝑓) equals 0.0961, and the temperature ratio (𝑇2∕𝑇1) is 0.9740. Although not statistically …

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Finding High Mass X-Ray Binaries In Ngc 3109, Caeden Miller, John (Jay) Gallagher Iii

Macalester Journal of Physics and Astronomy

High Mass X-Ray Binary systems can be difficult to find in the Milky Way due to high metallicity contributing to mass loss due to stellar wind, so we turn our attention to the galaxy NGC 3109 in order to find these systems. Using archival data from the Hubble Space Telescope using the Wide Field Camera 3, we do photometry in both the F475W and F814W filters for the two fields of view that cover the galaxy. We then plot these magnitudes on a color-magnitude diagram and use isochrones of 5 and 10 million years to gather minimum mass estimates of …

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Electro-Optic Detection Of Plasma Generated Thz Pulses, Rohan Lichtenberg, James Heyman

Macalester Journal of Physics and Astronomy

We implement a technique of generating ultrafast THz-pulses for use in a time-resolved THz-spectroscopy system. We focus light emitted by an amplified Ti:Sapphire Laser in order to ionize a small filament of air, causing the formation of plasma. When laser pulses cross the plasma the Kerr effect produces measurable, ultrafast THz pulses. More specifically, we characterized pulse length and spectral bandwidth of the generated THz-pulses by examining the response by different electro-optical crystals of different thicknesses. This THz spectroscopy system is currently being used to measure the mobilities of photoelectrons in Methylammonium Lead Iodide perovskite materials, which are potential substitutes …

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Making And Breaking Chaos: Analog Computer Implementation Of The Lorenz Model, Reed Lefevre, James Doyle

Macalester Journal of Physics and Astronomy

Hybrid analogue-digital computers have been shown to have certain advantages over traditional digital computers when solving nonlinear partial differential equations. Motivated by this fact, we implement the Lorenz equations on an analogue electronic computer and vary the parameters to analyze the bifurcations. With the working circuit, we compared experimental results to various digital simulations to assess the effectiveness of our circuit. We find clear qualitative agreement between the physical circuit and digital simulations; however, we observe a noticeable quantitative difference in behavior. The circuit depicts a picturesque Lorenz Butterfly plot and bifurcates into fixed points and chaos; however, these bifurcations …

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Non-Destructive Compositional Analysis Of Lead Halide Perovskite Films Using Thz Spectroscopy And A Three-Oscillator Dielectric Model, Isaac J.C Kisker

Macalester Journal of Physics and Astronomy

Terahertz (THz) Spectroscopy offers a novel approach to probing low-energy phonon excitation in complex crystalline materials like methylammonium lead iodide (MAPI) perovskite films. In this research, we use time-resolved Terahertz Spectroscopy in tandem with a three-oscillator model to non-destructively ascertain the relative volumetric composition of MAPI and residual lead iodide (PbI₂) in spin-coated films. The dielectric function is modeled as a product over longitudinal and transverse optical phonon modes. This model is then fitted to the measured THz spectra, allowing us to extract the contributions from both MAPI and PbI₂.

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Monitoring The Degradation Of Methylammonium Lead Iodide Perovskite Thin Films By Uv Exposure, Addison Dau, Ethan Dale, James Heyman

Macalester Journal of Physics and Astronomy

This project involved lead-halide perovskite thin films, a promising novel solar cell material. The goal was to monitor the composition of the samples during degradation from blue light exposure using vibrational spectroscopy. IR and THz spectroscopy measured the composition of the samples in-situ between periods of blue light exposure, probing the N-H and Pb-I vibrational modes. Plotting MA and MAPI concentrations versus blue light exposure showed that the MA and MAPI concentrations initially decreased in a gradual linear fashion until a threshold photon flux where both vibrational absorption bands simultaneously collapsed. This suggests that there is a discontinuous change in …

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Electropolymerization Of Nile Blue And Toluidine Blue Dyes For Hydrogen Evolution Reaction Electrocatalysts, Camellia N. Schwartzman

Macalester Journal of Physics and Astronomy

This work investigated electropolymerized (EPD) organic conductive polymers poly-Nile Blue (PNB) and poly-Toluidine Blue (PTB) on fluorine-doped tin oxide (FTO) glass substrates as electrocatalysts for the hydrogen evolution reaction (HER). We investigated the effect of changing the heteroatoms in the pi-conjugated structure of poly-Neutral Red (PNR). UV-vis spectroscopy was used to estimate film thickness. Catalytic activity was quantified by Tafel slope and formal redox potential. PNB and PTB exhibited low current densities and small standard rate constants. Although neither showed highly active catalysts for HER, future directions should continue to pursue structures similar to PNR for HER electrocatalysts.

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Examining Mulit-Wavelength Variability And Magnetic Interactions In The Polar St Lmi, Cain Rinkoski

Macalester Journal of Physics and Astronomy

Cataclysmic variable (CV) stars are interacting binary systems that exhibit exotic, multi-wavelength behavior driven by mass transfer from a donor star onto a white dwarf. As rich laboratories for accretion physics, binary dynamics, and the origins of Type Ia supernovae, CVs have been well studied in the X-ray, ultraviolet, optical, and infrared—but remain comparatively underexplored in the radio regime. This paper presents simultaneous, time-resolved optical and radio observations of the magnetic CV ST LMi, aimed at constraining its emission mechanisms and orbital modulation.
The optical light curves display brightness variations of approximately 1.31 ± 0.02 magnitudes on a period of …

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A Thermal Control System For The Atlas Hgtd Module Construction Process, Keelin B. Murphy

Macalester Journal of Physics and Astronomy

In the aim of simplifying the production process of 2000 HGTD (High Granularity Timing Detector) modules at IJClab for the high luminosity phase of the ATLAS experiment at the CERN Large Hadron Collider, I designed, coded, and constructed an automatic temperature control system for module assembly and testing. To this end, I examined the module’s thermal response to changes in air temperature using a climate chamber and to various currents fed through a Peltier device situated under the module. I adapted the Peltier setup into a fully independent control system driven by an Arduino microcontroller running a PID feedback loop.

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Pancho And The Bandits From Arizona, Daniel W. Jacobs

Night Flight: Online Literary Journal

When a crew of bandits cannot seem to steal money without being held up by the local sheriff, they decide it is time for something new. Traveling even more west than Arizona they find themselves in San Francisco, a city with endless possibilities. The bandits become successful in the new city and word travels throughout the west and eventually the sheriff who was always one step ahead of the bandits, but could never finish the job, heard about the bandits success in San Francisco.

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