Digital Commons Network^™

Geological Structure And Possible Mineralized Zones In Ikungi – Manyoni Area, Tanzania: Delineated From High-Resolution Aeromagnetic Data, Raymond K. Pius, Michael M. Msabi

Tanzania Journal of Science

Understanding geological structures is important in mineral exploration. Delineating subsurface geological structures, structural intersections, and complexities of potential geological settings for the formation of hydrothermal mineral deposits, such as gold requires using magnetic data, particularly, high-resolution aeromagnetic data. To define possible targets for mineral exploration, this study used linear detection and the Centre for Exploration Targeting (CET) techniques on high-resolution aeromagnetic data for structural delineation and interpretation. The study's conclusions indicate that the majority of geological features, such as faults, shears, fault intersections, and fracture systems, trend NE-SW, N-S, and occasionally NW-SE. These structures create potentially large areas that have …

Influence Of Stacking Order On The Structural And Optical Properties Of Cu2znsns4 Absorber Layer Prepared From Dc-Sputtered Oxygenated Precursors, January S Gwaydi, Hezekiah B Sawa, Egidius R Rwenyagila, Nathanael R Komba, Talam E Kibona, Nuru R Mlyuka, Margaret E Samiji, Lwitiko P Mwakyusa

Tanzania Journal of Science

Several studies have attempted to overcome the sudden volume expansion of the precursor during sulfurization by the use of oxygen-containing precursors when growing the CZTS absorber. This work demonstrates the influence of precursor stacking orders on the properties of the CZTS thin film absorber layer from DC-sputtered oxygenated precursors for solar cell applications. CZTS absorber layers were prepared from three types of DC-sputtered stacks, namely, Zn-O/Sn/Cu, Sn/Zn-O/Cu, and Sn/Cu/Zn-O. The precursors were sequentially deposited on a soda lime glass (SLG) using DC-magnetron sputtering and annealed in a sulfur and nitrogen ambient. X-ray diffractometry (XRD) and Raman spectroscopy analyses reveal the …

Classification Of Topological Defects In Cosmological Models, Abigail Swanson

Departmental Honors & Graduate Capstone Projects

In nature, symmetries play an extremely significant role. Understanding the symmetries of a system can tell us important information and help us make predictions. However, these symmetries can break and form a new type of symmetry in the system. Most notably, this occurs when the system goes through a phase transition. Sometimes, a symmetry can break and produce a tear, known as a topological defect, in the system. These defects cannot be removed through a continuous transformation and can have major consequences on the system as a whole. It is helpful to know what type of defect is produced when …

Empirical Models Of The Hβ Broad Emission Line Gas Density Field, Lizvette Villafaña, Tommaso Treu, Lourenzo Colleyn, Brendon J. Brewer, Aaron J. Barth, Matthew A. Malkan, Vivian U, Vardha N. Bennert

Physics

We present the second iteration of the caramel-gas code, an empirical model of the broad-line region (BLR) gas density field. Building on the initial development and testing of caramel-gas, we expand the meaning of the model parameter α, which initially represented only the power-law index of the dependency of emissivity on radial distance. In this work, we test a more generalized radial power-law index, α, that also includes a description of the effective emitting size(s) of the BLR structure as a function of radial distance. We select a sample of 10 active galactic nuclei (AGN) from three different …

Surface Treatments' Effects On The Capacitor's Dielectric Performance Under Electro-Thermal Stresses, Haider. M. Umran, Feipeng Wang

Karbala International Journal of Modern Science

Biaxial-oriented polypropylene (BOPP) films are characterized by unfavorable aging behavior because of their poor susceptibility to high temperatures, humidity, and high electric fields. This makes them unqualified to withstand harsh operating conditions, such as in capacitor applications. This study investigates the impact of annealing BOPP samples at 100 °C for five hours after fluorination at different times (15, 30, and 60 minutes) on their electrical and mechanical performance under electro-thermal stresses. Scanning electron microscope (SEM) images confirm that there is an increase in surface roughness and the formation of a dense layer of fluorine-containing groups monotonically with fluorination time. So, …

Simulating Ice Particle Properties Under Varying Electric Fields, Joseph Cooney

Physics Capstone Projects

In this study, the interactions between atmospheric water molecules and an electrically charged dust particle were simulated in python to determine the role of electric charge and electric fields in atmospheric ice formation. Multiple levels of electric charge were tested, corresponding to different strengths of atmospheric electric fields. The TIP4P-2005 model for water was used to simulate these molecules under the influence of a central electric potential to represent the charged dust particle. These included a control group with no electric field (0 C), a group under a fair-weather strength of electric field (1.6*10-14 C), a foul-weather electric field (1.6*10-12 …

Piezochromic Behavior Of 2,4,6-Triphenylpyrylium Tetrachloroferrate, Princess Canasa, David King, Petrika Cifligu, Adrian F. Lua Sanchez, Si L. Chen, Haesook Han, Trimaan Malik, Brant Billinghurst, Jianbao Zhao, Changyong Park, George R. Rossman, Michael Pravica, Pradip K. Bhowmik, Egor Evlyukhin

Chemistry and Biochemistry Faculty Research

In advanced photonics, there is a growing interest in piezochromic luminescent materials that exhibit multicolor switching, driven by their potential applications in optical recording, memory, and sensors. Here, the piezochromic behavior of 2,4,6-triphenylpyrylium tetrachloroferrate (Py-FeCl₄) under high pressures from 0 to 9 GPa is reported. The observed multicolor changing properties of Py-FeCl₄ (yellow–orange–red–maroon–black) are found to be fully reversible upon decompression to ambient conditions. The mechanism of Py-FeCl₄ piezochromism is investigated via Raman, infrared, and UV–vis spectroscopy combined with powder X-ray Diffraction. The absence of structural phase transitions as well as the abrupt shifts of bandgap …

Measuring Soot In A Novel Configuration For Diffusion Flames Fueled By Ethylene Doped With Iso-Dodecane, Christian Bjork

Honors Scholar Theses

Sustainable Aviation Fuels (SAFs) are seen as the path forward for decarbonizing hard-to-electrify sectors. Using SAFs over traditional fossil fuels abates carbon dioxide emissions but still may present soot emission problems. A milestone in the abatement of soot would be understating its formation mechanisms.

This study aims to quantify soot products resulting from an ethylene flame doped with iso-dodecane, a surrogate SAF component. The burner selected for the investigation is the novel Planar Mixing Layer Flame (PMLF) which allows the tracking of soot formation with the height above the burner (HAB) in a stable diffusion flame. A baseline ethylene-fueled flame …

Thermal Performance Investigation Of Thermoelectric Cooling System With Various Hot-Side Cooling Methods, Bowo Y. Prasetyo, Parisya P. Rosulindo, Fujen Wang

Makara Journal of Technology

Thermoelectric devices have been widely used in various applications, including cooling and power generation. The potential application of thermoelectric cooling systems has been studied. However, these systems still face challenges in achieving optimal performance compared with other cooling systems. Several factors, including the hot-side cooling method, influence the performance of thermoelectric systems. This study aimed to investigate the effects of different hot-side cooling methods on the thermoelectric performance and thermal behavior of thermoelectric cooling systems. The testing methods involved the combination of the thermoelectric module with five hot-side heat exchangers, including a square heatsink, a round heatsink, a two-pipe heat …

Mapping Star Formation Histories In Nearby Galaxies To Source Lyman Continuum Photon Escape, Katie Kudla '24

Engineering & Physics Student Scholarship

Katie Kudla ’24, Physics major
Faculty Mentor: Dr. Joseph Ribaudo, Engineering and Physics

The Heavy Metal Survey: Star Formation Constraints And Dynamical Masses Of 21 Massive Quiescent Galaxies At Z = 1.3-2.3, Mariska Kriek, Aliza G. Beverage, Sedona H. Price, Katherine A. Suess, Guillermo Barro, Rachel S. Bezanson, Charlie Conroy, Sam E. Cutler, Marijn Franx, Jamie Lin, Brian Lorenz, Yilun Ma, Ivelina G. Momcheva, Lamiya A. Mowla, Imad Pasha, Pieter Van Dokkum, Katherine E. Whitaker

Pacific Faculty Work

In this paper, we present the Heavy Metal Survey, which obtained ultradeep medium-resolution spectra of 21 massive quiescent galaxies at 1.3 < z < 2.3 with Keck/LRIS and MOSFIRE. With integration times of up to 16 hr per band per galaxy, we observe numerous Balmer and metal absorption lines in atmospheric windows. We successfully derive spectroscopic redshifts for all 21 galaxies, and for 19 we also measure stellar velocity dispersions (σ v ), ages, and elemental abundances, as detailed in an accompanying paper. Except for one emission-line active galactic nucleus, all galaxies are confirmed as quiescent through their faint or absent Hα emission and evolved stellar spectra. For most galaxies exhibiting faint Hα, elevated [N ii]/Hα suggests a non-star-forming origin. We calculate dynamical masses (M dyn) by combining σ v with structural parameters obtained from the Hubble Space Telescope COSMOS(-DASH) survey and compare them with stellar masses (M *) derived using spectrophotometric modeling, considering various assumptions. For a fixed initial mass function (IMF), we observe a strong correlation between M dyn/M * and σ v . This correlation may suggest that a varying IMF, with high-σ v galaxies being more bottom heavy, was already in place at z ∼ 2. When implementing the σ v -dependent IMF found in the cores of nearby early-type galaxies and correcting for biases in our stellar mass and size measurements, we find a low scatter in M dyn/M * of 0.14 dex. However, these assumptions result in unphysical stellar masses, which exceed the dynamical masses by 34%. This tension suggests that distant quiescent galaxies do not simply grow inside-out into today’s massive early-type galaxies and the evolution is more complicated.

Towards A Practical Method For Monitoring Kinetic Processes In Polymers With Low-Frequency Raman Spectroscopy, Robert Vito Chimenti

Theses and Dissertations

Unlike liquids and crystalline solids, glassy materials exist in a constant state of structural nonequilibrium. Therefore, a comprehensive understanding of material kinetics is critical for understanding the structure-property-processing relationships of polymeric materials. Amorphous materials universally display low-frequency Raman features related to the phonon density of states resulting in a broad disorder band for Raman shifts below 100 cm-1, which is related to the conformational entropy and the modulus. This disorder band is dominated by the Boson peak, a feature due to phonon scattering because of disorder and can be related to the transverse sound velocity of the material, and a …

Gate-Controlled Supercurrent Effect In Dry-Etched Dayem Bridges Of Non-Centrosymmetric Niobium Rhenium, Jennifer Koch, Carla Cirillo, Sebastiano Battisti, Leon Ruf, Zahra Makhdoumi Kakhaki, Alessandro Paghi, Armen Gulian, Serafim Teknowijoyo, Giorgio De Simoni, Francesco Giazotto, Carmine Attanasio, Elke Scheer, Angelo Di Bernardo

Mathematics, Physics, and Computer Science Faculty Articles and Research

The application of a gate voltage to control the superconducting current flowing through a nanoscale superconducting constriction, named as gate-controlled supercurrent (GCS), has raised great interest for fundamental and technological reasons. To gain a deeper understanding of this effect and develop superconducting technologies based on it, the material and physical parameters crucial for the GCS effect must be identified. Top-down fabrication protocols should also be optimized to increase device scalability, although studies suggest that top-down fabricated devices are more resilient to show a GCS. Here, we investigate gated superconducting nanobridges made with a top-down fabrication process from thin films of …

Demonstration Of High-Impedance Superconducting Nbre Dayem Bridges, S. Battisti, J. Koch, A. Paghi, L. Ruf, Armen Gulian, Serafim Teknowijoyo, C. Cirillo, Z. Makhdoumi Kakhaki, C. Attanasio, E. Scheer, A. Di Bernardo, G. De Simoni, F. Giazotto

Mathematics, Physics, and Computer Science Faculty Articles and Research

Here, we demonstrate superconducting Dayem-bridge weak-links made of different stoichiometric compositions of NbRe. Our devices possess a relatively high critical temperature, normal-state resistance, and kinetic inductance. In particular, the high kinetic inductance makes this material a good alternative to more conventional niobium-based superconductors (e.g., NbN or NbTiN) for the realization of superinductors and high-quality factor resonators, whereas the high normal-state resistance yields a large output voltage in superconducting switches and logic elements realized upon this compound. Moreover, out-of-plane critical magnetic fields exceeding 2 T ensure that possible applications requiring high magnetic fields can also be envisaged. Altogether, these features make …

Deep Selenium Donors In Zngep2 Crystals: An Electron Paramagnetic Resonance Study Of A Nonlinear Optical Material, Timothy D. Gustafson, Larry E. Halliburton, Nancy C. Giles, Peter G. Schunemann, Kevin T. Zawilski, J. Jesenovec, Kent L. Averett, Jonathan E. Slagle [*]

Faculty Publications

Zinc germanium diphosphide (ZnGeP₂) is a ternary semiconductor best known for its nonlinear optical properties. A primary application is optical parametric oscillators operating in the mid-infrared region. Controlled donor doping provides a method to minimize the acceptor-related absorption bands that limit the output power of these devices. In the present study, a ZnGeP₂ crystal is doped with selenium during growth. Selenium substitutes for phosphorus and serves as a deep donor. Significant concentrations of native defects (zinc vacancies, germanium-on-zinc antisites, and phosphorous vacancies) are also present in the crystal. Electron paramagnetic resonance (EPR) is used to establish the …

A Jwst Survey Of The Supernova Remnant Cassiopeia A, Dan Milisavljevic, Tea Temim, Ilse De Looze, Danielle Dickinson, J. Martin Laming, Robert Fesen, John C. Raymond, Richard G. Arendt, Jacco Vink, Bettina Posselt, George G. Pavlov, Ori D. Fox, Ethan Pinarski, Bhagya Subrayan, Judy Schmidt, William P. Blair, Armin Rest, Daniel Patnaude, Bon Chul Koo, Jeonghee Rho, Salvatore Orlando, Hans Thomas Janka, Moira Andrews, Michael J. Barlow, Adam Burrows, Roger Chevalier, Geoffrey Clayton, Claes Fransson, Christopher Fryer, Haley L. Gomez, Florian Kirchschlager

Michigan Tech Publications

We present initial results from a James Webb Space Telescope (JWST) survey of the youngest Galactic core-collapse supernova remnant, Cassiopeia A (Cas A), made up of NIRCam and MIRI imaging mosaics that map emission from the main shell, interior, and surrounding circumstellar/interstellar material (CSM/ISM). We also present four exploratory positions of MIRI Medium Resolution Spectrograph integral field unit spectroscopy that sample ejecta, CSM, and associated dust from representative shocked and unshocked regions. Surprising discoveries include (1) a weblike network of unshocked ejecta filaments resolved to ∼0.01 pc scales exhibiting an overall morphology consistent with turbulent mixing of cool, low-entropy matter …

Implementation Of Python Based High Voltage Tests For Gem Detectors, John Paul Hernandez

Aerospace, Physics, and Space Science Student Publications

The Compact Muon Solenoid, CMS, and other detectors at LHC are in the process of being upgraded for the HL-LHC (High-Luminosity Large Hadron Collider) which will produce more than 5 times the particle interactions than of the current LHC. One upgrade to CMS is the introduction of new GEM detectors (Gaseous Electron Multiplier), GE2/1 and ME0 shown at right are new detectors to CMS and therefore must be tested thoroughly prior to being installed.

Novel Technique Using Cherenkov Radiation For Nuclear Terrorism Prevention, Matthew Mark Romano

Aerospace, Physics, and Space Science Student Publications

I present a novel approach for detecting rogue nuclear material at country borders, addressing the current lack of reliable and economical mechanisms for this purpose. My proposed methodology utilizes Cherenkov radiation emitted by cosmic muons to reconstruct the particle's trajectory using a single detector. By analyzing the eccentricity of the projected ellipse formed when the Cherenkov cone intersects the detector plane, one can determine the angle a muon makes with the detector. This innovative technique effectively doubles the efficiency of the detection system by halving the number of required detectors while simultaneously increasing the resolution of the measurements taken.

Synthesis And Characterization Of Hexagonal Boron Nitride Nanosheets, Josiah J. Deonarine

Honors Theses

Certain defects within the hexagonal boron nitride (hBN) lattice are a promising source of quantum mechanical states for quantum computing. It is difficult to produce layers of hBN that are thin enough for these quantum states to be studied. We investigate ultrasonic liquid exfoliation and hydrothermal synthesis as methods of synthesizing hBN nanosheets. Samples were analyzed through light scattering spectroscopy and atomic force microscopy. Our results show that liquid exfoliation can produce hBN nanosheets that range in between 0.35nm - 20nm in thickness. We also show hydrothermal synthesis reactions, between boric acid and nitrogen sources, that can produce hBN nanosheets.

Plasma Diagnostics For Anode Cathode Plasmas And High Energy Density Physics On A Linear Transformer Driver, Robert Beattie-Rossberg

Electrical and Computer Engineering ETDs

A twelve-brick air insulated linear transformer driver (LTD) was characterized by charging to voltages ranging from 30 to 70 kV and delivering energy to two separate resistive loads. Various plasma diagnostics were built and fielded with an emphasis on the design, implementation and analysis of a Mach Zehnder interferometer, a moiré deflectometer and a spectroscopy system providing information on the temporal evolution of plasma electron density and atomic composition. Rogowski coils, XRD radiation detectors, framing camera images and time integrated DSLR images are used to further understand load conditions where current data, x ray radiation data, velocity data and instability …

Adapt Laser Shaping, Quinlin Reynolds

ATU Scholars Symposium

Investigation into producing a machine learning algorithm that allows a He-Ne laser to classify whether a produced beam shape is uniformly gaussian or not, in order to adaptively move the laser to consistently target the encoded interference pattern area. This will then result in continuous uniform beam shapes of the desired output.

Uncharted: Measuring Beyond The Inner Galaxy, Carly J. Fitzgerald, Sammy Schneider, Landyn Schroeder

Research & Creative Achievement Day

My goal in conducting my research was to measure the speed of matter in the Milky Way galaxy using CHART -- the Completely Hackable Amateur Radio Telescope is an inexpensive, constructable telescope used to detect radio frequency waves in the galaxy. Using these waves and the doppler shift equation, I was able to measure the velocity of hydrogen gas in the inner galaxy. In doing this successfully, I was able to graph the relationship between the velocity and radius which is the rotational curve of the inner galaxy. I then collected and used additional data to calculate the rotational curve …

Anomalies Within Winona Campus On Protected Wavelengths, Landyn L. Schroeder, Carly Fitzgerald, Sammy Schneider

Research & Creative Achievement Day

The present study is being conducted with the intention of identifying where, why, and what is transmitting a radio signal of 1419 MHz. This anomaly is intriguing because 1400-1427 MHz waves are protected. Because this is a protected wave, it was interesting that it was being transmitted on Winona State Campus which is where the team began research. To gain information, the research team cast the horn to the sky at an elevation of 37 degrees and in the directions of 344 , 213, 143, and 60 degrees bearing, respectively. Now that this baseline information has been collected, the team …

Exact Treatment Of Weak Dark Matter-Baryon Scattering For Linear-Cosmology Observables, Y. Ali-Haïmoud, S. S. Gandhi, Tristan L. Smith

Physics & Astronomy Faculty Works

Elastic scattering of dark matter (DM) particles with baryons induce cosmological signals that may be detectable with modern or future telescopes. For DM-baryon scattering cross sections scaling with negative powers of relative velocity, 𝜎_𝜒⁢𝑏⁡(𝑣) ∝𝑣⁻²,𝑣⁻⁴, such interactions introduce a momentum-exchange rate that is nonlinear in DM-baryon bulk relative velocities, thus not amenable for inclusion as-is into standard linear cosmological Boltzmann codes. Linear Ansätze have been adopted in past works, but their accuracy is unknown as they do not arise from first-principles derivations. In this work, for the first time, we construct a rigorous framework for computing linear-cosmology observables …

Radiative Cooling For Energy-Efficient Power Generation, Rickia Hanna

Celebrating Scholarship and Creativity Day (2018-)

This thesis examined radiative cooling on a small scale using a hybrid photovoltaic/radiative cooling model system, to determine its efficiency for large-scale power generation. Radiative cooling is concerned with heat transfer and this thesis’s main goal is to harness that heat energy to produce electricity. The efficiency of the system was tested using various light sources at different angles and total power output. The testing was done several times and there proved to be a proportional relationship between light intensity and current output. However, due to the performance threshold of the PTEC module, the component of the system used to …

Investigating The Magnetic Cycle Of The Planet-Hosting Star Hd189733, Mohammad Samih Husein

Thesis/ Dissertation Defenses

HD189733 is a planet-hosting star, harboring a hot Jupiter situated at approximately 8.8 stellar radii. This system is among the most studied systems for stellar magnetism, Star-Planet Interactions, and exoplanetary atmospheric studies. The large-scale magnetic field of the star exhibits variability on relatively short timescales, however, no magnetic field cycle, including polarity flips, has been observed to date. This absence of cycle detection could be due to observational gaps between observing campaigns. This thesis aims to explore the variability of the activity of HD189733 by conducting a homogeneous analysis of several publicly available datasets, obtained using several spectrographs/telescopes, spanning 18 …

A New Effective Gravitational Lensing Approach To Constrain Dark Matter, Birendra Dhanasingham

Physics & Astronomy ETDs

Galaxy-scale strong gravitational lenses offer a unique window into understanding the nature and distribution of dark matter at sub-galactic scales. Beyond the main-lens subhalos, the inclusion of line-of-sight dark matter halos has become essential in lens studies due to their substantial role in perturbing lensed images, making multi-plane lensing a crucial aspect of any lens study. We highlight that these line-of-sight halos appear extended tangentially along the lensing critical line in the effective convergence maps due to the nonlinear nature of multiplane lensing, resulting in a characteristic anisotropic signature in the deflection field. Leveraging tools from large-scale structure analyses, this …

Investigation Of Superconducting Properties In Ybco Using Proton Irradiation, Joseph Fogt, Hope Weeda, Trevor Harrison, Nolan Miles

23rd Annual A. Paul and Carol C. Schaap Celebration of Undergraduate Research and Creative Activity (2024)

We studied the effect of 600 keV proton irradiation on thin-film Cuprate superconductors. A 500 nm thick YBCO-1237 sample was subjected to a series of proton irradiations using Hope College’s particle accelerator, using a cryocooler to test the resistivity of the sample in between irradiations. We found that the superconducting critical temperature (T_C) drastically decreased from 90 K towards zero Kelvin, and the normal state resistivity increased accordingly. The rate of T_C reduction to resistivity increase will be used to discuss the fundamental property of the superconductor.

Characterization And Testing Of Sipms For A Next-Generation Neutron Detector, Bishop Carl

23rd Annual A. Paul and Carol C. Schaap Celebration of Undergraduate Research and Creative Activity (2024)

MoNA-LISA is a position-sensitive neutron detector at the Facility for Rare Isotope Beams (FRIB) used to probe neutron-unbound states through invariant-mass spectroscopy. Position resolution of the neutron detector is a key factor in invariant mass measurements. A better neutron position would significantly improve the overall reconstructed decay energy resolution and would therefore lead to a better understanding of nuclei near and beyond the dripline. The MoNA collaboration is designing a next-generation neutron detector to improve the current MoNA-LISA resolution (~5cm). The new design will replace the PMTs for SiPM arrays as readout technology. The use of SiPMs (more compact) for …

Material Characterization For Industrial Processes Of Thin Titanium Nanotube Films, Nathaniel Jobson, Jacob Walther, Justin Rink, Wil Pinkerton

23rd Annual A. Paul and Carol C. Schaap Celebration of Undergraduate Research and Creative Activity (2024)

Material characterization is an important step in the experimental processes. This step ensures that the samples' processing yields the intended results. This work outlines the process taken to analyze and characterize a set of industrial thin films. Our characterization starts with an elemental baseline from scanning electron microscopy (SEM). The composition is verified by SimNRA (Simulation Nuclear Reaction Analysis) calculations fitting Rutherford Backscattering (RBS) data collected from a silicon surface barrier (particle) detector.