Western Kentucky University
Department of Physics and Astronomy

Colloquium

WKU Physics Majors & Graduate

Department of Physics and Astronomy
Western Kentucky University

"Undergraduate Research Projects"

September 11, 2017 @ 4:00 pm in TCCW 201

Abstract

Carson King
"A Comparison of Coronal Dimming Behavior Between XRT and AIA Data"

A coronal dimming is an event that takes place in the sun’s atmosphere, in which a patch of bright plasma seemingly disappears leaving a dark spot. These events are often associated with other solar phenomena such as flares and coronal mass ejections. Over the lifetimes of the SDO/AIA and Hinode/XRT telescopes many of these dimmings have been observed, however very few have been studied using XRT data. For this project one event was selected, and the goal was to measure how the area of the dimming region behaved over time in relation to other events in the area. In doing this, a new objective method for determining a threshold between the dimming region and the surrounding area was developed which can now be used to analyze the area of almost any dimming region. After comparing the region’s behavior over multiple wavelengths, our results support the common theory that these dimmings are caused by an evacuation of plasma due to opening magnetic field lines, rather than a sudden temperature change.

Devon Loomis
"Using an Electronic Nose for Detection of Spoiled Food"

We analyzed the sensor response to o-gassing caused by the spoilage of meat using the SGX MiCS-6814. The SGX MiCS-6814 is an array of 3 independent metal oxide semiconducting sensors, each of which respond to different kinds of gases present in the air. Sensor response is determined by the change in the conductivity of the sensor after exposure to the gases that it detects. This change is caused by the replacement of the molecules of O2 with the molecules of another gas on the surface of the metal oxide. Storing the meat in a 4C refrigerator produced voltages across the sensor that showed minimal variation for the rst 10 days and then showed a definitive trend of increasing voltage response for each day thereafter. These results confirmed the ability of the sensors to produce a relationship between response and spoilage after a critical time was reached. The next step is to find a practical way of mathematically defining this relationship. For this, we hope to quantify spoilage as the number of colony forming units (cfu0s) that are present on the meat. By counting the colonies and finding the sensor response on a sample over various stages of its spoilage process, we hope to show that the electronic nose is a dependable way to determine the level of spoilage of meats and if they are t for consumption according to known biological food safety standards.

Seth Harper
"Detecting Spoiled Meat using Novel Metal Oxide Sensors"

Having the ability to tell if food is spoiled has always been a touch-and-go concept at best. The manufacturer posts a “best by” date and past that the only way to tell is by smell. So, what if it was possible to use an electronic nose to smell the meat and tell if it is spoiled or not? That is the purpose of this experiment. Using the sensor array SGX MiCS-6814, which is an array of 3 separate metal oxide sensors that detect when different gases are nearby. When a sensor is turned on the surface begins to heat up, which causes electrons to leave the surface. This causes the sensors to be highly reactive. When a gas that fits the specific type of sensor is near the surface, it will oxidize the surface of the sensor which will cause a change in resistance. This change in resistance creates the signal that is measured. The primary focus of this experiment is to take various stages of spoiled meat and record a sensor response for these stages. This response will then be compared to biological colony counts. This will provide some proof that the sensor shows that the meat is spoiled. The first task was to find a calibration curve for the sensor array. Meat was purchased on the day of slaughter and transported to the lab within 3 hours of actual slaughter time. This was done to assure the freshest possible sample. The meat was stored in a lab refrigerator at 4o C. Measurements were taken daily for the following weeks to see how the response varied as the meat became more spoiled. The first 10 days provided little results, however the response started to change after that day and followed an expected trend. This proves that the sensor response does change as expected when meat expires. The next step is to take these measurements alongside culturing bacteria.

Zachary C. Thomas
"Electron Diffraction Monitoring of Graphene Growth by Pulsed Laser Deposition"

Graphene is a 2D, hexagonal carbon lattice that exhibits excellent thermal and electrical properties which make it a viable application in material sciences, condensed matter physics, and biological and optical engineering studies. Single layer graphene is not desirable for microelectronic applications due to its zero-energy band gap. Recently more focus has been directed toward the synthesis of multi- and few-layer graphene. In this research, few-layer graphene will be deposited on a silicon substrate by pulsed laser deposition (PLD) of a carbon target in an ultra-high vacuum (UHV) chamber. Three different wavelengths of a Nd:YAG laser will be used (1064 532, and 355 nm) to determine the optimal wavelength for thin film deposition. An electronic excitation of the substrate will be used to heat the substrate between 500 – 800 C. This is a more efficient heating method than that used in chemical vapor deposition (CVD) of thin films. A Reflection High Energy Electron Diffraction technique will be utilized to better understand the mechanics of the growth process in thin films during PLD.

Benjamin Thornberry
"Investigating the Effects of a Charged Black Hole on Entangled Qubits"

We (Dr. Andrew, Dr. Steinfelds, and myself) are using Mathematica to investigate the effects of the environment near a charged black hole on entangled qubits. We are doing this by constructing a Bell state then taking the tensor product of this with a matrix representing the thermal environment around a charged (Reissner-Nordstrom) black hole, then plotting entanglement measures (such as concurrence) as functions of time and other parameters. In my talk, I will spend most of the time explaining the properties of qubits and how to construct an entangled state, and I will only briefly touch on other aspects of the project.