The USA/USM/SELU research mini-conference is a (very) regional one-day meeting, featuring research presentations in the physical and mathematical sciences from students and faculty from universities in the Gulf Coast area. A principal goal of this conference is to involve undergraduate students in research and provide an opportunity for them to present their work. There is no conference fee, and a free lunch will be provided to all participants.
We encourage interested faculty and students, including those who may not want to present, to attend and learn more about research going on in our Gulf area. For more information, please contact one of the local organizers:
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Koray Akozbek and W. Tyler McCleery
(University of South Alabama)
(15min) Spatial and temporal dependence of nutrient delivery in Arabidopsis
Abstract.
Modern agriculture cannot keep up with the quickly growing global population. One innovative farming solution involves hydroponics, which reduces the land area and water volume required for crops. We aim to enhance the benefits of hydroponics by controlling nutrient delivery for optimal growth. Using the plant, Arabidopsis, we test the hypothesis that root branching does not directly correlate to higher nutrient concentration. To study the spatial and temporal dependence of nutrient delivery on root growth, we designed a controllable single channel hydroponic device. After the root has grown for a period of seven days, the roots can be imaged to see how many lateral roots have formed. We show preliminary biophysical calculations and experimental set-up to test growth dependency.
- Ryan Ankersen and John Jennings (Springhill College)
(15min) Measuring Partisan Bias in State Redistricting
Abstract.
Our research looks at measuring partisan bias in the US House of Representatives district maps, and how it relates to redistricting states. Our research aims to quantify biases in these maps, commonly referred to as partisan gerrymandering. The inspiration of our project originates from a measure of wealth inequality created by Italian statistician Corrado Gini called the Gini index. Our project takes this concept and applies it to the relationship between voting for a particular party, and that party's success in clenching state districts for the House of Representatives. This method provides a metric for measuring vote to seat inequities within states given specific district maps. These seat-vote curves can be used to look at how these inequities change over time.
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Kent Clark
(University of South Alabama)
(30min) Double Stars: Measure and Publish
Abstract.
Double stars are simply two stars appearing close together in the sky. Binary stars are two stars that appear close together and are gravitationally bound to each other. Binary stars are important to astronomy as they are the only way to directly measure stellar masses, which is an important parameter in understanding stellar evolution. So, continually measuring the relative positions of binary and double stars is necessary to astronomy. It is a task that has been largely taken up by amateur astronomers and can be done by undergraduate students. These measurements can then be published in different venues and are archived by the United States Naval Observatory in the Washington Double Star Catalog.
I will describe the process of measuring double stars. I will also discuss the Journal of Double Star Observations, which is one way for those measurements to be disseminated. Finally, I will briefly describe the Washington Double Star Catalog.
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Sam Formichella
(University of South Alabama)
(15min) Gaussian binomial coefficients with negative arguments
Abstract.
We discuss an extension to the usual combinatorial interpretation of the binomial coefficients. That is, the binomial coefficient (n,k) gives the number of k-element subsets of a set with n elements, where n,k are nonnegative integers. Of course, if k is greater than n, then the binomial coefficient is zero, since there cannot be, say, a 5-element subset of a set with 3 elements. We are concerned with studying binomial coefficients and Gaussian binomial coefficients over all of the integers. Loeb [92] provides an interpretation of a set with a negative number of elements as well as what it means for a subset to have a negative or positive number of elements via a partial order. To this effect, one can establish what the binomial coefficients mean, and what the Gaussian binomial coefficients mean in terms of their weighted-sum interpretation.
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Romulus Godang
(University of South Alabama)
(15min) Recent Results with Partial Reconstruction of anti-B0 Mesons at BABAR
Abstract.
We present a precision measurement of the exclusive branching fraction of anti-B0 mesons decay to D*+ lepton anti-neutrino, where lepton is either electron or muon. The anti-B0 mesons are partially reconstructed where the D*+ mesons are detected only through the soft pion daughters of the decay D*+ to D0 pi+. The data sample was collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B-Factory at the SLAC National Accelerator Laboratory.
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Emily Grinstead
(University of South Alabama)
(30min) Multiple Log-Concavity of Finite Sequences
Abstract.
In this talk, we discuss the notion of log-concavity and multiple log-concavity of sequences. We provide an introduction to log-concavity and give several examples of log-concave sequences, including the binomial coefficients, the Stirling numbers, and numerous other combinatorial examples. Also, we explore examples in graph theory, specifically the coefficients of the chromatic polynomial and the h-vector of matroids. We catalog several properties of log-concavity, including unimodality, preservation of the ordinary and binomial convolution, and products of polynomials whose coefficients have this property of log-concavity. We discuss r-factor log-concavity. Specifically, we examine a result from Craven-Csordas and McNamara-Sagan, which shows that a sequence is infinitely log-concave if it is r-factor log-concave with \( r \ge (\sqrt{3 + 5})/2 \approx 2.618 \). Furthermore, we argue that this lower bound is indeed optimal, contrary to a result published by Raza and Ali, who claim that the lower bound can be improved to \( 1+\sqrt{2} \approx 2.414 \). We discuss C-finite sequences of second order, providing a complete classification of when such sequences are log-concave.
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Taylor Hay
(Southeastern Louisiana University)
(15min) Electric Permittivity of Free Space
Abstract.
The goal of our experiment is to measure the value of electric permittivity of free space using a parallel plate capacitor. The parallel plate capacitor is placed in an LRC Series Circuit with a known inductance and the resonance frequency was measured to calculate capacitance. The capacitor was then shorted so that the internal capacitance of the circuit could be measured. By taking the total calculated capacitance and subtracting away the reciprocal of the internal capacitance, the capacitance of the parallel plate capacitor was determined. Knowing the measured values of the parallel plate capacitor allowed us to calculate epsilon. Using this approach we were able to experimentally measure epsilon in free space within 16% error.
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Noah Whittington, Noah Palframan, Salomon Itza and Troy Henderson
(University of Mobile)
(30min) Touchdown: landing probes on space objects
Abstract.
Almost 50 years ago, humankind took a giant leap when the first human set foot on a space object other than Earth: The Moon. Nowadays, space agencies around the world are landing probes on other space objects, with the hope of one-day landing humans, too. We will discuss the introductory physics, kinematic and dynamic equations, involved in space travel; in particular, we will analyze factors that influence landing on an arbitrary space object. These equations and concepts will help determine a general safe landing speed for the space craft. Our presentation will provide a backbone of knowledge in space travel and could be expanded further with more advanced methods in physics and mathematics. We will also be providing information on future interstellar travels made by space administrations around the globe.
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Karen Kohl
(University of Southern Mississippi Gulf Coast)
(30min) Some extensions to the method of brackets
Abstract.
The method of brackets is an experimental method for symbolic evaluation of definite integrals, including many involving special functions. This talk will introduce the method and will present more recent extensions that allow for solutions of a larger class of definite integration problems.
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Cody Martin
(University of South Alabama)
(15min) π-Base: A Database of Topological Spaces
Abstract.
TBA
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Conor McGibboney
(Southeastern Louisiana University)
(15min) Deformation Dynamics in Solids
Abstract.
In conventional fracture mechanics analysis begins with a crack-tip already introduced in the model or specimen. In strength of materials, stress strain curves are designed mostly from empirical methods. Neither approach predicts where and when a fracture will occur in a solid, until a crack appears. However, Deformation Field Theory provides a mathematical framework, based on physics, to make such predictions. In this research we used Deformation Field Theory to model various loading rates in a specimen to predict the location fractures will occur. Modeling deformation, as a wave propagating through a material, allows us to study stress concentration in a material sample experiencing a uni-axial tensile load applied to one end. Since Deformation Field Theory has the same mathematical form as Maxwell's Theory, we can use electrodynamics to investigate dynamics of deformation in solids. We propose that the phenomena of arc discharge, as interpreted through the limits of Maxwell?s Equations, is analogous to fracture as described in Deformation Field Theory. When charge is locally concentrated, conductivity is increased at that point, thus arc discharge occurs. In this context conductivity is a degree of energy dissipation. In our model, when stress is locally concentrated in the specimen, the region will become less elastic, more energy dissipative. As long as the stress concentrated point is still moving, the fracture will not occur. When the stress concentrated point stops moving, fracture occurs. The final fracture will begin to occur when the deformation wave becomes stationary. Empirically we know that pulling a material fast will cause a material to reach its max yield point, we also know that pulling a material slowly can cause a material to maintain the yield at this low yield point. We observed what is known empirically that if one pulls faster on a material the yield stress goes up, conversely if one pulls slower on a material the yield stress goes down. Using our model, we can demonstrate these concepts, already known in a phenomenological sense, without using empirical data acquired from stress strain analysis. Thus, we are able to predict where fractures will occur in modeled material samples.
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Errieol Milliner
(University of South Alabama)
(15min) Magnetic Monopole Clustering Algorithm
Abstract.
The existence of the magnetic monopole has eluded physicists for centuries. The search for this particle is important because it would help explain why charge is quantized. As part of the international NOvA Collaboration, we use data from NOvA's high energy particle detector located in Ash River, MN to search for such monopoles. This detector is the first massive detector (14,000 tons) of its kind to be so close to the surface of the earth making it an ideal monopole detector. The first stage of the monopole search algorithm is to remove obvious non-monopole particles (e.g. cosmic-ray muons) from the data, this stage is known as clustering. In this poster, I will present a detailed study of the various elements that make up the initial clustering algorithm.
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Josh Robbins
(University of South Alabama)
(15min) History of the Neutrino
Abstract.
The first theoretical proposition of the neutrino was given by Wolfgang Pauli in 1930, who claimed there was an apparent loss of energy and momentum while observing radioactive beta decay. Therefore, Pauli believed energy was being released into an unknown particle. This discovery by Pauli is the beginning of the neutrino, and the history of the study of this fundamental particle will be discussed. This history includes the first observation of a neutrino by studying particles located near a nuclear power plant, the challenge of the solar neutrino problem, leading to the realization that neutrinos may oscillate between different flavors, the first hypotheses and observations of all neutrino flavor types, and current studies that wish to learn more about the fundamental particle and its behavior.
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Samantha Taylor
(Southeastern Louisiana University)
(15min) Residual Stress Analysis on Welds Through Numerical Analysis and Experiments
Abstract.
Our final goal is to develop a method that evaluates weld induced residual stresses non-destructively. We made analysis in this study by using previously calculated strain data with Finite Element Models (FEM). We computed the associated stress considering the lowest non-linear term in the elastic-matrix elements. Our calculation allows us to evaluate the residual stress with the linear, non-linear, and total terms. The resultant total residual stress shows qualitative agreement with our previous experimental data; based on optical interferometry and X-ray diffractometry. The residual stress with the non-linear term only taken into account, indicates 1-10% change in the acoustic velocity near the weld (as to compared to non-welded or nominal values). This shows semi-quantitative agreement with our previous experimental data using acoustical elastic velocity. After experimental test were performed on the two specimens, Aluminum Alloy and Low Carbon Steel, we were able to quantitatively explain the results through mechanical and thermal analysis. The mechanical factors can alter the physical shape of the steel through machining and rolling. The thermal factors are induced by in our case welding. Through COMSOLs FEM strain models and MATLABs scripts we were able to estimate the residual stress considering the third-order elastic constants. When compared, the computed residual stresses overall are showing a reasonable pattern. This residual stress is shown near the welded area due to the thermal and mechanical impacts the material experienced. As we compared the results we did notice some parts showed values of higher residual stress, this is under investigation. The effect of third order component shows reasonable agreement with our experiments.
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Bin Wang
(University of South Alabama)
(15min) Fitting Finite Normal Mixture Models to NGS-Seq microRNA
Abstract.
Gene expressions profiled using next generation sequencing techniques are highly discretized and have a lot of zeros. This poses difficulties to modeling the NGS gene expression data. Based on a two-component measurement error model, we propose to model the NGS gene expression data using finite mixture models and fit the distributions using an EM-algorithm via data binning. Two different permutation tests are developed to detect the differentially expressed genes. The applications of the proposed methods will be illustrated through a real TCGA breast cancer dataset.
