Digital Commons Network^™

Building Patterned Shapes In Robot Swarms With Uniform Control Signals, David Caballero, Angel A. Cantu, Timothy Gomez, Austin Luchsinger, Robert Schweller, Tim Wylie

Computer Science Faculty Publications

This paper investigates a restricted version of robot motion planning, in which particles on a board uniformly respond to global signals that cause them to move one unit distance in a particular direction. We look at the problem of assembling patterns within this model. We first derive upper and lower bounds on the worst-case number of steps needed to reconfigure a general purpose board into a target pattern. We then show that the construction of k-colored patterns of size-n requires Ω(n log k) steps in general, and Ω(n log k + √ k) steps if the constructed shape must always …

Polyhedra Circuits And Their Applications, Bin Fu, Pengfei Gu, Yuming Zhao

Computer Science Faculty Publications

To better compute the volume and count the lattice points in geometric objects, we propose polyhedral circuits. Each polyhedral circuit characterizes a geometric region in Rd . They can be applied to represent a rich class of geometric objects, which include all polyhedra and the union of a finite number of polyhedron. They can be also used to approximate a large class of d-dimensional manifolds in Rd . Barvinok [3] developed polynomial time algorithms to compute the volume of a rational polyhedron, and to count the number of lattice points in a rational polyhedron in Rd with a fixed dimensional …

Hardness Of Sparse Sets And Minimal Circuit Size Problem, Bin Fu

Computer Science Faculty Publications

We study the magnification of hardness of sparse sets in nondeterministic time complexity classes on a randomized streaming model. One of our results shows that if there exists a 2no(1) -sparse set in NDTIME(2no(1)) that does not have any randomized streaming algorithm with no(1) updating time, and no(1) space, then NEXP≠BPP , where a f(n)-sparse set is a language that has at most f(n) strings of length n. We also show that if MCSP is ZPP -hard under polynomial time truth-table reductions, then EXP≠ZPP .

Drug Delivery In Catheterized Arterial Blood Flow With Atherosclerosis, Saulo Orizaga, Daniel N. Riahi, Jose R. Soto

School of Mathematical & Statistical Sciences Faculty Publications

We study the problem of drug delivery in a catheterized artery in the presence of atherosclerosis. The problem is modeled in the context of a two-phase flow system which consists of red blood cells and blood plasma. The coupled differential equations for fluid (plasma) and particles (red cells) are solved for the relevant quantities in the reasonable limits. The drug delivery problem is modeled with a partial differential equation that is developed in terms of the drug concentration, blood plasma velocity, hematocrit value and the diffusion coefficient of the drug/fluid. A conservative-implicit finite difference scheme is develop in order to …

Development And Assessment Of An Environmental Dna (Edna) Assay For The Rio Grande Siren And Review Of Edna Metabarcoding Applications, Krista M. Ruppert

Theses and Dissertations

Environmental DNA (eDNA) assays have become a major aspect of amphibian surveys in the past decade. These methods are highly sensitive, making them well-suited for monitoring rare and cryptic species. Current efforts to study the Rio Grande Siren in south Texas have been hampered due to the cryptic nature of these aquatic salamanders. Arid conditions further add to the difficulty in studying this species, as many water bodies they inhabit are ephemeral, sometimes constraining sampling efforts to a short window after heavy rain. Additionally, sirens are known to cease activity and reside underground when ponds begin to dry or as …

Pipe Flow Of Newtonian And Non-Newtonian Fluids, Erick Sanchez

Theses and Dissertations

We consider an incompressible, viscous fluid in a cylindrical pipe. We obtain velocity profile for both Newtonian fluid and non-Newtonian fluids such as shear-thinning, shear- thickening and Bingham plastic fluids. The flow is governed by the equation of continuity (conservation of mass) and the momentum equation. After presenting the governing system in the cylindrical coordinate system and assuming that the flow is due to the pressure drop and wall shear stress, we derive the expressions for the velocity component in the axial direction for these cases. Some computational results of the velocity profiles for various cases are presented. We will …

Methods For Multi-Source Resolution In Pulsar Timing Array Based Gravitational Wave Detection, Yiqian Qian

Theses and Dissertations

With next-generation radio telescopes, namely the Five-hundred-meter Aperture Spherical Telescope(FAST) and Square Kilometer Array(SKA), scheduled to come online during this decade, hundreds of well-timed millisecond pulsars (MSPs) will be added to the Pulsar Timing Arrays (PTAs) being used currently for Gravitational Wave (GW) searches. This will greatly increase the distances to which GW sources in the very low frequency band can be detected. Among these sources will be super massive black hole binaries (SMBHBs) formed out of gigantic black holes weighing in at million to billion times the mass of our Sun. Although the large number of MSPs will improve …

Diffuse Spectra Model Of Photoluminescence In Carbon Quantum Dots, S. E. Kumekov, N. K. Saitova, Karen S. Martirosyan

Physics & Astronomy Faculty Publications

The attractive aspect of excitation related to fluorescence nature in carbon quantum dots (CQD) has guided to several assumptions correlated with clusters size distribution, shapes as well as presence of different emissive states. In this study, a dimer–excimer model of photoluminescence (PL) in CQD describing discrete multiple electronic states for the excitation-dependent emission is described. The functional dependence of the characteristic width of the diffuse spectra of PL on the size of a quantum dots are calculated. The effective width of PL spectrum can be tuned from 0.1 to 1 eV.

Adaptive Spline Fitting With Particle Swarm Optimization, Soumya Mohanty, Ethan Fahnestock

Physics & Astronomy Faculty Publications

In fitting data with a spline, finding the optimal placement of knots can significantly improve the quality of the fit. However, the challenging high-dimensional and non-convex optimization problem associated with completely free knot placement has been a major roadblock in using this approach. We present a method that uses particle swarm optimization (PSO) combined with model selection to address this challenge. The problem of overfitting due to knot clustering that accompanies free knot placement is mitigated in this method by explicit regularization, resulting in a significantly improved performance on highly noisy data. The principal design choices available in the method …

A Simple Graphical Method For Calculating The Standing Wave Frequencies On A Rectangular Membrane, Joseph D. Romano, Richard H. Price

Physics & Astronomy Faculty Publications

In introductory physics courses, simple arguments based on traveling waves on a string are used to relate the frequency of standing waves to boundary conditions, e.g., the fixed ends of the string. Here, we extend that approach to two-dimensional waves such as the oscillations of a rectangular membrane with edges fixed at the boundary. This results in a graphical method that uses only simple geometry and is suitable for explaining two-dimensional standing-wave oscillations to non-science majors, e.g., in a physics of sound and music class.

Graphite Intercalation Compounds Derived By Green Chemistry As Oxygen Reduction Reaction Catalysts, Jianchao Zhao, Joseph H. Dumont, Ulises Martinez, Javier Macossay-Torres, Kateryna Artyushkova, Plamen Atanassov, Gautam Gupta

Physics & Astronomy Faculty Publications

Precious group metal (PGM) catalysts such as Pt supported on carbon supports are expensive catalysts utilized for the oxygen reduction reaction (ORR) due to their unmatched catalytic activity and durability. As an alternative, PGM-free ORR electrocatalysts that offer respectable catalytic activity are being pursued. Most of the notable PGM-free catalysts are obtained either from a bottom-up approach synthesis utilizing nitrogen-rich polymers as building blocks, or from a top down approach, where nitrogen and metal moieties are incorporated to carbonaceous matrixes. The systematic understanding of the origin of catalytic activity for either case is speculative and currently employed synthesis techniques typically …

A Cryogenic Silicon Interferometer For Gravitational-Wave Detection, R X. Adhikari, K. Arai, A F. Brooks, C Wipf, O Aguiar, P Altin, B Barr, L. Barsotti, R Bassiri, Volker Quetschke

Physics & Astronomy Faculty Publications

The detection of gravitational waves from compact binary mergers by LIGO has opened the era of gravitational wave astronomy, revealing a previously hidden side of the cosmos. To maximize the reach of the existing LIGO observatory facilities, we have designed a new instrument able to detect gravitational waves at distances 5 times further away than possible with Advanced LIGO, or at greater than 100 times the event rate. Observations with this new instrument will make possible dramatic steps toward understanding the physics of the nearby Universe, as well as observing the Universe out to cosmological distances by the detection of …

Quantization For A Mixture Of Uniform Distributions Associated With Probability Vectors, Mrinal Kanti Roychowdhury, Wasiela Salinas

School of Mathematical & Statistical Sciences Faculty Publications

The basic goal of quantization for probability distribution is to reduce the number of values, which is typically uncountable, describing a probability distribution to some finite set and thus approximation of a continuous probability distribution by a discrete distribution. Mixtures of probability distributions, also known as mixed distributions, are an exciting new area for optimal quantization. In this paper, we investigate the optimal quantization for three different mixed distributions generated by uniform distributions associated with probability vectors

A Single-Center Comparison Using Exoskeleton Rehabilitation For Cerebrovascular Accidents And Traumatic Brain Injury In A Cohort Of Hispanic Patients, Lisa R. Trevino, Kristina Vatcheva, Michael E. Auer, Angela Morales, Lama M. Abdurrahman, Sarajova Viswamitra, Annelyn Torres-Reveron

School of Mathematical & Statistical Sciences Faculty Publications

Background Traumatic brain injury (TBI) is one of the leading causes of disability in the United States. The EKSO GT Bionics® (EKSO®) is a robotic exoskeleton approved by the Federal Drug Administration (FDA) for rehabilitation following a cerebrovascular accident (CVA or stroke) and recently received approval for use in patients with TBI. The aim of the study was to examine if the use of exoskeleton rehabilitation in patients with TBI will produce beneficial outcomes.

Methods This retrospective chart-review reports the use of the (EKSO®) robotic device in the rehabilitation of patients with TBI compared to patients with CVA. We utilized …

Reaching 1.5 And 2.0 ◦C Global Surface Temperature Targets Using Stratospheric Aerosol Geoengineering, Simone Tilmes, Douglas G. Macmartin, Jan T. M. Lenaerts, Leo Van Kampenhout, Laura Muntjewerf, Lili Xia, Cheryl S. Harrison, Kristen M. Krumhardt, Michael J. Mills, Ben Kravitz, Alan Robock

School of Earth, Environmental, & Marine Sciences Faculty Publications

A new set of stratospheric aerosol geoengineering (SAG) model experiments has been performed with Community Earth System Model version 2 (CESM2) with the Whole Atmosphere Community Climate Model (WACCM6) that are based on the Coupled Model Intercomparison Project phase 6 (CMIP6) overshoot scenario (SSP5-34-OS) as a baseline scenario to limit global warming to 1.5 or 2.0 ◦C above 1850–1900 conditions. The overshoot scenario allows us to applying a peak-shaving scenario that reduces the needed duration and amount of SAG application compared to a high forcing scenario. In addition, a feedback algorithm identifies the needed amount of sulfur dioxide injections in …

Absence Of Landau-Peierls Instability In The Magnetic Dual Chiral Density Wave Phase Of Dense Qcd, Efrain J. Ferrer, Vivian De La Incera

Physics & Astronomy Faculty Publications

We investigate the stability of the magnetic dual chiral density wave (MDCDW) phase of cold and dense QCD against collective low-energy fluctuations of the order parameter. The appearance of additional structures in the system free energy due to the explicit breaking of the rotational and isospin symmetries by the external magnetic field play a crucial role in the analysis. The new structures stiffen the spectrum of the thermal fluctuations in the transverse direction, thereby avoiding the Landau-Peierls instability that affects single-modulated phases at arbitrarily low temperatures. The lack of Landau-Peierls instabilities in the MDCDW phase makes this inhomogeneous phase of …

Flowing With The Translanguaging Corriente: Juntos Engaging With And Making Sense Of Mathematics, Luz A. Maldonado Rodríguez, Gladys Krause, Melissa Adams Corral

Teaching and Learning Faculty Publications

The translanguaging corriente, or current of language practices, as described by García et al. (2017), is always flowing through your mathematics classroom, whether you realize it or not. The corriente, how multilinguals use all their languages to learn and engage with content in school and make sense of a complex world, requires educators to reconsider what is understood about language and mathematics. By rethinking how we view language separation in the multilingual mathematics classroom, we propose that teachers teach with a translanguaging stance in order to access multilingual students’ full linguistic repertoires and to develop deep mathematical understanding.

Optimization Of Railroad Bearing Health Monitoring System For Wireless Utilization, Jonas Cuanang, Constantine Tarawneh, Martin Amaro Jr., Jennifer Lima, Heinrich D. Foltz

Mechanical Engineering Faculty Publications

In the railroad industry, systematic health inspections of freight railcar bearings are required. Bearings are subjected to high loads and run at high speeds, so over time the bearings may develop a defect that can potentially cause a derailment if left in service operation. Current bearing condition monitoring systems include Hot-Box Detectors (HBDs) and Trackside Acoustic Detection Systems (TADS™). The commonly used HBDs use non-contact infrared sensors to detect abnormal temperatures of bearings as they pass over the detector. Bearing temperatures that are about 94°C above ambient conditions will trigger an alarm indicating that the bearing must be removed from …

The Influence Of Human Disturbance On Wildlife Use Of A Highway In South Texas, Thomas J. Yamashita

Theses and Dissertations

Roads can greatly impact wildlife. Wildlife vehicle collisions contribute to population declines while disturbance from human activity may prevent wildlife from using areas around roads. The construction of mitigation structures may lessen these effects through fine scale modification of animal use of roadside areas. In this thesis, how the construction of wildlife mitigation structures impacted the fine scale distribution of wildlife on State Highway 100 in Cameron County, Texas was examined. Spatial and temporal scale may also influence these relationships. The relationship between human activity and wildlife activity around the highway was explored and how the distribution of wildlife road …

South Texas Coastal Area Storm Surge Model Development And Improvement, Sara E. Davila, Cesar Davila Hernandez, Martin Flores, Jungseok Ho

Civil Engineering Faculty Publications

The intensification of climatic changes, mainly natural geophysical hazards like hurricanes, are of great interest to the South Texas region. Scientists and engineers must protect essential resources from coastal threats, such as storm surge. This study presents the development process and improvements of a hydrodynamic finite element model that covers the South Texas coast, specifically the Lower Laguna Madre, for the aid of local emergency management teams. Four historical tropical cyclone landfalls are evaluated and used as a means of verification of the hydrodynamic model simulation results. The parameters used to improve the accuracy of the model are the tidal …

Casimir Effect On Amplitude-Frequency Response Of Parametric Resonance Of Electrostatically Actuated Nems Cantilever Resonators, Dumitru Caruntu, Christian A. Reyes

Mechanical Engineering Faculty Publications

This paper deals with the effect of Casimir force on the amplitudefrequency response of parametric resonance of electrostatically actuated nanoresonators. The resonator is actuated by using an electrostatic force to include a f irst order fringe correction. Casimir force and viscous damping force are included in the model, as well. Both electrostatic and Casimir forces are nonlinear. The behavior of the resonator is investigated using two methods, the Method of Multiple Scales (MMS) for a Reduced Order Model (ROM) using one mode of vibration, and numerical integration of ROMs using up to five modes of vibration. ROM is based on …

The Rotational Spectrum Of 1,1-Diiodoethane, Michael Joseph Carrillo

Theses and Dissertations

The first chapter of this thesis introduces the basic theory of rotational spectroscopy. This includes the theory of a rigid rotor, centrifugal distortion, and hyperfine effects. The theory behind diatomic systems is explained first, and then expanded to the asymmetric top system. The second chapter encompasses a brief overview on the development of microwave spectroscopy and discusses the instruments that were utilized during this study, namely the cavity-based and chirped-pulse Fourier transform microwave spectrometers. Chapter three describes the quantum chemical calculation methods and basis sets that were applied throughout this study. Chapter four discusses the progress of data analysis of …

Analysis Of The Facilitative Interaction Between Batis Maritima And Avicennia Germinans As A Mangrove Restoration Strategy, Javier R. Navarro

Theses and Dissertations

The multiple experiments conducted in an Avicennia germinans forest in Laguna Vista, TX was focused on determining if facilitation theory could explain the behavior observed between the herbaceous halophyte Batis maritima and A. germinans. I hypnotized that a positive interaction exists but through which mechanisms of facilitation I did not know. The overarching theme of the study is the presence or absence of B. maritima. Facilitation theory tells us that positive interactions are most often found under stressful conditions such as those on the coastal tidal flat of the Laguna Madre. Locally B. maritima has been found to …

Using Artificial Neural Networks To Detect Astronomical Transients, Katarzyna Wardęga

Theses and Dissertations

A kilonova is an r-process-powered thermal transient created in the aftermath of a binary neutron star or black hole-neutron star merger. During these merger events, gravitational waves act as alert signals for telescopes to respond and search for potential optical counterparts. The localization probability regions for gravitational waves on the sky can be large. Additionally, kilonovae are rapidly-fading transients, making it crucial to develop an efficient method to detect them in image data. The standard method to detect transients is to subtract an image containing the plausible transient from a reference image of the same region taken at a different …

Overexpression Of Strigolactone-Associated Genes Exerts Fine-Tuning Selection On Soybean Rhizosphere Bacterial And Fungal Microbiome, Fang Liu, John Hollis Rice, Valeria Lopes, Parwinder Grewal, Sarah L. Lebeis, Tarek Hewezi, Margaret E. Staton

School of Earth, Environmental, & Marine Sciences Faculty Publications

Strigolactones are a recently discovered class of carotenoid-derived plant hormones with a wide variety of functions, including acting as signaling molecules in the rhizosphere to promote arbuscular mycorrhizal fungi colonization and parasitic seed germination. To determine whether strigolactones influence the recruitment of microbes to the rhizosphere, we characterized both bacterial and fungal communities in response to the overexpression of genes involved in strigolactone biosynthesis (MAX1d) and signaling perception (D14 and MAX2a) in soybean (Glycine max). The amplicon sequencing-based results suggest that strigolactone overexpression lines had altered soybean rhizosphere bacteria composition at both the community …

Using Genetic Diversity To Differentiate Mosquito Populations, Rachel Christine Malampy

Theses and Dissertations

Experiment 1: Little is known about Aedes aegypti females sharing oviposition sites. We examined four different oviposition sites in McAllen, TX. A mitochondrial gene was used to analyze the variation within the oviposition site to understand how many egg-laying females are sharing oviposition sites. These results will aid in the understanding of Aedes. aegypti oviposition behavior and contribute to more effective mosquito control techniques.

Experiment 2: Mosquito flight patterns and movement from habitat to habitat can drastically influence the spread of diseases. The anthropophilic Aedes aegypti mosquito has historically been identified as having a very limited flight range. Studies also …

Surface Structure And Phase Composition Of Tio2 P25 Particles After Thermal Treatments And Hf Etching, M. Jasim Uddin, Federico Cesano, Aminur Rashid Chowdhury, Tarek Trad, Sara Cravanzola, Gianmario Martra, Lorenzo Mino, Adriano Zecchina, Domenica Scarano

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

The anatase to rutile phase transformation via thermal and chemical (HF etching) routes of TiO2 P25 has been investigated. The treatment parameters and properties of the resulting anatase and rutile nanoparticles are analyzed and discussed. Since the nature of TiO2 surfaces plays a significant role in determining the physical and chemical properties of the TiO2 nanoparticles, it is important to investigate the surface properties, including the morphology, the main exposed faces, the defectiveness, to be correlated with their peculiar properties, and then reactivity. Herein, we report an infrared spectroscopy investigation, employing the adsorption of CO probe molecule at low temperature, …

Synthesis And Fabrication Of Self-Sustainable Triboelectric Energy Case For Powering Smart Electronic Devices, Abu Masa Abdullah, Alejandro Flores, Aminur Rashid Chowdhury, Jianzhi Li, Yuanbing Mao, M. Jasim Uddin

School of Integrative Biological & Chemical Sciences (Formerly Dept. of Chemistry)

In recent times, Triboelectric Nanogenerators (TENG) have attained the focus of the scientific community due to its potential as a medium to harvest mechanical energy from the ambient environment. Human motion has been attributed as a source of mechanical energy to drive electronic devices and sensors through TENG. Based on the principles of single electrode TENG, we have developed a Triboelectricity based Stepping and Tapping Energy Case (TESTEC) which magnifies the prospect to power touch electronic devices by utilizing finger tapping and stepping motion. This novel case was constructed with two single electrode TENG operating through the triboelectric mechanism between …

Absence Of Landau-Peierls Instability In The Magnetic Dual Chiral Density Wave Phase Of Dense Qcd, Efrain J. Ferrer, Vivian De La Incera

Physics & Astronomy Faculty Publications

We investigate the stability of the magnetic dual chiral density wave (MDCDW) phase of cold and dense QCD against collective low-energy fluctuations of the order parameter. The appearance of additional structures in the system free energy due to the explicit breaking of the rotational and isospin symmetries by the external magnetic field play a crucial role in the analysis. The new structures stiffen the spectrum of the thermal fluctuations in the transverse direction, thereby avoiding the Landau-Peierls instability that affects single-modulated phases at arbitrarily low temperatures. The lack of Landau-Peierls instabilities in the MDCDW phase makes this inhomogeneous phase of …

Astroalign: A Python Module For Astronomical Image Registration, Martin Beroiz, Juan B. Cabral, Bruno Sanchez

Physics & Astronomy Faculty Publications

We present an algorithm implemented in the Astroalign Python module for image registration in astronomy. Our module does not rely on WCS information and instead matches three-point asterisms (triangles) on the images to find the most accurate linear transformation between them. It is especially useful in the context of aligning images prior to stacking or performing difference image analysis. Astroalign can match images of different point-spread functions, seeing, and atmospheric conditions.