Physical Sciences and Mathematics Commons^™

The Role Of Particle Surface Functionality And Microstructure Development In Isothermal And Non-Isothermal Crystallization Behavior Of Polyamide 6/Cellulose Nanocrystals Nanocomposites, Shahram Rahimi, Joshua U. Otaigbe

Faculty Publications

Polyamide 6 (PA6)/cellulose nanocrystal (CNC) and aminopropyl triethoxy silane (APS) - modified CNC nanocomposites were prepared by in situ anionic ring opening polymerization and subsequent melt extrusion. The morphological observation of these hybrid systems revealed that the non-modified nanocrystals developed a network-like fibrillar structure while the APS-modified CNCs were finely dispersed mostly as individual whiskers. The isothermal and non-isothermal crystallization kinetics was extensively studied with emphasis on the effects of CNC surface functionality and the subsequent microstructure development on crystallization behavior of these novel nanocomposite systems. The non-modified CNC particles with corresponding fibrillar microstructure were found significantly hinder the crystallization …

Search For Dark Matter Particles In Proton-Proton Collisions At √S=8 Tev Using The Razor Variables, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, H Kalakhety, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search for dark matter particles directly produced in proton-proton collisions recorded by the CMS experiment at the LHC is presented. The data correspond to an integrated luminosity of 18.8 fb−1, at a center-of-mass energy of 8 TeV. The event selection requires at least two jets and no isolated leptons. The razor variables are used to quantify the transverse momentum balance in the jet momenta. The study is performed separately for events with and without jets originating from b quarks. The observed yields are consistent with the expected backgrounds and, depending on the nature of the production mechanism, dark matter …

Effect Of Disorder On The Magnetic And Electronic Structure Of A Prospective Spin-Gapless Semiconductor Mncrval, P. Kharel, J. Herran, Pavel Lukashev, Y. Jin, J. Waybright, S. Gilbert, B, Staten, P. Gray, S. Valloppilly, Y. Huh, D. J. Sellmyer

Faculty Work

Recent discovery of a new class of materials, spin-gapless semiconductors (SGS), has attracted considerable attention in the last few years, primarily due to potential applications in the emerging field of spin-based electronics (spintronics). Here, we investigate structural, electronic, and magnetic properties of one potential SGS compound, MnCrVAl, using various experimental and theoretical techniques. Our calculations show that this material exhibits ≈ 0.5 eV band gap for the majority-spin states, while for the minority-spin it is nearly gapless. The calculated magnetic moment for the completely ordered structure is 2.9 µ_B/f.u., which is different from our experimentally measured value of …

Greenland Subglacial Drainage Evolution Regulated By Weakly Connected Regions Of The Bed, Matthew J. Hoffman, Lauren C. Andrews, Stephen A. Price, Ginny A. Catania, Thomas A. Neumann, Martin P. Luthi, Jason Gulley, Claudia Ryser, Robert L. Hawley, Blaine Morris

Dartmouth Scholarship

Penetration of surface meltwater to the bed of the Greenland Ice Sheet each summer causes an initial increase in ice speed due to elevated basal water pressure, followed by slowdown in late summer that continues into fall and winter. While this seasonal pattern is commonly explained by an evolution of the subglacial drainage system from an inefficient distributed to efficient channelized configuration, mounting evidence indicates that subglacial channels are unable to explain important aspects of hydrodynamic coupling in late summer and fall. Here we use numerical models of subglacial drainage and ice flow to show that limited, gradual leakage of …

Deep Data Analysis On The Web, Xuanyu Liu

Master's Projects

Search engines are well known to people all over the world. People prefer to use keywords searching to open websites or retrieve information rather than type typical URLs. Therefore, collecting finite sequences of keywords that represent important concepts within a set of authors is important, in other words, we need knowledge mining. We use a simplicial concept method to speed up concept mining. Previous CS 298 project has studied this approach under Dr. Lin. This method is very fast, for example, to mine the concept, FP-growth takes 876 seconds from a database with 1257 columns 65k rows, simplicial complex only …

Predicting User's Future Requests Using Frequent Patterns, Marc Nipuna Dominic Savio

Master's Projects

In this research, we predict User's Future Request using Data Mining Algorithm. Usage of the World Wide Web has resulted in a huge amount of data and handling of this data is getting hard day by day. All this data is stored as Web Logs and each web log is stored in a different format with different Field names like search string, URL with its corresponding timestamp, User ID’s that helps for session identification, Status code, etc. Whenever a user requests for a URL there is a delay in getting the page requested and sometimes the request is denied. Our …

Handling Relationships In A Wiki System, Yashi Kamboj

Master's Projects

Wiki software enables users to manage content on the web, and create or edit web pages freely. Most wiki systems support the creation of hyperlinks on pages and have a simple text syntax for page formatting. A common, more advanced feature is to allow pages to be grouped together as categories. Currently, wiki systems support categorization of pages in a very traditional way by specifying whether a wiki page belongs to a category or not. Categorization represents unary relationship and is not sufficient to represent n-ary relationships, those involving links between multiple wiki pages.

In this project, we extend Yioop, …

Novel Concepts In Semiconductor Disk Lasers, Zhou Yang

Optical Science and Engineering ETDs

Optically-pumped semiconductor disk lasers (SDLs) have received much attention in recent years for a myriad of applications requiring intracavity access, good beam quality, wavelength versatility, and high output powers. The traditional scheme of these lasers feature a semiconductor distributed Bragg reflector (DBR) integrated with the active region, together forming an active mirror in an external free-space cavity. The active mirror component is fabricated by either epitaxial growth or post-growth processing. This places certain restrictions on SDL design, as material system choices become limited. It further viii hinders laser performance with regard to its thermal management and laser bandwidth (tuning range). …

Assessing The Impact Of A Constructed Wetland Biome On The Ecosystem Health Of Cedar Run, Thomas Vasilopoulos, Casey Lee

Senior Honors Projects, 2010-2019

A wetlands ecosystem is defined as “an area saturated by surface or groundwater at a frequency or duration sufficient to support...a prevalence of vegetation typically adapted for life in saturated soil conditions” (Batzer and Sharitz, 2007). Wetlands serve as biofilters and thus have been used to treat sewage and wastewater, as well as to restore the health of polluted water systems. Solly Walker and Lorinda Palin, owners of a certified natural and biodynamic farm called Avalon Acres located in Broadway, Virginia, constructed a wetland two years ago, using the stream, Cedar Run, that flows through their property. Pollution from agricultural …

Reintroduction Of Brook Trout To The South River Via Upwelling Springs, Sydni L. Reinhold

Senior Honors Projects, 2010-2019

Populations of brook trout, Salvelinus fontinalis, throughout Virginia mountain streams have seen a rapid decline due to warmer conditions, decreased oxygen levels, and changes in the main stem streambed (Hudy et al., 2008). Current solutions have stocked more tolerant adult brook trout in the main stem rivers, which is costly and must be repeated yearly (Lennon, 1967). Finding an environment conducive for stocking brook trout eggs rather than adults would be ideal because they would return to this viable location to spawn, making them a self-sustaining population which is less costly and easier to implement. Upwelling springs connected to the …

Impacts Of Long-Term Precipitation Manipulation On Hydraulic Architecture, Xylem Function, And Canopy Status In A Piñon-Juniper Woodland, Patrick J. Hudson

Biology ETDs

The Southwestern US is predicted to become hotter and drier, as global climate change forces increasing temperatures and variability in timing and size of precipitation inputs. Drought stress has become more frequent in recent decades, and resulted in massive forest mortality in piñon-juniper woodlands. During recent severe droughts (2000-2003, 2009-2012), piñon pine (Pinus edulis Englem.) suffered disproportionately high mortality compared to co-occurring one-seed juniper (Juniperus monosperma [Engelm.] Sarg.). A large-scale precipitation manipulation experiment was established in a piñon-juniper woodland in central New Mexico to test hypotheses regarding tree survival and mortality with respect to altered water regimes. Our …

A Scuba-2 Survey Of Felobal Qsos. Are Felobals In A ‘Transition Phase’ Between Ulirgs And Qsos?, Giulio Violino, Kristen E. K. Coppin, Jason A. Stevens, Duncan Farrah, James E. Geach, Dave M. Alexander, Ryan Hickox

Dartmouth Scholarship

It is thought that a class of broad absorption line (BAL) QSOs, characterised by Fe absorption features in their UV spectra (called `FeLoBALs'), could mark a transition stage between the end of an obscured starburst event and a youthful QSO beginning to shed its dust cocoon, where Fe has been injected into the interstellar medium by the starburst. To test this hypothesis we have undertaken deep SCUBA-2 850 μm observations of a sample of 17 FeLoBAL QSOs with 0.89 ≤ z ≤ 2.78 and -23.31 ≤ MB ≤-28.50 to directly detect an excess in the thermal emission of the dust …

Observations And Light Curve Analysis Of Transiting Extra-Solar Planets, Clark M. Holcomb

Electronic Theses and Dissertations

The purpose of this research was to perform the procedures to study transiting exoplanets in their entirety, from the data collection process to determining physical characteristics and orbital properties. The research was conducted with two telescopes of different sizes (16” and 12”) at multiple sites in order to refine the detection process. Both Maxim DL and Mira Pro x64 software were used to process the resulting images. The PHOEBE program was used to model the data to determine the properties of the exoplanets, which were then compared to the results obtained by other astronomers. The data collection process as well …

What Affects Parents’ Choice Of Milk? An Application Of Bayesian Model Averaging, Yingzhe Cheng

Mathematics & Statistics ETDs

This study identifies the factors that influence parents’ choice of milk for their children, using data from a unique survey administered in 2013 in Hunan province, China. In this survey, we identified two brands of milk, which differ in their prices and safety claims by the producer. Data were collected on parents’ choice of milk between the two brands, demographics, attitude towards food safety and behaviors related to food. Stepwise model selection and Bayesian model averaging (BMA) are used to search for influential factors. The two approaches consistently select the same factors suggested by an economic theoretical model, including price …

Geologic And Geochemical Characterization Of Cross-Communication Potential Within The Northern Edwards Aquifer System, Texas, Ingrid J. Eckhoff

Electronic Theses and Dissertations

The Edwards Aquifer is a large, complex groundwater system located throughout Central Texas in association with the Balcones Fault Zone. The San Antonio and Barton Spring segments of the Edwards Aquifer have been extensively studied in the past because they provide groundwater resources to the largely urbanized areas of San Antonio and Austin, respectively, and smaller communities along the Interstate 35 corridor. Previous research has been conducted on these southern and central portions of the Edwards Aquifer system, which have characterized the structural, hydrogeological and geochemical variations within the highly karsted region. However, the Northern Segment of the Edwards Aquifer …

Bonding Theatre And Chemistry: An Educational Exploration, Matthew Gurniak

Senior Honors Projects, 2010-2019

This paper analyzes the educational aspects of theatre and music and the impact that they have on an audience. The goal was to begin a new conversation about science and theatre and how the two can learn and gain unique insight from each other. To examine how these two antithetical fields can interact, I composed a new, innovative musical that tells the love story between two professors through the use of concepts from general chemistry. The results and responses from the performance of the play were overwhelmingly positive from members of both disciplines. They have inspired continued interest in this …

Efficient And Robust Methods For Quantum Tomography, Charles Baldwin

Physics & Astronomy ETDs

The development of large-scale platforms that implement quantum information processing protocols requires new methods for verification and validation of quantum behavior. Quantum tomography (QT) is the standard tool for diagnosing quantum states, process, and readout devices by providing complete information about each. However, QT is limited since it is expensive to not only implement experimentally, but also requires heavy classical post-processing of experimental data. In this dissertation, we introduce new methods for QT that are more efficient to implement and robust to noise and errors, thereby making QT a more widely practical tool for current quantum information experiments. The crucial …

Spectroscopic And Spectro-Astrometric Analysis Of T Tauri Stars, Logan Ryan Brown

Dissertations

To understand our own solar origins, we must investigate the composition of the protoplanetary disk from which the solar system formed. To infer this, we study analogs to the early solar system called T Tauri stars. These objects are low-mass, pre-main sequence stars surrounded by circumstellar disks of material from which planets are believed to form. We present high-resolution, near-infrared spectroscopic data for the T Tauri stars DR Tau and AA Tau using NIRSPEC at the Keck II telescope. For DR Tau, a spectro-astrometric analysis was performed, obtaining sub-seeing spatial information on water emission. Alongside a disk model, we constrained …

Quantifying Gravity Wave Momentum Fluxes With Mesosphere Temperature Mappers And Correlative Instrumentation, David C. Fritts, Pierre-Dominique Pautet, Katrina Bossert, Michael J. Taylor, Bifford P. Williams, Hiroyuki Iimura, Tao Yuan, Nicholas J. Mitchell, Gunter Stober

Publications

An Advanced Mesosphere Temperature Mapper and other instruments at the Arctic Lidar Observatory for Middle Atmosphere Research in Norway (69.3°N) and at Logan and Bear Lake Observatory in Utah (42°N) are used to demonstrate a new method for quantifying gravity wave (GW) pseudo-momentum fluxes accompanying spatially and temporally localized GW packets. The method improves on previous airglow techniques by employing direct characterization of the GW temperature perturbations averaged over the OH airglow layer and correlative wind and temperature measurements to define the intrinsic GW properties with high confidence. These methods are applied to two events, each of which involves superpositions …

The Synthesis And Characterization Of Photoluminescent Conjugated Frameworks Containing Silicon And Germanium, Douglas William Hammerstroem

Dissertations

Siloles and 9-heterofluorenes (Si, Ge) are conjugated π-electron systems containing Group 14 atoms which demonstrate unique properties such as high electron affinity, mobility, and bathochromically shifted optical spectra relative to their all-carbon analogs. This is due to their low-lying lowest-unoccupied molecular orbital (LUMO) which is resultant of the σ*-π* conjugation between the exocyclic groups at the Group 14 center and the butadiene unit of the ring. As a consequence, they have received considerable attention for their use as components for a wide variety of optical and electronic applications such as organic light emitting diodes (OLEDs), photovoltaic devices, field-effect transistors (FETs), …

Search For Dark Matter In Proton-Proton Collisions At 8 Tev With Missing Transverse Momentum And Vector Boson Tagged Jets, M M. Baarmand, Vallary Bhopatkar, Stefano Colafranceschi, Marcus Hohlmann, D Noonan, Tuhin S. Roy, Francisco X. Yumiceva, Cms Collaboration

Aerospace, Physics, and Space Science Faculty Publications

A search is presented for an excess of events with large missing transverse momentum in association with at least one highly energetic jet, in a data sample of proton-proton collisions at a centre-of-mass energy of 8 TeV. The data correspond to an integrated luminosity of 19.7 fb−1 collected by the CMS experiment at the LHC. The results are interpreted using a set of simplified models for the production of dark matter via a scalar, pseudoscalar, vector, or axial vector mediator. Additional sensitivity is achieved by tagging events consistent with the jets originating from a hadronically decaying vector boson. This search …

Ionospheric Signatures Of Gravity Waves Produced By The 2004 Sumatra And 2011 Tohoku Tsunamis: A Modeling Study, Michael P. Hickey, Yonghui Yu, Wenqing Wang

Publications

Ionospheric fluctuations inferred from observations of total electron content have previously been attributed to tsunamis and have confirmed the strong coupling between Earth’s ocean and ionosphere via atmospheric gravity waves (AGWs). To further advance our understanding of this wave coupling process we employ a linear full-wave model and a nonlinear time-dependent model to examine the ionospheric response to the AGW perturbations induced by the 2004 Sumatra and the 2011 Tohoku tsunamis. In the 2004 case, our modeling analyses reveal that one component of the propagating AGWs becomes dynamically unstable in the E-region ionosphere at a range exceeding 2000 km in …

An Investigation Into The Origin, Composition, And Commercial Significance Of A Sedimentary Subsalt Formation: Keathley Canyon, Gulf Of Mexico, David Aaron Brassieur

LSU New Orleans Theses and Dissertations

Sub-salt oil and gas formations in deep-water northern Gulf of Mexico are high priority targets. Advances in seismic processing allow for high-resolution, below-salt imaging. Understanding the modes of salt emplacement provide insight into sub-salt traps and potential drilling hazards.

A sub-salt sedimentary unit lies in the Keathley Canyon protraction. Autosutures created the transport-parallel lineaments of the upper surface of the unit. In addition, highly variable sediment aggradation rates created ramps, flats, and basal cutoffs along the base of the allochthon as salt and sediment competed for space. Seismic models identify modes of salt emplacement, salt/sediment interactions, and mechanisms responsible for …

A Machine Learning Approach To Determine Oyster Vessel Behavior, Devin Frey

LSU New Orleans Theses and Dissertations

A support vector machine (SVM) classifier was designed to replace a previous classifier which predicted oyster vessel behavior in the public oyster grounds of Louisiana. The SVM classifier predicts vessel behavior (docked, poling, fishing, or traveling) based on each vessel’s speed and either net speed or movement angle. The data from these vessels was recorded by a Vessel Monitoring System (VMS), and stored in a PostgreSQL database. The SVM classifier was written in Python, using the scikit-learn library, and was trained by using predictions from the previous classifier. Several validation and parameter optimization techniques were used to improve the SVM …

Effect Of Small-Scale Continental Shelf Bathymetry On Storm Surge Generation, Sunni A. Siqueira

LSU New Orleans Theses and Dissertations

Idealized bathymetries were subjected to idealized cyclones in order to measure the storm surge response to a range of bathymetry features, under various storm conditions. Ten bathymetries were considered, including eight shoals, one pit, and a featureless reference domain. Six storms (two different sizes/intensities and three different landfall directions) were used as meteorological forcing. The bathymetry features influenced local surge response during pre- and post-peak surge conditions. However, peak surge and surge at the coast were not meaningfully affected by the presence of the bathymetry features considered. The effect of three bathymetry feature parameters on surge response was analyzed (i.e. …

Biloxi Marsh Platform Response Due To Meteorological Forcing, Rachelle Thomason

LSU New Orleans Theses and Dissertations

The Biloxi Marsh of the eastern Mississippi River delta plain is exposed to meteorological forces ranging from large-scale, mid-latitude cyclones to smaller scale storms and squalls. Each time that these marsh platforms are exposed to a storm event, the potential exists for either deposition or erosion to take place. This study examines the connection between wind speeds, stratigraphic composition, marsh edge morphology, and marsh edge erosion at 4 sites in the Biloxi Marsh. As much as 2.17 m of erosion were measured during the 9-month study with a maximum, averaged erosion rate of 0.03 m day^-1. Shell berm …

Spatial Data Mining Analytical Environment For Large Scale Geospatial Data, Zhao Yang

LSU New Orleans Theses and Dissertations

Nowadays, many applications are continuously generating large-scale geospatial data. Vehicle GPS tracking data, aerial surveillance drones, LiDAR (Light Detection and Ranging), world-wide spatial networks, and high resolution optical or Synthetic Aperture Radar imagery data all generate a huge amount of geospatial data. However, as data collection increases our ability to process this large-scale geospatial data in a flexible fashion is still limited. We propose a framework for processing and analyzing large-scale geospatial and environmental data using a “Big Data” infrastructure. Existing Big Data solutions do not include a specific mechanism to analyze large-scale geospatial data. In this work, we extend …

The Role Of The Unusual Threonine String In The Conversion Of Prion Protein, Romany Abskharon, Fei Wang, Kayla J. Vander Stel, Kumar Sinniah

University Faculty Publications and Creative Works

The conversion of normal prion protein (PrP) into pathogenic PrP conformers is central to prion disease, but the mechanism remains unclear. The α-helix 2 of PrP contains a string of four threonines, which is unusual due to the high propensity of threonine to form β-sheets. This structural feature was proposed as the basis for initiating PrP conversion, but experimental results have been conflicting. We studied the role of the threonine string on PrP conversion by analyzing mouse Prnpa and Prnpb polymorphism that contains a polymorphic residue at the beginning of the threonine string, and PrP mutants in which threonine 191 …

Mechanistic Plug-And-Play Models For Understanding The Impact Of Control And Climate On Seasonal Dengue Dynamics In Iquitos, Peru, Nathan Levick

Mathematics & Statistics ETDs

Dengue virus is a mosquito-borne multi-serotype disease whose dynamics are not precisely understood despite half of the world’s human population being at risk of infection. A recent dataset of dengue case reports from an isolated Amazonian city— Iquitos, Peru—provides a unique opportunity to assess dengue dynamics in a simpli- fied setting. Ten years of clinical surveillance data reveal a specific pattern: two novel serotypes, in turn, invaded and exclusively dominated incidence over several seasonal cycles, despite limited intra-annual variation in climate conditions. Together with mechanistic mathematical models, these data can provide an improved understand- ing of the nonlinear interactions between …

A Green Oasis: What Makes Community Gardens Worth Saving? While Researchers Amass Evidence Of Benefits, Advocates Develop New Strategy To Prove Their Value., Joel Wolfram

Capstones

Green Valley Community Garden in Brownsville, Brooklyn, is one of about a dozen gardens on land owned by the New York City Department of Housing Preservation and Development that are being uprooted by plans to build affordable housing. The gardeners are fighting back to prevent the garden’s destruction, saying that the food-producing green space is a source of healthy eating in a community with high rates of health problems, like diabetes and obesity. Researchers are attempting to tease out the public health benefits of community gardens as one metric of their value, but the science is still catching up with …