Physical Sciences and Mathematics Commons^™

Fluoride And Phosphate Glass Whispering Gallery Micro-Resonators, Jonathan Ward

Theses

This PhD work focuses on spherical microlasers made from commercial and experimental laser glasses. The laser light in a microsphere is confined in a region called a whispering gallery mode, which has unique properties that allow for many nonlinear effects to be observed with only sub-mW pump powers. Efficient coupling of light into the microsphere is attained by using adiabatically tapered fibres fabricated using various heating methods including a CO₂ laser, a sapphire tube furnace and electric heaters. However, the best result is obtained using a fibre pulling rig with an oxy-butane torch as the heat source. This system …

The Geometry Of The Space Of Oriented Geodesics Of Hyperbolic 3-Space, Nikos Georgiou

Theses

In this thesis we construct a Kähler structure (J, Ω, G) on the space L(H³) of oriented geodesics of hyperbolic 3-space H³ and investigate its properties. We prove that (L(H³),J) is biholomorphic to (see thesis pdf), and that the Kähler metric G is of neutral signature, conformally flat and scalar flat.

We establish that the identity component of the isometry group of the metric G on L(H³) is isomorphic to the identity component of the hyperbolic isometry group. We show that the geodesics of G correspond to ruled minimal surfaces in H3, which …

Holographic Recording In Acrylamide Photopolymers: Thickness Limitations, Mohammad Mahmud, Izabela Naydenova, Nitesh Pandey, Tzvetanka Babeva, Raghavendra Jallapuram, Suzanne Martin, Vincent Toal

Articles

Holographic recording in thick photopolymer layers is important for application in holographic data storage, volume holographic filters and correlators. Here, the characteristics of acrylamidebased photopolymer layers having thickness from 250 μm to 1-mm were studied. For each layer thickness samples with three different values of absorbance were studied. By measuring both the first order diffraction efficiency growth of holographically recorded gratings and studying the diffraction patterns obtained, the influence of scattering on the diffraction efficiency of thick volume holographic gratings was analyzed. It was observed that above a particular thickness and absorbance, the first order diffraction efficiency significantly decreased because …

Out-Of-Plane Vibration Analysis With A Transmission Holographic Optical Element Based Electronic Speckle Pattern Interferometer, Viswanath Bavigadda, Vincent Toal, Raghavendra Jallapuram, Emilia Mihaylova

Conference Papers

A simple electronic speckle pattern interferometer (ESPI) using a transmission holographic optical element (THOE) is presented. The THOE is designed to create a speckled reference beam in the interferometer. It is a transmission hologram of a diffusely transmitting glass plate A specific requirement for the fabrication of the THOEs is for them to be recorded at one wavelength at which the recording material is photosensitive and reconstructed using a near infrared laser diode which can be current modulated for phase shifting purposes. A partially reflective glass plate provides illumination of the object along the normal to its surface, ensuring that …

Holographic Recording In Charged Photopolymerisable Nanocomposites, Temenujka Yovcheva, Ivanka Vlaeva, Simeon Sainov, Izabela Naydenova, Vincent Toal, Svetlana Mintova

Conference Papers

Self – processing photopolymers have a large number of different applications due to their versatile properties as holographic recording materials. A significant effort has been directed towards the development of photopolymers for holographic data storage [1, 2], holographic sensors [3], holographic optical elements [4] and display holograms [5]. The Centre for Industrial and Engineering Optics has been developing acrylamide based photopolymers for the last decade [6-8]. The main parameters requiring improvement in these types of photopolymers are their dynamic range and their mechanical stability during the holographic recording. Recently we have successfully used zeolite nanoparticles as dopants in order to …

Recent And Emerging Applications Of Holographic Photopolymers And Nanocomposites, Izabela Naydenova, Pavani Kotakonda, Raghavendra Jallapuram, Tsvetanka Babeva, Denis Bade, Suzanne Martin, Vincent Toal, Svetlana Mintova

Conference Papers

Sensing applications of holograms may be based on effects such as change in the spacing of the recorded fringes in a holographic diffraction grating in the presence of an analyte so that the direction of the diffracted laser light changes, or, in the case of a white light reflection grating, the wavelength of the diffracted light changes. An example is a reflection grating which swells in the presence of atmospheric moisture to indicate relative humidity by a change is the colour of the diffracted light. These devices make use of the photopolymer’s ability to absorb moisture. In a more versatile …

A Test Battery Approach To The Ecotoxicological Evaluation Of Cadmium And Copper Employing A Battery Of Marine Bioassays, Ailbhe Macken, Michelle Giltrap, Kim Ryall, Barry Foley, Evin Mcgovern, Brendan Mchugh, Maria Davoren

Articles

The main aim of this study was to investigate the sensitivity of the battery to two recognised metal pollutants of the marine environment and rank species sensitivity accordingly.

Influence Of Magnesium Nitrate On The Corrosion Performance Of Sol-Gel Coated Aa2024-T3 Aluminium Alloy, Rajath Varma, Brendan Duffy, John Cassidy

Articles

Traditional anti-corrosion technology has relied heavily on using reducible metal species, predominantly hexavalent chromium (Cr(VI)), for protecting reactive metal alloys such as aluminium which is extensively used in the aerospace sector. However, the impending changes in the use of Cr(VI) in Europe and the United States have forced aerospace manufacturers to examine alternative materials for protecting aluminium. One of the most promising alternatives being investigated are organosilane based sol-gels containing anticorrosion additives. In this work the anti-corrosion properties of magnesium (II) nitrate (Mg(NO3)2) as a inhibitor was investigated at different concentrations (0.1% - 1.0 wt %) in a methyltriethoxysilane (MTEOS) …

Silver Doped Perfluoropolyether-Urethane Coatings: Antibacterial Activity And Surface Analysis, Niall Stobie, Brendan Duffy, Steven Hinder, Patrick Mchale, Declan Mccormack

Articles

The colonisation of clinical and industrial surfaces with pathogenic microorganisms has prompted increased research into the development of effective antibacterial and antifouling coatings. There is evidence that implanted biomedical surfaces coated with metallic silver can be inactivated by hysiological fluids, thus reducing the bioactivity of the coating. In this work, we report the biofilm inhibition of Staphylococcus epidermidis using a roomtemperatureprocessedsilver dopedperfluoropolyether-urethane coating. The release of silver ions from these fluoropolymers over a six-day period inhibited bacterial encrustation – as observed by scanning electron microscopy (SEM). X-ray photoelectron spectroscopy (XPS) analysis indicated differences in carbon, fluorine and sodium surface composition …

Structural Basis For Binding Specificity Between Subclasses Of Modular Polyketide Synthase Docking Domains, Tonia Buchholz, Todd W. Geders, Frank E. Bartley Iii, Kevin A. Reynolds, Janet L. Smith, David H. Sherman

Chemistry Faculty Publications and Presentations

Bacterial type I polyketide synthases (PKSs) assemble structurally diverse natural products of significant clinical value from simple metabolic building blocks. The synthesis of these compounds occurs in a processive fashion along a large multiprotein complex. Transfer of the acyl intermediate across interpolypeptide junctions is mediated, at least in large part, by N- and C-terminal docking domains. We report here a comprehensive analysis of the binding affinity and selectivity for the complete set of discrete docking domain pairs in the pikromycin and erythromycin PKS systems. Despite disconnection from their parent module, each cognate pair of docking domains retained exquisite binding selectivity. …

A Photochemically Initiated Chemistry For Coupling Underivatized Carbohydrates To Gold Nanoparticles, Xin Wang, Olof Ramström, Mingdi Yan

Chemistry Faculty Publications and Presentations

The sensitive optoelectronic properties of metal nanoparticles make nanoparticle-based materials a powerful tool to study fundamental biorecognition processes. Here we present a new and versatile method for coupling underivatized carbohydrates to gold nanoparticles (Au NPs) via the photochemically induced reaction of perfluorophenylazide (PFPA). A one-pot procedure was developed where Au NPs were synthesized and functionalized with PFPA by a ligand-exchange reaction. Carbohydrates were subsequently immobilized on the NPs by a fast light activation. The coupling reaction was efficient, resulting in high coupling yield as well as high ligand surface coverage. A colorimetric system based on the carbohydrate-modified Au NPs was …

Gorenstein Flat Dimension Of Complexes, Alina Iacob

Mathematical Sciences: Faculty Publications

We define a notion of Gorenstein flat dimension for unbounded complexes over left GF-closed rings. Over Gorenstein rings we introduce a notion of Gorenstein cohomology for complexes; we also define a generalized Tate cohomology for complexes over Gorenstein rings, and we show that there is a close connection between the absolute, the Gorenstein and the generalized Tate cohomology.

On Fourier Parabolic And Wave Equation, Mekki Terbeche, Broderick O. Oluyede

Mathematical Sciences: Faculty Publications

This paper is devoted to a diffusion (heat) and wave equations for the function of two independent variables. We establish a criterion for existence and uniqueness of the solution of Fourier parabolic equation using Taylor series. A formal solution for a wave equation is investigated.

On Some Differential Equations, Mekki Terbeche, Broderick O. Oluyede

Mathematical Sciences: Faculty Publications

This paper investigates Cauchy and Goursat problems for partial differential operators. Successive approximation techniques for partial differential equations and the estimated results are employed to obtain the existence and the uniqueness of the solutions of such problems. An extended Darboux-Goursat-Beudon problem is studied.

Combinatorics Of Ramanujan-Slater Type Identities, James Mclaughlin, Andrew Sills

Mathematical Sciences: Faculty Publications

We provide the missing member of a family of four q-series identities related to the modulus 36, the other members having been found by Ramanujan and Slater. We examine combinatorial implications of the identities in this family, and of some of the identities we considered in Identities of the Ramanujan-Slater type related to the moduli 18 and 24.

Establishment Of Weak Conditions For Darboux-Goursat-Beudon Theorem, Mekki Terbeche, Broderick O. Oluyede

Mathematical Sciences: Faculty Publications

This paper is devoted to the establishment of weak conditions for Darboux-Goursat-Beudon (DGB) theorem in order to improve analogous results in [1, 7]. By adapting a technique proposed by [7] in another setting [8] via majorant method, we obtain the generalization of DGB theorem.

Proceedings Of The Third Annual Meeting Of The Georgia Association Of Mathematics Teacher Educators Front Matter

Proceedings of the Annual Meeting of the Georgia Association of Mathematics Teacher Educators

Contents of 3rd Annual GAMTE Proceedings Front Matter:

• Proceedings Committee
• Officers of GAMTE
• Purposes and Goals of GAMTE
• Table of Contents
• Letter from President

Analysis Of Achievement For Understanding Geometry, Annita W. Hunt

Proceedings of the Annual Meeting of the Georgia Association of Mathematics Teacher Educators

The purpose of this study was to investigate the effectiveness of a mathematics professional development course. More specifically, in this study we examine whether geometric experiences have an impact on level of performance in mathematics. The van Hiele (Fuys, D., Geddes, D., & Tischler, R., 1988) model of geometric understanding provided a research framework from which to view geometric understanding. This model suggests five levels of understanding that should be taken into consideration when examining levels of geometric thinking: Visual, Descriptive/Analytic, Abstract/Relational, Formal Deduction/Proof, and Rigor. The sample under study was three cohorts of practicing elementary teachers and mathematics coaches …

Content Knowledge And Pedagogical Content Knowledge Of Algebra Teachers And Changes In Both Types Of Knowledge As A Result Of Professional Development, Joy W. Black

Proceedings of the Annual Meeting of the Georgia Association of Mathematics Teacher Educators

In seeking to improve the mathematics education of all students, it is important to understand the connection between the content knowledge and pedagogical content knowledge of mathematics and how professionals can influence growth in both of these types of knowledge. We do not have an answer about the interplay of content knowledge and pedagogical content knowledge in successful instructional practices in the mathematics classroom. This study involves assessing the content knowledge and pedagogical content knowledge of secondary teachers of Algebra I. In addition, how are these types of knowledge expressed in instructional practices? Last, how do content knowledge, pedagogical content …

Authentic Discovery Projects In Statistics, Dianna J. Spence, Robb Sinn

Proceedings of the Annual Meeting of the Georgia Association of Mathematics Teacher Educators

We report the activities and findings of a 3-year project, ―Authentic, Career-Specific, Discovery Learning Projects in Introductory Statistics,‖ funded by the National Science Foundation. The project scope includes: 1) development of teaching materials for using discovery learning projects to teach statistics; 2) training secondary teachers to use the materials developed; 3) evaluation of student outcomes, in both content knowledge and attitudes toward statistics; and 4) extending and refining teacher training. With input from an interdisciplinary team of instructors, materials were developed to assist the teacher in facilitating collaborative discovery projects using linear regression techniques and comparison techniques with appropriate t-tests. …

Scanning Probe Microscopy Investigations Of (1) Arrays Of Cysteine-Coated Cds Nanoparticles And (2) Structures Formed During The Early Stages Of The Corrosion Of Copper Surfaces, Brian Robert Lewandowski

LSU Doctoral Dissertations

Scanning probe microscopy (SPM) characterizations are becoming more prevalent for surface investigations due to their capabilities for obtaining structural information and physical measurements. New capabilities of SPM for studying and controlling nanoscale processes are emerging as valuable assets in research. A fundamental understanding of the interactions of surface reactions provides essential information for developing workable applications for nanotechnology. Two applications of SPM are discussed in this dissertation. The first investigation uses atomic force microscopy (AFM) for the characterization of nanostructures produced with a newly developed lithographic technique called “two-particle” lithography. This new technique is based on particle lithography for the …

The Informational Content Of Canonical Disjoint Np-Pairs, Christian Glaßer, Alan L. Selman, Liyu Zhang

Computer Science Faculty Publications

We investigate the connection between propositional proof systems and their canonical pairs. It is known that simulations between propositional proof systems translate to reductions between their canonical pairs. We focus on the opposite direction and study the following questions.

Q1: For which propositional proof systems f and g does the implication hold, and for which does it fail?

Q2: For which propositional proof systems of different strengths are the canonical pairs equivalent?

Q3: What do (non-)equivalent canonical pairs tell about the corresponding propositional proof systems?

Q4: Is every NP-pair (A, B), where A is NP-complete, strongly many-one equivalent to the …

Storage, Manipulation, And Visualization Of Lidar Data, Bianca Schoen-Phelan, M. Bertolotto, D. F. Laefer, Sean W. Corish

Conference papers

In recent years, three-dimensional (3D) data has become increasingly available, in part as a result of significant technological progresses in Light Detection and Ranging (LiDAR). LiDAR provides longitude and latitude information delivered in conjunction with a GPS device, and elevation information generated by a pulse or phase laser scanner, which together provide an effective way of acquiring accurate 3D information of a terrestrial or manmade feature. The main advantages of LiDAR over conventional surveying methods lie in the high accuracy of the data and the relatively little time needed to scan large geographical areas. LiDAR scans provide a vast amount …

Toward Social Search: From Explicit To Implicit Collaboration To Predict Users' Interests, Luca Longo, Stephen Barrett

Conference papers

Inspection methods and cheap self-reporting procedures have been significantly employed in the field of Human- Computer Interaction for assessing the usability of interfaces, systems and technologies. However, there is a tendency to overlook aspects related to the context and features of the users during the usability assessment process. This research introduces the concept of mental workload as an aid to enhance usability measurement. A user-study has been designed and executed in the context of human-web interaction. The aim was to investigate the relationship between the perception of usability of three popular web-sites, and the mental workload imposed by a set …

Enabling Adaptation In Trust Computations, Luca Longo, Pierpaolo Dondio, Bresciani Riccardo, Andrew Butterfield, Stephen Barrett

Conference papers

Digital systems have been rapidly evolving within highly dynamic and unstructured environments, where the lack of a central authority forces entities to interact with each other through collaboration and negotiation. Digital agents often use Trust models in order to compute the level of trustworthiness of the partner they want to collaborate with. Unfortunately, due to the evolution speed of open and collaborative environments, the trustworthiness of an agent varies over time, and as a result, Trust models must be continuously adapted to the changing context. In this work we address the problem by presenting a self-adaptive model for Trust computations. …

Fabrication Of Nanostructured Surfaces With Well-Defined Chemistry Using Particle Lithography, Jie-Ren Li

LSU Doctoral Dissertations

Natural self-assembly processes provide nanofabrication capabilities for designing surfaces with nanoscale control of surface chemistry and relative orientation of the nanomaterials on the surfaces. Particle lithography was used to produce periodic arrays of protein nanostructures. Monodisperse mesoparticles can be applied to rapidly prepare millions of uniform protein nanostructures on flat surfaces using the conventional benchtop chemistry steps of mixing, centrifuging, evaporation and drying. Nanopatterns of bovine serum albumin and staphylococcal protein A were produced with particle lithography. The immobilized proteins remain attached to the surface and form nanopatterns over micron areas corresponding to the thickness of a single layer of …

Proxy Records Of Paleohurricanes For The Western And Southern Caribbean, Terrence Allen Mccloskey

LSU Doctoral Dissertations

This dissertation evaluates the hypothesis that hurricane activity levels in the North Atlantic during the late Holocene have been driven by latitudinal movements of the North Atlantic circulation system. Multi-millennial sedimentary proxy records, based on the occurrence of overwash clastic layers, provide clear evidence of abruptly alternating periods of hurricane landfall frequency for Nicaragua and Belize. Three Belizean transects exhibit an Active period (hyperactivity) occurring from ~2000-6000 cal yr BP, although dating is inconsistent across the transects. An Active period covering the last 500 years is found at one location. The Nicaraguan record, derived from three transects covering >90 km …

Peptide Targeting Of Platinum Anti-Cancer Drug And Synthesis Of Water Soluble Monofunctional Pt(Ii) Complexes Useful For Biological Labeling, Margaret W. Ndinguri

LSU Doctoral Dissertations

Platinum has been used as an inorganic medicinal agent with various applications such as anti cancer agents. Several new targeted Pt(II) conjugates were synthesized having the NGR and LHRH targeting motif. The platinum conjugates bearing the NGR motif revealed selective delivery and destruction of cancer cells that had CD13 receptors compared to untargeted carboplatin drug. The development of targeted chemotherapeutic has opened a new approach for efficient delivery of antitumor toxins with minimal exposure to normal cells. Several peptide sequences are known to have the ability to target tumors, for instance NGR motif which home specifically in solid tumors and …

Sampling With Confidence: Using K-Nn Confidence Measures In Active Learning, Rong Hu, Sarah Jane Delany, Brian Macnamee

Conference papers

Active learning is a process through which classifiers can be built from collections of unlabelled examples through the cooperation of a human oracle who can label a small number of examples selected as most informative. Typically the most informative examples are selected through uncertainty sampling based on classification scores. However, previous work has shown that, contrary to expectations, there is not a direct relationship between classification scores and classification confidence. Fortunately, there exists a collection of particularly effective techniques for building measures of classification confidence from the similarity information generated by k-NN classifiers. This paper investigates using these confidence measures …

Forked:A Demonstration Of Physics Realism In Augmented Reality, David Beaney, Brian Mac Namee

Conference papers

In making fully immersive augmented reality (AR) applications, real and virtual objects will have to be seen to physically interact together in a realistic and believable way. This paper describes Forked! a system that has been developed to show how physical interactions between real and virtual objects can be simulated re- alistically and believably through appropriate use of a physics en- gine. The system allows users control a robotic forklift to manipu- late virtual crates in an AR environment. The paper also describes a evaluation experiment in which it is shown that the physical inter- actions between the forklift and …