Physical Sciences and Mathematics Commons^™

Photochemical Studies Of Nutraceuticals In The Presence Of Cyclodextrins, Zlata Tofzikovskaya, Christine O'Connor, Mary Mcnamara

Conference Papers

The photostability studies of Folic acid and Menadione Sodium Bisulfite, also known as vitamin K3, were carried out in their aqueous solutions at room temperature. Solutions of Folic acid ( 4.8 x 10-5 M) and Menadione Sodium Bisulfite (4.0 x 10-4 M) were exposed to ultraviolet radiation at a wavelength of 365 nm. During exposure absorbance of both solutions was measured using a Perkin Elmer Lamda 900 UV/VIS/NIR Spectrometer. During the stability tests it was noted that addition of β Cyclodextrin (1:1 ratio) to aqueous solutions containing the vitamin slowed down the photodegradation process. The unique shape of Cyclodextrins allows …

Luminescent Solar Concentrators: A Review Of Recent Results, Wilfrid G.J.H.M. Van Sark, Keith W.J. Barnham, Lenneke H. Slooff, Amanda J. Chatten, Andreas Buchtemann, Andreas Meyer, Sarah Mccormack, Rolf Koole, Daniel J. Farrell, Rahul Bose, Evert E. Bende, Antonius R. Burgers, Tristram Budel, Jana Quilitz, Manus Kennedy, Toby Meyer, C. De Mello Donega, Andries Meijerink

Articles

Luminescent solar concentrators (LSCs) generally consist of transparent polymer sheets doped with luminescent species. Incident sunlight is absorbed by the luminescent species and emitted with high quantum efficiency, such that emitted light is trapped in the sheet and travels to the edges where it can be collected by solar cells. LSCs offer potentially lower cost per Wp. This paper reviews results mainly obtained within the framework of the Fullspectrum project. Two modeling approaches are presented, i.e., a thermodynamic and a ray-trace one, as well as experimental results, with a focus on LSC stability.

Application Of The Fractal Market Hypothesis For Modelling Macroeconomic Time Series, Jonathan Blackledge

Articles

This paper explores the conceptual background to financial time series analysis and financial signal processing in terms of the Efficient Market Hypothesis. By revisiting the principal conventional approaches to market analysis and the reasoning associated with them, we develop a Fractal Market Hypothesis that is based on the application of non-stationary fractional dynamics using an operator of the type
∂² / ∂x² − σ^q(t) * ∂ ^q(t)/ ∂t^q(t)

where σ⁻¹ is the fractional diffusivity and q is the Fourier dimension which, for the topology considered, (i.e. the one-dimensional case) is related to the Fractal …

Covert Encryption And Document Authentication Using Texture Coding, Jonathan Blackledge, Mary Hallot

Articles

With the improvements in the quality of Commercial-Off-The-Shelf (COTS) printing and scanning devices, the ability to counterfeit documents has become a widespread problem. Consequently, there has been an increasing demand to develop digital watermarking techniques which can be applied to both electronic and printed images (and documents) that can be authenticated, prevent unauthorized copying and withstand abuse and degradation. In this paper , a new approach to digital watermarking is presented and a range of possible applications are considered. The process is defined by using concepts and techniques borrowed from Cryptography. It is based on computing a 'scramble image' by …

A Study Of Boundary Layer Fflow With No-Slip And Slip Boundary Conditions, Sandra B. Spillane

Doctoral

This thesis involves solving the two-dimensional boundary layer equations for axially symmetric fluid flow along a circular cylinder using the no-slip and slip boundary condition, and along a flat plate with the slip boundary condition. Initially, historical results in both areas are summarised. The research section of this thesis is concerned with extending these historical results. In the first research chapters, a Pade approximation and an Euler transformation are used to greatly extend the region of validity of the historical results. Following that is an investigation of the relaxation of the traditional no-slip boundary condition, which usually occurs when there …

Implementation Of Phase-Only Modulation Utilizing A Twisted Nematic Liquid Crystal Spatial Light Modulator, Mohammad Mahmud, Izabela Naydenova, Vincent Toal

Articles

Twisted nematic liquid crystal spatial light modulators, (SLM) are widely used for amplitude modulation of light. The technique for measuring phase and amplitude modulation introduced by a twisted nematic cell is not new but the novelty here is that after characterisation of a Holoeye LC2002 TNLC device we were able to identify specific conditions that allow for its use as a pure 180 degree or more, phase modulator with little or no amplitude modulation at 514.5 nm laser wavelength. The phase shift introduced by the SLM was measured using a Mach-Zehnder interferometer. The experimentally measured and the theoretically predicted intensity …

Hoe-Based Espi Systems, Emilia Mihaylova, Viswanath Bavigadda, Raghavendra Jallapuram, Vincent Toal

Conference Papers

Electronic speckle pattern interferometry (ESPI) is a full-field measurement technique, capable of displaying vibrational mode shapes. Two electronic speckle pattern interferometers using reflection holographic optical elements (RHOEs) are presented. In the first ESPI system the RHOE is designed to create the speckled reference beam. A partially reflective glass plate provides illumination of the object along the normal to its surface, ensuring that the system is sensitive only to out-of-plane displacement of the object. It is demonstrated that the HOE-based system can be used for vibration measurements. Phase shifting can be implemented for fringe analysis. In the second ESPI system a …

Development And Evaluation Of Passive Sampling And Lc-Ms Based Techniques For The Detection And Monitoring Of Lipophilic Marine Toxins In Mesocosm And Field Studies, Elie Fux

Doctoral

The consumption of shellfish that accumulate marine biotoxins produced by harmful Algae can result in severe gastrointestinal or neurotoxic illnesses depending on the nature of the toxin. Therefore, it is essential that suitable monitoring programs are implemented in order to protect public health. This PhD study focused on aspects of the characteristics and monitoring of azaspiracids and toxins from Dinophysis spp. Passive samplers were used in this study in parallel with both indigenous and transplanted mussels that did not contain toxins to investigate the accumulation of toxins on the West coast of Ireland during 2005. This approach allowed for a …

Systematic Synthesis And Study Of The Structure-Property Relationships Of Arylene Vinylene Polymers., Patrick Lynch

Doctoral

Much is known about the electronic, vibrational and steric effects resulting from the addition of differing organic functional groups as side chains, to the parent conjugated polymer. However the same cannot be said about the substitution of constituents of the polymer backbone itself. To this end a study is presented here which systematically studies the effects of naphthalene and anthracene substitution of the properties of poly phenylene vinylene (PPV) derivative conjugated polymers. The synthesis by the Witting-Horner reaction of derivatives is presented whereby the phenylene units of the PPV structure are methodically substituted by naphthylene and anthrylene units to form …

Novel Photoelectrochemical Cell For The Remediation Of Organic Compounds In Water, Patrick Enright

Doctoral

Titanium dioxide (TiO2) suspensions have widely been used as photocatalysts, either alone or in a doped form to degrade organic compounds and kill bacteria. Because of its relatively large band gap, UV light has been the most efficient radiation used to allow this catalysis to occur. TiO2 has also been immobilised on electrodes in order to separate the ‘reduction’ and ‘oxidation’ reactions. Typical systems involve the oxidation of a ‘fuel’ at a TiO2 coated anode and the reduction of oxygen at a separate cathode, where the passage of current can be monitored, and this work utilises such a system. In …

Digital Close Range Photogrammetry In Motor Vehicle Accident Reconstruction, Fiona Coyle

Doctoral

Road traffic accidents are consistently in the top ten causes of death world-wide. In order to reduce the number of fatalities caused by traffic collision, better knowledge and understanding of the sequence of events prior to and during a traffic accident, i.e. Accident Reconstruction, is required, so it is important to obtain detailed quantitative information about the damage sustained by the crashed vehicle(s). The research reported here was aimed at developing a fast and accurate method of measuring the damage. Digital Close Range Photogrammetry is the technique chosen for obtaining vehicle profiles from which accurate measurements of crust damage could …

Investigation Of The Electronic Properties Of Organic Systems Using Electroabsorption Spectroscopy, Garrett F. Farrell

Doctoral

The aim of this project is to investigate the effect of bulk structural modification on the electronic properties of fullerene systems as measured using electronic and Electroabsorption (EA) spectroscopy. The existence of a unique solid state feature in C60 is the first indication that the material’s electronic properties may be influenced by its crystalline environment and as such merits investigation. The nature and extent of these interactions in the solid state is still unclear, in particular whether the molecular electrons remain located on the individual molecules or whether they are delocalised across the solid. The extent of these interactions has …

Referring Expression Generation Challenge 2008 Dit System Descriptions (Dit-Fbi, Dit-Tvas, Dit-Cbsr, Dit-Rbr, Dit-Fbi-Cbsr, Dit-Tvas-Rbr), John D. Kelleher, Brian Mac Namee

Conference papers

This papers desibes a set of systems developed at DIT for the Referring Expression Generation challenage at INLG 2008.In Proceedings of the 5th International Natural Language Generation Conference (INLG-08)

Volcanic Activity: Processing Of Observation And Remote Sensing Data (Vapor), Mark Wylie

Reports

The World Bank makes a very clear distinction between disasters and natural phenomena. Natural phenomena are events like volcanic eruptions. A disaster only occurs when the ability of the community to cope with natural phenomenon has been surpassed, causing widespread human, material, economic or environmental losses. By these definitions, volcanic eruptions do not have to lead to disasters. On November 13, 1985, the second most deadly eruption of the twentieth century occurred in Colombia. Within a few hours of the eruption of the Nevado del Ruiz volcano, 23,000 people were dead because no infrastructure existed to respond to such an …

Medical Language Processing For Patient Diagnosis Using Text Classification And Negation Labelling, Brian Mac Namee, John D. Kelleher, Sarah Jane Delany

Conference papers

This paper describes the approach of the DIT AIGroup to the i2b2 Obesity Challenge to build a system to diagnose obesity and related co-morbidities from narrative, unstructured patient records. Based on experimental results a system was developed which used knowledge-light text classification using decision trees, and negation labelling.

A Translation Mechanism For Recommendations, Pierpaolo Dondio, Luca Longo, Stephen Barrett

Conference papers

An important class of distributed Trust-based solutions is based on the information sharing. A basic requirement of such systems is the ability of participating agents to effectively communicate, receiving and sending messages that can be interpreted correctly. Unfortunately, in open systems it is not possible to postulate a common agreement about the representation of a rating, its semantic meaning and cognitive and computational mechanisms behind a trust-rating formation. Social scientists agree to consider unqualified trust values not transferable, but a more pragmatic approach would conclude that qualified trust judgments are worth being transferred as far as decisions taken considering others’ …

Anti-Phishing Models: Main Challenges, Edina Hatunic-Webster

Conference papers

Phishing is a form of online identity theft in which the attacker attempts to fraudulently retrieve a legitimate user's account information, logon credentials or identity information in general. The compromised information is then used for withdrawing money online, taking out cash advances, or making purchases of goods and services on the accounts. Various solutions have been proposed and developed in response to phishing. As phishing is a business problem, the solutions target both non-technical and technical areas. This paper investigates the current anti-phishing solutions and critically reviews their usage, security weaknesses and their effectiveness. The analysis of these models points …

Optimising Design Parameters Of Enzyme-Channelling Biosensors, Dana Mackey, Tony Killard

Conference Papers

Two mathematical models for an electrochemical biosensor are proposed and compared with a view to determining the ratio of two immobilized enzymes which maximizes the amperometric signal amplitude.

Object Detection And Classification With Applications To Skin Cancer Screening, Jonathan Blackledge, Dmitryi Dubovitskiy

Articles

This paper discusses a new approach to the processes of object detection, recognition and classification in a digital image. The classification method is based on the application of a set of features which include fractal parameters such as the Lacunarity and Fractal Dimension. Thus, the approach used, incorporates the characterisation of an object in terms of its texture.

The principal issues associated with object recognition are presented which includes two novel fast segmentation algorithms for which C++ code is provided. The self-learning procedure for designing a decision making engine using fuzzy logic and membership function theory is also presented and …

Nanocomposites For Novel Holographic Applications, Izabela Naydenova, Svetlana Mintova, Suzanne Martin, Vincent Toal

Articles

Nanozeolites incorporated into photopolymerizable holographic recording materials can be used for holographic sensing, data storage, and optical systems design.

Fabrication Of Switchable Liquid Crystal Devices Using Surface Relief Gratings In Photopolymer, Pavani Kotakonda, Izabela Naydenova, Robert Howard, Suzanne Martin, Vincent Toal

Articles

Holographically recorded surface relief gratings in dry, self-developing acrylamide based photopolymer were used to fabricate two types of switchable liquid crystal (LC) device. One is an electrically switchable LC diffraction grating and the other is an electrically switchable polarization rotator. The electrically switchable diffraction grating was characterized by measuring the dependence of the intensity in the first diffracted order on the applied electric field. The polarization rotator was characterized by studying the influence of the applied electric field on the twist angle and the variation of intensity in the zero and the first orders of diffraction.

Multi-Algorithmic Cryptography Using Deterministic Chaos With Applications To Mobile Communications, Jonathan Blackledge

Articles

In this extended paper, we present an overview of the principal issues associated with cryptography, providing historically significant examples for illustrative purposes as part of a short tutorial for readers that are not familiar with the subject matter. This is used to introduce the role that nonlinear dynamics and chaos play in the design of encryption engines which utilize different types of Iteration Function Systems (IFS). The design of such encryption engines requires that they conform to the principles associated with diffusion and confusion for generating ciphers that are of a maximum entropy type. For this reason, the role of …

A Visual Indication Of Environmental Humidity Using A Color Changing Hologram Recorded In A Self-Developing Photopolymer, Izabela Naydenova, Raghavendra Jallapuram, Vincent Toal, Suzanne Martin

Articles

A reflection hologram for visual indication of environmental humidity has been studied. The hologram is recorded in a self-developing photopolymer and changes color when exposed to a change in humidity and is fully reversible. The range of color change, reversibility, and the response time of the hologram have been studied in a controlled humidity environment. Fully reversible holograms with response times from few seconds to tens of minutes have been designed. Extremely sensitive bright visual humidity indicators, capable of dramatic color change within a few seconds of breathing on them are demonstrated

Method For Characterization Of Diffusion Properties Of Photopolymerisable Systems, Tzvetanka Babeva, Izabela Naydenova, Suzanne Martin, Vincent Toal

Articles

A novel approach for measuring the diffusion coefficients in photopolymerisable materials is proposed. The method is based on studying the evolution of the surface relief profile in a single illuminated spot using an interferometric surface profiler. It is shown that the observed post-exposure swelling in the illuminated spot is due to mass-transport of monomer from the unexposed to the exposed area driven by a monomer concentration gradient set up by the monomer polymerization in the exposed area. Appropriate choice of the thickness of the studied layers ensures both lateral movement of monomer and negligible contribution from the depth. The diffusion …

Technology-Aided Participative Methods In Environmental Assessment: An International Perspective, Ainhoa Gonzalez, Alan Gilmer, Ronan Foley, John Sweeney, John Fry

Articles

Provisions for citizen involvement in the assessment of potential environmental effects of certain plans, programmes and projects are present in current legislation. An international survey revealed that public participation is common practice in European and some other countries worldwide. However, a number of issues are observed to affect public involvement in EIA/SEA processes and expert opinion differs when evaluating the effectiveness of existing participative methods. Results suggest that technology-aided methods can improve traditional participation processes. In particular, GIS has the potential to increase community knowledge and enhance involvement by communicating information more effectively. Variable accessibility to technology and data quality …

Whole Field Out-Of-Plane Vibration Analysis With A Hoe-Based Espi System, Emilia Mihaylova, Viswanath Bavigadda, Raghavendra Jallapuram, Vincent Toal

Conference Papers

Electronic speckle pattern interferometry (ESPI) is a full-field measurement technique, capable of displaying vibrational mode shapes. A simple optical set-up for an ESPI system using a holographic optical element (HOE) is presented. The HOE is designed to create a speckled reference beam in the interferometer. A partially reflective glass plate provides illumination of the object along the normal to its surface, ensuring that the system is sensitive only to out-of-plane displacement of the object. It is demonstrated that the HOE-based system can be used for vibration measurements. Phase shifting can be implemented for fringe analysis. A big advantage of the …

Evaluation Of A Naive Model For Square Wave Voltammetry At A Microelectrode, Patrick Enright, John Cassidy, Tony Betts

Articles

A square wave voltammetric waveform ( SWV) was applied to an inlaid microdisk electrode in a solution of K4[Fe(CN)6]. A simple model relying on the assumption of steady state current throughout the scan was used to model the current potential behaviour. However, experimental peak current magnitudes were between 30% and 50% greater than those predicted by the model. The model predicts an increase of peak current and peak width at half height with pulse height Esw and no effect of the parameters frequency, f and step height, ΔEs. Experimental peak current magnitudes and peak current magnitudes predicted by the model …

Novel Calixarene-Schiff Bases That Bind Silver(I) Ion, Mary Deasy, Bernadette Creaven, Brian A. Murray, John Mcginley, Paul M. Flood

Articles

Two novel calix[4]arene-Schiff base receptors have been synthesized. One of the new compounds has two pendant aldimines, while the second has been prepared by two-point attachment of a calixarene-dialdehyde onto a calixarene-diamine to form a “calix-tube”. Preliminary binding studies with AgClO₄ show large complexation-induced shifts in ¹H NMR positions.

Non-Existence Of A Minimizer To The Hartree-Fock Functional, Michael Melgaard, Mattias Enstedt

Articles

In the presence of an external magnetic field, we prove absence of a ground state within the Hartree-Fock theory of atoms and molecules. The result is established for a wide class of magnetic fields when the number of electrons is greater than or equal to 2Z + K, where Z is the total charge of K nuclei. Positivity properties are instrumental in the proof of this bound for the maximal ionization

Existence Of A Solution To Hartree-Fock Equations With Decreasing Magnetic Field, Mattias Enstedt, Michael Melgaard

Articles

In the presence of an external magnetic field, we prove existence of a ground state within the Hartree–Fock theory of atoms and molecules. The ground state exists provided the magnetic field decreases at infinity and the total charge of nuclei exceeds , where is the number of electrons. In the opposite direction, no ground state exists if .