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Vibration Phase Measurements Using Holographic Optical Elements, Viswanath Bavigadda, Raghavendra Jallapuram, Vincent Toal, Emilia Mihaylova

Articles

The application of an out-of-plane sensitive electronic speckle pattern interferometer (ESPI) using holographic optical element (HOE) to vibration amplitude and phase mapping is reported. The novelty of the proposed system is the use of a speckle reference wave stored in a reflection holographic optical element (HOE). The incorporation of a HOE minimizes the alignment difficulties. The HOE based ESPI system is compact containing only a diode laser, HOE and a digital CMOS camera. The measurement technique is a combination of time averaged ESPI and reference beam phase modulation in an unbalanced interferometer. The reference beam phase modulation is implemented by …

Electronic Speckle Pattern Interferometer Using Holographic Optical Elements For Vibration Measurements, Viswanath Bavigadda, Raghavendra Jallapuram, Emilia Mihaylova, Vincent Toal

Articles

A simple and compact electronic speckle pattern interferometry (ESPI) built with holographic optical elements (HOEs) used for the study of out-of-plane vibration is reported. Carefully fabricated reflection and transmission HOEs provide reference and object beams in the interferometer. All the alignment difficulties in conventional ESPI systems are minimized using HOEs. The time average ESPI subtraction method is used to generate correlation fringes. The background speckle noise is removed by introducing a phase shift between sequential images. The amplitude and phase maps are obtained using path difference modulation in an unbalanced ESPI.

Medium Mediated Effects Increase Cell Killing In A Human Keratinocyte Cell Line Exposed To Solar Simulated Radiation, Fiona Lyng, Alanna Maguire, Brian Morrissey, James E. Walsh

Articles

Purpose: The objective of this study is to investigate whether cell culture medium is 40 a biologically relevant exposure medium that can be employed in non-ionising photobiological investigations. 42 Methods: The effect of solar simulated irradiation on cell culture medium and its ability to elicit cell death was studied. The role of reactive oxygen species (ROS), cell 44 secreted factors, and the contribution of individual components of the medium were investigated. 46 Results: Cell death was found to be primarily mediated through the formation of ROS via riboflavin photosensitisation and degradation in the cell culture medium. Phenol 48 red was …

Altered Mitochondrial Function And Genome Frequency Post Exposure To Γ-Radiation And Bystander Factors, Fiona Lyng, Sharon Nugent,, Carmel E. Mothersill,, Colin Seymour, Brendan Mcclean,, James E. J. Murphy

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PURPOSE:

To further evaluate irregular mitochondrial function and mitochondrial genome damage induced by direct γ-irradiation and bystander factors in human keratinocyte (HPV-G) epithelial cells and hamster ovarian fibroblast (CHO-K1) cells. This is as a follow-up to our recent reports of γ-irradiation-induced loss of mitochondrial function and mitochondrial DNA (mtDNA) damage.

What's In A Name?: The Role Of Danielson In The Taxation Of Credit Card Securitizations, Grace S. Lee

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No abstract provided.

Polarization Dependence Of An Edge Filter Based On Singlemode-Multimode-Singlemode Fibre, Agus Hatta, Yuliya Semenova, Ginu Rajan, Gerald Farrell

Articles

The polarization dependent loss (PDL) of a singlemode-multimodesinglemode (SMS) fibre structure used as an edge filter is presented. Minor errors in the fabrication process for the SMS fibre structure can introduce SMS fibre core offsets. The PDL due to lateral and rotational core offsets is investigated numerically and experimentally. It is shown that small core offsets are necessary to achieve low PDL for a SMS fibre based edge filter. It is also demonstrated that when lateral core offsets are unavoidable, the PDL of a SMS edge filter can still be minimized by introducing a rotational core offset of 90o.

A Study Of The Effect Of The Position Of An Edge Filter Within A Ratiometric Wavelength Measurement System, Qiang Wu, Pengfei Wang, Yuliya Semenova, Gerald Farrell

Articles

The effect of the position of an edge filter within a ratiometric wavelength measurement system was investigated based on three cases: (1) the reflected fibre Bragg grating (FBG) signal passes through both the reference arm and the edge filter arm, (2) the reflected FBG signal is connected directly to the edge filter arm and does not pass through the reference arm, (3) the edge filter sits in line with the FBG and thus the source power is filtered prior to reaching the FBG. Both numerical simulations and experimental results show that cases 1 and 2 have similar system performance whilst …

A Bend Loss Based Singlemode Fiber Micro-Displacement Sensor, Pengfei Wang, Yuliya Semenova, Qiang Wu, Gerald Farrell

Articles

An all-fiber displacement sensor with a simple configuration is proposed and investigated theoretically and experimentally. The proposed fiber displacement sensor consists of a half-loop structure of high-bend loss singlemode fiber-1060XP. A ratiometric power measurement system for interrogating the proposed sensor is also presented. By measuring the change in ratio of bend loss in the ratiometric measurement system, a change in displacement can be measured assuming the ratiometric system is calibrated. The proposed macrobending fiber based displacement sensor achieves a competitive resolution of circa 0.33 μm and also benefits from simplicity compared with the conventional fiber Bragg grating based displacement sensor. …

Dissociative Cdse/Zns Quantum Dot-Molecule Complex For Luminescent Sensing Of Metal Ions In Aqueous Solutions, A. V. Baranov, A. O. Orlova, V. G. Maslov, Yu. A. Toporova, E. V. Ushakova, A. Federov, M. V. Artemyev, T. S. Perova, Kevin Berwick

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The optical properties of dissociative luminescent sensors based on a complex consisting of highly luminescent hydrophobic core/shell CdSe/ZnS quantum dots (QDs) and 1-(2-pyridilazo)-2-naphtol (PAN) molecules in organic solutions and a polymer film are reported. It is demonstrated, using Ni²⁺ and Co²⁺ ions as an illustrative example, that the QD/PAN sensor may have applications in the quantitative luminescent sensing of metal ions in aqueous solutions.

Double Quantum Dot Photoluminescence Mediated By Incoherent Reversible Energy Transport, S. Yu Kruchinin, A. V. Federov, A. V. Baranov, T. S. Perova, Kevin Berwick

Articles

We present a theoretical study of the stationary photoluminescence of two, direct-gap, semiconductor nanocrystals, taking into account electronic excitation energy-transfer processes due to electrostatic interaction. The results obtained here allow for the incoherent reversible energy transport that occurs when the intraband relaxation rate in a quantum dot acceptor is comparable to, or less than, the energy-transfer rate. We investigate the secondary emission of two different electronic level schemes that can be realized experimentally, obtain analytical expressions for the luminescence differential cross section, and perform an analysis of its spectrum. It is shown that when excitation is not in resonance with …

Glass Frit As A Hermetic Joining Layer In Laser Based Joining Of Miniature Devices, Qiang Wu, Norbert Lorenz, Kevin Cannon, Duncan Hand

Articles

In this paper, we investigate the feasibility of using a laser as the heat source to drive a hermetic joining process based on a glass frit intermediate layer. The laser allows the necessary heat energy to be provided in a localized manner; important either as part of a multistage process, or to allow thermally-sensitive materials to be used inside the package. Our study includes an investigation of the impact of rough and grooved surfaces on the hermeticity and strength of the join, demonstrating the robust nature of the process, and its ability to allow feed-throughs to the center of package. …

Encryption Using Deterministic Chaos, Jonathan Blackledge, Nikolai Ptitsyn

Articles

The concepts of randomness, unpredictability, complexity and entropy form the basis of modern cryptography and a cryptosystem can be interpreted as the design of a key-dependent bijective transformation that is unpredictable to an observer for a given computational resource. For any cryptosystem, including a Pseudo-Random Number Generator (PRNG), encryption algorithm or a key exchange scheme, for example, a cryptanalyst has access to the time series of a dynamic system and knows the PRNG function (the algorithm that is assumed to be based on some iterative process) which is taken to be in the public domain by virtue of the Kerchhoff-Shannon …

An Optical Machine Vision System For Applications In Cytopathology, Jonathan Blackledge, Dmitry Dubovitskiy

Articles

This paper discusses a new approach to the processes of object detection, recognition and classification in a digital image focusing on problem in Cytopathology. A unique self learning procedure is presented in order to incorporate expert knowledge. The classification method is based on the application of a set of features which includes fractal parameters such as the Lacunarity and Fourier dimension. Thus, the approach includes the characterisation of an object in terms of its fractal properties and texture characteristics. The principal issues associated with object recognition are presented which include the basic model and segmentation algorithms. The self-learning procedure for …

Development Of A Panchromatic Acrylamide Based Photopolymer For Multicolour Reflection Holography, Chakrapani Meka, Raghavendra Jallapuram, Izabela Naydenova, Suzanne Martin, Vincent Toal

Articles

The development of a panchromatic acrylamide based photopolymer (ABP) for holographic recording application is presented. The scattering of the recording medium was characterised by measuring the Bidirectional Scattering Distribution Function (BSDF). The dynamic range in reflection mode of recording was evaluated by measuring the diffraction efficiencies of the holographic gratings recorded individually at 633nm, 532nm, and 473nm wavelengths at spatial frequencies of 4200 l/mm, 5000 l/mm and 5700 l/mm respectively. Spectral characterisation of the reflection gratings recorded using a combined single RGB beam was carried out and the reconstructed wavelengths were monitored and compared with the recording wavelengths. The recorded …

Space, Time And The Constitution Of Subjectivity: Comparing Elias And Foucault, Paddy Dolan

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The work of Foucault and Elias has been compared before in the social sciences and humanities, but here I argue that the main distinction between their approaches to the construction of subjectivity is the relative importance of space and time in their accounts. This is not just a matter of the “history of ideas,” as providing for the temporal dimension more fully in theories of subjectivity and the habitus allows for a greater understanding of how ways of being, acting and feeling in different spaces are related but largely unintended. Here I argue that discursive practices, governmental operations and technologies …

Of Discipline And Civilization: A Roundtable Discussion On The Legacies Of Norbert Elias And Michel Foucault, Sam Binkley, Paddy Dolan, Stefanie Ernst, Cas Wouters

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When one considers the proximity of their concerns, it is perhaps surprising that the works of Norbert Elias and Michel Foucault have not been more systematically compared and discussed. However, the differentiation of disciplinary knowledge (particularly the boundary that separates philosophy from social theory), com-pounded by parochialisms fostered by the cult of the intellectual, have delayed this process far past its due. This conversation, which began in 2008 at a conference on the works of Elias and Foucault at the University of Hamburg, is, in this regard, an effort to make up for lost time. Fashioned from hours of discussion …

The Planned And The Unplanned: A Roundtable Discussion On The Legacies Of Michel Foucault And Norbert Elias, Sam Binkley, Paddy Dolan, Stefanie Ernst, Cas Wouters

Articles

When one considers the proximity of their concerns, it is perhaps surprising that the works of Norbert Elias and Michel Foucault have not been more systematically compared and discussed. However, the differentiation of disciplinary knowledge (particularly the boundary that separates philosophy from social theory), com-pounded by parochialisms fostered by the cult of the intellectual, have delayed this process far past its due. This conversation, which began in 2008 at a conference on the works of Elias and Foucault at the University of Hamburg, is, in this regard, an effort to make up for lost time. Fashioned from hours of discussion …

Subsidiaries As Learning Engines: Understanding Middle Managers’ Searching For Knowledge As Micro-Foundation, Esther Tippmann, Pamela Sharkey Scott, Vincent Mangematin

Articles

A lot of research on MNC knowledge flows has concentrated on the organizational conditions that promote learning outcomes through a more efficient reuse of existing knowledge (cf. Gupta and Govindarajan 2000). Departing from this predominant research stream and recognising the increasingly important role of middle managers in large, distributed organizations, we investigated how subsidiary middle managers actually search for knowledge when dealing with non-routine problems and evaluated the solution outcomes in terms of generating organizational adaptation. By doing so, we contribute to several calls for more micro-level research of organizational learning processes (Felin and Foss 2005, 2009, Felin and Hesterly …

Developing Subsidiary Contribution To The Mnc-Subsidiary Entrepreneurship And Strategy Creativity, Pamela Sharkey Scott, Gibbons Patrick, Joseph Coughlan

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Despite its theoretical and managerial significance, subsidiary entrepreneurship and its effects 15 on subsidiary contribution remain underexplored in the literature.We propose that subsidiary 16 entrepreneurship encourages more creative strategic responses to escalating environmental 17 change. We explore the direct and mediating effects of subsidiary entrepreneurship on 18 subsidiary contribution to the MNC, particularly subsidiary strategy creativity. We use 19 structural equation modelling to test our propositions on data generated from surveying the 20 population of Irish subsidiaries of foreign MNCs, and find strong support for our theoretical 21 predictions. The managerial implications of subsidiary entrepreneurship in generating creative 22 strategy, …

Business Process Change In E-Government Projects: The Case Of The Irish Land Registry, Aileen Kennedy, Joseph Coughlan, Carol Kelleher

Articles

This research investigates one of the first e-Government services launched as part of Ireland’s Information Society programme, the Irish Land Registry’s implementation of their award winning Electronic Access (EAS) project. In-depth enquiries into how public sector organisations manage IT-enabled transformations have remained relatively limited and this case contributes to this emerging body of literature. The analysis highlights that the implementation of e-Government initiatives beyond basic service levels necessitates business process change in order to reap rewards. This study fulfils an identified need for research in Business Process Change (BPC) in the implementation of e-Government initiatives. In this way the research …

Simulation Algorithm And Validation Of A Photovoltaic Water Pumping System, I. Odeh, Y. Yohannis, Brian Norton

Articles

A photovoltaic (PV) water pumping system has been modelled using TRNSYS considering a power supply, a direct current (DC)/alternating current (AC) inverter, an AC induction motor, a centrifugal pump, a well, a water storage tank, and an overflow protection device. The model emulates actual pumping head curves, uses numerical methods to determine pump system working points, and includes a storage tank as a component in the system. It simulates PV-powered water pumping systems, constant voltage tracking, voltage frequency modulation, and maximum power point tracking algorithms; variable inverter frequency with variable motor efficiency, variable inverter frequency with constant motor efficiency, and …

Changes In Intraocular Pressure And Anterior Segment Morphometry After Uneventful Phacoemulsification Cataract Surgery, J. Dooley, S. Charalampidou, A. Malik, James Loughman, L. Molloy, S. Beatty

Articles

Purpose To study changes in anterior segment morphometry after uneventful phacoemulsification cataract surgery, and to investigate whether there is a relationship between any observed changes and intraocular pressure (IOP) reduction after the procedure. Methods The anterior chamber depth (ACD), anterior chamber volume (ACV), anterior chamber angle (ACA), central corneal thickness (CCT), and IOP were measured in 101 non-glaucomatous eyes before and after uneventful phacoemulsification cataract surgery. Results After cataract surgery, the mean ACD, ACV, and ACA values increased by 1.08mm, 54.4mm3, and 13.11, respectively, and the mean IOP (corrected for CCT) decreased by 3.2mmHg. The predictive value of a previously …

Macular Pigment Optical Density In An Aging Irish Population: The Irish Longitudinal Study On Ageing, John Nolan, Roseanne Kenny, Claire O'Regan, Hilary Cronin, James Loughman, Eithne Connolly, Patricia Kearney, Stephen Beatty

Articles

Purpose: The 3 carotenoids lutein, zeaxanthin, and meso-zeaxanthin, which account for the ‘yellow spot’ at the macula and which are referred to as macular pigment (MP), are believed to play a role in visual function and protect against age-related macular degeneration (AMD) via their optical and antioxidant properties. This study was undertaken to compare MP optical density (MPOD) in a population aged ≧50 years with MPOD values from a normative database of subjects aged 18–60 years. Methods: Seventy-nine subjects were recruited into this pilot study (The Irish Longitudinal Study on Ageing-TILDA). MPOD was measured using heterochromatic flicker photometry. Retinal fundus …

Macular Pigment And Its Contribution To Visual Performance And Experience [El Pigmento Macular Y Su Contribución Al Rendimiento Y Experiencia Visuals], James Loughman, Peter Davison, John M. Nolan, Mukunda C. Akkali, Stephen Beatty

Articles

There is now a consensus, based on histological, biochemical and spectral absorption data, that the yellow colour observed at the macula lutea is a consequence of the selective accumulation of dietary xanthophylls in the central retina of the living eye. Scientific research continues to explore the function(s) of MP in the human retina, with two main hypotheses premised on its putative capacity to (1) protect the retina from (photo)-oxidative damage by means of its optical filtration and/or antioxidant properties, the so-called protective hypothesis and (2) influence the quality of visual performance by means of selective short wavelength light absorption prior …

An Investigation Of The Rwpe Prostate Derived Family Of Cell Lines Using Ftir Spectroscopy, M. Baker, Colin Clarke, D. Demoulin, J. Nicolson, Fiona Lyng, Hugh Byrne, C. Hart, M. Brown, N. Clarke, P. Gardner

Articles

Interest in developing robust, quicker and easier diagnostic tests for cancer has lead to an increased use of Fourier transform infrared (FTIR) spectroscopy to meet that need. In this study we present the use of different experimental modes of infrared spectroscopy to investigate the RWPE human prostate epithelial cell line family which are derived from the same source but differ in their mode of transformation and their mode of invasive phenotype. Importantly, analysis of the infrared spectra obtained using different experimental modes of infrared spectroscopy produce similar results. The RWPE family of cell lines can be separated into groups based …

Ultrasound-Assisted Swnts Dispersion: Effects Of Sonication Parameters And Solvent Properties, Qiaohuan Cheng, Sourabhi Debnath, Elizabeth Gregan, Hugh Byrne

Articles

Ultrasonication is widely used for preparing Single-Walled Carbon Nanotube (SWNT) dispersions in different solvent media and it has been shown to play a critical role in dispersing and debundling SWNTs. The strong shear force that can exfoliate the SWNT bundles during sonication comes from cavitation, which entails a process of bubble formation, growth, and collapse. The efficiency of the cavitation process is closely correlated to many solvent parameters, including vapor pressure, viscosity, and surface tension, as well as the sonication frequency, intensity, and time. In this study, SWNTs were dispersed in a range of organic solvents assisted by tip sonication. …

A Systematic Study Of The Dispersion Of Swnts In Organic Solvents, Qiaohuan Cheng, Sourabhi Debnath, Luke O'Neill, Theresa Hedderman, Elizabeth Gregan, Hugh Byrne

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Dispersions of as-produced HiPco single-walled carbon nanotubes (SWNTs) in a series of organic solvents were prepared by dilution with the aid of tip sonication. Mild centrifugation (~ 945 g) was carried out to remove large bundles. Atomic force microscopy (AFM) studies revealed that the bundle size decreased as the dispersion was diluted. By measuring the UV-vis-NIR absorption before and after centrifugation as a function of the concentration, the dispersion limit of SWNTs in each solvent can be determined. Correlations between the dispersion limit and solvent solubility parameters, including the Hildebrand solubility parameter and three dimensional Hansen solubility parameters, are explored, …

Electrochemical Characterisation Of Poly Arylene Vinylenes, Jonathan Moghal, Patrick Lynch, Mary Mcnamara, Hugh Byrne, Gordon Chambers

Articles

The electrochemical properties of a newly synthesised set of PPV derivatives were measured by cyclic voltammetry. A new octyloxy substituted PPV derivative was first synthesised (POPV). The structure of the POPV is varied systematically by the replacement of the phenyl units by naphthyl and anthryl units and the effect of these variations on the electrochemical properties is explored. The HOMO–LOMO levels of the polymers were determined from the onset potentials for the p-doping and n-doping scans. From this the electrochemical bandgap for each of the polymers was calculated. The systematic change in the structure of the POPV results in a …

Quantitative Modelling Approaches For Ascorbic Acid Degradation And Non-Enzymatic Browning Of Orange Juice During Ultrasound Processing, Vasilis Valdramidis, Patrick J. Cullen, Brijesh Tiwari, Colm O’Donnell

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The objective of this study was to develop a deterministic modelling approach for non-enzymatic browning (NEB) and ascorbic acid (AA) degradation in orange juice during ultrasound processing. Freshly squeezed orange juice was sonicated using a 1,500 W ultrasonic processor at a constant frequency of 20 kHz and processing variables of amplitude level (24.4 – 61.0 μm), temperature (5 – 30 oC) and time (0 – 10 min). The rate constants of the NEB and AA were estimated by a primary model (zero and first order) while their relationship with respect to the processing factors was tested for a number of …

Pk/Pd Modelling Of Comb-Shaped Pegylated Salmon Calcitonin Conjugates Of Differing Molecular Weights, Sinead Ryan, Jesus Maria Frias, David H. Haddleton, David J. Brayden

Articles

Salmon calcitonin (sCT) was conjugated via cysteine-1 to novel combed-shaped end-functionalised poly(PEG) methyl ether methacrylate) (sCT-P) comb-shaped polymers, to yield conjugates of total molecular weights (MW) inclusive of sCT: 6.5, 9.5, 23 and 40 kDa. The conjugates were characterised by HPLC and their in vitro and in vivo bioactivity was measured by cAMP assay on human T47D cells and following intravenous (i.v.) injection to rats, respectively. Stability against endopeptidases, rat serum and liver homogenates was assessed. There were linear and exponential relationships between conjugate MW with potency and efficacy respectively, however the largest MW conjugate still retained 70% of E …