Digital Commons Network^™

A Photonic Crystal Fiber Based Polarimetric Sensor For Cure Monitoring Of Magneto-Rheological Smart Composite Material, Manjusha Ramakrishnan, Ginu Rajan, Yuliya Semenova, Y. Zhou, Stephen Jerrams, Gerald Farrell

Articles

A buffer stripped high birefringent photonic crystal fibre based polarimetric sensor is developed for monitoring the curing process of magnetorheological elastomer (MRE) smart composite material. Using the developed sensor, different phases of the MRE curing process are clearly visible from the phase shift variation of the embedded polarisation maintaining photonic crystal fibre (PM-PCF) sensor. During the curing process, the buffer stripped PM-PCF exhibits a stress/strain induced phase shift variation from 0 to 1.98 rad. This is a significantly large phase change, which can be used to very clearly identify the different stages in the curing process. For comparison, a fibre …

On Commutator Socle-Regular Abelian P-Groups, Brendan Goldsmith, Peter Danchev

Articles

We define the notion of a commutator socle-regular Abelian p-group. After establishing some crucial properties of commutator socle-regularity, we investigate its relationship with socle-regularity, strong socle-regularity and projection socle-regularity.

Energy And Cost Saving Of A Photovoltaic-Phase Change Materials (Pv-Pcm) System Through Temperature Regulation And Performance Enhancement Of Photovoltaics, Ahmad Hasan, Sarah Mccormack, Ming Jun Huang

Articles

The current research seeks to maintain high photovoltaic (PV) efficiency and increased operating PV life by maintaining them at a lower temperature. Solid-liquid phase change materials (PCM) are integrated into PV panels to absorb excess heat by latent heat absorption mechanism and regulate PV temperature. Electrical and thermal energy efficiency analysis of PV-PCM systems is conducted to evaluate their effectiveness in two different climates. Finally costs incurred due to inclusion of PCM into PV system and the resulting benefits are discussed in this paper. The results show that such systems are financially viable in higher temperature and higher solar radiation …

Opt-Out Education: School Choice As Racial Subordination, Osamudia R. James

Articles

Despite failure to improve academic outcomes or close the achievement gap, school-choice policies, advanced by education legislation and doctrine, have come to dominate public discourse on public education reform in the United States, with students of color disproportionately enrolling in voucher programs and charter schools. This Article moves past the typical market-based critiques of school choice to analyze the particularly racialized constraints on choice for marginalized students and their families in the public school system. The Article unpacks the blame-placing that occurs when the individualism and independence that school choice and choice rhetoric promote fail to improve academic outcomes, and …

Self-Regulated Learning And The Role Of Eportfolios In Business Studies, Amparo Soler-Dominguez, Lucia Morales, Valentina Tarkovska

Articles

Through a case study supported by observation techniques, and questionnaires to gather data, we explored the use of ePortfolios as an efficient assessment tool to assist business degree students. Our main focus was a postgraduate course in which finance modules were a major component. We analysed the role of ePortfolios in Higher Education Institutions over a period of four academic years. Our findings suggest that ePortfolios could be used to facilitate and enhance students’ selfregulated learning. The role of the instructor was found to be fundamental in the early stages of the learning process. This role diminished as students became …

A Linearised Singularly Perturbed Convection-Diffusion Problem With An Interior Layer, Eugene O'Riordan, Jason Quinn

Articles

A linear time dependent singularly perturbed convection-diffusion problem is examined. The convective coefficient contains an interior layer (with a hyperbolic tangent profile), which in turn induces an interior layer in the solution. A numerical method consisting of a monotone finite difference operator and a piecewise-uniform Shishkin mesh is constructed and analysed. Neglecting logarithmic factors, first order parameter uniform convergence is established.

Delayed Rejection Algorithm To Estimate Bayesian Social Networks, Alberto Caimo, Antonietta Mira

Articles

Statistical social network analysis has become a very active and fertile area of research in the recent past. Recent developments in Bayesian computational methods have been successfully applied to estimate social network models. The Delayed rejection (DR) strategy is a modification of the Metropolis-Hastings (MH) algorithms that reduces the variance of the resulting Markov chain Monte Carlo estimators and allows partial adaptation of the proposal distribution. In this paper we show how the DR strategy can be exploited to estimate dyadic independence social network models leading to an average 40% variance reduction relative to the competing MH algorithm, confirming that …

H-Index For Quantifying The Fractal Or Scaling Structure Of Geographic Features, Bin Jiang, Junjun Yin

Articles

Although geographic features, such as mountains and coastlines, are fractal, some studies have claimed that the fractal property is not universal. This claim, which is dubious, is mainly attributed to the strict definition of fractal dimension as a measure or index for characterizing the complexity of fractals. In this article, we propose an alternative, ht-index, to quantify the fractal or scaling structure of geographic features. A geographic feature has ht-index (h) if the pattern of far more small things than large ones recurs (h – 1) times at different scales. The higher the ht-index, the more complex …

Experimental Study And Analysis Of A Polymer Fiber Bragg Grating Embedded In A Composite Material, Ginu Rajan, Manjusha Ramakrishnan, Yuliya Semenova, Eliathamby Ambikairajah, Gerald Farrell, Gang-Ding Peng

Articles

The characteristics of polymer fiber Bragg gratings (FBGs) embedded in composite materials are studied in this paper and are compared with characteristics of their silica counterparts. A polymer FBG of 10 mm length which exhibits a peak reflected wavelength circa 1530 nm is fabricated and characterized for this purpose. A silica FBG with a peak reflected wavelength circa 1553 nm is also embedded in the composite material for a comparison study. The fabricated composite material sample with embedded sensors is subjected to temperature and strain changes and the corresponding effects on the embedded polymer and silica FBGs are studied. The …

A Numerical Method For A Nonlinear Singularly Perturbed Interior Layer Problem Using An Approximate Layer Location, Jason Quinn

Articles

A class of nonlinear singularly perturbed interior layer problems is examined in this paper. Solutions exhibit an interior layer at an a priori unknown location. A numerical method is presented that uses a piecewise uniform mesh refined around approximations to the first two terms of the asymptotic expansion of the interior layer location. The first term in the expansion is used exactly in the construction of the approximation which restricts the range of problem data considered. The method is shown to converge point-wise to the true solution with a first order convergence rate (overlooking a logarithmic factor) for sufficiently small …

Bergm: Bayesian Exponential Random Graphs In R, Alberto Caimo, Nial Friel

Articles

In this paper we describe the main featuress of the Bergm package for the open-source R software which provides a comprehensive framework for Bayesian analysis for exponential random graph models: tools for parameter estimation, model selection and goodness-of-fit diagnostics. We illustrate the capabilities of this package describing the algorithms through a tutorial analysis of three network datasets.

New Insights On Free Energies And Saint-Venant’S Principle In Viscoelasticity, L. Diseri, G. Gentili, John Murrough Golden

Articles

This work was conceived in 1999 and brought near completion by 2003. Giorgio Gentili was deeply involved in this research until his untimely death. He is greatly missed. Work pressures on the other authors forced a postponement of research on this topic, originally envisaged as lasting a few months but in the event it turned out to be nearly ten years. We now dedicate this work to the memory of Giorgio and to his Family.

Access To Optometric Education: Challenges In Sub-Saharan Africa, James Loughman, V.R. Moodley, Brien Holden, K. Naidoo

Articles

Access to education was identified as a key international priority by UNESCO as far back as 1998 when it called for “equality of access”. The profession of optometry has been challenged to educate practitioners in increasing numbers in order to meet the eye care needs. The World Health Organization reported that globally, an estimated 285 million people are visually impaired and in Sub Saharan Africa (SSA) uncorrected refractive error is the main cause of visual impairment. The number of optometrists trained on the continent is currently insufficient to meet these eye care needs with limited access to education remaining a …

Ultrasound Assisted Hydration Of Navy Beans (Phaseolus Vulgaris), N. Misra

Articles

The use of ultrasound to enhance the transport phenomena in food processes has been well recognised in recent times. The objective of this study was to evaluate the effect of sonication on hydration rate and pasting profile of navy beans. The hydration kinetics for control and ultrasound assisted soaking was mathematically described using mechanistic (Fickian diffusion) and empirical (Peleg’s equation, Weibull model and First Order equation) models. Ultrasound enhanced the rate of hydration which was evident from the plot of kinetic data and model parameters. The effective diffusivities for water transport without and with ultrasound application were estimated to be …

Towards A Computational Analysis Of Probabilistic Argumentation Frameworks, Pierpaolo Dondio

Articles

In this paper we analyze probabilistic argumentation frameworks (PAFs), defined as an extension of Dung abstract argumentation frameworks in which each argument n is asserted with a probability p(n). The debate around PAFs has so far centered on their theoretical definition and basic properties. This work contributes to their computational analysis by proposing a first recursive algorithm to compute the probability of acceptance of each argument under grounded and preferred semantics, and by studying the behavior of PAFs with respect to reinstatement, cycles and changes in argument structure. The computational tools proposed may provide strategic information for agents selecting the …

Hamiltonian Approach To The Modeling Of Internal Geophysical Waves With Vorticity, Alan Compelli

Articles

We examine a simplified model of internal geophysical waves in a rotational 2-dimensional water-wave system, under the influence of Coriolis forces and with gravitationally induced waves. The system consists of a lower medium, bound underneath by an impermeable flat bed, and an upper lid. The 2 media have a free common interface. Both media have constant density and constant (non-zero) vorticity. By examining the governing equations of the system we calculate the Hamiltonian of the system in terms of its conjugate variables and perform a variable transformation to show that it has canonical Hamiltonian structure. We then linearize the system, …

Symmetry And Reductions Of Integrable Dynamical Systems: Peakon And The Toda Chain Systems, Vladimir Gerdjikov, Rossen Ivanov, Gaetano Vilasi

Articles

We are analyzing several types of dynamical systems which are both integrable and important for physical applications. The first type are the so-called peakon systems that appear in the singular solutions of the Camassa-Holm equation describing special types of water waves. The second type are Toda chain systems, that describe molecule interactions. Their complexifications model soliton interactions in the adiabatic approximation. We analyze the algebraic aspects of the Toda chains and describe their real Hamiltonian forms.

Complex Absorbing Potential Method For Dirac Operators. Clusters Of Resonances, Jimmy Kungsman, Michael Melgaard

Articles

For both nonrelativistic and relativistic Hamiltonians, the Complex Absorbing Potential (CAP) method has been applied extensively to calculate resonances in Physics and Chemistry. We study clusters of resonances for the perturbed Dirac operator near the real axis and, in the semiclassical limit, we establish the CAP method rigorously by showing that resonances are perturbed eigenvalues of the nonselfadjoint CAP Hamiltonian, and vice versa.

Evaporation Screening, Scattering, And Quantum Tunneling Near The Horizons Of Schwarzschild And Reissner-Nordstroem Black Holes, Emil Prodanov

Articles

For the radial motion of massive particles with large angular momenta in Schwarzschild geometry and that of massive charged particles with large
angular momenta or energy in a particular range in Reissner-Nordstroem geometry, there exist classically forbidden regions on the outside of
the respective event horizons which scatter certain in-falling geodesics or screen some of the black holes' evaporation by reflecting the emitted

particles back into the black holes. Quantum tunneling across this forbidden regions is studied.

Hamiltonian Formulation Of 2 Bounded Immiscible Media With Constant Non-Zero Vorticities And A Common Interface, Alan Compelli

Articles

We examine a 2-dimensional water-wave system, with gravitationally induced waves, consisting of a lower medium bound underneath by an impermeable flat bed and an upper medium bound above by an impermeable lid such that the 2 media have a free common interface. Both media have constant density and constant (non-zero) vorticity. By examining the governing equations of the system we calculate the Hamiltonian of the system in terms of it's conjugate variables and per- form a variable transformation to show that it has canonical Hamiltonian structure.

Using Structure-Based Organic Chemistry Online Tutorials With 2 Automated Correction For Student Practice And Review, Timothy O'Sullivan, Gráinne Hargaden

Articles

This article describes the development and implementation of an open-access organic chemistry question bank for online tutorials and assessments at University College Cork and Technological University Dublin. SOCOT (structure-based organic chemistry online tutorials) may be used to supplement traditional small-group tutorials, thereby allowing students to develop essential problem-solving skills in organic chemistry. This online approach may be used for both formative and summative assessment. Students complete one problem set weekly or fortnightly, which consists of a number of questions of varying difficulty. A wide range of question types is possible; for example, prediction of reaction products, identification of reaction intermediates …

In Vitro Oxygen Availability Modulates The Effect Of Artesunate On Hela Cells, James Murray, Sandra Gannan, Sarah Rawe, James Murphy

Articles

Background/Aim: Hypoxia can affect chemo - therapeutic drug efficacy in cancer patients, yet related in vitro assays in oxygen-rich environment remain the norm. Such levels are well beyond normoxic/hypoxic levels typically experienced by normal tissues/tumor masses. The present study evaluated how artesunate anti-tumor efficacy is modulated by oxygen availability in HeLa cells and its implications for future in vitro analyses. Materials and Methods: Real-time cell analysis was employed to evaluate HeLa cell toxicity to artesunate at 21%, 4% or 1% oxygen. Cell count analysis was performed to validate real-time data. Results: An increase in artesunate efficacy was observed when oxygen …

Vibrational Spectroscopic Analysis Of Body Fluids: Avoiding Molecular Contamination Using Centrifugal Filtration, Franck Bonnier, Matthew Baker, Hugh Byrne

Articles

The use of centrifugal filtration for protein purification and concentration represents an important improvement for the application of vibrational spectroscopy to analysis of bodily fluids based on protein fractions with specific molecular weight. Vibrational spectroscopic techniques are highly specific and can potentially detect small variations in the protein content indicating the presence of different diseases, therefore usable as markers for early diagnostic. However, due to the high sensitivity of the techniques, it is essential to verify that no molecular contamination occurs during the preparation of the samples. Concentration of the blood serum using commercially available centrifugal filters has been shown …

Antibody-Drug Gold Nanoantennas With Raman Spectroscopic Fingerprints For In Vivo Tumour Theranostics, Joao Conde, Chenchen Bao, Daxiang Cui, Pedro Baptista, Furong Tian

Articles

Inspired by the ability of SERS nanoantennas to provide an integrated platform to enhance disease targeting in vivo, we developed a highly sensitive probe for in vivo tumoral recognition with the capacity to target specific cancer biomarkers such as epidermal growth factor receptors (EGFR) on human cancer cells and xenograft tumour models. Here, we used ~90 nm gold nanoparticles capped by a Raman reporter, encapsulated and entrapped by larger polymers and a FDA antibody-drug conjugate –Cetuximab (Erbitux®) – that specifically targets EGFR and turns off a main signalling cascade for cancer cells to proliferate and survive. These drug/SERS gold nanoantennas …

Graduate Teaching Assistants; Critical Colleagues Or Casual Components In The Undergraduate Learning Laboratory? An Exploration Of The Role Of The Postgraduate Teacher In The Sciences., Barry Ryan

Articles

Laboratory training is key to many science subjects and those that teach the practical laboratory skills maintain a pivotal role in undergraduate science training. Graduate Teaching Assistants (GTAs) are regularly used in higher education institutes to teach these practical lab skills. The GTA can be involved in both laboratory teaching and assessing all levels of undergraduates. This varied and challenging role requires support from the institute and if appropriately provided the learning experience can be rewarding not only for the undergraduate, but also for the GTA. In this review, the critical role of the laboratory GTA will be examined, their …

The Long-Term Tort: In Search Of A New Causation Framework For Natural Resources Damages, Sanne H. Knudsen

Articles

Recent scientific evidence is proving that toxic releases have long-term, unintended, and harmful consequences for the marine environment. Though a new paradigm is emerging in the scientific literature--one demonstrating that long-term impacts from oil spills are more significant than previously thought--legal scholars, regulators, and courts have yet to consider the law's ability to remedy long-term ecological harms.

While scholars have exhaustively debated causation questions related to latent injuries for toxic torts, they have overlooked the equally important and conceptually similar causation problems of long-term damages in the natural resource context. Likewise, only a few courts have considered the standards of …

Size Dependent Translocation And Fetal Accumulation Of Gold Nanoparticles From Maternal Blood In The Rat, Manuela Semmler-Behnke, Jens Lipka, Alexander Wenk, Martin Schaeffer, Furong Tian, Gunter Schmid, Gunter Oberdorster, Wolfgang Kreyling

Articles

There is evidence that nanoparticles (NP) cross epithelial and endothelial body barriers. We hypothesized that gold (Au) NP, once in the blood circulation of pregnant rats, will cross the placental barrier during pregnancy size-dependently and accumulate in the fetal organism by 1. transcellular transport across the hemochorial placenta, 2. transcellular transport across amniotic membranes 3. transport through ~20 nm wide transtrophoblastic channels in a size dependent manner. The three AuNP sizes used to test this hypothesis are either well below, or of similar size or well above the diameters of the transtrophoblastic channels.

Electrodeposition And Characterisation Of Copolymers Based On Pyrrole And 3,4-Ethylenedioxythiophene In Bmim Bf4 Using A Microcell Configuration, Lavinia Astratine, Edmond Magner, John Cassidy, Tony Betts

Articles

Electrochemical copolymerization of pyrrole (Py) and 3,4-ethylenedioxythiophene (EDOT) was performed in an ionic liquid 1-butyl-3-methylimidazolium tetrafluoroborate, (BMIM BF4) employing a ‘micro-cell’ in order to use the materials efficiently. Characterization of the copolymers formed on an ITO substrate was performed for different Py: EDOT ratios (1:2, 1:1, 2:1) in both aqueous and ionic liquid electrolytes. Electrochemical and spectroelectrochemical analysis revealed that the properties of the copolymer depend upon the Py/EDOT monomer ratio used. The copolymer PPy-co-PEDOT (2:1) displayed good stability, a switching time of 20 s and a colouration efficiency of 101.3 C-1cm2. The presence of Py in the copolymer stabilised …

Matrix G-Strands, Darryl Holm, Rossen Ivanov

Articles

We discuss three examples in which one may extend integrable Euler–Poincare ordinary differential equations to integrable Euler–Poincare partial differential
equations in the matrix G-Strand context. After describing matrix G-Strand examples for SO(3) and SO(4) we turn our attention to SE(3) where the matrix G-Strand equations recover the exact rod theory in the convective representation. We then find a zero curvature representation of these equations and establish the conditions under which they are completely integrable. Thus, the G-Strand equations turn out to be a rich source of integrable systems. The treatment is meant to be expository and most concepts are explained …

Progress In Zeolite Synthesis Promotes Advanced Applications, Moussa Zaarour, Biao Dong, Izabela Naydenova, Richard Retoux, Svetlana Mintova

Articles

This article outlines the importance of zeolite synthesis and their unique physicochemical characteristics promoting advanced applications. The main strategies for preparation of zeolites including organic-template assisted, organic-template free and alternative procedures are considered for synthesis of crystallites offering control and fine-tuning of their properties. Besides, rational design of zeolites with pre-determined structure, porosity, size, morphology, and composition are more viable by studying carefully the chemical and physical parameters controlling the zeolite synthesis and understanding the crystallization mechanism. Finally, a particular attention to the preparation of zeolites with nanosized dimensions and their utilization in innovative applications including photovoltaic, medicine and holographic …