Engineering Commons^™

Holographically Recorded Photopolymer Diffractive Optical Element For Holographic And Electronic Speckle Pattern Interferometry, Sridhar Guntaka, Vincent Toal, Suzanne Martin

Articles

A diffractive optical element is described that can be used to implement a self-aligning electronic speckle apttern interferometer and holographic interferometer requiring only a laser source and a camera in the optical set-up.

Precise Chemical Analysis Development For Si And Gaas Surfaces, T. A. Briantseva, Z. M. Lebedeva, D. V. Lioubtchenko, M. Nolan, T. S. Perova, R. A. Moore, Kevin Berwick

Articles

Precise chemical analysis (PCA) was developed to allow the study of non-interconnected atoms on crystalline semiconductor surfaces, such as those produced during rapid thermal processing (RTP) of silicon and electron beam lithography on gallium arsenide (GaAs). The PCA method is based on selectively dissolving the different components present on the semiconductor surface using preferential etchant solutions. After etching, the etchant solution, containing the etched component, is analyzed by a photometric technique. In this paper, we present photometric measurements of the amount of “free” (non-interconnected) atoms that remain on semiconductor surfaces following electron beam and RTP processing. In this context, “free” …

Calculation For The Parameter "Deflection" In A New Theory Of The Earth's Magnetic Field, Annraoi De Paor, Ted Burke

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In a recent paper on the theory of the Earth’s magnetic field and key features of Sunspot activity (de Paor, 2001), a central role in the calculation of secular variations of the geomagnetic field was played by a newly-introduced parameter called the deflection (abbreviated def ). In this note, the significance of def is elucidated and the method used to calculate it is explained

Ancient Astronomical Alignments: Fact Or Fiction?, Frank Prendergast

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No abstract provided.

Flow Patterns In A Two-Roll Mill, Christopher Hills

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The two-dimensional flow of a Newtonian fluid in a rectangular box that contains two disjoint, independently-rotating, circular boundaries is studied. The flow field for this two-roll mill is determined numerically using a finite-difference scheme over a Cartesian grid with variable horizontal and vertical spacing to accommodate satisfactorily the circular boundaries. To make the streamfunction numerically determinate we insist that the pressure field is everywhere single-valued. The physical character, streamline topology and transitions of the flow are discussed for a range of geometries, rotation rates and Reynolds numbers in the underlying seven-parameter space. An account of a preliminary experimental study of …

Application Of Digital Image Processing To Marker-Free Analysis Of Human Gait, Jane Courtney, David Burke, Annraoi Depaor

Articles

The standard method of human gait analysis in use in gait laboratories today invariably involves marker-based motion tracking systems. Although somewhat effective, these methods require accurate placement of awkward external markers. We report on an enhanced approach being researched and developed at the National Rehabilitation Hospital, Dublin based on marker-free motion tracking incorporating advanced digital image processing techniques.

Sharing Health-Care Records Over The Internet, Jane Grimson, Gaye Stephens, Benjamin Jung, William Grimson, Damon Berry, Sebastien Pardon

Articles

Presents a novel approach to sharing electronic health-care records that leverages the Internet and the World Wide Web, developed as part of two European Commission-funded projects, Synapses and SynEx. The approach provides an integrated view of patient data from heterogeneous, distributed information systems and presents it to users electronically. Synapses and SynEx illustrate a generic approach in applying Internet technologies for viewing shared records, integrated with existing health computing environments. Prototypes have been validated in a variety of clinical domains and health-care settings

Preparation Of Magnetic Nanoparticles And Their Assemblies Using A New Fe(Ii) Alkoxide Precursor, Suresh Pillai, Grainne Biddlecombe, Yurii Gun’Ko, John Kelly, J. Michael Coey, Alexis Douvalis

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No abstract provided.

Magnetic Nanoparticles And Nanoparticle Assemblies From Metallorganic Precursors, Suresh Pillai, Yurri Gunko, David Mcinerney

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No abstract provided.

The Problem Of A Viscoelastic Cylinder Rolling On A Rigid Half-Space, John Murrough Golden, G.A.C. Graham

Articles

The problem of a viscoelastic cylinder rolling on a rigid base, propelled by a line force acting at its centre, is solved in the noninertial approximation. The method used is based on a decomposition of hereditary integrals developed by the authors in previous work, and on the viscoelastic Kolosov-Muskhelishvili equations which are used to generate a Hilbert problem. In this formulation, the problem reduces to a nonsingular integral equation in space and time, which simplifies under steady-state conditions and for exponential decay materials, to algebraic form. There are also two subsidiary conditions.

In the case of a standard linear model, …

Eddy Structures Induced Within A Wedge By A Honing Circular Arc, C. P. Hills

Articles

In this paper we outline an expeditious numerical procedure to calculate the Stokes flow in a corner due to the rotation of a scraping circular boundary. The method is also applicable to other wedge geometries. We employ a collocation technique utilising a basis of eddy (similarity) functions introduced by Moffatt (1964) that allows us to satisfy automatically the governing equations for the streamfunction and all the boundary conditions on the surface of the wedge. The circular honing problem thereby becomes one-dimensional requiring only the satisfaction of conditions on the circular boundary. The advantage of using the Moffatt eddy functions as …

Eddies Induced In Cylindrical Containers By A Rotating End Wall, Christopher Hills

Articles

The flow generated in a viscous liquid contained in a cylindrical geometry by a rotating end wall is considered. Recent numerical and experimental work has established several distinct phases of the motion when fluid inertia plays a significant role. The current paper, however, establishes the nature of the flow in the thus far neglected low Reynolds number regime. Explicitly, by employing biorthogonality relations appropriate to the current geometry, it is shown that a sequence of exponentially decaying eddies extends outward from the rotating end wall. The cellular structure is a manifestation of the dominance of complex eigensolutions to the homogeneous …

Improved Direct Solver For Building Energy Simulation, Michael Crowley, Saleem Hashmi

Articles

Finite difference methods, when applied to the differential equations modelling energy flows in buildings, give rise to a system of non-linear difference equations. A frequently used direct solution method involving linearization is analysed and a related method proposed. These and one other connected method are compared using a building related test problem prepared for this purpose. The proposed numerical method is found to produce least error, about 30% less than the commonly used method, and it is recommended for inclusion in building energy simulation software. A fundamental method for estimating the pre conditioning period of a building, arising from the …

Micro-Raman Study Of Stress Distribution Generated In Silicon During Proximity Rapid Thermal Diffusion, M. Nolan, T. Perova, R. A. Moore, C. J. Moore, Kevin Berwick, H. S. Gamble

Articles

proximity rapid thermal diffusion (RTD). A compressive stress was found on the whole silicon wafer after 15 s RTD. After 165 s RTD, the distribution of the stress across the wafer was found to be different: compressive at the edge and tensile at the middle. Thermal stress was relieved in the RTD wafers via slip dislocations. These slip dislocations were observed in the product wafers using optical microscopy. Slip lines propagated from the wafer edge to the wafer centre in eight preferred positions of maximum induced stress. The thermally induced stress and the slip dislocation density increased with time spent …

Rotary Honing: A Variant Of The Taylor Paint-Scraper Problem, Christopher Hills, H. Moffatt

Articles

The three-dimensional Row in a corner of fixed angle α induced by the rotation in its plane of one of the boundaries is considered. A local similarity solution valid in a neighbourhood of the centre of rotation is obtained and the streamlines are shown to be closed curves. The effects of inertia are considered and are shown to be significant in a small neighbourhood of the plane of symmetry of the flow. A simple experiment confirms that the streamlines are indeed nearly closed; their projections on planes normal to the line of intersection of the boundaries are precisely the 'Taylor' …

Synthesis Of Thermally Stable, High Surface Area Anatase–Alumina Mixed Oxides, Suresh Pillai, Hareesh Us, Rajeshkumar S, Mukundan P, Kgk Warrier

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No abstract provided.

The Appearance Of Ferrielectric Phases In Confined Liquid Crystal Studied By Photon Correlation Spectroscopy, Yuri Panarin, Fouad M. Aliev, Charles Rosenblatt

Articles

The influence of confinement on the dynamic properties and appearance of ferrielectric phases has been investigated by dynamic light scattering, performed in the bulk AFLC as well as confined in 200 8, and 2000 8, cylindrical pores. The analysis of the experimental results shows that the ferrielectric phases are not formed in 200 A pores, while they appear in 2000 8, pores as well as in bulk.

Investigation Of The Thickness Mode In Surface Stabilized Ferroelectric Liquid Crystal Cells, O.E. Kalinovskaya, J.K. Vij, Yu. V. Tretyakov, Yuri Panarin, Yu. P. Kalmykov

Articles

Dielectric properties of surface stabilized ferroelectric liquid crystal (SSFLC) cells have been investigated both experimentally and theoretically. The thickness mode is found to consist of two relaxation processes. A decomposition of an analytical solution of the complex dielectric permittivitye(v) in terms ofthese processesis given. Theexperimental results showagreement with theory and lead to the conclusion that the thickness mode can be separated into two processes. It has been found that the ratio of the dielectric strengths for the two processes depends on the cell thickness, and that the ratio of their frequencies is approximately equal to 10. The lower frequency process …

The Dynamic Properties Of Confined Antiferroelectric Liquid Crystal Investigated By Photon Correlation Spectroscopy, Yuri Panarin, C. Rosenblatr, F.M. Aliev

Articles

Dynamic light scattering was used to examine ferrielectric liquid crystalline phases in porous media. Whereas in larger pores (200 Å) ferrielectric phases were observed, they were not found in the smallest pores (200 Å). Additionally, the temperatures of SmC - SmA phase transition were found to be suppressed in the pores relative to bulk, while SmCA - SmCγ phase transition is not affected by the confinement. These observations have been explained by the structural aspects of antiferroelectric liquid crystalline materials in a confined geometry and show the importance of long range electrostatic interaction for existence of ferrielectric phases.

The Dynamic Properties Of 5cb Filled With Aerosil Particles Investigated By Pcs, F.M. Aliev, M. Kreuzer, Yuri Panarin

Articles

Nematic liquid crystal filled with Aerosil particles, a prospective composite material for optoelectronic application, has been investigated by static light scattering and Photon Correlation Spectroscopy (PCS). The Aerosil particles in filled nematic liquid crystals (FN) form a network structure with LC domains about 2500 Å in size with a random distribution of the director orientation of each domain. We found that the properties of 5CB are considerably affected by the network. The N-I phase transition in filled 5CB was found to be smeared out and depressed. PCS experiments show that two new relaxation processes appear in filled 5CB in addition …

Evaluation Of Implicit Numerical Methods For Building Energy Simulation, Michael Crowley, Saleem Hashmi

Articles

The stability of numerical methods used for finite-difference thermal modelling of buildings is discussed. A known instability in a commonly used process is described and alternative numerical methods with suitable stability properties are identified. With a view to selecting the optimum numerical method, the building energy simulation problem is characterized mathematically and appropriate implicit solvers are compared on the basis of accuracy and computational effort using a building related test problem prepared for this purpose. A recently developed numerical method with the necessary strong stability is found to possess higher computational efficiency than methods frequently used in this application and …

Strategies For Evaluating Software Usability, Ronan Fitzpatrick

Articles

This paper presents a usage analysis and taxonomy of methods which are used to evaluate the usability of computer systems. To accommodate the analysis and taxonomy, a matrix of strategies which can be used for effective usability evaluation is presented. Such an analysis, taxonomy and strategies support human-computer interaction (HCI) professionals who have the responsibility for ensuring computer system usability. The strategies outlined are named Virtual Engineering, Soft Modelling, Hard Review and Real World. This paper also uses a composite set of existing popular generic evaluation methods which can be used as part of these strategies. The methods used are …

A Corba-Base Integration Of Distributed Electronic Healthcare Records Using The Synapses Approach, Jane Grimson, William Grimson, Damon Berry, Gaye Stephens, Eoghan Felton, Dipak Kalra, Pieter Toussaint, Onno Weir

Articles

The ability to exchange in a meaningful, secure, and simple fashion relevant healthcare data about patients is seen as vital in the context of efficient and cost-effective shared or team-based care. The electronic healthcare record (EHCR) lies at the heart of this information exchange, and it follows that there is an urgent need to address the ability to share EHCR's or parts of records between carers and across distributed health information systems. This paper presents the Synapses approach to sharing based on a standardized shared record, the Federated Healthcare Record, which is implemented in an open and flexible manner using …

White Light Interferometric Surface Profiler, Vincent Toal, Brian Bowe

Articles

We describe an optical system for 3-D profilometry based on the white light interferometer. We detail a simple way to construct a profiler that uses two simple algorithms which deal efficiently and quickly with the data. The system has a theoretically unlimited range and can deal with rough and smooth surfaces

The Investigation Of The Relaxation Process In Antiferroelectric Liquid Crystals By Electro-Optic Spectroscopy, Yuri Panarin, O. Kalinovskaya, J.K. Vij

Articles

Electrooptic spectroscopy of an antiferroelectric liquid crystal is carried out over a range of frequencies from 1 Hz to 100 kHz. In the antiferroelectric SmCA phase two relaxation processes are found, one at the fundamental frequency of a mode and the second at twice the frequency of a different mode. A comparison of the results of the electro-optic spectroscopy with a theoretical study of the motion of the director of an antiferroelectric helix subject to a weak alternating field enables a determination of the origin of the relaxation processes in antiferroelectric phases. © 1998 American Institute of Physics.

Observation And Investigation Of The Ferrielectric Subphase With High Qt Parameter, Yuri Panarin, O. Kalinovskaya, J.K. Vij, J.W. Goodby

Articles

Dielectric relaxation processes in an antiferroelectric liquid crystal (AFLC) have been investigated over a wide range of frequencies from 1 Hz to 1 GHz. The AFLC under investigation possesses a variety of different ferrielectric, ferroelectric, and antiferroelectric phases. Dielectric and polarization measurements under direct bias voltage have been made with a view to clarifying the origin of the high-temperature ferrielectric phase, which appears between the AF and smectic-C phases. This phase is assigned to an unstable ferrielectric phase with qT parameter greater than 1/2 (according to the Ising model) or a doubly modulated incommensurate phase (according to the expanded Landau …

The Short-Term Effects Of Mortars On Salt Movement In Stone, Simon H. Perry, Aidan Duffy

Articles

Salt-induced decay processes are one of the most important reasons for the decay of many stone buildings and monuments. This paper investigates the role played by masonry mortars in the movement of salts within Baumberger sandstone and Portland limestone. The methodology used involved the monitoring of stone units containing mortar joints which were exposed to a city-centre environment. Rain-water run-off was collected from the stone/mortar units during the exposure period; the units were subsequently destructively analysed. The methods of run-off and destructive sample analysis used included ion chromatography and atomic absorption spectrophotometry; stone and mortar samples were also analysed petrographically. …

Observation And Investigation Of The Ferrielectric Subphase With Qt>1/2, Yuri Panarin, O. Kalinovskaya, J. K. Vij

Articles

The high-temperature femelectric phase with qT > 1/2 has been found to exist in a antiferroelectric liquid crystal. This phase has been identified using dielectric spectroscopy and conoscopy.

Investigation Of The Ferrielectric Subphase With Qt>1/2 Under Bias Voltage, Yuri Panarin, O.E. Kalinovskaya, J.K. Vij

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The properties of Femelectric phase with qT > 112 have been investigated using broadband dielectric spectroscopy and polarization measurements under the bias voltage. The field -induced sequence of phase transitions is found to be different fiom those of the conventional femelectric phases with qTS 112

A Study Of Antiferroelectric Liquid Crystals Using The Pyroelectric Technique, J.W. O'Sullivan, Yuri Panarin, J.K. Vij, A.J. Seed, M. Hird, J.W. Goodby

Articles

Antiferroelectric liquid crystals are studied using the pyroelecmc technique. The effects of temperature and applied voltage on the pyroelectric signal are examined. The pyroelecmc signal can detect phase changes that occur due to temperature and bias voltage. A high temperature femelecmc phase FiLC is found and the stability of this phase under different bias voltages is examined