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Articles 1 - 30 of 40
Full-Text Articles in Engineering
Hand-Held Flyback Driven Coaxial Dielectric Barrier Discharge: Development And Characterization, Victor J. Law, Vladimir Milosavljevic, Neil O’Connor, James F. Lalor, Steven Daniels
Hand-Held Flyback Driven Coaxial Dielectric Barrier Discharge: Development And Characterization, Victor J. Law, Vladimir Milosavljevic, Neil O’Connor, James F. Lalor, Steven Daniels
Articles
The development of a handheld single and triple chamber atmospheric pressure coaxial dielectric barrier discharge driven by Flyback circuitry for helium and argon discharges is described. The Flyback uses external metal-oxide-semiconductor field-effect transistor power switching technology and the transformer operates in the continuous current mode to convert a continuous dc power of 10–33 W to generate a 1.2–1.6 kV 3.5 μs pulse. An argon discharge breakdown voltage of ∼768 V is measured. With a 50 kHz, pulse repetition rate and an argon flow rate of 0.5–10 argon slm (slm denotes standard liters per minute), the electrical power density deposited in …
Equi-Biaxial Fatigue Of Elastomers: The Effect Of Oil Swelling On Fatigue Life, Stephen Jerrams, John Hanley, Niall Murphy, Ali Hassan
Equi-Biaxial Fatigue Of Elastomers: The Effect Of Oil Swelling On Fatigue Life, Stephen Jerrams, John Hanley, Niall Murphy, Ali Hassan
Articles
The effect of oil swelling on the fatigue life of ethylene propylene diene monomer rubber (EPDM) has been studied under conditions of equi-biaxial cycling using dynamic bubble inflation. Specimens were subjected to varying degrees of swelling in reference mineral oils and fatigued at constant engineering stress amplitudes. The reference oils used for swelling the EPDM had known aniline points, allowing the rubber-oil compatibility to be determined. The inflation fluid for fatigue testing was selected with a solubility parameter that would produce a desired level of incompatibility with the test specimens, thereby limiting the amount of additional swelling during cycling. Wöhler …
Temperature Dependence Of Macrobending Loss In All-Fiber Bend Loss Edge Filter, Pengfei Wang, Yuliya Semenova, Gerald Farrell
Temperature Dependence Of Macrobending Loss In All-Fiber Bend Loss Edge Filter, Pengfei Wang, Yuliya Semenova, Gerald Farrell
Articles
A theoretical model for macrobending-induced temperature dependent loss (TDL) for a standard singlemode fiber (SMF28) with dual coating layers is presented, with good agreement demonstrated between theoretical calculations and experimental results. The impact of temperature on two examples of an all-fiber based edge filter is also investigated theoretically and experimentally and using the developed model, it is shown that it is possible to predict the impact of temperature variations on an all-fiber based edge filter.
Some Rather Mechanical Reflections On Symmetry: In Art, Science, Engineering, Mathematics, Etc., Jim Mcgovern
Some Rather Mechanical Reflections On Symmetry: In Art, Science, Engineering, Mathematics, Etc., Jim Mcgovern
Articles
This Inaugural Lecture consists of some of my rather mechanical, being an engineer, reflections on symmetry in diverse areas such as art, science, engineering, mathematics, etc. I explain what symmetry is to me, giving examples with lots of images and mentioning or at least barely referencing art, science, architecture, engineering, heritage, cosmology, bicycles, flight, invention, ingenuity, history, wallpaper, mathematics, typography, structures, regular shapes, coordinate systems, spacetime, thermodynamics and suchlike.
Rampart Roads In The Peat Lands Of Ireland: Genesis, Development And Current Performance, Juan Pablo Osorio, Eric R. Farrell, Brendan C. O'Kelly, Tom Casey
Rampart Roads In The Peat Lands Of Ireland: Genesis, Development And Current Performance, Juan Pablo Osorio, Eric R. Farrell, Brendan C. O'Kelly, Tom Casey
Articles
The construction and improvement of roads on peat lands has always been a challenging task in geotechnical engineering. Rampart roads, which are a particular feature of the bog roads in Ireland, are caused by the excavation of peat from the roadsides over many years for use as a domestic fuel. The historical development of rampart roads and current performance under the added traffic loading is discussed. Various road improvement methods have been applied to improve the road ability to carry traffic and the technical aspects and performance of the methods are discussed. In particular, the performance of the improvement methods …
Force Measurement Methods In Telerobotic Surgery: Implications For End-Effector Manufacture, Dean Callaghan, Mark Mcgrath, Eugene Coyle
Force Measurement Methods In Telerobotic Surgery: Implications For End-Effector Manufacture, Dean Callaghan, Mark Mcgrath, Eugene Coyle
Articles
Haptic feedback in telesurgical applications refers to the relaying of position and force information from a remote surgical site to the surgeon in real-time during a surgical procedure. This feedback, coupled with visual information via microscopic cameras, has the potential to provide the surgeon with additional ‘feel’ for the manipulations being performed at the instrument-biological tissue interface. This increased sensitivity has many associated benefits which include, but are not limited to; minimal tissue damage, reduced recuperation periods, and less patient trauma. The inclusion of haptic feedback leads to reduction in surgeon fatigue which contributes to enhanced performance during operation. Commercially …
A Force Measurement Evaluation Tool For Telerobotic Cutting Applications: Development Of An Effective Characterization Platform, Dean Callaghan, Mark Mcgrath, Eugene Coyle
A Force Measurement Evaluation Tool For Telerobotic Cutting Applications: Development Of An Effective Characterization Platform, Dean Callaghan, Mark Mcgrath, Eugene Coyle
Articles
Sensorized instruments that accurately measure the interaction forces (between biological tissue and instrument endeffector) during surgical procedures offer surgeons a greater sense of immersion during minimally invasive robotic surgery. Although there is ongoing research into force measurement involving surgical graspers little corresponding effort has been carried out on the measurement of forces between scissor blades and tissue. This paper presents the design and development of a force measurement test apparatus, which will serve as a sensor characterization and evaluation platform. The primary aim of the experiments is to ascertain whether the system can differentiate between tissue samples with differing mechanical …
The Effect Of Vibratory Milling On The Powder Properties Of Zinc Oxide Varistors, Maura Kelleher, M.S.J. Hashmi
The Effect Of Vibratory Milling On The Powder Properties Of Zinc Oxide Varistors, Maura Kelleher, M.S.J. Hashmi
Articles
The formation of powders from multi-elemental oxides for the subsequent formation of a green and sintered compact body is a major processing operation in the manufacture of ZnO varistors. The physical and chemical properties of the metal oxides are crucial not only for the formation of a varistor component with optimum microstructure and thus electrical characteristics but also for avoiding the introduction of flaws and reduced yield during subsequent manufacturing stages. The effect of vibratory milling using cylindrical zirconia media on the physical and chemical properties of the mixed multi-elemental oxide additives of a commercial ZnO varistor formulation was studied. …
High-Power Low-Frequency Ultrasound: A Review Of Tissue Dissection And Ablation In Medicine And Surgery, Brendan O'Daly, Edmund Morris, Graham Gavin, John O'Byrne, Garrett Mcguinness
High-Power Low-Frequency Ultrasound: A Review Of Tissue Dissection And Ablation In Medicine And Surgery, Brendan O'Daly, Edmund Morris, Graham Gavin, John O'Byrne, Garrett Mcguinness
Articles
High-power low-frequency ultrasound in the range 20–60 kHz has wide ranging clinical applications in surgical and medical instruments for biological tissue cutting, ablation or fragmentation, and removal. Despite widespread clinical application and common device operating characteristics, there is an incomplete understanding of the mechanism of tissue failure, removal and damage. The relative contribution of cavitation, direct mechanical impact and thermal effects to each process for specific tissue types remains unclear. Different and distinct mechanisms and rates of tissue removal are observed for interaction with soft and hard tissue types. Device operating parameters known to affect the interaction include frequency, peak–peak …
Robots Assist In Treatment Of Stroke Patients, Philip Deering, David Kennedy, James Conlon
Robots Assist In Treatment Of Stroke Patients, Philip Deering, David Kennedy, James Conlon
Articles
Robotic rehabilitation is a field of biomedical engineering which combines precise mechanical design with control technology through the interaction of medical and engineering professionalss to produce a new tool in medical rehabilitation. This article provides an overview of an interactive robot for the medical rehabilitation of stroke victims.
Real-Time Plasma Controlled Chemistry In A Two-Frequency, Confined Plasma Etcher, Vladimir Milosavljevic, Albert R. Ellingboe, Cezar Gaman, John V. Ringwood
Real-Time Plasma Controlled Chemistry In A Two-Frequency, Confined Plasma Etcher, Vladimir Milosavljevic, Albert R. Ellingboe, Cezar Gaman, John V. Ringwood
Articles
The physics issues of developing model-based control of plasma etching are presented. A novel methodology for incorporating real-time model-based control of plasma processing systems is developed. The methodology is developed for control of two dependent variables (ion flux and chemical densities) by two independent controls (27 MHz power and O2flow). A phenomenological physics model of the nonlinear coupling between the independent controls and the dependent variables of the plasma is presented. By using a design of experiment, the functional dependencies of the response surface are determined. In conjunction with the physical model, the dependencies are used to deconvolve the sensor …
Extended Nonnegative Tensor Factorisation Models For Musical Sound Source Separation, Derry Fitzgerald, Matt Cranitch, Eugene Coyle
Extended Nonnegative Tensor Factorisation Models For Musical Sound Source Separation, Derry Fitzgerald, Matt Cranitch, Eugene Coyle
Articles
Recently, shift-invariant tensor factorisation algorithms have been proposed for the purposes of sound source separation of pitched musical instruments. However, in practice, existing algorithms require the use of log-frequency spectrograms to allow shift invariance in frequency which causes problems when attempting to resynthesise the separated sources. Further, it is difficult to impose harmonicity constraints on the recovered basis functions. This paper proposes a new additive synthesis-based approach which allows the use of linear-frequency spectrograms as well as imposing strict harmonic constraints, resulting in an improved model. Further, these additional constraints allow the addition of a source filter model to the …
Effect Of Carbon Black On The Mechanical Performances Of Magnetorheological Elastomers, Lin Chen
Effect Of Carbon Black On The Mechanical Performances Of Magnetorheological Elastomers, Lin Chen
Articles
Several magnetorheological elastomer (MRE) samples, with different weight percentages of carbon black, were fabricated under a constant magnetic field. Their microstructures were observed by using an environmental scanning electron microscope (SEM), and their mechanical performance including magnetorheological (MR) effect, damping ratio and tensile strength were measured with a dynamic mechanical analyzer (DMA) system and an electronic tensile machine. The experimental results demonstrate that carbon black plays a significant role in improving the mechanical performance of MR elastomers. Besides the merits of high MR effect and good tensile strength, the damping ratio of such materials is much reduced. This is expected …
Technology-Aided Participative Methods In Environmental Assessment: An International Perspective, Ainhoa Gonzalez, Alan Gilmer, Ronan Foley, John Sweeney, John Fry
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 …
Lattices In Finite Real Reflection Groups, Colum Watt, Thomas Brady
Lattices In Finite Real Reflection Groups, Colum Watt, Thomas Brady
Articles
For a finite real reflection group, $W$, with Coxeter element $\gamma$ we give a uniform proof that the closed interval, $[I, \gamma]$ forms a lattice in the partial order on $W$ induced by reflection length. The proof involves the construction of a simplicial complex which can be embedded in the type W simplicial generalised associahedron.
Extended Nonnegative Tensor Factorisation Models For Musical Sound Source Separation, Derry Fitzgerald, Matt Cranitch, Eugene Coyle
Extended Nonnegative Tensor Factorisation Models For Musical Sound Source Separation, Derry Fitzgerald, Matt Cranitch, Eugene Coyle
Articles
Recently, shift-invariant tensor factorisation algorithms have been proposed for the purposes of sound souce separation of pitched musical instruments. However, in practice, existing alogorithsm require the use of log-frequency spectrograms to allow shift invariance in frequency which causes problems when attempting to resynthesise the separated sources. Further, it is difficult to impose harmonicity constraints on the recovered basis functions. This paper proposes a new additive synthesis-based approach which allows the use of linear-frequency spectrograms as well as imposing strict harmonic constraints, resulting in an improved model. Futher, these additional constraints allow the addition of a source filter model to the …
A Low Polarization Sensitivity All-Fiber Wavelength Measurement System, Ginu Rajan, Yuliya Semenova, Gerald Farrell, Qian Wang, Pengfei Wang
A Low Polarization Sensitivity All-Fiber Wavelength Measurement System, Ginu Rajan, Yuliya Semenova, Gerald Farrell, Qian Wang, Pengfei Wang
Articles
A low polarization-sensitive all-fiber wavelength measurement system using a twisted macro-bend fiber edge filter together with polarization-insensitive (PI) 3-dB coupler is presented. Eliminating the polarization-dependent loss (PDL) is essential when macro-bending single-mode fiber is utilized as an edge filter. A new bending configuration to eliminate the PDL of a fiber edge filter is proposed in this letter by twisting the fiber by 90deg between two bending sections with equal length. The PDL of this configuration retains a low value even while the bending length is increased to achieve a steeper response for the edge filter. This configuration together with a …
Investigation On Singlemode-Multimode-Singlemode Fiber Structure, Qian Wang, Gerald Farrell, W. Yan
Investigation On Singlemode-Multimode-Singlemode Fiber Structure, Qian Wang, Gerald Farrell, W. Yan
Articles
This paper presents an investigation on a single-mode-multimode-single-mode fiber structure. A one-way guided-mode propagation analysis for the circular symmetry waveguide is employed to model the light propagation and the approximated formulations are derived and evaluated concerning the accuracy. Phase conjunction of the multimode interference within the fiber structure is revealed. A simple way to predict and analyze the spectral response of the structure is presented through the space to wavelength mapping with the derived approximated formulations. The prediction of spectral response is verified numerically and experimentally.
Group Velocity Dispersion Reduction In Fibre-Based Slow-Light Systems Via Stimulated Brillouin Scattering, Ronny Henker, A. Wiatrek, K. U. Lauterbach, Max Ammann, Andreas Schwarzbacher, Thomas Schneider
Group Velocity Dispersion Reduction In Fibre-Based Slow-Light Systems Via Stimulated Brillouin Scattering, Ronny Henker, A. Wiatrek, K. U. Lauterbach, Max Ammann, Andreas Schwarzbacher, Thomas Schneider
Articles
Presented are theoretical investigations and simulations of a reduction of the group velocity dispersion (GVD) in slow-light systems by an optimisation of the gain spectrum of the stimulated Brillouin scattering (SBS). A comparison between a natural Brillouin gain spectrum and a broadened Brillouin gain spectrum with and without two additional losses at its wings is demonstrated. The focus of the theoretical examination was set on the superposition of a gain and two losses with an equal magnitude. Therefore, a low GVD and a high group index change could be achieved and hence, a small pulse distortion and a high time …
Dual-Frequency Dual-Sense Circularly-Polarized Slot Antenna Fed By Microstrip Line, Xiulong Bao, Max Ammann
Dual-Frequency Dual-Sense Circularly-Polarized Slot Antenna Fed By Microstrip Line, Xiulong Bao, Max Ammann
Articles
A new design of a dual-frequency dual circularly-polarized slot antenna is presented. The dual-frequency is achieved using a single-layer microstrip-fed configuration coupled to a modified annular-slot antenna. The dual sense circular-polarization is obtained by four unequal linear slots which augment the annular slot. Experimental results show the proposed antenna has good circular polarization characteristics for both right-hand circular polarization (RHCP) and left-hand circular polarization (LHCP). The 10 dB return loss impedance bandwidths for the lower (RHCP) and higher (LHCP) bands are 26.7% and 11.3%, respectively. The 3 dB axial-ratio bandwidths are 6.1% and 6.0% with respect to 1.5 GHz (RHCP) …
Dual Frequency Dual Circularly-Polarised Patch Antenna With Wide Beamwidth, Xiulong Bao, Max Ammann
Dual Frequency Dual Circularly-Polarised Patch Antenna With Wide Beamwidth, Xiulong Bao, Max Ammann
Articles
A dual-frequency dual-circularly polarised patch antenna with wide beamwidth is proposed. The two-layer structure comprises circular patches with offset circular slots connected to rectangular slots. They provide orthogonal perturbations realising RHCP and LHCP for the lower and upper bands, respectively. The wide beamwidth is realised by extending the substrate beyond the groundplane. Measurements show a maximum beamwidth of 180deg and gains of 3.9 and 0.5 dBic for zenith and 10deg elevation, respectively, for the upper band. The measured beamwidth for the low band is 130deg with a maximum gain of 3.9 and -0.7 dBic for zenith and 10deg elevation, respectively. …
Influence Of Fiber Manufacturing Tolerances On The Spectral Response Of A Bend Loss Based All-Fiber Edge Filter, Pengfei Wang, Gerald Farrell, Yuliya Semenova, Ginu Rajan
Influence Of Fiber Manufacturing Tolerances On The Spectral Response Of A Bend Loss Based All-Fiber Edge Filter, Pengfei Wang, Gerald Farrell, Yuliya Semenova, Ginu Rajan
Articles
It is shown that manufacturing tolerances of the fiber parameters bend radius and NA significantly influence the fiber bend loss performance and spectral response of a fiber-based edge filter. A theoretical model, validated by experimental results, is used to determine the changes in key spectral parameters for an edge filter, resulting from changes within their manufacturing tolerance range, for both the bend radius and NA. Finally is shown that bend-radius tuning during fabrication of such filters is a means of mitigating the effect of manufacturing variations.
Temperature Dependence Of Macrobending Loss In All-Fiber Bend Loss Edge Filter, Pengfei Wang, Yuliya Semenova, Gerald Farrell
Temperature Dependence Of Macrobending Loss In All-Fiber Bend Loss Edge Filter, Pengfei Wang, Yuliya Semenova, Gerald Farrell
Articles
A theoretical model for macrobending-induced temperature dependent loss (TDL) for a standard singlemode fiber (SMF28) with dual coating layers is presented, with good agreement demonstrated between theoretical calculations and experimental results. The impact of temperature on two examples of an all-fiber based edge filter is also investigated theoretically and experimentally and using the developed model, it is shown that it is possible to predict the impact of temperature variations on an all-fiber based edge filter.
Ratiometric Wavelength Monitor Based On Singlemode-Multimode-Singlemode Fiber Structure, Agus Hatta, Gerald Farrell, Qian Wang, Ginu Rajan, Pengfei Wang, Yuliya Semenova
Ratiometric Wavelength Monitor Based On Singlemode-Multimode-Singlemode Fiber Structure, Agus Hatta, Gerald Farrell, Qian Wang, Ginu Rajan, Pengfei Wang, Yuliya Semenova
Articles
An all-fiber ratiometric wavelength monitor for optical wavelength measurement is proposed and is investigated theoretically and experimentally. Two edge filters with opposite slope spectral responses based on singlemode-multimode-singlemode (SMS) fiber structures are developed. A ratiometric wavelength measurement system employing the developed SMS edge filters demonstrates a high discrimination range of 20.41 dB and a potential wavelength measurement resolution of 10 pm over a wavelength range from 1530 to 1560 nm.
High Performance Zno Varistors Prepared From Nanocrystalline Precursors For Miniaturised Electronic Devices, Suresh Pillai, Declan Mccormack, John Kelly, Raghavendra Ramesh
High Performance Zno Varistors Prepared From Nanocrystalline Precursors For Miniaturised Electronic Devices, Suresh Pillai, Declan Mccormack, John Kelly, Raghavendra Ramesh
Articles
An industrially viable solution-based processing route using minimal amounts of solvent has been used to prepare bulk quantity nanopowders (average particle size 15.3 nm) for the fabrication of ZnO varistors. The xerogels, calcined powders and sintered materials were fully characterised. The preparation of varistors from nanopowders has been optimised by studying the effect of temperature on grain growth, densification and breakdown voltage. The varistors are prepared by sintering at 1050 C for 2 hours, a temperature that is significantly lower than that used in the current industrial process. Highly dense varistor discs prepared from the sintered material produce devices, with …
The New Engineer: Between Employability And Social Responsibility, Eddie Conlon
The New Engineer: Between Employability And Social Responsibility, Eddie Conlon
Articles
The reasons behind the demand for what is sometimes called the New Engineer are critically examined and it is argued that a focus on employability alone is not sufficient to prepare socially responsible engineers. By examining issues around work organisation and sustainability it is proposed that engineers need to understand the wider social context in which they work. It is argued that the focus of ethics education should be broadened to focus on the social structure and the way it both enables and constrains socially responsible conduct. There is a call to refocus engineers’ attitudes towards the systems of regulation …
Investigation On The Performance Of Upqc-Q For Voltage Sag Mitigation And Pq Improvement At A Critical Load Point, Malabika Basu, S. P. Das, Gopal Dubey
Investigation On The Performance Of Upqc-Q For Voltage Sag Mitigation And Pq Improvement At A Critical Load Point, Malabika Basu, S. P. Das, Gopal Dubey
Articles
The unified power quality conditioner (UPQC) is one of the major custom power solutions, which is capable of mitigating the effect of supply voltage sag at the load end or at the point of common coupling (PCC) in a distributed network. It also prevents the propagation of the load current harmonics to the utility and improves the input power factor of the load. The control of series compensator (SERC) of the UPQC is such that it injects voltage in quadrature advance to the supply current. Thus, the SERC consumes no active power at steady state. The other advantage of the …
Audio Data Verification And Authentication Using Frequency Modulation Based Watermarking, Jonathan Blackledge, Omar Farooq
Audio Data Verification And Authentication Using Frequency Modulation Based Watermarking, Jonathan Blackledge, Omar Farooq
Articles
An approach to watermarking digital signals using frequency modulation - ‘Chirp Coding’ - is considered. The principles underlying this approach are based on the use of a matched filter to reconstruct a ‘chirp stream’ code that is uniquely robust. The method is generic in the sense that it can, in principle, be used for a variety of different signal (the authentication of speech and biomedical signals, for example). Further, by generating a bit stream that is signal dependent, chirp coding provides a method of self-authentication, which has a wide range of applications including copyright protection and digital rights management. However, …
Quarter-Wave Metal Plate Solar Antenna, S. Shynu, Max Ammann, Brian Norton
Quarter-Wave Metal Plate Solar Antenna, S. Shynu, Max Ammann, Brian Norton
Articles
A novel design of a quarter-wave shorted trapezoidal metal plate solar antenna using high efficiency polycrystalline silicon solar cells is presented. Using the DC conductive parts of the cell as RF antenna elements as well as choosing the radiating element to be a small base trapezoid, better coupling between the feed and shorting plates is ensured and 40.3% size reduction compared to a conventional shorted quarter-wave patch is obtained. The trapezoidal radiating element covers merely 2.7% of the total available illumination area of the solar cell, leaving its efficiency essentially unaffected. The proposed design strategy has been verified by an …
V-Shaped Electro-Optic Response Observed In A Chiral Ferroelectric Smectic Liquid Crystal, V. Manjuladevi, Yuri Panarin, Jang-Kun Song, B. K. Sadashiva
V-Shaped Electro-Optic Response Observed In A Chiral Ferroelectric Smectic Liquid Crystal, V. Manjuladevi, Yuri Panarin, Jang-Kun Song, B. K. Sadashiva
Articles
We report on the observation of V-shaped switching in a ferroelectric liquid crystal cell over a wide range of temperatures. Results of the optical transmittance in the visible region give us the helical pitch for various temperatures of the ferroelectric liquid crystalline compound used. We show that the helical pitch, in addition to the spontaneous polarization (PS) and thickness of the alignment layer of the cell, is an important factor in giving V-shaped switching. A longer or helical compensated mixture gives a better V-shaped switching. © 2008 American Institute of Physics.