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Articles 1 - 7 of 7

Full-Text Articles in Engineering

A New High Power Parallel Converter Scheme For Active Power Filters, Malabika Basu, S. P. Das, Gopal Dubey Jul 2004

A New High Power Parallel Converter Scheme For Active Power Filters, Malabika Basu, S. P. Das, Gopal Dubey

Articles

A new topology for efficient utilisation of parallel converters as VAR compensators and active power filters (APF) for high power loads is proposed. Because of limited power handling capacity of individual devices, paralleling is the choice to increase rating of equipment, while keeping the THD of the current at the PCC within the agency specified standards. It has been reported in the literature that paralleling several converters, rather than switches, is more reliable in sharing of load. From this perspective, multilevel converters carry lot of weight, as their typical power circuit configuration limits the stress on individual devices to an …


A System For Monitoring Pressures And Spinal Curvature In Spinally Injured People Immobilised On A Spinal Raft, Ruairí De Fréin, Eoin Flinn, Ted Burke May 2004

A System For Monitoring Pressures And Spinal Curvature In Spinally Injured People Immobilised On A Spinal Raft, Ruairí De Fréin, Eoin Flinn, Ted Burke

Articles

We present a system designed to study the pressure at various ‘hot spots’ on the back of the body and the deformation of the spine experienced by a patient when strapped to a spinal board, and the potential alleviation of both by the addition of an inflatable “spinal raft” (or other similar device). In measuring pressure we devised a system of air-filled sacks interfaced with a PC. Each sack, placed under a particular key point on the body, is inflated until its faces just begin to separate and a switch thereby opens. The pressure reading is then captured and displayed …


A Vocalisation-Based Drawing Interface For Disabled Children, Ted Burke May 2004

A Vocalisation-Based Drawing Interface For Disabled Children, Ted Burke

Articles

In our work with disabled children at Ireland’s National Rehabilitation Hospital, a problem we have experienced in the facilitation of art activities is that traditional art materials and standard computer drawing programs sometimes prove inaccessible. In this paper, an original system, called “PaintMyVoice” is presented which facilitates the creation of two or three-dimensional images using a variety of novel input modalities. In particular, vocalisations can be used to create original images of a variety of objects, including trees, flowers and landscape elements. Additional input to the system can optionally be provided via mouse, keyboard, switch interface or digital camera depending …


Mechancial Characterization Of Unplasticised Polyvinylchloride Thick Pipes Using Electronic Speckle Pattern Interferometry, Emilia Mihaylova, Benjamin Potelon, Guntaka Tulasi Sridhar Reddy, Vincent Toal, Ciaran Smith Jan 2004

Mechancial Characterization Of Unplasticised Polyvinylchloride Thick Pipes Using Electronic Speckle Pattern Interferometry, Emilia Mihaylova, Benjamin Potelon, Guntaka Tulasi Sridhar Reddy, Vincent Toal, Ciaran Smith

Articles

In this work a number of techniques (electronic speckle pattern interferometry, holographic interferometry, strain gauge and finite element method) are brought to bear in order to establish consistency in the results of strain measurement. This is necessary if optical nondestructive testing methods, such as those used here, are to gain acceptance for routine industrial use. The FE model provides a useful check. Furthermore, ESPI fringe data facilitates the extension of FE models, an approach that is of growing importance in component testing. The use of in-plane and out-of-plane sensitive electronic speckle pattern interferometry (ESPI) for non-destructive material characterization of thick …


Power Coupling Between Two Step-Index Multimode Fibers Of Different Numerical Apertures With An Angular Misalignment, Cheng Gao, Gerald Farrell Jan 2004

Power Coupling Between Two Step-Index Multimode Fibers Of Different Numerical Apertures With An Angular Misalignment, Cheng Gao, Gerald Farrell

Articles

Coupling efficiency between two step- index multimode fibers of different numerical aper- tures with an angular misalignment is calculated. The theory is presented using radiometry and geometrical optics. The limit case of the calculation is consistent with a previously published result. The results may be useful for applications such as power launching between two types of fibers with different numerical apertures for example silica fiber and plastic optical fiber(POF) and with an angular misalignment.


Liquid Crystal Based Optical Switches, Yuliya Semenova, S. Dovgalets, Yuri Panarin, Gerald Farrell Jan 2004

Liquid Crystal Based Optical Switches, Yuliya Semenova, S. Dovgalets, Yuri Panarin, Gerald Farrell

Articles

Optical switches using two electro-optical effects in liquid crystals are proposed and investigated for incorporation in a switch matrix for optical networks. These two devices employ selective reflection in cholesteric layers and total reflection at the border between glass and nematic liquid crystal. Prototypes of these switches have been designed and their parameters have been investigated. Initial results suggest the switching contrast ratio of 38.5 and 42 dB, respectively, with insertion loss about 2.3…2.9 dB for polarized light.


On The Empirical Balanced Truncation For Nonlinear Systems, Marissa Condon, Rossen Ivanov Jan 2004

On The Empirical Balanced Truncation For Nonlinear Systems, Marissa Condon, Rossen Ivanov

Articles

Novel constructions of empirical controllability and observability gramians for nonlinear systems for subsequent use in a balanced truncation style of model reduction are proposed. The new gramians are based on a generalisation of the fundamental solution for a Linear Time-Varying system. Relationships between the given gramians for nonlinear systems and the standard gramians for both Linear Time-Invariant and Linear Time-Varying systems are established as well as relationships to prior constructions proposed for empirical gramians. Application of the new gramians is illustrated through a sample test-system.