Engineering Commons^™

Analysis Of Indentation Loading Of Cortical Bone Using Acoustic Emission Techniques, Ashkan Safari, Ger Reilly, Brendan Mccormack

Conference Papers

In this study, we recorded the number of Acoustic emission (AE) hits and related AE energy during indentation fracture of cortical bone using a PAC PCI-2 card and pico sensor. A threshold value of 43dB was used to filter premature trigger due to background noise. Registered AE hits had more than one count (threshold crossing). Amplifier gain was set at 40dB with a (0.1-1) MHz band pass filter. 8mm cubes of cortical bones were indented in the longitudinal direction at constant crosshead speed of 1 mm min-1 using a large 2D, 50˚ wedge indenter. We hypothesised that signals occurring as …

Bs News

Building Services Engineering

No abstract provided.

Bs News

Building Services Engineering

No abstract provided.

Excellence In Engineering Education, Mike Murphy

Presentations

No abstract provided.

Performance Evaluation Of Video Streaming With Background Traffic Over Ieee 802.11 Wlan Networks, Nicola Cranley, Mark Davis

Conference papers

There is an increasing demand for multimedia streaming applications over WLAN networks. MPEG-4 and H.264 are compression standards targeted at high-quality streamed multimedia services over wireless best-effort IP networks. However, the dynamic nature of wireless networks in terms of fluctuating bandwidth and time-varying delays makes it difficult to provide good quality streaming under such constraints. Multimedia streaming applications are a demanding and challenging service to deliver over wireless networks. There is a trade-off between the capacity of the wireless network and the quality of the multimedia streaming application. In this paper we investigate the effect the background traffic load has …

Probalistic Analysis Of Highway Bridge Traffic Loading, Colin C. Caprani

Other resources

Many bridges of the world’s highway networks have been in service for decades and are subject to escalating volumes of traffic. Consequently, there is a growing need for the rehabilitation or replacement of bridges due to deterioration and increased loading. The assessment of the strength of the existing bridge is relatively well understood, whereas the traffic loading it is subject to, is not as well understood. Accurate assessment of the loading to which bridges may be subject, can result in significant savings for the highway maintenance budgets internationally. In recent years, a general approach has emerged in the research literature: …

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Building Services Engineering

No abstract provided.

Detection Of Microcracks During Bone Cutting Using Acoustic Emission Techniques, Ashkan Safari, Ger Reilly, Brendan Mccormack

Conference Papers

Surgeons may use a number of cutting instruments such as osteotomes and chisels to cut bone during operative procedures. The initial loading of cortical bone during the cutting process results in the formation of microcracks in the vicinity of the cutting zone with main crack propagation to failure occurring with continued loading; microcracking acts as a stimulus for main crack formation and has also been shown to occur during the propagation of the main crack. It has also been reported that Acoustic Emission (AE) is generated due to microcrack formation and crack growth, prior to, and during final fracture in …

An Experimental Technique For Measurement Of Heat Generated During Bone Sawing, Hamid Khalili Parsa, Ger Reilly, Brendan Mccormack

Conference Papers

Orthopaedic bone cutting processes such as osteotomy and hip arthroplasty involve the cutting of one with the aid of various manual and powered cutting instruments including manual and powered bone saws. The extent of surgically induced bone necrosis at the point of the cutting tool and the bone is mainly due to the frictional heat generated by bone cutting. Bone necrosis has an impact on bone regeneration, and the rate of healing of the bone post operation. The threshold temperature for impaired regeneration of bone is in the range of 44°C to 47°C. Overheating also affects the sharpness life of …

Ireland’S Economic Environment:The Scm Context, Edward Sweeney

Practitioner Journals

No abstract provided.

Bologna Process Update: Engineering Education In Ireland, Mike Murphy

Presentations

No abstract provided.

The Human Eye Position Control System In A Rehabilitation Setting, Yvonne Nolan, Ted Burke, C. Boylan, Annraoi De Paor

Articles

Our work at Ireland’s National Rehabilitation Hospital involves designing communication systems for people suffering from profound physical disabilities. One such system uses the electro-oculogram, which is an (x,y) system of voltages picked up by pairs of electrodes placed, respectively, above and below and on either side of the eyes. The eyeball has a dc polarisation between cornea and back, arising from the photoreceptor rods and cones in the retina. As the eye rotates, the varying voltages projected onto the electrodes drive a cursor over a mimic keyboard on a computer screen. Symbols are selected with a switching action derived, for …

Enterprise Strategy Development: A Three-Dimensional Approach To The Role Of Scm, Edward Sweeney, Ciaran Finn

Practitioner Journals

The Irish economy has grown strongly in recent years. This, combined with other factors in the international trading environment, has sharpened the focus on the need for innovative strategies at a national level which can contribute positively from an enterprise strategy development perspective. As traditional manufacturing activity has migrated to lower labour cost economies questions have been raised concerning the role of supply chain management (SCM) in the evolving Irish business environment. This article describes some of the main drivers in terms of both SCM and the changing economic and business environment. It goes on to propose a three-dimensional approach …

Bs News

Building Services Engineering

No abstract provided.

A Case-Based Technique For Tracking Concept Drift In Spam Filtering, Sarah Jane Delany, Padraig Cunningham, Alexey Tsymbal, Lorcan Coyle

Articles

Spam filtering is a particularly challenging machine learning task as the data distribution and concept being learned changes over time. It exhibits a particularly awkward form of concept drift as the change is driven by spammers wishing to circumvent spam filters. In this paper we show that lazy learning techniques are appropriate for such dynamically changing contexts. We present a case-based system for spam filtering that can learn dynamically. We evaluate its performance as the case-base is updated with new cases. We also explore the benefit of periodically redoing the feature selection process to bring new features into play. Our …

The Application Of Advanced Solid Modelling Techniques To The Design Of Precision Air Handling Units For Manufacture, Senan Moynihan

Masters

This thesis investigates the application of ActiveX technology to customise mid range solid modelling software, with a view to exploring the benefits small to medium sized manufacturing companies can experience from its successful implementation. A custom application intended to automate solid modelling software was developed that optimises the product design process and also generates the necessary manufacturing information, including working drawings, for precision air handling units. This was successfully accomplished through research and by integrating Computer Aided Design (CAD) with a custom application using ActiveX technology. A variety of CAD products and associated technologies i.e. solid modelling kernels, were researched …

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Building Services Engineering

No abstract provided.

Sequential Labelling And Acoustic Emission Analysis Of Damage Occurring In Cortical Bone During Indentation Cutting, Ger Reilly, Ashkan Safari, David Taylor, Brendan Mccormack

Conference Papers

When a surgeon uses a wedge shaped blade or an osteotome to cut cortical bone during an operative procedure the bone will fail by a process of microcracking and primary crack propagation. It has previously been observed that crack propagation is dependent on the direction of cutting relative to the main axis of the bone. It has also been observed that microcracks occurring during fracture release acoustic signals that facilitate real-time monitoring of a cutting process. In these novel studies, we labelled damage accumulation during cutting of cortical bone using sequential chelating dyes and we correlated recorded AE signals during …

Electromagnetic Measurement Of Spinal Curvature, Ronan Fitzmaurice, Ted Burke, Annraoi De Paor

Conference Papers

In this paper, we describe an original mathematical technique for calculating the position and orientation of an electromagnetic coil from a minimum of four collinear magnetic field measurements. This problem arose in the development of a system for evaluating the efficacy of inflatable back rafts designed to mitigate complications that arise from the immobilisation of patients with suspected spinal injuries on spinal boards during transport to hospital. Electromagnetic markers are attached to points of interest on the back of an immobilised test subject. Spinal curvature is then measured by passing a magnetometer underneath the board.

Performance Evaluation Of Resource Usage For Unicast Video Streaming Over Ieee 802.11 Wlan Networks, Nicola Cranley, Mark Davis

Conference papers

Multimedia streaming applications are a demanding and challenging service to deliver over wireless networks. Such services have a large impact on the resource requirements of the WLAN. However, there are many variables involved in video streaming, such as the video content being streamed, how the video is encoded and how it is sent. This makes the role of radio resource management and the provision of QoS guarantees extremely difficult. In this paper we investigate the network resource requirements for three scenarios: a single unicast video streaming session; multiple unicast video streaming sessions and finally multiple unicast streaming sessions in the …

An Assessment Of The Audio Codec Performance In Voice Over Wlan (Vowlan) Systems, Miroslaw Narbutt, Mark Davis

Conference papers

In this paper we present results of experimental investigation into the performance of three audio codecs (ITU-T G.711, G.723.1 and G.729A) under varying load conditions on a Voice over WLAN system utilizing the IEEE 802.11b wireless LAN standard. The analysis is based upon a new technique for estimating user satisfaction of speech quality calculated from packet delay and packet loss/late measurements. We also demonstrate the importance of the de-jitter buffer playout scheme for insuring speech quality. From our results we conclude that the use of the G.711 audio codec in conjunction with the new adaptive playout scheme gives the highest …

Bs News

Building Services Engineering

No abstract provided.

Assessing The Quality Of Voip Transmission Affected By Playout Buffer Scheme, Miroslaw Narbutt, Mark Davis

Conference papers

Delay, echo, encoding scheme, and packet loss all influence perceived quality of conversational speech transmitted over packet networks. Therefore, the choice of a buffer algorithm cannot be solely based on statistical loss/delay trade-off metrics. Also subjective “listening tests” or the newer ITU-T PESQ method, which don’t consider the effect of mouth-to-ear delay are inappropriate. We proposed a method for assessing VoIP call quality by extending the ITU-T E-model concept. This method provides a direct link to perceived conversational speech quality by estimating user satisfaction from the combined effect of information loss, delay and echo.

Manufacture Of Near Net Shaped 3-Dimensional Components For Industrial Applications, David Kennedy, Donal Brosnan

Conference Papers

The development of near net shape 3-Dimensional products for industrial applications has been one main goal for Manufacturing Industries over the last few decades. Processes such as polymer blow moulding and its various stages of development, glass forming, extrusion, forging, centrifugal and sand casting, bulge forming and vacuum forming are typical processes that have contributed to this development. Current practices centre on Surface coatings, Rapid Prototyping, laser forming and nanotechnology manufacture of complex 3-D shapes and assemblies. The work described in this paper is a new and highly efficient and cost effective technique for producing 3-Dimensional thin walled shapes by …

Thermal Efficiency Characteristics Of Indirect Evaporative Cooling Systems, Ben Costelloe, Donal Finn

Conference Papers

Recent developments in enhancing heat transfer in cooling towers, together with the success of chilled ceilings, have prompted a review of the evaporative cooling technique. in temperate maritime climates. The thermal efficiency of such systems is a key parameter, as a measure of the degree to which the system has succeeded in exploiting the cooling potential of the ambient air. This paper presents the results of experimental research into the thermal efficiency of a water-side open indirect evaporative cooling test rig designed to achieve low (1-4 K) approach conditions. Secondary efficiencies in the range 0.24-0.76 have been achieved.

Friction And Adhesion In Rigid Surface Indentation Of Nitrile Rubber, Stephen Jerrams

Articles

When a rigid body in the form of a plane strain indentor is forced into an elastomer, the asperities on the surface of the indentor are filled by the softer material. As depth of ingress increases, the rubber displaced into the indentor asperities exhibits stick-slip behaviour. The rubber adheres to the rigid body and if the depth of ingress is held at a maximum, the level of adhesion remains constant despite short-term load relaxation occurring in the rubber.

This text describes the influence of a range of factors on indentation forces and adhesion in rigid indentation of hydrogenated nitrile rubbers. …

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Building Services Engineering

No abstract provided.

Changing To A Student-Centred Paradigm: The Why, What And How, Mike Murphy

Presentations

No abstract provided.

Bs News

Building Services Engineering

No abstract provided.

Bs News

Building Services Engineering

No abstract provided.