Engineering Commons^™

A Comparative Study Of Zn-Mn Electrodeposition From Deep Eutectic Solvents And Aqueous Electrolytes, Jelena Bajat, Mihael Bucko, David Culliton, Tony Betts

Conference Papers

The production of Zn-Mn coatings with high Mn and low oxygen content from additive free choline chloride/urea deep eutectic solvent (DES) is reported in this work. Alloy coatings containing high Mn contents (~30 at.% Mn) show the highest corrosion resistance amongst zinc alloys [1]. However, in order to obtain Mn-rich deposits on steel from a simple aqueous bath, a significant cathodic polarization or high deposition current density is necessary. Under such conditions, the Zn 2+ reduction reaction is under diffusion control, leading to the formation and growth of dendrites. In addition intensive hydrogen evolution significantly reduces the current efficiency, often …

Pump Design And Development For High Shear Grout Mixing Applications, John Kijak, David Kennedy

Conference Papers

No abstract provided.

A Collagen‐Glycosaminoglycan‐Fibrin Scaffold For Heart Valve Tissue Engineering Applications, Claire Brougham, Stefan Jockenhoevel, Thomas Flanagan, Fergal O'Brien

Conference Papers

The field of heart valve biology and tissue engineering a heart valve continue to expand. The presentatio ns at this meeting reflect the advances made in both areas due to the multi-disciplinary approach taken by many laboratories.

Development Of A Mobile High Shear Colloidal Grout Pump For The Construction Industry, John Kijak, David Kennedy

Conference Papers

The aim of this project was to design and develop a group pump and solve associated technical issues for a construction company in Ireland. The design is based on a high shear colloidal group mixing and pumping rig. The initial machine has failed in terms of bearing and seal performance, has high manufacturing costs and is poorly designed.

To account for these issues, extensive research of the design features of grout mixing units from various competitors and suppliers was carried out by research and field studies at trade fairs. Using the information gathered, and incorporating improvements into the existing design, …

The Equi-Biaxial Fatigue Characteristics Of Epdm Under True (Cauchy) Stress Control Conditions, Mark Johnson, Ray Ekins, Niall Murphy, Stephen Jerrams, John Hanley

Conference Papers

ABSTRACT: Strain amplitude control is most often employed when carrying out fatigue testing of rubber components. Often the design engineer requires fatigue test data that is based on load amplitude control. This is analogous to engineering or nominal stress amplitude control. This usually makes it easy to maintain the load within the specified test limits during extended testing. Values of true stress and strain can be obtained from this approach, but the magnitudes of the maximum true stresses in these tests increase with accumulated cycles, whereas the equivalent maximum engineering stress values remain constant. This is easily demonstrated in the …

The Equi-Biaxial Fatigue Characteristics Of Epdm Under True (Cauchy) Stress Control Conditions, Mark Johnson

Conference Papers

Strain amplitude control is most often employed when carrying out fatigue testing of rubber components. Often the design engineer requires fatigue test data that is based on load amplitude control. This is analogous to engineering or nominal stress amplitude control. This usually makes it easy to maintain the load within the specified test limits during extended testing. Values of true stress and strain can be obtained from this approach, but the magnitudes of the maximum true stresses in these tests increase with accumulated cycles, whereas the equivalent maximum engineering stress values remain constant. This is easily demonstrated in the uniaxial …

The Effect Of Microstructure On The Dynamic Equi-Biaxial Fatigue Behaviour Of Magnetorheological Elastomers, Yanfen Zhou, Stephen Jerrams, Tony Betts, Lin Chen

Conference Papers

Dynamic equi-biaxial fatigue behaviour of isotropic and anisotropic magnetorheological elas-tomers (MREs) based on a silicone rubber matrix was investigated using the bubble inflation method. Con-stant engineering stress amplitude was used as the control mode and samples were fatigued over different stress ranges between 0.75MPa and 1.4MPa. S-N (Wöhler) curves showing plots of stress amplitude (σa) ver-sus cycles to failure (N) are presented. Stress-strain behaviour throughout the fatigue process is described. Elastic modulus (E*) was studied for the specific cycles measured. It was found that anisotropic MREs exhi-bited greater fatigue resistance than isotropic MREs for a given magnetic particle content. Stress …

Real Time Shrinkage Studies In Photopolymer Films Using Holographic Interferometry, Mohesh Moothanchery, Izabela Naydenova, Viswanath Bavigadda, Suzanne Martin, Vincent Toal

Conference Papers

Polymerisation induced shrinkage is one of the main reasons why photopolymer materials are not more widely used for holographic applications. The aim of this study is to evaluate the shrinkage in an acrylamide photopolymer layer during holographic recording using holographic interferometry. Shrinkage in photopolymer layers can be measured by real time capture of holographic interferograms during holographic recording. Interferograms were captured using a CMOS camera at regular intervals. The optical path length change and hence the shrinkage were determined from the captured fringe patterns. It was observed that the photopolymer layer shrinkage is in the order of 3.5%.

Investigation Of A New Material For Heart Valve Tissue Engineering, Claire Brougham, Nian Shen, Allison Cudsworth, Thomas Flanagan, Stefan Jockenhoevel, Fergal O'Brien

Conference Papers

No abstract provided.

Effect On The Processing Characteristics Of Zno Varistors Produced Using Vibratory Milling, Maura Kelleher, M.S.J. Hashmi

Conference Papers

Abstract. Each manufacturing stage in the production of zinc oxide varistors from powder preparation to the final encapsulated device is important not only for the formation of the varistor component with optimum microstructure and thus electrical characteristics but also for avoiding the introduction of flaws and reduced yield. In this paper the authors describe and discuss the effect of multi-elemental oxide additives having been milled for different durations using a vibratory mill with cylindrical zirconia media on the powder characteristics of the subsequent processing stages. A commercial ZnO varistor formulation was used. The subsequent processing stages that are given particular …

Creating A Uniform Magnetic Field For The Equi-Biaxial Physical Testing Of Magnetorheological Elastomers; Electromagnet Design, Development And Testing., Dave Gorman, Stephen Jerrams, Ray Ekins, Niall Murphy

Conference Papers

No abstract provided.

Testing, Modelling And Validation Of Numerical Model Capable Of Predicting Stress Fields Throughout Polyurethane Foam, Conor Briody, Barry Duignan, Stephen Jerrams

Conference Papers

Wheelchair seating systems are specialised for a number of reasons as users can have impaired mobility, which increases the possibility of pressure build up. These areas of high pressure frequently occur in the trunk region under the bony prominences known as the Ischial Tuberosities (IT), pressure ulcers may occur consequently. Polyurethane foam has been in use for some time in wheelchair seating systems as it exhibits good pressure relieving capabilities in most cases. However, little quantitative research has gone into foamed polymers, in comparison with conventional elastomeric materials. This lack of knowledge can ultimately lead to more time being spent …

Characterisation, Modelling And Simulation Of Flexible Polyurethane Foam, Conor Briody, Barry Duignan, Stephen Jerrams

Conference Papers

Flexible polyurethane foam is an open-celled polymeric material that exhibits strain rate and temperature effects. It has found various applications in areas including the packaging, medical, sports, aerospace and aeronautical industries. Polyurethane foam is ubiquitous in seating applications and finds particular use in specialised wheelchair seating where customised seating solutions are required which can provide proper comfort and support without the risk of developing pressure ulcers. Proper seating design is critical for users if this problem is to be avoided, but a lack of quantitative knowledge of this material’s behaviour has limited its effectiveness. The objectives of the work presented …

Process Refinement Through Design Of Experiments (Taguchi) To Reduce Porosity Levels Of Thin Flame Spray Nicrbsi Coatings On Cast Aluminium Alloys, David Culliton, David Kennedy, Tony Betts

Conference Papers

Thin(16matrix of key deposition parameters was constructed to develop the optimum spray parameters. The effects of parameter variations on the porosity levels of these coatings were assessed. Key parameter interactions were reported. Quantifiable interactions between the selected parameters were noted for the LM24 substrate. However, on the LM25 substrate these interactions were much less defined. Corrosion performance of the optimised coatings, based on electrochemical impedance spectroscopy, was reported. The presence of through-pores in the coatings were shown to reduce the corrosion resistance of the coated systems by a factor of 10, in dilute NaCl solutions, compared to bulk 316L stainless …

Review Of The Maxus 8 Sounding Rocket Experiment To Investigate Solidification In A Ti-Al-Nb Alloy, Robin Mooney, David Browne, Olga Budenkova, Yves R. Fautrelle, Ludo Froyen, Andrey Kartavykh, Stephan Rex, Burkhard Schmitz, Daniella Voss, Shaun Mcfadden

Conference Papers

A review of the MAXUS 8 sounding rocket microgravity experiment to investigate solidification structures in a Ti-Al-Nb intermetallic alloy is presented. The experiment was part of the Intermetallic Materials Processing in Relation to Earth and Space Solidification (IMPRESS) EU FP6 project. Key objectives were to investigate columnar and equiaxed solidification, and to achieve Columnar-to-Equiaxed Transition (CET) in the alloy. A microgravity experiment was designed to achieve this using a controlled power-down method. Two alloys were tested: one inoculated with a grain refiner and the other without grain refinement. Unrefined samples displayed axial and radial columnar growth. Boride inoculated samples displayed …

Development Of A Friction Testing Apparatus For Demoulding Force Prediction, Kevin Delaney, David Kennedy, G. Bissacco

Conference Papers

Friction between replication tools and replicated parts determines the force required to demould the part and also the stresses which develop in both the tool and the part during the demoulding process. Standardized equipment and procedures have been developed which strive to improve the repeatability and reproducibility of friction tests. Specific test standards, describing sled-type tests, include JIS K 7125, ISO 8295 and ASTM D1894. However these tests do not produce results which are representative of the conditions typically found within replication tools such as injection moulds or embossing tools. This paper reviews how this challenge has been addressed by …

Big Challenges In Designing Small Parts For Mass Production, Kevin Delaney, David Kennedy

Conference Papers

Micro manufacturing involves the production of parts or products with features on a micro scale. The technology is used to produce parts for several business sectors which have experienced dramatic growth in recent years and forecasts are that this growth will continue in the years ahead. With the loss of traditional manufacturing jobs to lower-cost locations many companies in Ireland see micro manufacturing as having significant potential to preserve and increase revenue. A move into micro manufacturing will present significant opportunities for those companies willing to take the risk of producing parts with micro dimensions. Such a transition is a …

Design Issues For Therapeutic Ultrasound Angioplasty Waveguides, Declan Noone, Graham Gavin, Garrett Mcguinness

Conference Papers

Therapeutic ultrasound angioplasty is a new minimally invasive cardiovascular procedure for disrupting atherosclerotic lesions. Mechanical energy is transmitted in the form of ultrasound waves via long, flexible wire waveguides navigated to the lesion site through the vascular system. The underpinning principle of this technology is that plaque may be disrupted through a combination of direct contact ablation, pressure waves, cavitation and acoustic streaming, which all depend on the amplitude and frequency of displacements at the distal tip of the wire waveguide. This study identifies a number of key design issues for clinical devices of this type, and describes testing procedures …

The Effect Of Oil Swelling On The Fatigue Life Of Elastomers Subjected To Cyclic Bubble Inflation, Niall Murphy, John Hanley, Stephen Jerrams, Ali Hassan

Conference Papers

This paper describes the behaviour of rubber in multi-axial fatigue, with respect to oil resistance. A series of tests were carried out on EPDM specimens subjected to varying degrees of swelling. The control methodology and the loading mechanism employed in the testing of elastomers using dynamic multi-axial bubble inflation are outlined. Swollen specimens were prepared by immersing them in reference mineral oil. Specimens were cycled to failure and the results were analysed. The number of cycles to failure for a given engineering stress amplitude was plotted for both dry (unswollen) and swollen specimens. Fracture surfaces for each set of specimens …