Dublin City University. Having a research degree marks you out as someone with both specialist knowledges in your discipline and the ability and commitment to manage and complete a demanding and challenging piece of academic research. As detection and visualisation is a critical aspect of such species pre-concentration and identification systems. A 10 vol. Significantly different electrochemical behaviour and corrosion rates have been found within the PM, WM and HAZ. In terms of photovoltaic cells, the main problem is the lack of efficiency for harvesting the solar energy. Each shear test was then repeated at four different normal loads so as to generate a family of stress-strain curves. Phase 2: Experiments were repeated with the addition of blood so as to replicate a saturated environment as is encountered during operative conditions. A vibration impaction device was developed which housed two 15V DC motors with eccentric weights attached inside a metal cylinder. Modern polymer balls exhibited strain-rate sensitivity while traditional multi-compositional balls exhibited strain dependency. The characteristics of the wax were also analysed in order to optimise the model production process. This system was also designed to be more versatile and affordable than what is currently available commercially, as while these machines are important for studies they are not in common use at present due to their cost. The obtained mechanical properties are not sufficient for high load bearing implants, where the required strength in ranging between 1.5 -150 MPa and compressive stiffness is above 10 MPa. Effect of the temporal thermal field on quality of semi-solid metal formed components. The inspection system is based on the principle of optical triangulation and provides a non-contact method of determining 3D profile of a diffuse surface. PhD Student: Aymen Ben Azouz ABSTRACT. It is also known that if the surface area of the solar cell can be increased, by micromachining for example that more power can be generated. These findings indicated the ability to design a strut architecture within which the stress levels can be varied to a larger degree at the strut surfaces such that cellular attachment and growth can be promoted. Established in June 2018, The DCU Centre of Excellence for Diversity and Inclusion is a central hub for research, advice and knowledge exchange on diversity and inclusion. As the laser beam interaction time increased, the surface roughness of the steel increased for the various pulse energy levels examined. Laser micromachining is commonly used for creating interconnects between active layers (for example glass substrate, hydrogenated silicon, and zinc oxide layers) in photovoltaic cells. DCU Business School is characterised by a vibrant research community and we provide unrivalled research support to postgraduate research students. Variation of the process parameters for this micro and nano-structuring will allow investigation of their influence over surface topology. The sun provides the earth with free energy; however, current methods of harnessing this energy as electricity have some limitations. In our system the optimal frequency of vibration was 60 Hz. In these applications both the internal and external geometry of the scaffold are very important since they have significant effect on mechanical properties, permeability and cell proliferation. Students are given supervision of an expert panel, students are encouraged to attend seminars, present at conferences and publish work in scholarly articles. While we strive to only link you to companies and organizations that we feel offer useful information, DCU does not directly support … While the structure of the surface was seen to retain a conventional crystal arrangement, grain orientation changes were observed in the laser processed region. A new report from Dublin City University’s National Centre for Family Business shows that despite 83% of CEOs reporting their business to be negatively impacted by the COVID-19 pandemic, Irish family businesses have demonstrated resilience and a strong commitment to continuity.. This was used to evaluate the viscosity of semi-solid metals passing through the designed capillary viscometer at injection speeds of 0.075, 0.5, and 1 m/s. The objective of this project was to design and develop a laser based inspection system for the detection of surface defects and to assess its potential for high-speed online applications. From 2005-2013, this took him to war and post-conflict zones in northern Uganda and South Sudan, leading to his book, Imitating Christ in Magwi: An Anthropological Theology (Bloomsbury/T&T Clark, December 2018). In particular, an integrated cooling coil design was shown to provide no improvement over the original design. The requirement for the pump manufacturing industry to move in this direction has increased recently with the introduction of new EU legislation making it a requirement that new higher efficiency levels are met across the industry. The dependence of particle dispersion times, settling times and vortex height on stirring geometry and stirrer speed was found. The newly developed system presented in this thesis, has been used to move test subjects up to 100kg in weight. One was the design and construction of a high temperature capillary viscometer and the second was the modelling of semi-solid metal flow with a view to aiding the design and providing data for comparison purposes. Computational Control of Laser Systems for Micro-Machining. Depending on the geometry, the microfabricated structures have applications in telecommunications, microfluidics, micro-sensors, data storage, glass cutting and decorative marking applications. Algorithms were developed to analyse the data obtained from the scanning of different sample surfaces. What can DCU … The high temperature capillary viscometer has been constructed and has been used for preliminary testing. The system was used to measure the dimensions of the surface defects, such as holes (1 mm), blind holes (2 mm) and notches in different materials. The work covered in this project had the aim of improving the electrical efficiency of a submersible pump. Phase 1: Eighty bovine femoral heads were milled using the Noviomagus bone mill. The aim of this work was to design, build and test a system that could perturb a test subject standing upon it in order to assess their ability to react to these changes. A process mapping investigation was then carried out to determine a range of specific laser processing parameters that melt the surface of the steel. This device can be used in conjunction with standard and plot column chromatography systems. The contribution of manufacturing conditions to ball performance was investigated by conducting extensive prototyping experiments. Normally, in packaging power devices, Aluminium (Al) or Copper (Cu) has been used as a heat sink or baseplate for attaching ceramic substrates that carry the chips and the associated lead structures. Primary components of the developed system consist of a diode laser, CCf15 CMOS camera, and two PC controlled servomotors. Generic system development for marine environmental sensing, Design build and test a novel system for integration and deployment of emerging environmental sensor technologies. A modified surface grain with an ultrafine size of less than 500 nm was observed to be achievable. Effect of Vibration on the Shear Strength of Impacted Bone Graft in Revision Hip Surgery. This would be achieved by rapidly tilting the surface on which the person was standing and then returning it to the horizontal position. Resulting properties from quality improvement such as increased strength, hardness, and stiffness will be investigated. The time has come when it is imperative that society needs begins to rely heavily on renewable energy sources. Use this number to send us... Loan authorization payment changes ; … H13 samples were roughened and chemically etched prior processing to improve the surface absorbance at the CO2 laser wavelength. This work examined the influence of processing parameters on the production of Al-SiC metal matrix composites (MMC) by batch compocasting process. Join our NGM Students to learn how to maximise your Smartphone. However, SSM cast components tends to contain residual porosity, which is extremely detrimental to performance. Another important finding was that at different settings of laser parameters, the modified H13 surface exhibited a range of hardness between 728 and 905 HV0.1. These need to achieve uniform product quality at high throughput speeds. Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. All students were assessed by report submission, multiple choice questions relating to their experiment and questionnaires. Development of a laser based inspection system for surface defect detection, Mohammed Belal Hossain Bhuian (MEng 2002). A newly developed technique of using an angled array of fibres allowed an adjustable resolution to be obtained with the system, with a maximum system resolution of approximately 100 µm (the diameter of the collecting fibre). Research Profiles Search ResultsresearchLorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Such devices can allow pre-concentration of large volume of species and are relatively simple fabricated. Corrosion testing within a 3.5% NaCl solution saturated with CO2 under deoxygenated condition at room temperature (20±2 ˚C), with pH of 4.0±0.3 was examined. Metal Matrix Composite (MMC) is rapidly becoming prime candidates as structural materials in engineering as well as in electronic application. Analysis and Characterisation of the Strain Behaviour of Tissues and the Implications for Scaffold Design. The non-linear viscoelastic response was defined by two values of stiffness, initial and bulk stiffness. Improvement of Efficiency in a Submersible Pump Motor. The results of this study were also compared to other related studies within the field of CBL. A significant part of the work consisted of the design, construction and validation of a specialised quick quench compocaster for this high temperature processing method. There was no change in concepts being between the two versions of the experiments; the only difference was in the methodology of presentation. Mechanical properties were seen to depend on the designed pore shape (architecture), pore size (120, 340 and 600 µm) and loading conditions (with or without loading blocks). Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Automated Control of Laser System for Micro-Machining. Stress distribution and pore size location affect the remodelling processes and different loading conditions may change the maximum stress values and its location. The quality specifications for products and the materials used in them are becoming ever more demanding. Contact DCU By Fax. Laser system parameters investigated included power, P, pulse repetition frequency, PRF, number of pulses, N, and scanning speed, U. EHDF is an equilibrium focusing method for ions, based on establishing a balance between the hydrodynamic and electric forces, what allow that the ion in question will become stationary. Tight focusing was also achieved with this system using a microscope objective lens to produce smaller voxels ranging from 5 to 10 µm in soda-lime glass, fused silica and sapphire samples. Dynamic accuracy of the system was measured at 2μm in the Z-axis (height) and at approximately 10μm in the X and Y axes. This commitment to world-class research is central to the new Research and Innovation Strategy, which sets out a range of specific actions to advance our reputation in that regard. Viscoelastic characterisation of the balls was conducted for a range of impact velocities. From these tests a stirring speed of 150 rpm for water-SiC and 300 rpm for the glycerol/water-SiC system were found to be necessary in order to obtain a uniform distribution of the SiC. The developed system has a scanning table area of 200 by 120 millimetres and a vertical measurement range of five millimetres. Localised corrosion of weld metal (WM) and heat affected zone (HAZ) has mostly been explained by galvanic effects caused by both differences in alloy content and microstructure. Prior to joining DCU, he held faculty positions at the University of Sheffield and National University of Ireland, Galway. Specific work outputs include: Improved channel designs and surface morphology for separation science; Monolithic based pumps and extraction phases within an integrated chip; and Separation of selected and extracted target bio-molecule on integrated chip. The effects of viscosities of 1, 300, 500, 800 and 1000 mPas and stirring speeds of 50, 100, 150, 200, 250 and 300 rpm were investigated. Aims: Studies on soil mechanics have established that when vibration is applied to an aggregate, it results in more efficient alignment of particles and reduces the energy required to impact the aggregate. A spatial resolution of approximately 70 µm and a depth resolution of 60 µm were achieved. Examination of the Stir-Casting Method to Produce Al-SiC Composites. Apart from the CAD designed scaffold structures, computed tomography (CT) scans of trabecular bone samples were collected. Cylindrical samples rotating perpendicular to the laser irradiation direction were used with laser irradiance, exposure time, energy fluence, and pulse width being varied. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. We assist at all stages of a research project, starting with ideas how to get funding for your project, developing your funding proposal and managing your award. Initial investigations with the proprietary materials showed that predicted directional mechanical behaviour can be realised. In CO2 containing environments corrosion failures are often explained by varying tenacity of protective corrosion scales adhesion on different carbon steel microstructures. Our mission is to work with both external companies and our researchers to promote innovation, knowledge transfer and commercialisation of DCU innovations through … Laser processed samples were prepared for metallographic study and were characterised for physical and mechanical properties. Advanced Processing Technology Research Centre, School of Applied Language & Intercultural Studies, School of Theology, Philosophy, and Music, School of Language, Literacy & Early Childhood Education, School of STEM Education, Innovation & Global Studies, School of Nursing, Psychotherapy & Community Health, School of Mechanical and Manufacturing Engineering, European Consortium of Innovative Universities (ECIU), Centre for Talented Youth, Ireland (CTYI), Office of the Vice-President Academic Affairs. A new version of the fused deposition modelling system using wax has been designed and used in this work. DCU Invent is DCU's Innovation and Enterprise Centre based on the main DCU campus. Phase 2: Graft impacted with the addition of vibration in a saturated aggregate displayed lower shear strengths for all normal compressive loads than that of impaction without vibration. Single layers of wax were built up one on top of the other to produce two-dimensional and three-dimensional objects. The graft was then washed using a pulsed lavage normal saline system over a sieve tower. Microchannels dimensions varied greatly also with widths ranging from 81 to 365 µm, depths ranging from 3 to 379 µm and surface roughness between 2 to 13 µm being produced depending on the settings. Beginning in 2005, DCU for Kids began a partnership with the Boomer Esiason Foundation. Development of a Laser Based Surface Profilometer Using the Principle of Optical Triangulation. % reinforced SiC particulate, similar to that used in the aluminium MMC's, was used in the visualisation and computational tests. A strong correlation between irradiance, residence time, depth of processing and roughness of processed samples has been established. Good dimensional correlation between scanned parts (coins, screws, washers, and fibre optic lens moulds) were achieved. This involves providing a comprehensive service to facilitate staff in their research activity. The metrology industry is constantly looking for new ways to accurately and quickly inspect and digitise surface topographies including the calculation of surface roughness parameters and generating point clouds (a collection of 3-dimensional points which describe a surface or surfaces) for modelling or reverse engineering purposes. Biography. The system is capable of measuring the thickness of solid, non-transparent objects using the principle of laser-optical triangulation. This project covers the development of a profilometer using the principle of optical triangulation. This work is concentrated on the laser surface modification of AISI 316L stainless steel and Ti-6Al-4V. A direct link will be made between the cell efficiencies and the surface textures. The developed non-contact online surface-profiling device allows for quick high-resolution surface scanning and inspection. The system was successfully used to measure various materials surface profile, surface roughens, thickness, and reflectivity. Phase 1: Graft impacted with the addition of vibration at all frequencies of vibration showed improved shear strength when compared to impaction without vibration. Numerical models and experimental validation of light propagation and light intensity distribution in 2D microfluidic systems is presented. These included wax phase change temperature, wax viscosity and wax droplet shape during processing, Application of Activity Based Costing for Optimisation of Irish Engineering based SMEs, Micro-Fluidic Chip Based Platforms for Liquid Chromatographic Separations. Completed full automation of this process in LabVIEW code is in progress. The crystallinity and phase detection of the modified surface were conducted using an XRD system with Cu Kα radiation and wavelength of 1.54 Å. Results from these models were compared to experimental results to validate the determined flow geometries and regions of increased concentration. A 1.5kW pulsing CO2 laser is used to investigate the effects of varied laser process parameters and resulting surface microstructure and morphology. This was achieved by instrumenting and creating virtual instruments for these experiments. This thesis deals with the design and development of a new high-speed photoelectronic system. The achieved results show that even though this system was used mainly for 2D scanning, it may also be operated as a limited 3D vision inspection system. A minimum modified H13 average surface roughness, Ra, of 1.9 µm was achieved. However further post processing such as infiltration with biodegradable polymers may allow these structures to be used for scaffold applications. The hardness properties of the modified surface were measured by micro-Vickers diamond indentation. Room temperature (25±C) visual simulations, computer simulations and validation Al-SiC MMC production tests were performed. DCU Business School invites applications for PhD scholarships. We work closely with other DCU units which also support the research activity, such as Invent, HR, Finance, Graduate Studies, Library and ISS. This system furthermore showed that all the metal materials examined were able to reflect a signal of the infrared wavelength. The FDM machine builds the part by extruding semi-molten material through a heated nozzle in a prescribed pattern onto a platform. In a dry aggregate the addition of vibration may be beneficial to the mechanical properties of the impacted pellet. Overall the pore size was seen to be more important than the porosity level in determining the overall maximum stress level. PhD Student:  Syarifah Nur Aqida Binti Syed Ahmad (PhD 2011). Current and future work includes dimensional accuracy, precision and repeatability measurements for the designed system; and related optimisation of geometry of micro-channels for the production of microfluidic and lab-on-a-chip devices to be used in chemical/analytical applications and in separation science. A range of frequencies of vibration were tested, as measured using an accelerometer housed in the vibration chamber. The effectiveness of these CBL techniques was assessed by looking at the performance of students using virtual instrumentation against that of other students from the same class undertaking the traditional mode of the experiments. The model-generated force values from this model exhibited a 95% agreement with the experimental data. A modified surface depth which ranged between 35 and 150 µm was developed on the laser processed H13 samples. Over the last five years, two laser micro-machining processes which allow for the production of channels and voxels with repeatable micrometre level resolution have been developed within the Separation Science Cluster research group at Dublin City University. Preliminary work has illustrated that novel capillary mixing and surface channel morphologies that can be generated with a view to enhancing separation capabilities. This work is targeted on the development of an automated laser machining process with high dimensional accuracy and pre-defined process costing. Practical measurements investigating the directional mechanical properties of the manufactured samples showed trends identical with the results of the Finite Element Analysis (FEA). DCU Strategic Plan, 2017-2022; DCU Governing Authority; Policies; Disclaimer; ... DCU COVID-19 Research & Innovation Hub; Centres & Institutes; Research By Faculty & School; Research Support; Partnerships. Always a lively and highly subscribed event which brings researchers of all experience levels from within and outside of the School together for the day, the COVID-19 pandemic saw this event unfortunately postponed indefinitely last year.