Publications by authors named "Dirk Pons"

NEED-The effect of dimensional variability of sheet thickness (tolerance) and tool misalignment is poorly understood for the clinching process. Finite element analysis (FEA) is valuable but requires a lot of and is difficult to verify in this situation due to the asymmetrical geometry and nonlinear plasticity. OBJECTIVE-The objective of this work was to determine the effect of thickness tolerance, tool misalignment and sheet placement (top vs.

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3D Printed Injection Moulds (3DIM), commonly used for low volume production and prototyping purposes, are known to fail abruptly and have a comparatively shorter life than conventional moulds. Investigating the underlying critical factors affecting failure may help in reducing the risk of abrupt failures and possibly prolong the 3DIM tool life. A hypothesis that the cooling time of the Injection Moulding (IM) process is a critical factor for 3DIM tool failure has been proposed.

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Background-The visual inspection of aircraft parts such as engine blades is crucial to ensure safe aircraft operation. There is a need to understand the reliability of such inspections and the factors that affect the results. In this study, the factor 'cleanliness' was analysed among other factors.

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Objective: Nitrous oxide (Entonox) and methoxyflurane (Penthrox) are inhaled analgesics administered in paramedicine. Occupational exposure to nitrous oxide has been associated with negative health effects, and may inhibit professional capability. The effect of occupational exposure to methoxyflurane has not yet been clearly determined.

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Objectives: Ambulance officers administering methoxyflurane as an inhalational analgesic may be exposed to trace vapor. Fluoride is a methoxyflurane metabolite, and has been associated with acute renal failure in anesthesia patients and skeletal fluorosis with chronic elevated serum levels from other sources. However, there has been no direct measurement of serum fluoride in occupationally exposed ambulance officers.

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Background: Polymer-based 3D Printed Injection Mould (3DIM) inserts are used as a cost-effective method for low volume injection moulding (50-500 parts). However, abrupt failure leading to a short tool life is a common shortcoming of 3DIM. Need: The underlying causes of raised feature failures on 3DIM are not well known.

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Successful implementation of Health and Safety (H&S) systems requires an effective mechanism to assess risk. Existing methods focus primarily on measuring the safety aspect; the risk of an accident is determined based on the product of severity of consequence and likelihood of the incident arising. The health component, i.

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Aim: Historically methoxyflurane was used for anaesthesia. Evidence of nephrotoxicity led to abandonment of this application. Subsequently, methoxyflurane, in lower doses, has re-emerged as an analgesic agent, typically used via the Penthrox inhaler in the ambulance setting.

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Background: communication is important for project teams. There is a need to better understand how members respond to communication at project meetings, and how this affects the team roles the participants adopt.

Methods: observational data were collected from (a) two engineering organisations and (b) five university engineering student teams.

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Team communication plays a vital role in engineering management, however, there is a paucity of work that examines how team roles emerge as a response to the communicative processes between participants. This research explored role adoption using qualitative methods comprising observations, questionnaires and semi-structured interviews. Five student teams doing final year projects at a university in New Zealand were observed during the academic year and then interviewed at the final stage of project completion.

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One of the difficulties with bobbin friction stir welding (BFSW) has been the visualisation of microstructure, particularly grain boundaries, and this is especially problematic for materials with fine grain structure, such as AA6082-T6 aluminium as here. Welds of this material were examined using optical microscopy (OM) and electron backscatter diffraction (EBSD). Results show that the grain structures that form depend on a complex set of factors.

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Recording of team meeting's processes with electronic devices can be problematic because of the invasiveness of the process: issues with privacy; interpretation difficulty with noise or quiet speech; and distortion of participants' behaviour. There is a need for less intrusive methods. We developed the interaction diagram method by extending the directed graph nature of sociograms to capture the time sequence of events, including the identification of the person, communication behaviour, and duration of interactions.

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