Matthew Doolan

Analysis of Transient Thermal Choking Processes in a Model Scramjet Engine

Shadowgraph flow visualisation and floor static pressure measurements have been used to examine the transient behaviour of a thermally choked combusting flow. Experiments were performed to examine the effect of varying inlet Mach number and fuel-air equivalence ratio on the nature and extent of the interaction. In all cases a sudden increase in static pressure was measured, followed by a highly turbulent region of sonic flow which was seen to propagate upstream along the duct. The nature of the dominant processes causing this pressure discontinuity are still not certain. Some mechanisms which may contribute to this phenomenon are presented. These include separation of the boundary layer in the duct, formation of a detonation and formation of a near-normal shock wave by the region of thermally choked flow.

GeMS: first on-sky results

GeMS, the Gemini Laser Guide Star Multi-Conjugate Adaptive Optics facility system, has seen first light in December 2011, and has already produced images with H band Strehl ratio in excess of 35% over fields of view of 85x85 arcsec, fulfilling the MCAO promise. In this paper, we report on these early results, analyze trends in performance, and concentrate on key or novel aspects of the system, like centroid gain estimation, on-sky non common path aberration estimation. We also present the first astrometric analysis, showing very encouraging results.

Results from the commissioning of the Gemini South Adaptive Optics Imager (GSAOI) at Gemini South Observatory

We present the results from the commissioning of the Gemini South Adaptive Optics Imager (GSAOI). Capable of delivering diffraction limited images in the near-infrared, over an 85′′ ×85′′ square field-of-view, GSAOI was designed for use with the Gemini Multi-Conjugate Adaptive Optics (GeMS) system in operation at the Gemini South Observatory. The instrument focal plane, covered by an array of four HAWAII-2RG detectors, contains 4080×4080 pixels and has a plate scale of 0.02′′ – thus capitalizing on the superb image quality delivered by both the all-refractive optical design of GSAOI and the Gemini South MCAO system. Here, we discuss our preliminary findings from the GSAOI commissioning, concentrating on detector characterization, on-sky performance and system throughput. Further specifics about the Gemini MCAO system can be found in other presentations at this conference.

GMT Integral-Field Spectrograph (GMTIFS) conceptual design

The Giant Magellan Telescope (GMT) Integral-Field Spectrograph (GMTIFS)c is one of six potential first-light instruments for the 25m-diameter Giant Magellan Telescope. The Australian National University has completed a Conceptual Design Study for GMTIFS. The science cases for GMTIFS are summarized, and the instrument capabilities and design challenges are described. GMTIFS will be the work-horse adaptive-optics instrument for GMT. It contains an integral-field spectrograph (IFS) and Imager accessing the science field, and an On-Instrument Wave-Front Sensor (OIWFS) that patrols the 90 arcsec radius guide field. GMTIFS will address a wide range of science from epoch of reionization studies to forming galaxies at high redshifts and star and planet formation in our Galaxy. It will fully exploit the Laser Tomography Adaptive Optics (LTAO) system on the telescope. The tight image quality and positioning stability requirements that this imposes drive the design complexity. Some cryogenic mechanisms in the IFS must set to ~ 1 μm precision. The Beam-Steering mechanism in the OIWFS must set to milli-arcsecond precision over the guide field, corresponding to ~ 1 μm precision in the f/8 focal plane. Differential atmospheric dispersion must also be corrected to milli-arcsecond precision. Conceptual design solutions addressing these and other issues are presented and discussed.

Identifying variation in sheet metal stamping

This work looks at two different “Design of Experiments”(DoE) methods for defining an operating window in the sheet metal stamping process. The first involves the use of replicates at the different experimental points, while the second is a nonreplicated method. The two methods are compared by looking at the relationship results produced and the indication of variation in the process. It is found that the results from both the methods are very similar. However, the replicated method provides a greater level of confidence in the results. In the stamping process, where performing large numbers of replicates is expensive in both time and money, the nonreplicated method provides a cost effective way of understanding the process.

New Insights into the Australian Automotive Recycling Business

Eight automotive dismantlers/parts recyclers across News South Wales, South Australia and Victoria were interviewed to obtain an understanding of material flows and influences within the Australian automotive recycling system. This paper gives new insights into the current automotive recycling business and its operations by presenting and analysing some key quantitative and qualitative data that was collected through these interviews.

Operational Challenges in the Automotive Recycling Business: A System Dynamics Perspective

Despite advances in automotive recycling policies and technologies, achieving 95% recovery potential in real world terms remains a major challenge. The purpose of this paper is to explore the root causes for this system-level impediment. The paper finds that the five basic operational challenges facing the automotive recycling business are not only the major hurdle in attaining full recycling potential, they also underline the sustainability of the industry. The paper then concludes that in order to sustain the industry and improve the recycling performance, policy makers and industry stakeholders should regard these challenging areas as leverage points into the system.

Characterization and performance of HAWAII-2RG focal plane arrays for NIFS and GSAOI

Large-area near-infrared focal-plane detector arrays constructed from one and four Rockwell Science Center HAWAII- 2RG HgCdTe detectors have been characterized for use in the NIFS and GSAOI instruments recently developed for the Gemini telescopes by the Australian National University. We present details of the detector characterization and compare the performance of five distinct devices with respect to read noise, dark current, and stability in systems based on ARC/SDSU Gen-3 controllers. Advanced operating modes of the H2RG were implemented including enhanced clocking and independent On-Detector Guide Windows for GSAOI. Detector performance using these features and the impact of multiple guide-window reads on long integrations are explored. We also discuss measurement of intra-pixel coupling and its impact on pixel-well capacity, gain, and image quality for these devices.

Use of Image Recognition Techniques in the Analysis of Sheet Metal Forming Force Signature Curves

A new method of metal stamping force signature analysis is presented, based on the image recognition technique Point Distribution Models (PDMs). The approach is shown to be an effective method for analysing force signatures, able to identify not only the occurrence of part failures, but also changes in lubrication, material and process settings.

The influence of joint technologies on ELV recyclability

Stricter vehicle emission legislation has led to the increasing use of lightweight materials and multi-material concepts to reduce the vehicle mass. To account for the complexity of multi-material vehicle designs, the choice of joining techniques used is becoming more diverse. Moreover, the different material combinations, and their respective joining methods play an important role in determining the potential of full material separation in a closed-loop system. This paper evaluates the types of joining technologies used in the automotive industry, and identifies those that hinder the sorting of ELV materials. The study is based on an industrial shredding trial of car doors. Observations from the case study showed that steel screws and bolts are increasingly used to combine different material types and are less likely to be perfectly liberated during the shredding process. The characteristics of joints that lead to impurities and valuable material losses, such as joint strength, material type, size, diameter, location, and protrusion level, can influence the material liberation in the current sorting practices and thus, lead to ELV waste minimisation. Additionally, the liberation of joints is also affected by the density and thickness of materials being joined. Correlation analyses are carried out to further support the influence of mechanical screws and bolts on material separation efficiencies. The observations are representative of the initial phases of current global ELV sorting practices.