Modelling of porosity defects in high pressure die casting with a neural network

High Pressure Die Casting (HPDC) is a complex process that results in casting defects if configured improperly. However, finding out the optimal configuration is a non-trivial task as eliminating one of the casting defects (for example, porosity) can result in occurrence of other casting defects. The industry generally tries to eliminate the defects by trial and error which is an expensive and error -prone process. This paper aims to improve current modelling and understanding of defects formation in HPDC machines. We have conducted conventional die casting tests with a neural network model of HPDC machine and compared the obtained results with the current understanding of formation of porosity. While most of our findings correspond well to established knowledge in the field, some of our findings are in conflict with the previous studies of die casting.

Constructing wikis as a platform for online collaboration in an e-learning environment

Previous studies conclude that finding a collaborative tool to suit the e-Iearning environment adequately is quite a task. Consequently, research has been conducted for this very purpose, to trial the use of wikis as a platform to support collaboration in a way that students will embrace and adopt for regular use. The wiki is easily accessible, requires no software and allows its contributors to feel a sense of responsibility and ownership. However there are wiki related challenges that have yet to be researched in the online e-Iearning environment. Possible intrusions, no opinion control, user hostility, and unintentional deletions or editing all require further investigation. This paper will further research the wiki environment in the tertiary e-Iearning setting, as well as consider wiki moderation, member authentication, and interest sustainability to support this community focused collaborative tool. Relevant results from the current case study are explored whilst delivering meaningful data, thus providing an insight into how wikis are an appropriate platform to incorporate in the online collaborative environment.

Employing wikis for online collaboration in the e-learning environment: case study

This paper examines the various ways in which students reflect on their very recent experiences in collaborating in an online e-learning environment. Wikis, fully editable Websites, are easily accessible, require no software and allow its contributors, in these case students, to feel a sense of responsibility and ownership. Wikis are everywhere, but, unfortunately, the online literature has not yet begun to focus enough on wikis (Mattison 2003). Whereas students are used to the WebCT based university Elearning environment, Deakin Studies Online (DSO), this case study, completed in Nov 2004, was conducted to test the wiki platform as a means of online collaboration in the tertiary education environment. A full analysis of the results is presented, as are recommendations for improving the platform in an effort to employ wikis and utilize them to their full and absolute potential.

Modelling factors of square tubes in high speed bending situations

Accurate finite element crash simulations of side impact depend upon a thorough understanding of dynamic tube bending. There is a need to understand the dynamic bending mode of square sections (equivalent of automotive structural parts) to obtain a greater confidence in CAE. This work varied strain rate and material definitions, such as Cowper-Symonds vs Zerilli-Armstrong, as well as initial velocity and yield strength. The results show that most of the plastic work is done between strains rates of 30 ¿ 300/s and strains up to 0.3. Peak strain rates were marginally above 1000/s with maximum strain greater than 1. When the strain rate definition and material model were modified, it was shown that a higher yield stress produced a higher reaction force. These results would suggest that the strain rate sensitivity needs to be carefully identified for accurate crash simulations.

The current pattern of hepatitis B virus infectiion in Australia

Summary. There is little recent data of the seroprevalence of hepatitis B in Australia. We have surveyed a large cohort of endoscopy patients attending a teaching hospital in central Sydney, and related the presence of hepatitis B virus (HBV) markers with putative risk factors for exposure using the SAS statistical package. Of the 2115 patients tested: 2.1% (45/2115) were HBV surface antigen positive, 0.75% (14/2115) viraemic, 9.5% (200/2115) anti-HBs and anti-HBc positive, 20.1% (430/2115) vaccinated (anti-HBs only) and the remaining 70% were susceptible. The adjusted OR of HBV infection was significantly increased in patients who had been diagnosed with human immunodeficiency virus (36.3-fold), born in Asia or Pacific islands (12.4-fold), born in North Africa, Middle East & Mediterranean countries (6-fold) or born abroad elsewhere in the world (2.7-fold), had household contact with someone diagnosed with hepatitis between 1980 and 1990 (3.9-fold), injected drugs between 1980 and 1990 (4.4-fold), resided in a military establishment for 3 months (2.3-fold) or in a hospital for 3 months (2.2-fold), never been vaccinated for hepatitis B (2.8-fold), received blood transfusion due to an accident and/or a haemorrhage (1.92-fold) and finally been a male gender (1.59-fold). The prevalence of HBV in this hospital population was higher than predicted on the basis of notifications to the passive surveillance scheme. Most HBV patients had multiple risk factors for infection, but the hierarchy of odds ratios provides a rational basis for targeted programmes to identify asymptomatic HBV carriers who might benefit from treatment.

Project quality management in virtual environments : a primer

The rise of geographically dispersed project teams enabled by technology has made project quality management a significant challenge for organizations. This paper uses findings from a project on geographically dispersed, cooperating SMEs in the building trade, to explore whether concepts and artefacts from the Rational Unified Process® (RUP®) software development approach could be adapted and used to better manage quality in virtual projects. Our future research aims to explore the use of RUP artefacts in a virtual environment and their impact on
project management and quality.

Food and move project, promoting healthy eating & physical activity in a secondary school setting, pat 1: baseline data, interventions and future recommendations

The Food and Move project was a collaborative project with the students, staff and parents from four Warrnambool secondary colleges which focussed on promoting healthy eating and physical activity in secondary schools and built capacity for ongoing health promotion to address overweight/obesity.

The project aimed to:

1. Increase awareness amongst students, parents and staff of the links between regular physical activity and good nutrition to achieve optimal health.
2. Increase awareness amongst students, parents and staff of childhood/adolescent obesity and its implications for future health.
3. Improve the opportunities for students to access healthy food at their school canteen.
4. Improve the opportunities for students to access physical activity at recess and lunchtime.
5. Prepare a resource package of initiatives for use in secondary colleges to support the provision of opportunities for healthy eating and physical activity at Warrnambool secondary colleges.
6. Support the development of appropriate physical activity and nutrition curricula.