Understanding the Behaviour of PET in Stretch Blow Moulding

This paper is concerned with understanding the behaviour of Polyethylene Terephthalate (PET) in the injection stretch blow moulding (ISBM) process where it is typically bi-axially stretched to form bottles for the packaging industry. Preforms which have been pre sprayed with a pattern and heated in an oil bath have been stretched and blown in free air using a lab scale ISBM machine whilst being monitored via high speed video. The images have subsequently been analysed using a digital image correlation system (VIC 3D). Results are presented showing the typical deformation modes and strain rates encountered in the ISBM process.

Modelling and Instrumentation of Stretch Blow Moulding

The injection stretch blow moulding process is used to manufacture PET containers used in the soft drinks and carbonated soft drinks industry. The process consists of a test tube like specimen known as a preform which is heated, stretch and blown into a mould to form the container. This research is focused on developing a validated simulation of the process thus enabling manufacturers to design their products in a virtual environment without the need to waste time, material and energy. The simulation has been developed using the commercial FEA package Abaqus and has been validated using state of the art data acquisition system consisting of measurements for preform temperature (inner and outer wall) using a device known as THERMOscan (Figure 1), stretch rod force and velocity, internal pressure and air temperature inside the preform using an instrumented stretch rod and the?exact?timing of when the preform touches the mould wall using contact sensors.? In addition, validation studies have also been performed by blowing a perform without a mould and using high sped imaging technology in cooperation with an advanced digital image correlation system (VIC 3D) to provided new quantitative information on the behaviour of PET during blowing.? The approach has resulted in a realistic simulation in terms of accurate input parameters, preform shape evolution and prediction of final properties.

Multi-centre research in Australia:analysis of a recent National Health and Medical Research Council-funded project

BACKGROUND AND OBJECTIVE: Human research ethics committees provide essential review of research projects to ensure the ethical conduct of human research. Several recent reports have highlighted a complex process for successful application for human research ethics committee approval, particularly for multi-centre studies. Limited resources are available for the execution of human clinical research in Australia and around the world.

METHODS: This report overviews the process of ethics approval for a National Health and Medical Research Council-funded multi-centre study in Australia, focussing on the time and resource implications of such applications in 2007 and 2008.

RESULTS: Applications were submitted to 16 hospital and two university human research ethics committees. The total time to gain final approval from each committee ranged between 13 and 77 days (median = 46 days); the entire process took 16 months to complete and the research officer's time was estimated to cost $A34 143.

CONCLUSIONS: Obstacles to timely human research ethics committee approval are reviewed, including recent, planned and potential initiatives that could improve the ethics approval of multi-centre research.

Aspirin and folic acid for the prevention of recurrent colorectal adenomas

BACKGROUND & AIMS: Although observational studies have found regular aspirin use to be associated with a reduced risk of colorectal neoplasia, results from randomized trials using aspirin have been inconsistent. Dietary folate intake also has been found to be associated with a reduced risk of colorectal neoplasms in observational studies.

METHODS: A multicenter, randomized, double-blind trial of aspirin (300 mg/day) and folate supplements (0.5 mg/day) to prevent colorectal adenoma recurrence was performed using a 2 x 2 factorial design. All patients had an adenoma (>/=0.5 cm) removed in the 6 months before recruitment and were followed-up at 4-month intervals with a second colonoscopy after approximately 3 years. The primary outcome measure was a colorectal adenoma diagnosed after baseline.

RESULTS: A total of 945 patients were recruited into the study, of whom 853 (90.3%) underwent a second colonoscopy. In total, 99 (22.8%) of 434 patients receiving aspirin had a recurrent adenoma compared with 121 (28.9%) of 419 patients receiving placebo (relative risk, 0.79; 95% confidence interval [CI], 0.63-0.99). A total of 104 patients developed an advanced colorectal adenoma; 41 (9.4%) of these were in the aspirin group and 63 (15.0%) were in the placebo group (relative risk, 0.63; 95% CI, 0.43-0.91). Folate supplementation was found to have no effect on adenoma recurrence (relative risk, 1.07; 95% CI, 0.85-1.34).

CONCLUSIONS: Aspirin (300 mg/day) but not folate (0.5 mg/day) use was found to reduce the risk of colorectal adenoma recurrence, with evidence that aspirin could have a significant role in preventing the development of advanced lesions.