Time:June 1, 2018 at 9:00 am
1.Title：Endeavor for developing new approaches to evaluate materials performance in service
Reporter：Ben Jar, Ph.D., P.Eng. Professor，Department of Mechanical Engineering, University of Alberta, Canada.
Summary：Mechanical property is one of the most important pieces of information for materials characterization, especially to evaluate their suitability for load-carrying applications. Although an extensive variety of standard methods are now available for establishing the relationship between mechanical properties and material performance, a pretty wide gap still exists for applying mechanical properties measured from coupon specimens to prediction of in-service performance. The main objective of my research is to develop new test methods to close this gap and to shorten the time for material evaluation in load-carrying applications.
This presentation will give examples from our recent studies on the needs of new test methods to evaluate material performance. The presentation will introduce two approaches in which coupon test results are directly used to evaluate material performance in service, of which one is for polyethylene (PE) and the other steel. The former is used to make gas and water pipes and the latter railway network. Although both types of materials are now widely used in their respective applications, the presentation will show that there are still needs of new methods to characterize their mechanical properties, not only to meet the application requirements but also to satisfy the academic curiosity. The presentation will also give a brief history about how I became interested in these areas and how I set the research goals to maintain interests from industries. The presentation will conclude by summarizing what we have learned from the studies and pointing out the future work that will benefit from research collaboration.
Introduction:Fellow of the Canadian Society of Mechanical Engineers (CSME), winner of the G.H. Duggan Award, the highest academic honor of the Canadian Society of Mechanical Engineers. Published 120 SCI journal papers and 6 professional English books. He is the former graduate program director of the School of Mechanical Engineering at the University of Alberta.2.Title：Application of High Frequency Ultrasound in Dentistry
Reporter：Lawrence H Le, PhD, MBA, Professor, Medical Physics, Graduate Coordinator，Radiology and Diagnostic Imaging, University of Alberta, Canada.
Summary：Intraoral ultrasonography uses high-frequency mechanical waves to study dento-periodontium. Besides the advantages of portability and cost-effectiveness, ultrasound technique has no ionizing radiation. Previous studies employed a single transducer or an array of transducer elements, and focused on enamel thickness and distance measurement. This study used a phased array system with a 128-element array transducer to image dento-periodontal tissues. We studied two porcine lower incisors from a 6-month-old piglet using 20-MHz ultrasound. The high-resolution ultrasonographs clearly showed the cross-sectional morphological images of the hard and soft tissues. The investigation used an integration of waveform analysis, travel-time calculation, and wavefield simulation to reveal the nature of the ultrasound data, which makes the study novel. With the assistance of time-distance radio-frequency records, we robustly justified the enamel-dentin interface, dentin-pulp interface, and the cemento-enamel junction. The alveolar crest level, the location of cemento-enamel junction, and the thickness of alveolar crest were measured from the images and compared favorably with those from the cone beam computed tomography with less than 10% difference. This preliminary and fundamental study has reinforced the conclusions from previous studies, that ultrasonography has great potential to become a non-invasive diagnostic imaging tool for quantitative assessment of periodontal structures and better delivery of oral care.
Personal profile:Fellow of American Medical Physics Association and Canadian Medical Physics Association, editor and reviewer of 13 well-known academic journals including IEEE Access, Annals of Applied Acoustics, Medical Physics, Sensors, Ultrasonics, etc. Adjunct professor at Fudan University.
