Prof. Dr. Osamu TABATA, IEEE Fellow, Kyoto University of Advanced Science, Japan
Speech Title: Top-down meets bottom-up: Way to explore the plentiful room at the bottom
Abstract: In 1982 two papers in particular were published. One is recognized as the bible of Silicon micromachining, which is a typical top-down approach to miniaturization, and the other is known as the origin of DNA nanotechnology, which is a typical bottom-up approach to realizing nanoscale objects. Almost 40 years later the former is still the key to MEMS and the latter is the key to molecular machines. Both of these are recognized as powerful technologies and yet there remains a significant gap between them.
In this talk I begin by introducing the historical aspects of these two approaches to exploring the world at micro and nano scales. I then survey the current status of MEMS and DNA nanotechnology before discussing one challenging goal that remains to be addressed.
Biography: Osamu Tabata received his M.S. and Ph.D. degrees from Nagoya Institute of Technology, Japan, in 1981 and 1993, respectively. In 1981, he joined the Toyota Central Research and Development Laboratories, Inc., Japan. In 1996, he joined the Department of Mechanical Engineering, Ritsumeikan University, Japan. In 2003, he moved to the Department of Mechanical Engineering, Kyoto University, Japan. Since April 2005, he has been a Professor at the Department of Micro Engineering, Kyoto University. From October 2019, he moved to Kyoto University of Advanced Science as a founding Dean of Engineering School. He is currently engaged in research on micro/nano processes, MEMS, DNA nanotechnology.
Prof. Henry Hu, University of Windsor, Canada
Speech Title: Mg-based Alloys for Biomedical Applications: Properties and Microstructure
Abstract: Mg-Zn alloys have been demonstrated to be a good candidate for biodegradable applications. In the present work, Zinc (Zn) addition varying from 1.0 up to 10.0 wt. % was introduced into liquid magnesium. The alloyed liquid was squeeze cast under an applied pressure of 90 MPa. The results of mechanical testing on the squeeze cast Mg-Zn alloys shows that Zn is an effective additive for enhancing their mechanical properties, specifically, tensile and yield strengths at room temperature, but reducing the elongation. While the Zn addition rises from 1.0 to 10.0 wt.%, the ultimate tensile and yield strengths increases to 181.0 MPa and 105.0 MPa from 140.7 MPa and 39.3 MPa, while the elongation-to-failure (ef) decreases to 3.7% from 6.2%, respectively. The reveal of the as-cast grain structure by an optical microscope (OM) indicates that the high Zn content reduces grain sizes considerably. The microstructures analyzed by a scanning electron microscope (SEM) with the energy dispersive spectroscopy (EDS) show that the secondary MgZn phase forms once Zn is introduced in sufficient amount. The grain refinement and the massive presence of the secondary MgZn phase at the boundaries of the refined grains should be responsible to the enhancement of the strengths and the reduction in the elongation. The developed pressurized casting without employing secondary manufacturing processes such as extrusion or heat treatment exhibits its advantages to enhance the mechanical properties of the Mg alloys with high Zn content over conventional fabrication processes, since high Zn-containing Mg alloys have a long freezing range and tend to form microshrinkage porosity.
Biography: Dr. Henry Hu is a tenured full Professor at Department of Mechanical, Automotive & Materials Engineering, University of Windsor. He was a senior research engineer at Ryobi Die Casting (USA), and a Chief Metallurgist at Meridian Technologies, and a Research Scientist at Institute of Magnesium Technology. He received degrees from University of Toronto (Ph.D., 1996), University of Windsor (M.A.Sc., 1991), and Shanghai University of Technology (B.A.Sc., 1985). He was a NSERC Industrial Research Fellow (1995-1997). His publications (over 150 papers) are in the area of magnesium alloys, composites, metal casting, computer modelling, and physical metallurgy. He was a Key Reader of the Board of Review of Metallurgical and Materials Transactions, a Committee Member of the Grant Evaluation Group for Natural Sciences and Engineering Research Council of Canada, National Science Foundation (USA) and Canadian Metallurgical Quarterly. He has served as a member or chairman of various committees for CIM-METSOC, AFS, and USCAR. Prof. Hu’s current research is on materials processing and evaluation of light alloys and composites. His recent fundamental research is focussed on transport phenomena and mechanisms of solidification, phase transformation and dissolution kinetics. His applied research has included development of magnesium automotive applications, cost-effective casting processes for novel composites, and control systems for casting processes. His work on light alloys and composites has attracted the attention of several automotive companies.
Prof. Zengtao Chen, ASME Fellow, University of Alberta, Canada
Speech Title: Thermomechanical Analysis of Cracked Structures Using Non-Fourier, Non-Local Theories
Abstract: Fracture analysis of cracked structures under thermomechanical loading is of great interest in design and manufacturing of advanced thermal structures. In particular, structures of heterogeneous microstructures show non-Fourier heat conduction where thermal response shows a time delay with respect to the disturbance, and nonlocal mechanical behavior where the stress response relies on the intrinsic length scale of the material. Non-Fourier heat conduction has revealed dynamic overshooting of thermal response, which is essential to reliable design of a thermal barrier, while the non-local stress analysis allows removal of singular stress field around a crack tip. In the present talk, some recent progress in thermal stress analysis of cracked advanced composite materials are reviewed to illustrate the unique merit of non-Fourier heat conduction and nonlocal theory in analyzing the dynamic thermomechanical response.
Biography: Dr. Zengtao Chen joined the Department of Mechanical Engineering at University of Alberta as a Professor in August 2014. He has been a faculty member with the Department of Mechanical Engineering of University of New Brunswick for ten years prior to the current position with UofA. His research areas include Mechanics of Materials, Materials Modelling, and Damage and Fracture Mechanics. His recent work includes multiscale modelling of deformation and damage evolution in aluminum and steel alloys, advanced thermal stress analysis of smart materials and structures, nanostructures, and composite structures. He is a Fellow of ASME.