Speakers

Speaker I

Takao Mori, Research Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science (NIMS), Japan

Biography: Takao Mori received his PhD at the University of Tokyo, Dept. of Physics. He is a Field Director at the National Institute for Materials Science (NIMS) in Japan. He is also a Professor of the University of Tsukuba, Graduate School, and elected Board Member of the International Thermoelectric Society (ITS), elected President of ITS from July 2023. Mori’s research interests are, broadly speaking, to find ways to control structures and properties of inorganic materials. He is especially involved now in development of thermoelectric materials and multidisciplinary enhancement principles, such as utilizing magnetism, in order to find new routes to achieve high control over band structures and electrical and thermal transport. Mori is a Senior Editor of Materials Today Physics and Associate Editor of Materials for Renewable and Sustainable Energy, an Editorial or Advisory Board Member of Journal of Solid State Chemistry, Advances in Applied Ceramics, Journal of Materiomics, Joule. He is a Program Manager of Japan Science and Technology Agency (JST) Mirai Large-scale Program. Mori has published over 350 journal papers, 25 book chapters, and 35 patents.

Speech Title: Development of Enhanced Thermoelectric Materials & Devices
Development of thermoelectric (TE) materials is important, as in addition to energy saving via waste heat power generation, they can also serve as dynamic power sources for innumerable IoT sensors and devices. To achieve enhanced thermoelectric performance, it is necessary to find ways to overcome the traditional tradeoffs between the key properties, namely, between the Seebeck coefficient S and electrical conductivity σ, and between the electrical and thermal conductivity σ. Namely, find ways to enhance S, and also selectively lower K.
For the latter, nanostructuring which can utilize the difference in the scattering mean free paths of charge carriers and phonons, so as to degrade σ as little as possible while reducing K. Modifying; i.e. softening, the bonding in materials through various means such as partial occupancy, selective doping, multiple anion, etc. has been shown to be very powerful. A strong effect of lowering the phonon velocity via interstitial doping also led to development of the first materials able to challenge the more than half century champion bismuth telluride Bi₂Te₃. TE conversion efficiency of ~12% was recently demonstrated for a single cell device. In order to overcome the first tradeoff, various principles have been found to enhance the Seebeck coefficient and overall power factor (PF). Namely, band engineering and especially novelly to utilize magnetism to enhance the S. Coupling of electrical carriers with magnetic moments, can lead to magnon drag which was known from long ago in Fe, etc. to lead to increase in S at low temperatures. Recent advancement is that magnon drag was found to actually able to lead to high performance, i.e. high PF at higher temperatures, namely for e.g. CuFeS₂ chalcopyrite. The full Heusler compound Fe₂VAl has been shown to be a particularly rich field to utilize these principles, with bulk materials shown to achieve PF several factors larger than the best Bi₂Te₃ materials. Band engineering doping to control the energy gap and recently, utilization of Anderson localization states in Fe₂VAl-based compounds was shown for both ways to attain PF>10 mW/m/K². Spin fluctuation was also shown to enhance the Seebeck coefficient in Fe₂VAl. Recently, magnon drag was also proposed as an origin of the huge power factor in metastable Fe₂VAl-based thin films. I would also like to present the various forms of TE power generation (TEG) devices which have been proposed for applications, such as various bulk modules, thin film devices, flexible TEGs, etc. Support from JST Mirai Large-scale Program is acknowledged.

Speaker II

Prof. Zhongwei Guan is Executive Director of Advanced Materials Research Centre of Technology Innovation Institute, Abu Dhabi

Professor Zhongwei Guan is Executive Director of Advanced Materials Research Centre of Technology Innovation Institute in Abu Dhabi. He received his first degree on Solid Mechanics in Sichuan University China in 1982 and was awarded PhD on Structural Behaviour of Polymeric Pipelining in University of Bradford UK in 1993. He was Reader in Lightweight Composite Materials and Structures at the University of Liverpool. He has published more than 170 SCI papers in refereed leading international journals on lightweight composite structures subjected to extreme loading conditions such as projectile impact and blast, covering fibre metal laminates, PVC foam-based sandwiches and SLM lattice structures, corrugated sandwiches, timber structures, high temperature TP prepreg, etc., with a h-index of 41 in Google Scholar and citation more than 5400. He was Chairman of the 5th International Conference on Computational Methods held in Cambridge in 2014. He is a member of editorial board of International Journal of Impact Engineering, Applied Composite Materials and Advanced Materials Letter. He also serves as a scientific committee member of more than 20 international conferences and has given more than 20 keynotes, thematic and plenary speeches.

Speech Title: A Novel Technology for the Design and Manufacture of Thermoplastic Composites based on an Aqueous Powder Impregnation
This study investigates a novel thermoplastic prepreg rig and method of manufacturing prepregs using aqueous wet powder impregnation, including a fibre spreading assembly. The spread of S2-glass fibre was measured after the fibre bundle was dipped in a resin bath containing polyarylether ketone (PAEK) powder slurry and subsequently passed through the spreading process. The effects of motion frequency, amplitude and fixed or rotating rollers on the degree of fibre spreading were studied. A frequency of 5 Hz along with 6 mm of motion amplitude was found as one ideal combination in providing efficient and effective fibre spreading. Observations indicate that the width of the as received S2-glass fibre tow could be increased up to 7 times when rotating rollers were used, and up to 10 times when fixed rollers were utilised. The compact and easily maintained prepreg rig developed is suitable for rapid prepreg manufacturing in laboratory-scale research. The rig could be used with a wide range of thermoplastic powders and reinforcing fibres. Tests were conducted to study various settings and parameters, including the polymer–carrier ratio, winding speed and fibre tension. The study examined the effectiveness of the liquid carrier in suspending the polymer powder and tested the consistency of the rig in resin pick-up. The findings indicate that a winding speed of 6.7 to 9.0 rpm with a low fibre tension is ideal for producing S2-glass/PAEK prepregs. The amount of polymer pick-up by the fibre tow remained constant throughout the winding for 10, 20, and 30 wt% slurries. However, higher wt% slurry settings resulted in resin agglomeration on the rollers, causing significant fibre breakage.