​Bio: Todd Arbogast earned his Ph.D. in mathematics from the University of Chicago. He is professor of mathematics, chair of the Computational Sciences, Engineering and Mathematics Graduate Studies Committee, and a founding member and associate director of the ICES Center for Subsurface Modeling. He is the faculty co-adviser of the university’s student chapter of the Society for Industrial and Applied Mathematics. He is the current holder of the W. A. "Tex" Moncrief, Jr. Simulation-Based Engineering and Sciences Professorship I.  His research contributes to the development and analysis of numerical algorithms for the approximation of partial differential systems, high performance and parallel scientific computation, and multi-scale mathematical modeling, as applied to fluid flow and transport in geologic porous media. Important applications include petroleum production, groundwater contamination, carbon sequestration, and mantle dynamics.

Arbogast’s research includes Eulerian-Lagrangian schemes for transport, mixed finite element and mortar techniques for flow, homogenization and modeling of flow through multi-scale fractured and vuggy geologic media, simulation of partially molten materials, and variational multi-scale methods for heterogeneous media.  

Arbogast has authored more than 70 scientific and technical publications, and serves on the editorial boards of three scientific journals and technical series. He is the recipient of an ICES Distinguished Research Award, a Moncrief Grand Challenge Faculty Award, and a Frank Gerth III Faculty Fellowship.

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• CONTACTProf. Hussein Hoteit

​ABSTRACT: Optoelectronic devices such as light-emitting diodes (LEDs) for general illumination have nowadays a tremendous impact in human life, residential and industrial sectors. The global and societal technology development, including those related to energy saving, are promoting the solid state lighting market towards a strong evolution. After their success as base materials for blue LEDs (Professors Isamu Akasaki, Hiroshi Amano and Shuji Nakamura - Nobel Prize in Physics of 2014), LEDs based on III-N semiconductors are capable of light emission from the ultraviolet to the red, thanks to the possibility of InGaN and AlGaN bandgap engineering. In fact, as the indium content in InGaN ternary alloys increases, the emission wavelength can be tuned from UV-blue to green to red, but also their emission efficiency decreases due to the induced crystal quality degradation. Therefore, intense research activity is dedicated to achieve efficient green/red emitters for the development of powerful monolithic white LEDs and full-color displays. This seminar will bring possible solutions/approaches to surpass these issues, involving controlled doping strategies and post-growth treatments in III-N nanostructures.


BIOGRAPHY: Nabiha Ben Sedrine (NBS) is a Researcher at the Physics Department of the University of Aveiro and Institute of Nanostructures, Nanomodelling and Nanofabrication (I3N). Her research interests are devoted to study key issues in semiconductor (III-V, III-N) and oxide (ex. Ga₂O₃) nanosctructures, by probing their optical properties and correlating with their structural, electrical and magnetic properties for optoelectronic, spintronic and quantum technology applications. NBS has a recognized expertise in optical characterization of materials using different spectroscopic techniques, such as: spectroscopic ellipsometry (NIR-Vis UV, IR, far-IR ranges, magneto-optic ellipsometry), absorption, reflectance, photoluminescence excitation, photoluminescence in steady and transient states, FTIR, Raman spectroscopy. 

NBS completed her PhD degree in Physics 2009 at Faculté des Sciences de Tunis (FST) - University of Tunis El Manar and Centre de Recherches et des Technologies de l'Energie (CRTEn) (Tunis, Tunisia) in collaboration with Laboratoire de Photonique et de Nanostructures (LPN-CNRS) (Paris, France). Since then, she pursued post-doctoral positions in Portugal (Instituto Superior Técnico-Lisbon) and Sweden (Linköping University, Linköping), with several research stays in France (LPN-CNRS Paris, Université de Franche-Comté Besançon), USA (University of Nebraska-Lincoln, Nebraska) and Portugal (International Iberian Nanotechnology Laboratory INL, Braga). 

NBS was member of the Director Committee (mandate 2010-2012) in Société Tunisienne de Physique (STP) and now active member in several scientific societies: STP, Sociedade Portuguesa de Física (SFP), Associação Nacional de Investigadores em Ciencia e Tecnologia (ANICT), Swedish Institute (SI) Alumni, LiU-Junior Faculty. 

ORCID: https://orcid.org/0000-0002-2255-3453 (Current/Past Projects, Publications, Popular Science Dissemination) 
Google scholar: http://scholar.google.fr/citations?user=BqXUSLUAAAAJ&hl=fr (full list of Publications and Conferences)

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• CONTACTMazen E. Mero

​ABSTRACT: Transmission electron microscopy (TEM) is an important tool for the characterization of materials as it can provide a clear understanding of the relationship between structure, properties and composition of nanomaterials. For this, the in-situ TEM analysis is performed and requires specially manufactured sample holders. In particular, those designed to carry out electrical biasing can be used to understand not just the I-V characteristics but also the failure mechanism, structure-property relationships, Joule heating dynamics, electromigration, field emission properties, etc. at the nanoscale.

The platforms holding the sample in most modern in-situ TEM holders rely on an insulating ceramic membrane which needs to be (almost) transparent to the imaging electron beam. Electrodes are defined through lithography and patterned on this membrane. Unfortunately, the presence of this membranes introduces several limitations such as electrostatic charging, reduction of image contrast and poor mechanical stability. To circumvent this issue it is necessary to fabricate a novel type of sample platform which does not rely on the presence of a membrane. 

In this work, novel membraneless sample-holding platforms were designed and manufactured using advanced microfabrication methods and tools. Besides fitting into an array of analytical tools, the novel platforms (or “chips”) can be subjected to thermal and/or chemical processing without compromising their function or structure. 

To test these, the electrical response of one-, two- and zero-dimensional nanoparticles were studied. Firstly, we investigated current-induced modifications in silver nanowires and expandable graphite flakes and studied various phenomenon involved. Along with these, corresponding ex-situ studies were also performed. Next, graphene oxide was explored as an alternative support platform for in-situ TEM. We successfully achieved temperature as high as 2000^o C by Joule heating of graphene oxide. Furthermore, this graphene oxide platform was used as a heater and chemical processing substrate for investigating thermal stability and synthesis of inorganic nanoparticles, respectively.

​Abstract:  Supramolecular self-assembly of a certain number of designer organic/inorganic building blocks by directional interactions such as metal coordination is the basis of elaborate molecular systems. Most molecular architectures are purpose-designed in light of the size, shape, and surface natures of building blocks as well as chemical environments. On the other hand, we have occasionally come across unexpected structures and functions as a result of more complicated self-assembly processes than expected, which have often opened a new frontier in chemistry. The present lecture will focus on complexity in coordination-driven self-assembly by taking some of our recent examples of artificial metallo-DNAs,1-4 metallo-containers,5,6 molecular gearing systems,7-9 and metal macrocycle framework (MMF).10-12

References:
1.    K. Tanaka, A. Tengeiji, T. Kato, N. Toyama, M. Shionoya, Science 2003, 299, 1212.
2.    K. Tanaka, G. Clever, Y. Takezawa, Y. Yamada, C. Kaul, M. Shionoya, T. Carell, Nat. Nanotechnol. 2006, 1, 190.
3.    Y. Takezawa, J. Müller, M. Shionoya, Chem. Lett. (Highlight Review) 2017, 46, 622.
4.    Y. Takezawa, T. Nakama, M. Shionoya, J. Am. Chem. Soc. 2019, in press.
5.    L.-J. Chen, H.-B. Yang, and M. Shionoya, Chem. Soc. Rev. 2017, 46, 2555.
6.    H. Ube, K. Endo, H. Sato, M. Shionoya, J. Am. Chem. Soc. 2019, 141, 10384.
7.    K. Sanada, H. Ube, M. Shionoya, J. Am. Chem. Soc. 2016, 138, 2945.
8.    H. Ube, Y. Yasuda, H. Sato, M. Shionoya, Nat. Commun. 2017, 8, 14296.
9.    H. Ube, R. Yamada, J. Ishida, H. Sato, M. Shiro, M. Shionoya, J. Am. Chem. Soc. 2017, 139, 16470.
10.    S. Tashiro, R. Kubota, M. Shionoya, J. Am. Chem. Soc. 2012, 134, 2461.
11.    R. Kubota, S. Tashiro, M. Shiro, M. Shionoya, Nat. Chem. 2014, 6, 913.
12.    H. Yonezawa, S. Tashiro, T. Shiraogawa, M. Ehara, R. Shimada, T. Ozawa, M. Shionoya, J. Am. Chem. Soc. 2018, 140, 16610.

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• CONTACTLinda J. Sapolu
• EMAILLinda.Sapolu@kaust.edu.sa

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• CONTACTEmmanuelle Sougrat