Abstract
In recent years, there is a strong interest in ptychography, which computationally constructions a model of the sample from series of diffraction data collected from electron microscopes [1]. We have demonstrated a resolution of 0.67 Å or better using ptychography with a 20 keV electron beam operating in a transmission mode using a SEM with a cold emission gun and immersion lens.
We achieved this through combination of: adding a simple diffraction projector lens to our SEM; using an un-coated hybrid direct electron detector [3]; and incorporating correction of diffraction
projector distortions within a multi-slice ptychographic reconstruction process. Measurement and corrections of lens distortions is in general not trivial, so in our work we have simplified distortion evaluation using machine learning methods, as will be described. Also, using low energy scanning transmission electron diffraction in a SEM has provided us very valuable information for understanding the structure of novel polymer structures, as will be illustrated. These advances serve to widen access to, and hence help democratize, information that is currently only available from high-end TEM. At low bean energies interesting possibilities are presented with computationally assisted SEM, particularly with imaging thin, low atomic-number based samples, which present greater information at lower energies. This may in the longer-term assist in the structural determination of proteins with masses below about 100 kDa.
Speaker Bio
Arthur Blackburn is the Hitachi High-Tech Canada Research Chair, Co-Director of the Advanced Microscopy Facility and Assistant Professor in the Department of Physics and Astronomy at the
University of Victoria. Prior to joining the University of Victoria, he was a Senior Research Scientist in the Hitachi Cambridge Laboratory, embedded with the Cavendish Laboratory of the University of Cambridge. He progressed to this role after completing his PhD within the University of Cambridge, Department of Physics.
Abstract
Manipulating the structure and chemistry of grain boundaries and interphase interfaces in crystalline materials are crucial to obtain materials with desirable physical and functional properties. Although there are many experimental studies on grain boundary segregation in various alloys and ceramics, the study of the transformation from the initial solid solution structure at the atomic scale have not been explored. In this study, a novel bicrystal technique was developed to produce yttria stabilized zirconia (YSZ) bicrystal specimens without Y3+ segregation to the grain boundary. Scanning transmission electron microscopy (STEM) and energy dispersive X-ray spectroscopy (EDS) characterization confirmed that the specimen is indeed free of Y3+ segregation. To trigger grain boundary segregation, the specimen was annealed at various temperatures and the structure and chemistry were tracked by atomic resolution STEM imaging and EDS mapping. The fundamental understanding of the segregation sequence, as well as the conditions that can activate solute segregation are important for tailoring the properties and behaviour for the specific applications of YSZ, including solid electrolyte for solid oxide fuel cells (SOFCs) and cutting tools.
Speaker Bio
Jason Tam is currently a postdoctoral researcher at The University of Tokyo. He received his B.A.Sc. and Ph.D. from the Department of Materials Science and Engineering, University of Toronto. During his graduate study, he was also a visiting scholar at Hokkaido University and The University of Tokyo. Prior to his current position in Japan, he took on several roles at the University of Toronto as a postdoctoral researcher, undergraduate course instructor, and research scientist supporting the operations of the electron microscopy facility in OCCAM. His research interests include physical metallurgy, specifically interfaces of materials, electrochemical synthesis of nanostructured materials, and electron microscopy.
Speaker Bio
Dr. Fernando Morgan is the Technology Strategy Manager at AnoxKaldnes-Veolia Water Technologies. Fernando completed his MASc and PhD in the Department of Chemical Engineering and Applied Chemistry at the University of Toronto, working on the biofiltration of air emissions and biological wastewater treatment in the pulp and paper industry. He has over 20 years of environmental process engineering including a Post-doctoral fellow (Applied microbiology) at UGhent (Belgium) and Aalborg Univ. (Denmark). He has been at AnoxKaldnes since 2007 working on a variety of innovative biotechnologies for waste treatment and production of value-added products.
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Abstract
Polymer blends and polymer-based nanocomposites are multiphase materials that are present in many applications due to the interesting properties that they present. The challenge in their design relies on a proper control of their morphology, which, in turn controls their engineering properties. In this talk, it will be shown how rheology can be used as a tool to characterize and control the morphology of these materials. Some applications in the fields of energy and separation membranes will be discussed.
Speaker Bio
Nicole Raymonde Demarquette received her B.Eng. from the Institut Polytechnique de Grenoble, France, as well as, a Diplôme d’Études Approfondies in Chemical Engineering from the same institute. Then, she received a M.Sc. and a Ph.D. in Chemical Engineering from McGill University, Montreal, Canada. She also obtained a Livre-docência in Materials Engineering from the University of Sao Paulo, Brazil where she was a Professor between 1996 and 2012. In 2012, she returned to Canada and joined École de Technologie Supérieure in Montréal. She presently holds a Tier 1 Research Chair in Rheology to develop Novel Polymer Blends and Nanocomposites. She is the author or coauthor of more than 160 publications, several review papers and book chapters.
Durgesh Prasad Kavishvar
Doctor of Philosophy
Department of Chemical Engineering University of Toronto
Abstract
Yield stress is a characteristic stress depicting the flow behavior of many complex materials. When the applied shear stress is lower than yield stress, materials exhibit solid-like behavior, transitioning to liquid-like behavior for shear stress>yield stress. Conventional rheometers often struggle with sensitivity in measuring low yield stress, lack real-time measurement capabilities, and are prohibitively expensive. These limitations are particularly pronounced in biological materials such as blood and mucus, where variations in yield stress can signify underlying health conditions. For instance, yield stress of blood from patients with cerebrovascular and cardiovascular diseases, hypertension, sickle cell disease, among others, exceeds that of healthy blood. Similarly, yield stress of mucus from individuals battling conditions such as cystic fibrosis or asthma can be several orders of magnitude higher than that of healthy lung mucus. Also, yield stress measurements prove valuable for quality assessment in various industries such as oil & gas as well as food industry.
In this work, we investigate, through experiments, scaling analysis, and simulation, the yielding behavior of various complex materials in a Hele-Shaw microfluidic extensional flow device (MEFD). We propose the MEFD as a new microfluidic rheometer capable of measuring a low yield stress ranging from 5 mPa−5 Pa. The design of the MEFD is such that it enables a gradient in shear stress, shear stress, such that shear stress is lower near the center or stagnation point, and higher away from the stagnation point. For a yield stress fluid, we observe that, below a certain flow rate, shear stress exceeds yield stress only in the outer region, leading to stagnation or unyielding of the fluid in the inner region. Our simulation study also corroborates the experimental findings, demonstrating the existence of an unyielded region near the stagnation point of the extensional flow. We apply scaling analysis to deduce yield stress by measuring this size of the unyielded region at center. We validate the scaling relationship using Carbopol solutions of various concentrations (0.015 to 0.3%), measuring yield stress as low as ~10 mPa to ~1 Pa, and comparing these measurements with a standard rheometer.
Furthermore, we showcase the applicability of our rheometer by measuring yield stress of human blood samples ranging between 30−80 mPa for a range of hematocrits as well as yield stress of porcine gastric mucins (20%) of 0.7 Pa. We also demonstrate measurements of yield stress of clay suspensions (2 to 6%), useful in oil & gas applications. We also show a proof of concept for food industry by measuring yield stress of a lactic drink of roughly 7 mPa. Our microfluidic rheometer offers several other advantages, including real-time measurement capability (with measurement time as short as 4 s), low volume requirement (<1 ml), ease of cleaning and reuse, and cost-effectiveness. Therefore, it attracts diverse applications in clinical research, particularly in disease detection, as well as in industries such as food and oil & gas for quality assessment.
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A U of T Engineering startup co-founded by Adnan Sharif (ChemE MEng student) has its roots in an experience that is all too common for many of us — he kept forgetting to water his plants.
“I was working in a plant immunity biology lab, so if I didn’t water them, I’d have no plants to do experiments with,” says Sharif.
At the time, Sharif was a U of T undergraduate student working with Professor Keiko Yoshioka in the Department of Cell & Systems Biology. He has since graduated and is now pursuing an MEng in the Department of Chemical Engineering & Applied Chemistry.
“My dad is a mechanical engineering professor at a university in Japan, and he knows a lot about manufacturing materials with porous, three-dimensional structures. So that’s how I got the idea to make my own 3D printed soil construct, which could retain water for a week or more. That way, I wouldn’t have to go into the lab and water the plants so often.”
Today that product is called SmartSoil, and it’s one of the key innovations at the heart of Lyrata, a startup that is producing edible crops for caterers and high-end restaurants across the Greater Toronto Area.
Support from the U of T Engineering community has been key to Lyrata’s success. For example, it was a U of T Engineering alumni connection that recently led to Lyrata launching an installation at Casa Loma, a historic museum and landmark in midtown Toronto.
Abstract
Algae have long been promoted as alternative hosts for sustainable biotechnology concepts owing to their capacity for light-driven circular reuse of waste streams as inputs and the production of biomass rich in valuable natural products. The emerging capacity to tailor algal cell metabolism through genetic engineering for the sustainable production of desired biochemicals holds the promise of co-product generation from algal bioprocesses to multi-valorize waste inputs. Microalgal metabolic engineering has emerged in recent years due to the intersection of reliable DNA synthesis and improved understanding of transgene expression limitations, especially in the model green microalga Chlamydomonas reinhardtii. This alga has been a powerful workhorse for demonstrating the possibilities of eukaryotic algal metabolic engineering, especially for isoprenoid targets. Other eukaryotic microalgae are also coming to light as potential hosts for synthetic biology mediated genetic engineering concepts. The model red microalga Cyanidioschyzon merolae 10D is a polyextremophilic member of the Cyanidiophyceae that grows at pH 0.5-2 and 42-50 ˚C, lacks a cell wall, and can be cultured with low risk of contamination. C. merolae exhibits favorable genetic features such as targeted transgene integration by homologous recombination into its small nuclear genome (16 Mb) and few introns. We have recently developed a new, completely synthetic, molecular toolkit for transformation of the nuclear genome of this alga. In this presentation I will highlight advances in its metabolic engineering for heterologous generation of several products in addition to its cultivation outdoors on the mid Red Sea coast in 1000 L tubular photobioreactors. I will also describe our engineering strategies to expand the capacity of C. reinhardtii and C. merolae as green cell factories, highlight new developments in bio-process designs, the value of metabolic engineering for fundamental understanding of algal metabolism, and discuss the value of regional considerations for algal biotechnology in the Middle East.
Speaker Bio
Dr. Kyle J. Lauersen is an Assistant Professor at King Abdullah University of Science and Technology (KAUST) in Thuwal, Saudi Arabia. His group is named Sustainable & Synthetic Biotechnology with their main research focussed on engineering algae to be green cell factories. Kyle did his Doctorate of Natural Sciences at Bielefeld University in Germany, and his master’s as well as undergrad at Queen’s University in Kingston, Ontario, Canada.
Abstract
System Mapping is a set of structured visualization techniques that help groups and individuals to look at the relationships and underlying assumptions of complex systems. Systems Mapping can be useful for researchers as they seek to understand the social, environmental and economic context in which their research sits – critical information when trying to bring new ideas to market or to assess the sustainability of a new technology. This interactive seminar will introduce systems mapping, share some real world examples where mapping has been used, and invite participants to generate and share simple maps related to their own research.
Speaker Bio
Professor Emily Moore is the Director of the Troost Institute for Leadership Education in Engineering (ILead) at the University of Toronto where she researches how engineers lead as they deliver new technologies to market. Emily holds a bachelor’s in engineering chemistry (Queen’s) and a doctorate in physical chemistry (Oxford) and is a licensed professional engineer. Emily launched her career at the Xerox Research Center of Canada (XRCC), then joined engineering consulting firm Hatch where she led the water business and technology development portfolio. Emily holds 21 patents and is a Fellow of the Canadian Academy of Engineering. Emily’s leadership in industry was recognized with the 2016 Kalev Pugi Award (SCI Canada) and she was named one of 100 Global Inspirational Women in Mining by Women in Mining UK. Emily serves as a board member of Chemtrade Logistics, International Petroleum Corporation, and the Canadian Mining Innovation Council.
Abstract
Microfluidics exploits fluids and their physical and chemical properties at the microscale, enabling miniaturized platforms that offer lower cost, faster pace, higher performance, and increased portability than their macroscale counterparts. This talk will briefly discuss three research themes including droplet microfluidics, microwave sensing and soft robotic wearable systems.
- Two-phase droplet microfluidics employs monodispersed water-oil emulsions as mobilized test tubes to perform high throughput analysis (HTA). Despite numerous novel technologies reported, the adoption of droplet microfluidics as an HTA tool by non-microfluidics experts has not been seen. Modular-based droplet microfluidics, enabling easy assembly of application-specific systems, presents tremendous potential to break this barrier. This talk will introduce our work towards this goal including, a suite of physical models that can serve as design tools for passive-based droplet modules such as droplet generators, mergers, sorters and heaters, and a unique active droplet microfluidics method that relies on visual feedback of droplet position to actuate a pressure source to actively control individual droplets realizing functional modules.
- Simultaneous sensing and heating of individual droplets are critical but very challenging. Microwave resonators present tremendous potential to meet this need which will be the second part of this talk. Microwave sensing finds various applications beyond droplet microfluidics. Its applications for the detection of virus such as SARS-CoV-2 and E. coli as well as metal ions will be discussed.
- Soft robotic wearable systems offer hope to improve the quality of life for those in need because of their compliance nature. Most existing systems are expensive, power intensive and tethered to external power sources, limiting user mobility. Microfluidics enables miniaturization of the system including its front end (e.g. wearable sleeves) and back end (control unit), translating to low cost, tetherless and energy-efficient operation. This talk will present wearable sleeves for treating lymphedema, arthritis, and pressure ulcers due to the ill fit of prosthetic sockets.
Speaker Bio
Dr. Ren received her PhD in Mechanical Engineering from the University of Toronto and her master’s and bachelor’s degrees in Mechanical Engineering from Harbin Institute of Technology. She is currently a Professor of Mechanical and Mechatronics Engineering at the University of Waterloo (UW) and holds a Tier I Canada Research Chair (CRC) in Microfluidic Technologies. She is directing Waterloo Microfluidics Laboratory focusing on advancing fundamental knowledge of microfluidics and developing technologies that are impactful on a wide range of applications such as life science research, protein fractionation towards drug screening, water quality sensing and assistive technology for well-being. Besides the CRC, Dr. Ren has also received several awards from the engineering and research community, including: election as a Member of Canadian Institute of Engineering in 2024, election as a Member of Canadian Academy of Engineering in 2023, recognition as one of Canada’s 100 Most Powerful Women in 2021, election as a Member of the College of New Scholars, Scientists and Artists of Royal Society of Canada in 2018, being recognized as one of 20 leading female innovators in Women of Innovation (Dr. Ren is a co-founder of four start-up companies) in 2017.
Abstract
The concept of oxy-fuel combustion involves using O2 separated from air to burn a fuel to generate a CO2 rich stream that can then be sequestered. However, if only O2 is fed into the boiler, the combustion temperature will be too high. In practice, flue gas would need to be cooled to condense out water and then a part of the CO2 rich flue gas is recycled and mixed with the O2 as the feed oxidant to the combustion system. The remaining CO2 rich gas (>90% CO2) can be compressed and sequestered or further purified and used as new uses for CO2 are developed.
There are three different combustion systems found in pulp mills:
- Kraft recovery boiler for burning black liquor
- Lime kiln for driving CO2 from CaCO3 to generate CaO
- Biomass boiler where bark and reject wood from pulping are burned
In this presentation I will talk about the early research in oxyfuel combustion in kraft recovery boilers and lime kilns and some of the process and process chemistry implications of transitioning from traditional combustion with air to oxyfuel combustion.
Speaker Bio
Nikolai De Martini is an Associate Professor of Chemical Engineering and Director of the Pulp and Paper Centre at the University of Toronto. He joined the faculty in 2017. Prof. De Martini earned a PhD in Chemical Engineering for work on nitrogen and sulfur chemistry in kraft recovery boilers at Åbo Akademi University in Turku, Finland. He currently leads the industrial consortium Effective Energy and Chemical Recovery in Pulp and Paper Mills which is supported by pulp and paper companies in Canada, the United States, Brazil, Chile, Finland and Sweden. He is also a New York Times Bestselling Author for his book, “Does Anybody Proofread”.