Seminar – Shaoyi Jiang
Shaoyi Jiang, Ph.D.
Boeing-Roundhill Professor of Engineering
Department of Chemical Engineering
University of Washington, Seattle
Molecular Understanding, Design and Development of Ultra Low Fouling Zitterionic Materials
An important challenge in many applications, ranging from medical devices to ship hulls, is the prevention of nonspecific protein adsorption on surfaces. To address this challenge, our goals are twofold. First, we strive to provide a fundamental understanding of nonfouling mechanisms at the molecular level using an integrated experimental and simulation approach. Second, we aim to develop biocompatible and environmentally benign ultra low fouling materials based on the molecular principles we have learned. As a result, we have demonstrated that zwitterionic and mixed charge materials and surfaces are highly resistant to nonspecific protein adsorption, cell adhesion and bacteria adhesion/biofilm formation from complex media. Both simulation and experimental results show that the strong hydration of zwitterionic materials is responsible for their excellent nonfouling properties (JACS 2005 and Advanced Materials 2015). Recent results show that zwitterionic materials induce no capsule formation upon implantation (Nature Biotechnology 2013) and no immunological response in blood circulation (PNAS 2015) and are able to preserve protein (Nature Chemistry 2012) and cell (Angewandte Chemie 2014) bioactivity. At present, zwitterionic materials, as alternatives to poly(ethylene glycol) (PEG)-based materials, have been applied to a number of applications, including medical devices, drug delivery carriers, antimicrobial coatings, and marine coatings.
Professor Jiang received his Ph.D. degree in chemical engineering from Cornell University in 1993 under Prof. Keith Gubbins. He was a postdoctoral fellow at UC Berkeley between 1993 and 1994 with Prof. Kenneth S. Pitzer and a research fellow at Caltech between 1994 and 1996 with Prof. William A. Goddard, III both in chemistry. He is currently the Boeing-Roundhill Professor of Engineering in the Department of Chemical Engineering at the University of Washington, Seattle. He was a visiting professor in the Department of Chemical Engineering at MIT with Prof. Robert Langer in 2007. He is a senior editor for Langmuir, a fellow of the American Institute of Chemical Engineers (AIChE), and a fellow of the American Institute for Medical and Biological Engineering (AIMBE). His research focuses on the molecular understanding, design and development of zwitterionic-based functional materials for biomedical and engineering applications.
Seminar – Richard Grenville
Richard K. Grenville
Director of Mixing Technology
Philadelphia Mixing Solutions Ltd., Palmyra, PA
Characterizing Impeller Performance in Stirred Tanks with Examples of Process Results
Impellers in stirred vessels are often described in terms such as high flow, high efficiency, high shear etc. These terms are qualitative and are not helpful when carrying out an agitator design / sizing calculation. The impellers are essentially pumps, they are machines that move fluid inside the vessel, and their performance characteristics can be defined in the same way as a pump; in terms of their power input, the flow and head generated and their efficiency. Impellers are also required to generate shear, either to disperse a second liquid, gas or solids phase in order to generate surface area for mass transfer or to promote coagulation / flocculation of fine particles suspended in the liquid phase.
The region of highest shear in a stirred tank is found in the trailing vortex at the tip of the impeller blades. The properties of the vortex must be taken into account in order to correctly calculate a local shear rate. In this presentation a method for quantifying the flow and shear characteristics of impellers will be presented demonstrating how this method may be applied to shear driven processes. The calculation method will be verified by comparing with results from droplet break-up and flocculation experiments.
The main conclusion of this work is that the Rushton turbine, traditionally considered “high shear”, actually generates larger droplets and flocs than a Hydrofoil, traditionally considered to be “low shear” at the same power input. Understanding this is important when selecting the appropriate impellers for processes where high or low-shear mixing are requirements.
Examples of processes that rely on flow, such as blending of tank contents, and shear, such as dispersion of immiscible liquids and flocculation of fine particles, will be used to demonstrate the application of this characterization approach.
Finally, the use of the word “shear” in the context of turbulent mixing will be discussed. While it is commonly used to convey the general idea of an impeller’s ability to reduce the size of a second phase, increasing interfacial area, it is not the best mechanistic description of the process which is driven by the local energy dissipation rate within the impeller’s trailing vortices.
Richard Grenville is Director of Mixing Technology at Philadelphia Mixing Solutions and has over 30 years of experience in the field of mixing.
He studied Chemical Engineering at the University of Nottingham in the UK, graduating in 1983, and started work as an Applications Engineer for Chemineer Ltd. sizing agitators and static mixers in response to customers’ inquiries.
After a brief period working as a Process Engineer at Unilever Research he went to work at the Fluid Mixing Processes consortium, which is managed by the British Hydromechanics Research Group, as a Project Engineer. His main area of research was mixing of non-Newtonian fluids. He also registered as a graduate student at Cranfield Institute of Technology and received his PhD in 1992.
In 1991 Richard joined DuPont as a mixing consultant in the Engineering department and worked on a wide variety of projects to manufacture, among others, fluorochemicals and polymers, various agricultural chemicals, water borne paint and fermentations. The last major project he worked on before leaving DuPont was the design of agitators for the Cellulosic Ethanol plant currently being commissioned in Nevada, IA.
In 2013 Richard joined Philadelphia Mixing Solutions as Director of Mixing Technology where he is responsible for developing solutions for customers’ mixing problems which may include lab-scale testing and scale-up. He regularly gives seminars for customers and AIChE student and local chapters.
Richard co-teaches courses on mixing at Rowan University in New Jersey and at the University of Delaware, is a Senior Member of the American Institute of Chemical Engineers, a Chartered Engineer and a Fellow of the Institution of Chemical Engineers. He is currently the president of the North American Mixing Forum.
Seminar – Charles Haynes
CBE – Fabio Ribeiro
Seminar – Huimin Zhao
Lowrie Lecture I: Eric Kaler
Seminar – Andrew Zydney
Andrew L. Zydney
The Pennsylvania State University
Purification of DNA for Gene Therapy and Vaccines – New Opportunities for Membrane Technology
There is growing interest in using DNA for gene therapy and DNA-based vaccines. Existing methods for DNA purification are inadequate for large-scale commercial production. This talk examines the possibility of using membrane ultrafiltration for the purification of supercoiled plasmid DNA. DNA transmission during ultrafiltration is a strong function of filtrate flux due to flow-induced elongation of the plasmid associated with the converging flow into the membrane pores. Transmission of the open circular DNA was significantly less than that of the supercoiled plasmid, while transmission of the linear DNA was considerably enhanced due to differences in conformational flexibility. New opportunities for enhancing DNA purification were identified using backpulsing to reduce fouling and using novel membranes with controlled pore morphology to pre-stretch the DNA in the elongation flow. The results clearly demonstrate the potential of using membrane systems for commercial-scale purification of DNA.
Dr. Andrew L. Zydney is currently Distinguished Professor of Chemical Engineering at The Pennsylvania State University, having served as Head of that Department from 2004-2014. Professor Zydney received his B.S. in Chemical Engineering from Yale in 1980 and his Ph.D. from M.I.T. in 1985. He was a faculty member in the Chemical Engineering Department at the University of Delaware from 1985 – 2001. Professor Zydney’s research is focused on membrane science and technology, with a particular emphasis on bioseparations and the purification of high value biological products. He has published more than 200 articles on these topics, including invited contributions to the Encyclopedia of Bioprocess Technology and the Handbook of Biomedical Engineering. He is the most recent recipient of the Excellence in Biological Engineering Publications Award from the AIChE. Professor Zydney is the Editor-in-Chief of the Journal of Membrane Science, and he serves on the Editorial Boards for Separation and Purification Reviews, Separation Science and Technology, Current Opinion in Chemical Engineering, and Biotechnology and Bioengineering. He served as President of the North American Membrane Society in 2002 – 2003, and was a member of the Board of Directors for 9 years. He was elected a Fellow of the American Institute of Medical and Biological Engineers, the American Institute of Chemical Engineers, and the American Association for the Advancement of Science. Dr. Zydney has received Excellence in Teaching Awards from the University of Delaware and the Penn State Engineering Alumni Society, and he is a past recipient of the Distinguished Teacher Award and the Outstanding Young Faculty Award from the American Society of Engineering Education.
Seminar – Ramanan Krishnamoorti
Interim Vice Chancellor/Vice President for Research and Technology Transfer
Chief Energy Officer
University of Houston
Hybrid Nanoparticles: Structure, Dynamics and Properties
Polymer grafted nanoparticles are fascinating materials that bridge the gap between colloidal particles and star-polymers. We have studied the structure and dynamics of highly grafted hybrid nanoparticles in the bulk and in dilute solutions and have elucidated the structure of the polymer chains and the arrangement of the nanoparticles as functions of polymer molecular weight and solvent quality. Extending these to polymer blends wherein the matrix (unattached) chains is attracted to the grafted polymer chains has allowed us to determine the relationship between segment compatibility and polymer dewetting. The consequences of the unique structure and dynamics of these grafted polymer chains on interfacial properties and as mobility control agents for enhanced oil recovery will be discussed in this talk.
Ramanan Krishnamoorti is the Interim vice chancellor/vice president for research and technology transfer and chief energy officer at the University of Houston. He has served as chair of the UH Cullen College of Engineering’s chemical and biomolecular engineering department, associate dean of research for engineering, professor of chemical and biomolecular engineering with affiliated appointments as professor of petroleum engineering and professor of chemistry. Dr. Krishnamoorti obtained his bachelor’s degree in chemical engineering from the Indian Institute of Technology Madras and doctoral degree in chemical engineering from Princeton University in 1994.
The Department of Biomedical Engineering & the Department of Chemical & Biomolecular Engineering Present the Following Seminar:
Speaker: Belinda Hurley, Associate Professor, Research and Education, OSU Libraries
The OSU Libraries spend many millions each year to provide resources that are not freely available online. Belinda Hurley, OSU Libraries’ liaison for Physical Sciences and Engineering, will present an overview of available resources and services to those new to the OSU Libraries system.