Conferences, Lectures, & Seminars
Events for February
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Structure-Property Relations in Polymers for Gas Separations
Thu, Feb 11, 2010 @ 12:45 PM
Mork Family Department of Chemical Engineering and Materials Science
Conferences, Lectures, & Seminars
Lyman Handy Colloquium SeriesPresentsBenny D. FreemanUniversity of Texas at AustinAbstract:This presentation will discuss structural features important in the use of polymers as rate-controlling membranes for gas separations. In particular, materials having desirable combinations of high permeability and high selectivity based upon solubility selectivity (e.g., butane removal from natural gas, CO2 separation from H2 or N2) or diffusivity selectivity (e.g., CO2 removal from natural gas) will be presented. For example, cross-linked poly(ethylene oxide) (XLPEO) polymers, which are flexible, rubbery polymers identified as promising materials to remove polar and acid gases, such as CO2, from mixtures with light gases, such as H2. One member of this family of materials was reported to have a CO2 permeability coefficient of approximately 500 Barrer and a CO2/H2 mixed gas selectivity of 30 at -20C.1 Such materials achieve high selectivity based upon their high solubility selectivity favoring CO2 transport. Prepared by cross-linking low molecular weight poly(ethylene glycol) diacrylate with other poly(ethylene oxide) acrylates, XLPEO polymers exhibit good separation properties thanks to ethylene oxide group interaction with CO2 and suppression of crystallinity normally found in high molecular weight, linear poly(ethylene oxide).
Polymers can also be tailored to achieve high selectivity based upon high diffusivity selectivity. In this case, highly rigid, glassy polymers with proper free volume element size and size distribution are desirable. Polyimides with ortho-position functional groups may be solution-processed to form conventional films and membranes. Such materials can undergo thermal rearrangement to form highly rigid benzoxazole or benzithiazole structures having very high permeability coefficients and high selectivity. For example, one member of this family was prepared having a CO2 permeability coefficient of 1610 Barrer and a CO2/CH4 selectivity, under mixed gas conditions, of 42-46, depending on the partial pressure of CO2 in the mixture.2 These thermally rearranged (TR) polymers are insoluble in common solvents, giving them good chemical stability, and highly thermally stable, which are important attributes for membranes that would be used in chemically or thermally aggressive environments.
The overarching message from this presentation is that polymers can be exquisitely tuned to have favourable permeation properties. Materials may be designed to achieve high selectivity by being more soluble to one molecule than another or by having a strong ability to sieve gas molecules based on minute differences in gas molecule size. In both cases, the structure of the polymer may be optimized to permit rapid permeation.Location: James H. Zumberge Hall Of Science (ZHS) - 159
Audiences: Everyone Is Invited
Contact: Petra Pearce Sapir
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Predicting and tuning multicellular morphodynamics
Fri, Feb 19, 2010 @ 01:30 PM - 02:30 PM
Mork Family Department of Chemical Engineering and Materials Science
Conferences, Lectures, & Seminars
The Center for Applied Molecular Medicine (CAMM) at USC is proud to present Dr. Anand Asthagiri of Cal-Tech, Division of Chemistry & Chemical Engineering.
Abstract:
The cellular microenvironment controls the behavior of individual cells and their organization into multicellular structures. Uncovering how the microenvironment instructs the dynamical assembly of multicellular structures is a fundamental challenge in biology with profound implications in applications, such as tissue engineering and regenerative medicine. My lab uses quantitative experimental analysis and systems-level modeling to uncover design principles for engineering multicellular patterns and structures. I will describe the insights emerging from our studies of two model multicellular systems: the nematode C. elegans and human epithelial cell communities.
C. elegans provides a unique test bed for developing systems-level predictive models of multicellular patterning. We have developed a computational framework to construct a "phase diagram" of multicellular phenotypes. This phase diagram represents all the multicellular patterns predicted to occur in response to perturbing the underlying regulatory network. Unexpectedly, the predicted phenotypes are observed experimentally not only in C. elegans, but also exclusively in other species. Thus, the phase diagram offers a framework for tracing systematically how the molecular network has diversified during the evolution of C. elegans and related species.
Predicting the evolutionary trajectories of multicellular phenotypes is of interest not only in model organisms, but also in human cell systems. Misdirected evolution of multicellular phenotypes is the basis of diseases, such as cancer. Thus, we are applying automated single-cell imaging and micropatterning to better understand the assembly, disassembly and growth of human multicellular epithelial structures. Our results reveal how the quantitative interplay between cell-cell contact and global soluble cues regulates epithelial population growth and aggregation dynamics. I will discuss how these findings advance our current understanding of cancer development and provide design strategies for tissue engineering applications.Location: Grace Ford Salvatori Hall Of Letters, Arts & Sciences (GFS) - 106
Audiences: Everyone Is Invited
Contact: Beeta Benjy
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Nanogenerators for Self-Powered Nanosystems
Mon, Feb 22, 2010 @ 12:45 AM
Mork Family Department of Chemical Engineering and Materials Science
Conferences, Lectures, & Seminars
Nanogenerators for Self-Powered Nanosystems
Dr. Rusen Yang
School of Materials Science and Engineering
Georgia Institute of Technology
Atlanta, GAAbstract
A self-powered nanosystem that harvests its operating energy from the environment is an attractive proposition for sensing, medical science, defense technology, and even personal electronics. Therefore, it is essential to explore innovative nanotechnologies for converting mechanical energy (such as body movement), vibration energy (such as acoustic/ultrasonic wave), and hydraulic energy (such as blood flow) into electric energy that will be used to power nanodevices without using battery. Piezoelectric zinc oxide nanowire (NW) arrays have been successfully demonstrated to convert nano-scale mechanical energy into electric energy. The operation mechanism of the electric generator relies on the unique coupling of piezoelectric and semiconducting dual properties of ZnO as well as the elegant rectifying function of the Schottky barrier formed between the metal electrode and the NW. This mechanism resulted in the DC nanogenerator driven by ultrasonic wave. Recently we achieved a new breakthrough with laterally-packaged single wire generator, which solved the transient contact issue in DC nanogenerator and produced power output from low frequency and irregular mechanical disturbance, such as finger tapping and running hamster. This presentation will introduce the fundamental principle of nanogenerator and its potential applications.Location: Hedco Pertroleum and Chemical Engineering Building (HED) - 116
Audiences: Everyone Is Invited
Contact: Petra Pearce Sapir
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Nanogenerators for Self-Powered Nanosystems
Mon, Feb 22, 2010 @ 12:45 AM
Mork Family Department of Chemical Engineering and Materials Science
Conferences, Lectures, & Seminars
Nanogenerators for Self-Powered NanosystemsDr. Rusen YangSchool of Materials Science and EngineeringGeorgia Institute of Technology
Atlanta, GAAbstract A self-powered nanosystem that harvests its operating energy from the environment is an attractive proposition for sensing, medical science, defense technology, and even personal electronics. Therefore, it is essential to explore innovative nanotechnologies for converting mechanical energy (such as body movement), vibration energy (such as acoustic/ultrasonic wave), and hydraulic energy (such as blood flow) into electric energy that will be used to power nanodevices without using battery. Piezoelectric zinc oxide nanowire (NW) arrays have been successfully demonstrated to convert nano-scale mechanical energy into electric energy. The operation mechanism of the electric generator relies on the unique coupling of piezoelectric and semiconducting dual properties of ZnO as well as the elegant rectifying function of the Schottky barrier formed between the metal electrode and the NW. This mechanism resulted in the DC nanogenerator driven by ultrasonic wave. Recently we achieved a new breakthrough with laterally-packaged single wire generator, which solved the transient contact issue in DC nanogenerator and produced power output from low frequency and irregular mechanical disturbance, such as finger tapping and running hamster. This presentation will introduce the fundamental principle of nanogenerator and its potential applications.Location: Hedco Pertroleum and Chemical Engineering Building (HED) - 116
Audiences: Everyone Is Invited
Contact: Petra Pearce Sapir
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Nano-enabled energy technologies
Thu, Feb 25, 2010 @ 12:45 AM
Mork Family Department of Chemical Engineering and Materials Science
Conferences, Lectures, & Seminars
Distinguished Lecture SeriesPresentsZ. L. WangGeorgia Institute of TechnologyAbstract:Abstract
Developing novel technologies for wireless nanodevices and nanosystems are of critical importance for sensing, medical science, defense technology and even personal electronics. It is highly desired for wireless devices and even required for nanodevices to be self-powered without using battery. It is essential to explore innovative nanotechnologies for converting mechanical energy, vibration energy, and hydraulic energy into electric energy, aiming at building self-powered nanosystems. We have demonstrated innovative approaches for converting mechanical energy into electric energy by piezoelectric zinc oxide nanowire (NW) arrays. Based on the piezoelectric potential created by strain in nanowires and in conjunction with the presence of a Schottky barrier at the contact, our research has demonstrated the technological road map from fundamental science, engineering scale-up to technological applications of the nanogenerators. As of today, we have demonstrated âself-poweredâ nanosensors that work by harvesting energy from the environment. In addition, three-dimensional solar cells have been fabricated by integrating optical fiber with nanowires for developing âhiddenâÂ, concealed and high efficiency solar cells. This talk will focus on the energy technologies developed using ZnO nanowires as the platform.Location: James H. Zumberge Hall Of Science (ZHS) - 159
Audiences: Everyone Is Invited
Contact: Petra Pearce Sapir