Departmental Seminars

Fall 2016

 

Aug 22, 2016
10:40 AM
Room 1011, EB1

Mr. Ken Kretchman
NCSU Environmental Health & Safety

It is known that reviewing case studies from accidents and incidents is a useful tool for bringing hazards and recommended corrective action to the attention of those who need to know.  In addition, the process of conducting hazard reviews using a particular methodology, coupled with review of lessons learned which illustrate key indicient prevention concepts, can provide useful information for training of present and future students.

This presentation will match case studies with these key incident prevention concepts, which can be applied to present and future experiments, also  addressing the challenge of management of change in a research environment.. an environment where both personnel and experimental parameters are subject to frequent change.

Aug 29, 2016
10:40 AM
Room 1011, EB1

Dr. Buddie Mullins
University of Texas at Austin

Electrical energy storage is an enabling technology that will become more and more important, world-wide, with time.  In order to contribute to the development of this technology and its’ workforce my research group has been studying anode materials for lithium-based batteries.

This seminar will provide an overview of the operation of lithium batteries and discuss two studies that we have completed related to the negative electrode (i.e., the anode): (i) the discovery of germanium sub-selenide and the promising intrinsic lithiation/de-lithiation properties it possesses and (ii) research involving the science and mitigation of dendrites when lithium metal is employed as an electrode.

Sept 12, 2016
10:40 AM
Room 1011, EB1

Dr. Steven Cramer
Rensselaer Polytechnic Institute

This presentation will focus on recent developments in our lab in three areas of downstream bioprocessing; multimodal chromatography, affinity precipitation and integrated bioprocessing.

Fundamental studies into the nature of selectivity in multimodal chromatography will first be presented. This work will include chromatographic studies with various protein and multimodal ligand libraries, all-atom explicit Molecular Dynamics (MD) simulations and a range of biophysical studies to shed insight into the underlying nature of selectivity in these important new classes of chromatographic materials.

New predictive approaches will also be presented including course grained protein binding maps and quantitative structure activity relationship (QSAR) models using new classes protein molecular descriptors. Work will then be presented on affinity precipitation using smart biopolymers for the simultaneous recovery and purification of biological products. ELP-Z is employed for mAb purification and the process is shown to result in more than 2 logs of HCP and more than 4 logs of DNA clearance from the harvest feed with clearance and yield values comparable or superior to Protein A chromatography. Scale-up of the ELP-Z based mAb affinity precipitation process is successfully carried out using a combination of tangential flow microfiltration and dead end filtration for the recovery of the precipitates. This process is then extended to ELP-affinity peptides and proof of concept is demonstrated with two peptide affinity systems.

Finally, some results are presented on the development of integrated biomanufacturing systems using both affinity peptide capture as well as an optimized series of multimodal chromatographic operations.

Sept 19, 2016
10:40 AM
Room 1011, EB1

Dr. Tim White
Air Force Research Laboratory

It has been long-known that liquid crystalline materials in polymeric forms also exhibit exceptional characteristics in high performance applications as transparent armor or bulletproof vests as well as in optics and photonics. A specific class of liquid crystalline polymeric materials referred to as liquid crystalline elastomers were predicted by de Gennes to have exceptional promise as artificial muscles, owing to the unique assimilation of anisotropy and elasticity. Subsequent experimental studies have confirmed the salient features of these materials, with respect to other forms of stimuli-responsive soft matter, are actuation cycles of up to 400% as well “soft elasticity” (stretch at minimal stress).

In the presentation, I will summarize our recent efforts in developing materials chemistry amenable to allowing arbitrary local control of the anisotropy within these materials.  Enabled by these approaches, we have prepared complex actuators and mechanical elements from these materials. Notably, these materials are subject to mechanical design but homogenous in composition (lacking material/material interfaces). Relevance of this work to implementations in aerospace and commercial applications will be discussed.

Sept 26, 2016
10:40 AM
Room 1011, EB1

Dr. Yanhui Yang
Nanyang Technological University

Catalysis plays a key role in the global attempt to reduce carbon footprint by replacing the fossil feedstock with renewable resources, reducing energy consumption, and/or intensifying chemical processes for improved carbon efficiency. In this seminar, two examples will be discussed to illustrate our efforts in the last few years in biomass transformation.

The first example integrates experimental and computational investigations to reveal that the surface lattice oxygen of copper oxide activates the formyl C–H bond in glucose to form gluconic acid. The reduced CuO catalyst regains its structure, morphology and activity upon re-oxidation. The activity of lattice oxygen is shown to be superior to that of the chemisorbed oxygen on the metal surface and the hydrogen abstraction ability of the catalyst is correlated with the adsorption energy. Based on the present investigation, it is suggested that surface lattice oxygen is critical for the oxidation of glucose to gluconic acid, without further breaking down the glucose molecule into smaller fragments. Using CuO as the catalyst, excellent yield of gluconic acid is also obtained for the direct oxidation of cellobiose and polymeric cellulose.

The second example shows the Au-Pd bimetallic catalyst and its application in selective oxidation of HMF to FDCA. The unique structure of selected support is found to improve the stabilization of the metals in the preparation as well as the reaction process. Furthermore, surface chemistry (metal-support interaction) and synergetic effect in the case of metal alloy catalysts (metal-metal interaction) play a crucial role in controlling the catalytic performance of as-prepared catalysts. Various characterizations will be carefully conducted to look into the insights of these catalysts’ physicochemical properties.

Sept 27, 2016
3:45 PM
BTEC Room, 135

Scott Shell
University of Santa Barbara

MRSEC Seminar Series

Interfaces can direct the self-assembly of materials in unique ways that leverage new and often competing thermodynamic driving forces not found in the bulk. We use molecular simulations and theory to identify relevant interaction forces and then systematic design strategies for two such classes of materials. In the first part of the talk, we examine self-assembly as route to chiral surfaces made from achiral molecules. We show that a surprisingly simple mechanism, based only on excluded volume interactions, can drive achiral particles into chiral materials. The mechanism quantitatively explains recent experimental results, predicts new chiral-prone shapes, and suggests a way that chiral structures might emerge in nature. In the second part, we show that polymers can modulate the folding of proteins attached to an interface in ways distinct from bulk. Simulations reveal that conjugating a polymer to a model protein sometimes stabilizes and sometimes destabilizes the native helical fold, in an apparent non-intuitive manner depending on the precise attachment point. We show that these unexpected results are actually well-understood in terms of a simple theory that accounts for the entropy of the polymer near an impenetrable surface. 

Oct 3, 2016
10:40 AM
Room 1011, EB1

Dr. Venkat Venkatasubramanian
Columbia University

“Who is Bram Stoker?” – With this $1 million prize winning final question in the game show Jeopardy, IBM’s Watson supercomputer using DeepQA technology ushered in a new era in artificial intelligence and informatics. Welcome to the era of deep neural networks and selfdriving cars! This has far reaching implications for knowledge management in a number of fields including process systems engineering.

Driven by a convergence of powerful forces such as the great progress in molecular sciences and computer/communications technologies, ever increasing automation of globally integrated operations of our enterprises, tightening regulatory constraints, and competitive business pressures demanding speed to market for products and services, our discipline is in an unprecedented transition. One important common outcome from this convergence is the generation, use, and management of massive amounts of diverse data, information, and knowledge. Such a data deluge is coming from smart sensors in process plants, ab initio quantum calculations, molecular dynamics simulations, and so on. We are moving from an era of limited data obtained through time consuming experiments and simulations to one of a tsunami enabled by high throughput experiments and TeraGrid computing environments.

But it is not raw data that we are after. What we desire are in-depth knowledge and mechanistic, first-principles based, understanding of the underlying phenomena that can be modeled to aid us in rational decision making. However, knowledge extraction and model development from this data deluge pose unprecedented challenges, as well as offer tremendous opportunities. Past approaches developed in a “data poor” era do not work well in this new world.

The new environment requires imaginative thinking and innovative approaches in process systems engineering to address these challenges. This is where Artificial Intelligence and Data Science concepts and breakthroughs, as seen in Watson, will play a crucial role. In this lecture, I will discuss the challenges, opportunities and emerging trends using case studies drawn from diverse areas such as molecular products design, pharmaceutical manufacturing and systemic risk management in complex plants.

Oct 10, 2016
10:40 AM
Room 1011, EB1

Dr. Jason Bara
University of Alabama

 In comparison to other methods of radical polymerization, photopolymerization reactions offer multiple advantages including a greater degree of spatial and temporal control.  However, as these processes are often performed in bulk conditions, they are subject to mass transfer limitations that result in relatively poor polymerization kinetics.  To address this problem, multiple types of structured media have been examined, but lack direct applicability to commodity monomers and polymers.  In our recent work, we have examined coordinated ionic liquids (ILs) produced from the bistriflimide (Tf2N-) anion and polar organic monomers (e.g. methyl methacrylate) coordinated to Li+ cations.  We have shown that the presence of LiTf2N improves overall monomer conversion, photopolymerization kinetics and polymer MW and that the LiTf2N can be recovered quantitatively post-polymerization.  This approach offers facile introduction of high concentrations of metal salts into non-ionic polymer materials and produces customizable photocurable resins for applications such as 3-D printing.

Polyimides and ionic liquids (ILs) have each emerged as promising classes of materials for advanced membranes, especially with regard to CO2 removal from flue gas or natural gas. Despite their seemingly disparate natures, our group has developed methodologies by which these two very distinct materials are hybridized into a single, highly tailorable and robust structure.  The use of alternating, covalent linkages of imide segments and ionic segments presents unprecedented opportunities to design new materials featuring unique nanostructures/free volume characteristics that arise from supramolecular assembly.  This presentation will detail our design philosophy, synthetic methods, polymer structure-property relationships and initial performance as gas separation membranes.

Oct 17, 2016
10:40 AM
Room 1011, EB1

Dr. Scott Banta
Columbia University

There is an increasing interest in using chemolithoautotrophic bacteria for chemical and fuel production as they are able to use CO2 as a carbon feedstock.  Acidithiobacillus ferrooxidans are acidophiles that derive energy from the oxidation of iron or sulfur and thus their growth can be powered by renewable electricity or by the oxidation of sulfidic ores. We have recently genetically modified the cells with two different metabolic pathways. One cell line is able to produce isobutyric acid and another cell line produces heptadecane. We have also been exploring new endogenous promoter sequences to enable metabolic control over product formation. Media optimization experiments have been performed, and wild type cell growth, yield, and maintenance are improved when an iron chelator (citrate) is included in the medium formulation. This enables growth at higher pH and reduces ferric inhibition, and these additions also significantly improved the production of isoburyrate and heptadecane.

We have also explored alternative energy carriers in the media formulation and the vanadium redox couple was found to be an alternative method to deliver energy to the cells. We have explored different reactor configurations and found that a chemostat coupled with a recirculating electrochemical cell could be used to significantly increase cell densities in the bioreactor, leading to increased production of isobutyric acid from electricity. In collaboration with a major US copper mining company, we are exploring the production of chemicals from sulfide rich ores, which could result in the economic co-production of biochemicals during mining operations – proving that reduced metals in the Earth’s crust may be an untapped feedstock for energy production. A comparison of the efficiency of this system to current agriculture-based bioproduction platforms will be presented.

Oct 24, 2016
10:40 AM
Room 1011, EB1

Dr. Benjamin Hackel
University of Minnesota

Biology is dynamically driven by non-covalent interactions, predominantly involving proteins. The ability to study biological systems as well as engineer them for benefit – in medical and industrial settings – is dependent upon the ability to control these protein-protein interactions. With regards to personalized medicine, molecular targeting agents for medical imaging and targeted therapy have been limited by suboptimal physiological transport, non-specific retention, and inefficiency of binder evolution related to library design and target fidelity. The seminar will highlight advances in each of these elements with a focus on engineering synthetic binding ligands for molecular imaging. Non-invasive in vivo imaging at the molecular level is a powerful clinical approach for the detection, characterization, and monitoring of disease.

I will discuss an algorithm to efficiently evaluate naturally occurring protein domains for their evolutionary capacity and the resultant development of a small (5 kDa) scaffold capable of efficient evolution of high affinity binding functions. This scaffold, termed Gp2, was engineered to create synthetic ligands for binding various clinical biomarkers including insulin receptor and epidermal growth factor receptor (EGFR) for breast cancerimaging, as well as oligomeric -synuclein for neuropathological targeting. An evolved Gp2 was site-specifically radiolabeled with 64-Cu to enable molecular positron emission tomography of EGFR with superior performance relative to alternative radiotracers.

To improve the efficiency of evolving ligands towards clinical biomarkers, we demonstrate strong evolutionary benefit of site-specifically biased amino acid distributions within combinatorial libraries and highlight their relation to natural antibody repertoires. We empower ligand engineering towards biomarkers integrated in cellular membranes via enhanced selection techniques. Lastly, we demonstrate an efficient evolutionary approach to modulate charge density on the surface of protein ligands, while retaining biophysical integrity, to improve physiological targeting.

Oct 31, 2016
10:40 AM
Room 1011, EB1

Dr. Ashley Brown
NCSU

Proper wound healing is the result of a large number of interrelated biological events, which are orchestrated temporally in response to the injury microenvironment. These events can be categorized into four overlapping phases – the hemostatic phase, the inflammatory phase, the proliferation stage, and the remodeling stage. The extracellular matrix (ECM) plays a pivotal role in each of these stages by providing structural support and biological cues to infiltrating inflammatory cells, fibroblasts, endothelial cells and epithelial cells. Fibrin, fibronectin, and collagen are important ECM proteins in each of these stages. Fibrin is critical to hemostasis and forms the basis of the clot to stop bleeding. Fibronectin plays many roles in wound healing and directs cell adhesion, migration, proliferation and differentiation, all of which are critical to repopulating the damaged tissue. In the later stages of wound healing, collagen deposition in the wound site by fibroblasts forms the basis of the permanent replacement tissue. This process is impaired in chronic wounds and fibrosis, which correspond to impaired and excessive ECM deposition, respectively. In this talk, I will discuss engineering strategies to modulate the wound repair process through ECM-centric strategies, including 1) the development of fibrin targeting particles for augmentation of hemostasis and 2) modulation of ECM mechanics to control cytokine activation, epithelial to mesenchymal transitions, and cell migration to promote wound closure while minimizing scar tissue formation.

Nov 3, 2016
4:30 PM
BTEC Room 135

Dr. Alexey Snezhko
Argonne National Laboratory

MRSEC Seminar Series

Magnetic colloidal ensembles subject to an external energy injection often develop nontrivial collective dynamics and self-assembled phases. Dispersions of magnetic particles suspended at a liquid-air or liquid-liquid interface and driven far-from equilibrium by a transversal alternating magnetic field develop nontrivial dynamic self-assembled structures [1-3]. Experiments revealed new types of nontrivially ordered phases (“asters”, “magnetic snakes”) emerging in such systems in a certain range of excitation parameters. These remarkable magnetic non-equilibrium structures emerge as a result of the competition between magnetic and hydrodynamic forces. Above certain frequency threshold some of the dynamic magnetic structures spontaneously break the symmetry of self-induced surface flows (symmetry breaking instability) and turn into swimmers [3]. Nontrivial active self-assembly have been also observed in seemingly “trivial” geometries: suspended magnetic ensemble driven out of equilibrium by uniaxial alternating magnetic fields applied parallel to the liquid interface [4]. New dynamic self-assembled structures are reported, ranging from gas of rotators to dynamic wires. Transitions between different self-assembled phases with parameters of external driving magnetic field are observed.

I will also briefly discuss a set of very recent experiments on ferromagnetic micro-particles sediment on the bottom surface of the flat cell that are energized by a single-axis homogeneous alternating magnetic field applied perpendicular to the surface supporting the particles. Upon application of the field the magnetic torque on each particle is transferred to the mechanical torque giving rise to a rolling motion of the particle. Experiments reveal a rich collective dynamics of magnetic rollers in a certain range of excitation parameters. Flocking and spontaneous formation of steady vortex motions have been observed. The effects are fine-tuned and controlled by the parameters of the driving magnetic field. Formation of the self-organized collective states spontaneously breaking the symmetry of the underlying interactions has been attributed to the interplay of inelastic inter-particle collisions and self-induced hydrodynamic flows in the system.

Nov 21, 2016
10:40 AM
Room 1011, EB1

Dr. Yuan Yao
NCSU

The development and deployment of emerging technologies for energy- and resource-efficient chemical processes is critical for improving the sustainability of manufacturing industries while ensuring continued economic growth. Assessing the potential energy, environmental, and economic impacts of such technologies and identify the sustainable pathways can provide policy makers with insights useful for future investment and technology deployment; it also provides manufacturers and researchers with quantitative understandings of technology potential, possible bottlenecks, and future RD&D directions. However, the assessment of emerging technologies and analyzing alternative pathways are challenging for lack of process data, general evaluation approaches across different products, and robust methodologies over the large temporal and spatial scales.

This presentation will discuss novel systems analysis frameworks that are being developed to quantify the net energy, emissions, and economic implications of technology changes for U.S. chemical production systems and evaluate their effects on the economy from a life cycle perspective. These frameworks systematically integrate engineering, economic, and environmental life cycle models and statistical analysis to enable robust engineering and policy decisions. Examples of how these modeling frameworks can enhance decision-making related to the development and adoption of carbon capture technology, energy-efficient process technologies, and renewable energy technologies will be presented.

Dr. Hongliang Xin
Virginia Tech

Electrochemical reduction of CO2 , if coupled with hydrogen (H2 ) from (photo-)electrocatalytic water splitting, provides a promising solution for the utilization of the abundant greenhouse gas in the Earth’s atmosphere and the intermittent electrical energy from solar panels and wind turbines for fuels and chemicals that are traditionally derived from petroleum. Unfortunately, there are currently no catalysts capable of carrying out those reactions with both high activity and selectivity. Tailoring the local chemical reactivity of catalyst sites by alloying with other metal atoms in the transition metals and/or their oxides could potentially reduce the energy loss for CO2 reduction and H 2 O oxidation, and enhance the Faraday efficiency to desired products. While the traditional trial-and- error method for catalyst development usually relies on chemical intuition is time consuming, recent emergence of a descriptor-based materials design approach has significantly improved this and allows the discovery of more efficient catalysts from first-principles. In this talk, I will discuss our mechanistic studies of electrochemical CO 2 reduction on metals, and develop a machine-learning enabled screening approach that explores the wide geometrical and chemical phase space for catalysts discovery.