September 4, 2012
Dr. Tobias Hanrath, Cornell University
Seminar Abstract:
Controlling the composition and structure of materials at the nanometer scale provides unprecedented opportunities to create novel materials with properties by design. In particular, nanostructured materials offer an ideal experimental platform to evaluate structure/property relationships in quantum-confined systems that could ultimately provide technological value. Recent advances in synthesis, characterization, and the emerging understanding of their size-dependent properties have created exciting prospects for semiconductor nanomaterials to contribute to the development of next-generation energy conversion technologies. Semiconductor nanocrystal quantum dots are particularly attractive material candidates for the efficient capture of solar emission in inexpensive, thin film photovoltaic devices by virtue of their large absorption cross sections, low-cost solution-phase processing and size-tunable energy gaps. We review our recent work investigating the exciton dissociation and charge transport between quantum confined nanocrystals as a function of the interparticle spacing. Beyond controlling the interdot spacing, directing the nanocrystals into ordered superstructures with predefined translational and orientational order is a critical parameter for controlling the electronic coupling in three-dimensional superlattices. We will present recent experiments relating superlattice symmetry and optical properties of the ensemble.
November 13, 2012
Dr. Ignacio Grossman – Carnegie-Mellon University
Texas Distinguished Faculty Lectureship
(Reception to follow in CPE 2.802F)
Seminar Abstract:
In this presentation we give an overview of recent applications in Process Systems Engineering of new discrete and continuous optimization techniques. We first provide a brief overview of logic-based optimization methods, emphasizing the theoretical relation of the continuous relaxations between mixed-integer programming and generalized disjunctive programming for nonconvex optimization problems. We discuss approaches for solving these problems to global optimality, with the major aim being the prediction of tight lower bounds on the global optimum. Several applications are presented to highlight the recent advances of these techniques, and their impact for improving the design and operation of sustainable and robust process systems through creative mathematical modeling. In the area of sustainable process synthesis we consider as examples the synthesis of integrated process water systems, and the energy optimization of corn-based and lignocellulosic bio-ethanol plants in which we also illustrate the synergy between energy and water optimization. We also consider the application of mixed-integer optimization methods in the area of process operations under uncertainty where we consider the optimal design of responsive supply chains and optimal design of oil and gas offshore facilities. The former problem involves uncertainties in demands, while the latter involves uncertainties in the reservoir sizes and deliverabilities. Both problems have in common the goal of providing robustness to the operation of the process system.
April 26, 2012
Seminar Abstract:
One of the hardest things a potential entrepreneur struggles with is when to take the leap and how to know that their idea for creating the next new thing is actually a good one.
Dr. Swahney will use his last company, Confluent Surgical, as a case study to help budding entrepreneurs evaluate their ideas in an objective fashion. The talk will also lay out some of the steps required to take to structure an entrepreneurial business from technology evaluation, writing a business plan, fundraising, hiring, etc. The aim is to have an interactive and free flowing discussion.
March 1, 2011
Dr. Teplyakov will discuss how surfaces and interfaces play an important role in development of modern microelectronics, optoelectronics, biosensing and other fields.
This seminar will cover approaches to tune the properties of interfaces, surfaces, and subsurface layers of participating materials by chemical functionalization. Specifically, the amino-groups of a general formula NHx used to control surface reactions on semiconductor surfaces, to promote deposition schemes on surfaces of thin solid diffusion barrier films, and to provide reliable surface sites for biofunctionalization of self-assembled monolayers.
In all of these cases, the reactivity of the amino-group can be designed to fit the required application. Dr. Teplyakov’s group uses selected temperature regimes, alkyl, aryl, and other substituents to alter the reactivity of amino-terminated surfaces and to reversibly tune the properties of surface and subsurface layers in thin solid films and in “soft” self-assembled monolayers.
His research also compares the amino-functionalized surfaces with more traditional substrates, such as, for example, hydrogen-terminated semiconductor crystals. The preparation, analysis with multiple surface analytical microscopic and spectroscopic techniques, computational approaches to understanding surface reactivity, structure, and stability of these aminofunctionalized surfaces and interfaces will also be addressed.