Seminar Series Fast and sensitive detection of bacteria from dilute suspensions by combining Electrokinetics and micro-Raman spectroscopy David Liao ABSTRACT To prevent the spread of pathogens, fast and accurate detection methods for trace amounts of the target pathogen are crucial. Established methods that test for the presence of biologically infectious agents in dilute concentrations traditionally require cultivation to amplify the number of pathogens present. In this presentation, a method that combines micro-Raman spectroscopy and electrokinetic forces to detect bacteria at dilute concentrations without cultivation is discussed. The method is characterized by three key features, namely, accelerated transportation and focusing of bacteria to the detection surface by means of an electric field, selective capture of the target microorganism using surface-immobilized antibodies, and sensitive detection of target bacteria with micro-Raman spectroscopy. The electric field is created by an AC signal-driven planar, quadrupolar, gold microelectrode array that has been photolithographically embedded in the detection surface. Using this method, detection of Escherichia coli K12 (target microorganism) at concentrations as low as 102 bacteria/mL and within only a few minutes can be reproducibly achieved from 50 L sample droplets. Seminar Series Development of an ion-exchanger membrane for PDMS-based microfluidic devices Rio Festarini ABSTRACT The purpose of this research is to investigate a few potential methods to produce an ion-exchange membrane that can be integrated directly into a polydimethylsiloxane (PDMS) Lab on a Chip or Micro Total Analysis System. The DuPont product Nafion™ was chosen as the ion-exchange membrane, a copolymer with high conductivity to cations and suitable for many applications such as electrolysis of water and the chlor-alkali process. Through the use of the inherent properties of PDMS, very inexpensive sugar granulate can be used to make an inexpensive membrane mold which does not interfere with the PDMS crosslinking process. After dissolving away this sacrificial mold material, Nafion™ is solidified in the irregular granulate holes. Nafion™ in this membrane is restrained in the irregular shape of the PDMS openings. The outer structure of the membrane is all PDMS and can be attached easily and securely to any PDMS build Lab on a Chip through reversible or irreversible PDMS/PDMS bonding. Seminar Series Elemental Sulfur, a Source of Energy and Gypsum Production Yasmine Hajar ABSTRACT Canadian sulfur production from bitumen and natural gas has been raising environmental concerns regarding storage of sulfur in solid blocks. Long-term plans for handling, storing and using the sulfur are required. The proposed solution is to convert sulfur to electrical energy and environmentally benign calcium sulfate (gypsum) by reacting it with a source of calcite through the exothermic reaction: S(s) + CaCO3(s) +3/2 O2 → CaSO4(s) + CO2(g) ΔH⁰=-621 kJ/mol In this study, thermodynamic analysis of the proposed industrial-scale processes has shown the effect of changing the route and conditions of the reaction on the electrical efficiency of the system. The suggested main route is to combust sulfur in a turbine combined cycle, then react SO2 with calcite in a Flue Gas Desulfurization (FGD) system. At lab-scale, multiple set-ups were designed and built to study the high-temperature reaction and the effects of changing reactant ratio and temperature on sulfur conversion, in different gas conditions. The results were evaluated through thermogravimetric analysis and x-ray diffraction. Seminar Series Encapsulation and Release of Oseltamivir Phosphate and Gemcitabine from Monoglyceride Stabilized ‘Pickering’ Emulsions for Sustained Drug Delivery Kurt Wood ABSTRACT The sustained release of small hydrophilic drugs such as oseltamivir phosphate (OP) and gemcitabine is a significant challenge due to the rapid rate at which they are dispersed in tissue and bodily fluids. Encapsulation of these drugs in water-in-oil (W/O), monoglyceride stabilized emulsions may present a possible solution to this challenge. OP has been successfully encapsulated into a monoglyceride stabilized emulsion and a sustained release to an external aqueous phase has been demonstrated. This approach has the key advantage of utilizing inherently biocompatible, renewable materials in its formulation. Additionally, the monoglyceride stabilizer has been demonstrated to from pickering stabilized droplets which encapsulate the drug. Pickering stabilization provides enhanced steric stability against droplet coalescence, and imparts an enhanced diffusional barrier to drug release. During the course of this ongoing project, the emulsion formulation will be optimized to deliver the encapsulated drugs at a therapeutic rate. The feasibility of converting the emulsion to a water-in-oil-in-water (W/O/W) double emulsion for reduced viscosity will also be investigated. Seminar Series Delivery of Oseltamivir Phosphate and Gemcitabine from Poly (D, L-Lactic-co-Glycolic Acid) for the Treatment of Pancreatic Cancer Stephanie Allison ABSTRACT Pancreatic cancer is the fourth leading cause of cancer death in Canada and has a five-year survival rate of only 6%. The low survival rate is primarily due to late detection and resistance to chemotherapy. The current standard of care for unresectable pancreatic cancer is gemcitabine (GEM), but less than 6% of patients exhibit a reduction in tumor size following treatment. Our lab has identified neuraminidase 1 (Neu1) as a key player in growth factor activation, providing a novel therapeutic target for the treatment of pancreatic cancer. Oseltamivir phosphate (OP) is a Neu1 inhibitor and has been shown to inhibit tumor growth in RAG2xCγ double mutant mice. Implantable cylinders containing OP and GEM were developed using poly (D, L-lactic-coglycolic acid) as an encapsulation polymer, to enable drug delivery at the tumor site. The aim of the project is to develop a method of delivering OP and GEM over an extended period of time and to test the efficacy of the released drugs in vitro with the human pancreatic cancer cell line Panc1 and GEM-resistant Panc1. Seminar Series A New Optimization Model and a Customized Global Optimization Method for Design and Operation of Natural Gas Production Networks under Uncertainty Dan Li ABSTRACT The integrated design and operation problem for natural gas production networks is to determine the network design decisions, platform pressures and the gas flows in operation to achieve the best expected profit, while meeting the customer demands and product specifications. The existing methodologies either use an optimization model with limited details of the system or cannot ensure a globally optimal solution. This research aims to develop an improved optimization model that describes more details of the physical system. A reformulation of the proposed model exhibits a partially convex and block diagonal structure, and a bi-level decomposition method is developed to exploit this problem structure for efficient global optimization. Case study results of an industrial gas production system demonstrate the benefits of the proposed model and the optimization method. Seminar Series A New Robust Scenario Approach for Supply Chain Optimization under Bounded Demand Uncertainty Niaz Chowdhury ABSTRACT Supply Chain Optimization problem under uncertainty can be modeled as two stage optimization problem where first stage decision variables are associated with design of facilities and second stage decision variables are associated with operation of the supply chain network. Uncertainty in different parameter of supply chain network can be better dealt with robust scenario formulation which works better than the classical scenario formulation by ensuring feasibility and better expected economic performance. The most common uncertain parameter in supply chain network is demand and depending on the supply chain network, the uncertainty region can be of different shape. The main purpose of this presentation is to propose a systematic way to address any bounded uncertainty region in supply chain optimization. Any bounded uncertainty region can be divided into a number of box uncertainty subregions, each associated with a scenario. Screening processes are applied to the uncertainty subregions, leading to optimization problems with over-estimation and under-estimation of the original uncertainty region. When the number of scenarios increases, the optimal objective values of the two optimization problems converge to a constant, which is a good estimate of the true optimal value. Since the box uncertainty subregions are described by the infinity norm, the optimization problems to be solved have constraints involving 1- norm, and these constraints can be transformed into linear constraints. A supply chain network from DuPont will be used to demonstrate the effectiveness of the proposed approach. Seminar Series Geometric Based Estimation and Nonlinear PI Controller for Dynamic Optimization Problem Ehsan Moshksar ABSTRACT The subject of this talk is the minimization of an unknown but measurable cost function that is subject to unknown dynamics. An extremum-seeking algorithm is proposed to solve the black-box optimization problem. The Lie derivatives of the convex cost function with respect to nonlinear dynamics of the system are regarded as time-varying parameters. A new technique based on the concept of almost invariant manifolds is proposed for the adaptive estimation of the time-varying parameters. A nonlinear proportional-integral approach is then used to formulate the extremum-seeking controller. This approach is shown to avoid the need for a time-scale separation in real-time optimization problem. The effectiveness of the proposed method is illustrated with a simulation example. Seminar Series Observer design using potential based realizations Ryan Bennett ABSTRACT This presentation considers observer design for nonlinear dynamical system which can be approximated by a dissipative Hamiltonian realization. The design approach decomposes the system associated one-form of a given dynamical system over an indeterminate or a pre-determined time-invariant metric using the Homotopy operator to generate exact (potential driven) and anti-exact parts. Then the convexity of the potential system given by the exact part is assessed and a metric equation is proposed which yields a Lyapunov function for the potential driven observer system. Applications of the method are then shown using non-trivial (non-convergent) examples.
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