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Stainless-Steel Column For Robust High Temperature Microchip Gas Chromatography, Abhijit Ghosh, Austin R. Foster, Jacob C. Johnson, Carlos R. Vilorio, Luke T. Tolley, Brian D. Iverson, Aaron R. Hawkins, H. Dennis Tolley, Milton L. Lee Dec 2019

Stainless-Steel Column For Robust High Temperature Microchip Gas Chromatography, Abhijit Ghosh, Austin R. Foster, Jacob C. Johnson, Carlos R. Vilorio, Luke T. Tolley, Brian D. Iverson, Aaron R. Hawkins, H. Dennis Tolley, Milton L. Lee

Faculty Publications

This paper reports the first results of a robust, high performance, stainless-steel microchip gas chromatography (GC) column that is capable of analyzing complex real world mixtures as well as operating at very high temperatures. Using a serpentine design, a 10 m column with an approximately semicircular cross section with a 52 µm hydraulic diameter (Dh) was produced in a 17 cm x 6.3 cm x 0.1 cm rectangular steel chip. The channels were produced using a multilayer chemical etch and diffusion bonding process, and metal nuts were brazed onto the inlet and outlet ports allowing for column ...


Takeoff And Performance Tradeoffs Of Retrofit Distributed Electric Propulsion For Urban Transport, Kevin Moore, Andrew Ning Aug 2019

Takeoff And Performance Tradeoffs Of Retrofit Distributed Electric Propulsion For Urban Transport, Kevin Moore, Andrew Ning

Faculty Publications

While vertical takeoff and landing aircraft have shown promise for urban air transport, distributed electric propulsion on existing aircraft may offer immediately implementable alternatives. Distributed electric propulsion could potentially decrease takeoff distances enough to enable thousands of potential inter-city runways. This conceptual study explores the effects of a retrofit of open-bladed electric propulsion units. To model and explore the design space we use blade element momentum method, vortex lattice method, linear-beam finite element analysis, classical laminate theory, composite failure, empirically-based blade noise modeling, motor and motor-controller mass models, and gradient-based optimization. With liftoff time of seconds and the safe total ...


Simulated Tremor Propagation In The Upper Limb: From Muscle Activity To Joint Displacement, Thomas Corie, Steven Knight Charles Aug 2019

Simulated Tremor Propagation In The Upper Limb: From Muscle Activity To Joint Displacement, Thomas Corie, Steven Knight Charles

Faculty Publications

Although tremor is the most common movement disorder, there are few non-invasive treatment options. Creating effective tremor suppression devices requires a knowledge of where tremor originates mechanically (which muscles) and how it propagates through the limb (to which degrees of freedom, DOF).

To simulate tremor propagation, we created a simple model of the upper limb, with tremorogenic activity in the 15 major superficial muscles as inputs and tremulous joint displacement in the 7 major DOF as outputs. The model approximated the muscle excitation-contraction dynamics, musculoskeletal geometry, and mechanical impedance of the limb.

From our simulations, we determined fundamental principles for ...


Influence Of Micro-Structured Superhydrophobic Surfaces On Nucleation And Natural Convection In A Heated Pool, Adam Cowley, Daniel Maynes, Julie Crockett, Brian D. Iverson Feb 2019

Influence Of Micro-Structured Superhydrophobic Surfaces On Nucleation And Natural Convection In A Heated Pool, Adam Cowley, Daniel Maynes, Julie Crockett, Brian D. Iverson

Faculty Publications

This word experimentally explores sub-boiling pool nucleation on micro-structured superhydrophobic surfaces. All surfaces tested were submerged in a 20 mm deep pool of water and heated from below to maintain a constant surface temperature, while the side walls of the pool were insulated, and the top was covered. Three thermocouples positioned in the pool obtain the average pool temperature. A heat flux sensor is placed directly beneath the surface to measure the heat flux supplied to the pool. Free convection heat transfer coefficients are obtained for the sub-boiling temperature range of 40 – 90 ºC. Six surface types are studied: smooth ...


Optimization Of Turbine Design In Wind Farms With Multiple Hub Heights, Using Exact Analytic Gradients And Structural Constraints, Andrew P.J. Stanley, Andrew Ning, Katherine Dykes Jan 2019

Optimization Of Turbine Design In Wind Farms With Multiple Hub Heights, Using Exact Analytic Gradients And Structural Constraints, Andrew P.J. Stanley, Andrew Ning, Katherine Dykes

Faculty Publications

Wind farms are generally designed with turbines of all the same hub height. If wind farms were designed with turbines of different hub heights, wake interference between turbines could be reduced, lowering the cost of energy (COE). This paper demonstrates a method to optimize onshore wind farms with two different hub heights using exact, analytic gradients. Gradient-based optimization with exact gradients scales well with large problems and is preferable in this application over gradient-free methods. Our model consisted of the following: a version of the FLOw Redirection and Induction in Steady-State wake model that accommodated three- dimensional wakes and calculated ...