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Full-Text Articles in Engineering

Modified Cpd Model For Coal Devolatilization At Underground Coal Thermal Treatment Conditions, Ding Wang, Thomas H. Fletcher, Swomitra Mohanty, Hoaquan Hu, Eric G. Eddings Jan 2019

Modified Cpd Model For Coal Devolatilization At Underground Coal Thermal Treatment Conditions, Ding Wang, Thomas H. Fletcher, Swomitra Mohanty, Hoaquan Hu, Eric G. Eddings

Faculty Publications

To study coal pyrolysis behavior at underground coal thermal treatment (UCTT) conditions, a modified CPD (M-CPD) model was developed and evaluated using two scales of experiments as well as two different coals, Utah Sufco and Illinois #6. Compared with the original CPD model, three major aspects were changed, including (1) rewriting the algorithm using MATLAB built-in functions; (2) developing a correlation method between coal elemental composition and the initial functional group population to calculate the effect of cross-linking on the lattice structure; and (3) using a two-activation energy approach for gas generation kinetics modeling. Results predicted by the M-CPD model …


Characterization Of Pyrolysis Products From Slow Pyrolysis Of Live And Dead Vegetation Native To The Southern United States, Elham Amini, Mohammad-Saeed Safdari, Jonathan Deyoung, David R. Weise, Thomas H. Fletcher Jan 2019

Characterization Of Pyrolysis Products From Slow Pyrolysis Of Live And Dead Vegetation Native To The Southern United States, Elham Amini, Mohammad-Saeed Safdari, Jonathan Deyoung, David R. Weise, Thomas H. Fletcher

Faculty Publications

Prescribed (i.e., controlled) burning is a common practice used in many vegetation types in the world to accomplish a wide range of land management objectives including wildfire risk reduction, wildlife habitat improvement, forest regeneration, and land clearing. To properly apply controlled fire and reduce unwanted fire behavior, an improved understanding of fundamental processes related to combustion of live and dead vegetation is needed. Since the combustion process starts with pyrolysis, there is a need for more data and better models of pyrolysis of live and dead fuels. In this study, slow pyrolysis experiments were carried out in a pyrolyzer apparatus …


The Effect Of Communication And Vehicle Properties On The Search Performance Of A Swarm Of Unmanned Aerial Vehicles, Jenna E. Newcomb, Andrew Ning Jan 2019

The Effect Of Communication And Vehicle Properties On The Search Performance Of A Swarm Of Unmanned Aerial Vehicles, Jenna E. Newcomb, Andrew Ning

Faculty Publications

An unmanned aerial vehicle (UAV) swarm allows for a more time-efficient method of searching a specified area than a single UAV or piloted plane. There are a variety of factors that affect how well an area is surveyed. We specifically analyzed the effect both vehicle properties and communication had on the swarm search performance. We used non-dimensionalization to examine the effect vehicle properties had on search performance so the results can be applied to any domain size with any number and type of vehicle. We found that even if vehicles could only sense 10% of the grid area at any …


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 …


Combined Trajectory, Propulsion, And Battery Mass Optimization For Solar-Regenerative High-Altitude Long Endurance Unmanned Aircraft, Nathaniel S. Gates, Kevin R. Moore, Andrew Ning, John D. Hedengren Jan 2019

Combined Trajectory, Propulsion, And Battery Mass Optimization For Solar-Regenerative High-Altitude Long Endurance Unmanned Aircraft, Nathaniel S. Gates, Kevin R. Moore, Andrew Ning, John D. Hedengren

Faculty Publications

Combined optimization of propulsion system design, flight trajectory planning and battery mass optimization for solar-regenerative high-altitude long endurance (SRHALE) aircraft through a sequential iterative approach yields an increase of 20.2% in the end-of-day energy available on the winter solstice at 35 deg N latitude, resulting in an increase in flight time of 2.36 hours. The optimized flight path is obtained by using nonlinear model predictive control to solve flight and energy system dynamics over a 24 hour period with a 15 second time resolution. The optimization objective is to maximize the total energy in the system while flying a station-keeping …