Mechanical Engineering Commons^™

A Comprehensive Optimized Model For On-Board Solar Photovoltaic System For Plug-In Electric Vehicles: Energy And Economic Impacts, Mahmoud M. Abdelhamid

Mahmoud M Abdelhamid

Muscle Synergies Improve Estimation Of Knee Contact Forces During Walking, Benjamin Fregly, Jonathan Walter, Allison Kinney, Scott Banks, Darryl D'Lima, Thor Besier, David Lloyd

Allison Kinney

This study investigates whether use of subject-specific muscle synergies can improve optimization predictions of muscle excitation patterns and knee contact forces during walking. Muscle synergies describe how a small number of neural commands generated by the nervous system can be linearly combined to produce the broad range of muscle electromyographic (EMG) signals measured experimentally. By quantifying the interdependence of individual EMG signals, muscle synergies provide dimensionality reduction for the neural control redundancy problem. Our hypothesis was that use of subjectspecific muscle synergies to limit muscle excitation patterns would improve prediction of muscle EMG patterns at the hip, knee, and ankle …

Muscle Synergy Constraints Improve Prediction Of Knee Contact Force During Gait, Benjamin Fregly, Jonathan Walter, Allison Kinney, Scott Banks, Darryl D'Lima, Thor Besier, David Lloyd

Allison Kinney

Knowledge of patient-specific muscle and joint contact forces during activities of daily living could improve the treatment of movement-related disorders (e.g., osteoarthritis, stroke, cerebral palsy, Parkinson’s disease). Unfortunately, it is currently impossible to measure these quantities directly under common clinical conditions, and calculation of these quantities using computer models is limited by the redundant nature of human neural control (i.e., more muscles than theoretically necessary to actuate the available degrees of freedom in the skeleton). Walking is a particularly important task to understand, since loss of mobility is associated with increased morbidity and decreased quality of life. Though numerous musculoskeletal …

Evaluation Of Different Optimal Control Problem Formulations For Solving The Muscle Redundancy Problem, Friedl De Groote, Allison Kinney, Anil Rao, Benjamin Fregly

Allison Kinney

This study evaluates several possible optimal control problem formulations for solving the muscle redundancy problem with the goal of identifying the most efficient and robust formulation. One novel formulation involves the introduction of additional controls that equal the time derivative of the states, resulting in very simple dynamic equations. The nonlinear equations describing muscle dynamics are then imposed as algebraic constraints in their implicit form, simplifying their evaluation. By comparing different problem formulations for computing muscle controls that can reproduce inverse dynamic joint torques during gait, we demonstrate the efficiency and robustness of the proposed novel formulation.

Synergies Controls Improve Prediction Of Knee Contact Forces And Muscle Excitations During Gait, Benjamin Fregly, Jonathan Walter, Allison Kinney, Scott Banks, Darryl D'Lima, Thor Besier, David Lloyd

Allison Kinney

This study investigates whether use of muscle excitation controls constructed from subjectspecific muscle synergy information can improve optimization prediction of knee contact forces and muscle excitations during walking. Muscle synergies quantify how a large number of experimental muscle electromyographic (EMG) signals can be reconstructed by linearly mixing a much smaller number of neural commands generated by the nervous system. Our hypothesis was that controlling all muscle excitations with a small set of experimentally calculated neural commands would improve prediction of knee contact forces and leg muscle excitations compared to using independently controlled muscle excitations.

Comparison Of Material Properties And Microstructure Of Specimens Built Using The 3d Systems Vanguard Hs And Vanguard Hiq+Hs Sls Systems, T.J. Silverman, Allison Kinney, W. Yong, J.H. Koo

Allison Kinney

The HiQ upgrade to the 3D Systems Vanguard selective laser sintering (SLS) machine incorporates a revised thermal calibration system and new control software. The paper compares the tensile modulus, tensile strength, elongation at break, flexural modulus, Izod impact resistance and microstructure of two batteries of standard specimens built from recycled Duraform PA (Nylon 12). The first set is built on a Vanguard HS system and the second on the same system with the HiQ upgrade installed. The upgrade reduces user intervention, decreases total build time and improves surface finish. However, using the default processing parameters, tensile, flexure and impact properties …

Rational Design Of Mixed Ionic And Electronic Conducting Perovskite Oxides For Solid Oxide Fuel Cell Anode Materials: A Case Study For Doped Srtio3, Suwit Suthirakun, Guoliang Xiao, Salai Ammal, Fanglin Chen, Hans-Conrad Zur Loye, Andreas Heyden

Salai C. Ammal

No abstract provided.

Mechanism Of Sulfur Poisoning Of Sr2Fe1.5Mo0.5O6-Δ Perovskite Anode Under Solid Oxide Fuel Cell Conditions, Eric Walker, Salai Ammal, Suwit Suthirakun, Fanglin Chen, Gabriel Terejanu, Andreas Heyden

Salai C. Ammal

No abstract provided.

Effects Of Nano Additives On Hydrogen Storage Behavior Of The Multinary Complex Hydride Libh4/Linh2/Mgh2., Sesha Srinivasan, Michael Niemann, Jason Hattrick-Simpers, Kimberly Mcgrath, Prakash Sharma, D. Goswami, Elias Stefanakos

Jason R. Hattrick-Simpers

No abstract provided.

Development Of Combined Optical Cell And Sieverts-Type Apparats For In-Situ Measurement Of Hydrogen Storage Materials, Chun Chiu, Jason Hattrick-Simpers, Edwin Heilweil, Leonid Bendersky

Jason R. Hattrick-Simpers

No abstract provided.

Raman Spectroscopic Observation Of Dehydration In Ball-Milled Linh2-Libh4-Mgh2 Nanoparticles, Jason Hattrick-Simpers, James Maslar, Michael Niemann, Chun Chiu, Sesha Srinivasan, Elias Stefanakos, Leonid Bendersky

Jason R. Hattrick-Simpers

No abstract provided.

Observation Of Phase Transitions In Hydrogenated Yttrium Films Via Normalized Infrared Emissivity, Jason Hattrick-Simpers, Ke Wang, Lei Cao, Chun Chiu, Edwin Heilweil, Robert Downing, Leonid Bendersky

Jason R. Hattrick-Simpers

No abstract provided.

Optical Cell For Combinatorial In Situ Raman Spectroscopic Measurements Of Hydrogen Storage Materials At High Pressures And Temperatures, Jason Hattrick-Simpers, Wilbur Hurst, Sesha Srinivasan, James Maslar

Jason R. Hattrick-Simpers

An optical cell is described for high-throughput backscattering Raman spectroscopic measurements of hydrogen storagematerials at pressures up to 10 MPa and temperatures up to 823 K. High throughput is obtained by employing a 60 mm diameter × 9 mm thick sapphire window, with a corresponding 50 mm diameter unobstructed optical aperture. To reproducibly seal this relatively large window to the cell body at elevated temperatures and pressures, a gold o-ring is employed. The sample holder-to-window distance is adjustable, making this cell design compatible with optical measurement systems incorporating lenses of significantly different focal lengths, e.g., microscope objectives and single element …

A Combinatorial Characterization Scheme For High-Throughput Investigations Of Hydrogen Storage Materials, Jason Hattrick-Simpers, Zhuopeng Tan, Hiroyuki Oguchi, Chun Chiu, Edwin Heilweil, James Maslar, Leonid Bendersky

Jason R. Hattrick-Simpers

No abstract provided.

Performance Investigation Of A Hybrid Renewable Power Generation And Storage System Using Systemic Power Management Models, Damianos Giaouris, Athanasios Papadopoulos, Chrysa Ziogou, Dimiptris Ipsakis, Spyors Voutetakis, Simira Papadopoulou, Panos Seferlis, Fotis Stergiopoulos, Costas Elmasides

Sakis Papadopoulos

Hybrid renewable power generation systems considering storage of energy and/or hydrogen involve considerable complexity as heterogeneous equipment need to be interconnected and activated or deactivated at different time instances. This work employs generic and flexible decision making models to develop complex power/hydrogen management strategies and investigate their performance on systems integrating multiple power generation and storage devices. These models significantly facilitate the analysis of both a standalone power generation and storage system forming a microgrid currently in operation as well as three interconnected microgrids of different functionalities considered in this work. These systems are used to investigate the performance of …

Green Scheduling For Radiant Systems In Buildings, Truong Nghiem, Madhur Behl, George Pappas, Rahul Mangharam

Rahul Mangharam

In this report we look at the problem of peak power reduction for buildings with electric radiant floor heating systems. Uncoordinated operation of a multi-zone radiant floor heating system can result in temporally correlated electricity demand surges or peaks in the building’s electricity consumption. As peak power prices are 200-400 times that of the nominal rate, this uncoordinated activity can result in high electricity costs and expensive system operation. We have previously presented green scheduling as an approach for reducing the aggregate peak power consumption in buildings while ensuring that indoor thermal comfort is always maintained. This report extends the …