Mechanical Engineering Commons^™

Wave Propagation In Metamaterial Using Multiscale Resonators By Creating Local Anisotropy, Raiz U. Ahmed, Sourav Banerjee

Faculty Publications

Directional guiding, passing or stopping of elastic waves through engineered materials have many applications to the engineering fields. Recently, such engineered composite materials received great attention by the broader research community. In elastic waves, the longitudinal and transverse motion of material particles are coupled, which exhibits richer physics and demands greater attention than electromagnetic waves and acoustic waves in fluids. Waves in periodic media exhibit the property of Bragg scattering and create frequency band gaps in which the energy propagation is prohibited. However, in addition to the Bragg scattering, it has been found that local resonance of artificially designed resonators …

Simulation Studying Effects Of Multiple Primary Aberrations On Donut-Shaped Gaussian Beam, Chen Zhang, K. Wang, J. Bai, Y. Liu, Guiren Wang

Faculty Publications

In this paper, we demonstrate the variation of donut-shaped depletion pattern which influenced by multiple primary aberrations. The simulation is base on a common stimulation emission of depletion (STED) system composed by Gaussian laser and vortex phase plate. The simulation results are helpful guidelines for analyzing the aberration of depletion patterns in real situations.

Water Management Capabilities Of Bio-Inspired Flow Field Configurations For Polymer Electrolyte Membrane Fuel Cells, Nicholas Warren Freer

Masters Theses

"Fuel cells have received an increasing amount of attention over the past decade for their power production capabilities. Polymer electrolyte membrane (PEM) fuel cells in particular are researched because of their high power density, large range of operating conditions, green products, and ease of scalability. PEM fuel cells do have a number of issues that reduce their overall performance. These issues include variations in reactant distribution, materials issues for the bipolar plate, and flooding caused by poor water management. Variations in the reactant distribution causes lower overall power output due to regions of low reactant density. This means that optimizing …

Robustness Of A Derivative-Free Adaptive Control Law In The Presence Of Unmodeled Dynamics, Tansel Yucelen, Anthony J. Calise

Mechanical and Aerospace Engineering Faculty Research & Creative Works

Although adaptive control theory offers mathematical tools to achieve required system performance without excessive dependence on modeling, its application to safety-critical systems can be limited by the presence of unmodeled dynamics. This paper examines the robustness to unmodeled dynamics of a recently developed derivative-free adaptive control law. In contrast to derivative-based adaptive laws it is shown, using a Lyapunov-Krasovskii functional, that robustness to unmodeled dynamics is improved by increasing the adaptation gain. This is accomplished by including a bias term in the set of basic functions employed by the adaptive control law. It is shown that derivative-based adaptive laws do …

Neuropredictive Control And Trajectory Generation For Slung Load Systems, Gerardo De La Torre, Eric N. Johnson, Tansel Yucelen

Mechanical and Aerospace Engineering Faculty Research & Creative Works

This paper presents a neuropredictive trajectory generation architecture for slung load systems. The presented architecture integrates the real-time trajectory generation method with a system uncertainty identifying neural network. It is shown that the effect of system uncertainty on a model predictive control approach can be mitigated by the use of neural networks. A numerical example of an uncertain slung load system is shown to demonstrate the effectiveness of the presented framework.

Consensus Protocols For Networked Multiagent Systems With Relative Position And Neighboring Velocity Information, Gerardo De La Torre, Tansel Yucelen, Eric N. Johnson

Mechanical and Aerospace Engineering Faculty Research & Creative Works

The consensus problem appears frequently in the coordination of multiagent systems in science and engineering and involves the agreement of networked agents upon certain quantities of interest. In this paper, we focus on a new consensus protocol for networked multiagent systems. The proposed control protocol consists of a standard term capturing relative position information and a new term capturing neighboring velocity information. In particular, the addition of the latter term results in an increase of the rate of system convergence while maintaining a fixed graph structure and without increasing the maximum eigenvalue of the graph Laplacian. Furthermore, in certain cases, …

Separate-Channel Integrated Guidance And Autopilot For Automatic Path-Following, Takeshi Yamasaki, S. N. Balakrishnan, Hiroyuki Takano

Mechanical and Aerospace Engineering Faculty Research & Creative Works

An integrated guidance and autopilot scheme for a path-following uninhabited aerial vehicle is presented in this study. A fixed-wing aircraft usually performs a bank-to-turn maneuver to change its flight direction. The novel approach presented here, however, assumes that each of the three channels of the integrated guidance and autopilot can be independently designed. This concept makes the design process simple. A virtual target moving on the prespecified path for the uninhabited aerial vehicle is introduced to facilitate the algorithm development. A first-/ second order sliding structure with a second order sliding mode and a high-order sliding mode differentiator for the …

Comparison Of In Vivo Human Knee Joint Kinematics Using Axodes, Jacob Hipps

LSU Master's Theses

The human knee is of particular interest because of its importance in mobility. Pain and stability can be directly related to the motion, or kinematics, of the knee. Many studies have been conducted to quantify human knee kinematics, both in vitro and in vivo. One of the inherent issues with in vivo, skin mounted measurement systems is that they do not account for soft tissue artifact. Compensation for soft tissue artifact has been a difficult challenge for skin mounted tracking systems and has not yet been achieved. Therefore, bone mounted skeletal pins were chosen as the method of gathering kinematic …

Ionization In Diesel Combustion For On-Board Diagnostics And Engine Control, Tamer Hassan Badawy

Wayne State University Dissertations

Diesel engines have been known for their high thermal efficiency and specific power output, but there is concern about engine-out NOx and particulate matter emissions. To meet the current emission standards, advanced diesel engines are fitted with electronically controlled fuel injection systems and sophisticated and expensive after-treatment devices. Further improvements are still needed to meet future goals in better fuel economy and the more stringent emission standards. In order to meet these goals, there is a need for the control of the combustion process to reduce engine-out emissions in real-time and reduce the demand on the after-treatment devices. This requires …

Comprehensive Study Of The Dye Sensitized Solar Cell, Gregory Lewis Vick

LSU Master's Theses

A complete electrical model of the dye-sensitized solar cell has been presented. This model relates the material parameters of the cell to the cell’s performance. The full model is reduced to an Idealized form and simulated to find an idealistic power curve or current (I) – voltage (V) curve. The operating parameters of reflectivity, temperature, reverse saturation current and ideality factor are investigated. A sensitivity analysis is completed to determine what parameters have a dominating influence on the overall cell performance. It was found, for the ideal case of the dye sensitized solar cell, that the factors of absorptivity, temperature, …

Numerical Evaluation And Analysis Of The Adhesion Phenomena In Thermal Barrier Coating Systems Through Bio-Mimicking Plasma Process, Naser Imran Hossain

LSU Master's Theses

Thermal Barrier Coatings or TBCs when abbreviated are an imperative part of the thermal protection system of expensive equipment and machinery in the automobile and aeronautics industry. They provide protection to expensive alloy materials upto a temperature of 2700° C without expensive metallurgical additions. Unfortunately, the problem of coating adhesion has plagued the TBC field for years, leading to catastrophic failures in critical TBC systems. Efforts to chemically improve bond strength has not been entirely successful, so the only other efficient way to do this would be some kind of mechanical interlocking that occurs at micro/nano scales. This research work …

Asme District F Ectc Proceedings / Early Career Technical Journal (Front Matter), Asme Ectc Coordinating Committee

Early Career Technical Journal (ECTJ)

Proceedings of the ASME District F Early Career Technical Conference, November 2-3, 2013. School of Engineering, University of Alabama at Birmingham, Birmingham, Alabama

pp. i-xiv

Section 1: Bio-Medical/Bioengineering, Asme Ectc Coordinating Committee

Early Career Technical Journal (ECTJ)

Proceedings of the ASME District F Early Career Technical Conference, November 2-3, 2013. School of Engineering, University of Alabama at Birmingham, Birmingham, Alabama

pp. 1-38

Section 2: Materials, Asme Ectc Coordinating Committee

Early Career Technical Journal (ECTJ)

Proceedings of the ASME District F Early Career Technical Conference, November 2-3, 2013. School of Engineering, University of Alabama at Birmingham, Birmingham, Alabama

pp. 39-86

Section 4: Energy, Asme Ectc Coordinating Committee

Early Career Technical Journal (ECTJ)

Proceedings of the ASME District F Early Career Technical Conference, November 2-3, 2013. School of Engineering, University of Alabama at Birmingham, Birmingham, Alabama

pp. 133-152

Section 5: Numerical Methods, Asme Ectc Coordinating Committee

Early Career Technical Journal (ECTJ)

Proceedings of the ASME District F Early Career Technical Conference, November 2-3, 2013. School of Engineering, University of Alabama at Birmingham, Birmingham, Alabama

pp. 153-190

Section 6: Fluids Engineering, Asme Ectc Coordinating Committee

Early Career Technical Journal (ECTJ)

Proceedings of the ASME District F Early Career Technical Conference, November 2-3, 2013. School of Engineering, University of Alabama at Birmingham, Birmingham, Alabama

pp. 191-222

Section 7: Design & Manufacturing, Asme Ectc Coordinating Committee

Early Career Technical Journal (ECTJ)

Proceedings of the ASME District F Early Career Technical Conference, November 2-3, 2013. School of Engineering, University of Alabama at Birmingham, Birmingham, Alabama

pp. 223-256

Section 9: Miscelleneous, Asme Ectc Coordinating Committee

Early Career Technical Journal (ECTJ)

Proceedings of the ASME District F Early Career Technical Conference, November 2-3, 2013. School of Engineering, University of Alabama at Birmingham, Birmingham, Alabama

pp. 287-323

Non-Invasive Evaluation Of Energy Loss In The Pulmonary Arteries Using 4d Phase Contrast Mri Measurement, Namheon Lee, Michael D. Taylor, Kan N. Hor, Rupak K. Banerjee

Early Career Technical Journal (ECTJ)

Proceedings of the ASME District F Early Career Technical Conference, November 2-3, 2013. School of Engineering, University of Alabama at Birmingham, Birmingham, Alabama

Section 1: Bio-Medical/Bioengineering; pp. 3-6