Open Access. Powered by Scholars. Published by Universities.®
Physical Sciences and Mathematics
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
- Keyword
-
- Additive manufacturing (1)
- Aggregation (1)
- Alpha Irradiation (1)
- Amorphous Boron Carbide (1)
- Autonomous agents (1)
-
- Biomimetics (1)
- Bistable mechanisms (1)
- CTRNN (1)
- Cooperative robots (1)
- Corrosion (1)
- DLP (1)
- Damage mechanics (1)
- Decision making (1)
- Defect (1)
- Dip coating (1)
- Double resonance excitation (1)
- Electrical Characterization (1)
- Fast solvers (1)
- Fluorescence (1)
- Fracture (1)
- HAp (1)
- Laser shock peening (1)
- Lifetime (1)
- MEMS (1)
- Metamaterials (1)
- Modular robot (1)
- Neuromorphic computing (1)
- Neutron Detection (1)
- Neutron Irradiation (1)
- Nonlinear wave propagation (1)
Articles 1 - 10 of 10
Full-Text Articles in Engineering
Sliding Markov Decision Processes For Dynamic Task Planning On Uncrewed Aerial Vehicles, Trent Wiens
Sliding Markov Decision Processes For Dynamic Task Planning On Uncrewed Aerial Vehicles, Trent Wiens
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
Mission and flight planning problems for uncrewed aircraft systems (UASs) are typically large and complex in space and computational requirements. With enough time and computing resources, some of these problems may be solvable offline and then executed during flight. In dynamic or uncertain environments, however, the mission may require online adaptation and replanning. In this work, we will discuss methods of creating MDPs for online applications, and a method of using a sliding resolution and receding horizon approach to build and solve Markov Decision Processes (MDPs) in practical planing applications for UASs. In this strategy, called a Sliding Markov Decision …
Characterization Of Interlayer Laser Shock Peening During Fused Filament Fabrication Of Polylactic Acid (Pla), Fabien Denise
Characterization Of Interlayer Laser Shock Peening During Fused Filament Fabrication Of Polylactic Acid (Pla), Fabien Denise
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
The field of additive manufacturing (AM) has gained a significant amount of popularity due to the increasing need for more sustainable manufacturing techniques and the adaptive development of complex product geometries. The problem is that AM parts routinely exhibit flaws or weaknesses that affect functionality or performance. Over the years, surface treatments have been developed to compensate certain flaws or weaknesses in manufactured products. Combining surface treatments with the modularity of additive manufacturing could lead to more adaptable and creative improvements of product functions in the future. The current work evaluates the feasibility of pursuing a new research axis in …
Experimental Analysis Of Nonlinear Wave Propagation In Bistable Mechanical Metamaterials With A Defect, Samuel R. Harre
Experimental Analysis Of Nonlinear Wave Propagation In Bistable Mechanical Metamaterials With A Defect, Samuel R. Harre
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
Mechanical metamaterials built up of compliant units can support the propagation of linear and nonlinear waves. A popular architecture consists of a one-dimensional chain of bistable elements connected by linear springs. This type of chain can support nonlinear transition waves that switch each element from one stable state to the other as they propagate along the chain. One way to manipulate the propagation of such waves is via introduction of a local inhomogeneity, i.e., a defect in the otherwise periodic chain. Recent analytical and numerical work has shown that based on its initial velocity, a transition wave may be reflected, …
Hydroxyapatite-Based Coatings On Silicon Wafers And Printed Zirconia, Antoine Chauvin
Hydroxyapatite-Based Coatings On Silicon Wafers And Printed Zirconia, Antoine Chauvin
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
Dental surgery needs a naturally attract implant design that can ensure both osseointegration and soft tissue integration. Hydroxyapatite (HAp), the main mineral constituent of dentine and tooth enamel, is commonly used as a coating component, notably for overlaying titanium– or ceramics–based implants. This thesis aims to investigate the behavior of a HAp-based coating, specifically designed to be compatible with a porous substrate. Coating layers are made by sol–gel dip coating by immersion of porous substrates made by additive manufacturing into solutions of HAp, having been mixed with polyethyleneimine (PEI), to improve the adhesion of HAp on the substrate. First, the …
Novel And Fast Peridynamic Models For Material Degradation And Failure, Siavash Jafarzadeh
Novel And Fast Peridynamic Models For Material Degradation And Failure, Siavash Jafarzadeh
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
Fracture is one of the main mechanisms of structural failure. Corroded surfaces with chemically-induced damage are, notably, potential sites for crack initiation and propagation in metals, which can lead to catastrophic failure of structures. Despite some progress in simulating fracture and damage using classical models, realistic prediction of complex damage progression and failure has been out of reach for many decades. Peridynamics (PD), a nonlocal theory introduced in 2000, opened up new avenues in modeling material degradation and failure. Existing numerical methods used to discretize PD equations, however, are quite expensive as the PD nonlocal interactions make them unaffordable for …
Machine Learning Augmentation Micro-Sensors For Smart Device Applications, Mohammad H. Hasan
Machine Learning Augmentation Micro-Sensors For Smart Device Applications, Mohammad H. Hasan
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
Novel smart technologies such as wearable devices and unconventional robotics have been enabled by advancements in semiconductor technologies, which have miniaturized the sizes of transistors and sensors. These technologies promise great improvements to public health. However, current computational paradigms are ill-suited for use in novel smart technologies as they fail to meet their strict power and size requirements. In this dissertation, we present two bio-inspired colocalized sensing-and-computing schemes performed at the sensor level: continuous-time recurrent neural networks (CTRNNs) and reservoir computers (RCs). These schemes arise from the nonlinear dynamics of micro-electro-mechanical systems (MEMS), which facilitates computing, and the inherent ability …
Electrical Characterization Of Irradiated Semiconducting Amorphous Hydrogenated Boron Carbide, George Glen Peterson
Electrical Characterization Of Irradiated Semiconducting Amorphous Hydrogenated Boron Carbide, George Glen Peterson
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
Semiconducting amorphous partially dehydrogenated boron carbide has been explored as a neutron voltaic for operation in radiation harsh environments, such as on deep space satellites/probes. A neutron voltaic device could also be used as a solid state neutron radiation detector to provide immediate alerts for radiation workers/students, as opposed to the passive dosimetry badges utilized today. Understanding how the irradiation environment effects the electrical properties of semiconducting amorphous partially dehydrogenated boron carbide is important to predicting the stability of these devices in operation. p-n heterojunction diodes were formed from the synthesis of semiconducting amorphous partially dehydrogenated boron carbide on silicon …
Formation Of Mound-Like Multiscale Surface Structures On Titanium By Femtosecond Laser Processing, Edwin Peng, Alfred Tsubaki, Craig A. Zuhlke, Ryan Bell, Meiyu Wang, Dennis R. Alexander, George Gogos, Jeffrey E. Shield
Formation Of Mound-Like Multiscale Surface Structures On Titanium By Femtosecond Laser Processing, Edwin Peng, Alfred Tsubaki, Craig A. Zuhlke, Ryan Bell, Meiyu Wang, Dennis R. Alexander, George Gogos, Jeffrey E. Shield
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
Surface Functionalization Technique • Femtosecond Laser Surface Processing (FLSP) • Utilize high power, femtosecond (10-15 s) laser pulses • Produce self-organized, multiscale surface micro/nanostructures • Diverse range of applicable substrates: semiconductors, metals, polymers, & composites
Why? • What are the different types of FLSP structures on Ti? • Physical evidence needed for FLSP formation models • Optimize FLSP of Ti for biomedical & other applications
How? • Obtain evidence of mound growth processes by examining underlying microstructure • Utilize dual beam Scanning Electron Microscope-Focused Ion Beam instrument to cross section surface structures & fabricate transmission electron microscopy samples
Towards A Sustainable Modular Robot System For Planetary Exploration, S. G. M. Hossain
Towards A Sustainable Modular Robot System For Planetary Exploration, S. G. M. Hossain
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
This thesis investigates multiple perspectives of developing an unmanned robotic system suited for planetary terrains. In this case, the unmanned system consists of unit-modular robots. This type of robot has potential to be developed and maintained as a sustainable multi-robot system while located far from direct human intervention. Some characteristics that make this possible are: the cooperation, communication and connectivity among the robot modules, flexibility of individual robot modules, capability of self-healing in the case of a failed module and the ability to generate multiple gaits by means of reconfiguration. To demonstrate the effects of high flexibility of an individual …
Near-Infrared Surface-Enhanced Fluorescence Using Silver Nanoparticles In Solution, Michael D. Furtaw
Near-Infrared Surface-Enhanced Fluorescence Using Silver Nanoparticles In Solution, Michael D. Furtaw
Department of Mechanical and Materials Engineering: Dissertations, Theses, and Student Research
Fluorescence spectroscopy is a widely used detection technology in many research and clinical assays. Further improvement to assay sensitivity may enable earlier diagnosis of disease, novel biomarker discovery, and ultimately, improved outcomes of clinical care along with reduction in costs. Near-infrared, surface-enhanced fluorescence (NIR-SEF) is a promising approach to improve assay sensitivity via simultaneous increase in signal with a reduction in background. This dissertation describes research conducted with the overall goal to determine the extent to which fluorescence in solution may be enhanced by altering specific variables involved in the formation of plasmonactive nanostructures of dye-labeled protein and silver nanoparticles …