Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 24 for “"coefficient of restitution"”.
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Investigating the coefficient of restitution of major league baseballs
In the middle of the 2015 Major League Baseball season there was a sudden increase in home run rate. Such a sudden league-wide change is difficult to explain, and many baseball pundits suggested that a "juiced" or altered baseball was the culprit. In this thesis, large scale coefficient of …
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Technique for Measuring the Coefficient of Restitution for Microparticle Sand Impacts at High Temperature for Turbomachinery Applications
… deposition in gas turbine engines are functions of particle/wall interactions and the Coefficient of Restitution (COR) is a fundamental property of these interactions. COR depends on impact velocity, angle of impact, temperature, particle composition, and wall material. In the first study, a …
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Advancements of Particle-Surface Interaction Studies through Novel Measurement Technique Development and Engineering Modelling
Turbomachinery operating on aircraft are often exposed to dusty or sandy environments during typical service. Engines on commercial and military flights operating in desert regions such as the Middle East or even Phoenix, Arizona can become severely damaged by ingesting dirt, grit, sand, and dust. …
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Investigation Into Snap Loading of Cables Used in Moored Breakwaters
… motion. Energy is dissipated through the use of a coefficient of restitution applied when a mooring line becomes taut (i.e., reaches its natural length). The mooring line is modeled as an inextensible cable with no axial or bending resistance when slack. Snap loading arises when a mooring line …
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Modeling and Validation of Tension-Element Based Mechanisms for Golf Ball-Club Impact
… feasibility and performance benefits of the tension-element concept in golf club heads; however, higher fidelity models needed to be created and validated for this concept. There is a need for more accurate models for this concept to further investigate its performance benefits. …
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Unsupervised learning of latent physical properties using perception-prediction networks
… for the completely unsupervised learning of latent object properties from their interactions: the perception-prediction network (PPN). Consisting of a perception module that extracts representations of latent object properties and a prediction module that uses those extracted properties to …
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Effect of Temperature on Microparticle Rebound Characteristics at Constant Impact Velocity
… Particles can accelerate the deterioration of an engine and reduce the engine’s service life. Understanding particle interactions with the materials used in gas turbines, at representative engine conditions, can improve the design and development of turbomachinery operating in particle laden …
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Probing the Ability of Flexible Hydrogels to Protect Fragile Objects
Hydrogels are networks of polymer chains that are swollen in water. In recent years, several routes have been devised to make hydrogels that are flexible and bendable. This thesis investigates whether such flexible gels can be wrapped around brittle or fragile objects (such as an egg or a fruit) …
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An Approach to Concept Development for Compliant Mechanisms Possessing High Coefficients of Restitution
The design of structures and mechanisms subject to impact loading has historically involved designing in such a way as to minimize damage induced by the impact. This has historically been accomplished by absorbing and dissipating the energy of the impact. However, in some applications it is …
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The Application of Flexible Structures into Carrier-Based Aircraft to Dissipate Landing Energies
… that they must maintain as a consequence of the extremely short runway and shallow landing angle of attack. This creates a need for structural rigidity to counteract the forces that land-based aircraft never experience. This is not ideal if it otherwise limits the performance and flying …
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Analytical and experimental investigations of ships impact interaction with one-sided barrier
<p>This study deals with impact interaction of ships with one-sided ice barrier during roll dynamics. An analytical model of ship roll motion interacting with ice is developed based on Zhuravlev and Ivanov non-smooth coordinate transformations. These transformations have the advantage of converting …
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Balancing and hopping motion control algorithms for an under-actuated robot
The main contribution of this thesis is a new and simple angular momentum based control algorithm for balancing an under-actuated planar robot. The proposed controller is able to stabilize the robot at any unstable balanced configuration and to control the robot to follow motion trajectory …
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Balancing and hopping motion control algorithms for an under-actuated robot
The main contribution of this thesis is a new and simple angular momentum based control algorithm for balancing an under-actuated planar robot. The proposed controller is able to stabilize the robot at any unstable balanced configuration and to control the robot to follow motion trajectory …
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Dynamic and quasi-static contact and scratch analysis of micro-nanoscale thin solid films with application to magnetic storage hard disk drives
With current demand for decreased size of micro/nanoscale systems, coupled with increased mobility, critical understanding of the ensuing contact or impact related behavior of thin solid films used in these systems is of paramount importance for improved design and reliability. In modern …
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Rotary kiln transport phenomena: a study of the bed motion and heat transfer
Thermal processing of materials in rotary kilns involves heat transfer from the freeboard to the boundary surfaces of bed material and the distribution of this thermal energy within the granular bed. Although the former has been reasonably well characterized, the latter has not, mainly because of …
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Advancing Rockfall Hazard Assessment through Data-Driven Modelling Based on Laboratory-Scale Experiments
Understanding the dynamics of rockfalls is critical for predicting hazards and mitigating risks in both natural and engineered environments. This research investigates the relationship between rock shape, release angle, and rockfall behavior, combining experimental analysis with machine learning …
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Numerical and experimental investigation of dry particle coating
… to the widely reported experimental studies of the dry particle coating, the theoretical modeling of such processes is found to be less comprehensive. The work presented in this thesis is an attempt to fill this gap. The first part of the dissertation aims at the numerical investigation of …
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Studies of the Human Head from Neonate to Adult: An Inertial, Geometrical and Structural Analysis with Comparisons to the ATD Head
… injury is a very costly problem, both in terms of morbidity/mortality and direct medical costs. In fact, it is the leading cause of death and disability for those in the United States under age 18-years-old. Currently, head injury in children ages newborn to 19-years-old is responsible for 7500 …
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Experimental Investigation of Temperature Effects on Microparticle Sand Rebound Characteristics at Gas Turbine Representative Conditions
… to engine components and reduce the service life of the engine. Particle ingestion causes the erosion of metal blades and vanes, and, if the firing temperature is hot enough, deposition of molten particles in the hot sections of the engine. Both deposition and erosion phenomena can severely reduce …
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A Computational Framework for Fluid-Thermal Coupling of Particle Deposits
… allows insight into the coupled behavior of sand deposits at high temperatures with the flow, which has not been available previously. The coupling is done by using a CFD-DEM framework in which a physics based collision model is used to predict the post-collision …
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