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Articles 1 - 9 of 9
Full-Text Articles in Mechanical Engineering
Modeling Vibration Stiffness: An Analytical Extension Of Hertzian Theory For Angular Contact Bearings With A Thin Viscoelastic Coating, Davis R. Burton
Modeling Vibration Stiffness: An Analytical Extension Of Hertzian Theory For Angular Contact Bearings With A Thin Viscoelastic Coating, Davis R. Burton
Honors Theses
This thesis considers the novel angular contact rolling-element bearings proposed by NASA’s Glenn Research Center, which are coated with a thin solid lubricant that exhibits viscoelastic behavior. Current analytical models for the dynamic stiffness matrix of angular contact bearings, critical for vibration analysis, lack the ability to model the effects of a solid coating, as well as the time dependencies inherent in viscoelastic theory. The author first presents an overview of the stiffness matrix derivation, followed by a treatment of the underlying Hertzian contact theory. An analytical extension of this theory is proposed which accounts for a thin elastic layer …
Parametric Design Of Flywheel For An Electric Punch Press, Prashant Dhakal
Parametric Design Of Flywheel For An Electric Punch Press, Prashant Dhakal
Honors Theses
Almost all designs start with a design requirement. These may be weight, volume, clearance, and even custom calculations. Finding a solution that meets these requirements often involves tedious and time-consuming iterations. Once the solution has been found, the design must be optimized to find the best possible solution. Finding the ‘best possible design’ requires substantial time and effort dedicated to iterating and analyzing the potential model solutions. This is where Parametric design comes into play. The Parametric design aids in specifying the key parameters of the design and makes changes interactively, with the model updating automatically. The purpose of this …
Mathematical Modeling Of A Variable Mass Rocket’S Dynamics Using The Differential Transform Method, Ashwyn Sam
Mathematical Modeling Of A Variable Mass Rocket’S Dynamics Using The Differential Transform Method, Ashwyn Sam
Honors Theses
In this paper, the mathematical modelling of a rocket with varying mass is investigated to construct a function that can describe the velocity and position of the rocket as a function of time. This research is geared more towards small scale rockets where the nonlinear drag term is of great interest to the underlying dynamics of the rocket. A simple force balance on the rocket using Newton’s second law of motion yields a Riccati differential equation for which the solution yields the velocity of the rocket at any given time. This solution can then be integrated with respect to time …
Optimization Of Superhydrophobic Surface Production Using Ambient-Dried Silica-Based Aerogels, Elizabeth Donlon
Optimization Of Superhydrophobic Surface Production Using Ambient-Dried Silica-Based Aerogels, Elizabeth Donlon
Honors Theses
Superhydrophobic surfaces exhibit particular properties that make them functional in various anti-sticking, anti-contamination, self-cleaning and drag reduction applications. Though such surfaces are found in nature - most notably the lotus leaf - they are difficult to produce. There are numerous methods and techniques for fabricating superhydrophobic surfaces. One such method is the sol-gel method, in which aerogel, a highly porous and lightweight material that can be made hydrophobic or superhydrophobic, is coated onto a surface. The purpose of this project is to devise a simple and repeatable procedure for making hydrophobic silica aerogel coatings that can be used for drag …
Gasoline Confined In Nano-Porous Media, Matthew Giso
Gasoline Confined In Nano-Porous Media, Matthew Giso
Honors Theses
The heat of combustion was determined for gasoline confined in nano-porous media of differing pore size by bomb calorimetry. The heat of combustion of the confined fuels was comparable to that of bulk within the experimental uncertainty. This suggests that all of the confined fuel burns without any flame quenching and no chemical interactions at the interface between pore walls and fuel mitigate combustion.
Heat Of Fusion Of Primary Alcohol Confined In Nanopores, Harrisonn Griffin
Heat Of Fusion Of Primary Alcohol Confined In Nanopores, Harrisonn Griffin
Honors Theses
Melting behavior of physically confined 1-decanol in nano porous silica was probed using a Differential Scanning Calorimeter (DSC). In agreement with the Gibbs-Thomson prediction, we observe that the melting temperature of the confined 1-decanol scales inversely with the physical size of the pores. Contrary to the assumption used in developing the Gibbs-Thomson equation, however, the apparent heat of fusion decreases as the pore size decreases. Previously, several models have been proposed where interfacial layers of molecules do not participate in the phase transition and thereby would not contribute to the heat of fusion. While these could reconcile the seeming contradiction, …
Kinetic Modeling Of Catalytic Aerogels, Yi Cao
Kinetic Modeling Of Catalytic Aerogels, Yi Cao
Honors Theses
As pollution becomes an increasing concern globally, strict regulations have been set on vehicle pollutant emissions. The three-way catalytic converter is capable of converting toxic emissions such as carbon monoxide, unburned hydrocarbons and nitrogen oxides to less hazardous waste such as carbon dioxide, water, and nitrogen. Current catalysts employ platinum group metals, which are expensive and environmentally damaging to mine. Catalytically-active aerogels such as Co-Al, Cu-Al and V-Al aerogels have shown promise as alternatives to these metals. The work presented here adapts and extends a global kinetic model which predicts the conversion of hydrocarbons and carbon monoxide on platinum catalyst …
Looking For Small Changes In Heat Capacity Using A Differential Scanning Calorimeter, Will Linthicum
Looking For Small Changes In Heat Capacity Using A Differential Scanning Calorimeter, Will Linthicum
Honors Theses
One of the major difficulties in development of renewable energy is the lack of an adequate and economical means of energy storage. In the case of concentrated solar power a large mass of thermal fluid is required to store a reasonable amount of energy. This is primarily because the fluids tend to have a low specific heat capacity. Formulating composites of these fluids can enhance their specific heat capacity and avails opportunities to make concentrated solar power more attractive. In most cases, the specific heat capacity of composite materials is a weighted average of the individual component heat capacities. This, …
Manual Rubber Sandal Press For Loisaba Kenya, Bridget N. Little
Manual Rubber Sandal Press For Loisaba Kenya, Bridget N. Little
Honors Theses
The goal of this project was to develop an inexpensive manual cutting machine to cut sandals out of recycled tires and industrial belt allowing poor Kenya villages to produce their own sandals that are durable enough to survive the rough terrain. In Kenya 56 percent of the population live in poverty, surviving on less than a dollar a day. Walking is the main mode of transportation and the majority of Kenyans can only afford second hand shoes that wear out easily on the unpaved roads. In developing this machine the goal was to make the machine affordable for a company …