Mechanical Engineering Commons^™

Depressurization Characteristics Of Steam-Based Reciprocating Vacuum Pump, Hongling Deng

Dissertations

This dissertation introduces a novel vacuum technology that leverages low-pressure saturated steam and cooling-controlled condensation, offering an efficient way to utilize low-grade thermal energy sources like waste heat, steam, or solar energy. At the heart of this technology is a unique duo-chamber vacuum pump system, featuring a reciprocating piston and a heat-conductive wall, designed to generate a vacuum through steam-condensation and cooling processes.

The core of this research lies in developing and validating mechanistic models for the steam-condensation depressurization process, a complex phenomenon involving phase change and transport mechanisms. Prior to this work, these mechanisms were not sufficiently modeled or …

On The Selection Of A Good Shape Parameter For Rbf Approximation And Its Application For Solving Pdes, Lei-Hsin Kuo

Dissertations

Meshless methods utilizing Radial Basis Functions~(RBFs) are a numerical method that require no mesh connections within the computational domain. They are useful for solving numerous real-world engineering problems. Over the past decades, after the 1970s, several RBFs have been developed and successfully applied to recover unknown functions and to solve Partial Differential Equations (PDEs).
However, some RBFs, such as Multiquadratic (MQ), Gaussian (GA), and Matern functions, contain a free variable, the shape parameter, c. Because c exerts a strong influence on the accuracy of numerical solutions, much effort has been devoted to developing methods for determining shape parameters which provide …

Development Of Energy Absorbing Laminated Fiberglass Composites Using Electrospun Glass Nanofibers, Evan Kimbro

Dissertations

The ability to predict failure of composite laminates due to delaminations is critical because of its subsurface nature. Traditional strengthening methods such as stitching and Z-pinning, while improving interlaminar properties in woven composites, lead to a reduction of the in-plane properties. Electrospun non-woven sheets of nanofibrous mat applied at interfacial regions offer an option to traditional treatments. Applications where protrusion energy must be dissipated completely would benefit the most from the use of the electrospinning treatment. Examples are bullet proof vests and vehicle armor. Penetration of a projectile through a composite material may be avoided by creating more energy absorbent …