Engineering Commons^™

Plasma Test On Industrial Diamond Powder In Hydrogen And Air For Fracture Strength Study, Rohit Asuri Sudharshana Asuri Sudharshana Chary

UNLV Theses, Dissertations, Professional Papers, and Capstones

Diamonds are the most precious material all over the world. Ever since their discovery, the desire for natural diamonds has been great; recently, the demand has steeply increased, leading to scarcity. For example, in 2010, diamonds worth $50 billion were marketed. This increased demand has led to discovering alternative sources to replace diamonds. The diamond, being the hardest material on earth, could be replaced with no other material except another diamond. Thus, the industrial or synthetic diamond was invented. Because of extreme hardness is one of diamond's properties, diamonds are used in cutting operations. The fracture strength of diamond is …

Basic Research On The Characteristics Of A Constricted Pulsed Glow Discharge, Sean Daniel Andersen

UNLV Theses, Dissertations, Professional Papers, and Capstones

In certain plasma discharge experiments, it has been observed that under specific conditions a plasma glow discharge column tends to seek the central location of the discharge electrodes away from the electrode edges and chamber walls. Further, the column appears to have the properties of a stabilized equilibrium plasma pinch in a glow (non-arc-like) state. This is unusual since, normally field enhancements occur on edges resulting in arc-like discharge breakdown. Also, the column of plasma that protrudes from the anode emits highly intense, non-uniform light that is uncharacteristically bright for a glow discharge.

The main purpose of this thesis is …

Electrospun Polycaprolactone Nanofiber Scaffolds For Tissue Engineering, Andreas Haukas

Graduate Theses and Dissertations

Stem cell and tissue engineering offer us with a unique opportunity to research and develop new therapies for treating various diseases that are otherwise incurable using traditional medicines. However, development of these new therapies replies upon the establishment of in vitro cell culture and differentiation systems that mimic in vivo microenvironments required for cell-cell and cell-ECM interaction. The development of these cell culture systems depends upon the identification of appropriate biomaterials and cell sources. Biomaterials should be carefully selected and fabricated into scaffolds for supporting cell growth and differentiation. In this study, we explored the fabrication of 3D electrospun nanofiber …

Use Of Ultra High Vacuum Plasma Enhanced Chemical Vapor Deposition For Graphene Fabrication, Shannen Adcock

Graduate Theses and Dissertations

Graphene, what some are terming the "new silicon", has the possibility of revolutionizing technology through nanoscale design processes. Fabrication of graphene for device processing is limited largely by the temperatures used in conventional deposition. High temperatures are detrimental to device design where many different materials may be present. For this reason, graphene synthesis at low temperatures using plasma-enhanced chemical vapor deposition is the subject of much research. In this thesis, a tool for ultra-high vacuum plasma-enhanced chemical vapor deposition (UHV-PECVD) and accompanying subsystems, such as control systems and alarms, are designed and implemented to be used in future graphene growths. …

Modeling And Measuring The Characteristics Of An Inductively Coupled Plasma Antenna For A Micro-Propulsion System, Sonya Mary Christensen

Boise State University Theses and Dissertations

An ion thruster for satellites on the order of 10-50 kg in mass is currently under development. The thruster uses an Inductively Coupled Plasma (ICP) generated by a flat spiral antenna fabricated using the Low Temperature Co-Fired Ceramic (LTCC) materials system. The antenna operating frequency range (600 MHz to 1 GHz) in LTCC (ε_r=7.8) results in a wavelength on the same order of magnitude as the total length of conductor in the antenna. This condition provides some interesting antenna electric and magnetic field characteristics. The antenna has been modeled using COMSOL Multiphysics® Simulation Software. By changing the geometry …

Multi-Term Approximation To The Boltzmann Transport Equation For Electron Energy Distribution Functions In Nitrogen, Yue Feng

Electrical & Computer Engineering Theses & Dissertations

Plasma is currently a hot topic and it has many significant applications due to its composition of both positively and negatively charged particles. The energy distribution function is important in plasma science since it characterizes the ability of the plasma to affect chemical reactions, affect physical outcomes, and drive various applications. The Boltzmann Transport Equation is an important kinetic equation that provides an accurate basis for characterizing the distribution function—both in energy and space.

This dissertation research proposes a multi-term approximation to solve the Boltzmann Transport Equation by treating the relaxation process using an expansion of the electron distribution function …