Physical Sciences and Mathematics Commons^™

Molecular Processes In Astrophysics: Calculations Of H + H2 Excitation, De-Excitation, And Cooling, Matthew Kelley

UNLV Theses, Dissertations, Professional Papers, and Capstones

The implications of H+H2 cooling in astrophysics is important to several applications. One of the most significant and pure applications is its role in cooling in the early universe. Other applications would include molecular dynamics in nebulae and their collapse into stars and astrophysical shocks. Shortly after the big bang, the universe was a hot primordial gas of photons, electrons, and nuclei among other ingredients. By far the most dominant nuclei in the early universe was hydrogen. In fact, in the early universe the matter density was 90 percent hydrogen and only 10 percent helium with small amounts of lithium …

Surface Structuring Strategies For Micro-Cantilever Sensing Platforms And Applications For Hydrogen Related Issues, James F. Patton

Doctoral Dissertations

Recent developments in microelectro-mechanical systems have enabled the exploration of transduction modes that involve mechanical energy and are based primarily on mechanical phenomena. As a result an innovative family of chemical and biological sensors has emerged which utilize a transducer in the form of microcantilevers (MCs). MCs offer greater sensitivity than comparable mass-responding sensors due in large part to their small dimension. These low cost devices can be deployed for remote testing, providing real-time information for the analyst. An additional advantage is the ability to employ MCs in an arrayed fashion adding a unique selectivity not available to many sensing …

Synthesis, Characterization, And Evaluation Of A Heat Stabilizing Siloxane, Joel D. Kennard

Master's Theses and Doctoral Dissertations

Siloxanes, renowned for their heat resistance and release properties, are prone to oxidize above 200°C. The goal herein is to increase siloxane bath life used in fuser roll applications at temperatures above 200°C, yielding faster production, less waste, and cost savings by keeping the bath viscosity stable through prevention of thermal degradation.

The methods detailed herein react a hydrosiloxane with an amino functional alcohol (4-(phenylamino)-phenol). The alcoholysis (or dehydrogenative coupling) moves forward with the removal of hydrogen and formation of the desired product (Scheme 1). Reactions were conducted on both NMR scale and lab scale.

The results of the synthesis …

The Behavior Of Cerium Oxide Nanoparticles In Polymer Electrolyte Membranes In Ex-Situ And In-Situ Fuel Cell Durability Tests, Benjamin Pearman

Electronic Theses and Dissertations

Fuel cells are known for their high efficiency and have the potential to become a major technology for producing clean energy, especially when the fuel, e.g. hydrogen, is produced from renewable energy sources such as wind or solar. Currently, the two main obstacles to wide-spread commercialization are their high cost and the short operational lifetime of certain components. Polymer electrolyte membrane (PEM) fuel cells have been a focus of attention in recent years, due to their use of hydrogen as a fuel, their comparatively low operating temperature and flexibility for use in both stationary and portable (automotive) applications. Perfluorosulfonic acid …