Thesis (M.S.)--Oregon State University, 2011. / Printout. Includes bibliographical references (leaves 106-107). Also available on the World Wide Web.

Thesis (Ph. D.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 145-146). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2008. / Printout. Includes bibliographical references (leaves 79-83). Also available on the World Wide Web.

No description available.

This thesis describes modulated methods using both voltammetric and microfluidic perturbations to study mechanisms of electrolysis reactions. The initial chapters provide an overview of applications and research development in the fields of micro-engineering and electrochemistry, including microfabrication methodology, electrochemical detection techniques and analysis methods. Some typical electrochemical reactions have been studied for different kinds of industrial applications. Also hydrodynamic modulation methods have been investigated. The result chapters begin in Chapter 3 with detailed investigation of various electrochemical reactions by using cyclic voltammetry (CV) and large amplitude Fourier transformed alternating current voltammetry (FTACV) under microfluidic conditions. Single electron transfer reactions with different kinetics were studied first by using potassium ferrocyanide and ferrocenecarboxylic acid (FCA). Dual electron transfer reactions with different pathways were investigated by using 2,5-dihydroxybenzoic acid for one step oxidation and N,N,N',N'-tetramethyl-para-phenylene-diamine (TMPD) for two consecutive one-electron step oxidation. An irreversible reaction was explored by using borohydride solution. Examples of homogeneous reaction mechanisms were studied by using the combinations of Fe(CN)64-/L-cysteine or TMPD/ascorbic acid. The current response of all the electrolysis reactions except single electron transfer reactions was first reported under microfluidic conditions with FTACV, which has shown sensitive with the change of volume flow rates and the substrate concentrations when homogeneous reactions are involved. The linear relationships between peak current and volume flow rates or substrate concentrations can be obtained in every harmonic component. In chapter 4, the modulated technique was applied to microfluidic hydrodynamic systems. A range of electrolysis mechanisms including single electron transfer reactions, dual electron transfer reactions, irreversible reaction and homogeneous reactions were studied under hydrodynamic modulated conditions. The system showed rapid response with the change of volume flow rates during one measurement. The linear relationships between peak current and flow rates, as well as substrate concentrations, can be obtained simultaneously in one scan, which reveals a promising approach to get more information in a short-time measurement. Chapter 5 demonstrated a new protocol by forcing an oscillation of the electrochemical active solution flowing. Analysis of transition time and its effect on limiting current are presented to begin exploration of this new tool for supporting researchers on understanding redox mechanisms. A short simulated study was carried out to help better understand the mechanism under different hydrodynamic conditions.

Chemical microreactors offer opportunities for portable power generation, on-site waste remediation and point-of-use chemical synthesis. Much of the existing development of microreactor devices involves silicon-based microfabrication techniques. It is recognized that new refractory materials are important to realizing high-temperature microreactors. Requirements of these materials include high-temperature resistance, chemical inertness and low-cost microfabrication. Advances in multilayer ceramics hold promise for the fabrication of microreactor structures from ceramic tape. Problems include creep, moderate levels of densification, and volumetric shrinkage, all of which can lead to dimensional instability. Intermetallics are another class of refractory materials which may hold some promise for high-temperature microreactor development. In this paper, a new method of forming microchannel arrays from thin layers of intermetallics is demonstrated. This method has the advantage of eliminating volumetric shrinkage due to binder removal. Various iterations of NiAl intermetallic conversion and bonding are presented. Results show that the NiAl system may be suitable as a substrate for microchannel reactor designs. / Graduation date: 2002

Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 79-81). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 104-110). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 97-101). Also available on the World Wide Web.

Thesis (M.S.)--Oregon State University, 2010. / Printout. Includes bibliographical references (leaves 107-110). Also available on the World Wide Web.