Reaction rate oscillations during catalytic CO oxidation: A brief overview

It is not the intent here to present a comprehensive review of the dynamic behavior of the catalytic oxidation of CO. This reaction is one of the most widely studied in the field of catalysis. A review paper by Engel and Ertl has examined the basic kinetic and mechanistic aspects, and a comprehensive paper by Razon and Schmitz was recently devoted to its dynamic behavior. Those interested in further study of the subject should consult these reviews and a number of general review papers on catalytic reaction dynamics. The goal is to present a brief overview of certain interesting aspects of the dynamic behavior of this reaction and to discuss a few questions and issues, which are still the subject of study and debate

First principles-based multiparadigm, multiscale strategy for simulating complex materials processes with applications to amorphous SiC films

Progress has recently been made in developing reactive force fields to describe chemical reactions in systems too large for quantum mechanical (QM) methods. In particular, ReaxFF, a force field with parameters that are obtained solely from fitting QM reaction data, has been used to predict structures and properties of many materials. Important applications require, however, determination of the final structures produced by such complex processes as chemical vapor deposition, atomic layer deposition, and formation of ceramic films by pyrolysis of polymers. This requires the force field to properly describe the formation of other products of the process, in addition to yielding the final structure of the material. We describe a strategy for accomplishing this and present an example of its use for forming amorphous SiC films that have a wide variety of applications. Extensive reactive molecular dynamics (MD) simulations have been carried out to simulate the pyrolysis of hydridopolycarbosilane. The reaction products all agree with the experimental data. After removing the reaction products, the system is cooled down to room temperature at which it produces amorphous SiC film, for which the computed radial distribution function, x-ray diffraction pattern, and the equation of state describing the three main SiC polytypes agree with the data and with the QM calculations. Extensive MD simulations have also been carried out to compute other structural properties, as well the effective diffusivities of light gases in the amorphous SiC film

Experimental and Modeling Studies of the Combustion Characteristics of Conventional and Alternative Jet Fuels. Final Report

The objectives of this project have been to develop a comprehensive set of fundamental data regarding the combustion behavior of jet fuels and appropriately associated model fuels. Based on the fundamental study results, an auxiliary objective was to identify differentiating characteristics of molecular fuel components that can be used to explain different fuel behavior and that may ultimately be used in the planning and design of optimal fuel-production processes. The fuels studied in this project were Fischer-Tropsch (F-T) fuels and biomass-derived jet fuels that meet certain specifications of currently used jet propulsion applications. Prior to this project, there were no systematic experimental flame data available for such fuels. One of the key goals has been to generate such data, and to use this data in developing and verifying effective kinetic models. The models have then been reduced through automated means to enable multidimensional simulation of the combustion characteristics of such fuels in real combustors. Such reliable kinetic models, validated against fundamental data derived from laminar flames using idealized flow models, are key to the development and design of optimal combustors and fuels. The models provide direct information about the relative contribution of different molecular constituents to the fuel performance and can be used to assess both combustion and emissions characteristics

CAPP: A Comprehensive Preventative Program Model Addressing Alcohol Misuse Among College Freshmen

Alcohol consumption by college students in the United States has increased in quantity and frequency over the past five years. With this increase, there has come evidence of a rise in negative consequences caused by alcohol misuse. To help reduce these problems, colleges and universities nationwide have begun implementing alcohol programs for their undergraduate students. The vast majority of these programs are intervention programs for students who have previously displayed dangerous drinking habits, often seen through campus judicial violations. Research shows that preventative program models, as compared to intervention programs, provide longer lasting changes in individuals and groups. Thus, a prevention approach informs the structural foundation of this dissertation project\u27s development of a comprehensive alcohol program. The Comprehensive Alcohol Prevention Program (CAPP) integrates motivational interviewing, psychoeducation, and developmental concepts and findings in order to more effectively address the misuse of alcohol among the emerging adulthood population, and specifically with college freshmen. The emerging adult issues of exploration, experimentation, and emotional and social challenges are components of the transition to college life and to adulthood. CAPP is designed to use the concepts and strategies of motivational interviewing, and psychoeducation in a developmentally informed manner to reduce alcohol misuse in emerging adults within the first year of college. It is anticipated that this comprehensive preventative program model will facilitate the transformation of emerging adults during their transition into college life

CAPP: A Comprehensive Preventative Program Model Addressing Alcohol Misuse Among College Freshmen

Alcohol consumption by college students in the United States has increased in quantity and frequency over the past five years. With this increase, there has come evidence of a rise in negative consequences caused by alcohol misuse. To help reduce these problems, colleges and universities nationwide have begun implementing alcohol programs for their undergraduate students. The vast majority of these programs are intervention programs for students who have previously displayed dangerous drinking habits, often seen through campus judicial violations. Research shows that preventative program models, as compared to intervention programs, provide longer lasting changes in individuals and groups. Thus, a prevention approach informs the structural foundation of this dissertation project\u27s development of a comprehensive alcohol program. The Comprehensive Alcohol Prevention Program (CAPP) integrates motivational interviewing, psychoeducation, and developmental concepts and findings in order to more effectively address the misuse of alcohol among the emerging adulthood population, and specifically with college freshmen. The emerging adult issues of exploration, experimentation, and emotional and social challenges are components of the transition to college life and to adulthood. CAPP is designed to use the concepts and strategies of motivational interviewing, and psychoeducation in a developmentally informed manner to reduce alcohol misuse in emerging adults within the first year of college. It is anticipated that this comprehensive preventative program model will facilitate the transformation of emerging adults during their transition into college life

Sculpting oscillators with light within a nonlinear quantum fluid

Seeing macroscopic quantum states directly remains an elusive goal. Particles with boson symmetry can condense into such quantum fluids producing rich physical phenomena as well as proven potential for interferometric devices [1-10]. However direct imaging of such quantum states is only fleetingly possible in high-vacuum ultracold atomic condensates, and not in superconductors. Recent condensation of solid state polariton quasiparticles, built from mixing semiconductor excitons with microcavity photons, offers monolithic devices capable of supporting room temperature quantum states [11-14] that exhibit superfluid behaviour [15,16]. Here we use microcavities on a semiconductor chip supporting two-dimensional polariton condensates to directly visualise the formation of a spontaneously oscillating quantum fluid. This system is created on the fly by injecting polaritons at two or more spatially-separated pump spots. Although oscillating at tuneable THz-scale frequencies, a simple optical microscope can be used to directly image their stable archetypal quantum oscillator wavefunctions in real space. The self-repulsion of polaritons provides a solid state quasiparticle that is so nonlinear as to modify its own potential. Interference in time and space reveals the condensate wavepackets arise from non-equilibrium solitons. Control of such polariton condensate wavepackets demonstrates great potential for integrated semiconductor-based condensate devices.Comment: accepted in Nature Physic