I. Fundamental practicum--fluorescence lifetime imaging: An approach for fuel equivalence ratio imaging. II. Industrial practicum--the interactions between ionic surfactants and divalent cations. III. Apprenticeship practicum--the relaxed and spectroscopi

The local fuel equivalence ratio, a normalized ratio of the fuel and oxygen concentrations, is one of the most important parameters used to characterize combustion systems. This paper describes dopants and apparatus which can be used for PLIF imaging of the equivalence ratio. In addition to conventional intensity imaging, the lifetime imaging technique described here introduces additional data which should allow the equivalence ratio to be determined in real time in a two-dimensional slice of a fuel spray.;The lifetime imaging methods require the two 2-D detectors sequential gating on during the fluorescence decay. The two integrated intensities as measured by the two detectors are processed to yield a lifetime image. Proof-of-concept experiments indicate that lifetimes ranging from 5 to 50 nanoseconds can be imaged with good accuracy. The requirements for fluorescent dopants are also discussed.;The industrial practicum report, entitled "The Interactions Between Ionic Surfactants and Divalent Cations" investigates surfactant/divalent ion interactions which occur in the systems composed of ionic surfactant, oil and brine. Based on electrical double layer theory, two models were developed to study the interactions. One model describes the cation-exchange properties of the surfactants. The other model characterizes the optimal salinity changes in the presence of divalent cations. The cation-exchange model qualitatively predicts the effects of brine salinity, surfactant hydrophile length, surface charge density, and temperature on cation-exchange. The optimal salinity model describes the linear relationship between the optimal salinity and the fraction of divalent cations associated with the surfactant. The optimal salinity model also shows how the structure of surfactant affects the relationship between associated divalent cations and optimal salinity. The models are very usable in understanding the phase behavior of ionic surfactant with reservoir oil and brine during the enhanced oil recovery by micellar-polymer flooding.;In this report, entitled "The Relaxed and Spectroscopic Energies of Olefin Triplets", the relaxed energies and lifetimes of a series of olefin triplets have been determined by time-resolved photoacoustic calorimetry using a novel cell configuration which allows improved precision. The planar triplet energies of a number of olefins were measured by oxygen and heavy-atom perturbation methods. For styrene triplets, the difference between the relaxed and planar triplet energies varies from 0 to 10 kcal/mole depending on the degree of twisting allowed. Stilbene triplets show a rather flat potential surface. New Benson group equivalents for a number of free radical additivities derived from literature values of heats of formation of radical are tabulated. The energies of acyclic, fully relaxed triplets are in excellent agreement with the values calculated by the Benson method using the new radical group values and the assumption that the triplet is satisfactorily modeled as a "1,2-biradical.".