The mechanism of carbon coupling reactions is traditionally represented in a very broad schematic. This thesis seeks to explore the mechanism of these reactions by focusing on Heck olefination. The Heck reaction has become a powerful tool in synthetic labs but the mechanism of this reaction has remained a topic of debate since the reaction's discovery. The catalytic cycle that has come to be accepted, while accurate in its own right, is not nearly as detailed as the complexity of the various stages of the Heck reaction suggest it should be. This study seeks to elucidate the nature of the oxidative addition of aryl halide to a palladium catalyst using a ligand that has been shown to have high activity in facilitating oxidative addition of aryl chlorides and bromides in other coupling reactions. This information is then compared to other studies in the field so that conclusions can be drawn about the oxidative addition. Also, selectivity studies seek to determine the nature of the migratory insertion of an olefin into the Pd-Ar bond. Again, comparison of results obtained in this study are compared to previous results so that a more definitive conclusion can be drawn about the oxidative addition.

The hydrodynamic excitation and response behavior of multi-body systems with varying degrees of coupling presents many challenges for designers of offshore structures. In this study, attention is focused upon the analysis and interpretation of experimental data obtained for an unmanned deepwater mini-Tension Leg Platform (mini-TLP) coupled to a tender barge. Each body has its own mooring system and the bodies are connected by two breast lines extending from central points on the mini-TLP to central points on the bow and stern of the tender barge. A fender system is located between the two platforms. Thus the two floating bodies are constrained to move together in surge and yaw while they are free to move independently in heave, roll and pitch with some limitations on sway. The data of the individual records are characterized using statistical moments, including skewness and kurtosis, to examine the degree of non-Gaussian behavior. Correlation analysis and cross spectral analysis are used to investigate the relationships between selected measurements such as the motion of each vessel, tensions in the mooring lines and tendons and the forces on the fenders. The analysis shows that the coupling effects reduce the mooring line and tendon tensions significantly and that the motions of the two vessels influence the line tensions and fender forces. The data distribution patterns followed by the parameters and the corresponding extreme values are also investigated.

As fabrication technology keeps advancing, many deep submicron (DSM) effects have become increasingly evident and can no longer be ignored in Very Large Scale Integration (VLSI) design. In this dissertation, we study several deep submicron problems (eg. coupling capacitance, antenna effect and delay variation) and propose optimization techniques to mitigate these DSM effects in the place-and-route stage of VLSI physical design. The place-and-route stage of physical design can be further divided into several steps: (1) Placement, (2) Global routing, (3) Layer assignment, (4) Track assignment, and (5) Detailed routing. Among them, layer/track assignment assigns major trunks of wire segments to specific layers/tracks in order to guide the underlying detailed router. In this dissertation, we have proposed techniques to handle coupling capacitance at the layer/track assignment stage, antenna effect at the layer assignment, and delay variation at the ECO (Engineering Change Order) placement stage, respectively. More specifically, at layer assignment, we have proposed an improved probabilistic model to quickly estimate the amount of coupling capacitance for timing optimization. Antenna effects are also handled at layer assignment through a linear-time tree partitioning algorithm. At the track assignment stage, timing is further optimized using a graph based technique. In addition, we have proposed a novel gate splitting methodology to reduce delay variation in the ECO placement considering spatial correlations. Experimental results on benchmark circuits showed the effectiveness of our approaches.

This paper proposed a low-cost and high-throughput method to fabricate lensed optical fibers. SU-8 Photoresist is used as the material for fabricating the proposed lens structure and is directly applied on two kinds of optical fiber tip, single mode glass fibers (O.D.=125 £gm) and plastic graded-index plastic fiber (O.D.=500 £gm), utilizing surface tension force to form a hemi-circular shape lens structure. The hemi-circular shape SU-8 lens is then electrostatically pulled to form non-spherical shape in an uniform electric field at a temperature higher than the glass temperature (Tg) of SU-8. Microlens with various radius of curvature can be easily produced by tuning the applied electric fields during the electrostatic pulling process. In addition, this study also measures the UV-Vis-NIR spectrum SU-8 photoresist to confirm the optical property of SU-8. Results indicate the SU-8 has high optical transmittance from the wavelength range of 380-1600 nm. SEM observation also indicates the fabricated SU-8 microlens has excellent surface smoothness which is essential for optical applications. A commercial optical simulation software of ZEMAX® is used to predict the light path of the fabricated lensed fiber. The numerical results show good agreement with the experimental test obtained by projecting laser light into a diluted fluorescence solution. Furthermore, a Fabry-Perot laser chip with the wavelength of 1310 nm is used for light coupling test for the fabricated lensed fibers. Results show the coupling efficiency is up to 78% at working distance of 90 £gm while using the plastic lensed fiber (R =48 £gm), which is around 2 fold higher than that of a flat-end fiber. The coupling efficiency of glass lensed fiber (R =23 £gm) is up to 72% at working distance of 24 £gm, which is around 2.3 fold higher than that of a flat-end fiber. The proposed method is feasible of producing high-quality lensed optical fiber in a high throughput and low-cost way. The method proposed in the current study may give substantial impacts on fabricating lensed fiber in the future.

The thesis entitled "Studies on N-Hetero cyclic Compounds: (a) Reaction of 5,6,7,8-Tetrahydroisoquinolines with Vilsmeier Reagent and (b) Amide Induced in situ Alkylation of 5,6-Dihydroisoquinolines" is presented in two parts. Part I involves a study of the Vilsmeier reaction of 4-cyano-1,3-dihydroxy-5,6,7,8 tetrahydroisoquinoline derivatives, while Part II concerns the in situ alkylation of l-alkyl-4-cyano-3-methoxy-5,6- dihydroisoquinolines in presence of KNH2/liq.NH3.

Relative permeabilities for three-phase flow are commonly predicted from two-phase flow measurements using empirical models. These models are usually tested against available steady state data. However, the oil flow is unsteady state during various production stages such as gas injection after water flood. Accurate measurement of oil permeability([subscript ro]) during unsteady tertiary gas flood is necessary to study macroscopic oil displacement rate under micro scale events including double drainage, coalescence and reconnection, bulk flow and film drainage. We measure the three-phase oil relative permeability by conducting unsteady-state drainage experiments in a 0.8m water-wet sandpack. We find that when starting from capillary-trapped oil, k[subscript ro] starts high and decreases with a small change in oil saturation, and shows a strong dependence on both the flow of water and the water saturation, contrary to most models. The observed flow coupling between water and oil is stronger in three-phase flow than two-phase flow, and cannot be observed in steady-state measurements. The results suggest that the oil is transported through moving gas/oil/water interfaces (form drag) or momentum transport across stationary interfaces (friction drag). We present a simple model of friction drag which compares favorably to the experimental data. We also solve the creeping flow approximation of the Navier-Stokes equation for stable wetting and intermediate layers in the corner of angular capillaries by using a continuity boundary condition at the layer interface. We find significant coupling between the condensed phases and calculate the generalized mobilities by solving co-current and counter-current flow of wetting and intermediate layers. Finally, we present a simple heuristic model for the generalized mobilities as a function of the geometry and viscosity ratio. To identify the key parameter controlling the measured excess oil flow during tertiary gasflood, we also conduct simultaneous water-gas flood tests where we control water relative permeability and let water saturation develop naturally. The measured data and pore scale calculations indicate that viscous coupling can not explain completely the observed flow coupling between oil and water. We conclude that the rate of water saturation decrease, which controls the pore scale mechanisms including double drainage, reconnection, and film drainage significantly influences the rate of oil drainage during tertiary gas flood. Finally, we present a simple heuristic model for oil relative permeability during tertiary gas flood, and also explain how Stone I and saturation-weighted interpolation should be used to predict the permeability of mobilized oil during transient tertiary gasflood. / text

The Born-Oppenheimer approximation is a mainstay in molecular physics and chemistry and can be considered a two step process. The first step is to solve the electronic problem with nuclei fixed in space while the second step is to then determine the nuclear dynamics on a given electronic potential energy surface. This first-step calculation of the wavefunction and electronic energies for fixed nuclei has been at the center of modern quantum chemistry for decades. While the majority of chemical processes can be investigated by considering these single electronic surface dynamics, there exist problems in which the dynamics are not constrained to a single electronic surface. One such problem that justifies going beyond the typical adiabatic approximation is the determination of energy levels in systems with strongly coupled electronic states. While some work has been done using diabatic or quasidiabatic Hamiltonians to describe such systems, the work has historically been of qualitative accuracy. Model Hamiltonians have been constructed using experimental data to help calibrate the model parameters aided by the use of lower level adiabatic calculations to help inform the model. It is only within the last few years that theorists have been able to attempt parameterization of such models using only ab initio methods. The goal of this work is to develop a computational framework for the parameterization of quantitatively accurate quasidiabatic Hamiltonians based purely on ab initio information and apply it to a notoriously difficult problem that has plagued the theoretical community for decades -- high accuracy treatment of the energy levels of the NO₃ radical. In this dissertation, high-level ab initio calculations that employ the equation-of-motion coupled-cluster method in the single, doubles and triples (EOMIP-CCSDT) have been used in conjunction with a quasidiabatic ab initio approximation to construct a vibronic Hamiltonian for the strongly coupled X²A'₂ and B²E' states of the NO₃ radical. A quartic vibronic coupling model potential of the form advocated by Köppel et al. has been used to determine the energy levels of this system to quantitative accuracy when compared to experimental data. In order to obtain sufficiently accurate potential energy surfaces necessary to parameterize a quantitatively accurate model Hamiltonian, thousands of large calculations had to be run that do not fit in memory on even the largest HPC systems. The resulting large, out-of-core solves do not map to traditional systems in a way to enable any reasonable parallelization. As a result, a new MPI-based utility has been developed to support out-of-core methods on distributed memory systems. This and other advances in scientific computing form the basis of the developed computational framework. / text

A two-dimensional viscous-inviscid interactive boundary layer method is applied to three dimensional problems of flow around ducts and ducted propellers. The idea is to predict the effects of fluid viscosity on three dimensional geometries, like ducts, using a two-dimensional boundary layer solver to avoid solving the fully three dimensional boundary layer equations, assuming that the flow is two-dimensional on individual sections of the geometry. The viscous-inviscid interactive method couples a perturbation potential based inviscid panel method with a two-dimensional viscous boundary layer solver using the wall transpiration model. The boundary layer solver used in the study solves for the integral boundary layer characteristics given the edge velocity distribution on the geometry. The viscous-inviscid coupling is applied in a stripwise manner but by including the interaction e ffects from other strips. An important development in this thesis is the consideration of eff ects of other strips in a more rational and accurate manner, leading to improved results in the cases examined when compared to the results of a previous method. In particular, the effects of potentials due to other strips arising out of the three dimensional formulation are considered in this thesis. The validity of assuming two-dimensional flow along individual sections for application of viscous-inviscid coupling is investigated for the case of an open propeller by calculating the boundary layer characteristics in the direction normal to the assumed direction of two-dimensional flow from data obtained by RANS simulations. Also, a previous method which models the flow around the trailing edge of blunt hydrofoils has been improved and extended to three dimensional axisymmetric ducts. This method is applied to ducts with blunt and sharp trailing edges and to a ducted propeller. Correlations of results with experiments and simulations from RANS are shown. / text

The syntheses and catalytic properties of four new 1,2-acenaphthenyl N-heterocyclic carbene-supported palladium(II) catalysts are presented. The acenaphthenyl carbene can be prepared using either mesityl or 2,6-diisopropyl N-aryl substituents. In addition, two new heterogeneous analogs were synthesized with 2,6-diisopropyl N-aryl substituents that were anchored through the backbone to an insoluble silica-support. Comprehensive catalytic studies of the Suzuki coupling of aryl halides with aryl boronic acids were carried out. In general, the homogeneous diisopropyl-functionalized catalyst was found to exhibit superior selectivity and reactivity. A comparison of the performances of the aforementioned catalysts in toluene, dichloromethane and aqueous solutions are also presented. In organic solvents, the catalysts were found to be proficient for the homogeneous Suzuki coupling of aryl iodides, bromides and chlorides with boronic acids at low temperatures (35‒40 °C). Similar reactions that were carried out in aqueous media resulted in the formation of insoluble colloidal catalytic species. Nevertheless, these species still retained high activities in terms of in the Suzuki reaction with aryl chlorides. Moreover, the heterogeneous Pd precipitates can be easily recovered for subsequent use by means of filtration. The activation energies that were determined for the aryl bromide-based Suzuki reactions were found to fall in the range, 159.2‒171.2 kJ mol⁻¹ in organic solvents and 111.3‒115.9 kJ mol⁻¹ in water. The corresponding activation energy for the aryl chloride was found to be 321.8 kJ mol⁻¹ in aqueous media using the homogeneous diisopropyl-functionalized carbene catalyst. Conversely, the heterogeneous catalyst exhibited reactivity toward aryl iodides and bromides exclusively, and required significantly higher temperatures and catalyst loadings in both toluene and water. Additional experimental trials that were performed in tetrahydrofuran solution at lower temperatures resulted in substantially larger catalytic conversions. The heterogeneous catalyst allowed for easy separation and recovery. However, the catalyst exhibited a significant decrease in reactivity toward the aryl halides after two consecutive trials. / text

Waveguides are desirable components for energy transmission throughout the electromagnetic spectrum. This thesis experimentally examines a thick slot waveguide for THz guiding and field enhancement. The waveguide is machined from planar copper sheets using the novel technique of femtosecond laser micromachining. In-plane photoconductive THz coupling to a thick slot waveguide is demonstrated using Discontinuous Galerkin Time Domain (DGTD) simulation. The results reveal positive implications for broadband low-loss/dispersion transmission lines up to 1.5 THz. / Graduate / 0544 / 0607 / 0756 / levismith3@hotmail.com