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Part I Electrochemical charge transfer at a metallic electrode: a simulation study The factors which affect the rate of heterogeneous electron transfer at a metallic electrode in the context of Marcus theory are investigated through molecular dynamics simulations. The system consists of the ionic melt K3Eu2+ 0:5Eu3+ 0:5Cl5:5 sandwiched between two parallel plate platinum electrodes held at a preset electrical potential. The charges on the electrode atoms are variationally obtained through the method of Siepmann and Sprik [J. Chem. Phys. 102, 511 (1995)] which models the polarization of the electrode by the melt and maintains the condition of constant potential. A two-dimensional Ewald summation is employed to ensure that the absolute value of the potential is known, and the expressions derived by Kawata and Mikami [Chem. Phys. Lett. 340, 157 (2001)] are extended to allow for induced dipoles on the melt ions by their mutual interaction and the interaction with the electrode surface. The Marcus free energy curves are calculated for electron transfer events between a europium ion and the metallic electrode, and their dependence on the position of the redox ion and the applied potential examined. The system is consistently found to be in accord with the linear response regime. A moderately-ranged oscillatory character in the mean electrical (Poisson) potential is observed extending into the fluid, which is in marked disagreement with the predictions of existing mean-field (Gouy-Chapman) predictions. These oscillations are found not to be reflected in the calculated Helmholtz reaction free energy, which indicates that the Poisson potential is not the appropriate potential for discussions of the kinetics of electrode processes. The strong dependence of the reorganization energy on the position of the redox ion is traced to the image charge effect, and appears insensitive to the polarizability of the anion. Following the evolution of the Eu{Cl radial distribution function throughout a redox process reveals that the bond length in the transition complex is exactly in between those of the ground state reactant and product complexes. The potentials of mean force for the approach of a Eu2+ and Eu3+ ion to the electrode calculated through umbrella sampling are found to be in quantitative agreement with those calculated through the position-dependence of the respective concentration profiles. A method to parameterize a model of the interactions between the melt ions and the electrode surface from ab initio density functional theory calculations is described. The method is used to obtain a suitable interaction model for a system consisting of a LiCl liquid electrolyte and a solid aluminium electrode. The electrolyte is found to exhibit a potential-driven phase transition which involves the commensurate ordering of the electrolyte ions with the electrode surface; this leads to a maximum in the differential capacitance as a function of applied potential. Away from the phase transition the capacitance was found to be independent of the applied potential. Part II Are dipolar liquids ferroelectric? The observation of a very sharp low frequency spike in the hyper-Rayleigh spectrum (HRS) of strongly dipolar fluids, such as acetonitrile and water, has been interpreted as reflecting a very slowly relaxing component in the transverse dipole density. This suggestion is at variance with the expectation of dielectric theory for an isotropic fluid and has led to the speculation that the slow relaxation is associated with the reorganization of ferroelectric domains. Very large-scale molecular dynamics simulation ( 28000 molecules) have been carried out using a 3-site potential model of acetonitrile. The simulated fluid shows no suggestion of strong dipole correlations and domain structure. The dipole density correlations behave as predicted by normal dielectric theory and their spectra do not show the low-frequency feature seen in the HRS. In order to examine the characteristics of the spectra which would be seen in a ferroelectric domain, the acetontrile model was transmuted to more closely resemble a Stockmayer-like fluid with the same dipole density and a ferroelectric phase was observed. In this phase the dielectric spectra show (i) a high-frequency spectral feature due to librational motion of the molecules within a domain, and (ii) slowly-relaxing longitudinal and transverse polar modes, again at variance from the experimental HRS characteristics.

This thesis looks at the transverse flute as an instrument as well as flute music in the baroque period.

In this thesis the spark plasma sintering process (SPS) was used to press Mg2Si powder with Ni and Cu slices into alternating layer stacks. These stacks, once cut at an angle, are an artificially anisotropic material. This anisotropy provides transverse thermoelectric properties to the sample. The transverse transport properties were measured along with the individual component transport properties. The SPS process provided malleable samples that gave a power factors of for the Ni/Mg2Si stack and for the Cu/Mg2Si stack. These fall short of the theoretical calculations which would give the power factors as .0254 for the Ni/Mg2Si stack and .211 for the Cu/Mg2Si stack. It is theorized that eddy currents and interface resistances between the layers are the causes for these discrepancies.

Thesis advisor: John A. Baldwin / Khovanov homology and Heegaard Floer homology have opened new horizons in knot theory and three-manifold topology, respectively. The two invariants have distinct origins, but the Khovanov homology of a link is related to the Heegaard Floer homology of its branched double cover by a spectral sequence constructed by Ozsváth and Szabó. In this thesis, we construct an equivalent spectral sequence with a much more transparent connection to Khovanov homology. This is the first step towards proving Seed and Szabó's conjecture that Szabó's geometric spectral sequence is isomorphic to Ozsváth and Szabó's spectral sequence. These spectral sequences connect information about contact structures contained in each invariant. We construct a braid conjugacy class invariant κ from Khovanov homology by adapting Floer-theoretic tools. There is a related transverse invariant which we conjecture to be effective. The conjugacy class invariant solves the word problem in the braid group among other applications. We have written a computer program to compute the invariant. / Thesis (PhD) — Boston College, 2016. / Submitted to: Boston College. Graduate School of Arts and Sciences. / Discipline: Mathematics.

It has been proven by J.C.Criscione that constitutive relations(mixed approach) based on a set of five strain invariants (Beta-1, Beta-2, Beta-3, Beta-4, Beta-5) are useful and stable for experimentally determining response terms for transversely isotropic material. On the other hand, Rivlin’s classical model is an unsuitable choice for determining response terms due to the co-alignment of the five invariants (I1, I2, I3, I4, I5). Despite this, however, a mixed (Lagrangian and Eulerian) approach causes unnecessary computational time and requires intricate calculation in the constitutive relation. Through changing the way to approach the derivation of a constitutive relation, we have verified that using an Eulerian approach causes shorter computational time and simpler calculation than using a mixed approach does. We applied this approach to a boundary value problem under specific deformation, i.e. finite extension and torsion to a fiber reinforced circular cylinder. The results under this deformation show that the computational time by Eulerian is less than half of the time by mixed. The main reason for the difference is that we have to determine two unit vectors on the cross fiber direction from the right Cauchy Green deformation tensor at every radius of the cylinder when we use a mixed approach. On the contrary, we directly use the left Cauchy Green deformation tensor in the constitutive relation by the Eulerian approach without defining the two cross fiber vectors. Moreover, the computational time by the Eulerian approach is not influenced by the degree of deformation even in the case of computational time by the Eulerian approach, possibly becoming the same as the computational time by the mixed approach. This is from the theoretical thought that the mixed approach is almost the same as the Eulerian approach under small deformation. This new constitutive relation by Eulerian approach will have more advantages with regard to saving computational time as the deformation gets more complicated. Therefore, since the Eulerain approach effectively shortens computational time, this may enhance the computational tools required to approach the problems with greater degrees of anisotropy and viscoelasticity.

Multiple transverse fracturing along a horizontal well is a relatively new technology that is designed to increase well productivity by increasing the contact between the reservoir and the wellbore. For multiple transverse fractures, the performance of the well system is determined by three aspects: the inflow from the reservoir to the fracture, the flow from the fracture to the wellbore, and the inflow from the reservoir to the horizontal wellbore. These three aspects influence each other and combined, influence the wellbore outflow. In this study, we develop a model to effectively formulate the inter-relationships of a multi-fracture system. This model includes a reservoir model and a wellbore model. The reservoir model is established to calculate both independent and inter-fracture productivity index to quantify the contribution from all fractures on pressure drop of each fracture, by using the source functions to solve the single-phase gas reservoir flow model. The wellbore model is used to calculate the pressure distribution along the wellbore and the relationship of pressure between neighboring fractures, based on the basic pressure drop model derived from the mechanical energy balance. A set of equations with exactly the same number of fractures will be formed to model the system by integrating the two models. Because the equations are nonlinear, iteration method is used to solve them. With our integrated reservoir and wellbore model, we conduct a field study to find the best strategy to develop the field by hydraulic fracturing. The influence of reservoir size, horizontal and vertical permeability, well placement, and fracture orientation, type (longitudinal and transverse), number and distribution are completely examined in this study. For any specific field, a rigorous step-by-step procedure is proposed to optimize the field.

This thesis is to investigate in detail the frameworks of speed and lift control schemes of transverse flux linear switched-reluctance machine (TFLSRM), and to verify the validity of the resulting controllers by Matlab/Simulink simulation. Before the developments of adequate control parameters, the system inductance matrix and relative state equation regarding machine voltage and force operations were devised. By using the system linearized small signal model, and Routh stability criterion, the range for all parameters of controllers can be derived. Finally, to control the propulsive and lift forces simultaneously, a supplemental phase voltage adjustment scheme has also been provided to better the overall system performance.

The objective of this thesis is to integrate available commercial Software/Hardware package and to establish appropriate graphic user interface (GUI) for transverse flux linear switched-reluctance machine (TFLSRM) motion control. By changing the machine feedback signals, package will be matched with TFLSRM. The control unit of the whole system is based on digital signal processor (DSP) with its software interface being built up by Matlab/Simulink. Hence, users can operate this machine directly by observing the output result from computer monitor. By combining with suitable PI controller, friction variation can be eliminated and the control objectives of the TFLSRM under a desirable velocity also can be achieved.

This work investigated the characteristics of transverse modes and polarization of a VCSEL and attempted to control its transverse mode with optical feedback. The fundamental studies indicated that this solitary VCSEL's output consisted of two mutually orthogonal linear polarizations with different threshold currents and different transverse mode distributions. Furthermore, the temperature dependence of the transverse modes of the VCSEL revealed a better stability than that of edge-emitted lasers. In the mode controlling experiments, an iris was employed to select a specific transverse mode for feedback, resulting in an enhancement in the power of the feedback mode. A significant improvement was accomplished in the feedback of the fundamental mode of the major polarization component: the laser oscillated in a single mode with a side mode suppression ratio greater than 19.8 dB and with a depression of the relative intensity noise more than 20 dB/Hz. Nevertheless, a week feedback in the minor polarization component would stimulate more competition among transverse modes and degraded the performance of the VCSEL. Finally, no effect was observed in the orthogonal-polarization optical feedback experiment due to the excessively small of feedback ratio.