AN ANALYSIS OF FACTORS INFLUENCING REGIONAL LABOR FORCE MIGRATION, 1960-1970

Labor and Human Capital,

HIGH-ORDER INTEGRAL EQUATION METHODS FOR QUASI-MAGNETOSTATIC AND CORROSION-RELATED FIELD ANALYSIS WITH MARITIME APPLICATIONS

This dissertation presents techniques for high-order simulation of electromagnetic fields, particularly for problems involving ships with ferromagnetic hulls and active corrosion-protection systems. A set of numerically constrained hexahedral basis functions for volume integral equation discretization is presented in a method-of-moments context. Test simulations demonstrate the accuracy achievable with these functions as well as the improvement brought about in system conditioning when compared to other basis sets. A general method for converting between a locally-corrected Nyström discretization of an integral equation and a method-of-moments discretization is presented next. Several problems involving conducting and magnetic-conducting materials are solved to verify the accuracy of the method and to illustrate both the reduction in number of unknowns and the effect of the numerically constrained bases on the conditioning of the converted matrix. Finally, a surface integral equation derived from Laplace’s equation is discretized using the locally-corrected Nyström method in order to calculate the electric fields created by impressed-current corrosion protection systems. An iterative technique is presented for handling nonlinear boundary conditions. In addition we examine different approaches for calculating the magnetic field radiated by the corrosion protection system. Numerical tests show the accuracy achievable by higher-order discretizations, validate the iterative technique presented. Various methods for magnetic field calculation are also applied to basic test cases

CONSTRAINED DIVERGENCE-CONFORMING BASIS FUNCTIONS FOR METHOD OF MOMENTS DISCRETIZATIONS IN ELECTROMAGNETICS

Higher-order basis functions are widely used to model currents and fields in numerical simulations of electromagnetics problems because of the greater accuracy and computational efficiency they can provide. Different problem formulations, such as method of moments (MoM) and the finite element method (FEM) require different constraints on basis functions for optimal performance, such as normal or tangential continuity between cells. In this thesis, a method of automatically generating bases that satisfy the desired basis constraints is applied to a MoM formulation for scattering problems using surface integral equations. Numerical results demonstrate the accuracy of this approach, and show good system matrix conditioning when compared to other higher-order bases

Intellektuelle Anschauung und realer Verstandesgebrauch in Kants Inauguraldissertation

I will reinterpret the term ‘real use of the understanding’ in the outcome of the suspension of intellectual intuition. Kant applied both terms for the first time in the inaugural dissertation. The ‘objects’ of this use of the understanding thus obtain a more critical meaning and are transformed from substances to functions. Nevertheless, there is still a decisive difference between the inaugural dissertation and the critique of pure reason. Kant shifted his perspective rather than his subject. The question concerning facts (quid facti) turns into the question concerning legal matters (quid iuris). However, ‘noumena’ are no substances which exist independently of consciousness in the inaugural dissertation. Therefore, they must retain a critical meaning even after the Copernican turn. This essay aims to highlight this critical meaning by focusing on the reflective figure of intellectual intuition in the inaugural dissertatio

Binary-black-hole initial data with nearly-extremal spins

There is a significant possibility that astrophysical black holes with nearly-extremal spins exist. Numerical simulations of such systems require suitable initial data. In this paper, we examine three methods of constructing binary-black-hole initial data, focusing on their ability to generate black holes with nearly-extremal spins: (i) Bowen-York initial data, including standard puncture data (based on conformal flatness and Bowen-York extrinsic curvature), (ii) standard quasi-equilibrium initial data (based on the extended-conformal-thin-sandwich equations, conformal flatness, and maximal slicing), and (iii) quasi-equilibrium data based on the superposition of Kerr-Schild metrics. We find that the two conformally-flat methods (i) and (ii) perform similarly, with spins up to about 0.99 obtainable at the initial time. However, in an evolution, we expect the spin to quickly relax to a significantly smaller value around 0.93 as the initial geometry relaxes. For quasi-equilibrium superposed Kerr-Schild (SKS) data [method (iii)], we construct initial data with \emph{initial} spins as large as 0.9997. We evolve SKS data sets with spins of 0.93 and 0.97 and find that the spin drops by only a few parts in 10^4 during the initial relaxation; therefore, we expect that SKS initial data will allow evolutions of binary black holes with relaxed spins above 0.99. [Abstract abbreviated; full abstract also mentions several secondary results.

Analysis and modeling of green wood milling: Chip production by slabber

During the primary transformation of wood, logs are faced with slabber heads. Chips produced are raw materials for pulp paper and particleboard industries. Efficiency of these industries is partly due to particle size distribution. Command of this distribution is no easy matter because of great dependence on cutting conditions and variability in material. This study aimed a better understanding and predictionof chip fragmentation. It starts with a detailed description of cutting kinematic and interaction between knife and log. This leads to the numerical development of a generic slabber head. Chip fragmentation phenomena were studied through experiments in dynamic conditions. These experiments were carried out thanks to a pendulum (Vc = 400 m/min). It was instrumented with piezoelectric force sensors and high speed camera. Obtained results agreed very well with previous quasi-static experiments